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Master's Theses Graduate College

8-2012

Reservoir Characterization and Enhanced Oil Recovery Potential in Middle Devonian Dundee Limestone Reservoirs, Michigan Basin, USA

Abrahim Abduslam

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Recommended Citation Abduslam, Abrahim, "Reservoir Characterization and Enhanced Oil Recovery Potential in Middle Devonian Dundee Limestone Reservoirs, Michigan Basin, USA" (2012). Master's Theses. 21. https://scholarworks.wmich.edu/masters_theses/21

This Masters Thesis-Open Access is brought to you for free and open access by the Graduate College at ScholarWorks at WMU. It has been accepted for inclusion in Master's Theses by an authorized administrator of ScholarWorks at WMU. For more information, please contact [email protected]. RESERVOIR CHARACTERIZATION AND ENHANCED OIL RECOVERY POTENTIAL IN MIDDLE DEVONIAN DUNDEE LIMESTONE RESERVOIRS, MICHIGAN BASIN, USA

by

Abrahim Abduslam

A Thesis Submitted to the Faculty ofthe Graduate College in partial fulfillment ofthe requirements for the Degree ofMaster ofScience Department ofGeosciences Advisor: David A. Barnes, Ph.D.

Western Michigan University Kalamazoo, Michigan August 2012 THE GRADUATE COLLEGE WESTERN MICHIGAN UNIVERSITY KALAMAZOO, MICHIGAN

Date 07/09/2012

WE HEREBY APPROVE THE THESIS SUBMITTED BY

Abrahim Abduslam

ENTITLED Reservoir Characterization and Enhanced Oil Recovery Potential in Middle Devonian Dundee Limestone Reservoirs, Michigan Basin, USA

AS PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE

Master of Science DEGREE OF

Geosciences (Department) Dave Barnes Thesis Committee Chair

Geology

(Program) William B.flarrison Thesis Committee Member

Michael Grammer Thesis Committee Member

APPROVED

Date .U(A)ti1oa~ Dean of The Graduate College RESERVOIR CHARACTERIZATION AND ENHANCED OIL RECOVERY POTENTIAL IN MIDDLE DEVONIAN DUNDEE LIMESTONE RESERVOIRS, MICHIGAN BASIN, USA

Abrahim Abduslam, M.S.

Western Michigan University, 2012

Middle Devonian Rogers City and subjacent Dundee Limestone formations have combined oil production in excess of 375 MMBO. In general, hydrocarbon production occurs in two distinct reservoir types: 1) bottom water drive, fractured dolomite reservoirs in the Rogers City and 2) gas expansion drive, depositional facies controlled limestone reservoirs ofthe Dundee. The main objective of this study is to evaluate the enhanced oil recovery (EOR) potential in Dundee Limestone reservoirs on the basis of detailed geological reservoir characterization in several fields in the Michigan Basin. Seven main depositional facies were identified from core studies in six fields. Three of these depositional facies are productive reservoirs including: 1) shoal, 2) patch reef, and 3) peritidal. The average porosity and permeability of these reservoir facies is: 7%/14md; 7%/123md; and 9%/195md, respectively. Reservoir drive mechanisms, estimated primary recovery efficiency, and reservoir petrophysics suggest that Dundee reservoirs may be prospective EOR targets. It is proposed in this study that sedimentary lithofacies dominate the geological controls on reservoir properties in Dundee limestone reservoirs and that the interpretation ofprimary depositional facies contributes substantially to the prediction of EOR potential in these six large Dundee fields. Laterally persistent facies deposited in carbonate shoal (i.e., West Branch Field) and peritidal (i.e., Mt Pleasant, Wise, and North Buckeye fields) environments are most prospective while laterally discontinuous patch reef deposit (i.e., South Buckeye Field) are more problematic. Copyright by Abrahim Abduslam 2012 ACKNOWLEDGMENTS

This thesis project would not have been possible without the help, support, and patience of my principal advisor, and thesis committee members over the past two years. First, and for most, I wish to express my sincere gratitude towards my outstanding advisor, Dr. David A. Barnes. His invaluable leadership, support, attention to detail, and dedication to helping me successfully formulate and carry out this project. Deepest gratitude is also due to the members of my committee, Dr. William B. Harrison, III and Dr. G. Michael Grammer whose knowledge and

assistance helping make this study successful. I would like to acknowledge ExxonMobil, and the Institute of International Education (HE) and its staff, especially for the scholarship that provided the necessary financial support for accomplishing this Master of Science Degree. Special thanks also goes to the Department of Geosciences at Western Michigan University for their support and assistance since the start ofmy study in Fall, 2010. I would like to thank my graduate colleagues that I have worked with at Michigan Geological Repository for Research and Education (MGRRE): Steve Zdan, Kate Pollard, Shannon Towne, Beth Berg, and John Sosulski. They were invaluable over the years, and I look forward to continuing collaboration with them in the future. Last but not least, I would like to thank my wife Eman for her personal support and great patience at all times. My parents Mohamed and Fatima and my brothers and sisters who have given me their unequivocal support throughout, as always, for which my mere expression ofthanks likewise does not suffice.

Abrahim Abduslam

n TABLE OF CONTENTS

ACKNOWLEDGMENTS ii

LIST OF TABLES vi

LIST OF FIGURES vii

CHAPTER

I. INTRODUCTION 1

Summary ofthe Problems 1

Preliminary Hypotheses 2

Research Objective 3

II. REGIONAL SETTING 5

Michigan Basin 5

Devonian Stratigraphic Framework 9

Dundee Formation Stratigraphic Nomenclature 14

Previous Work 18

III. METHODOLOGY 23

Core Descriptions 23

Petrographic Analyses 24

Conventional Core Analyses 27

Wire-line Log 27

Carbonate Classification Schemes 28

Summary ofthe Methods 30

iii Table ofContents—continued

CHAPTER

IV. SEDIMENTOLOGY 32

Depositional Facies 32

Facies 1: Crinoidal skeletal wackestone (open marine) 33

Facies 2: Bioturbated peloidal grainstone/packstone (shallow protected marine) 35

Facies 3: Crinoidal grainstone (shoal) 38

Facies 4: Coral-stromatoporoid rudstone (reefflank) 41

Facies 5: Stromatoporoid boundstone (patch reef) 43

Facies 6: Skeletal wackestone (lagoon) 45

Facies 7: Fenestral peloidal grainstone/packstone (peritidal) 48

Diagenesis 52

Introduction 52

Diagenetic Alterations in the Dundee Limestone 53

Microbial Micritization 53

Burrowing 54

Dissolution-cementation 55

Fractures and Stylolitization 60

Depositional Environment Model 62

Carbonate Ramp 62

Sequence Stratigraphic Considerations 64

V. GEOLOGIC RESERVOIR CHARACTERIZATION 71

Reservoir Quality 72

iv Table ofContents—continued

CHAPTER

Porosity and Permeability 72

Diagenetic Controls on the Reservoir Quality 75

Reservoir Compartmentalization and Reservoir Distribution 77

Stratigraphic Correlations and Cross-sections 78

VI. DUNDEE HISTORIC PRODUCTION AND ENHANCED OIL RECOVERY (EOR) POTENTIAL 87

Historic Production 89

West Branch Field 90

South Buckeye Field 92

Mount Pleasant Field 93

Enhanced Oil Recovery (EOR) 95

VII. CONCLUSIONS 100

BIBLIOGRAPHY 102

APPENDICES

A. Core Descriptions 108

B. Core Charts (Adobe® Illustrator) 148

C. Core Photographs 175

D. Conventional Core Analysis 183

E. Cross-sections 222

v LIST OF TABLES

1. Stratigraphic section ofthe Rogers City Limestone, Dundee Limestone and overlying Bell Shale from outcrop in northeast Michigan 15

2. Cores used in this study 26

3. Dunham classification ofcarbonate rocks 2

vi LIST OF FIGURES

1. Location of the study area illustrating the targeted Middle Devonian Dundee Oil Fields 4

2. The major structural features ofthe Michigan Basin 6

3. Basement province map ofthe southern Peninsula ofMichigan 8

4. Structure map of North and South Buckeye oil fields in Gladwin County, Michigan 9

5. Proposed paleogeography distribution map, showing that the Michigan Basin was located at 30° south latitude during the Middle Devonian 10

6. Stratigraphic column of the Michigan Basin with the Rogers City and Dundee formations highlighted in red circle 13

7. Slabbed core and thin-section showing the Rogers City and Dundee contact from Schember-Shears #3, South Buckeye Field 15

8. Cross-section showing the contact between Rogers City and Dundee: the contact is readily picked in the presence of anhydrite capping the Dundee unit in the western part ofthe Basin (blue box) 17

9. Map of the Michigan Basin showing the spatial distribution of Dundee depositional environments and cross-sectional (K-L) view of the transitioning lithologies 19

10. Classification ofcarbonate pore types 29

11. Crinoidal skeletal wackestone facies (open marine) 34

12. Cross plot ofporosity and permeability measurements from whole core analyses ofcrinoidal skeletal wackestone facies 35

13. Bioturbated peloidal grainstone/packstone (protected shallow marine) 37

14. (A) Slabbed core illustrating the crinoidal grainstone tempestites interbedded with burrowed skeletal peloidal grainstone facies 37

vn List ofFigures—Continued

15. Cross plot ofporosity and permeability measurements from whole core analyses ofburrowed skeletal, peloidal grainstone/packstone facies 38

16. Crinoidal grainstone facies (shoal) 40

17. Cross plot ofporosity and permeability measurements from whole core analyses ofcrinoidal grainstone facies 40

18. Coral-stromatoporoid rudstone facies (reefflank) 42

19. Cross plot ofporosity and permeability measurements from whole core analyses ofreefflank facies 42

20. Stromatoporoid boundstone facies (patch reef) 44

21. Cross plot ofporosity and permeability measurements from whole core analyses ofstromatoporoid boundstone facies 45

22. Slabbed core showing a sharp stylolitic contact between the fenestral peloidal grainstone/packstone facies and skeletal wackestone facies 47

23. Skeletal wackestone facies (lagoon) 47

24. Cross plot ofporosity and permeability measurements from whole core analyses ofskeletal wackestone facies 48

25. Fenestral peloidal grainstone/packstone facies (peritidal) 50

26. Cross plot ofporosity and permeability measurements from whole core analysis offenestral, peloidal grainstone/packstone facies 51

27. The thin-section photomicrograph showing an example of fenestral vugs filled by fine grained micritic internal sediment (red arrow) and the remnant pore spaces within the fenestrae filled with sparry calcite (yellow arrow) 51

28. The micrite envelopes of the outer part of the shell are a result of microbial microboring and infilling ofthe holes by micrite 54

Vlll List ofFigures—Continued

29. (A) An example ofpredominantly intraparticle porosity in crinoid stem and stromatoporoid (yellow arrow) (B) Crinoid fragments and other skeletal fragments, including mollusks, are dissolved leaving abundant moldic porosity (yellow arrow) in relatively fine grain matrix 56

30. The open galleries of the stromatoporoids are extensively occluded by calcite cement (yellow arrows) in facies 3 ofthe North Buckeye Field 56

31. Fenestral fabric in tidal flat facies showing fenestral porosity (Fs) in light blue that is larger than the associated peloidal texture 57

32. Example of meteorically leached mollusk shells resulting in moldic porosity in the crinoidal grainstone facies 58

33. The syntaxial overgrowth on crinoid ossicles (Cri) has reduced most of pre-existing interparticle porosity (yellow arrows) 59

34. The presence of fractures (when unhealed with calcite cement) in many cases, can greatly increase the permeability ofthe rock 61

35. Thin-section photomicrograph of large amplitude stylolites typical of many stylolite solutions seems in carbonate mud matrix 61

36. Depositional setting for the seven depositional facies ofthe Rogers City and Dundee Limestone 63

37. Idealized vertical stacking patterns ofseven facies seen within the cores examined in this study 68

38. Stacking pattern in different facies areas/fields observed in the Rogers City and Dundee interval from the six fields 69

39. Changes in sea level recorded in the Middle Devonian deposits in Givetian stage, red star shows the proposed Rogers City and Dundee contact at approximately 390 Ma 70

40. All core measured porosity-permeability data with the three reservoir facies highlighted 75

41. Stratigraphic cross-section showing inferred lateral continuity of the fenestral reservoir facies 81

IX List ofFigures—Continued

42. Modern analog from the Persian Gulf is used to demonstrate interpretations oflateral continuity in peritidal facies 82

43. Stratigraphic cross section (A- A') across South Buckeye Field showing lateral variations in the stromatoporoid boundstone facies (marked in yellow) 85

44. Example ofmodern patch reefcomplex in the Belize coast 86

45. Average per well water production from representative fields with two distinct trends of relatively high water production per well from inferred bottom water drive in Rogers City (RGRC) dolomite Fields (Fork, Vernon, Crystal, and Deep River Fields) vs. relatively low water production from probable gas expansion drive in Dundee (DUND) Limestone Fields (West Branch and South Buckeye Fields 88

46. Performance history of the West Branch Dundee reservoir showing the oil production per year (green line) associated with primary and secondary annual decline (pink line). In the West Branch Field, the waterflood began in 1966 91

47. Performance history of the South Buckeye Dundee reservoir showing the annual oil production (green curve) and annual water production (blue curve) associated with annual decline (pink line) 93

48. Performance history of the Mount Pleasant Dundee reservoir showing the annual oil production (green curve) and annual water production (blue curve) associated with 4.5% annual decline (pink line) 94

49. Example ofthree wells ofthe fenestral facies showing the heterogeneity (porosity and permeability) within a single well 99

x CHAPTER I

INTRODUCTION

Summary ofthe Problems

In carbonate reservoirs, the heterogeneity of reservoir rock properties is a

fundamental complexity that complicates the effective production of hydrocarbon.

Therefore, this research is focused on understanding the geological origin of heterogeneity on the basis of detailed sedimentologic, petrophysical, and petrographic

study ofMiddle Devonian Dundee carbonate reservoirs.

Middle Devonian Dundee Limestone reservoir facies in the Michigan Basin

are very heterogeneous and have confounded reservoir quality prediction in most

important hydrocarbon targets. Generally, prediction of vertical and lateral geological heterogeneity of Dundee Limestone reservoirs and the consequent variation in petrophysical properties, including porosity and permeability remains a major problem for exploration and especially, effective production practices. Furthermore, a better understanding of the regional and in-field distribution of reservoir facies and reservoir quality in the Dundee can be useful during the enhanced recovery stage of production, when the detailed understanding of internal heterogeneity of reservoir facies can be used to increase hydrocarbon recovery from remaining oil in the most important producers in the Michigan Basin. Preliminary Hypotheses

Addison (1940) and Curran and Hurley (1992) describe production in the

Dundee Limestone Formation from several pay zones with considerable variation in

thickness, lateral continuity and petrophysical properties. Syndepositional local

structures may have resulted in limited lateral continuity of some, but not all,

reservoir facies. For instance, the presence of patch reef facies may indicate isolated

and non-continuous facies that pinch out on a spatial scale of less than 100 meter

associated with local paleobathymetry highs. Elsewhere, in the absence of patch reef

reservoir facies, grainstone reservoir facies may have greater lateral continuity. The

geometry of facies distribution and reservoir properties are attributable to variable

depositional environments and diagenetic alteration in different Dundee Limestone

fields. In particular, it is uncertain if the key control on reservoir quality is

depositional facies, or syndepositional and postdepositional processes (physical-

chemical) ofburial diagenesis.

This study undertakes a sub-regional study of the Dundee Limestone (i.e.

detailed geological and petrophysical characterization) in order to discriminate

between these hypotheses. This will provide a better understanding of reservoir quality in order to better evaluate the most prospective EOR targets in Dundee

Limestone oil fields in the Michigan Basin.

Thefundamental questions addressed in this study are:

1. What are the important reservoir facies and petrophysical properties of

reservoir facies in the Dundee Limestone?

2. What is the spatial distribution and geometry of Dundee heterogeneity in

reservoirs? 3. What petrophysical and reservoir geometry properties are most prospective

for EOR in the Dundee?

Research Objective

The main objective of this study is to evaluate EOR potential with a focus on

reservoir petrophysics and geometry in several representative Dundee oil fields.

Previous studies have addressed individual reservoir facies, determining the

calcite/dolomite ratio, and production characteristics in Dundee oil fields. However, this

research is an attempt to determine sedimentary lithofacies in high resolution scale

through the development of reservoir characterization method for EOR, and to create a

robust depositional model. This integrated approach uses representative core

observations, petrophysical data, core to wire-line log correlations, and the comparison

of production history data to geological reservoir characterization data to understand

diverse Dundee Limestone reservoirs facies.

A better understanding of vertical and areal porosity and permeability

distribution is significant in planning and implementing waterflood, or CO2 Enhanced

Oil Recovery projects in different Dundee oil reservoirs. The petrophysical properties are the key to prediction ofreservoir quality and heterogeneity, and to the assessment of potential reservoir, production, and ultimate recovery. Furthermore, EOR projects can be better designed to take advantages of the discontinuous reservoir facies geometry

(i.e., patch reef).

This study has determined sedimentary lithofacies and the reservoir properties in six large Dundee oil fields in which primary depositional facies dominate the geological control on reservoir properties. These fields include Mt Pleasant, Wise,

South Buckeye, North Buckeye, Butman, and West Branch fields, which are located

3 in the central Michigan Basin within Isabella, Midland, Gladwin, and Ogemaw

Counties (Figure 1).

The intensive study of the petrophysical properties and spatial geometry of the reservoir facies in several Dundee limestone reservoirs provide a better insight for the assessment of EOR potential within different Dundee Limestone reservoirs in the

Michigan Basin.

CORE 15 O • Butman

ARENAC

GLADWIN Buckeye North

iBuckeye South

BAY

MIDLAND

Figure 1. Location of the study area illustrating the targeted Middle Devonian Dundee Oil Fields. The cores used in this study are marked by purple circle. CHAPTER II

REGIONAL SETTING

Michigan Basin

The Michigan Basin is a large, nearly circular, intracratonic Basin in the North

America craton. The Basin is encircled by the Canadian Shield to the north, the

Kankakee arch to the south, Findlay-Algonquin arches to the east and southeast

(Figure 2), and to the west and northwest by the Wisconsin arch and Wisconsin

Highland (Cohee and Landes. 1958). The total area of the Basin is 80,000 mi2

(207,000 km2) which contains up to 16, 000 ft (4800 m) of the Paleozoic sedimentary rocks. The Basin is predominantly Cambrian marine siliciclastics overlain by Early

Ordovician to Middle Devonian carbonates and evaporites (Cohee and Landes, 1958;

Catacosinos et al., 1990). It has been noted that carbonate rocks are the predominant

lithology in the Michigan Basin (Rullkotter et al., 1986). A Pre-Cambrian complex of igneous and low grade meta-sedimentary rocks occurs within a major north-northwest to south-southeast trend associated with a basement gravity anomaly located in the central portion of the Michigan Basin. This anomaly is interpreted as a failed

Proterozoic rift system and a portion of the Mid-Continent Rift (Fowler and Kuenzi,

1978). Faults and fractures in the Basin mostly trend northwest to southeast and are associated with the Paleozoic anticlines. These structures characterize the intrabasinal structural grain ofthe Michigan Basin (Catacosinos et al., 1990). Figure 2. The major structural features of the Michigan Basin. Black ring shows the approximate extent of the Michigan Basin (Modified from Catacosinos etal., 1990).

Much work has been done on characterizing the structural geology of the Michigan Basin (Pirtle, 1932; Cohee and Landes. 1958; Hinze and Merritt, 1969; Hinze and Kellogg, 1975; Prouty, 1983; Catacosinos et al., 1990). The Michigan

Basin is characterized by a dominantly northwest to southeast structural trend. Hinze

6 and Kellogg (1975) concluded that the structural phenomenon is a reflection of the northwest to southeast structural grain in the Precambrian basement and the influence ofsubsequent Paleozoic horizontal stress.

Based on the lithologic data collected from drill holes and geophysical data,

Hinze and Kellogg (1975) divided the Precambrian basements province into four major basement structures: 1- Grenville province in the southeast, 2- Keweenawan rift zone which transects the Basin in a northwest-southeast trend, 3- Central province in the southwest and 4- Penokean province in the north (Figure 3).

The general structure interpretations present in the study area are based on mapping the top Rogers City, a distinctive boundary below the superjacent Bell Shale in the gamma ray log. These formation tops were picked from wire-line log data. The basement structural highs trend northwest-southeast and created a possible substrate for patch reef buildups in the Devonian (Catacosinos et al., 1991). Montgomery

(1986) noted that the South Buckeye field is present on a positive structure corresponding to the major northwest-southeast trend in the central Michigan Basin

(Figure4), whereas in the nearby North Buckeye field the axis of the anticlinal structure is transverse to the regional trend. In the West Branch field, about 30 mi (48 km) northeast ofNorth and South Buckeye fields (Figure 1), Curran (1990) described an asymmetrical anticline with a northwest- southeast trend. The best example of the larger structural northwest-southeast trend is the Mt Pleasant field, which is conceivably related to the basement movements (Little, 1986). MAFIC VOLCANIC ROCKS

MAFIC EXTRUSIVE AND INTRUSIVE ROCKS

Penokean (1.6-1.8 BY}

Keweenawan{l.QS-1.1B.Y)

Grenville<0.8-1.1 B.Y)

entral(U-1.5B.Y ^^Predominant Structural trend

Figure 3. Basement province map of the southern Peninsula of Michigan (Modified from Hinze et al., 1975). filW ft 11

KEY —— TowraNp boundaries Contour interval: 20 feet Contoured on the base of the Belt Shale

;Ki!OfTw?te r 1.6 R1W R1E

Figure 4. Structure map of North and South buckeye oil fields in Gladwin County, Michigan (McCloskey, 2012).

Devonian Stratigraphic Framework

Devonian strata represent the second most prolific oil producing units of the

Michigan Basin. Middle Devonian oil producing formations have several significant reservoir and seal systems, and some of these formations are also EOR and CO2 sequestration targets. The intracratonic Michigan Basin during the Devonian (385 million years)

was located 20-30 degrees south of the equator (Figure 5). The proposed

paleogeographic distribution map for the Middle Devonian suggest that the Michigan

Basin was located in shallow tropical marine environments, which promotes

carbonate sedimentation (Scotese, 1984 and Blakey, 2005).

Figure 5. Proposed paleogeography distribution map, showing that the Michigan Basin was located at 30° south latitude during the Middle Devonian. Brown and green is the land mass, dark blue is deeper water and light blue is shallower water. Red square represents the location of the Michigan Basin (After Blakey, 2011).

10 Several regional stratigraphic studies have been conducted in the Michigan

Basin (Fisher, 1969; Gardner, 1974; Lilienthal, 1978; Catacosinos et al., 1990). The

Upper and Middle Devonian strata in the Michigan Basin are overlain by

Mississippian strata, while the lower Devonian is generally absent (Figure 6). The

only remaining portion of Lower Devonian beds are those of the deeply eroded

Garden Island Formation (Lilienthal, 1978). Devonian strata in the Michigan Basin

are underlain by the sequence-bounding base Kaskaskia unconformity, which

separates Silurian Bass Islands Group strata from superjacent Devonian rocks (Ehlers,

1945). The Middle Devonian Dundee Formation is a complex carbonate succession that is stratigraphically underlain by the Detroit River Group and overlain by the

Traverse Group.

The Detroit River Group consists ofmixed carbonate and evaporite strata with

an average thickness of 1100 feet (335m) in the central Basin (Addison, 1940). The

Detroit River Group contains three stratigraphic units: the Sylvania Sandstone at the

base, consisting predominately of well sorted, fine to medium-grained sandstone

interbeded with cherty carbonate sediments (Catacosinos et al., 1991). The

Amherstburg Formation in the middle primarily composed of limestone and varying

amounts of dolomite (Catacosinos et al., 1991), and the upper-most Lucas Formation comprising mainly evaporite and dolomite sediments, which are interpreted as being

deposited in a mosaic of shallow water restricted environment (Catacosinos et al.,

1991). The Dundee Limestone is readily distinguished from anhydrite or other restricted and evaporitic lithologies of the underlying Lucas Formation (Gardner,

1974).

The Middle Devonian Dundee Limestone formation is overlain by the Bell

Shale Formation. The Dundee carbonates (more than 400 ft thick in the eastern part of

11 the Basin) have been subdivided into two units in the eastern part of the Basin, the

Dundee Formation is subdivided into the Rogers City and Dundee Limestone units

(Ehlers and Radabaugh, 1938; Gardner, 1974), which will be discussed in more detail

in the following section.

Traverse Group in the subsurface of the Michigan Basin was subdivided into three units: the Traverse Formation at the top, the Traverse Limestone in the middle,

and the Bell Shale Formation at the base. The Bell Shale, which is underlain by the

Rogers City Limestone, is fossilliferous grayish shale with variable thickness ranging

from 10ft- 80ft and pinches out toward the southwest (Lilienthal, 1978; Catacosinos

et.al, 1991). The Bell Shale is interpreted as being deposited on a shallow shelf with

muddy influx sources to the east (Gardner, 1974). The Bell Shale and the Rogers City

contact is one ofthe most distinctive log picks in the Michigan Basin (Figure 8).

12 GEOLOGIC TIME SUBSURFACE NOMENCLATURE DOMINANT LITHOLOGY PERIOD EPOCH STAGES FORMATION GROUP

5 Bayport Ls Meramecian a Late Q. Michigan Fm (ft i/> Osagian Marshall Ss

\r> Coidwater Sh l/> Early Kinderhookian Sunbury Sh

EHsworthSh Berea Ss £

(western! Bedford Sh »

Chautauquan >per Mbr Late achine Mbr

Paxton Mbr

— ""Jorvoocl Mb Senecan

—:

Traverse Ls Traverse Gr Erian i ;tr'i;j4iTi4xu'l^'cx'o^-Xi: !''';i!i;i;:;.:;;::: !i;i:i;;;:;i,i:i;i;.::;c:::..:. • EX•uil t>.'T'.», i•''' ?

Middle

Rpll <^h Rogers City

Dundee Ls

Lucas Fm

Detroit River Gr ' ,'"'JT*j Amherstburg Fm Ulsterian Sylvania Ss -•« '-• "v- -i- . Bois Blanc Fm

Early Garden Island Fm

1 HWMMDWWW WMMMMV

undifferentiated Bass Islands Gr Late

LEGEND

• Odomitic

....'.•: "::Conglomerit!C

l-TvL "

Figure 6. Stratigraphic column of the Michigan Basin with the Rogers City and Dundee formations highlighted in red circle (modified from Catacosinos etal., 1990). 13 Dundee Formation Stratigraphic Nomenclature

The stratigraphic nomenclature that is applied to the Dundee interval is based

upon the outcrop and subsurface investigations. The Dundee Limestone and the Rogers

City formations are the units of interest and are considered as two distinct formations,

the Rogers City and the Dundee Limestone formations throughout this study.

The term Dundee Limestone was first proposed by Lane (1893) to describe

outcrops in the southeastern Michigan near the town of Dundee. From the outcrop

studies in northeast Michigan, Ehlers and Radabaugh (1938) described that the upper

part of the Dundee Limestone is characterized by two distinct types of gastropods:

Omphalocirrus manitobensis and Buchelia tyrell (fauna not present in the upper

portion ofthe Dundee Limestone) which is different from the fauna in the lower part of the Dundee. Based on these observations, the Dundee was subdivided into the upper

Rogers City and the lower Dundee units. The authors described the Rogers City as a crystalline fine to medium-grained, gray limestone, with discontinuous alternating

bands ofthinly bedded magnesium-rich limestone (Ehlers and Radabaugh, 1938, Table

1). In the subsurface, Curran and Hurley, (1992) conducted a detailed study of eleven cores at West Branch field in Ogemaw County. They differentiate between the

Rogers City (above) and the Dundee (below) units in the subsurface through the recognition of a mineralized, bioeroded hardground surface (Figure 7), which places open marine (Rogers City) on top of the shallow platform Dundee Limestone. This

bioeroded hardground surface is interpreted as a depositional hiatus or a platform drowning event. The Dundee Limestone was partially lithified, before the deposition of the overlying Rogers City Limestone. The Rogers City/Dundee contact was well documented in the several studied cores in this project.

14 Table I. Stratigraphic section ofthe Rogers City Limestone, Dundee Limestone and overlying Bell Shale from outcrop in northeast Michigan (After Ehlers and Radabaugh, 1938).

Unit Bed | Thickness (cm) j Lithology -i— Bell 30.4 Shale, calcareous, bluish gray and abundantly fossiliferous Shale i Limestone, buffgray to bull, medium grained, fairly 1493.5 thickbedded and porous, containing some fossils Limestone,gray, finely crystalline,dense and thick bedded, 121.9 containing some fossils Limestone. Lower 2-3 feet mottled buffand bufl-gray, magnesian and thin-bedded, upper6 feet less mottled and less 259.0 V magnesian and thicker bedded than underlying beds,

Z containing some fossils CD O Dolomite, with discontinuous, alternating bulTand buff-gray 243.8 bands, fine-grained and thin-bedded, containing some fossils Limestone, gray, weathering to a buffgray, composed of 195.5 numerous shells ofbrachiopods and a smaller number ofother invertebrates Limestone, gray, weathering buffgray, with few chert 60.9 nodules, containing somefossils

o a> Limestone, buff gray to buff, weathering to brown, and •a 1798.3 c thickbedded, containing some fossils 3 2194.5 Limestone, buffgray to gray, mottled, dense and somewhat magnesian in lowerpari,containing somefossils

Total 6398.2

Figure 7. Slabbed core and thin-section showing the Rogers City and Dundee contact from Schember-Shears #3, South Buckeye field. This hardground may also be present along a mineralized stylolite seam, Sty= Stylolite, Pel= Peloids (picture courtesy of McCloskey, 2012)

15 Kirschner and Barnes (2009) established three hierarchical procedures using wire-line logs to distinguish between the Rogers City and Dundee units (Figure 8) in the subsurface: in the presence of anhydrite capping the Dundee unit in the western part of the Basin, the contact between these two units is readily picked. However, in the absence of anhydrite in the central and eastern part of the Basin a distinct break from essentially zero porosity in the Rogers City in the calibrated neutron porosity log to a more porous section in the Dundee. And finally a distinct gamma ray spike when porosity logs are unavailable or the Rogers City and Dundee are both dolomitized is useful to separates the Rogers City and Dundee contact.

The Rogers City interval in the central and eastern part of the Basin is mainly considered a nonproductive, low porosity limestone. The Dundee unit in the central

Basin is chiefly dolomitized, whereas to the east, the amount of dolomite is sharply diminished or highly localized (Montgomery et al., 1998).

16 35311 37672 36839 34500

BAKER DURKEE, B M 1873Mb MCDONALD <4810MI: KRYSZAK

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DUND

LUCS

Figure 8. Cross-section showing the contact between Rogers City and Dundee: the contact is readily picked in the presence ofanhydrite capping the Dundee unit in the western part ofthe Basin (blue box). GR (track 1 with shaded yellow to brown for increasing GR response), which makes a distinct separation between Rogers City and Dundee unit (red box), and makes a distinct separation between Bell Shale and underlain Rogers City (red circle). NPHI (track2) provides a distinct break from zero porosity in the upper Rogers City to more pores section in lower Dundee unit (black box). RHOB (track 2 green line) record the much higher density values for the anhydrites in the Lucas Formation which separate Lucas formation from overlain Dundee Limestone (blue circle). NPHI-RHOB separation in limestone (shaded blue) calibrated logs indicates dolomite (shaded pink) when associated with low GR readings and RHOB<2.9.

17 Previous Work

Gardner (1974) studied the stratigraphic relationships and the depositional

environments of the Middle Devonian stratigraphy in the Michigan Basin. His

interpretations of the depositional environments were based on lithofacies,

sedimentary structures determined from cores, and constructed isopach maps using

wire-line logs. Gardner determined that the depositional history of the Middle

Devonian strata can be related to stages one and two of the Kaskaskia Sequence.

Gardner described the Dundee as a biostromal shelf carbonate, with predominately

dark, fine grained offshore facies to the east and sabkha and lagoonal facies to the

west. In his model (Figure 9) Gardner interpreted the overall depositional setting of the Dundee as an east to west transgressive system across the Michigan Basin with a

brief regressive stage, which results in the deposition ofthe Reed City anhydrite in the western part ofthe Basin.

Montgomery (1986) studied the Dundee depositional facies and porosity relationships in the South Buckeye Field. He noted that the distribution ofthe oil producing zones in the Dundee Limestone was controlled by the primary depositional

facies and the structural influence. Montgomery also interpreted that the pay zones of the South Buckeye Field were developed by organic buildups on top ofpreexisting

structure. These interpretations were based on his observations in 12 conventional cores. The four major facies Montgomery identified in Buckeye Field were: 1) stromatoporoid boundstone; 2) skeletal grainstone/packstone; 3) nodular micritic wackestone/mudstone; and 4) fenestral pelletal packstone. Lagoon ^ P = 1.13-1.20

Laminated CaS04 precipitate, Biocalcarenites and calcisiltites Dolomitization by seepage reflux- Decreasing grain size and increasing ion through porous, transgressive, dark color seaward biostromal deposits

Figure 9. Map of the Michigan Basin showing the spatial distribution of Dundee depositional environments and cross-sectional (K-L) view of the transitioning lithologies. Dundee facies were deposited in transgressive sequence that extended across the Michigan Basin with a briefregressive stage that allowed for the deposition of the Reed City anhydrite in the western part ofthe Basin (modified after Gardner, 1974).

19 Curran and Hurley (1992) studied the sedimentology, facies distribution, and

porosity development in the Dundee reservoir in West Branch Field. Based on data

collected from eleven cores and log correlations, six facies were recognized: 1)

crinoidal grainstones; 2) skeletal-peloidal grainstones and packstones; 3) skeletal

wackestones; 4) restricted-fauna mudstones and wackestones; and 5) stromatoporoid

coral rudstone, and 6) fenestral-cryptalgal laminites. This last facies was

volumetrically insignificant as it was located below the oil water contact. Curran and

Hurley suggested that the Dundee reservoir in the West Branch Field was deposited in

normal marine conditions and added that the most productive zone in the reservoir

originated from primary porosity in lenticular beds ofskeletal grainstones and reef

related boundstones. They described the contact area between the Dundee Limestone

and the overlying Rogers City unit ofthe Dundee Formation as a disconformity

consisting ofa pyritized bioeroded hardground. They also found that the top 10-15ft

(3-4.5 m) ofthe Dundee Formation below the Rogers City unit contains pervasive

amounts ofdolomite, resulting in high porosity and low permeability facies. Curran

and Hurley concluded that the dolomitization in the Dundee occurred as an early

facies-related feature formed before the deposition ofthe Rogers City Limestone.

Wood et al. (1996) and Montgomery et al. (1998) stated that most of the wells

in the Dundee were drilled in 1930s and 1940s with initial production rates varying

from 2000-9000 bbl/day due to solution enhanced porosity in some areas (i.e. Rogers

City Dolomite). They observed that excellent primary interparticle porosity occurs in other places, and high permeability fractures are also present. They also reported that, wells in many of the Dundee Fields (producing from both Rogers City and Dundee reservoirs) throughout the Basin were abandoned, due to the aggressive, early development practices, coupled with the strong water drive which resulted in water

20 coning. This water coning caused a significant volume of oil (about 60-80% of

potentially producible oil) to be bypassed and considered unrecoverable between

wells in some fields (Montgomery et al., 1998). Based on information from the

Cronus Development Tow# 1-3 HD-1 well in Crystal Field (the first horizontal well

in this field), and supplemented with the preexisting field information, Montgomery

et al. (1998) concluded that horizontal drilling was a feasible technique to

significantly enhance production from Dundee reservoirs(i.e. Rogers City Dolomite)

in the Michigan Basin. They estimated that more than 200,000 bbl of recoverable

reserves can be extracted from the Tow #1-3 in Crystal Field. In addition, two

horizontal wells were drilled in another portion of Crystal Field, but those wells

produced mostly water with minute amounts of oil. Montgomery et al., (1998)

believed that these wells were drilled near the oil water contact or crossed fractures that extended into the water saturated zone. Montgomery et al., (1998) reported that

by early 1998 the initial production from 15 horizontal wells drilled in various

Dundee reservoirs ranged from 5-127 bbl/day. Based on these results, they concluded that successful horizontal drilling in the Rogers City dolomite and Dundee Limestone reservoirs requires further study of the reservoir complexity, structure distribution, and oil water contacts.

Luczaj et al., (2006) studied hydrothermal fractured dolomite distribution and its characteristics in the Dundee reservoir rocks of the central Michigan Basin using core description and fluid-inclusion microthermometric methods. Luczaj et al., (2006) grouped the Rogers City and Dundee units together as the Dundee Formation, whereas in this thesis the Rogers City and Dundee used as separate units. Luczaj et al. stated that the Dundee Formation contained fracture-controlled and facies-controlled reservoirs, and added that in the central Michigan the fractured dolomite reservoirs

21 had tremendous oil production in the Michigan Basin. These authors documented that the saddle dolomite in the Dundee occurs as a result of hydrothermal fluid circulation along the fractures and faults with temperature ranging from 120-150 degrees centigrade. In addition, they concluded that the occurrence of the fractures and the saddle dolomite precipitation in the Dundee Formation accounts for reservoir development because both occurred prior to oil migration and reservoirs filling.

Consequently, they concluded that dolomitization in the Dundee Fields (Rogers City dolomite) ofthe central Basin were related to deep-seated fault and fracture systems.

Kirschner and Barnes (2009) characterized the geology and the petrophysical properties of the Dundee Limestone by using wire-line logs and conventional core analysis including porosity and permeability data. They observed that the separation of the Rogers City and the Dundee Limestone can b made by the wire-line log signatures and added that the Dundee Limestone is characteristically porous while the

Rogers City typically has little to no porosity when found as limestone lithology.

Further, Kirschner and Barnes documented an estimated CO2 storage capacity of

0.13Gt in the Rogers City and 1.88Gt in the Dundee limestone. They concluded that the Dundee Limestone is an important geological sequestration reservoir target compared to the Rogers City.

22 CHAPTER III

METHODOLOGY

This study utilized several phases of sampling, analysis, and interpretation of core for reservoir characterization. The core data was gathered from Michigan

Geological Repository for Research and Education (MGRRE) at the Western

Michigan University. There are fifteen cored wells within the selected study area available at MGRRE core lab and these cores were studied in detail in this research

(Appendix A, B). Generally the core footages cover most ofthe producing interval of the Dundee Limestone and part of the overlying Rogers City Limestone. However, some ofthe slabbed cores contain a number ofmissing sections that were removed for description and other testing. The conventional cores analysis (porosity and permeability) and petrophysical wire-line logs were available at MGRRE.

Core Descriptions

In this research, fifteen cores were selected based upon the presence of interval coverage, whole core analyses and an available suite of wire-line logs. A detailed geologic description was performed on approximately 1100 feet (335 m) in fifteen cores from six Dundee fields (Table2). Insights from core examination were supplemented with inspection of 26 cores in South Buckeye field from McCloskey

(2012), and an additional 11 cores in West Branch field from Curran (1990). These cores were selectively studied to sample each of the seven depositional facies and to evaluate reservoir characteristics from field to pore scale in order to assess enhanced oil recovery (EOR) potential in the Dundee Limestone in the Michigan Basin. Cores that covered the Dundee limestone interval and part ofthe Roger City were present in

Isabella, Midland, Gladwin, and Ogemaw Counties. All cores are located in the east- 23 central part of the Michigan Basin (Figure 1) and were examined and described thoroughly using a binocular microscope and hand lens. Core photographs were taken after the core was polished to improve clarity and maximize the observation and documentation of depositional features and rock fabric. The core photographs are located in Appendix C.

Detailed observation of lithology, fossil content, cement type, pore types and distribution, and primary sedimentary structure were conducted to document the vertical lithologic succession, define distinct Dundee depositional facies, and develop depositional environment interpretation and geological control on reservoirquality for

Dundee Limestone. The lithofacies distribution and pore geometry were described using Dunham (1962) and Embry and Klovan (1971) classification for the depositional facies and Choquette and Pray (1970) for porosity classifications (Table 3, Figure 10). Some wells have good subsurface data quality (core, core analysis, wire-line logs) but lack modern wire-line logs or were missing key cored intervals.

The most notable wells that had all ofthe required data are located in Mount Pleasant, North Buckeye, and South Buckeye and West Branch fields. Additionally, because of lost core interval, an interpretation of some but not all cored depth normalized to the depths used in the wire-line logs. When the shifted depths (i.e., between the core data and the wire-line logs) are used, the position ofa described or analyzed length ofcore can be referenced directly to match the wire-line logs (Appendix B).

Petrographic Analyses

During a preliminary study of each core, samples were cut for petrographic thin-sections analysis. Prior to detailed description of a core, it is desirable to have at least a preliminarydescription ofeach sample in thin-section in order to identify grain

24 types and diagenetic fabrics accurately. Sixty thin-sections were made from selected facies and supplemented with preexisting thin-section in the collection at the MGRRE core lab. The thin-sections were impregnated with blue epoxy to highlight porosity, and some thin-sections were partially stained with alizarin red and potassium ferricyanide stain. Alizarin red stain allows for the discriminating between calcite and dolomite. It has been noted by Tucker (2001) that Alizarin red stain changes non- ferroan calcite to pink while non-ferroan dolomite remains unstained. The potassium ferricyanide stain has a high sensitivity for ferrous iron, which allows for the rapid identification of ferroan calcite and ferroan dolomite in carbonate rocks. Hatzman

(1999) stated that the ferroan calcite stains pale to deep blue and ferroan dolomite stains a turquoise color with potassium ferricyanide. Thin-sections were examined and photographed for detailed analysis using a Leica DC Camera petrographic microscope. Petrographic analysis of thin-sections yielded qualitative petrophysical characterization to identify primary depositional and diagenetic processes in order to determine the geological controls on reservoir quality and pore geometry. Thin- section data was compiled with wire-line log derived porosity and the conventional core analysis data in order to make a comprehensive data set of reservoir quality attributes.

25 Table 2. Cores used in this study.

Permit Well Name Field County Production Total Field Production # Name

19693 McNerney, B Wise Isabella Dry Hole 4.2 MMbbl. Through E3 2010

39770 Mt Pleasant Mt Isabella Oil 30.4 MMbbl. Through Unit Tract 55 Pleasant 2010

39771 Mt Pleasant Mt Isabella Oil 30.4 MMbbl. Through Unit Tract 46 Pleasant 2010

36367 McClintic-3 Mt Isabella Oil 30.4 MMbbl. Through Pleasant 2010

36387 Miller, Viola Mt Isabella Oil 30.4 MMbbl. Through 1 Pleasant 2010

35461 Sierra Land Mt Midland Oil 30.4 MMbbl. Through CO., INC 1, Pleasant 2010

35764 Ames, C W 1 Mt Midland Oil 30.4 MMbbl. Through Pleasant 2010

36227 Sokolowski, Mt Midland Oil 30.4 MMbbl. Through CT1 Pleasant 2010

36259 Pfund-1 Mt Midland Oil 30.4 MMbbl. Through Pleasant 2010

32780 State North Gladwin Oil 21.5 MMbbl. Through Buckeye B-6 Buckeye 2011

52002 Salla, John 9- North Gladwin Oil 21.5 MMbbl. Through 11 HD Buckeye 2011

43383 Nusbaum South Gladwin Oil 7.5 MMbbl. Through Kern 3-W, Buckeye 2010

36730 Fitzwater #6- South Gladwin Oil 7.5 MMbbl. Through 26 Buckeye 2010

35720 Huston 1-2 Butman Gladwin Oil 39 Mbbl. Through 2001 mostly from Lucas Fm

28399 Grow 4 West Ogemaw Oil 14.2 MMbbl Through Branch 2011

26 Conventional Core Analyses

Conventional whole core analyses (porosity and permeability data) were

originally obtained from core measurements by the operators prior to the initiation of

this study. The data from conventional whole core analyses were obtained from

MGRRE core lab at Western Michigan University, which includes footage analyzed,

horizontal and vertical permeability values, porosity value, fluid saturations (i.e., oil

and water), bulk density, grain density, and oil and gas production probability.

Twenty-one wells were identified that have full diameter whole core analysis from the

six Dundee oil fields utilized in this study (Appendix D). In addition, an evaluation of

the conventional core analyses was conducted to establish porosity and permeability

relationships within facies throughout the six Dundee fields. Porosity and

permeability data from whole core analysis was converted to digital log curves and

then imported to PETRA to calibrate it with wire-line log derived porosity. These data

were used to produce cross-sections in order to fully characterize Dundee Limestone

reservoir types in the Michigan Basin.

Wire-line Logs

Generally, wire-line logs respond to petrophysical properties and not to textural and fabric depositional properties. Wire-line logs, for instance, may not be

used to differentiate between grainstone and wackestone or between grain types.

However, wire-line logs can distinguish different rock types based on the bulk

densities/porosity (Lucia, 1999).

More than 1500 wells were identified in the study area, from which 381 (old

and modern wire line logs) were used and digitized during this study using PETRA

software. Fifty wells have useful lithology log data, including gamma ray (GR), 27 neutron porosity (NPHI), bulk density (RHOB) and photoelectric factor (PEF) log

tracks. A few dual lateralog and dual induction resistivity logs (DLL) were also

available. The digitized interval typically extends from the base of the Bell Shale to

the base ofthe Lucas Formation.

Vertical successions of lithofacies and geologic fabrics obtained from core

descriptions were calibrated with wire-line log response to expand the spatial

coverage of the data. The modern digital logs were used to infer the reservoir

properties and to produce cross-sections and core to log correlations in the subsurface.

These cross-sections provide enhanced understanding of the lateral continuity and

facies distribution ofthe Dundee reservoir rock types.

Carbonate Classification Schemes

The carbonate classification scheme used in this research is the commonly

used Dunham (1962) and Embry and Klovan's (1971) classification scheme. These

schemes focus on the depositional fabric of carbonate rocks. These schemes divide

limestones on the basis of their texture and mud vs. grain support (Table 3). Generic names (i.e. mudstone, wackestone, and grainstone) are modified with grain type such as skeletal wackestone or peloidal grainstone (Embry and Klovan, 1971)

Porosity types in carbonate rocks take a wide variety of forms. The most widely used porosity classification scheme was proposed by Choquette and Pray

(1970). They divided the porosity types in limestone into three groups. The fabric selective types contain pores defined by fabric elements of the rocks such as grains or crystals. The non-fabric selective types cross cut the primary fabric ofthe rock such as fracture and channel porosities. The third group may or may not show a fabric control

(Tucker and Wright, 1990). Porosity in this classification is based on both depositional

28 and diagenetic processes (Figure 10). The depositional environments of the studied rocks in this project are compared with the ideal standard carbonate facies of Wilson

(1975) and microfacies ofFlugel (1982, 2004).

Table 3. Dunham classification ofcarbonate rocks (Modified from Dunham, 1962).

DEPOSITIONAL TEXTURE RECOGNIZABLE DEPOSITIONAL 1EX1URL Original Components Not Bound Original Not Together During Deposition Components RECOGNIZABLE Contains Mud Lacks Bound mud Together Mud-supported Grain- and is During supported grain- Deposition Crystalline < 10% > 10% Supported grains grains carbonate (subdivisions Wacke Mud- Packstone Grain Boundstone based on texture stone stone stone or diagenesis)

FABRIC SELECTIVE NOT FABRIC SELECTIVE

Interparticle m Fracture 3 Vug Intraparticle

Channel Cavern ^^ Intercrystal El . > t. j

Moldic FABRIC SELECTIVE OR NOT

i—._ Fenestral Breccia Burrow

•.^sJM^O Shelter [g*<»itfgft Shrinkage Growth [\fa2 Boring J f~ framework

Figure 10. Classification ofcarbonate pore types, (Choquette and Pray, 1970).

29 Summary ofthe Methods

During this research on Dundee carbonate reservoir characterization, technical methods have been used that integrate, core, whole core analysis, and wire-line log data, obtained from MGRRE at Western Michigan University. Core data provide information on various depositional and diagenetic controls on reservoir quality. The description of facies and geologic fabrics from core material and whole core analyses

(porosity and permeability) was used to address enhanced hydrocarbon recovery and methods for locating volumes of unswept oil in Dundee reservoirs during waterflood and CO2 Enhanced Oil Recovery.

Petrographic analysis of thin-sections using mineral staining, allows for the rapid identification of various carbonate mineral species including calcite vs. dolomite and ferroan calcite vs. ferroan dolomite. Petrographic analyses of thin-sections was critical to initial identification of primary depositional and diagenetic textures, structures and mineral components in order to infer geological controls on reservoir quality and pore geometry.

Modern wire-line logs were tied to lithofacies obtained from core description and thin-section data in order to expand data coverage and make a comprehensive data set. Conceivably, this correlation provides diagnostic log facies which generally correspond to the lithofacies identified from core. The spatial distribution and geometry of reservoir facies along with lithofacies characteristics are used to predict reservoir quality and reservoir continuity issues, which in turn supports implementation of more effective waterflood or CO2 EOR in diverse Dundee oil fields in the Michigan Basin.

The availability of core in the Dundee Limestone in Michigan is limited in stratigraphic coverage and the spatial distribution. Some of the cored wells lack

30 modern wire-line logs, whole core analysis, and contain missing footages. These factors limit the spatial resolution and increase the uncertainty of the interpretation of the reservoir quality and geometry. Core only provides one dimensional data, therefore inter-well correlation using well logs may aid in determining the lateral continuity of the reservoir facies across the Dundee oil fields. However, due to these data limitations, the lithofacies that were characterized from cores were tied to the wire-line logs and some limited whole core analyses in order to identify reservoir- prone facies and predict their distribution in wells lacking core.

31 CHAPTER IV

SEDIMENTOLOGY

Depositional Facies

Primary depositional facies were defined based on examination of fifteen

cores from the Dundee Limestone in six central Michigan Basin oil fields. These

fields include Mt Pleasant, Wise, Butman, West Branch, North Buckeye, and South

Buckeye fields. The study of facies is most valuable in the context of establishing the

facies associations, interpreting depositional environments, and evaluating the

geological controls on reservoir quality for better evaluating the most prospective

EOR targets in Dundee Limestone reservoirs. Although this study focuses primarily

on the Dundee Limestone, the Rogers City limestone was described throughout the

six fields.

Primary depositional facies identified in this study are chiefly distinguished by

their distinct lithological characteristic, primary sedimentary structures, and fossils

contents using Dunham (1962) and Embry and Klovan (1971) classification schemes

for depositional fabric of carbonate rocks. Pore types and pore distribution are

described using Choquette and Pray classification (1970) for carbonate pore types.

Porosity of carbonate rocks is crucial in understanding diagenetic processes and

critical in identifying reservoir facies.

This analysis resulted in the definition of seven unique facies from

approximately 1100 feet (335 m) in fifteen cores throughout the six fields in the

central Michigan Basin. Three of these depositional facies represent reservoir facies

(facies #3, 5, and 7) because of their higher porosity and permeability values, and oil

saturation (observed on core) relative to non-reservoir facies (Facies #1, 2, 4, and 6).

Typically, all facies recognized in this study were deposited on a shallow carbonate 32 ramp setting deepening eastwards in the Michigan Basin (Gardner 1974; Curran and

Hurly 1992). The Rogers City and Dundee facies are interpreted to represent one or more marine depositional facies including open marine, protected shallow marine,

shoal, reef flank, patch reef, lagoon, and peritidal deposits.

Facies 1: Crinoidal skeletal wackestone (open marine)

Crinoidal skeletal wackestone is the only facies recognized from the Rogers

City. Facies 1 constitutes approximately 16 % of the gross thickness of the fifteen studied cores examined throughout the study area (Appendix B). This facies is a uniformly facies in the Rogers City Limestone. Common skeletal components include crinoids, gastropods, brachiopods, ostracods, trilobites, and forams. This facies is occasionally interbedded with thin crinoidal packstone beds that range in thickness from a centimeter to several centimeters, and also contains mud- rich nodular texture generally of centimeter scale with rounded to elliptical outlines (i.e. Mt Pleasant Unit

Tract 55 and McNerney, B E3 wells, Figure 11). Low amplitude stylolites occur within sediment packages and at package boundaries. The nodular fabric is often enhanced by pressure solution, with stylolite sutures surrounding the nodular grains

(Figure 11).

The crinoidal skeletal wackestone facies is characterized as a very dense, low porosity and permeability rock type that is an effective impermeable seal for the most

Dundee Limestone reservoirs. Limited whole core analysis for this facies indicates an average porosity of 1 % and average permeability of0.2md (Figure 12).

Interpretation: Crinoidal skeletal wackestone facies in the Rogers City was deposited during a marine transgression period, which places deeper marine Rogers

City on top of the shallow marine Dundee Limestone (Curran and Hurly, 1992). The

33 most common textures observed in this facies are wackestone and mud-rich packstone, which indicates low depositional energy conditions. This type of facies indicates a low energy, open marine with normal salinity environment of deposition

(Scoffin, 1987). The composition of crinoid stems, bivalve, and gastropods fauna

(Flugel, 2004) suggests that the depositional environment was a low energy, well oxygenated open marine. In core, the transition from shallow marine Dundee limestone facies to open marine Rogers City facies is abrupt in most examples. This facies has a sharp stylolitic contact (Figure 11) ofthe open marine Rogers City above shallow carbonate facies ofthe Dundee Limestone.

MT Pleasant Unit tract 55, 3573' llMT Pleasant I

Sty ' . : . I m '

0.1 mm

Figure 11. Crinoidal skeletal wackestone facies. (A) Core photograph, mud nodular texture (Nod) ranging from 1-2 cm in diameter. (B) Slabbed core photograph showing the contact between the upper Rogers City (RGRC) and the lower Dundee Limestone (DUND), separated by mineralized stylolite (Sty). (C) Thin-section photomicrograph, showing stylolites in low amplitude and crinoids-rich (Cri).

34 ♦ Crinoidal Skeletal Wackestone

2 4 Porosity {%)

Figure 12. Cross plot ofporosity and permeability measurements from whole core analyses ofcrinoidal skeletal wackestone facies. Large triangle shows average.

Facies 2: Bioturbated peloidal grainstone/packstone (shallow protected marine)

The bioturbated peloidal grainstone/packstone facies was cored in Nusbaum

Kern 3-W, Fitzwater 6-26, State Buckeye B-6, and Grow 4 wells. Facies 2 constitutes

approximately 6 % of the gross thickness of the fifteen studied cores examined throughout the study area. This facies is interpreted as a non-reservoir facies due to

its low porosity and permeability. Facies 2 is observed at the top of the Dundee just

below the Rogers City contact and it is also observed on or just below the

stromatoporoid boundstone facies, separating it from the crinoidal grainstone facies

(Appendix B).

Peloids are observed as major components of this facies, which comprise of up to 90% of the rock material (Figure 13). It is commonly very fine to fine-grained and moderately sorted. The common subordinate constituents within this facies

35 include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the peloidal grainstone/packstone facies, and they are typically filled with peloid grains. This facies is occasionally found in association with crinoidal grainstone facies (Figure

14).

The major porosity types include interparticle, intraparticle, limited vuggy, moldic, and intercrystalline porosity. Porosity value in range from 0.4% to 10%, with average porosity of 4%, and permeability ranging from 0.1md to 29md, with an average of 1.8md from whole core analyses (Figure 15).

Interpretation: This facies is interpreted as a protected marine environment.

Peloids are very common in shallow marine to more protected or tidal flat settings, where most peloids are preserved (Wilson, 1975; Scholle and Ulmer-Scholle, 2003).

In this facies micrite envelopes were observed on most of the bivalve fragments as result of endolithic algae. Micritic coatings formed by microbes are common in shallow ramp environments (Flugel, 2004). This facies shows no signs of physical compaction because borrows and peloids are well preserved and more likely a function of early cementation of peloids making them hardened. That is a result of substantial synsedimentary lithification of peloid grains followed by early calcite cementation ofthe rock, which prevented compaction ofpeloid grains.

36 Figure 13. Bioturbated peloidal grainstone/packstone. (A) Core photograph, showing the burrow (Bur). (B) Thin-section photomicrograph, note the uniformly small particle size and consistent shape ofpeloid grains (Pel) with sparry calcite cement throughout.

|Fitzwater# 6-26, 3592' | JNusbaum Kern 3-W, 3578'

[_M

i ("SHflflH^HE

Figure 14. (A) Slabbed core illustrating the crinoidal grainstone tempestites (outlined in blue) interbedded with burrowed skeletal peloidal grainstone facies. (B) Core photograph, note the burrow structure (Bur) is surrounded by crinoids-rich debris (Cri D).

37 ♦ Burrowed Peloidal Grainstone/Packstone 100

♦ ♦ £ 10 ♦ ♦

CO

Q. oo o

0.1 ♦ ♦- —1 r~ 6 8 10 12 14 16 Porosity (%)

Figure 15. Cross plot ofporosity and permeability measurements from whole core analyses ofburrowed peloidal grainstone/packstone facies. Large triangle represents average.

Facies 3: Crinoidal grainstone (shoal)

The crinoidal grainstone facies was cored in South Buckeye and West Branch

Fields. Facies 4 constitutes approximately 8 % of the gross thickness of the fifteen cores examined throughout the study area. In the South Buckeye Field this facies occurs as thin (1-2 ft) interbeds with the stromatoproid boundstone facies but is found as thicker (5-9 ft) beds in the Nusbaum Kern 3-W and Fitzwater #6-26 well.

However, the crinoidal grainstone facies does occur as significant thick separate units in Grow # 4 well, West Branch Field with a thickness of25 feet (7.6m) (Appendix B).

This facies is characterized by moderate to well sorted, fine to medium grained carbonate sand. Facies 3 is primarily made up of fine grained crinoid ossicles

(Figure 16) with average of 0.1-0.2 mm in diameter and can comprise up to 80% of

38 the rock material. Other skeletal constituents within this facies include brachiopods, bryozoans, rugose coral and some scattered peloids. Pressure solution associated with this facies results in low amplitude swarm stylolites both within sediment packages and at package boundaries. Major porosity types of this facies include interparticle, intraparticle, and limited vuggy and moldic porosity. Porosity ranges in this reservoir facies from 2% to 12%o, with average porosity of 7%, and permeability ranging from 0.1 md to 189md, with an average of 14md from whole core analyses (Figure 17). This facies is the primary reservoir facies in West Branch Field and a secondary reservoir facies in the

South Buckeye Field.

Interpretation: The crinoidal grainstone facies is interpreted to be deposited in an inner to middle ramp setting (Figure 36), very high energy shoal, above fair weather base. Well to moderately sorted grains are common in middle carbonate ramp and lagoonal patch reef settings (Flugel, 2004), controlled by high energy conditions, resulting from wave action and/or other shallow water currents. The wave action winnowed out mud leaving well sorted grains, which suggests a shoal environment. Sediment deposition and reworking probably occurred in shallow water depths ranging from near sea level to 20 feet (6 m) below sea level. The major accumulations ofthe grainstone occur surrounding the reef facies (i.e. South Buckeye

Field) or are not associated with reefs (i.e. West Branch Field). Pressure solution is common in the form of stylolites throughout this facies due to chemical compaction.

Burial cement observed in this facies is intergranular calcite crystal as syntaxial rim cement on crinoid ossicles (Figure 16 and 33).

39 0.3 mm

Figure 16. Crinoidal grainstone facies. (A) Slabbed core photograph ofthe crinoidal grainstone facies. (B) Thin-section photomicrograph ofcrinoids-rich sediment (Cri) with sparry calcite cement, porosity is in blue, porosity type is interparticle porosity (BP). Note cleavage extends through crinoidal grains and syntaxial cement overgrowth indicating syntaxial overgrowth formation (Sc).

♦ Crinoidal Grainstone 1000

T? ioo ♦f E ! i E io A 03

0.1 -4—

10 12 14 16 Porosity (%)

Figure 17. Cross plot ofporosity and permeability measurements from whole core analyses ofcrinoidal grainstone facies. Large triangle represents average.

40 Facies 4: Coral-stromatoporoid rudstone (reef flank)

The coral-stromatoporoid rudstone to rudstone facies is commonly found in association with stromatoporoid boundstone facies, and probably forms a secondary reservoir (e.g., South Buckeye Field). This facies was observed in core from three wells, the Grow #4, Nusbaum Kern 3-W, and State Buckeye B-6. This facies generally occurs below the reservoir facies (Appendix B). Facies 4 constitutes approximately 4 % of the gross thickness of the fifteen studied cores examined throughout the study area.

The reef flank facies is characterized by poorly sorted, re-deposited accumulations of debris and chunks of crinoids, bryozoans, brachiopods, rugose and tabulate corals, and stromatoporoid fragments that were deposited in grain-rich matrix

(Figure 18). Porosity within this facies is predominantly intraparticle and interparticle with a minor distribution of intercrystalline and moldic porosity. Variable porosity ranges

in this facies from 1% to 8%, with average porosity of 4%, and low to moderate permeability ranging from 0.1 md to 5.4md, with an average of 0.6md from whole core analyses (Figure19). Interpretation: This facies is interpreted as a reef flank environment. The flank deposits, evident in cores Grow #4, Nusbaum Kern 3-W, and State Buckeye B-

6, contain abundant fragments, mostly of corals and stromatoporoid that were ultimately derived from the stromatoporoid boundstone facies (facies # 5). This facies was deposited in high to moderate energy. The reef flank facies typically developed around the reefs in a circular pattern (Flugel, 2004). The reef flank with characteristic partial to complete winnowing of mud, poorly sorted sediment, and angular to sub-

41 angular skeletal orientation indicate a high energy environment of deposition,

associated with waves and the erosion ofreef builders.

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Figure 18. Reef flank facies. (A) Core photograph, showing the ripped up and re- deposited stromatoporoids (Strom), crinoids (Cri), and bryozoans (Bry) on a reefflank. (B) Thin section photomicrograph ofreefflank deposit, porosity in blue, interparticle porosity (BP). Note dominant skeletal grains are crinoids (Cri), ostracods (Ost), and brachiopods (Brc) with sparry calcite cement throughout.

oCoral-Stromatoporoid Floatstone 100

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Figure 19. Cross plot ofporosity and permeability measurements from whole core analyses ofreef flank facies. Large triangle represents average.

42 Facies 5: Stromatoporoid boundstone (patch reef)

The stromatoporoid boundstone facies represents the most important

hydrocarbon producing facies in the South Buckeye Field (Gladwin County). Facies 5

constitutes approximately 7% of the gross thickness of the fifteen studied cores

examined throughout the study area. This facies is present in most studied core,

Fitzwater #6-26, Nusbaum Kern 3-W, Huston 1-2, and State Buckeye B-6. The core data from this facies shows that the stromatoporoid patch reef is up to 23 feet (7 m) thick (Appendix B). This facies is commonly found in association with shoal and reef

flank facies.

The patch reef facies consists primarily of massive stromatoporoids, and tabular and fragmental corals, brachiopods, crinoids, bryozoans, and trilobites. The boundaries of the stromatoporoid facies have common sharp and stylolitic or less common gradational contact with other facies. The stromatoporoids contain pillar and lamina structures (Figure 20). The folds or undulations are common in these knobby to bulbous, encrusting forms. Such stromatoporoids are common encrusters of other organisms and are thus major contributors to the binding of reef constituents as well as the generation of framework structure during deposition ofthis facies (Scholle and

Ulmer-Scholle, 2003).

Porosity in facies 5 includes growth framework, vuggy, and interparticle and also intraparticle porosity. Variable porosity ranges in this reservoir facies from 1% to

16%), with average porosity of 7%>, and permeability ranging from 0.1md to 944md, with an average of 123md from whole core analyses (Figure 21). The stromatoporoid facies forms a primary reservoir in the South Buckeye and Butman fields.

Interpretation: the stromatoporoid boundstone facies 5 (Figure 36) is interpreted to have been deposited in a patch reef environment. Stromatoproid reefs

43 • are dominate faunal components in Paleozoic reefs and formed exclusively on

platform margins or platform interior in shallow, warm, well-oxygenated

environments (Flugel, 2004). Growth of patch reef generally indicates shallow-water

deposits of 60 feet or less (James, 1983), where wave energy and water circulation

provide clear-water conditions favored for reef development. Stromatoporoids also

occupied a wide range of reef associated environments, varying from high to

moderate energy environments (Flugel, 2004). The patch reefs in the study area were

stabilized by the massive stromatoproid and tabulate coral growth, and these reefs

probably grew to wave base. The pillars and laminae structure of stromatoporoids are well preserved, which implies an originally calcite mineralogy (Scholle and Ulmer-

Scholle, 2003). The open galleries of the stromatoporoids and the spaces between latilaminae are partially occluded with calcite cements although many ofthe chambers are open pore space (Figure 20). Chemical compaction is very common in the form of

stylolites throughout this facies.

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Figure 20. Patch reeffacies. (A) Core photograph ofstromatoporoid boundstone showing pillar and lamina structure (yellow arrows). (B) Thin-section photomicrograph, porosity is in blue, intraparticle porosity is dominant.

44 Note some ofthe intraparticle pores are partially filled with calcite cements, but most ofthe galleries are open pore spaces.

♦ Stromatoporoid. 10000

1000 E •Ooo O £» 100 o JQ p <$ o o o

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Figure 21. Cross plot ofporosity and permeability measurements from whole core analyses ofstromatoporoid boundstone facies. Large triangle is average.

Facies 6: Skeletal wackestone (lagoon)

The skeletal wackestone facies forms approximately 17% of the gross thickness of the fifteen studied cores examined throughout the study area (Appendix

B). This facies is found within repeated shallowing upward sequences with cycles consisting of subtidal lagoonal wackestones grading upward to packstones and grainstones facies. The skeletal wackestone facies is in sharp stylolitic contact with the fenestral, peloidal grainstone/packstone facies (facies 7) when present in studied cores (Figure 22).

The common allochems in this facies include gastropods, ostracods, bivalves, trilobites, brachiopods, bryozoans, coral, and with minor stromatoporoid debris present in a few places. These skeletal grains are scattered in carbonate mud (Figure

45 23). Minor intercalations of peloidal skeletal grainstone and wackestone are

occasionally associated with this facies in beds less than a foot thick when present.

Pressure solution ofcarbonate results in abundant wispy stylolitization.

The porosity types within this facies are vuggy and moldic with limited fracture porosity. Porosity value ranges from 0.5%> to 10%, with average porosity of

4%, and permeability ranging from 0.0 lmd to 135md, with an average of 2md from whole core analyses (Figure 24). This facies is interpreted as a non-reservoir facies due to its generally low porosity and permeability value.

Interpretation: The skeletal wackestone facies was formed in a lagoonal depositional environment of an inner ramp setting (Figure 36), low-energy with open water circulation at or just below the fair weather wave base (Flugel, 2004). Limited distribution of skeletal grains, lack of bioturbation and a muddy matrix suggest a low energy environment ofdeposition.

There is little cement observed in this facies due to limited distribution of primary porosity available for cementation. Other factors that affected this facies are the dissolution of some calcite crystals and skeletal fragments to form vuggy and moldic porosity. The minor primary porosity associated with coral and stromatoporoid fragments, is commonly filled with calcite cement. However, the secondary dissolution enhancement of porosity is pronounced in few places by the presence of small amount of moldic porosity that occurs after mollusks shells (Figure

29). Fractures and stylolitization (large and swarm sutured styolites) are common in this facies. Styolites result in increased permeability by connecting the isolated vugy porosity in this facies (Figure 34). A sharp stylolitic contact of the skeletal wackestone facies with the peritidal facies (facies #7) coincides with rapid fluctuation in sea level.

46 Figure 22. Slabbed core showing a sharp stylolitic contact between the fenestral peloidal grainstone/packstone facies and skeletal wackestone facies. The white arrow indicating the "up" direction in the core.

Figure 23. Skeletal wackestone facies. (A) Core photograph ofskeletal wackestone facies associated with stylolites (Sty) and fractures (Fr). (B) Thin-section photomicrograph, porosity is in blue, dominant moldic porosity (Mo), skeletal grains include gastropods (Gsp) and ostracod fragments. Note the low-amplitude suture stylolites (Sty) and oil stain (Oil S).

47 o Skeletal Wackestone 100

Figure 24. Cross plot of porosity and permeability measurements from whole core analyses ofskeletal wackestone facies. Large triangle represents average.

Facies 7: Fenestral peloidal grainstone/packstone (peritidal)

The fenestral peloidal grainstone/packstone facies has produced the most oil and gas from Dundee limestone reservoirs. It is observed in North Buckeye, Mt Pleasant, and Wise Fields, which forms approximately 42%> of the gross thickness of the fifteen studied cores examined throughout the study area (Appendix B). This facies is commonly the upper most Dundee Limestone unit and is capped by more open marine Rogers City facies when present. The geometry of this facies is typically laterally extensive on a field scale. The fenestral reservoir unit is composed of several shallowing upward, high-frequency cycles consisting of a lower skeletal wackestone and an upper fenestral grain-dominated grainstoneand packstone facies.

Facies 7 is buff to tan limestone with solution enhanced fenestral pores (commonly ranging from 0.1-6mm long and 0.01-2mm wide). This facies is largely

48 made up of peloids, which can comprise up to 90% of the rock material. The peloids are fine grained carbonate sand (generally less than 0.2 mm in size), moderately sorted and spherical to subspherical-shaped and with uniform size. Skeletal grains within this facies include brachiopods, bivalves, ostracods, gastropods, crinoids, corals, and stromatoporoids debris. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure (Figure

25).

Porosity within this facies is dominantly fenestral, interparticle and intraparticle with minor fracture porosity. Variable porosity ranges in this reservoir facies from 1% to 14%, with average porosity of 9%, and permeability ranging from

0.1md to 5200md, with an average of 195md from whole core analyses (Figure 26).

Interpretation: Facies 7 was formed in a peritidal depositional environment in an inner ramp setting (Figure 36). Shallow platform interior areas are typically composed of protected shallow marine environments with moderate circulation.

Peloids commonly occurred in shallow marine subtidal and tidal flat settings as thick graded laminae with fenestral fabric (Wilson, 1975). These tidal flat facies typically occur as stacked cycles, each ideally containing internal shallowing upward succession (Flugel, 2004). The formation of fenestral pores is a result of gas production associated with the decay of organic material and the lateral migration of water and/or gas, all occurring within peritidal environments (Shinn, 1983a). The cyanobacteria laminations, buff color and the blocky calcite cement are notable and observed in the Dundee Limestone peritidal facies. The presence of these features in facies 7 indicates that the deposits were likely formed in a peritidal environment that was intermittently exposed above sea level. The fenestral voids in facies 7 were filled by fine grained micritic internal sediment and the remnant pore spaces within the

49 fenestrae were filled with sparry calcite cement (Figure 27) a further indication of peritidal deposition. Such internal sediments present in the fenestral voids suggest that this deposit was formed in peritidal environment and was subaerially exposed

(Scholle and Ulmer-Scholle, 2003). The allochemical components of this facies are cemented by calcite crystals and some pores were completely occluded by blocky calcite cement. When the fenestral voids are unfilled, fenestrae may enhance porosity and permeability when partly connected. Shinn (1968) suggests that the peritidal sediments resist compaction due to syndepositional cementation. The allochems in this facies show few signs of physical compaction, whereas pressure solution is very common in the form ofstylolites.

Mt Pleasant Unit Tract 55, 3594'

TFL •__ Syb I

hi

Figure 25. Fenestral peloidal grainstone/packstone facies . (A) The core photograph displays an irregular tidal flat lamination (TFL), cyanobacterial mats (Syb), and fenestral structure (Fs). (B) Thin-section photomicrograph, porosity is in blue color, note fenestral fabric with irregular fenestrae (Fs) in relatively fine peloids grains (Pel). These fenestrae are partly filled with calcite cements (CC) and some ofthem are completely occluded in this peloidal peritidal deposit.

50 ♦ Fenestral Peloidal Grainstone/Packstone 10000

^ 1000 •a E 7* 100

JQ S 10 E c 0) Q. i --

o.i

6 8 10 16 Porosity (%)

Figure 26. Cross plot ofporosity and permeability measurements from whole core analysis offenestral, peloidal grainstone/packstone facies. Large triangle represents average.

MtPleasant Unit Tract 55, 3575' |

•'fa i

P§ { B8?5

Figure 27. The thin-section photomicrograph showing an example of fenestral vugs filled by fine grained micritic internal sediment (red arrow) and the remnant pore spaces within the fenestrae filled with sparry calcite (yellow arrow). 51 Diagenesis

Introduction

The diagenesis of carbonates encompasses any physical and chemical alterations that affect sediments after deposition until the realms of incipient metamorphism (Tucker and Wright, 1990). Diagenesis often starts at the sea floor

(syngenetic or eogenetic alteration), continues through deep burial (mesogenetic alteration), and extends to subsequent uplift (telogenetic alteration) (Scholle and

Ulmer-Scholle, 2003). Most carbonates are deposited and start their diagenetic history in the marine phreatic zone (Longman, 1980).

Diagenesis includes not only distinct processes such as cementation that form limestones and dissolution which produces caves, but also includes subtle processes such as the formation of micro-porosity and changes in trace elements content

(Tucker and Wright, 1990). Furthermore, diagenetic processes can enhance, create and/or destroy porosity in carbonate rocks. As depth increases, there is a general decrease in porosity; however, there are late processes of dissolution and fractures that can enhance porosity. Diagenetic processes affecting carbonate sediments and rocks are micritization, dissolution and cementation, compaction, neomorphism, dolomitization, and replacement ofcarbonates by non-carbonates (Flugel, 2004).

Marine carbonates consist of a mixture of aragonite, high-magnesium (Mg) calcite and low-Mg calcite. Aragonite and high-Mg calcite are common in recent carbonates and are metastable because they transform to calcite with time. Low-Mg calcite is the most stable form of CaC03 and deposited from meteoric water (Tucker and Wright, 1990).

52 Diagenetic alterations in the Dundee Limestone

A study of the diagenetic evolution of Dundee Limestone reservoirs in the

Michigan Basin was undertaken to better understand the controls on reservoir quality.

Core and petrographic analyses of the Dundee Limestone indicate that the original

fabric of most carbonate rocks has been altered by diagenetic processes. The major

syndepositional and diagenetic processes affecting the Dundee carbonate reservoirs

are microbial micritization, dissolution-cementation, burrowing, and physical and

chemical compaction. The most common diagenetic feature present in the Dundee

Limestone is pressure solution and stylolitization.

Microbial Micritization

This is a process whereby the bioclastics and other particles are altered by endolithic algae, fungi and bacteria while on or just below the sea floor (Tucker and

Wright, 1990). Microbial micritization and micrite envelops formed around many of the skeletal grains in grainstones and packstones (Bathurst, 1975). These envelopes were created through the alteration of grains rather than precipitation of a new rind around the grain. Algae, fungi, or bacteria bore into the grain, die, and the subsequent alteration of the organic material provides a chemical environment conducive to calcium carbonate precipitation during the filling ofthe voids (Bathurst, 1975; Tucker and Wright, 1990).

Evidence of micritization in the form of micrite envelopes and completely micritized grains are common in the bioturbated peloidal grainstone/packstone, crinoidal grainstones, and reef flank facies (facies 2, 3, and 4). The micrite envelope developed on echinoderm, trilobite, and brachiopod fragments, which were bored by 53 the action of endolithic algae. The pores are filled by surrounding micrite matrix

(Figure 28).

Figure 28. The micrite envelopes ofthe outer part ofthe shell are a result ofmicrobial microboring and infilling of the holes by micrite. (A) Note the micrite envelope surrounding the trilobite fragment (Yellow arrow). (B) Note a thin coating of micrite envelopes is evident around brachiopod fragments (yellow arrow).

Burrowing

Biological processes, such as burrowing activities, are most widespread in marine environments. Burrows are formed in relatively unconsolidated sediments by the activity of animals during feeding, resting or migration, and also make an important contribution to the structure of carbonate sediments. Burrowing and bioturbation are more common in inner and mid-ramp environments (Flugel, 2004) where biologic alteration of primary depositional fabric and grain reworking may determine the distribution ofporosity and permeability pathways.

In this study, evidence of pervasive bioturbation is very common in the peloidal grainstone/packstone facies (facies 2). Burrows are more recognizable (i.e.,

South Buckeye Field) due to the difference in color between burrow and surrounding

54 sediment (Figure 13). Many burrows are filled by medium to fine sand sized bioclast

fragments and peloids, which affected the porosity and permeability and adds

additional complexity to reservoir quality.

Dissolution-cementation

Dissolution-precipitation processes suggest diagenesis in the meteoric

environment (Wallace et al., 1991). Undersaturated meteoric water in pores will

dissolve carbonate grains, sediments, and cements. Dissolution is more effective in

shallow near surface meteoric environments, in deep burial, cold water, and in the

deep sea (Flugel, 2004), where seawater becomes undersaturated with respect to

aragonite and high Mg-calcite. Mixing zones of marine and non-marine waters is also

considered an important site ofmajor dissolution caused by mixing corrosion (Tucker

and Wright, 1990).

Dissolution and leaching of gastropod and some brachiopod fragments resulted in the development of many types of secondary porosity including moldic, intraparticle, and vuggy (Figure 29). The crinoidal grainstone and skeletal wackestone facies (facies 3 and 6) show areas where dissolutions has occurred and removed aragonitic skeletal grains. Meteoric dissolution also affects the crinoidal skeletal wackestone and reef flank facies (facies 1 and 4) where moldic and vuggy porosity is present.

The moldic, secondary porosity has been partially reduced through later cementation with blocky calcite crystal cement. In patch reef facies some of the intraparticle pores and the spaces between latilaminae are partially occluded with calcite cements but some of the chambers are open pore space (Figure 20). However, in North Buckeye Field, where the patch reef facies is not a primary reservoir due to

55 • its low porosity and permeability, the open framework of stromatoporoids is extensively occluded by calcite cements (Figure 30). One explanation for this contrast may be related to the timing and intensity of cementation. The most significant amount ofcementation occurs in patch reef environment with higher rates ofagitation and/or lower sedimentation rates (Flugel, 2004).

Figure 29. (A) An example ofpredominantly intraparticle porosity in crinoid stem and stromatoporoid (yellow arrow) (B) Crinoid fragments and other skeletal fragments, including mollusks, are dissolved leaving abundant moldic porosity (yellow arrow) in relatively fine grain matrix.

State Bucke

Figure 30. The open galleries of the stromatoporoids are extensively occluded by calcite cements (yellow arrows) in facies 3 ofthe North Buckeye Field. 56 The fenestral peloidal grainstone/packstone facies (facies 7) shows areas where most of fenestral porosity is well preserved suggesting that the fenestrae formed in an active diagenetic environment where early lithification is common

(Shinn, 1983b). Some of the voids are partially filled with blocky calcite spar cement or internal sediment (Figure 31), however, the effect ofthis process on the reservoir is relatively minor because ofthe large amount ofpreserved primary porosity.

Figure 31. Fenestral fabric in tidal flat facies showing fenestral porosity (Fs) in light blue that is larger than the associated peloidal texture. Note some of large pores either partially or fully filled with blocky calcite (BC), and some small pores are either partially or fully filled with sparry calcite crystals (yellow arrow). This is the main reservoir facies.

The most common types of calcite cement encountered in most studied facies are calcite crystals and blocky calcite cement. These cement types may indicate diagenesis in meteoric regime (Longman, 1980). Calcite crystals replace mollusk

57 fragments (Figure 32) and line pore spaces (Figure 32). Calcite crystals range in size from 0.1 to 0.3mm. All porous facies described here, contain some blocky and calcite crystal cement. Further, most of the interparticle pore space is lost to cementation by varying amounts of calcite crystal and blocky calcite cement rather than compaction suggesting relatively early diagenetic cementation, consistent with early meteoric processes.

Other observed cements are represented by syntaxial calcite overgrowth cement. This type of cement is encountered most communally around the echinoderm debris (Bathurst, 1975), which will be discussed in greater detail in the following.

Figure 32. Example of meteorically leached mollusk shells resulting in moldic porosity in the crinoidal grainstone facies. This moldic secondary porosity has been partially or fully occluded by calcite crystal and blocky calcite cement (yellow arrows).

Syntaxial overgrowth cement is widespread in wackestones, packstones, and grainstones. The origin of this cement on echinoderms is explained as a filling of

58 secondary pores produced by differential dissolution of carbonate mud in the vicinity ofechinoderms (Flugel, 2004). The presence of syntaxial overgrowth on echinoderms is common in the meteoric phreatic zone (Scholle and Ulmer-Scholle, 2003).

However, syntaxial overgrowths are rare in the meteoric vadose zone and deep burial environment (Longman, 1980). Syntaxial overgrowths were observed in crinoidal skeletal wackestone and crinoidal grainstone facies (facies land 3) where crinoid fragments are surrounded by syntaxial cement (Figure 33). In most cases, syntaxial overgrowth initiates on echinoderm framework grains partially occludes interparticle porosity (Figure 34).

Fwater # 6-26, 3624' —»• '•*"•; ^—~

Figure 33. The syntaxial overgrowth on crinoid ossicles (Cri) has reduced most of pre-existing interparticle porosity (yellow arrows).

59 Fractures and Stylolitization

Much burial diagenesis of non-cemented carbonate sediments under an overburden results in physical compaction, the reduction in porosity and grain fracture. Physical compaction is commonly followed by chemical compaction, which results in stylolites and solution seams formed under burial conditions (Flugel, 2004).

Physical compaction includes dewatering, grain reorientation and brittle or plastic grain deformation reducing porosity in many carbonate deposits (Scholle and Ulmer-

Scholle, 2003).

The physical compaction features observed in this study are fractures and shattering ofrelatively robust brachiopod shells. The fractures observed from core and thin-section examination include small-scale fractures ranging from 0.1-6cm (Figure

22 and 23a), and fractures associated with sutured stylolites (Figure 23a and 34 a), which generally occur in the open marine and lagoonal facies (facies land 6). Natural opening-mode fractures are observed and locally abundant in core. In some cases fractures have a wide range of sizes and most are filled with calcite cement. Some fractures remain open in the crinoidal grainstone facies (Figure 34b).

Chemical compaction in carbonate rocks results in dissolution and accumulation ofinsoluble residue along stylolite surfaces. Stylolitization, which is the predominate phenomenon of chemical compaction, occurres in all facies in the form of stylolites and solution seams. Stylolites in all facies are irregular, suture-like, and have high and low amplitude (Figure 35). Concentrations of insoluble residues occur along many suture grains contact (Figure 35). Microstylolites are common between skeletal grains and carbonate mud matrix, implying that pressure solution came after the matrix was lithified.

60 Figure 34. The presence of fractures (when unhealed with calcite cement) in many cases, can greatly increase the permeability of the rock. (A) A limestone with multiple fractures associated with stylolites are partially lined up with calcite cements (white arrows), and small fractures are completely filled with calcite cement (yellow arrows). (B) Note opening- mode fractures in crinoidal grainstone facies (yellow arrows).

[State Buckeye B-6, 3624' 1 Ki K—#k. -•**•*, ' V'

-•it •

-:;'JLjII^ **#'• 1 j

• *3 '

v*V-"---P^! 0.3mm

Figure 35. Thin-section photomicrograph oflarge amplitude stylolites typical ofmany pressure solutions in carbonate mud matrix. Note enrichment of dark insoluble materials along irregular stylolite, in which case stylolites can be recognized by change in texture ofthe rock (yellow arrows).

61 Depositional Environment Model

Carbonate Ramp

A carbonate ramp is very low gradient depositional slope from the shallow water shoreline or lagoon to the Basin floor, with usually less than one degree slope and has no slope break (Read, 1995). The carbonate ramp system contains tidal flat, lagoonal, and shoal facies (Tucker and Wright, 1990). Primarily the carbonate ramp facies are controlled by energy level (fair-weather wave base and storm wave base) and also are controlled by sea level fluctuation, which simply shift facies belts up and down the ramp (Flugel, 2004).

A conceptual model of the Middle Devonian Dundee Limestone is summarized in Figure 36. This model was constructed based on the interpretation and definition of depositional facies and their vertical stacking patterns derived from core analysis. The depositional environment interpretations of the study area indicate that the Dundee Limestone was deposited in an inner carbonate ramp setting while the

Rogers City was deposited in a mid carbonate ramp setting in the Michigan Basin.

The Rogers City and Dundee Limestone formations along this ramp consist of open marine, protected shallow marine, grainstone shoal, reef flank, patch reef, lagoonal, and peritidal environment of deposition. Development of a core-based depositional model of the Dundee is consistent with the carbonate ramp depositional models described by Tucker and Wright (1990) and Flugel (2004).

62 Inner Ramp

Middle Ramp

Outer Ramp

Protected shallow marine I BOpen marine

Figure 36. Depositional setting for the seven depositional facies of the Rogers City and Dundee Limestone. Sequence Stratigraphic Considerations

Although hydrocarbon exploration wells have been drilled in the Dundee

Formation of Michigan Basin since 1930s, there have been no published studies that focus on the sequence stratigraphy for the subsurface Dundee Formation. Additionally the correlation of stratigraphic sequences and exact duration and number of higher- frequency cycles in the Dundee Formation is not well documented due to lack of chronostratigraphic data, insufficient well penetration, and there is no definitive evidence of exposure surfaces in the Dundee interval. However in this study, a lithology-based depositional model and a logical approach to a sequence-stratigraphic framework interpretation will be introduced, which can be applied to a variety of depositional settings and hydrocarbon exploration and production practices.

Sequence stratigraphy uses geological response to relative sea level fluctuation in order to establish chronostratigraphic correlation. Shallow-water marine carbonate sedimentary systems are primarily affected by water depth. The depositional stratal patterns and facies distribution are strongly influenced by relative sea level changes and typically form in tectonically stable settings in intracratonic Basins and cratonic interior setting during global eustatic highstand (Sarg, 1988). Relative changes of sea level are controlled by the interplay of eustasy, local tectonics (uplift and subsidence), and sediment accumulation rates (Plint et al., 1992). Eustatic sea level fluctuations are largely controlled by changes in the volume of water in the ocean, or changes in global Basin dimensions influencing the volume of water contained or displaced

(Plint et al., 1992). Carbonate sediment production rates are water-depth dependant and are highest in shallow water, factors which make carbonate systems sensitive even to small amounts of subsidence and uplift (Sarg, 1988). The combination of

64 eustasy and tectonic subsidence results in change in relative sea level. The change of relative sea level provides the accommodation space for sedimentation.

Accommodation is reflected in the sedimentary record as hydrodynamic and biologic environmental indicators, each of which also serves as the basis for identifying depositional facies (Sarg, 1988 and Plint et al., 1992).

Sea level fluctuations have been subdivided on the basis oftime duration (Haq and Schutter, 2008). First-order cycles, range from 200 to 400 Ma, and are most likely caused by the break-up and formation of super-continents. Second-order cycles, vary between 10 and 100 Ma, and are produced by plate tectonics. The thickness of 2nd order cycles is commonly hundreds of meters (Read, 1995). The origin of third-order cycle (1-10 Ma), remains debatable, and in many cases it is not clear whether controls are tectonic activity or eustatic sea level changes or both (Strasser et al., 2000). The thickness of third-order cycles can be hundreds of meters (Read, 1995). Fourth-order cyclicity, ranges from 100 to 400 Ka, and may be caused by climatic changes. These cycles can attain thickness of tens of meters. Fifth-order cycles (20 to 40 Ka) can be produced by obliquity throughout ice house periods and precession during green house periods or autocyclic variations during deposition (Read, 1995).

Dundee Limestone sequence and cycle boundaries can be identified by abrupt facies shifts from shallow to relatively deeper water facies. Therefore, the idealized depositional facies stacking pattern presented in this study were determined on the basis of the observed vertical facies relationships in different facies areas/fields in order to understand the scales and geometries of the facies variability (Figure 37).

Based on the core examination the Rogers City and Dundee formation stacking patterns tend to be composed of one low frequency cycle (3rd order) and two to four

65 high frequency cycle (4th and 5th order, Figure 38). Sequence and cycle boundaries were specifically determined by identification of stacking pattern of different facies types from core data. These boundaries are picked at abrupt landward shift in facies

(i.e., when any deeper facies overlies a shallower one).

The overall facies patterns observed in the Dundee intervals is a succession of approximately 10 to 50 feet (3-15m) thick shoaling upward sequences (Figure 38).

This whole succession was then drowned by a return ofdeeper water deposition at the

Dundee and Rogers City boundary. These overall shallowing upward packages in different facies successions and dislocation of facies across stratal contacts may indicate rapid rates of relative sea level change including cyclicity of autocyclic origin. The change from deposition ofpatch reef to peritidal facies (facies 5 and 7) in

North Buckeye represents local shallowing of the environment. Cores from Wise and

Mt Pleasant fields, where the dislocation of lagoonal and peritidal facies (facies 6 and

7) are best observed across the stratal stacking pattern contacts, suggest that the shallower water environment are more sensitive to fluctuation in relative sea level.

The low frequency cycle (upper Dundee to Rogers City) exhibit a thickness of 65 to

130 feet (20 to 40 m). Higher frequency cycle (shoaling upward) exhibits a thickness of 10 to 50 feet (3 to 15 m), and the entire Dundee interval is approximately 230 feet

(70 m, Appendix B).

Recognition of transgressive and regressive cycles in the Middle Devonian

Dundee of the Michigan Basin has been suggested by Gardner (1974). The contact between the Rogers City and the Dundee formations observed on all studied cores, is the most significant dislocation of facies since this contact is interpreted as a major flooding surface that drowns the whole Dundee platform. This contact may coincide

66 with a portion of relative sea level curve proposed by Haq et al., 2008, which shows a large sea level regression and subsequent transgression at 390Ma. In this study this relative sea level event is interpreted as the Rogers City and Dundee contact (Figure

39).

The higher order cyclicity of the Middle Devonian Dundee Formation formed during overall regression, acted on a range of paleobathymetries, shallow in some places and progressively deeper elsewhere (e.g., shoal and lagoonal facies), locally complicated by active structural highs. In numerous examples, structurally controlled paleobathymetry localized peritidal, patch reef, and shoal facies accumulations in

Dundee carbonate rocks. For example, Mt Pleasant Field represents an inner ramp setting, but is located in a relatively Basin ward location of the eastward dipping,

Dundee carbonate ramp in the Michigan Basin. This shows local structural control on facies development. Other fields in the adjoining area ofGladwin County, also exhibit the development of shoal or reef reservoirs on structurally induced paleobathymetric highs (e.g., Butman, North and South Buckeye). Evidence is accumulating in the

Dundee Formation that tectonically controlled paleobathymetry is a major predictor of localized reservoir facies. Available data indicates a coincidence of current structurally high position with relatively positive paleobathymetry during Dundee deposition.

67 Idealized Vertical Succession of Seven Facies

Fenestral Peloidal Grainstone/Packstone (Peritidal)

Skeletal Wackestone (Lagoonal)

• F5 Stromatoporoid Boundstone (Patch reef) i F4 Coral-stromatoporoid floatstone to rudstone (Reef Flank) F3 Crinoidal Grainstone (Shoal)

Bioturbated Peloidal Grainstone/Packstone (Protected shallow marine) A ~fT Crinoidal/Skeletal Wackestone (Open marine)

Figure 37. Idealized vertical stacking patterns of seven facies seen within the cores examined in this study. The blue triangle represents the transgressive systems tract and the red triangle represents the highstand systems tract.

68 Permit # 32780 Permit # 36730

Figure 38. Stacking pattern in different facies areas/fields observed in the Rogers City and Dundee interval from six fields. The Dundee interval within the cores examined in this study has one low frequency cycle and two to three high frequency cycles. The blue triangle in the low frequency cycles column represents the transgressive systems tract and the red

69 triangle represents the highstand systems tract. These symbols represent shoaling and flooding events in high frequency column. NPHI = neutron porosity, RHOB = bulk density, perm = permeability.

< SEA LEVEL 5 STANDARD o ^5 CHANGES ONLAP CURVE c CO < >- USAGE landward Basinward 376 (?> 377 6(2) mm 380 380 8(1) FRASNIAN 382 0)

384(2) IB! 387 5(1) GIVETIAN SH 4(1) 390 MO (2) 391 3(1)

EIFELIAN 395 (2) 4(t)

* Kikwi Cei*rt#*ifc*d S+^tKvn

___

Figure 39. Changes in sea level recorded in the Middle Devonian deposits in Givetian stage, red star shows the proposed Rogers City and Dundee contact at approximately 390 Ma (Modified after Haq and Schutter, 2008).

70 CHAPTER V

GEOLOGIC RESERVOIR CHARACTERIZATION

Reservoir characterization of the in six Dundee oil fields includes the description of fifteen conventional cores (Table 2) and petrographic analysis.

Conventional core analyses for 21(Appendix D) wells and wire-line logs for 48 wells were also studied and compared to core material. Reservoir properties were delineated for different depositional facies observed in core compared to core analysis data. The core data were calibrated to the well-log patterns to predict vertical and lateral reservoir geometry. Correlations are presented in cross-sections that show interpretations of structure, stratigraphy, and thickness of important reservoir units.

Subsurface correlation is based primarily on stratigraphic continuity, or the premise that similar facies maintain similar stratigraphic thickness between closely spaced wells.

The correlation ofdepositional facies observed in cores, through calibration of log responses can be used to predict the likely facies in nearby wells in studied fields on the basis of the similarity in log responses. Understanding the spatial distribution and properties of reservoir facies is important for predicting reservoir quality and reservoir continuity, which in turn supports implementation of more effective waterflood or CO2 EOR in diverse Dundee oil fields in the Michigan Basin. This chapter addresses the important task of populating the geologic framework with petrophysical properties and well logs data from the three main reservoir facies, including crinoidal grainstone, stromatoporoid boundstone, and fenestral peloidal grainstone/packstone (facies 3, 5, and 7). The goal of this chapter is to examine in

71 depth the need of reservoir properties to implement waterflood or CO2 EOR in the

Dundee Limestone reservoirs.

Reservoir Quality

The quality of a reservoir is a function of petrophysical properties.

\Eetrophysical properties such as porosity and permeability are often highly variable in

carbonate strata and rarely show a regular relationship as in siliciclastics. Carbonate

reservoirs are characterized by the extreme heterogeneity of porosity and

permeability, as a result of depositional and diagenetic processes (Flugel, 2004).

Carbonate rocks have complex porosity distributions as a result of both their

biological genesis and subsequent diagenetic overprinting (Choquette and Pray,

1970). Characterization of carbonate reservoirs is therefore complicated due to the

inherent heterogeneity and complexity of carbonate geological systems. This study

defines three different reservoir types within the Dundee Limestone, which include: 1)

Crinoidal grainstone (facies 3); 2) Stromatoporoid boundstone (facies 5); and 3)

Fenestral peloidal grainstone/packstone (facies 7). Therefore, efficient secondary

recovery of these Dundee reservoirs requires an understanding offluid flow, which in

turn requires a detailed understanding of porosity and permeability within these

facies.

Porosity and Permeability

Porosity and permeability are two ofthe important fundamental properties that

control the storage and movement of fluids in reservoirs. Porosity is the ratio of the

pore volume to the bulk volume of material (Lucia, 1999). The porosity in the

sedimentary rocks split into two major categories; primary porosity forms during the 72 depositional phase (i.e., interparticle or framework growth porosity), and secondary

porosity (i.e., moldic or vuggy porosity), forms during diagenesis during all post-

depositional stages (Flugel, 2004). Schmoker et al. (1985) reported that the carbonate

reservoirs within the United States have porosities ranging from 1-35%, with average

values of 12% in limestone reservoirs and 10% in dolomite reservoirs.

Permeability is the ability of a fluid to pass through a sediment or rock.

Permeability is calculated according to Darcy's law (Eq 1) and commonly expressed

in millidarcy (Flugel, 2004). Permeability is important because it is a rock property

that relates to the rate at which hydrocarbons can be recovered. Additionally, the

viability of a carbonate reservoir is more dependent on its permeability rather than

porosity for hydrocarbon recovery (Tucker and Wright, 1990). Typically in carbonate

reservoirs, permeability values vary between 0.01 millidarcy (md) to well over 1

Darcy. A permeability of 0.1 md is generally considered minimum for oil production

(Lucia, 1999).

Equation 1 Darcy's Law:

Where Q is rate of flow, k is permeability, \i is fluid viscosity, (AP)/L is the potential

drop across a horizontal sample, and A is the cross-sectional area ofthe sample.

Dominant pore types in reservoir facies 3,5, and 7 are commonly interparticle,

intraparticle, and limited fracture and moldic porosity, with the exception of facies 7, which contains predominately fenestral porosity. Comparisons ofall Dundee porosity vs. permeability show no distinct relationship in these reservoirs (Figure 40). The

73 results of conventional core analysis from studied cores show high contrast and

variation in core properties (porosity and permeability). Large differences in the

relationship between porosity and permeability support the complexity of Dundee

reservoirs. However, when porosity and permeability data for each depositional facies

are plotted individually, better correlation relationships became apparent (i.e., facies 3

and 5, Figure 15 and 19, respectively).

Porosity and permeability cross plots typically demonstrates that the crinoidal

grainstone facies has moderate porosity ranges in this reservoir facies from 2% to

12%, with average porosity of 7%, and permeability ranging from 0.1md to 189md, with an average of 14md. Stromatoporoid boundstone facies has moderate to high porosity and permeability with average of 7% and 123 md, respectively. Fenestral peloidal grainstone/packstone facies has the highest porosity and permeability values with average of 9% and 195md. The excellent reservoir quality in the fenestral facies is clearly a result ofa well-connected network offenestral pores developed in the tidal flat facies, which results in higher permeability values. Porosity and permeability relationships in these three reservoir facies (facies 3, 5, and 7) are evidence of generally good reservoir quality indicating that these reservoirs types should be good candidates for effective waterflood or potential C02 EOR injection activity.

Porosity and permeability variations from well to well within the same field and within the same facies are significant. Therefore, the facies are not the only controls on the Dundee reservoir rock properties. There is clearly another factor that controls on reservoir properties (diagenesis), which will be discussed in greater detail in the following section.

74 10000

10 12 Porosity (%)

Figure 40. All core measured porosity-permeability data with the three primary reservoir facies highlighted. As shown, there are strong variations between different types as well as within single types.

DiageneticControls on the Reservoir Quality

The substantial reduction of porosity with progressive burial has been well documented in carbonates (Schmoker and Halley 1982; Halley and Schmoker 1983; Scholle and Halley 1985; Amthor et al. 1994; Brown 1997; Goldhammer 1997), however, it is not true for permeability with depth relations. In carbonate strata primary pore types are highly variable in shape and size. Diagenetic alteration of carbonate pore types adds additional complexity to pore geometry, distribution and reservoir quality (Choquette and Pray, 1970).

Strata within the Dundee Limestone are buried to a range of at least 2600 to 3550 feet (780 to 1100 m). Core and petrographic analyses of the Dundee Limestone

75 indicates that the original fabric of most depositional facies was subjected to diagenetic processes that substantially modified reservoir qualities. Diagenesis typically reduces porosity, redistributes the pore space, and alters permeability characteristics. Dundee porosity is commonly partially occluded by diagenetic cements. The dominant pore-occluding cements are blocky/sparry calcite pore fill and syntaxial overgrowth cement.

In most examples of the patch reef facies (facies 5) primary porosity is only partially reduced by calcite cement. However, in the North Buckeye Field for example, the pores in stromatoporoids are extensively occluded by calcite cement

(Figure 30) resulting in very low porosity and permeability, and poor reservoir quality for this facies. In the grainstone facies (facies 3), interparticle porosity of primary origin is dominant. Grainstone reservoir facies however, commonly contain interparticle porosity-occluding sparry calcite or syntaxial overgrowths cement

(Figure 33), which reduces the size of the interparticle pores and decreases the permeability (<14md average) relative to other reservoir facies. Crinoidal grains are especially subject to development of syntaxial overgrowths that totally occlude effective porosity. The fenestral peloidal grainstone/packstone facies (facies 7) has some fenestral porosity partially filled with blocky calcite spar cement or internal sediment (Figure 31). In the fenestral reservoir facies the effect of this process is relatively minor resulting in the large amount of preserved primary porosity. As a result of the combined influence of primary and secondary processes on the formation, preservation and destruction of porosity, reservoir quality is higher in facies 5 and 7 and lower in facies 3. The high degree of variation in reservoir

76 properties in these important reservoir facies is caused by diagenetic changes to primary pore networks.

Reservoir Compartmentalization and Reservoir Distribution

Reservoir compartmentalization can have a significant impact on effective field development and secondary and enhanced recovery activity.

Compartmentalization caused by vertical facies variations and fluid flow barriers or lateral depositional discontinuities can have an adverse effect on oil or gas recovery factors by reducing drainage and sweep efficiency. Understanding the nature and geological origin of compartmentalization in Dundee reservoirs is a key to predicting connected reserves, and effectively optimizing field development in order to increase production rates and ultimate recovery. Reservoirs in Dundee oil fields are compartmentalized at both an inter-well and reservoir-scale. In the studied fields the reservoir facies are vertically compartmentalized by impermeable facies, which baffle and inhibit vertical fluid flow (i.e., facies 2 and 6).

The patch reef and peritidal facies (facies 5 and 7) form important hydrocarbon producing facies in most Dundee oil Fields. The patch reef facies forms a potential reservoir when the open galleries of the stromatoporoids and the interparticle and intraparticle pores are well connected and not cemented, resulting in good reservoir quality. A detailed study of core in the stromatoporoid boundstone facies (23 feet) of Havens-Denham #1; Permit #43382 well at the South Buckeye

Field revealed that the patch reef are likely highly compartmentalized growth structure resulting in baffles and barriers to fluid flow in the reservoir unit

(McCloskey, 2012). This was documented by a high degree of variation of porosity

77 and permeability values (Appendix D). The fenestral reservoir unit (facies 7) is a succession of interstratified peritidal and lagoonal facies. This interstratification further compartmentalizes the reservoir (Figure 41). The lagoonal facies (facies 6) varies in thickness from a foot to several feet, and appears to be laterally correlative and relatively continuous (e.g., Mt Pleasant Field, Appendix B). Lagoonal facies have high potential to act as baffles or flow barriers affecting the reservoir production performance. Few of these impermeable beds (lagoonal facies) may vertically compartmentalize the reservoir interval (Appendix B). The heterogeneous characteristics of the reservoir are well demonstrated in the frequent vertical variations of core derived porosity and permeability (Appendix D). The crinoidal grainstone facies (facies 3) however, also contributes to reservoir volume. This facies occurs as thin beds (1-2 ft) usually below the stromatoproid boundstone facies as discrete bedded packages (5-9 ft) internally separated by impermeable facies (e.g., facies 2 and 6). In contrast, the crinoidal grainstone facies occurs as a significant, thickly bedded and separate unit in the West Branch Field with a composite thickness of 40 feet (12 m). This facies might have more enhanced recovery potential because of its lower primary recovery, porosity and permeability values and greater lateral extent compared to the stromatoporoid boundstone facies (see below).

Stratigraphic Correlations and Cross-sections

Wire-line logs respond to petrophysical properties and not to geologic properties (i.e. rock lithology). Wire-line logs, for instance, may not be used to differentiate between grainstone and wackestone or between grain types. However, wire-line logs can distinguish different rock types based on the bulk densities/porosity

78 relationships (Lucia, 1999). Wire-line logs can be extremely valuable in inferring several reservoir properties (e.g., porosity). In this study, on the basis of core to log calibration, log response corresponds to core and core analysis data with reasonable consistency.

The primary stratigraphic factors that influence recovery efficiency are reservoir continuity and associated permeability heterogeneity. The depositional model construction and vertical successions of facies and rock fabrics obtained from core descriptions was extended to electric-log-facies correlation field-wide to expand the coverage of one dimensional data. The stratigraphic correlation is based upon a grid of regional wire-line log cross-sections, tied to cored wells. Wire-line logs that have been used for this correlation method include gamma-ray (Gr), neutron porosity

(NPHI), and bulk density (RHOB). Prior to establishing the correlation between the continuous well log data set and core measurements was performed, three steps were considered: 1) Shifting the depth of core to match the depth of the wire-line log (±1-

10 feet). 2) Cross-sections were hung on the contact between the Rogers City and The

Dundee. 3) Picking distinct well log signature that could be directly related to distinct facies types in the recovered core. Some depositional facies (i.e., facies 1, 6 and 7) have similar log characteristics when discriminated by bulk density and neutron porosity logs (Figure 41). This correlation work contributed to a better understanding of the reservoir geometries and may help explain possible waterflood or C02 performance.

In North Buckeye, Wise, and Mt Pleasant fields production comes from one uniform reservoir type, the fenestral reservoir facies. The cross-section of this reservoir facies was constructed in the Mt Pleasant Field only because of better

79 available data control. It is inferred that this degree oflateral continuity can be applied to both the Wise and North Buckeye fields. However, in these fields, due to lack of modern wire-line logs, core data and conventional core analysis only few cross- sections can be confidently established (Appendix E).

A field-wide cross-section (Figure 41) was constructed from well logs in the

Mt Pleasant Field in Isabella and Midland Counties. This cross-section was constructed where conventional cores from wells located from the northwest to southeast provide good indication of overall reservoir lateral continuity and reasonable petrophysical homogeneity. In the Mt Pleasant Field the predominant facies are fenestral peloidal grainstone/packstone and skeletal wackestone facies. It is composed of several shallowing upward sedimentary cycles. These cycles consist of shallow lagoonal wackestone that grade upward into fenestral grainstone/packstone suggesting shallower water, intertidal to supratidal conditions. The stratigraphic cross- section (Figure 41) demonstrates that these facies are correlative throughout the entire field representing multiple regressive cycles. These regressive cycles are bounded at the base by an interpreted flooding surface observed on Pfund #1; Permit #36259 well

(Figure 41). The flooding surface is observed as a crinoidal skeletal wackestone representing an open marine depositional environment similar to the Rogers City facies (Appendix B). This flooding surface is laterally traceable throughout the field based on the distinctive gamma ray log response. The geometry and development of the fenestral reservoir facies is quite extensive both vertically and laterally across distances of up to 10 miles and creates a generally uniform producing zone throughout the Mt Pleasant Field. The packages of the fenestral reservoir facies are separated by a few inches to several feet of non-productive skeletal wackestone facies

80 (facies 6). The most continuous and highest porosity and permeability reservoir zones are concentrated in the upper Dundee with an average thickness of 16 feet. Highest confidence was placed on core data, where lateral relationships and significance of reservoir unit could be determined through depositional facies correlation. The interpretation of substantial lateral continuity of the peritidal fenestral reservoir facies is also supported by modern analogs of Persian Gulf (Figure 42). This modern analog, in terms of the facies distribution closely matches the fenestral reservoir facies of portions of the Middle Devonian Dundee of the Michigan Basin.

MILLER. VIOLA MT PLEASANT UNIT TRACT 55 SIERRA LAND CO , INC

ISABELLA MIDLAND MIDLAND Mount Pleasant Mount Pleasant Mount Pleasant

Skeletal Crinoidal Wackestone B Fenestralpeloidal Grainstone/Packstone Skeletal Wackestone

Figure 41. Dip oriented stratigraphic cross-section showing inferred lateral continuity of the fenestral reservoir facies in the Mount Pleasant field. The stratigraphic datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City/ Dundee contact). A

1 laterally continuous, overall regressive cycle consisting of interbedded fenestral peloidal grainstone/packstone and skeletal wackestone cycles is located above an interpreted flooding surface marked with a red dashed line. The flooding surface is traceable throughout the field as shown in this cross-section. The fenestral facies (light blue line and) skeletal wackestone (green line) are correlative throughout. RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI = neutron porosity log, RHOB - bulk density log.

Lagoons Coral Reef Tertiary Ls Shoal Tidal flat Sabkha Offshore outcrop

10 km

Figure 42. Modern analog from the Persian Gulf is used to demonstrate interpretations of lateral continuity in peritidal facies (Modified from Noel and Robert, 2010).

In the South Buckeye Field where the main reservoir type is the patch reef, there is a limited lateral extent of the patch reef facies within the Dundee Limestone.

82 Insights from two cores (Nusbaum Kern 3-W and Fitzwater 6) examined in this field

were supplemented with inspection of several cores in South Buckeye Field by

McCloskey (2012). These cores were selectively correlated in strike well log cross

section, which shows the vertical and lateral variation ofthe patch reef facies. Due to

this spatial variability closely spaced wells (>1 mile) in this cross section, features

such as pinch-outs and gradual facies transitions are clearly documented (Figure 43).

An interesting observation from this cross-section is that in the Oard well, the reservoir facies (facies 5) is completely absent. This relationship and the overall variation in stratigraphic position and thickness of the boundstone reservoir facies confidently supports the limited lateral continuity of the patch reef facies across the

South Buckeye Field within distances a little as 0.4 miles. The stromatoporoid boundstone reservoir facies therefore has distinct petrophysical and reservoir geometry properties compared to other reservoir facies in the Dundee Limestone.

The characterization ofpatch reef reservoirs is often aided by modern analogs to infer the spatial distribution offacies. The distribution ofmodern patch reefs across the Belize coast for example, shows significant variability of patch reefs within 0.25 mile (Figure 44) and helps explain the patch reef geometry in the South Buckeye

Field (McCloskey, 2012). In particular, modern environments are an important tool for visualizing the spatial distribution of facies in a reservoir during a single slice through time (Grammer et al., 2004).

The West Branch Field was extensively studied by Curran (1990) and Curran and Hurley (1992). In this study only one cored well (Grow #4) was studied in detail and this analysis was supplemented with inspection of 11 cores from Curran (1990).

Based on the observation from 11 cores, Curran concluded that most production

83 comes from primary porosity in the grainstone facies (facies 3). From three field-wide cross-sections in the West Branch field, Curran has suggested that the reservoir facies

(facies 3) was correlative up to 2-3 mile.

As confirmed from core, conventional core analysis, wire-line log, and production history in this study, the hydrocarbon production at West Branch Field has occurred primarily from the shoal grainstone facies (facies 3)whereas with secondary contributions from the shoal grainstone reservoir facies in the South Buckeye Field.

Total reservoir thickness in the producing wells ranges from 20 to 30 feet in West

Branch Field. The shoal reservoir facies has a grain-supported architecture with minimal carbonate mud, and therefore, has the highest reservoir capacity. The pore systems of the shoal reservoir facies consist of interparticle and limited moldic and vuggy pore types. The correlation between porosity and permeability for crinoidal grainstones is known to be very good in this reservoir (Figure 19). The geometry of the grainstone reservoir facies is quite extensive both vertically (40 feet thick) and laterally across distances of up to 3 miles and creates a uniform producing zone throughout the West Branch Field. The shoal grainstone facies is associated with impermeable bioturbated peloidal grainstone/packstone and skeletal wackestone facies (Appendix B). In contrast, the shoal grainstone facies in the South Buckeye

Field is not well developed either vertically or laterally and results in limited lateral continuity ofthe reservoir facies (Figure 43, red color). WOODRING ESTATE FITZWATER O. OARD NUSBAUM KERN STATE BUCKEYE D 41014 36730 35697 43383 41122

RGRC

GLADWIN GLADWIN GLADWIN GLADWIN GLADWIN Buckeye South Buckeye South Buckeye South Buckeye South Buckeye South

(Skeletal Crinoidal • Bioturbated Peloidal •Crinoidal I Coral-stromatoporoid Stromatoporoid Wackestone Grainstone/Packstone I Grainstone Floatstone Boundstone

Figure 43. Stratigraphic cross section (A A') across South Buckeye Field showing lateral variations in the stromatoporoid boundstone facies (marked in yellow). Note the absence of reservoir facies at O. Oard well indicates that the stromatoporoid boundstone facies is laterally discontinuous (blue line). This cross-section was constructed from well logs in the South Buckeye Field, and the datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City and Dundee contact). RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI= neutron porosity log, RHOB = bulk density log.

85 Figure 44. Example of modern patch reef complex in the Belize coast. Note the X-X' cross-section highlights and illustrates the discontinuous and irregular geometries and sizes ofpatch reefs growing on this carbonate platform.

This chapter explored the detailed process of reservoir characterization. In terms of the application of this study is to maximize the recovery of bypassed or trapped hydrocarbons in these reservoir facies (Facies 3, 5, and 7), it is critically important that the operator have access to scientifically predict the geometrical distribution of the reservoir facies in the Dundee Limestone reservoirs. One of the interesting results from this study is that in contrast to the layer-cake geology characteristic of peritidal settings, the lateral relationships of peritidal facies, shown in figure 41, demonstrate extensive continuity ofthis facies.

86 CHAPTER VI

DUNDEE HISTORIC PRODUCTION AND ENHANCED OIL RECOVERY (EOR) POTENTIAL

The Middle Devonian Rogers City and the Dundee Limestone formations are prolific hydrocarbon reservoirs that have produced in excess of 375 million bbl ofoil

(MMBBL) from more thanl37 fields mostly in the central part ofthe Michigan Basin.

The majority ofthe Dundee oil Fields were discovered in 1930s and 1940s. However, wells in many of the fields are now abandoned due to aggressive development during the early stages of production resulting in overdrilling, pressure loss, or water coning

(Montgomery et al., 1998).

The Rogers City and Dundee reservoir types are characterized as fracture controlled and/or facies controlled, respectively. The fracture controlled dolomite reservoirs occur predominantly in the central Basin (Ten Have, 1979). The fractured controlled reservoirs were generally more productive than facies controlled reservoirs, although the facies controlled are complex, and often less understood in light of deposition and diagenesis (Luczaj et.al. 2006). Wood et al., (1998) reported that the most productive intervals in the Rogers City and Dundee come from the sucrosic dolomite facies of the Rogers City in the central part of the Basin. However, in the eastern part of the Basin, where the Dundee reservoir produces primarily from sedimentary facies controlled limestone reservoirs, the most productive zones in the

Dundee reservoirs are related to primary porosity in lenticular beds of skeletal grainstones and stromatoporoid and coral patch reef facies (Curran and Hurley, 1992;

Wood et.al, 1998). This study adds another important reservoir facies, the peritidal facies, which forms a main producing unit in several Dundee Limestone fields (Mt

Pleasant, Wise and North Buckeye fields). This facies has high reservoir quality and

87 laterally (dip and strike oriented) extensive reservoir geometry. It extends up to 10 miles across the Mount Pleasant Field based on core to log correlation. On the basis of cumulative oil production, the peritidal facies in the Dundee Limestone outweighs all other producing facies in importance.

Field production characteristics in the Dundee Formation (Rogers City and

Dundee, Figure 45) fields indicate at least two distinct field drive mechanisms: 1) bottom water and 2) gas expansion. These mechanisms have been interpreted based on water production and pressure decline curves (personal communication, Harrison,

2012). Pressure decline is more pronounced in the gas expansion fields whereas the initial pressures are generally preserved in the inferred bottom water drive, Rogers

City dolomite fields.

This chapter briefly compares Dundee Limestone production history along with geologic framework and petrophysical properties to describe reservoir performance and help predict the potential recoverable hydrocarbons in the patch reef, shoal, and peritidal reservoirs.

Vernon Field __^, Crystal Field

DUND

Figure 45. Average per well water production from representative fields with two distinct trends ofrelatively high water production per well from inferred

88 bottom water drive in Rogers City (RGRC) dolomite Fields (Fork, Vernon, Crystal, and Deep River Fields) vs. relatively low water production from probable gas expansion drive in Dundee (DUND) Limestone Fields (West Branch and South Buckeye Fields, from Harrison, 2001).

Historic Production

There are a number of known limitations in the historic production data, for

Devonian carbonates including the Dundee Limestone formation. There is only modest production since 1982 and the production is often grouped into multi well leases. Usually there is no digital data before 1997. From 1934 to 1986 the State of

Michigan produced an annual statistical summary of oil and gas fields in paper records. It is only annual and cumulative field production and does not contain individual well or lease information. For many of the older fields, there is a gap in annual field production data from 1986 to 1997. Additionally, some of these fields have problems with combining data from different Devonian formations and it is often not possible to determine whether production came from Lucas, Dundee or

Traverse formations. The three fields studied here however, do have reasonably reliable production data availability. These fields include West Branch, South

Buckeye, and Mount Pleasant fields.

Many old producing fields in the Dundee are interpreted to have had less than

50% of the oil reserves recovered from the estimated original oil in place (OOIP).

Production rates from these reservoirs decreased because reservoir pressure from the gas expansion drive is nearly depleted possibly due to extensive flaring of natural gas early in the field history. Recovery from pressure-depleted zones can be increased by repressurizing the reservoir. Therefore, the Dundee Limestone fields were selected as

89 the focus of this study because of the fundamentally greater enhanced oil recovery

(EOR) potential compared to bottom water drive, Rogers City reservoirs.

West Branch Field

West Branch oil field is an anticlinal trap with northwest-southeast trend that is primarily located in T22N-R2E, (West Branch Township) in Ogemaw County,

Michigan. The field is approximately nine miles long and one mile wide (Ten Have,

1979). West Branch Field has produced hydrocarbon from several Middle Devonian formations including the Dundee. However, the Dundee reservoir is by far the dominant producing unit in the West Branch Field. The first Dundee production was discovered on March 8, 1934 with the completion of Pure Oil Company's # 1 Fisk well in Section 27 of West Branch Township, Ogemaw County. In this well the

Dundee oil reservoir occurs at a depth of 2625 ft (800m) with initial production (IP) of 21 BOPD (barrels of oil per day). Average gravity of produced oil is 36.8° API units (Mortl, 1991).

In January, 1966 development ofthe West Branch Field proceeded on ten-acre spacing, with the wells located in the centers of governmental-surveyed quarter- quarter-quarter sections. Drilling by several independent producers extended the field to the southeast into Section 6, T.21N., R.3E., Mills Township, and to the northwest into Sections 23 and 24, T.22N., R.1E., Ogemaw Township (Vugrinovich and

Matzkanin, 1981). In 1974, the Marathon Oil Company commenced a field-wide secondary recovery program that water-flooded the Dundee reservoir using a five-spot well pattern. Oil production reached its second-highest peak in 1981 (Figure 46), when about 300,000 barrels was produced. A steep decline ensued after 1986 and is sustained to date, averaging 5.5% per year (Figure 46).

90 The West Branch Field produces oil from grainstone reservoir facies with an average porosity and permeability of7% and 14md, respectively. Thickness ofthe pay zone is 20-30 feet (Curran and Hurley, 1992). The reservoir unit in the field is thought to extend over approximately 1870 acres. Since discovery, more than 325 wells have been drilled producing an excess of 14 MMbbl. The estimated original oil in place

(OOIP) is 26.4 MMbbl, however, 9.5 MMbbl was produced through primary recovery and 4.7 MMbbl from secondary recovery to date. The total percentage ofestimated oil recovery (primary and secondary) relative to OOIP is 53%. As of 2010, the field produces approximately 51,400 barrels per year (Figure 46).

West Branch Oil Field Production History 1,000 •OilProd

5 6°oPi iniaiy Annual Decline 5.5° o Secondaiv Annual Decline © e

100

10

^r^Oro«3cnrvitr>00'-t'*r^Onni£)CrirNLnoOr-<'g-r--Oroi£>0 mro^t^^-^iniAiflvovovor-rxr^r^oooooocriiCiooooo

«H»-HiH»-ti--l«-1r-lr-tr-»T-lr-l.—l<-lT-lr-li-HtHr-lt-t*-lr-lf-lrs|r>jrvirsl Production Year

Figure 46. Performance history of the West Branch Dundee reservoir showing the oil production per year (green line) associated with primary and secondary annual decline (pink line). In the West Branch Field, the waterflood began in 1966 (from Harrison, 2012).

91 South Buckeye Field

South Buckeye oil field is located on a major anticline fold in T18N-R1W, of

Buckeye Township, in Gladwin County, Michigan, with a few wells located east of the range line in Hay Township T18N-R1E (Addison, 1940; Harrison, 1991). The

South Buckeye oil field has produced oil and gas from several Middle and Late

Devonian formations including the Dundee. The Dundee reservoir, however, is the primary unit in the South Buckeye Field and was discovered on July 20, 1936 with the completion of the Oard No. 1. The Dundee oil reservoir occurs at depth of 3570 ft

(1,088 m) in this well, and the well flowed at rates (IP) greater than 135 BOPD

(Addison, 1940; Mortl, 1991). After production for more than fifty years, the Wiser

Oil Company started a secondary recovery program by water flooding portions of the field using a five-spot well pattern (Harrison, 1991).

The South Buckeye Field produces oil from patch reef reservoir facies with an average porosity and permeability of 7% and 123md, respectively. Average thickness of the pay zone is about 11 feet. Since discovery, more than 240 wells have been drilled producing an excess of 7.7Mbb through 2011. However, only 45 wells are active to date, 21 currently water injection wells, and 177 wells were plugged and abandoned. Average gravity of produced oil is 39° API units (personal communication, Harrison, 2012). The estimated original oil in place (OOIP) is about

27 MMbbl, however, 5.4 MMbbl were produced through primary recovery and 2.3

MMbbl through secondary recovery. The total percentage (primary and secondary) of the OOIP is 28%. As of 2011, the field produces approximately 12,000 barrels per year (Figure 47). That suggested that the recovery efficiencies were only about 28% of

OOIP. In this field, however, original oil in place may be overestimated due to the patchy distribution ofreservoir facies (see below).

92 South Buckeve Oil Field Dundee .Annual Production 10,000 10000

•OilProd 6.0% Annual Decline •BrineProd a 1,000 1000 § SB

© e

uso^cornr^rHLncnror^r-iLncrinor^T-iLncri ro«3i£>r-.r^oooooocr>cr>ooo ocScScriOCiCiCT^cricric^oc^oc^c^ooo r-tr-t.-Ht-<*-l<-l*-lT-<J

Production Year

Figure 47. Performance history of the South Buckeye Dundee reservoir showing the annual oil production (green curve) and annual water production (blue curve) associated with annual decline (pink line). Pilot waterflooding began in 1980 (from Harrison, 2012).

Mount Pleasant Field

The Mount Pleasant oil field was the first commercial Dundee field in

Michigan, and was discovered in 1928 in Mt Pleasant Township, Midland County,

Michigan. Mt Pleasant Field lies in both Isabella and Midland Counties (T18-14N-

2W), Michigan (Mortl, 1991).When the Mount Pleasant Field was discovered in the central basin, serious attention from the petroleum industry became directed toward the Michigan Basin (Addison, 1940). The depth ofthe Dundee reservoir is at 3,545 ft

(1,080 m). After fifty five years of production, several producers commenced a pilot secondary recovery program that water-flooded portions of the field (personal

93 communication, Harrison, 2012). However, the size of these pilot projects is small, and only limited data on the performances ofthese pilot projects is publicly available.

The Mount Pleasant Field produces oil from fenestral reservoir facies with an average porosity and permeability of 9% and 195md, respectively. Average thickness of the pay zone is approximately 40 feet. The reservoir unit of the field is thought to extend over approximately 7310 acres. Since discovery, 589 wells have been drilled in the field. Cumulative production from this reservoir exceeds 29 MMbbl ofthrough

2011. There are currently only 10 producing wells, 4 water injection wells, 2 observation wells, and 573 wells were plugged and abandoned. Average gravity of produced oil is 41.2° API units (personal communication, Harrison, 2012). The estimated original oil in place (OOIP) is about 66.8 MMbbl, with 28.3 MMbbl produced through primary recovery and 1.2 MMbbl produced through secondary recovery. Only 44% of the original oil in place has been recovered from Mount

Pleasant Field during the primary and secondary production phase. As of 2011, the field produces approximately 15000 barrels per year (Figure 48).

Mount Pleasant Oil Field Dundee Annual Production 10000 1 600

1000

a 100

10

900l\HIO'J»(NICO

Figure 48. Performance history of the Mount Pleasant Dundee reservoir showing the annual oil production (green curve) and annual water production (blue

94 curve) associated with 4.5% annual decline (pink line). Pilot waterflooding began in 1980 (from Harrison, 2012).

Enhanced Oil Recovery (EOR) Potential

Enhanced oil recovery (EOR) is a term used for a wide variety of techniques for increasing the amount of crude oil that can be extracted from an oil field. Gas injection (including CO2) and water injection for pressure maintenance is presently the most commonly used approach to enhance recovery (Grammer et al., 2008).

Recovery efficiency, which is also called oil efficiency factor, is expressed as a ratio ofrecovered oil to original oil in place (Larue, 2004, Eq. 1).

cumulative production Eq. 1. Recovery Efficiency = ——-—— * 100 original oil in place

In this study, the Dundee Limestone produces oil predominately from three different reservoir types; the stromatoporoid boundstone (patch reef), crinoidal grainstone (shoal), and fenestral peloidal grainstone/packstone (peritidal). These reservoir facies have an average thickness of the pay zone is 11 feet, 20-30 feet, and

40-60 feet, respectively. Cumulative production from a patch reef reservoir in South

Buckeye Field exceeds 7.7 MMbbl with primary recovery efficiencies of approximately 20% (Eq.l). Production from the South Buckeye Field declined significantly in the primary phase of production possibly due to either the reefs have reached or are nearing their economic limit in the primary phase of hydrocarbon production or reservoir pressure from the gas expansion drive is nearly depleted. However, the South Buckeye Field has been converted to secondary recovery operations, primarily through water injection for pressure maintenance, conducted in

95 the late 1980s (Figure 47), with additional recovery of approximately 45 % of the primaryrecovery. Overall, the higher production from the patch reef facies indicates a good response to secondary waterflood operations. The good response is attributed to good overall reservoir quality and interconnectivity of the pore system in the patch reef facies. Therefore, more recoverable oil can be extracted from the patch reef facies based on the reservoir properties and estimated OOIP. However, the limited lateral continuity of the patch reef facies and problematic OOIP estimates probably makes this reservoir facies less efficient for EOR compared with other two facies (3 and 7).

The total recoverable oil reserves from shoal reservoir facies in the West

Branch Field are estimated to be about 26.4 MMbbl. The shoal reservoir facies has produced in excess of 9 MMbbl in primary recovery and nearly 4.7 MMbbl from secondary waterflood. The enhanced oil recovery pilot and field-wide waterflood projects in the West Branch Field has achieved significant secondary waterflood oil recovery. This facies generally produces from a uniform pore type (interparticle porosity) and has high porosity and moderate permeability with an average of 7% and

14md, respectively. The good reservoir efficiency in the shoal facies is attributed to the lateral continuity ofthe facies and good interconnectivity ofthis facies due to the nature of the pore system (pore-throat size distribution) as well as of the amount of porosity. Pore-throat size distribution is one of the important factors determining permeability because the smallest pore throats are the bottlenecks that determine the rate at which fluids pass through a rock (Kopaska-Merkel, 1991). The shoal reservoir facies appears to possess good reservoir quality and good vertical and lateral continuity on the basis of core analysis, production performance and core to log correlation. Therefore, the shoal reservoir facies is a good candidate for enhanced oil recovery to produce bypassed oil from shoal reservoir facies in the Dundee limestone.

96 Production in the Mount Pleasant Field started in the late twenties and the

field began experiencing steep production rate declines (Figure 48). After fifty years of production, the field was converted to a pilot waterflood program. The field production characteristics, including the heterogeneous nature of the field (i.e.,

especially porosity and permeability), may contribute to the different reservoir performance. Distribution of porosity and permeability for three selected wells (

Pfund 1, permit # 36259; McClintic 3, permit # 36367; and Mt Pleasant Unit Tract 55, permit # 39770) demonstrate that (Figure 49) the fenestral reservoir (facies 7) within the Dundee Limestone is thought to have a dual permeability system: a higher

permeability component consisting of interconnected vugs and solution-enhanced fractures and stylolites seams, and a lower permeability component consisting of

microporosity and interparticle porosity. Through the primary production phase, fluids

move more easily through the higher permeability component. However, a large total volume of hydrocarbons are stored in the lower permeability component. In light of

reservoir quality shown in porosity vs. permeability cross plot, the better production

probably resulted from the better reservoir quality zones (Figure 49). Additionally, the estimated primary recovery efficiency in the Mount Pleasant Field is 42%, indicating that the higher permeability component of the dual porosity system is being swept very efficiently. The pilot waterflood program in the field resulted in low recovery efficiency (<2% of OOIP) because the oil in the lower permeabilityreservoir type has been ineffectively swept by the injected fluid.

Importantly, the remaining oil in the Mount Pleasant Field is concentrated in the low permeability component and would be a target for waterflood or CO2 enhanced oil recovery (EOR). The injected fluid (water or CO2) flows at a faster rate through the high-permeability grainstone intervals and at a lower rate in the low-

97 permeability of microporosity and interparticle porosity grainstone intervals, effectively bypassing much of the oil in the lower permeability component. This suggests that the microporosity and interparticle porosity are excellent targets for waterflood or CO2 enhanced oil recovery because they have moderate porosity, low permeability, and high initial oil saturation (Appendix D).

In North Buckeye, Wise, and Mt Pleasant fields production comes from one uniform reservoir type, the fenestral reservoir facies. Analysis of this reservoir facies was only documented in the Mt Pleasant Field because of better available data control. It is inferred that this degree of the reservoir properties and reservoir geometries can be applied to both the Wise and North Buckeye fields. The insights from the geologic reservoir characterization and field production history provide an understanding of the reservoir architecture, pore networks, and flow units within the

Dundee Limestone in six fields. It is this foundation that gives some context to areas with better reservoir development and economic waterflood or CO2 EOR potential. The geological framework, production performance, and operational understanding should provide useful guidance for future waterflood or C02 EOR potential expansion. Fundamentallythe fenestral facies performance differently than grainstone or patch reef. North Buckeye and Wise fields both perform like Mount Pleasant does.

98 Porosity vs. Permeability for Facies 7 10000 4

♦Permit #36259 •Permit # 39770 A Permit#36367

6 8 10 14 10 Porosity %

Figure 49. Example of three selected wells of the fenestral facies showing the heterogeneity (porosity and permeability) within a single well. Note that the fenestral reservoir facies has a dual permeability system, a higher permeability component consisting of interconnected vugs and solution- enhanced fractures and stylolites seams (blue circle), and a lower permeability component consisting of microporosity and interparticle porosity (red circle).

99 CHAPTER VII

CONCLUSIONS

This study evaluates the depositional and diagenetic controls on reservoir quality within several Dundee Limestone oil fields in order to identify reservoir-prone facies and predict their distribution. The distribution ofreservoir facies in the Dundee

Limestone is controlled by primary depositional processes in conjunction with a suite of diagenetic processes. In the fifteen wells described in this study, seven distinct depositional facies have been identified in the Dundee, as well as Rogers City. These facies were placed into an idealized vertical succession in order to evaluate a sequence stratigraphic model oh the basis of an inferred depositional model from deepest/open marine to shallowest/tidal flat.

Oil production occurs from at least three different reservoir facies; 1)

Crinoidal grainstone; 2) Stromatoporoid boundstone; and 3) Fenestral peloidal grainstone/packstone in different Dundee fields. The other four facies 1) Crinoidal skeletal wackestone; 2) bioturbated peloidal grainstone/packstone; 3) Coral- stromatoporoid rudstone; and 4) Skeletal wackestone, which most commonly form seals and baffles. This is largely due to their disconnected pore space, consisting primarily oflimited distribution ofinterparticle, moldic and vuggy pores. Facies 3 and

5 very rarely have reservoir potential when molds are dissolved and the isolated vugy porosity is interconnected by stylolitization and fracturing.

Examination of conventional core analysis data from the hydrocarbon reservoir facies indicates that these facies have variable porosity and permeability relationships. The correlation between porosity and permeability of the reservoir facies are known to be poor in the Dundee limestone due to the varying connectivity of different pore types. Reservoir quality in these fields is controlled by lithologic

100 variations and the spatial heterogeneity in diagenetic processes. Variations in diagenetic alterations such as porosity, permeability and lithology, could produce zones with different reservoir properties and so different petrophysical behaviors. The combination of porosity and permeability data in terms of reservoir quality provides a convenient starting point to address the differences between facies and between reservoir zones.

This study provides additional information on the opportunities for implementing water flooding or C02 enhanced oil recovery (C02-EOR). With similar subsurface reservoirs, waterflood or enhanced recovery initiatives should understand the reservoir quality and geometry to evaluate the potential of preferential sweep of unrecovered hydrocarbon. The implementation of EOR in more laterally continuous reservoir (i.e., fenestral peloidal grainstone/packstone facies) should be more efficient and effective than typically spatially isolated reservoir facies such as patch reef facies of the South Buckeye Field. For example, the patch reef reservoir (facies 2), has distinct petrophysical reservoir properties and also has distinct reservoir geometry properties, in particular laterally discontinuous patch reef facies. This characteristic results in less efficient for EOR potential.

101 BIBLIOGRAPHY

Addison, C.C., 1940,Buckeye Oil Field, Gladwin County, Michigan: American Association ofPetroleum Geologists, Bulletin, v. 24, p. 1950- 1982.

Amthor, J.E., Mountjoy, E.W., And Machel, H.G., 1994, Regional-scale porosity and permeability variations in Upper Devonian Leduc buildups: implications for reservoir development and prediction in carbonates: American Association of Petroleum Geologists, Bulletin, v. 78, p. 1541-1559.

Bathurst, R. G. C. (1975), Carbonate sediments and their diagenesis, Amsterdam, Elsevier, 658 p.

Blakey, R.C., 2011, Colorado Plateau Geosystems, Inc. (http://cpgeosystems.com/paleomaps.html)

Brown, A., 1997, Porosity variation in carbonates as a function ofdepth: Mississippian Madison Group, Williston Basin, in Kupecz, J.A., Gluyas, J., and Bloch, S., eds., Reservoir Quality Prediction in Sandstones and Carbonates: American Association ofPetroleum Geologists, Memoir 69, p. 29-46.

Catacosinos, P.A., Harrison III, W. B., and Daniels, P. A., Jr., 1990, Structure, Stratigraphy, and Petroleum Geology ofthe Michigan Basin in Leighton, M.W., Kolata, D.R., Oltz, D.F., and Eidel, J.J., Interior Cratonic Basins: American Association ofPetroleum Geologists, Memoir 51, p. 561-601.

Choquette, P.W. and Pray, L.C., 1970, Geologic Nomenclature and Classification of Porosity in Sedimentary Carbonates: American Association ofPetroleum Geologists, Bulletin, v. 54, n. 2, p. 207-250.

Cohee, G. V., and Landes, K. K, 1958, Oil in the Michigan Basin: Habitat ofOil-a Symposium, p. 473-93.

Curran, B. C, 1990, Reservoir Geology ofthe Dundee Limestone, West Branch field, Michigan: M.S. thesis, Western Michigan University, Kalamazoo, Michigan, 158p.

Curran, B. C, and Hurley, N. F, 1992, Geology ofthe Devonian Dundee Reservoir, West Branch Field, Michigan: AAPG Bulletin, v. 76, p. 1363- 1383.

Doveton, J.H., 2004, Geologic log interpretation: CD-ROM reprint ofSociety for Sedimentary Geology Short Course Notes 29. p. 110-169.

Dunham, R. J., 1962, Classification ofCarbonate Rocks According to Depositional Texture, in W. E. Ham, ed., Classification ofCarbonate Rocks, A symposium: American Association ofPetroleum Geologists Memoir 1, p. 108-121.

102 Ehlers, G. M., and R. E. Radabaugh, 1938, The Rogers City Limestone, a New Middle Devonian Formation in Michigan: Papers of the Michigan Academy of Science, Arts, and Letters, v. 23, p. 441^46.

Ehlers, G. M., 1945, Geology of the Mackinac Straights Region: Michigan Geological Survey Publication 44, Geology Series 37, p. 21-120.

Ehlers, G. M., J. E. Smith, and F. D. Shelden, 1959, Surface Stratigraphy of the Mackinac Straits Region, in F. D. Sheldened., Geologyof MackinacIsland and Lower and Middle Devonian South ofthe Straits ofMackinac: Michigan Basin Geological Society Guide Book: Ann Arbor, Michigan, Edwards Brothers, p. 13-18.

Embry III, A. F., and Klovan, J. E., 1971, A Late Devonian ReefTract on northeastern BanksIsland, N.W.T., Bulletinof Canadian Petroleum Geology, v. 19, no. 4, p. 730-781.

Fisher, J. H., 1969, EarlyPaleozoic Historyof the Michigan Basin, in Studies of the Precambrian ofthe Michigan Basin: Michigan Basin Geol. Soc. Ann. Field Excursion, p. 89-93.

Fisher, J.H., Barratt, H.W., Droste, J.B., and Shaver, R.H., 1988. Michigan Basin. In: Sloss,L.L. (ed.) Sedimentary Cover- North American Craton, Geological SocietyofAmerica, Boulder Colorado, The Geology ofNorth America, v. D-2, p. 361-382.

Fowler, J. H., and Kuenzi, W. D., 1978, Keweenawan turbidities in Michigan (deep boreholered beds): a foundered Basin sequencedevelopedduring evolutionof a proto-oceanic rift system: Journal of Geophysical Research, v. 83, p. 5833- 5843.

Flugel, E., 1982, Microfacies Analysis of Limestone: Springer-Verlag Berlin, 633p.

Flugel, E., 2004, Microfacies of Carbonate Rocks: Springer-Verlag Berlin, 976p.

Gardner, W. C, 1974,Middle Devonian Stratigraphy and Depositional Environments in the Michigan Basin: Michigan Basin Geological Society Special Papers 1,p. 1-138.

Goldhammer, R.K., 1997, Compaction and decompaction algorithms for sedimentary carbonates: Journal ofSedimentaryResearch, v. 67, p. 26-35.

Grammer, G. M., Harris, P. M., and Eberli, G. P., 2004, Integration of Outcrop and Modern Analogs in ReservoirModeling: Overview with Examples from the Bahamas, in G. M. Grammer, P. M. Harris, and G. P. Eberli, eds., Integration of

103 Outcrop and Modern Analogs in Reservoir Modeling: American Association of Petroleum Geologists, Memoir 80, p. 1-22.

Grammer, G. M., Barnes, D. A., Harrison III, W. B., Sandomierski, A. E., and Marines, R. G., 2008, Practical synergies for increasing domestic oil production and geological sequestration ofanthropogenic C02: An example from the Michigan Basin, in M. Grobe, J. C. Pashin, and R. L. Dodge, eds., Carbon dioxide sequestration in geological media—State ofthe science: American Association ofPetroleum Geologists, Studies 59, p. 1- 18.

Halley, R.R., and Schmoker, J.W., 1983, High porosity Cenozoic carbonate rocks of south Florida: progressive loss ofporosity with depth: American Association of Petroleum Geologists, Bulletin, v. 67, p. 191-200.

Haq, B. U., and Schutter, S. R., 2008, A Chronology ofPaleozoic Sea-Level Changes, Science, v. 322, no. 5898, p. 64-68.

Harrison III, W. B., 1991, South Buckeye Field, in M. S. Wollensak, ed., Oil and Gas Field Manual ofthe Michigan Basin: Michigan Basin Geological Society, v. 2, p. 85-93.

Hinze,W. J and Merrit, D. W., 1969, Basement Rocks ofthe Southern Peninsula of Michigan, in Studies ofthe Precambrian ofthe Michigan Basin: Michigan Basin Geol. Soc. Field Excursion Guidebook, p. 28-59.

Hinze, W. J., Kellogg, R. L., and O'Hara, N.W., 1975, Geophysical Studies of Basement Geology of Southern Peninsula ofMichigan: American Association ofPetroleum Geologists, Bulletin, v. 59, p. 1562-1584.

Hitzman, M.W, 1999, Routine staining ofdrill core to determine carbonate mineralogy and distinguish carbonate alteration textures: Mineralium Deposita, v. 34, p. 794-798.

Kirschner, J. P., and Barnes, D. A, 2009, Geological Sequestration Capacity ofthe Dundee Limestone, Michigan Basin, United States, The American Association ofPetroleum Geologists/Division ofEnvironmental Geosciences, v. 16, no. 3 pp. 127-138.

James, N., 1983, ReefEnvironment, in P. Scholle, D. Bebout and C. Moore, eds., Carbonate Depositional Environments: American Association ofPetroleum Geologists, Memoir 33, p. 345-441.

Kopaska-Merkel, D. C, 1991, Analytical procedure and experimental design for geological analysis of reservoir heterogeneity using mercury porsimetry: Geological Survey ofAlabama Circular 153, p. 29.

104 Larue, D. K., 2004, outcrop and Waterflood Simulation modeling ofthe 100-Foot Channel Complex, Texas, and the Ainsa II Channel Complex, Spain: Analogs to multistory and Multilateral Channelized Slope Reservoirs, in Integration of outcrop and modern Analogs in Reservoir modeling: American Association of Petroleum Geologists, Memoir 80, p. 337-364.

Lilienthal, R.T., 1978, Stratigraphic Cross-sections ofMichigan Basin: Geological Survey Report ofInvestigations 19 Michigan Geological Survey, Lansing, 36p.

Little, C. A., 1986, Hydrodynamic Character ofthe Dundee Limestone in the Central Michigan Basin: M.S. thesis, Western Michigan University, Kalamazoo, Michigan, 84p.

Longman, M. W., 1980, Carbonate Diagenesis Texture from Nearsurface Diagenetic Environments. AAPG Bull., v. 64, p. 461487

Lucia, F.J., 1999, Carbonate Reservoir characterization: New York, Springer, 226p.

Luczaj, J. A., Harrison III, W. B., and Williams, N. S, 2006, Fractured Hydrothermal Dolomite Reservoirs in the Devonian Dundee Formation ofthe Central Michigan Basin: American Association ofPetroleum Geologists, Bulletin, v. 90, p. 1787-1801.

McCloskey, S. M., 2012, 3-D Reservoir Characterization ofthe South Buckeye Field Dundee Formation (Devonian), Michigan Basin, USA: M.S. thesis, Western Michigan University, Kalamazoo, Michigan, 386p.

Montgomery, E.L., 1986, Facies Development and Porosity Relationships in the Dundee Limestone ofGladwin County, Michigan: M.S. thesis, Western Michigan University, Kalamazoo, Michigan, 82p.

Montgomery, S. L., Wood, J. R., and Harrison III, W. B, 1998, Devonian Dundee Formation, Crystal field, Michigan Basin: Recovery ofBypassed Oil through Horizontal Drilling: American Association ofPetroleum Geologists, Bulletin, v. 82, p. 1445-1462.

Mortl, F.L., 1991, Michigan Oil and Gas Story: County by County

Noel, P. James, 1984, Reefs in Facies Models, Ed. R.G. Walker, Geological Association ofCanada, p. 229-244.

Noel, P. James., and Robert, W. Dalrymple, 2010, Peritidal Carbonate in Facies Model 4. Pratt, B. Brine, p. 401-420.

105 Pirtle, G. W., 1932,Michigan Structural Basin and Its Relationship to Surrounding Areas: American Association ofPetroleum Geologists, Bulletin, v. 16, p. 145- 152.

Plint, A.G., Eyles, N., Eyles, C.H., and Walker, R.G., 1992, Controls ofsea-level changes. In: Walker, R.J. and James, N.P. (eds.), Facies Models: Response to Sea-Level Change. Geological Association ofCanada, St. John's, Newfoundland, p. 15-25.

Prouty, C. E., 1983, The Tectonic Development ofthe Michigan Basin Intrastructures, in R. Kimmel, ed., Tectonics, Structure, and Karst in Northern Lower Michigan: Michigan Basin Geological Society 1983 Field Conference, Lansing, Michigan, p. 36-81.

Read, J. F., 1995, Overview ofCarbonate Platform Sequences, Cycle Stratigraphy and Reservoirs in Greenhouse and Icehouse Worlds, in J. F. Read, C. Kerans, and L. J. Weber, eds., Milankovitch Sea Level Changes, Cycles and Reservoirs on Carbonate Platforms in Greenhouse and Icehouse Worlds, Society ofEconomic Paleontologists and Mineralogists, Short Course 35, p. 1- 102.

Rullkotter, J., Philip A. Meyers., Schaefer, R. G, and Dunham, K. W, 1986, Oil Generation in the Michigan Basin: A biological marker and carbon isotope approach: Pergamon Journals Ltd. Org. Geochem. Vol. 10, pp. 359-375.

Sarg, J. F., 1988, Carbonate Sequence Stratigraphy, in C. K. Wilgus, B. S. Hastings, C. G. St. C. Kendall, H. W. Posamentier, C. A. Ross, and J. C. Van Wagoner, eds., Sea Level Changes: An Integrated Approach: Society ofEconomic Paleontologists and Mineralogists Special Publication No. 42, p. 155-188.

Schmoker, J.W., And Halley, R.B., 1982, Carbonate porosity versus depth: a predictable relation for south Florida: American Association ofPetroleum Geologists, Bulletin, v. 66, p. 2561-2570.

Schmoker, J.W., Krystinik, K.B. and Halley, R.B., 1985, Selected Characteristics of Limestone and Dolomite Reservoirs in the United States: AAPG Bulletin, v. 65, n. 5, p. 733-741. Scholle, P.A., And Halley, R.B., 1985, Burial diagenesis: out ofsight, out ofmind, in Schneidermann, N., and Harris, P.M., eds., Carbonate Cements: SEPM, Special Publication 36, p. 309-334.

Scholle, P. A., and Ulmer-Scholle, D. S., 2003, A Color Guide to the Petrographyof Carbonate Rocks: Grains, Textures, Porosity, Diagenesis, American Association ofPetroleum Geologists Memoir 77, 474p.

Scotese, C. R., 1984 Paleozoic Paleomagnetism and the Assembly ofPangea, In Van der Voo, R., Scotese, C. R., and Bonhommet, N., eds., Paleozoic

106 Paleomagnetism: American Geophysical Union Geodynamic Series, v.12, p.l- 10.

Shinn, E.A., 1968, Praticle Significance ofBirdseyes structures in carbonate rocks: Journal of Sedimentary Petrology, v. 38, p. 215-223.

Shinn, E.A., 1983a, Birdseyes, fenestrae, shrinkage pores, and loferites: A reevaluation, Journal ofSedimentary Petrology, v. 53, n. 2, p. 619-628.

Shinn, E.A., 1983b. Tidal flat environment, In: Scholle, P.A., Bebout, D.G., Moore, C.H., (eds.), Carbonate Depositional Environments, AAPG Memoir 33, p. 172- 210.

Strasser, A., Hillgartner, H., Hug, W. & Pittet, B., 2000, Third-order depositional Sequences Reflecting Milankovitch Cyclicity. - Terra Nova 12, 303-311

Ten Have, E. L., 1979, Relationship ofDolomite/Limestone Ratios to the Structure and Producing Zones ofthe West Branch Oil Field, Ogemaw County, Michigan: M.S. thesis, Michigan State University, East Lansing, lOOp.

Tucker, M.E. and Wright, V.P., 1990, Carbonate Sedimentology: Blackwell Science, Maiden, Massachusetts, 482 p.

Tucker, M., E., 2001, Sedimentary Petrology- an Introduction to the Origin of Sedimentary Rocks, 3rd ed., Blackwell Science Ltd., Oxford, p. 111.

Vugrinovich, R. G., and Matzkanin, A. D., 1981, Enhanced Oil & Gas Recovery in West Branch Field Dundee Oil Pool in the Michigan Basin: Secondary Recovery Report No.8.

Wallace, M. W., Kerans, C, Playford, P. E., and McManus, A., 1991, Burial diagenesis in the Upper Devonian Reef Complexes ofthe Geike Gorge Region, Canning Basin, Western Australia. American Association ofPetroleum Geologists, Bulletin., v. 75, p. 1018-1038.

Wilson, J. L, 1975, Carbonate Facies in Geologic History: Springer-Verlag Berlin, 471p.

Wood, J. R., Allan, J. R., Harrison III, W. B., and Eric Taylor, 1996, Horizontal Well Taps Bypassed Dundee oil Crystal field, Michigan: oil and gas report.

107 Appendix A Core Descriptions

108 Permits 19693 Oxy USA Inc., Mcnerney, B E13. Wise Field Isabella County Michigan Depth Interval: 3678.5' - 3717' Rogers City:

The Rogers City facies is dense, low porosity and permeability. The boundary contact between Rogers City and Dundee is marked by irregular surface (stylolite).

3678.5'-3683': Ls, dark gray, crinoidal/skeletal wackestone, Fl, occasionally interbedded with packstone, containing fossil fragments such as crinoids, gastropods, brachiopods, ostracods, and intraclasts. It has stylolite structure, has low porosity and permeability which acts as a cap rocks in the most Dundee intervals. Its contact with lower Dundee Limestone is marked by irregular surface. The depositional environment is interpreted as an open marine.

Dundee Limestone:

3683'3684': Ls, gray buff, fenestral, peloidal grainstone/packstone, F7, this facies made up largely of peloids. The skeletal grains include casts of fossil fragments, gastropods, ostracods, bivalves. Stylolites are very common in this facies, oil stain. The only sedimentary structures are fenstrae, small laminations, and cyanobacterial mat. This interval is very pores. The depositional environment is high energy peritidal.

3684'-3687.5': Ls, brown- grey, skeletal wackestone, F6, with casts of gastropods, bivalves, forams, peloids, ooids, crinoids, ostracod fragments, and calcareous sponges. No visual porosity was observed. It has stylolites and some fractures. Partially dolomitization of carbonate mud was observed. The depositional environment is low energy shallow lagoon.

3684.9', 3685.2' (Thin-section) Skeletal Wackestone. Containsforams, ostracods, bivalves. 3687.7' (Thin-section) Skeletal Wackestone it haspeloids, ooids, crinoids.

3687.5'-3692': Ls, grey buff, fenestral, peloidal grainstone/packstone, F7. Grains include peloids, with casts offossil fragments, gastropods, ostracods, bivalves. The sedimentary structures associated with this facies are fenstrae, small laminations, and cyanobacterial mat. Porosity within this facies is dominantly fenestral and interparticle, high permeability and porosity, main reservoir in

109 this field. The vugs are partially filled with calcite crystals. Stylolites are common throughout this facies, oil stain, the depositional environment is peritidal.

3688.8', 3689', 3689.3' (Thin-section)Peloidal grainstone/packstone.

3692'-3695.5': Ls, brown-gray, skeletal wackestone F6, skeletal grains include gastropods, bivalves, ostracod fragments, forams, and minor stromatoporoids. No visual porosity. The stylolites and some fractures are observed. The depositional environment is interpreted as a low energy lagoon.

3693.1' (Thin-section) Skeletal Wackestone.

3695.5'3698': Ls, grey buff, fenestral, peloidal grainstone/packstone, F7. This interval is largely made of peloids, and with casts of fossil fragments, gastropods, ostracods, bivalves. The sedimentary structures associated with this facies are fenstrae and small laminations, and cyanobacterial mat. Porosity within this facies is dominantly fenestral and interparticle, main reservoir in this field. The vugs are partially filled with calcite crystal cement. Stylolites are common throughout this facies, oil stain and the depositional environment is interpreted as peritidal

3698'-3700': Ls, brown-gray, very fined grain, skeletal wackestone, F6 with casts of gastropods and ostracod fragments. No visual porosity, it has stylolites and some vertical fracture (5-8cm). The depositional environment is low energy lagoon.

3700'3709.5': Ls, gray buff, fenestral, peloidal grainstone/packstone, F7. This facies consist of peloids, gastropods, ostracods, bivalves. This interval is very porous. The sedimentary structures associated with this facies are fenstrae and small laminations, and cyanobacterial mat. Porosity within this facies is dominantly fenestral and interparticle porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement. Stylolites are common throughout this facies, oil stain, and the depositional environment is peritidal.

3700.8' (Thin-section) Peloidal grainstone

3709.5'-3711': Ls, gray buff, skeletal wackestone, F6, fined grained, fossil fragments, bivalves, gastropods, ostracods, forams and ooids??. The stylolites have bladed dolomite along vertical lines. This interval has low permeability and porosity.

3709.3' (Thin-section) skeletal wackestone.

110 3711'-3714.5': Ls, grey buff, fenestral, peloidal grainstone/packstone, F7, mainly made up of peloids, and with casts of fossil fragments, gastropods, ostracods, bivalves. The sedimentary structures associated with this facies are fenstrae and small laminations, and cyanobacterial mat. Porosity within this facies is dominantly fenestral and interparticle porosity, main reservoir in this field. Stylolites are common throughout this facies, oil stain, and the depositional environment is peritidal.

3712'-13' (Thin-section) fenestralpeloidal grainstone.

3714.5'-3717': Ls, brownish gray, very fined grain, skeletal wackestone, F6, skeletal garains include gastropods, ostracod fragments, forams very abundant. Sparse vugy and moldic porosity that partially filled with calcite cements, stylolites are very common. The depositional environment is low energy lagoon.

3716.6' (Thin-section) Skeletal Wackestone.

Ill Permit#35461 Oryx Energy Co., Sierra Land CO., INC 1, Mt Pleasant Midland County Michigan Depth Interval: 3530'-3615'

Rogers City:

3530'-3544': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

3544'-3554': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure. Porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field.

3554'-3556': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3560'-3563': Missing interval.

3563'-3565': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3565'-3569': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3569'-3570.5': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

112 3570.5'-3574': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3574'-3577': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid) at 3680'. No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3577'-3579': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and allochems grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure.

3579'-3581': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3581' -3584.5': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the skeletal grains include coral and sponges fragments. The main sedimentary structures are tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3584.5'-3585.5: Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3585.5-3588': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir

113 in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3588'-3590': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3590'-3594': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite.

3594'-3598': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3598'-3607': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3607'-3610': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3610'-3615': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, the depositional environment is peritidal

♦ This core was depth-shifted up 5 feet to match the wire-line logs

114 Permit#35764 Oryx Energy Co., Ames, C W 1, Mt Pleasant Midland County Michigan Depth Interval: 3530'-3595'

Rogers City:

3530'-3534': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

3534'-3543': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field. This facies has been deposited in peritidal environment.

3543'-3545': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3545' -3548': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3548'-3550': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3550'-3557': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir

115 in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3557'-3560': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3560'-3568': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3568'-3573': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3573'-3577': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3577'-3579': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3579'-3584': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

116 3584'-3587': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3587'-3589': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3589'-3595': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

117 Permit#36227 Oryx Energy Co., Sokolowski, C T 1, Mt Pleasant Midland County Michigan Depth Interval: 3544'-3609' Dundee Limestone:

3544'-3548': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure. Porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field.

3548'-3551': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3551' -3561': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the skeletal grains include coral and sponges fragments. The main sedimentary structures are tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3561'-3563': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3563'-3573': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3573'-3574': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3574'-3585': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure.

118 Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3585'-3587': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3587'-3591': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3591'-3597': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with castsof bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3597'-3600: Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and allochems grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure.

3600'-3601': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3601' -3603': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the skeletal grains include coral and sponges fragments. The main sedimentary structures are tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

119 3603'-3604': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3604'-3609': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

120 Permit#36259 Oryx Energy Co., Pfund-1, Mt Pleasant Midland County Michigan Depth Interval: 3525'-3660'

Rogers City:

3525'-3539': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

3539'-3553': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3553'-3555': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3555'-3563': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. This facies was deposited in peritidal environment.

3563'-3565': Limestone, light to brownish gray Ls, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3565'-3569': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity

121 within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field3569'-3571': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3571'-3579' Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic with minor stylolitic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal

3579'-3581': Ls, light to brownish gray, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). This facies interpreted as storm deposit. Stylolite structure is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3581'-3583': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include brachiopods, coral, sponges fragments, stromatoporoid rich. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic with minor stylolitic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3583'-354.5: Limestone, light to brownish gray Ls, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid it about 10 cm). This facies interpreted as storm deposit. Wispy and suture stylolites is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3584.5'-3587': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments, stromatoporoid. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field.

122 The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3587'-3589': Limestone, light to brownish gray Ls, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid it about 10 cm). This facies interpreted as storm deposit. Stylolite structure is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3589'-3604': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments and stromatoporoid rich at 3598'-3600'. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3604'-3606.5': Ls, light to brownish gray, skeletal wackestone, F6, very fine grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges. This facies interpreted as storm deposit. Stylolite structure is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3606.5'-3634': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments, stromatoporoid at 3642.5' (12cm). The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3634'-3636': Ls, light to brownish gray, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges. This facies interpreted as storm deposit. Wispy and suture stylolites is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3636-3639': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments. The sedimentary structures found in this facies include

123 small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3639'-3644': Ls, light to brownish gray, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges. This facies interpreted as storm deposit. Wispy and suture stylolites is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3644'-3650': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral brachiopods and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic with minor stylolitic porosity, high permeability and porosity, main reservoir in this field. This facies interpreted as peritidal environment.

3650'-3652': Ls, light to brownish gray, skeletal wackestone, F6, very fine-grained, with casts of bivalves, ostracod fragments, coral and calcareous sponges. This facies interpreted as storm deposit. Wispy and suture stylolites is common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

3652'-3657': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment. Flooding surface @3652.5-3654(diverse fauna include crinoids and finger coral, sponges, and stromatoporoid debris)

124 Permit#36367 Oryx Energy Co., Mcclintic-3, Mt Pleasant Isabella County Michigan Depth Interval: 3570'-3640'

Rogers City:

3570'-3576': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

3576'-3581': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field. This facies has been deposited in peritidal environment.

3581'-3583': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3583' -3593': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3593'-3596': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3596'-3599': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir

125 in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3599'-3601': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3601'-3603': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3603'-3604': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3604'-3607': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, , the depositional environment is peritidal.

3607'-3609': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3609'-3614': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

126 3614'-3617': Limestone, light to brownish gray Ls, skeletal wackestone, F6, it is highly bioturbated with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3617'-3625': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3625'-3627': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3627'-3631': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3631'-3636': Limestone, light to brownish gray Ls, skeletal wackestone, F6, it is highly bioturbated with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3636'-3640': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

♦ This core was shifted up 5 feet.

127 Permit#36387 Oryx Energy Co., Miller, Viola 1, Mt Pleasant Isabella County Michigan Depth Interval: 3560'-3630'

Rogers City:

3560'-3588: Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

3588'-3594': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field. This facies has been deposited in peritidal environment.

3594'-3598': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3598' -3606': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3606'-3614': Missing interval.

3614'-3616': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3616'-3618': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral

128 structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3618'-3620': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

3620'-3623': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

3623'-3626': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon.

3626'-3630': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal.

129 Permit#39770 Oryx Energy Co., Mt Pleasant Unit Tract 55 Isabella County Michigan Depth Interval: 3557' - 3617'

Rogers City:

3557'-3572': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, minor bivalves, trilobites, fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

3574.4' (Thin-section) Crinoidal wackestone.

Dundee Limestone:

3572'-3577': Ls, light to brownish gray, fenestral peloidal grainstone/ packstone, F7, and the grains within this facies includes peloids and sparsely gastropods and bivalves, trilobites, and other fossil fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, main reservoir in this field. The depositional environment is peritidal.

3575' (Thin-section) peloidalpackstone

3577'-3579': Ls, light to brownish gray, skeletal wackestone, F6, with casts of gastropods, bivalves, forams, peloids, crinoids, ostracod fragments, and calcareous sponges (stromatoporoid) at 3578'. No Visual vugy porosity, it has stylolites and some fractures. Partially dolomitization of carbonate mud. The depositional environment is interpreted as a low energy shallow lagoon.

3579' -3590': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, this interval occasionally interbedded with skeletal wackestone at 3584', grains within this facies includes mainly peloids and sparsely gastropods and bivalves, trilobites, and other fossil fragments. Porosity within this facies is dominantly fenestral, moldic and interparticle porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure common throughout the core. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure, the depositional environment is peritidal.

3585.9', 3589.1' (Thin-section) peloidal grainstone

130 3590'-3593': Ls, light to brownish gray, skeletal wackestone, F6, consist of gastropods, ostracods, bivalves, trilobites. Low porosity and permeability, stylolites are very common throughout the core.

3592.2' (Thin-section) skeletal wackestone

3593'-3597': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, grains includes mainly peloids and sparsely gastropods and bivalves. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and interparticle porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal.

3593.9' (Thin-section)peloidal grainstone

3597'-3600': Ls, light to brownish gray, skeletal wackestone, F6, consists of gastropods, ostracods, bivalves, and trilobites and corals, stylolites, no visual porosity. The depositional environment is low energy shallow lagoon.

3597.9' (Thin-section) skeletal wackestone

3600'-3607': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, the grains present in this facies include mainly peloids and sparsely gastropods and bivalves, ostracods, trilobites. Porosity within this facies is dominantly fenestral and moldic porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure common throughout the core. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure, the depositional environment is peritidal.

3607'-3610': Ls, light gray, skeletal wackestone, F6, consists of gastropods, ostracods, bivalves, trilobites, and peloids. Low porosity and permeability, calcite cements, it has stylolite and vertical fractures at 3609'. The depositional environment is low energy shallow lagoon.

3606' (Thin-section) skeletal wackestone

3610'-3616' Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and grains include mainly peloids and sparsely gastropods and bivalves, ostracods, trilobites. Porosity within this facies is dominantly fenestral and interparticle, forms a main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure common throughout the core. The sedimentary structures found in this facies include small cyanobacterial

131 mats, tidal laminations, and fenestral structure, the depositional environment is peritidal.

3610.5' (Thin-section) peloidalpackstone

3616'-3617': Ls, light to brownish gray, skeletal wackestone, F6, very fine-grained, consist of gastropods, ostracods, bivalves, peloids, and trilobites, stylolite structure are common, no visual porosity. Low porosity and permeability based on the core analysis date. The depositional environment is low energy shallow lagoon.

♦ This core was shifted up 3 feet

132 Permit#39771 Oryx Energy Co., Mt Pleasant Unit Tract 46, Mt Pleasant Isabella County Michigan Depth Interval: 3567'-3627'

Rogers City: 3567'-3582': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists of crinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment. Dundee Limestone: 3582'-3588': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, and forms a main reservoir in this field. This facies has been deposited in peritidal environment. 3588'-3590': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No visual porosity, it has stylolites and some fractures. The depositional environment is low energy shallow lagoon. 3590' -3595': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal. 3595'-3597': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon. 3597'-3606': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure observed in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal. 3606'-3608': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

133 3608'-3611': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structure found in this facies is fenestral structure. Very fine to fine sand grain, porosity within this facies is dominantlyfenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The depositional environment is peritidal. 3611'-3614': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). This facies is u interbedded with peloidal grainstone facies #7. It has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon. 3614'-3617': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, , the depositional environment is peritidal. 3617'-3621': Ls, light to brownish gray, skeletal wackestone, F6, it is highly bioturbated with casts ofbivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon. 3621'-3625': Ls, light to brownish gray, fenestral peloidal grainstone/packstone, F7, and the observed grains within this facies include coral and sponges fragments. The sedimentary structures found in this facies include, tidal laminations, and fenestral structure very limited. Very fine to fine sand grain, porosity within this facies is dominantly fenestral and moldic porosity, high permeability and porosity, main reservoir in this field. The vugs are partially filled with calcite crystal cement, stylolite structure, the depositional environment is peritidal. 3625'-3627': Limestone, light to brownish gray Ls, skeletal wackestone, F6, it is highly bioturbated with casts of bivalves, ostracod fragments, and calcareous sponges (stromatoporoid). No Visual porosity, it has low and high amplitude stylolites and some fractures, oil stain. The depositional environment is low energy shallow lagoon. ♦♦♦ This core was shifted up 8 feet.

134 Permit # 36730 Summit Petroleum Corp., Fitzwater 6. South buckeye Field Gladwin County Michigan Depth Interval: 3560'-3624' Rogers City:

3560'-3562': Ls, dark gray, crinoidal/skeletal wackestone, Fl, contains crinoids, bryozoans, brachiopods, ostracods, undifferentiated fossils, intraclasts, small fractures filled with calcite cement. It has stylolite structure and has very low porosity and permeability according to the core analysis which acts as cap rocks in the most Dundee intervals.

Dundee Limestone:

3562'-3564': Burrowed peloidal grainstone/packstone, F2. This facies is observed on top of the Dundee just below the Rogers City. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components ofthis facies. Wispy and suture stylolites are common throughout this facies. It is commonly fine to medium-grained and moderately sorted. The major porosity types include interparticle, intraparticle porosity. It is a non- reservoir facies due to its low porosity and permeability.

3563' (thin-section)peloidal grainstone/packstone

3564'-3670.5': Ls, gray-brownish gray, stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Minor intercalations of crinoidal grainstone and skeletal peloidal grainstone are occasionally associated with this facies. Stylolites are common throughout this facies. Porosity of this facies includes growth framework, vuggy, and intraparticle porosity and also some interparticle porosity in the grainstone facies. It is the main reservoir in South Buckeye field.

3565' (thin-section) StromatoporoidBoundstone

3570.5'-3572.5: Ls, brownish gray, crinoidal grainstone, F3, consists of crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. It is very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Wispy and suture stylolites. Porosity of this facies includes intraparticle and interparticle and moldic porosity (interpreted as a secondary reservoir facies).

135 3571' (thin-section) Crinoidal Grainstone

3572.5'-3590.5': Ls, gray-brownish gray, stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Minor intercalations of crinoidal grainstone and skeletal peloidal grainstone are occasionally associated with this facies. Porosity ofthis facies includes growth framework, vuggy, and intraparticle porosity and also some interparticle porosity in the grainstone facies.

3587' (thin-section) StromatoporoidBoundstone

3590.5'-3600': Burrowed peloidal grainstone/packstone F2. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. Stylolites are common throughout this facies. It is commonly fine to medium-grained and moderately sorted. The major porosity types include interparticle, intraparticle porosity. It is a non-reservoir facies due to its low porosity and permeability.

35793' (thin-section) peloidal grainstone/packstone

3600'-3602': Crinoidal grainstone, F3, consist of crinoids, peloids, bivalves, trilobites, ostracods. It is very fine-grained and moderately sorted. Wispy and suture stylolites. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle porosity and also some interparticle and moldic porosity (interpreted as a secondary reservoir facies).

3602'-3608.5': Burrowed peloidal grainstone/packstone, F2. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. It is commonly fine to medium- grained and moderately sorted. This facies is interbedded with the stromatoporoid boundstone facies at 3610' and also the crinoidal grainstone facies. Stylolites are common throughout this facies. The major porosity types include interparticle, intraparticle porosity. It is a non-reservoir facies due to its low porosity and permeability.

3608.5'-3610.5' Coral-stromatoporoid rudstone/rudstone, F4. This facies varies from fine to medium-grained, well sorted, with skeletal graindebris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, sponges, and

136 stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle.

3609' (thin-section) ReefFlank

3610.5'-3617': Burrowed peloidal grainstone/packstone, F2. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. It is commonly fine to medium-grained and moderately sorted. This facies is interbedded with the stromatoporoid boundstone facies at 3610' and also the crinoidal grainstone facies. Stylolites are common throughout this facies. The major porosity types include interparticle, intraparticle porosity. It is a non-reservoir facies due to its low porosity and permeability

3617'-3624': Crinoidal grainstone, F3, consists of crinoids, peloids, bivalves, trilobites, ostracods. It is very fine-grained and moderately sorted. Wispy and suture stylolites. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Stylolites are common throughout this facies. About foot or so there is fining up sediments which indicate to a storm deposit (at 3620'). Porosity of this facies includes intraparticle, interparticle, intercrystalline porosity (interpreted as a secondary reservoir facies).

3623' (thin-section) Crinoidal Grainstone 3624' (thin-section) Crinoidal Grainstone

137 Permit# 43383 Summit Petroleum Corp., Nusbaum Kern 3-W. South buckeye Field Gladwin County Michigan Depth Interval: 3526'-3686' Rogers City:

3526'-3547': Ls, dark gray, crinoidal/skeletal wackestone, Fl, contains crinoids, bryozoans, brachiopods, ostracods, undifferentiated fossils, intraclasts, small fractures filled with calcite cement. It has stylolite structure and has very low porosity and permeability according to the core analysis which acts as cap rocks in the most Dundee intervals.

353 7.4' (thin-section) Crinoidal wackestone

Dundee Limestone:

3547'-3552': Burrowed peloidal grainstone/packstone, F2, this facies is observed on top of the Dundee just below the Rogers city. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. It is commonly fine to medium-grained and moderately sorted. The major porosity types include interparticle, intraparticle porosity. It is a non-reservoir facies due to its low porosity and permeability.

3548.9 (thin-section)peloidal grainstone/packstone

3552'-3554' Coral-stromatoporoid rudstone/rudstone, F4. This facies varies from fine to medium-grained, well sorted, with skeletal grain debris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, sponges, and stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle.

3554'-3662': Ls, gray - brownish gray, stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Occasionally interbedded with crinoidal skeletal grainstone facies at 3570', 3571', and 3576'. Porosity of this facies includes growth framework, vuggy, and intraparticle porosity and also some interparticle porosity. It is the main reservoir facies.

3562'-3563: Ls, brownish gray, crinoidal grainstone, F3, consist of, crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. Very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Wispy and suture stylolites

138 are common. Porosity of this facies includes intraparticle interparticle intercrystalline porosity (interpreted as a secondary reservoir facies).

3562' (thin-section) Crinoidal Grainstone

3563'-3667.3': Ls, gray - brownish gray, stromatoporoid boundstone, F5, the skeletal grains within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Porosity of this facies includes growth framework, vuggy, and intraparticle porosity and also some interparticle porosity.

3564.4' (thin-section) Stromatoporoid Boundstone.

3577.3'-3573': Burrowed peloidal grainstone/packstone, F2. This facies is observed on top of the Dundee just below the Rogers City. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. It is commonly fine to medium- grained and moderately sorted. The major porosity types include interparticle, intraparticle, limited distribution of vuggy, moldic, and intercrystalline porosity. It is a non-reservoir facies due to its low porosity and permeability.

3569.9' (thin-section) peloidal grainstone/packstone

3573'-3582': Crinoidal grainstone, F3, consist of crinoids, peloids, bivalves, trilobites, ostracods. It is very fine-grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle, and interparticle porosity (interpreted as a secondary reservoir facies).

3574.7' (thin-section) Crinoidal Grainstone

3582'-3586': Burrowed peloidal grainstone/packstone, F2. This facies is observed on top of the Dundee just below the Rogers City. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present in the skeletal peloidal grainstone facies. Peloids are observed as major components of this facies. It is commonly fine to medium-grained and moderately sorted. The major porosity types include interparticle, intraparticle, and intercrystalline porosity. 3583.5' (thin-section) peloidal grainstone/packstone ♦ This core was shifted up 10 feet

139 Permit#32780 Summit Petroleum Corp., State Buckeye B-6, North Buckeye Field Gladwin County Michigan Depth Interval: 3589' - 3667' Rogers City:

3589'-3609.5': Ls, dark grey, Crinoidal/ Skeletal wackestone Fl, contain fossil fragments such as crinoids, gastropods, brachiopods, ostracods, and intraclasts. Small fractures filled with calcite cements, the depositional environment is open marine (subtidal). It has stylolite structure and has very low porosity and permeability according to the core analysis which acts as cap rocks in the most Dundee intervals.

3602.8' (Thin-section) crinoidal wackestone.

Dundee Limestone:

3609.5'-3643': Ls, buff to tan, fenestral peloidal grainstone/packstone, F7, very fine grained, and moderately sorted, fenestrae dominant and oil stained. This facies is largely made up of peloids. Skeletal grains within this facies include brachiopods, bivalves, ostracods, gastropods, crinoids, stromatoporoids at 3635, and corals rich at 3646.5. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure (vertical and horizontal fenestrae), stylolite structures. Porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field.

3616. '2, 3620.8', 3629.6' (Thin-section) Fenestralpeloidalpackstone

3637.6' (Thin-section) skeletal wackestone

3643'-3646': Ls, brown- gray, skeletal wackestone, F6, with casts of gastropods, bivalves, forams, peloids, ooids, crinoids, ostracod fragments, and calcareous sponges. No Visual porosity was observed. It has stylolites and some fractures. Partially dolomitization of carbonate mud was observed. The depositional environment is low energy shallow lagoon.

3646'-3656': Coral-stromatoporoid rudstone/rudstone, F4. This facies varies from fine to medium-grained, well sorted, with skeletal grain debris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, and stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle with a minor intercrystalline component.

3649.6' (Thin-section) skeletal trilobite wackestone

140 3651' (Thin-section) crinoidal skeletal grainstone

3656'-3666': Stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Occasionally interbedded with crinoidal skeletal grainstone facies. Porosity of this facies includes growth framework, vuggy, and intraparticle and also some interparticle porosity in the grainstone facies, fractures augment, moderate to high porosity/permeability. Main reservoir in South Buckeye field.

3656.6', 3660' (Thin-section) stromatoporoid boundstone: consists of crinoids, brachiopods, bryozoans, corals, and trilobites. Growth framework porosity occurs.

3663' (Thin-section) skeletal grainstone: consists of, crinoids, and brachiopods, corals, and trilobites.

3666'-3667': Ls, very dark gray, Coral-stromatoporoid rudstone/rudstone, F4. This facies varies from fine to medium-grained, well sorted, with skeletal grain debris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, and stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle with a minor intercrystalline component.

♦ This core was shifted up 6 feet

141 Permit#52002 Summit Petroleum Corp., Salla, John 9-11 HD, North Buckeye Field Gladwin County Michigan Depth Interval: 3598' - 3658' Rogers City:

3598'-3599: Ls, dark grey, Crinoidal/ Skeletal wackestone Fl, contains fossil fragments such as crinoids, gastropods, brachiopods, ostracods, and intraclasts. Small fractures filled with calcite cements, the depositional environment is open marine (subtidal). It has stylolite structure and has very low porosity and permeability according to the core analysis which acts as cap rocks in the most Dundee intervals.

Dundee Limestone:

3599'-3624': Ls, buff to tan, fenestral peloidal grainstone/packstone, F7, very fine grained, and moderately sorted, fenestrae dominant and oil stained. This facies is largely made up of peloids. Skeletal grains within this facies include brachiopods, bivalves, ostracods, gastropods, crinoids, and stromatoporoids. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure (vertical and horizontal fenestrae), stylolite structures. Porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field.

3624'-3625.5': Ls, brown- gray, skeletal wackestone, F6, with casts of gastropods, bivalves, forams, peloids, ooids, crinoids, ostracod fragments, and calcareous sponges. No Visual porosity was observed. It has stylolites and some fractures. Partially dolomitization of carbonate mud was observed. The depositional environment is low energy shallow lagoon.

3625.5'-3633': Missing interval

3633'-3644': Ls, buff to tan, fenestral peloidal grainstone/packstone, F7, very fine grained, and moderately sorted, fenestrae dominant and oil stained. This facies is largely made up of peloids. Skeletal grains within this facies include brachiopods, bivalves, ostracods, gastropods, crinoids, and stromatoporoids. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure (vertical and horizontal fenestrae), stylolite structures. Porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field.

3644'-3646': Ls, brown- gray, skeletal wackestone, F6, with casts of gastropods, bivalves, forams, peloids, ooids, crinoids, ostracod fragments, and calcareous sponges. No Visual porosity was observed. It has stylolites and some fractures.

142 Partially dolomitization of carbonate mud was observed. The depositional environment is low energy shallow lagoon.

3646'-3650': Coral-stromatoporoid rudstone/rudstone, F4. This facies varies from fine to medium-grained, well sorted, with skeletal grain debris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, and stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle with a minor intercrystalline component.

3650'-3656': Stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Occasionally interbedded with crinoidal skeletal grainstone facies. Porosity of this facies includes growth framework, vuggy, and intraparticle and also some interparticle porosity in the grainstone facies, fractures augment, moderate to high porosity/permeability. Main reservoir in South Buckeye field.

3656'-3658': Ls, buff to tan, fenestral peloidal grainstone/packstone, F7, very fine grained, and moderately sorted, fenestrae dominant and oil stained. This facies is largely made up of peloids. Skeletal grains within this facies stromatoporoids. The sedimentary structures found in this facies include small cyanobacterial mats, tidal laminations, and fenestral structure (vertical and horizontal fenestrae), stylolite structures. Porosity within this facies is dominantly fenestral porosity, high permeability and porosity, main reservoir in this field.

♦> This core was shifted up 5 feet

143 Permit#35720 Jordan Energy Exploration Co Lie, Hutsonl-2., Butman Gladwin County MI Depth Interval: 3656'-3686' Rogers City:

The Rogers City facies is dens, grey-dark gray Ls, low porosity and permeability. The boundary contacts between the Rogers City and Dundee is marked by irregular surface (stylolite).

3656-3674.5 Limestone, gray-dark gray Ls, crinoidal/skeletal wackestone, Fl, fine to medium-grained muddy packstone with burrows, bivalves, corals, intraclasts, suture stylolites, chert nodules, no visual porosity. Intercalated with crinoidal bioturbated packstone at 3660.3-62, 3664-65. This facies representing open marine environments.

Dundee Limestone

3674.5-3686: Ls, gray-brownish gray, stromatoporoid boundstone, F5. Bioclasts within this facies include massive and tabular stromatoporoids, corals, brachiopods, crinoids, bryozoans, and trilobites. Minor intercalations of crinoidal grainstone and skeletal peloidal grainstone are occasionally associated with this facies. Stylolites are common throughout this facies. Porosity of this facies includes growth framework, vuggy, and intraparticle porosity and also some interparticle porosity in the grainstone facies. It is representing a good reservoir based on the Neutron porosity log.

144 Permit#28399 DEVELOPMENT CO., Grow 4, West Branch Ogemaw CO, MI Depth Interval: 2540' - 2716' Rogers City:

2540'-2573.5': Ls dark gray, crinoidal/skeletal wackestone, Fl, consists ofcrinoids, and other fossil fragments, intraclasts, has stylolite structure and has very low porosity and permeability, which act as cap rocks in the most Dundee intervals. This facies representing open marine environment.

Dundee Limestone:

2573.5'-2582': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

2582'-2591': Ls, light to brownish gray, burrowed peloidal grainstone/packstone, F2, this facies is observed on top of the Dundee just below the Rogers city. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present. Peloids are observed as major components of this facies. It is commonly medium to fine-grained and moderately sorted. Wispy and suture stylolites, oil stained. This facies was deposited in protected shallow marine environment.

2591'-2616': Ls, brownish gray, crinoidal grainstone, F3, consist of, crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. Very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle, interparticle, and moldic porosity (interpreted as a secondary reservoir facies).

2616'-2625': Ls, light to brownish gray, burrowed peloidal grainstone/packstone, F2, this facies is observed on top of the Dundee just below the Rogers city. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present. Peloids are observed as major components of this facies. It is commonly medium to fine-grained and moderately sorted. Wispy and suture stylolites, oil stained. This facies was deposited in protected shallow marine environment.

145 2525'-2648': Ls, brownish gray, crinoidal grainstone, F3, consist of, crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. Very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle, interparticle, and moldic porosity (interpreted as a secondary reservoir facies).

2648'-2652': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

2652'-2662': Ls, brownish gray, crinoidal grainstone, F3, consist of, crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. Very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle, interparticle, and moldic porosity (interpreted as a secondary reservoir facies).

2662'-2670': Ls, light to brownish gray, burrowed peloidal grainstone/packstone, F2, this facies is observed on top of the Dundee just below the Rogers city. The skeletal grains of this facies include brachiopods, crinoids, bivalves, ostracods, trilobites, bryozoans, corals, and phylloid algae. Burrows are the only sedimentary structure present. Peloids are observed as majorcomponents of this facies. It is commonly medium to fine-grained and moderately sorted. Wispy and suture stylolites, oil stained. This facies was deposited in protected shallow marine environment.

2670'-2682': Ls, brownish gray, crinoidal grainstone, F3, consist of, crinoids, peloids, bivalves, trilobites, ostracods, bryozoans, brachiopods. Very fine grained and moderately sorted. The crinoidal grainstone facies is usually found below the stromatoporoid boundstone facies and sometimes it is interbedded with burrowed skeletal peloidal grainstone facies. Porosity of this facies includes intraparticle, interparticle, and moldic porosity (interpreted as a secondary reservoir facies).

2682'-2704': Ls, light to brownish gray, coral-stromatoporoid rudstone F4. This facies varies from fine to medium-grained, well sorted, with skeletal grain debris consisting of crinoids, bivalve, brachiopods, finger and tabulate corals, sponges, and stromatoporoid fragments, were deposited in grainy or muddy matrix. Porosity type within this facies is predominantly intraparticle and interparticle.

146 2704'-2716': Ls, light to brownish gray, skeletal wackestone, F6, with casts of bivalves, ostracod fragments, coral and calcareous sponges (stromatoporoid). Wispy and suture stylolites and some fractures. The depositional environment is low energy shallow lagoon.

147 Appendix B

Core Descriptions Charts and Graphics

148 LEGEND Grain Types, sedimentary Structures, and Porosity Types

fff Stylolitic 000 Peloids (| Burrowed -^ Crinoids =00: Fenestral Textures BC Intercrystalline Porosity

•r$fi/ Brachiopod BP Interparticle Porosity A Gastropod WC Intracrystalline Porosity

/^J Stromatoporoid \Yp Intraparticle Porosity

\f Brvozoan PW Framework Porosity

@ Coral MO Moldic

^^ Undifferentiated Fossils VUG Vug

-Dundee-Rogers City contact Thin Section

Total Depth Limestone

Idealized Vertical Succession of Seven Facies Fenestral Peloidal Grainstone/Packstone (Peritidal)

Skeletal Wackestone (Lagoonal)

F5 Stromatoporoid Boundstone (Patch reef)

Coral-stromatoporoid (loatstone to rudstone (Reef Flank)

F3 Crinoidal Grainstone (Shoal)

Bioturbated Peloidal Grainstone/Packstone (Protected shallow marine)

Crinoidal/Skeletal Wackestone (Open marine)

149

Permit # 35461 Oryx Energy Co., Sierra Land CO., INC 1, MT Pleasant, Midland CO, Ml Formation: Dundee Limestone Depth Interval: 3530'-3615'

151

Permit # 36259 Oryx Energy Co., Pfund-1, MT Pleasant, Midland CO, Ml Formation: Dundee Limestone Depth Interval: 3525'-3695'

156 Dundee Formation I X "tLJJJJJSJJJL Mi I I I I1?! I I l¥l II Ifl II If III I?! 1 1 I Oil Staining Thin Sections Lagoonal Peritidal Lagoonal Pehtidal Depositional Environment Facies Type

|i|i|i|iii|i|i|i|i|i|i|i|iii|i|iil|il Lithology lllllllllllllllllllllllllllllllllllll

^1 Dundee Formation x 3| fJJ ifi II if i I I if i i i if i i i if i i i Lgj i i iMi i i Lfgj i i L§

oo Permit # 36367 Oryx Energy Co., Mcclintic-3, MT Pleasant, Isabella CO, Ml Formation: Dundee Limestone Depth Interval: 3570'-3640'

159

Dundee RGRC Fomiation ~JT i o fl I I?! I I If' I I If I I I IT i i iin If I I i i i i IS U_L I I I I J_LL •t-1 5>" Oil Staining x Thin Sections m I Peritidal Lagoonal Peritidal Peritidal Peritidal Open Marine Depositional Envii'onment CO Facies Type o o

Permit # 43383 Summit Petroleum Corp., Nusbaum Kern 3-W, S Buckeye, Gladwin CO, Ml Formation: Dundee Limestone Depth Interval: 3525'-3586'

166 Permit #32780 Summit Petroleum Corp., State Buckeye B-6, N Buckeye, Gladwin CO, Ml Formation: Dundee Limestone Depth Interval: 3589'-3667'

167

Permit #52002 Summit Petroleum Corp., Salla, John 9-11 HD, N Buckeye, Gladwin CO, Ml Formation: Dundee Limestone Depth Interval: 3598'-3658'

*This corewasShifted up5 ft]

169 Permit # 28399 MUSKEGON DEVELOPMENT CO., Grow 4, West Branch, Ogemaw CO, Ml Formation: Dundee Limestone Depth Interval: 2540'-2715'

170

^1 to

Permit # 35720 Jordan Energy Exploration CO LLC, Huston 1-2., Butman. Gladwin CO, Ml Formation: Dundee Limestone Depth Interval: 3656'-3686'

174 Appendix C Core Photographs

175 [McNerney,BE3,3682.8'

%jP *• *

^ 03

>""-' o

• tkWmm\ Os DUNE

1i - * ~" W

U •v*" >- 1 •j&P':*^,-"•'

FigureC.l. Crinoidalskeletalwackestonefacies #1. (A) Corephotograph,mudnodulartexture (Nod)rangingfrom1-2cm in diameter. (B) Slabbed core photograph showing thecontact between theupper Rogers City (RGRC) and the lower Dundee Limestone (DUND),separated bymineralized stylolite (Sty). (C) Slabbed core photograph, showing crinoid-rich (Cri). FigureC.2.Bioturbatedpeloidalgrainstone/packstonefacies # 2. (A) Corephotograph,showingthe burrowed(Bur). ^1 oc

Figure C.3. Slabbed core photographsofthe crinoidal grainstone facies # 3. yNusbaijm Kern 3-W, 3563'

u I

'••;.,.

;:3fcr * i &H v #

* ^» '• < » «- *-« 1. •> = ~1VWing•cjjfW " : • •*.

Mr * a Gi

--0 um^j^^~* tI SO

^-BhBhE "i.

• -^B|~n •

• - ^ -*** •'. ""imitf

Figure C.4. Reefflank facies # 4 core photographs, showing ripped up andre-deposited stromatoporoids (Strom), crinoids (Cri), and bryozoans (Bry) on a reef flank. oo o

Figure C.5. Patch reeffacies # 5, core photographs of stromatoporoid boundstone showing pillar and lamina structure (yellow arrows). oo

FigureC.6. Skeletalwackestonefacies# 6. (A)Corephotographofskeletalwackestonefaciesassociatedwith stylolites (Sty) and fractures (Fr). State Buckeye, 3616'

00 to

Figure C.7. Core photographs display fenestral peloidal grainstone/packstone facies # 7 from three fields (Wise, Mt Pleasant, North Buckeye fields). Appendix D Conventional Core Analysis Dundee Limestone Formation

183 Permit U 19693 Mcnerney, B E 3, Wise Field, Isabella County Michigan

DC X _i LU z O LU 1- Z X LU 0 O o < Q i X i o 1- 1- o < Q_ OL 0) CO LU CO < Q s o 9 CO o LU % CO Q CO Q. LU z LU O _J LU Q_ u. Q _l Q u.

3687.5 0.4 6.3 8.3 33.3 3688.5 9.3 6.7 7.7 38.5 3689.5 0.0 6.3 TR 33.3 3690.5 0.2 6.0 TR 43.3 3691.5 0.0 6.3 TR 41.0 3692.5 0.0 6.6 TR 38.9 3693.5 0.0 4.2 TR 62.9 3696.5 0.1 5.5 10.3 77.0 3697.5 TR 4.5 11.5 75.0 3698.5 1.0 8.8 TR 20.3 3699.5 TR 4.2 TR 68.6 3700.5 0.2 6.1 0.0 30.2 3701.5 TR 5.4 TR 33.8 2702.5 TR 5.5 TR 48.3 2703.5 TR 9.8 5.2 23.5 2705.5 0.0 6.8 0.0 34.9 3706.5 0.0 5.6 9.3 74.5 3707.5 0.0 3.4 0.0 61.5 3708.5 3.9 5.0 0.0 36.6 3712.5 0.0 3.2 16.5 66.0 3714.5 0.0 5.3 0.0 79.6 3715.5 0.0 7.1 TR 65.4 3718.5 0.2 10.8 9.4 25.9 3719.5 0.7 7.7 6.8 33.8 3720.5 TR 4.5 TR 76.0 3723.5 TR 3.8 TR 70.5

184 Permit#35461 Sierra Land CO., INC 1, Mt Pleasant Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3536 0.03 0.01 1.0 14.6 29.2 2.70 LM,SL/SHY,SHLAM,STY 3537 0.03 0.03 1.3 9.9 49.6 2.68 LM,SHY,FOSS,STY 3538 0.06 0.06 1.8 11.2 45.0 2.71 LM.SHY.SH- 3539 0.05 0.03 1.8 6.6 39.9 2.71 LM 3540 0.05 0.01 1.3 5.9 29.7 2.70 LM,SL/SHY,FOSS,STY 3541 0.02 0.02 0.5 11.0 43.9 2.70 LM,SL/SHY,FOSS,STY 3542 0.17 0.07 0.4 5.7 11.3 2.69 LM,SHY,FOSS,STY 3543 0.03 0.03 0.7 13.6 27.2 2.70 LM,SHY,FOSS,STY 3544 0.53 0.40 0.5 27.0 27.0 2.69 LM,SHY,FOSS,STY 3545 0.02 0.02 0.9 15.4 30.9 2.71 LM,SHY,FOSS,STY 3546 0.13 0.11 0.7 12.5 25.1 2.69 LM,SHY,FOSS,STY 3547 0.07 0.04 0.8 10.5 41.9 2.66 LM,SHY,SH-INCL,FOSS 3548 0.08 0.08 1.4 12.3 24.6 2.71 LM,SHY,FOSS 3549 0.20 0.11 1.0 18.4 18.4 2.68 LM,VF,SL/V,STY 3550 0.25 0.19 8.3 0.0 42.6 2.71 LM 3551 388.00 197.00 8.0 9.0 35.9 2.72 LM 3552 0.22 0.17 6.5 13.4 35.6 2.70 LM 3553 7.10 15.7 9.0 54.2 2.71 LM 3554 0.14 0.12 5.9 23.3 31.5 2.67 LM 3555 4.50 1.40 13.9 3.7 46.3 2.71 LM 3556 6.90 4.70 15.1 23.2 24.5 2.69 LM 3557 7.70 6.60 10.1 15.8 56.2 2.69 LM.V.FOSS 3558 3.50 1.10 8.9 3.6 48.7 2.71 LM 3559 0.16 0.13 4.7 0.0 71.2 2.69 LM 3560 0.77 5.4 0.0 67.9 2.71 LM,VF,V 3561 0.27 0.09 4.1 0.0 67.8 2.72 LM 3562 0.14 0.14 5.2 0.0 53.5 2.70 LM.PP 3563 0.43 0.34 9.3 0.0 65.6 2.71 LM.SH-INCL 3564 0.15 0.09 3.1 0.0 52.0 2.71 LOST CORE 3568 0.08 0.05 4.1 0.0 62.9 2.72 LM.VF 3569 0.12 0.07 3.5 11.2 44.8 2.72 LM,SL/V,FOSS,STY 3570 0.28 0.16 4.2 4.5 49.6 2.71 LM,SHY,VF,V 3571 4.30 2.90 9.6 9.6 38.4 2.70 LM,V,STY 3572 0.74 0.43 8.5 7.0 42.0 2.71 LM.STY 3573 0.55 0.52 6.6 15.8 15.8 2.70 LM.PP.FOSS 3574 0.05 0.03 2.7 10.8 48.5 2.72 LM 3575 3.00 1.50 6.0 5.0 40.3 2.70 LM,SL/F,SL/V,PP 3576 1.60 1.40 7.9 17.0 22.7 2.72 LM 3577 0.06 6.5 20.6 20.6 2.73 LM,SL/SHY/STY

185 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3578 6.00 0.98 5.3 5.8 40.9 2.71 LM 3579 0.01 3.2 0.0 62.0 2.71 LM 3580 0.01 3.1 0.0 62.0 2.73 LM.STY 3581 0.08 0.08 2.3 0.0 56.3 2.71 LM,SL/SHY,STY 3582 0.07 0.03 4.0 6.7 67.3 2.68 LM,SLA/,FOSS,STY 3583 0.11 0.09 5.0 3.3 56.4 2.71 LM 3584 7.40 0.30 5.3 4.5 66.8 2.69 LM 3585 0.30 0.29 7.6 3.7 60.0 2.68 LM,SLA/,FOSS 3586 0.44 0.40 9.2 3.5 55.4 2.71 LM 3587 0.12 0.10 3.1 9.7 53.3 2.71 LM,VF,SLA/,STY 3588 2.40 1.50 6.0 9.3 34.5 2.71 LOST IN TRANSIT 3590 2.70 0.44 4.7 0.0 53.4 2.71 LM,VF,STY 3591 0.08 0.07 2.2 0.0 53.2 2.72 LM,STY 3592 0.06 0.04 1.9 0.0 59.9 2.73 LM.PP.STY 3593 0.06 0.06 3.7 7.4 52.1 2.72 LM 3594 0.53 0.51 7.0 6.7 40.3 2.72 LM 3595 0.13 0.13 5.0 3.8 26.8 2.70 LM,VF,PP,STY 3596 0.05 0.05 2.5 7.5 44.9 2.72 LM.STY 3597 0.10 0.02 1.3 9.0 45.1 2.73 LM.STY 3598 0.05 0.05 2.1 9.5 47.5 2.73 LM,VF,SLA/,FOSS,STY 3599 0.12 0.07 2.1 7.5 45.0 2.72 LM.FOSS.STY 3600 0.01 0.01 2.2 5.6 50.5 2.73 LM,SL/ANHY,FOSS 3601 0.04 0.01 2.0 0.0 53.8 2.71 LM.PP 3602 0.10 0.07 2.8 0.0 59.2 2.71 LM,VF,SLA/ 3603 1085.00 59.00 3.4 0.0 67.9 2.64 LM 3604 0.24 0.24 5.1 3.9 59.1 2.73 LM 3605 0.06 0.06 6.2 4.5 49.8 2.73 LM,PP,FOSS,STY 3606 0.06 0.01 1.3 3.1 61.8 2.70 LM 3607 0.16 0.16 6.0 6.2 41.6 2.70 LM,SL/SHY,SLA/,STY 3608 3.70 0.44 4.2 4.7 47.2 2.70 LM,SLA/,FOSS,STY 3609 0.01 0.01 4.5 0.0 51.3 2.71 LM,VF,STY 3610 0.01 0.01 2.4 0.0 42.1 2.73 LM,VF,STY 3611 0.07 0.01 2.1 0.0 48.3 2.71 LM,VF,PP 3612 0.08 0.08 3.7 0.0 45.6 2.71 LM.PP.STY 3613 0.82 0.01 3.4 0.0 29.5 2.71 LM.STY 3614 0.01 0.01 1.2 0.0 55.3 2.70 LM,V,FOSS 3615 0.20 0.01 4.6 0.0 52.4 2.73 LM,V 3616 0.08 0.08 4.0 0.0 57.6 2.70 LM,SLA/,FOSS 3617 0.06 0.03 3.1 0.0 49.2 2.72 LM.SLA/ 3618 0.06 0.02 1.6 0.0 49.2 2.70 LM 3619 0.03 0.02 3.8 0.0 53.5 2.73 LM.SLA/ 3620 0.20 0.08 1.9 0.0 48.4 2.72 LM.STY 3621 1.40 0.60 2.5 0.0 50.7 2.73

186 Permit#35764 Ames, C W 1, Mt Pleasant Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3533 0.04 0.02 1.6 27.0 13.5 2.67 LM PP STY 3534 0.11 6.1 20.1 16.3 2.71 LM VF PP FOSS 3535 13 10.00 6.1 11.5 17.5 2.71 LM PP STY 3536 0.11 0.08 9 23.3 13.3 2.71 LM PP STY 3537 0.07 0.04 7.9 5.1 25.7 2.72 LM V STY 3538 0.17 0.08 7.2 43.2 31.7 2.72 LM V FOSS STY 3539 53 44.00 5.2 0.0 35.6 2.71 LM SLA/ FOSS STY 3540 0.08 0.05 3.5 0.0 41.7 2.71 LM SLA/ FOSS STY 3541 0.03 0.03 8.3 21.8 19.4 2.71 LM VF SLA/ FOSS STY 3542 0.17 0.07 4.5 9.3 55.7 2.71 LM VF SLA/ STY 3543 0.02 0.02 4.2 9.9 49.5 2.72 LM SLA/ STY 3544 0.19 0.07 2.9 0.0 65.8 2.71 LM V FOSS STY 3545 7.8 6.30 5.6 16.7 33.5 2.72 LM VF SL/V FOSS STY 3546 0.64 0.41 5.7 7.3 36.6 2.73 LM VF SL/V STY 3547 0.58 0.41 2.5 0.0 50.0 2.72 LM VF PP FOSS STY 3548 0.07 0.02 2.5 0.0 58.6 2.73 LM VF FOSS STY 3549 0.07 0.02 2.2 0.0 58.3 2.68 LM SLA/ FOSS STY 3550 0.84 0.79 2.6 0.0 66.2 2.71 LM VF SL/V FOSS STY 3551 1359 0.10 9.4 7.3 25.1 2.72 LM PP STY 3552 0.02 0.02 8.6 20.9 14.0 2.71 LM VF FOSS STY 3553 0.15 0.15 4 10.5 52.6 2.71 LM SL/SHY 3554 0.07 0.05 8.1 26.1 12.4 2.71 LM VF SLA/ FOSS STY 3555 0.32 0.32 2.4 0.0 43.1 2.70 LM SLA/ FOSS 3556 64 0.07 4.9 0.0 42.0 2.71 LMPP 3557 0.07 0.07 3.4 6.3 56.4 2.70 LM PP FOSS STY 3558 0.31 0.15 6.5 33.8 25.8 2.73 LM PP STY 3559 0.47 0.07 2.3 9.2 55.3 2.72 LM VF PP FOSS STY 3560 3.9 0.07 2.7 7.9 79.0 2.72 LM PP STY 3561 0.76 0.46 2.4 0.0 35.2 2.73 LM SL/V STY 3562 0.13 0.10 1.7 0.0 36.9 2.71 LM SLA/ STY 3563 0.26 0.04 3 0.0 62.4 2.72 LM PP STY 3564 0.58 0.08 1.5 0.0 57.2 2.70 LMSTY 3565 0.22 0.11 1.9 0.0 55.1 2.71 LM SL/F SLA/ 3566 0.22 0.15 3.2 0.0 65.4 2.72 LM PP STY 3567 0.14 0.14 2.4 0.0 43.5 2.71 LM PP FOSS 3568 0.04 0.01 3 0.0 42.0 2.71 LM FOSS STY

187 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3569 0.22 0.05 0.8 0.0 25.4 2.73 LMSTY 3570 0.01 0.01 1.8 0.0 24.1 2.70 LM FOSS 3571 0.01 0.01 1.9 0.0 43.9 2.71 LM FOSS STY 3572 0.14 0.07 2.1 10.1 50.5 2.72 LM V FOSS 3573 0.02 0.02 3 6.9 55.3 2.71 LM V STY 3574 1.8 0.07 3.4 0.0 61.3 2.72 LMSLA/ 3575 0.03 0.03 2.3 0.0 55.3 2.71 LM VF PP STY 3576 0.36 0.22 1.8 0.0 60.8 2.75 LM VF SLA/ 3577 0.22 0.01 1.4 0.0 61.8 2.71 LM VF SLA/ STY 3578 0.04 0.04 2.3 9.1 45.5 2.72 LM SLA/ STY 3579 0.04 0.02 3.1 6.9 48.5 2.69 LM VF SLA/ STY 3580 405 1.50 4.9 4.2 50.6 2.72 LM SL/F SLA/ STY 3581 2.1 1.80 2.8 15.3 53.6 2.70 LM V STY 3582 4.3 0.95 4 5.1 45.9 2.69 LMVFSLA/SH-INCL 3583 0.76 0.19 2 0.0 53.4 2.70 LM SLA/ STY 3584 0.01 0.01 2.9 7.2 50.7 2.71 LM PP STY 3585 0.01 0.01 4.1 0.0 35.6 2.72 LM VF PP FOSS STY 3586 0.04 0.02 2.3 0.0 55.0 2.71 LM VF SLA/ FOSS STY 3587 0.05 2 0.0 63.9 2.73 LM VF SL/V FOSS 3588 0.01 1.6 0.0 53.2 2.71 LMVSH-INCLSTY 3589 0.71 0.64 1.7 0.0 25.6 2.72 LM V STY 3590 0.28 0.07 1.3 0.0 32.1 2.71 LM VF S STY 3591 0.09 0.06 0.6 0.0 33.9 2.72 LM VF PP STY 3592 9.7 0.09 1.5 0.0 14.0 2.71 LM VF PP STY 3593 0.42 0.25 1.7 0.0 50.3 2.72 LM VF PP 3594 0.09 0.08 2.2 0.0 49.2 2.73 LM SL/F PP STY 3595 0.28 0.08 2.2 0.0 49.0 2.72

188 Permit#36227 Sokolowski, C T 1, Mt Pleasant Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3545 15.0 12.0 10.3 6.7 38.5 2.7 LM V FOSS STY 3546 983.0 983.0 7.7 5.3 42.1 2.7 LM V FOSS STY 3547 27.0 4.6 6.9 5.9 44.2 2.7 LMSLA/ 3548 18.0 16.0 6.5 6.3 53.7 2.7 LMV 3549 135.0 107.0 8.5 8.3 47.2 2.7 LM SLA/ STY 3550 7.0 2.2 7.6 5.4 54.0 2.7 LM V FOSS STY 3551 15.0 7.0 6.4 6.5 48.4 2.7 LM V FOSS STY 3552 1130.0 1130.0 6.8 10.5 42.1 2.7 LM VFV FOSS 3553 0.4 0.2 7.2 2.8 56.7 2.7 LM SLA/ PP 3554 5.6 0.9 8.2 17.3 29.7 2.7 LM PP STY 3555 0.2 0.0 7.3 5.5 22.1 2.7 LM VF PP FOSS 3556 0.5 0.2 8.2 2.5 49.1 2.7 LM V PP FOSS STY 3557 134.0 59.0 9.5 9.7 55.8 2.7 LM CALC V STY 3558 1.1 0.9 12.3 7.2 41.3 2.7 LM V FOSS STY 3559 1.7 1.4 13.2 5.2 41.6 2.7 LMV 3560 3.1 3.1 10.5 6.7 53.4 2.7 LMV 3561 0.8 0.6 6.4 3.2 54.0 2.7 LM VF V STY 3562 0.5 0.4 10.8 8.2 44.0 2.7 LM SLA/ PP FOSS STY 3563 23.0 4.2 10.4 8.6 47.9 2.7 LM CALC V 3564 41.0 5.9 9.3 4.3 54.1 2.7 LM V STY 3565 6.7 2.1 6.4 6.5 65.3 2.7 LM VF SLA/ STY 3566 0.1 0.1 5.3 13.9 55.4 2.7 LM SL/F PP FOSS STY 3567 0.1 0.1 8.1 5.0 40.2 2.7 LM SL/F STY 3568 0.1 0.0 7.6 5.4 54.0 2.7 LMSLA/ 3569 8.0 4.2 8.9 8.0 38.7 2.7 LM CALC V STY 3570 6.2 5.2 7.1 5.9 58.5 2.7 LM V STY 3571 905.0 349.0 7.4 9.7 44.4 2.7 LM CALC V STY 3572 1190.0 851.0 6.5 6.3 60.2 2.8 LM CALC V STY 3573 0.1 0.1 9.4 4.3 47.2 2.7 LM SL/F PP STY 3574 1739.0 1739.0 9.4 9.4 47.0 2.8 LM CALC V 3575 1127.0 563.0 8.8 4.6 39.3 2.7 LMV 3576 1.8 1.7 5.4 7.7 38.4 2.7 LM SLA/ FOSS STY 3577 0.2 0.1 8.1 5.0 53.0 2.7 LM SLA/ FOSS STY 3578 0.3 0.2 7.0 5.9 56.1 2.7 LMSTY 3579 0.1 0.1 6.5 6.4 57.4 2.7 LM PP FOSS STY 3580 4.2 0.6 8.5 4.8 52.6 2.7 LM PP STY

189 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3581 30.0 13.0 5.2 8.0 55.8 2.7 LM V FOSS STY 3582 31.0 29.0 8.9 4.6 48.1 2.7 LM F V FOSS STY 3583 6.3 4.1 6.9 6.0 57.1 2.7 LM V FOSS STY 3584 1.0 0.1 7.5 0.0 48.8 2.7 LM PP STY 3585 0.1 0.1 6.5 0.0 64.0 2.7 LM V FOSS 3587 0.0 0.0 7.7 5.4 56.6 2.7 LM PP FOSS 3588 0.0 0.0 8.6 0.0 60.5 2.7 LMPP 3589 4.5 1.1 4.3 0.0 43.9 2.7 LM SLA/ STY 3590 0.1 0.0 7.7 5.3 40.1 2.7 LM SLA/ STY *3591 0.1 6.2 0.0 60.9 2.7 LM CALC V 3592 99.0 2.8 7.1 5.9 59.5 2.7 LM CALC V STY 3593 0.1 0.0 5.1 0.0 49.6 2.7 LM PP STY 3594 0.3 0.2 7.7 5.4 56.7 2.7 LMSTY 3595 0.1 0.1 7.8 2.7 69.4 2.7 LM CALC V STY 3596 0.1 <0.01 6.8 3.1 74.2 2.7 LMSTY 3597 0.0 0.0 7.6 0.0 85.1 2.7 LMSTY 3598 0.1 0.1 5.5 0.0 60.8 2.7 LM VF PP FOSS STY 3599 0.1 0.1 5.3 0.0 53.0 2.7 LM CALC V FOSS STY 3600 0.2 0.1 4.8 0.0 47.2 2.7 LM V STY 3601 0.2 0.2 6.9 0.0 60.1 2.7 LM CALC V 3602 2006.0 2006.0 7.0 0.0 75.6 2.7 LM CALC V FOSS 3603 0.0 0.0 8.1 0.0 53.7 2.7 LM PP STY 3604 9.5 0.8 8.9 0.0 47.9 2.7 LM CALC V STY 3605 6.4 0.7 8.0 0.0 45.6 2.7 LM V STY *3606 163.0 7.8 0.0 40.0 2.7 LM CALC V 3607 25.0 17.0 8.1 0.0 63.3 2.7 LM V STY 3608 1.5 0.4 8.9 0.0 56.5 2.7 LM V STY

190 Permit#36259 Pfund-1, Mt Pleasant Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3526 0.44 0.06 0.8 19.8 49.6 2.70 LM.SL/SHY.FOSS.STY 3527 0.09 0.08 1.7 23.9 40.9 2.70 LM.SL/SHY.PP, 3528 0.04 0.02 1.4 16.8 42.1 2.69 LM.SL/SHY.STY 3529 0.04 0.02 1.8 16.8 50.4 2.69 LM.STY 3530 0.03 0.03 0.6 15.6 46.9 2.70 LM.SL/SHY.FOSS.STY 3531 0.52 0.26 0.5 49.0 16.3 2.70 LM.SL/SHY.FOSS.STY 3532 0.09 0.04 0.7 44.8 19.9 2.71 LM.SL/SHY.FOSS 3533 0.09 0.09 0.4 32.0 18.3 2.70 LM.SL/SHY.BREC, 3534 0.13 0.10 0.7 43.3 19.2 2.71 LM.SL/SHY.FOSS.STY 3535 0.12 0.04 0.6 32.8 18.7 2.67 LM.SL/SHY.FOSS.STY 3536 1.80 1.10 0.4 25.4 15.7 2.69 LM.SL/SHY.BREC 3537 0.62 0.44 0.7 56.5 12.5 2.68 LM.SLTY.SL/SHY.BRE 3538 0.07 0.07 0.8 19.1 21.8 2.67 LM.SL/SHY.BREC, 3539 0.08 0.07 4.3 7.0 16.0 2.69 LM.V.PP.FOSS 3540 0.16 0.14 2.4 11.2 50.2 2.71 LM.FOSS.STY 3541 1280 1020 13.2 25.6 7.1 2.74 LM.V.FOSS 3542 646 623 13.8 14.7 40.4 2.74 LM.V.FOSS 3543 4847 2999 12.9 0.0 6.3 2.74 LM.VF.V.FOSS *3544 10 9.0 13.1 75.1 2.71 LM *3545 166 13.1 6.9 57.1 2.71 LM 3546 1400 1019 12.5 10.4 55.3 2.74 LM.V.FOSS 3547 57 18 11.9 11.9 61.8 2.71 LM.V.FOSS 3548 13 0.28 6.4 13.5 60.1 2.72 LM.VF.V.FOSS 3549 254 178 10.1 5.5 54.9 2.71 LM.V.STY 3550 38 36.00 10.1 17.2 54.5 2.73 LM.V.FOSS 3551 1.60 0.12 5.4 0.0 53.9 2.72 LM.VF.SLA/.FOSS 3552 0.35 0.35 3.6 0.0 65.1 2.73 LM.VF.FOSS.STY 3553 0.29 0.12 4.2 4.6 68.0 2.70 LM.VF.PP.STY 3554 0.08 0.03 3.2 10.8 43.2 2.72 LM.VF.PP.STY 3555 28 19 11.6 15.7 40.4 2.70 LM.V.FOSS 3556 36 18 11.2 26.6 21.9 2.71 LM.V.FOSS.STY 3557 1.80 1.00 11.5 23.3 28.3 2.70 LM.VF.SL/V.PP 3558 1.10 0.36 8.7 13.9 35.8 2.69 LM.SL/SHY.VF.PP 3559 1.10 0.04 4.8 11.7 41.5 2.73 LM.VF.FOSS 3560 23.00 22.00 8.9 17.0 46.2 2.71 LM.V.FOSS *3561 0.30 5.2 8.7 56.5 2.73 LM 3562 3815 3.90 4.7 9.5 71.0 2.70 LM.VF.FOSS.STY 3565 40.00 20.00 12.1 5.2 36.1 2.72 LM.V.FOSS 3566 0.0 78.1 SAMPLE MISSING

191 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION *3567 0.01 3.2 21.8 40.9 2.71 LM 3568 6.7 67.4 SAMPLE MISSING 3569 0.12 0.09 2.6 18.9 37.8 2.70 LM.SL/SHY.PP.FOSS 3570 1.20 0.34 6.7 7.3 62.1 2.70 LM.PP.FOSS 3571 1.40 1.00 8.8 7.9 42.8 2.70 LM.SLA/.FOSS 3572 0.94 0.66 8.4 10.9 41.0 2.73 LM.SLA/.FOSS.STY 3573 126 0.38 7.2 11.6 62.7 2.70 LM.SL/V.FOSS.STY 3574 1198 1136 11.2 11.8 63.0 2.75 LM.VF.V 3575 344 232 10.8 5.3 72.0 2.73 LM.V.FOSS 3576 307 67 8.2 8.5 41.2 2.72 LM.V.FOSS.STY 3577 13 12 7.7 4.8 43.6 2.70 LM.V 3578 0.02 0.01 3.0 8.5 42.6 2.72 LM.VF.PP.FOSS 3579 0.05 0.05 4.4 0.0 67.3 2.72 LM.SL/V.FOSS.STY 3580 322 242 6.7 15.8 34.0 2.70 LM.V.STY 3581 4.10 2.00 6.3 0.0 57.6 2.73 LM.V.FOSS.STY 3582 0.70 0.62 5.6 0.0 56.3 2.70 LM.SLA/.FOSS.STY 3583 0.71 0.69 6.4 10.4 47.6 2.69 LM.PP.FOSS.STY 3584 0.67 0.37 8.0 11.3 35.3 2.69 LM.FOSS 3585 40.00 1.30 7.5 10.8 43.4 2.70 LM.VF.FOSS.STY 3586 0.84 0.42 5.5 10.1 46.2 2.69 LM.PP.FOSS.STY 3587 0.12 0.10 4.8 12.3 55.4 2.70 LM.PP 3588 2.60 0.96 4.7 4.7 46.7 2.71 LM.PP.STY 3589 1126 773 12.8 37.4 30.8 2.74 LM.VF.V 3590 1143 1126 13.3 12.9 31.7 2.74 LM.V.FOSS 3591 45 39 8.0 19.3 45.0 2.70 LM.VF.V.FOSS.STY 3592 3.60 3.00 6.2 14.2 50.4 2.68 LM.V.STY 3593 33.00 15.00 9.7 9.6 41.4 2.71 LM.SLA/.PP 3594 0.80 0.57 7.1 9.6 52.3 2.70 LM.VF.SLA/.PP.STY 3595 1.10 0.40 6.9 7.0 63.2 2.72 LM.SLA/.FOSS 3596 0.53 0.11 6.5 12.8 55.0 2.68 LM.VF 3597 14.00 0.19 4.7 13.3 64.7 2.69 LM.VF.PP 3598 0.90 0.69 5.0 18.0 59.2 2.71 LM.SLA/.FOSS.STY 3599 8.10 4.80 6.7 14.7 48.4 2.69 LM.PP.FOSS 3600 5.60 2.20 9.0 4.1 69.7 2.69 LM.VF.SLA/ 3601 0.53 0.43 7.1 0.0 73.4 2.71 LM.FOSS.STY 3602 0.33 0.29 5.1 2.7 57.2 2.69 LM.PP 3603 0.40 0.20 4.1 5.1 46.0 2.72 LM.VF.PP.STY 3604 28.00 1.20 4.3 5.2 44.2 2.72 LM.VF.STY 3605 8.30 7.00 4.8 2.9 63.3 2.69 LM.VF.PP 3606 2.00 0.44 8.4 0.0 67.6 2.72 LM.VF.PP.STY 3607 5201 0.32 8.0 0.0 69.0 2.72 LM.VF.PP 3608 0.61 0.27 7.5 0.0 53.5 2.71 LM.V.FOSS.STY

192 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3609 135 20.00 10.1 0.0 68.6 2.69 LM.VF.V 3610 7.20 0.86 8.1 0.0 67.9 2.72 LM.CALC.V 3611 3.40 0.94 7.9 2.8 74.8 2.71 LM.CALC.VF.V.STY 3612 0.46 0.46 8.2 2.8 70.5 2.69 LM,V,FOSS 3613 0.34 0.23 6.2 6.0 65.6 2.70 LM,VF,SL/V 3614 4.20 1.20 6.6 3.3 59.2 2.71 LM,VF,V,STY 3615 3.90 2.00 7.8 2.2 63.4 2.71 LM.VF.V 3616 5.70 2.50 8.4 0.0 65.7 2.70 LM,SL/V,FOSS,STY 3617 8.40 7.00 8.2 6.3 53.5 2.73 LM,SL/V,FOSS,STY 3618 1528 1528 8.8 2.8 59.4 2.73 LM,V,FOSS 3619 252 78 8.1 3.8 66.2 2.71 LM,CALC,FOSS,STY 3620 2177 1864 8.1 4.0 55.5 2.71 LM,V,FOSS 3621 23 15 10.3 2.5 66.0 2.77 LM,V 3622 1310 395 9.5 2.8 69.2 2.76 LM,V 3623 91 13 9.0 2.5 65.4 2.75 LM,V,STY *3624 0.06 5.5 3.1 58.0 2.73 LM,V,STY 3625 4.40 1.50 7.5 2.8 62.1 2.73 LM,V 3626 1.80 0.31 6.7 0.0 61.6 2.72 LM,SL/F,FOSS 3627 0.69 0.21 5.6 4.7 66.2 2.73 LM.PP.STY *3628 0.01 7.6 0.0 58.4 2.73 LM.PP.STY 3629 19.00 15.00 8.6 0.0 58.9 2.72 LM,V 3630 0.22 0.17 5.9 0.0 60.0 2.71 LM,V 3631 0.19 0.16 5.1 0.0 69.9 2.71 LM,V 3632 0.19 0.12 3.3 0.0 57.2 2.73 LM.STY *3633 0.01 3.6 0.0 56.7 2.75 LM.STY 3634 1.20 0.98 7.3 0.0 54.4 2.71 LM,SLA/,STY 3635 0.14 0.14 6.2 0.0 70.4 2.71 LM,SLA/,STY 3636 0.10 0.07 5.0 0.0 56.5 2.73 LM,PP,STY 3637 0.09 0.08 4.9 0.0 51.1 2.70 LM.PP 3639 0.01 0.01 3.1 0.0 64.6 2.75 LM,VF,PP,STY 3640 0.02 0.01 2.5 0.0 51.6 2.73 LM,SLA/,STY 3641 0.11 0.11 5.4 4.0 55.8 2.74 LM,SLA/,STY 3642 0.31 0.03 3.1 0.0 65.8 2.70 LM,SLA/,FOSS,STY 3643 0.26 0.24 3.5 0.0 48.9 2.74 LM.PP.STY 3644 73.00 2.30 9.3 0.0 61.2 2.72 LM.VF.SLA/ 3645 7.50 5.40 8.1 2.6 57.6 2.68 LM.V.FOSS 3646 0.06 0.06 5.6 0.0 55.1 2.73 LM,SL/F,PP 3647 0.01 0.01 2.9 0.0 60.5 2.73 LM 3648 0.12 0.01 3.0 0.0 61.6 2.72 LM.STY 3649 0.47 0.01 3.9 4.7 60.6 2.72 LM,VF,STY 3650 0.03 0.01 4.7 9.8 63.9 2.73 LM.PP.STY

193 Permit#36367 Mcclintic-3, Mt Pleasant Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3576 0.06 0.02 1.3 32.8 32.8 2.71 LM, FOSS 3577 0.04 0.04 1.3 34.1 34.1 2.71 LM, FOSS, STY 3578 0.02 0.02 1.1 20.4 40.7 2.71 LM, FOSS, STY 3579 0.04 0.04 4.0 74.8 10.7 2.71 LM, FOSS, STY 3580 0.16 0.12 2.3 54.7 18.2 2.68 LS, SL/SHY, FOSS 3581 0.03 0.01 2.6 64.5 16.1 2.68 LS, SL/SHY, SL/F, 3582 0.10 0.06 1.0 21.3 42.6 2.67 LS, SL/SHY, FOSS 3583 0.67 0.50 3.5 27.2 36.2 2.72 LM, SL/F, FOSS 3584 29.00 26.00 8.6 8.4 47.8 2.72 LM, VF, SLA/, STY 3585 7.00 0.05 7.3 25.2 36.4 2.68 LM, VF, SLA/ 3586 0.03 0.01 2.8 0.0 68.6 2.67 LM, PP, STY 3587 0.01 0.01 2.4 0.0 78.6 2.68 LM, SL/F, SLA/, 3588 19.00 11.00 9.7 14.6 45.8 2.72 LM, V 3589 3.00 1.30 6.9 24.1 57.3 2.68 LM, V, FOSS 3590 1.20 9.1 17.9 47.1 2.70 LM, VF, V, FOSS 3591 435 328. 11.0 14.3 39.4 2.69 LM, V, STY 3592 4.30 4.10 2.2 9.5 56.9 2.71 LM, VF, SLA/, STY 3593 11.00 7.60 8.7 20.9 41.7 2.70 LM, V 3594 0.38 0.10 8.5 19.2 40.8 2.71 LM, V, STY 3595 29.00 27.00 8.3 17.1 41.6 2.70 LM, V, STY 3596 2.30 2.10 4.9 37.9 29.5 2.70 LM, VF, SLA/ 3597 0.01 0.01 4.3 51.4 24.5 2.70 LM, VF, SLA/ 3598 0.01 0.01 7.4 29.1 13.9 2.69 LM, SLA/ 3599 2.60 0.18 2.1 0.0 50.0 2.72 LM, SL/F, V, STY 3600 0.17 0.14 7.4 19.5 22.3 2.70 LM, V, STY 3601 192 171. 10.7 14.8 33.4 2.69 LM, VF, V 3602 27 7.3 19.4 25.0 2.68 LM, VF, V 3604 LOST CORE 3605 0.15 0.13 7.6 18.6 23.9 2.69 LM, V 3606 0.08 0.03 7.3 22.6 33.9 2.70 LM, V, STY 3607 0.04 0.04 1.6 0.0 66.7 2.68 LM, VF, SL/V, STY 3608 0.14 0.12 2.1 10.3 72.1 2.72 LM, VF, V, STY 3609 1.90 5.2 32.0 28.0 2.69 LM, VF, V, PP, 3610 0.02 4.9 25.4 21.1 2.71 LM, VF, V, STY 3611 0.08 0.05 1.5 14.7 58.7 2.70 LM, STY 3612 0.02 0.02 2.3 18.4 64.5 2.70 LM, VF, STY

194 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3613 0.25 0.25 2.2 9.8 68.8 2.70 LM, VF, PP 3614 0.19 0.14 4.0 23.6 42.0 2.68 LM, VF, FOSS, 3615 0.16 0.14 3.8 5.5 60.7 2.72 LM, VF, FOSS, 3616 0.19 0.15 4.1 0.0 62.3 2.72 LM, VF, FOSS, 3617 0.03 0.01 3.2 0.0 72.3 2.72 LM 3618 0.02 0.02 4.7 15.6 62.4 2.73 LM STY 3619 0.18 0.07 3.7 25.5 45.3 2.71 LM VF, V, STY 3620 0.01 0.01 3.6 5.9 71.3 2.71 LM SLA/ 3621 0.02 0.01 4.5 9.4 56.5 2.71 LM V, FOSS 3622 0.03 0.03 3.9 5.5 77.0 2.72 LM PP, FOSS 3623 0.01 0.01 3.6 35.9 41.8 2.72 LM STY 3624 0.03 0.01 2.0 10.8 53.9 2.71 LM VF, SLA/, PP, 3625 0.21 0.04 3.5 21.3 42.6 2.71 LM SLA/, FOSS 3626 0.05 0.03 2.4 9.0 54.3 2.71 LM PP, FOSS, STY 3627 37.00 0.04 2.8 7.5 60.0 2.72 LM VF, PP, FOSS, 3628 0.01 2.2 0.0 47.1 2.71 LM SL/ANHY, STY 3629 0.13 0.07 2.2 0.0 57.2 2.72 LM PP, FOSS, STY 3630 0.01 0.01 1.7 12.6 50.4 2.73 LM PP, STY 3631 3.60 2.70 1.7 0.0 61.4 2.73 LM VF, PP, FOSS, 3632 0.31 0.12 3.6 6.0 65.6 2.73 LM VF, SLA/ 3633 0.12 0.04 4.1 10.3 20.7 2.72 LM VF, STY 3634 0.80 0.69 1.9 0.0 45.9 2.72 LM VF, STY 3635 0.01 0.01 3.4 0.0 31.3 2.72 LM VF, STY 3636 0.01 1.7 0.0 62.4 2.73 LM VF, STY 3637 0.01 1.7 0.0 63.0 2.73 LM VF, STY 3638 0.25 0.04 2.4 8.7 69.6 2.73 LM SLA/ 3639 0.02 0.02 2.8 0.0 60.1 2.72 LM SLA/, FOSS 3640 2.50 2.00 2.7 0.0 64.1 2.72 LM SLA/, FOSS, 3641 17.00 0.01 3.0 7.0 69.7 2.75 LM VF, SL/V, STY 3642 0.01 5.5 7.5 29.9 2.72 LM VF, STY 3643 0.02 2.6 8.1 48.7 2.71 LM VF, SLA/, STY 3644 0.01 2.2 0.0 39.6 2.73 LM VF, STY 3645 0.01 1.0 0.0 43.1 2.75 LM VF, PP, STY 3646 0.01 0.01 1.5 0.0 56.6 2.69 LM, PP 3647 0.04 0.01 2.2 0.0 38.8 2.71 LM, VF, STY 3648 0.04 0.02 3.7 0.0 40.0 2.73 LM, STY 3649 0.05 0.05 2.1 9.9 49.7 2.72 LM, PP, STY 3650 0.01 3.3 0.0 70.7 2.72 LM, VF, PP, STY

195 Permit#36387 Miller, Viola 1, Mt Pleasant Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3561 0.01 0.01 1.8 41.8 23.9 2.71 LS.F/XL.GY 3562 0.03 0.03 2.9 44.1 14.7 2.70 LS.F/XL.GY 3563 0.01 0.01 1.7 25.3 25.3 2.72 LS,F/XL,GY 3564 0.01 0.01 1.5 28.7 28.7 2.71 LS,F/XL,GY 3565 0.01 0.01 3.1 30.9 34.3 2.69 LS.F-M/XL.GY 3566 0.02 0.02 2.5 17.0 42.6 2.72 LS,F-M/XL,GY 3567 0.02 0.02 2.1 20.7 51.8 2.71 LS F-M/XL.GY 3568 0.02 0.01 1.9 23.0 45.9 2.72 LS F-M/XL.GY 3569 0.03 0.02 1.4 31.0 31.0 2.71 LS F-M/XL.GY 3570 0.03 0.03 3.2 13.4 40.1 2.71 LS F-M/XL.GY 3571 0.01 0.01 1.6 26.1 26.1 2.71 LS F-M/XL.GY 3572 0.02 0.02 1.3 16.6 33.2 2.71 LS F-M/XL.GY 3573 0.03 0.01 1.4 31.1 15.5 2.71 LS F-M/XL.GY 3574 0.03 0.03 1.7 12.6 50.3 2.70 LS F-M/XL.GY 3575 0.01 0.01 1.4 30.7 30.7 2.71 LS F-M/XL.GY 3576 0.36 0.04 2.6 37.6 33.4 2.72 LS F/XL.GY 3577 0.03 0.02 2.4 17.6 44.1 2.70 LS F/XL.GY 3578 0.03 0.03 2.0 10.4 52.2 2.71 LS F/XL.P-P/POR.GY 3579 0.04 0.03 1.2 18.3 36.3 2.71 LS F/XL.BUFF 3580 0.01 0.01 1.0 20.8 41.6 2.70 LS F/XL,BUFF 3581 0.20 0.17 1.2 17.9 35.9 2.70 LS F/XL.GY 3582 0.06 0.06 1.4 15.1 15.1 2.70 LS F/XL.GY 3583 0.02 0.02 1.3 17.1 34.1 2.70 LS F-M/XL.GY 3584 0.08 0.08 1.3 16.0 32.0 2.70 LS F-M/XL.GY 3585 0.05 0.04 1.5 28.8 28.8 2.70 LS F-M/XL.GY 3586 0.05 0.05 1.9 38.4 22.0 2.70 LS F-M/XL.GY 3587 0.04 0.02 1.8 41.8 12.0 2.71 LS F-M/XL.GY 3588 0.07 0.06 1.8 40.8 23.3 2.70 LS F-M/XL.GY 3589 0.05 0.03 4.7 8.9 39.9 2.71 LS F-M/XL.GY 3590 0.14 0.10 3.2 6.6 39.7 2.71 LS F/XL,P/POR,BUFF 3591 0.72 0.18 2.1 10.0 59.8 2.71 LS F/XL, P/POR.BUFF 3592 0.07 0.05 1.6 13.0 52.1 2.71 LS F/XL, P/POR,BUFF 3593 0.09 0.04 2.5 8.6 69.0 2.73 LS F/XL.BUFF 3594 0.03 0.01 2.6 0.0 49.8 2.70 LS, F/XL.BUFF 3595 0.01 0.00 2.8 7.7 53.6 2.71 LS, F/XL.P/POR.BUFF 3596 0.20 0.10 5.0 14.7 33.6 2.72 LS, F/XL, P/POR,BUFF

196 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3597 0.06 6.8 0.0 36.7 2.70 LS,F/XL,P/POR,BUFF 3598 0.03 0.03 4.3 4.9 34.0 2.70 LS,F/XL,BUFF 3599 0.26 0.04 2.7 15.8 63.3 2.71 LS,F/XL,P/POR,BUFF 3600 0.04 0.01 1.9 0.0 57.2 2.71 LS,F/XL,BUFF 3601 15.00 7.5 12.1 21.5 2.70 LS,F/XL,BUFF 3602 0.06 0.01 3.9 10.8 43.3 2.71 LS,F/XL,P/POR,BUFF 3603 275.00 0.01 1.9 0.0 68.8 2.71 LS,F/XL,P/POR,BUFF 3604 0.01 0.01 2.3 0.0 74.7 2.72 LS,F/XL,BUFF 3605 0.01 1.5 0.0 55.2 2.70 LS,F/XL,BUFF 3606 0.23 0.01 2.5 0.0 33.2 2.70 LS,F/XL,P/POR,BUFF 3606 Core Lost 3615 0.08 0.04 2.7 15.8 47.4 2.74 LS.F/XL, P/POR.BUFF 3616 0.16 0.16 0.9 0.0 47.7 2.71 LS,F/XL,BUFF 3617 0.07 0.05 0.9 0.0 45.6 2.72 LS,F/XL,BUFF 3618 0.23 0.01 1.3 16.5 33.1 2.72 LS.F-M/XL.BUFF 3619 0.07 0.06 1.3 0.0 32.8 2.72 LS,F/XL,BUFF 3620 26.00 0.68 1.1 0.0 38.2 2.72 LS.F/XL.BUFF 3621 0.42 0.40 1.6 0.0 53.1 2.71 LS,F/XL,BUFF 3622 0.04 0.03 3.2 13.4 26.8 2.74 LS.F/XL.BUFF 3623 0.07 0.05 3.1 7.0 48.8 2.73 LS,F/XL,BUFF 3624 2.5 0.0 42.7 2.72 LS,F/XL,BUFF 3625 1.5 13.9 55.6 2.71 LS,F/XL,BUFF 3626 0.01 2.3 18.7 46.7 2.71 LS,F/XL,BUFF 3627 0.05 0.04 0.7 0.0 29.9 2.71 LS,F/XL,BUFF 3628 1.20 0.20 1.4 30.8 30.8 2.72 LS,F/XL,BUFF 3629 0.09 0.03 2.0 10.7 53.6 2.72 LS,F/XL,BUFF 3630 0.02 0.02 2.5 8.8 61.3 2.73 LS,F/XL,BUFF 3631 0.02 0.02 1.5 0.0 56.6 2.72 LS,F/XL,BUFF 3632 0.15 0.10 3.7 5.8 58.1 2.75 LS,F/XL,BUFF 3633 0.04 0.04 2.9 12.3 49.5 2.74 LS.F/XL.BUFF 3634 0.03 0.03 2.6 8.1 40.3 2.71 LS,F/XL,BUFF 3635 0.15 0.15 4.4 21.4 33.2 2.74 LS,F/XL,BUFF 3636 0.05 0.05 1.9 0.0 45.1 2.72 LS,F/XL,BUFF 3637 0.23 0.13 4.1 10.2 20.3 2.72 LS,F/XL,BUFF 3638 0.17 0.05 2.5 0.0 42.1 2.72 LS,F/XL,BUFF 3639 1.20 0.72 7.6 28.4 21.7 2.74 LS,F/XL,GY 3640 0.24 0.13 1.7 12.4 49.6 2.72 LS,F/XL,BUFF 3641 0.16 0.12 3.2 13.4 40.3 2.72 LS,F/XL,BUFF 3642 1.70 0.23 3.3 12.9 57.9 2.72 LS,F/XL,BUFF

197 Permit#39770 Mt Pleasant Unit Tract 55 Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3561 0.2 0.1 1.0 0.0 28.3 2.71 LS,F/XL,GY 3562 0.1 0.1 0.6 0.0 19.3 2.70 LS,F/XL,GY 3563 0.1 0.1 0.3 0.0 34.2 2.70 LS.F/XL.GY 3564 0.1 0.1 0.4 0.0 26.9 2.70 LS,F/XL,GY 3565 0.1 0.1 0.5 0.0 33.7 2.70 LS,F/XL,GY 3566 0.1 0.1 0.5 0.0 29.8 2.69 LS,F/XL,GY 3567 0.1 0.1 0.3 0.0 24.6 2.69 LS,F/XL,GY 3568 0.5 0.4 0.2 0.0 40.7 2.69 LS,F/XL,GY 3569 0.8 0.3 0.3 0.0 43.0 2.69 LS,F/XL,GY 3570 0.1 0.1 0.3 0.0 28.5 2.69 LS,F/XL,GY 3571 0.2 0.1 0.3 0.0 52.4 2.69 LS,F/XL,GY 3572 0.1 0.1 0.2 0.0 43.0 2.69 LS,F/XL,GY 3573 0.1 0.1 0.3 0.0 47.0 2.69 LS.F/XL.GY 3574 1.4 1.2 0.3 0.0 45.5 2.65 LS.F/XL.GY 3575 0.1 0.1 0.3 0.0 55.0 2.69 LS.F/XL.GY 3576 9.1 6.2 6.7 18.6 26.9 2.71 LS,F/XL,GY,VUG 3577 231.0 227.0 9.6 17.3 26.0 2.71 LS,F/XL,GY,VUG 3578 45.0 23.0 5.5 16.8 19.2 2.69 LS,F/XL,GY,VUG 3579 0.6 0.3 1.9 23.1 16.5 2.69 LS,F/XL,GY,STY 3580 0.1 0.1 2.7 0.0 61.8 2.71 LS,F/XL,GY 3581 3.2 1.4 2.8 0.0 12.2 2.70 LS,F/XL,VUG,V/F 3582 6.6 4.0 7.2 21.8 19.4 2.71 LS,F/XL,GY,VUG 3583 10.0 4.3 6.9 13.8 24.5 2.71 LS,F/XL,GY,VUG 3584 25.0 21.0 10.1 13.6 24.8 2.70 LS,F/XL,GY,VUG 3585 0.1 0.1 6.3 14.1 25.9 2.70 LS,F/XL,GY,VUG 3586 18.0 14.0 9.9 13.8 20.8 2.71 LS,F/XL,GY,VUG 3587 44.0 40.0 9.1 0.0 71.5 2.71 LS,F/XL,GY,VUG 3588 75.0 59.0 11.5 0.0 33.6 2.71 LS,F/XL,GY,VUG 3589 528.0 510.0 11.7 11.0 39.3 2.71 LS,F/XL,GY,VUG 3590 992.0 454.0 11.9 13.9 39.8 2.70 LS,F/XL,GY,VUG 3591 337.0 293.0 9.1 13.9 30.1 2.71 LS,F/XL,GY,VUG 3592 0.0 2.7 33.7 19.6 2.70 LS.F/XL.GY 3593 0.1 0.1 0.4 0.0 72.2 2.67 LS.F/XL.GY 3594 1.2 1.2 6.4 29.6 50.8 2.70 LS,F/XL,GY,VUG 3595 17.0 14.0 13.9 10.0 24.5 2.82 LS,F/XL,GY,VUG 3596 17.0 13.0 8.3 17.0 30.3 2.70 LS,F/XL,GY,VUG

198 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3597 0.1 0.1 4.2 0.0 73.1 2.70 LS,F/XL,GY,STY 3598 0.1 0.1 1.8 52.0 14.8 2.69 LS,F/XL,GY,STY 3599 28.0 5.8 7.1 0.0 18.5 2.71 LS,F/XL,GY,VUG 3600 0.1 0.1 2.7 0.0 26.4 2.69 LS,F/XL,GY,STY 3601 0.1 0.1 1.0 0.0 66.4 2.68 LS,F/XL,GY 3602 0.1 0.1 0.8 0.0 61.1 2.67 LS,F/XL,GY 3603 0.1 0.1 0.8 0.0 71.9 2.70 LS,F/XL,GY,STY 3604 14.0 5.4 6.8 0.0 25.3 2.70 LS,F/XL,GY,VUG 3605 20.0 19.0 7.7 11.1 19.0 2.70 LS,F/XL,GY,VU 3606 0.2 0.1 4.7 33.3 14.8 2.69 LS,F/XL,GY,VUG 3607 0.3 0.2 1.3 0.0 51.4 2.68 LS,F/XL,GY,STY 3608 0.2 0.2 1.7 0.0 57.0 2.67 LS,F/XL,GY,STY 3609 51.0 16.0 1.7 0.0 52.6 2.68 LS,F/XL,GY,STY 3610 0.4 0.2 2.1 0.0 48.7 2.68 LS,F/XL,GY,STY 3611 0.2 0.2 1.0 0.0 32.5 2.67 LS,F/XL,GY,STY 3612 0.1 0.1 3.4 11.6 34.7 2.68 LS,F/XL,GY,VUG 3613 12.0 9.6 5.7 13.6 23.3 2.71 LS,F/XL,GY,VUG 3614 1.8 1.7 2.6 13.1 18.7 2.70 LS,F/XL,GY,VUG 3615 0.1 0.1 1.0 9.3 65.4 2.68 LS,F/XL,GY,STY 3616 0.1 0.1 0.5 13.1 45.8 2.68 LS,F/XL,GY 3617 0.1 0.1 2.1 16.6 47.4 2.66 LS,F/XL,GY,STY 3618 20.0 5.4 5.7 12.8 38.4 2.69 LS,F/XL,GY,STY 3619 0.1 0.1 0.7 17.0 50.9 2.66 LS,F/XL,GY 3620 0.1 0.1 3.4 16.1 32.3 2.70 LS,F/XL,GY,VUG

199 Permit#39771 Mt Pleasant Unit Tract 46, Mt Pleasant Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3576 1.6 26.3 26.3 2.71 LS,F/XL,BLK 3577 1.5 0.5 14.7 2.71 LS,F/XL,BLK 3578 1.8 0.0 23.3 2.71 LS,F/XL,BLK 3579 1.4 0.0 15.0 2.68 LS,F/XL,BLK 3580 2.6 0.0 18.3 2.72 LS,F/XL,BLK 3581 2.2 0.0 19.8 2.71 LS,F/XL,BLK 3582 1.3 0.0 16.5 2.70 LS,F/XL,BLK 3583 1.5 0.0 14.2 2.72 LS,F/XL,BLK 3584 1.4 0.0 14.9 2.70 LS,F/XL,BLK 3585 1.3 0.0 16.3 2.72 LS,F/XL,BLK 3586 1.7 0.0 12.7 2.72 LS,F/XL,BLK 3587 1.7 0.0 12.4 2.71 LS,F/XL,BLK 3588 1.7 0.0 12.8 2.72 LS,F/XL,BLK 3589 2.1 0.0 10.1 2.71 LS,F/XL,BLK 3590 2.1 0.1 10.3 2.72 LS,F/XL,BLK 3591 4.8 19.8 26.4 2.72 LS,F/XL,GY,STY 3592 6.9 13.3 14.8 2.71 LS,F/XL,GY,STY,VUG 3593 5.4 18.3 32.5 2.71 LS,F/XL,GY 3594 11.2 33.3 10.5 2.70 LS,F/XL,GY,SLA/UG 3595 4.6 47.1 9.0 2.69 LS,F/XL,GY 3596 5.0 25.1 25.1 2.74 LS,F/XL,GY 3597 2.8 26.8 38.3 2.71 LS,F/XL,GY 3598 4.2 17.2 24.6 2.70 LS,F/XL,GY,SL/VUG 3599 8.2 17.4 32.2 2.72 LS,F/XL,GY,VUG 3600 7.7 11.9 34.4 2.71 LS,F/XL,GY,VUG 3601 7.1 12.9 37.2 2.71 LS,F/XL,GY,VUG 3602 15.4 25.7 20.8 2.71 LS,F/XL,GY,VUG 3603 9.3 17.2 28.0 2.72 LS,F/XL,GY,VUG 3604 4.4 9.5 28.5 2.72 LS,F/XL,GY,SLA/UG 3605 3.3 13.0 39.1 2.73 LS,F/XL,GY,SLA/UG 3606 7.0 20.4 17.5 2.73 LS,F/XL,GY,VUG 3607 6.0 23.7 13.5 2.69 LS,F/XL,GY,STY 3608 2.5 49.8 18.3 2.69 LS.F/XL.GY 3609 9.0 44.5 14.5 2.72 LS,F/XL,GY,STY 3610 8.3 45.8 12.4 2.71 LS.F/XL.GY 3611 6.8 53.4 13.0 2.68 LS,F/XL,GY,SLA/UG 3612 6.7 27.7 21.5 2.73 LS,F/XL,GY,STY,VUG 3613 8.0 17.7 20.2 2.71 LS,F/XL,GY,VUG 3614 3.2 23.1 39.5 2.71 LS,F/XL,GY,SL/VUG

200 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3615 2.7 7.8 39.1 2.70 LS,F/XL,GY,STY 3616 2.5 37.6 16.7 2.72 LS,F/XL,GY,VUG 3617 6.3 19.3 12.9 2.70 LS,F/XL,GY,STY 3618 0.3 2.5 12.6 2.69 LS,F/XL,GY,STY 3619 2.1 0.0 20.0 2.71 LS,F/XL,GY,STY 3620 3.5 26.9 23.9 2.70 LS,F/XL,GY 3621 4.5 16.3 18.6 2.71 LS,F/XL,GY,VUG 3622 3.7 11.2 11.2 2.69 LS,F/XL,GY,STY 3623 4.0 30.8 20.5 2.69 LS,F/XL,GY,STY 3624 3.1 41.1 13.7 2.73 LS,F/XL,GY 3625 4.1 54.3 25.8 2.72 LS,F/XL,GY,SL/VUG 3626 2.8 25.9 14.8 2.70 LS.F/XL.GY 3627 2.3 9.2 18.3 2.72 LS.F/XL.GY 3628 2.4 8.9 35.5 2.72 LS,F/XL,GY 3629 1.9 11.2 11.2 2.70 LS,F/XL,GY,SLA/UG 3630 1.4 14.9 14.9 2.70 LS,F/XL,GY,SLA/UG 3631 0.3 9.8 29.4 2.71 LS,F/XL,GY,SLA/UG 3632 3.8 11.1 39.0 2.71 LS,F/XL,GY,SLA/UG 3633 2.7 15.6 31.2 2.69 LS,F/XL,GY,SLA/UG 3634 4.1 10.3 25.7 2.71 LS,F/XL,GY,STY 3635 5.1 18.2 24.3 2.71 LS,F/XL,GY,STY,VUG 3636 2.8 7.5 30.0 2.72 LS,F/XL,GY,STY

201 Permit # 36366 Wheeler, Roland Mt Pleasant Field Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3571 0.16 0.09 2.1 44.8 19.9 2.70 LS,F/XL,BLK 3572 0.06 0.04 2.4 8.9 44.6 2.70 LS,F/XL,BLK 3573 0.07 0.06 3.1 23.9 41.0 2.72 LS,F/XL,BLK 3574 0.06 0.06 2.6 29.1 41.5 2.72 LS,F/XL,BLK 3575 0.06 0.05 3.1 30.7 40.9 2.71 LS,F/XL,BLK 3576 0.08 0.08 1.9 22.2 22.2 2.72 LS.F/XL.BLK 3577 0.14 0.11 1.5 28.8 14.4 2.72 LS,F/XL,BLK 3578 0.08 0.05 0.9 23.1 23.1 2.71 LS,F/XL,BLK 3579 0.20 0.14 1.6 48.2 13.8 2.73 LS,F/XL,BLK 3580 0.63 0.43 1.8 23.9 12.0 2.74 LS,F/XL,BLK 3581 0.20 0.06 2.4 18.1 36.2 2.74 LS,F/XL,BLK 3582 0.20 0.14 3.0 25.0 28.5 2.78 LS,F/XL,BLK 3583 0.32 0.27 2.2 34.7 9.9 2.73 LS,F/XL,BLK 3584 0.41 0.30 1.3 32.8 16.4 2.71 LS,F/XL,BLK 3585 0.07 0.07 2.9 51.7 7.4 2.74 LS,F/XL,BLK 3586 0.07 0.04 1.8 41.8 12.0 2.72 LS,F/XL,BLK 3587 0.08 0.07 1.2 18.0 18.0 2.72 LS.F/XL.BLK 3588 0.47 0.23 1.0 20.6 20.6 2.72 LS,F/XL,BLK 3589 0.12 0.09 2.9 7.4 59.2 2.74 LS.F/XL.BLK 3590 0.12 0.12 4.1 0.0 45.9 2.72 LS,F/XL,BUFF 3591 1.20 0.54 2.9 0.0 59.5 2.73 LS,F/XL,BUFF 3592 0.33 0.15 3.5 12.1 24.2 2.73 LS,F/XL,P/POR,BUFF 3593 0.01 0.01 2.9 7.3 51.2 2.72 LS,F/XL,BUFF 3594 0.07 0.07 3.8 19.5 27.9 2.73 LS,F/XL,SL/VUG,BUFF 3595 0.55 0.44 4.5 28.2 18.8 2.73 LS,F/XL,P/POR,BUFF 3596 0.09 0.07 3.4 0.0 49.2 2.72 LS,F/XL,BUFF 3597 0.09 0.05 3.2 13.2 46.1 2.74 LS,F/XL,BLK 3598 0.26 0.15 6.2 15.0 16.6 2.74 LS,F/XL,P-P/POR,BLK 3599 0.21 0.18 3.1 13.7 13.7 2.75 LS,F/XL,BLK 3600 0.20 0.20 5.6 16.9 26.2 2.74 LS,F/XL,P-P/POR,BLK 3601 0.05 0.03 4.3 22.0 34.3 2.73 LS,F/XL,P-P/POR,BLK 3602 2.00 0.33 3.8 11.3 45.1 2.74 LS,F/XL,P-P/POR,BLK 3603 7.00 6.40 3.0 7.1 49.4 2.73 LS.F/XL.BUFF 3604 0.17 0.17 2.4 0.0 44.8 2.73 LS.F/XL.BUFF 3605 1.00 0.46 2.9 14.5 36.2 2.72 LS.F/XL.BLK 3606 0.01 5.5 22.5 26.2 2.72 LS,F/XL,P-P/POR,BLK 3607 0.46 0.43 2.2 9.6 38.2 2.72 LS,F/XL,P-P/POR,BLK 3608 8.90 6.50 4.2 22.8 20.3 2.74 LS,F/XL,P-P/POR,BLK 3609 1.10 0.72 5.0 14.7 33.6 2.75 LS.F/XL.BUFF

202 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3610 1.30 1.00 3.3 12.8 44.8 2.73 LS,F/XL,BLK 3611 0.01 2.7 7.9 55.2 2.72 LS,F/XL,BUFF 3612 0.01 2.6 8.1 40.5 2.71 LS,F/XL,BUFF 3613 0.10 0.09 3.8 19.5 33.4 2.75 LS,F/XL,P-P/POR 3614 0.01 3.3 12.9 45.1 2.73 LS,F/XL,BLK 3615 0.20 0.17 2.9 0.0 59.0 2.70 LS.F/XL.BUFF 3616 0.16 0.14 3.0 0.0 56.4 2.73 LS,F/XL,BUFF 3617 0.10 0.04 5.7 7.4 40.9 2.75 LS,F/XL,BUFF 3618 0.16 0.12 5.9 7.2 43.0 2.77 LS,F/XL,GY 3619 0.01 2.5 8.6 51.7 2.72 LS.F/XL.GY 3620 2.60 0.26 2.1 10.4 20.7 2.74 LS,F/XL,GY/BLK 3621 0.32 0.14 4.2 22.8 50.8 2.73 LS,F/XL,GY/BLK 3622 0.08 0.02 7.3 5.6 22.3 2.74 LS,F/XL,P-P/POR,GY 3623 0.01 5.2 0.0 16.2 2.78 LS,F/XL,GY 3624 0.98 0.01 2.9 7.5 67.3 2.74 LS,F/XL,BUFF 3625 0.54 0.41 2.7 0.0 54.2 2.71 LS,F/XL,BUFF 3626 1.40 1.20 2.7 16.2 40.6 2.75 LS,F/XL,BLK 3627 0.06 0.02 0.9 0.0 46.2 2.72 LS,F/XL,BLK 3628 0.73 0.01 4.4 1.9 68.6 2.76 LS,F/XL,GY/BLK 3629 3029.00 2.20 2.2 0.0 69.4 2.74 LS,F/XL,GY/BLK 3630 0.42 0.42 2.7 0.0 31.1 2.73 LS,F/XL,GY/BLK 3631 0.12 0.07 3.3 0.0 70.9 2.73 LS,F/XL,GY/BLK 3632 0.11 0.09 3.3 0.0 64.2 2.72 LS,F/XL,GY/BLK 3633 0.17 0.15 4.0 0.0 58.9 2.73 LS,F/XL,BUFF/GY 3634 0.10 0.10 3.4 0.0 44.1 2.73 LS,F/XL,BUFF/GY 3635 0.04 0.04 1.5 0.0 8.0 2.72 LS,F/XL,BLK 3636 0.04 0.01 3.4 0.0 56.2 2.73 LS,F/XL,GY/BLK 3637 0.07 0.07 3.7 11.4 51.1 2.73 LS,F/XL,GY/BLK 3638 147.00 116.00 6.3 6.6 26.5 2.74 LS,F/XL,FOSS,GY 3639 0.16 0.07 2.2 9.9 39.5 2.72 LS,F/XL,GY/BLK 3640 0.29 0.25 1.8 0.0 47.3 2.71 LS,F/XL,GY/BLK 3641 0.03 0.03 1.8 11.6 23.3 2.73 LS,F/XL,GY/BLK 3642 0.04 0.03 1.1 20.5 20.5 2.71 LS,F/XL,GY/BLK 3643 0.04 0.04 1.9 22.2 22.2 2.74 LS,F/XL,GY/BLK 3644 0.10 0.07 2.2 9.7 19.5 2.74 LS,F/XL,GY/BLK

203 Permit # 36258 Van Gaever & Lockwood Mt Pleasant Field Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3530 12.00 11.00 9.1 9.9 46.3 2.72 LM V FOSS 3531 502.00 442.00 7.8 11.8 52.4 2.73 LM V FOSS STY 3532 0.28 0.12 4.6 4.5 72.5 2.73 LM V FOSS STY 3533 0.07 0.07 6.2 15.0 43.3 2.72 LM VF FOSS STY 3534 170.00 143.00 8.5 25.4 43.6 2.72 LM V FOSS STY 3535 0.27 0.27 7.0 10.5 59.7 2.72 LM V STY 3536 0.09 0.09 8.5 4.8 45.3 2.72 LM SLA/ STY 3537 33.00 5.50 9.1 10.0 42.1 2.72 LM V FOSS 3538 2.30 1.50 7.2 20.0 45.8 2.72 LM V FOSS STY 3539 0.06 0.06 3.3 0.0 69.6 2.72 LM FOSS 3540 0.13 0.10 3.1 0.0 53.6 2.72 LMSTY 3541 0.08 0.06 3.3 6.3 50.6 2.75 LM PP STY 3542 2.80 1.60 7.1 2.9 63.6 2.73 LM V FOSS STY 3543 0.73 0.25 5.5 13.4 64.9 2.72 LM V STY 3544 0.04 0.04 3.2 6.7 67.5 2.71 LMSTY 3545 0.08 0.06 2.2 0.0 67.5 2.72 LM PP FOSS STY 3546 0.07 0.05 6.3 6.6 49.4 2.72 LM SL/V FOSS STY 3547 1.60 1.60 6.9 0.0 59.4 2.69 LM FOSS 3548 0.19 0.13 5.7 3.7 66.5 2.71 LM FOSS 3549 0.18 0.12 5.0 0.0 72.0 2.71 LM VF PP FOSS 3550 0.01 0.01 3.1 0.0 68.1 2.75 LM PP FOSS STY 3551 0.02 0.02 3.2 0.0 59.4 2.69 LM PP FOSS STY 3552 0.10 0.07 3.5 0.0 66.7 2.70 LM SLA/ STY 3553 4.60 0.58 4.8 4.3 69.3 2.74 LM VF PP FOSS 3554 0.23 0.22 5.4 0.0 56.9 2.71 LM V FOSS 3555 0.13 0.11 3.7 5.6 62.1 2.74 LM SLA/ FOSS 3556 0.17 0.14 5.2 0.0 65.0 2.71 LM PP FOSS STY 3557 0.39 0.33 5.4 7.7 57.7 2.72 LM V FOSS STY 3558 1.20 0.99 4.9 8.6 51.4 2.72 LM SLA/ FOSS STY 3559 0.67 0.66 7.9 2.6 61.8 2.72 LM PP FOSS STY 3560 0.55 0.54 8.0 0.0 63.9 2.72 LM 3561 0.26 0.26 8.3 2.5 69.5 2.75 LMVF 3562 0.15 0.12 2.9 0.0 65.8 2.74 LM PP FOSS STY 3563 0.06 0.06 6.2 0.0 40.9 2.73 LM SLA/ FOSS STY 3564 0.09 0.05 6.1 3.4 68.9 2.72 LM FOSS STY 3565 0.20 0.17 5.8 3.6 67.9 2.72 LMV

204 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3566 0.03 0.03 5.7 3.7 66.1 2.71 LM PP FOSS 3567 0.10 0.07 3.2 0.0 74.0 2.71 LMSL/V 3568 0.04 0.04 3.8 0.0 66.9 2.72 LMSLA/ 3569 2.10 0.07 3.1 6.8 60.9 2.72 LM SLA/ FOSS 3570 0.29 0.24 6.4 6.5 58.6 2.71 LM SLA/ STY 3571 6.20 5.60 9.4 9.7 32.3 2.71 LM SLA/ STY 3572 0.55 0.42 7.2 12.9 43.0 2.69 LMV 3573 0.65 0.39 8.2 11.3 42.8 2.72 LM PP FOSS 3574 0.19 0.18 3.8 0.0 60.4 2.74 LM SLA/ PP STY 3575 0.05 0.05 2.7 0.0 47.2 2.72 LM PP FOSS 3576 0.07 0.06 5.3 0.0 63.3 2.73 LM SLA/ FOSS 3577 2238 1527 6.7 3.1 49.5 2.75 LMSLA/ 3578 1.80 1.80 6.9 3.0 56.9 2.74 LM V STY 3579 0.51 0.05 5.9 7.1 53.2 2.73 LM SL/SHY FOSS 3580 0.21 0.21 4.1 0.0 61.9 2.72 LM SL/F PP FOSS 3581 0.67 0.67 4.7 0.0 62.7 2.71 LMSTY 3582 0.53 0.35 7.1 2.9 51.8 2.72 LM V FOSS 3583 0.23 4.70 7.3 2.9 57.4 2.72 LM SLA/ FOSS 3584 0.51 0.32 5.9 0.0 68.1 2.71 LM V FOSS

205 Permit # 36228 Breedlove Unit Mt Pleasant Field Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3543 370 192 3.9 0 42.1 2.71 LM VF V FOSS STY 3544 38 16 5 0 45.8 2.72 LM V PP STY 3545 1.5 0.47 8.9 18.2 47.9 2.7 LMVPP 3546 0.6 0.6 9.3 50.4 19.7 2.7 LMPP 3547 2 1.7 4.5 4.7 79.9 2.71 LM V PP FOSS 3548 63 45 7.8 20.9 47.1 2.7 LM V FOSS STY 3549 0.39 0.36 3.3 0 39 2.7 LM V STY 3550 236 11 7.9 15.4 48.8 2.71 LM V FOSS STY 3551 332 27 7.2 0 53.6 2.72 LM V FOSS STY 3552 17 0.72 8.5 16.9 53.1 2.7 LM V FOSS STY 3553 0.23 0.09 6.2 20.2 43.8 2.71 LM V STY *3554 0.01 3.8 11.2 67.1 2.71 LM V PP STY 3555 0.03 0.03 4.8 8.8 61.3 2.71 LM PP FOSS 3556 0.05 0.05 3.1 0 54.4 2.72 LM *3557 50 11.9 10.1 48.8 2.71 LM VFV FOSS STY 3558 1.2 0.49 10 21.6 49.4 2.71 LM V FOSS STY *3559 0.1 4.5 32.5 32.5 2.71 LMPP 3560 0.07 0.03 2.7 0 71.8 2.71 LM SLA/ PP STY 3561 2.8 1 2.6 0 73.8 2.72 LM SLA/ PP STY 3562 0.19 0.11 4 0 62.1 2.71 LM PP STY *3563 0.05 2.6 0 80.3 2.71 LMVF *3564 71 12.2 11.4 39 2.71 LM VF V FOSS STY *3565 0.93 13 9.2 50.5 2.71 LMVFVSH-INCL 3566 0.48 0.45 6.4 3.2 54.5 2.72 LM 3567 0.61 0.5 14 8.4 50.4 2.71 LM *3568 0.84 13.2 26.9 41.8 2.71 LM *3569 0.34 7.7 2.6 71.4 2.7 LM SL/F PP *3570 0.07 8.6 0 63.7 2.71 LM SL/F PP 3571 0.04 0.04 8.1 0 40.1 2.72 LMPP *3572 0.35 8.6 8.2 54.2 2.71 LM VF STY *3573 0.1 9.5 42.4 46.7 2.7 LM PP FOSS 3574 LOST CORE 3581 13 11 9.4 17.2 38.7 2.7 LMVSH-INCL 3582 4.8 2.9 7.7 37.7 35 2.68 LM V FOSS 3583 0.1 0.04 3.8 0 49.2 2.69 LM SL/SHY SLA/ FOSS *3584 0.01 2.5 0 84.7 2.72 LM FOSS STY *3585 0.01 2.9 7.4 66.5 2.71 LM SH-INCL FOSS 3586 5.7 5.3 12 14.8 36.2 2.73 LM SL/SHY SLA/ FOSS 3587 1.8 1.6 11.9 22.8 22.8 2.7 LM V FOSS

206 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3588 1.9 0.84 4.1 40.7 30.5 2.69 LM SL/SHY V FOSS 3589 0.43 0.43 10.4 33.6 35.4 2.67 LM V FOSS 3590 15 2.7 3.8 11.1 50 2.7 LM V FOSS STY 3591 0.04 0.03 6 3.5 62.6 2.72 LM 3592 0.09 0.07 6.6 3.2 66.5 2.73 LM 3593 0.1 0.01 2.1 10 60 2.71 LM SHLAM STY 3594 562 0.27 3 0 69.8 2.72 LM VF FOSS 3595 2.7 0.05 3.8 0 68.1 2.72 LM VF FOSS STY 3596 246 183 3.4 0 43.3 2.7 LMVSH-INCLSTY 3597 3.7 0.09 6.1 6.8 58.1 2.72 LMVSH-INCLSTY 3598 15 14 5.2 0 43.3 2.71 LMVSH-INCLSTY 3599 0.03 0.01 5.3 3.9 66.7 2.7 LM V FOSS 3600 260 199 5.3 0 66.5 2.71 LM V FOSS 3601 3.7 0.5 5.8 3.8 60.9 2.7 LM V FOSS 3602 0.13 0.05 5.8 7.2 60.8 2.7 LMPPV 3603 0.28 0.2 11.2 18.7 30.2 2.72 LM V FOSS STY 3604 1.4 0.33 6 12 51.3 2.72 LMVFV 3605 4.7 0.23 6.5 3.2 47.4 2.71 LM VF V PP FOSS 3606 0.89 0.33 4.9 0 42 2.71 LM VF PP FOSS STY 3607 0.1 0.03 2.8 0 68.2 2.72 LMM 3608 0.08 0.08 2.2 0 57.5 2.71 LM SL/V FOSS STY 3609 0.03 0.03 1.8 0 58 2.73 LMPP 3610 0.06 0.04 7.6 0 64 2.72 LM PP STY 3611 0.14 0.1 7.2 9.9 36.9 2.71 LM SLA/ FOSS STY 3612 0.37 0.37 9.4 7.6 41.1 2.71 LM SLA/ FOSS STY *3613 0.08 8.8 0 55.8 2.72 LM V FOSS 3614 280 228 10 7.1 42.4 2.73 LM V FOSS 3615 1 0.91 11.3 1.8 58.6 2.71 LM V PP FOSS STY 3616 0.77 0.44 10.8 3.7 52 2.73 LM V FOSS STY 3617 0.08 0.08 7.8 2.6 57.9 2.71 LMSLA/ FOSS 3618 3 2.1 7.5 5.5 57.7 2.69 LM SLA/ PP FOSS STY 3619 266 232 7.9 5.2 54.6 2.74 LM V FOSS *3620 0.14 8.2 2.5 57.5 2.71 LM V PP FOSS

207 Permit # 36204 Gwaltney, VM Mt Pleasant Field Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3597 0.13 0.05 1.3 16.5 33.0 2.71 LM,SHY,FOSS 3598 1.70 1.50 2.1 46.2 20.5 2.69 LM,SL/SHY,SHLAM 3599 0.07 0.04 1.3 32.2 16.1 2.67 LM,SHY,FOSS,STY 3600 0.16 0.10 2.9 51.7 7.4 2.69 LM, SHY, FOSS 3601 0.77 0.62 1.9 50.7 22.5 2.65 LM,SHY,SHLAM,FOSS 3602 0.56 0.14 1.9 51.7 11.5 2.67 LM,SHY,SHLAM,FOSS 3603 0.27 0.06 1.2 17.8 35.6 2.69 LM, SHY, SHLAM, 3604 0.08 0.05 2.4 9.0 44.8 2.70 LM, SL/SHY,VF.FOSS, 3605 0.14 0.14 1.6 13.7 54.9 2.68 LM,VF 3606 0.12 0.06 2.0 10.6 42.6 2.70 LM,SL/SHY,STY 3607 0.08 0.05 1.0 0.0 21.0 2.70 LM.SL/SHY 3608 0.13 0.09 1.8 12.0 48.1 2.71 LM,SL/SHY,FOSS 3609 0.43 0.37 2.7 27.9 39.8 2.70 LM,VF,PP,STY 3610 0.04 0.04 2.1 10.2 51.2 2.70 LM.FOSS 3611 0.39 0.10 2.7 15.8 39.4 2.72 LM/VF 3612 0.10 0.05 1.8 12.2 48.9 2.67 LM 3613 0.09 0.03 2.0 10.6 52.8 2.67 LM,VF 3614 0.13 0.11 2.4 9.1 54.4 2.69 LM.PP.STY 3615 4.40 2.90 0.8 0.0 28.4 2.68 LM.VF.STY 3616 0.09 0.08 1.1 0.0 20.3 2.70 LM.STY 3617 0.06 0.03 1.9 0.0 66.5 2.67 LM.STY 3618 0.08 0.04 2.6 8.3 58.2 2.70 LM.PP.STY 3619 0.37 0.21 8.5 4.7 16.5 2.71 LM,SLA/,STY 3620 1.40 1.20 4.9 19.2 29.8 2.70 LM,SLA/,STY 3621 0.05 0.03 3.9 10.9 38.0 2.71 LM.PP.STY 3622 0.04 0.04 2.6 8.2 65.3 2.70 LM.PP.STY 3623 0.27 0.07 4.2 10.1 50.4 2.70 LM.PP.STY 3624 0.49 0.17 1.3 0.0 16.1 2.70 LM.PP.STY 3625 0.30 0.30 2.3 0.0 54.8 2.73 LM.STY 3626 0.16 0.13 4.3 29.2 19.5 2.70 LM.SLA/.STY 3627 0.05 0.01 3.0 14.0 34.9 2.69 LM.PP.STY 3628 0.08 0.05 3.6 20.7 53.2 2.71 LM.FOSS 3629 8.00 0.99 1.9 0.0 66.5 2.72 LM.VF 3630 0.29 0.07 2.7 7.8 54.9 2.69 LM.VF.PP.STY 3631 0.10 0.07 4.2 30.2 20.1 2.70 LM.PP 3632 0.54 0.41 3.8 24.9 27.7 2.70 LM.PP.STY 3633 0.01 2.4 0.0 54.1 2.72 LM 3634 0.43 0.21 2.9 0.0 51.6 2.72 LM.VF.STY 3635 0.19 0.14 1.8 0.0 48.2 2.72 LM.FOSS

208 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3636 0.07 0.03 4.5 9.3 28.0 2.70 LM.PP.STY 3637 0.06 0.03 2.9 14.8 51.8 2.70 LM.PP 3638 0.07 0.03 2.0 0.0 54.4 2.71 LM 3639 0.02 0.01 3.5 12.0 36.1 2.70 LM.SHLAM 3640 0.25 0.13 3.3 6.4 32.0 2.71 LM.PP.STY 3641 0.06 0.03 1.7 0.0 51.3 2.70 LM.VF.FOSS 3642 0.01 3.1 7.0 63.2 2.73 LM 3643 2.9 7.3 58.5 SAMPLE MISSING 3644 1.4 15.3 30.5 SAMPLE MISSING 3645 0.13 0.12 1.7 12.3 24.6 2.75 LM.SL/SHY.VF 3646 0.01 2.2 9.9 49.4 2.72 LM 3647 3.20 1.10 1.9 0.0 57.0 2.71 LM.VF.STY 3648 2.3 9.4 56.5 LM,FOSS,TBFA 3649 0.16 0.01 3.2 6.7 40.0 2.70 LM.VF.STY 3650 0.01 0.01 1.7 25.3 25.3 2.72 LM 3651 0.01 0.01 2.5 8.5 51.2 2.69 LM.SL/SHY.VF 3652 0.20 0.13 2.7 7.8 54.9 2.70 LM.VF.STY 3653 0.13 0.08 3.4 22.1 50.5 2.71 LM.VF.STY 3654 0.10 0.07 2.3 9.2 45.8 2.69 LM.VF.STY 3655 0.06 0.06 2.2 9.7 19.5 2.72 LM.SL/SHY.STY

209 Permit # 36049 Mcclintic # 4 Mt Pleasant Field Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3559 0.03 0.01 2.6 28.5 40.7 2.71 LM, SHY, FOSS, STY 3560 0.11 0.10 1.5 28.1 28.1 2.70 LM, SHY, FOSS, STY 3561 0.08 0.08 1.7 44.6 25.5 2.69 LM, SHY, FOSS, STY 3562 0.09 0.07 1.1 20.2 40.4 2.71 LM SHLAM, FOSS 3563 0.03 0.03 1.2 17.6 35.2 2.69 LM FOSS 3564 0.05 0.04 1.5 29.5 29.5 2.70 LM FOSS, STY 3565 0.04 0.04 1.9 50.3 22.4 2.68 LM SL/F, SHLAM, 3566 0.09 0.07 1.8 47.1 23.5 2.69 LM SL/SHY, SHLAM, 3567 0.07 0.07 2.7 47.4 31.6 2.65 LM SL/SHY, SHLAM, 3568 0.07 0.07 1.8 41.0 23.4 2.63 LM SL/SHY, SHLAM, 3569 0.71 0.42 4.0 10.6 47.9 2.69 LM V, FOSS 3570 0.55 0.54 6.9 17.9 26.9 2.71 LM V, FOSS, STY 3571 0.77 0.76 10.2 35.2 15.7 2.70 LM VF, SLA/, FOSS 3572 0.14 0.14 2.8 0.0 53.7 2.72 LM VF 3573 43.00 0.03 2.5 0.0 68.2 2.71 LM VF, PP, STY 3574 2.50 1.50 10.0 32.4 58.6 2.71 LM V, FOSS, STY 3575 10.00 7.50 9.5 30.1 45.1 2.71 LM V, FOSS, STY 3576 11.00 7.00 10.7 23.3 33.6 2.70 LM V, FOSS, STY 3577 0.96 0.95 7.7 15.9 37.2 2.71 LM V, STY 3578 0.67 0.67 8.1 35.4 32.9 2.69 LM SLA/, STY 3579 4.10 4.00 3.9 5.4 75.6 2.71 LM VF, SLA/, STY 3580 733 586 9.0 13.7 52.3 2.71 LM SL/F, V, STY 3581 2957 25.00 8.7 10.3 43.7 2.71 LM VF, V 3582 237 123 10.8 14.8 42.6 2.71 LM V 3583 12.00 2.90 7.8 18.3 39.2 2.69 LM VF, V, STY 3584 0.09 0.04 5.8 16.2 28.8 2.71 LM PP 3585 0.50 0.48 8.0 61.4 12.8 2.68 LM PP 3586 0.02 0.01 2.6 28.6 16.3 2.73 LM VF, PP 3587 4112 0.07 4.6 16.1 55.3 2.73 LM VF, PP 3588 44.00 22.00 8.3 19.5 43.9 2.72 LM 3589 1.30 1.10 4.6 15.9 45.3 2.70 LM VF, SLA/, STY 3590 280 0.05 6.0 24.1 27.5 2.71 LM VF, PP 3591 0.01 0.01 4.3 29.5 49.1 2.70 LM 3594 0.25 0.14 9.2 32.6 13.0 2.66 LM SLA/ 3595 22.00 0.64 3.7 5.8 40.4 2.71 LM PP 3596 0.03 0.01 3.6 0.0 47.4 2.67 LM SL/SHY, SLA/ 3597 0.80 0.39 4.8 8.6 30.2 2.70 LM V, STY 3598 6.6 6.2 21.8 TBFA 3599 4.00 0.62 5.5 17.0 53.0 2.66 LM, V, STY

210 Permit # 35680 Foster, Mary W Mt Pleasant Field Midland County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3551 0.01 0.01 2.2 45.5 9.1 2.70 LM SHY SL/PYRC 3552 0.09 0.01 1.8 38.9 11.1 2.70 LM SHY FOSS STY 3553 0.16 0.05 0.7 0.0 28.6 2.69 LM SL/SHY FOSS 3554 0.04 0.03 3.6 52.8 11.1 2.70 LM SL/SHY FOSS 3555 0.04 0.04 1.8 50.0 11.1 2.67 LM SHY FOSS STY 3556 0.03 0.03 1.9 43.8 11.1 2.68 LM SHY FOSS STY 3557 0.07 0.07 2.4 54.2 8.3 2.68 LM SHY FOSS STY 3558 0.03 0.03 3.3 39.4 45.5 2.70 LM SL/SHY FOSS 3559 0.04 0.01 1.5 53.3 13.3 2.70 LM SL/SHY SL/F 3560 7.30 4.70 9.7 21.6 28.9 2.71 LM CALC V SHR S 3561 3.30 3.10 11.2 25.0 32.1 2.70 LMVSHRFOSS 3562 4.30 4.00 15.5 31.7 17.1 2.69 LMV SL/F SHR 3563 0.37 0.30 3 50.0 6.7 2.70 LM SL/SHY VF 3564 0.04 0.01 0.6 0.0 66.7 2.70 LMVF 3565 14.00 13.00 10 12.0 26.0 2.71 LM V SHR STY 3566 0.62 0.11 6.1 19.7 31.1 2.70 LM VF SLA/ PP STY 3567 1.20 0.02 4.1 53.7 22.0 2.70 LM VF PP FOSS STY 3568 0.55 0.34 1.5 26.7 13.3 2.70 LM VF PP SHR FOSS 3569 0.12 0.12 0.6 0.0 33.3 2.74 LM SL/SHY SL/F 3570 0.24 0.12 3.2 21.9 18.8 2.74 LM SL/SHY VF PP 3571 0.10 0.06 3.5 37.1 37.1 2.70 LM SL/SHY SL/F PP 3572 0.08 0.05 2.5 40.0 16.0 2.70 LM PP FOSS STY 3573 0.63 0.18 2.2 40.2 17.9 2.70 LM SL/F SL/V PP 3574 15.00 10.00 5.1 7.8 56.9 2.72 LM VF V FOSS 3575 22.00 8.10 4.9 8.2 24.5 2.71 LM PYRC V STY 3576 20.00 13.00 11.1 10.5 22.7 2.70 LMV SHR 3577 14.00 8.00 3.9 56.4 15.4 2.67 LMV SHR 3578 0.73 0.64 1.9 36.8 21.1 2.70 LM VF PP SHR STY 3579 0.20 0.20 11.3 17.7 27.4 2.70 LM SL/F PP STY 3580 4.10 3.30 4.2 21.4 31.0 2.69 LM SHY VF PP STY 3581 1.60 0.86 1.9 0.0 57.9 2.69 LM VF PP SHR STY 3582 0.08 0.05 1.6 0.0 37.5 2.69 LM SL/F PP FOSS 3583 0.06 0.03 1.7 12.3 36.8 2.71 LM PP STY 3584 0.22 0.07 3.8 31.6 36.8 2.70 LMPP 3585 0.03 0.01 2 0.0 40.0 2.71 LM VF PP FOSS 3586 0.87 0.82 9.1 33.0 13.2 2.70 LM PP FOSS

211 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3587 0.15 0.13 12.4 29.8 15.3 2.69 LM PP SHR FOSS 3588 0.09 0.03 3.8 18.4 44.7 2.70 LM PP SHR STY 3589 0.01 0.01 2.6 0.0 42.3 2.71 LM VF PP STY 3590 9.60 0.08 4.6 19.6 37.0 2.70 LM VF V FOSS STY 3591 3.80 2.40 4.8 29.7 25.5 2.68 LMV SL/F SHR STY 3592 0.04 0.03 4 41.1 15.4 2.71 LM PP FOSS STY 3593 0.02 0.01 2.8 0.0 69.1 2.71 LM FOSS STY 3594 0.10 0.10 3.4 12.5 37.4 2.70 LM PP FOSS 3595 1.20 0.01 2.1 0.0 70.2 2.72 LM VF STY 3596 0.02 0.02 1 0.0 21.7 2.71 LM PP STY 3597 0.07 0.02 1.6 0.0 43.3 2.71 LM VF PP STY 3598 0.02 0.02 7 5.8 20.3 2.68 LM SL/F PP 3599 0.03 0.03 3.5 11.7 17.6 2.70 LM SL/F PP 3600 0.12 0.03 5.1 8.2 37.1 2.68 LM V STY 3601 0.07 0.03 4.4 9.5 61.6 2.71 LM CALC V SL 3602 0.30 0.09 5.8 7.2 54.3 2.72 LM VF PP SHR 3603 0.16 0.13 2.9 0.0 57.1 2.70 LM SL/ANHY 3604 0.36 0.22 3.3 22.5 54.4 2.71 LMV 3605 0.08 0.03 4.7 9.0 53.9 2.73 LM PP STY 3606 0.11 0.05 2.3 18.8 28.1 2.71 LM VF SHLAM STY 3607 1.40 0.20 3.9 0.0 43.0 2.72 LM SL/F PP 3608 1.30 0.70 3.7 11.4 22.8 2.70 LM VF PP 3609 0.02 0.02 1.2 0.0 17.3 2.69 LM SL/SHY 3610 0.10 0.07 0.9 0.0 23.1 2.69 LMVF

212 Permit # 35540 SMITH, VERA A. Mt Pleasant Field Isabella County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3556 0.01 0.01 2.8 14.3 28.6 2.68 LM, SHY, SHLAM, 3557 0.01 0.01 3.2 12.5 46.9 2.67 LM, SHY, SHLAM, 3558 0.01 0.01 2.9 0.0 31.0 2.68 LM SL/F, SHLAM, 3559 0.01 0.01 2 20.0 30.0 2.67 LM FOSS, STY 3560 0.01 0.01 2.4 16.7 16.7 2.69 LM SHLAM, FOSS 3561 0.01 0.01 1.9 21.1 21.1 2.69 LM SL/SHY, FOSS, 3562 0.01 0.01 1.7 47.1 23.5 2.73 LM SL/SHY, FOSS, 3563 0.01 0.01 1 20.0 20.0 2.71 LM FOSS, STY 3564 0.01 0.01 2.5 16.0 32.0 2.7 LM FOSS, STY 3565 0.01 0.01 1.3 15.4 46.2 2.7 LM FOSS, STY 3566 0.01 0.01 1.7 23.5 23.5 2.69 LM SL/SHY, FOSS, 3567 0.01 0.01 2 10.0 30.0 2.69 LM SL/SHY, FOSS, 3568 0.02 0.01 2 35.0 20.0 2.71 LM FOSS 3569 0.01 0.01 1.4 14.3 14.3 2.7 LM FOSS 3570 0.01 0.01 1.9 10.5 31.6 2.7 LM FOSS, STY 3571 0.01 0.01 1.3 15.4 46.2 2.69 LM FOSS, STY 3572 0.01 0.01 1.2 16.7 33.3 2.69 LM FOSS, STY 3573 0.02 0.01 1.2 16.7 33.3 2.7 LM SL/F, STY 3574 0.01 0.01 1.2 0.0 33.3 2.69 LM SL/F, FOSS, STY 3575 0.01 0.01 0.5 0.0 40.0 2.69 LM SL/SHY, FOSS, 3576 0.01 0.01 0.4 0.0 50.0 2.69 LM SL/SHY, FOSS, 3577 0.01 0.01 1.4 14.3 28.6 2.69 LM SL/SHY, FOSS, 3578 0.01 0.01 1 40.0 20.0 2.69 LM FOSS, STY 3579 0.01 0.01 0.9 22.2 22.2 2.68 LM FOSS, STY 3580 0.04 0.01 1.3 30.8 30.8 2.69 LM FOSS, STY 3581 0.01 0.01 0.8 25.0 25.0 2.68 LM SL/SHY, FOSS, 3582 0.01 0.01 1 20.0 20.0 2.68 LM FOSS, STY 3583 0.03 0.01 0.9 22.2 22.2 2.68 LM FOSS, STY 3584 0.01 0.01 1.4 28.6 26.7 2.66 LM SL/SHY, FOSS, 3585 0.01 0.01 1.1 33.3 16.6 2.7 LM FOSS, STY 3586 0.01 0.01 1.1 18.2 18.2 2.69 LM FOSS, STY 3587 0.01 0.01 0.8 25.0 25.0 2.7 LM FOSS, STY 3588 0.03 0.03 2.8 28.6 21.4 2.68 LM SLA/, SH-INCL, 3589 0.02 0.01 2.6 0.0 65.4 2.68 LM PP, STY 3590 0.03 0.01 2.3 0.0 65.2 2.68 LM PP, SH-INCL, 3591 0.03 1.5 0.0 40.0 2.65 LM 3592 0.01 0.01 1.9 0.0 47.4 2.69 LM, SH-INCL

213 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG FLD OIL WATER GRAIN DESCRIPTION 3593 0.01 0.01 0.8 0.0 25.0 2.7 LM, SH-INCL, FOSS 3594 0.27 0.12 8.7 10.3 23.0 2.7 LM, V, SH-INCL, STY 3595 0.03 0.01 6.1 14.8 44.3 2.67 LM, PP 3596 0.01 0.01 1.5 0.0 40.0 2.66 LM, PP 3597 0.02 0.01 1.9 10.5 47.4 2.68 LM 3598 0.01 0.01 2 0.0 65.0 2.71 LM, FOSS, STY 3599 0.04 0.01 2.3 0.0 65.2 2.68 LM, PP, STY 3600 0.13 0.09 5.2 7.7 23.1 2.7 LM, V, SH-INCL, STY 3601 0.07 0.02 4.9 8.1 24.5 2.68 LM, V, STY 3602 0.07 0.02 3.3 12.1 51.5 2.68 LM, VF, PP, STY 3603 0.02 0.01 5.8 12.1 27.6 2.66 LM, PP 3604 0.01 0.01 2.5 0.0 60.0 2.69 LM, PP, STY 3605 0.1 5.4 7.4 29.6 2.69 LM, V, STY 3606 0.08 0.04 4.9 14.3 24.5 2.66 LM, V

214 Permit U 36730 Fitzwater 6. South buckeye Field Gladwin County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3560 0.1 0.1 1.0 1.9 65.2 2.71 LS, F/XL, GY 3561 0.1 0.1 1.1 1.5 62.1 2.70 LS, F/XL, GY 3562 0.1 0.1 0.9 18.3 62.5 2.69 LS, F/XL GY 3563 4.3 0.1 2.1 19.3 65.8 2.70 LS F/XL GY 3564 21.0 21.0 6.5 12.4 42.7 2.70 LS F/XL SLA/UG, FOS, 3565 794.0 449.0 8.1 13.6 44.3 2.70 LS F/XL FOS, GY 3566 944.0 755.0 6.6 9.2 29.4 2.70 LS F/XL FOS, GY 3567 401.0 63.0 7.1 11.8 38.2 2.70 LS F/XL SLA/UG, FOS, 3568 52.0 0.3 3.4 17.8 52.1 2.70 LS F/XL FOS, GY 3569 87.0 32.0 7.1 13.7 41.0 2.69 LS F/XL SLA/UG, FOS, 3570 32.0 26.0 10.3 13.3 39.8 2.69 LS F/XL FOS, GY 3571 51.0 6.7 12.9 16.4 35.3 2.69 LS F/XL FOS, GY 3572 351.0 47.0 15.4 17.7 38.1 2.69 LS F/XL FOS, GY 3573 7.6 1.8 2.8 20.5 44.4 2.69 LS F/XL FOS, GY 3574 1.2 0.4 3.8 12.1 62.8 2.70 LS F/XL FOS, GY 3575 14.0 9.9 4.8 13.3 68.3 2.70 LS F/XL SLA/UG, FOS, 3576 22.0 2.4 5.4 9.3 47.2 2.69 LS F/XL SLA/UG, FOS, 3577 521.0 277.0 10.1 20.3 39.6 2.69 LS F/XL SLA/UG, FOS, 3578 31.0 11.0 7.5 24.8 48.2 2.68 LS F/XL SLA/UG, FOS, 3579 52.0 4.2 10.1 19.6 38.4 2.68 LS F/XL SLA/UG, FOS, 3580 22.0 10.0 4.6 5.5 56.8 2.69 LS F/XL SLA/UG, GY 3581 15.0 13.0 14.2 4.1 42.4 2.72 LS F/XL SLA/UG, FOS, 3582 25.0 12.0 5.4 5.4 56.6 2.69 LS F/XL VUG, FOS, 3583 4.9 4.4 4.1 16.7 60.4 2.67 LS F/XL GY 3584 5.7 5.9 6.8 65.6 2.70 LS F/XL SLA/UG, 3585 6.0 4.8 1.6 6.9 79.9 2.69 LS F/XL SLA/UG, FOS, 3586 25.0 11.0 9.5 4.5 52.5 2.69 LS F/XL SLA/UG, FOS 3587 3.8 2.8 1.1 4.7 55.2 2.69 LS F/XL FOS, GY 3588 0.2 0.2 1.3 4.3 40.6 2.69 LS F/XL FOS, GY 3589 5.1 2.4 5.7 3.2 31.2 2.69 LS F/XL VUG, FOS, 3590 0.2 0.1 2.5 6.8 68.5 2.69 LS F/XL SLA/UG, FOS, 3591 0.1 0.1 1.2 3.3 50.0 2.69 LS F/XL GY 3592 0.1 0.1 1.5 2.6 44.2 2.69 LS F/XL GY 3597 0.1 0.1 1.7 4.7 52.2 2.69 LS F/XL GY 3598 0.1 0.1 1.6 4.0 45.1 2.69 LS F/XL GY 3600 0.4 0.3 4.7 1.8 51.9 2.69 LS F/XL GY 3601 0.1 0.1 3.1 2.1 59.5 2.69 LS F/XL FOS, GY 3622 7.6 4.0 5.8 1.1 49.8 2.69 LS F/XL FOS, GY 3623 1.3 1.3 5.8 1.4 48.5 2.69 LS F/XL FOS, GY

215 Permit# 43383 Nusbaum Kern 3-W. South buckeye Field Gladwin County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3557 1.9 1.3 5.4 31.6 59.3 2.711 LS 3558 0.1 0.1 0.4 25.3 50.3 2.733 LS 3559 0.7 0.3 2.7 0.0 38.9 2.690 LS 3560 2.6 0.5 2.2 5.9 33.7 2.698 LS 3561 15.0 0.3 2.0 9.1 81.4 2.697 LS 3562 0.1 0.1 2.6 0.0 38.6 2.691 LS 3563 0.6 0.5 3.3 0.0 31.5 2.685 LS 3564 4.2 2.4 2.9 4.9 39.2 2.690 LS 3565 22.0 21.0 15.7 26.9 54.5 2.652 LS, FOSS 3567 5.1 3.2 6.1 17.3 60.6 2.689 LS, FOSS 3568 185.0 34.0 8.3 22.2 30.2 2.693 LS, FOSS 3569 1.6 0.6 2.0 16.1 51.7 2.690 LS, FOSS 3570 14.0 11.0 4.3 21.9 41.9 2.692 LS, FOSS 3571 1.4 1.2 5.4 9.6 30.7 2.696 LS, FOSS 3572 0.5 0.3 4.3 13.6 27.3 2.690 LS, FOSS 3573 14.0 6.8 70.0 12.6 24.6 2.681 LS, FOSS 3574 1.0 30.0 8.5 15.3 27.8 2.677 LS 3575 527.0 456.0 8.7 15.1 32.0 2.678 LS, FOSS 3576 0.1 0.1 2.6 17.8 33.4 2.690 LS 3577 0.1 0.1 1.3 0.0 49.9 2.774 LS 3578 0.2 0.2 2.0 0.0 21.7 2.700 LS 3579 0.4 0.1 2.4 0.0 27.4 2.697 LS 3580 0.1 0.1 1.9 0.0 32.3 2.703 LS 3581 0.1 0.1 1.6 6.8 68.0 2.699 LS 3582 0.4 0.0 1.6 6.7 46.6 2.699 LS 3583 1.0 0.9 2.8 3.7 22.3 2.703 LS 3584 0.3 0.3 3.7 2.9 37.1 2.685 LS 3585 0.9 0.5 2.3 3.2 27.9 2.687 LS 3586 0.5 0.1 1.5 7.3 62.7 2.699 LS 3587 1.4 0.7 4.2 12.5 35.0 2.692 LS 3588 0.2 0.1 1.6 15.5 43.5 2.691 LS 3589 0.1 0.0 1.5 14.8 41.7 2.695 LS 3590 0.2 0.1 3.1 16.7 20.0 2.689 LS 3591 0.4 0.3 1.7 15.7 25.2 2.680 LS 3592 0.1 0.1 1.0 0.0 43.7 2.697 LS 3593 0.1 0.1 0.9 11.8 70.9 2.699 LS 3594 0.8 0.0 1.3 8.2 82.0 2.700 LS 3595 0.0 0.0 1.8 0.0 59.5 2.704 LS 3596 0.2 0.1 1.8 5.9 59.0 2.717 LS

216 Permit#32780 State Buckeye B-6, North Buckeye Field Gladwin County Michigan

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3615 0.7 0.1 0.5 15.0 21.7 2.72 LM 3616 156 21 7.2 30.1 40.5 2.76 LM, PYRITE, VGY 3617 606 606 11.7 30.7 41.3 2.76 LM, PYRITE, VGY 3618 348 217 10.0 32.1 49.3 2.70 LM, VGY 3619 899 862 13.2 26.6 40.5 2.73 LM, VGY 3620 519 437 11.5 27.9 42.7 2.74 LM, VGY 3621 267 233 10.8 27.8 53.7 2.70 LM, VGY 3622 162 159 11.8 27.3 52.8 2.72 LM, VGY 3623 102 99.0 12.1 27.6 53.3 2.73 LM, VGY 3624 23 15.0 11.0 14.8 67.9 2.72 LM, VGY 3625 24 19.0 11.1 16.6 76.4 2.73 LM, VGY 3626 19 13.0 12.0 14.8 68.9 2.73 LM, VGY 3627 5 5.0 9.3 17.5 67.4 2.72 LM, VGY 3628 1893 62.0 9.6 14.2 54.8 2.74 LM VGY, V/F 3629 321 250.0 11.1 15.7 60.5 2.71 LM, VGY 3630 373 311.0 10.8 23.8 62.7 2.72 LM, VGY 3631 0.6 9.2 22.5 59.3 2.72 LM, VGY 3632 0.4 9.2 23.1 59.8 2.71 LM, VGY 3633 0.7 0.3 9.6 29.1 66.9 2.71 LM, VGY 3634 907 907 12.3 22.3 51.3 2.72 LM, VGY 3635 0.2 5.6 25.3 58.2 2.72 LM, VGY 3636 0.1 9.9 14.2 60.7 2.73 LM, VGY 3637 15.0 3.4 8.9 14.3 60.9 2.74 LM, VGY 3638 13.0 8.2 11.4 13.8 59.1 2.75 LM, SLA/GY 3639 13.0 1.2 9.0 25.5 52.8 2.73 LM, VGY 3640 161.0 155 13.1 23.8 49.3 2.74 LM, VGY 3641 136.0 120 12.2 24.5 50.0 2.72 LM, VGY 3642 3.2 2.7 9.6 37.9 39.3 2.71 LM, VGY 3643 0.5 0.4 9.7 37.6 38.9 2.73 LM, VGY 3644 0.3 0.2 6.4 4.3 76.6 2.71 LM, STY, VGY 3645 640.0 0.3 6.9 4.1 72.0 2.75 LM, V/F 3646 0.1 5.9 4.0 72.1 2.74 LM 3647 0.1 5.8 4.2 74.3 2.73 LM 3648 0.4 0.1 6.1 14.7 73.2 2.73 LM 3649 3.3 0.1 2.4 13.4 67.2 2.73 LM, SLA/GY 3650 0.1 0.1 1.0 12.7 62.7 2.73 LM 3651 0.1 0.1 2.2 13.5 58.7 2.74 LM

217 PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3652 0.3 0.2 2.0 17.1 71.4 2.73 LM 3653 0.1 0.1 0.9 13.0 60.0 2.73 LM 3654 0.2 0.1 2.0 14.7 64.7 2.73 LM 3655 182.0 0.1 7.0 9.2 52.3 2.77 LM, V/F 3656 0.2 0.1 6.0 10.9 62.1 2.72 LM, STY, SLA/GY, V/ 3657 0.1 0.1 5.8 10.1 58.1 2.73 LM, SLA/GY, V/F 3658 0.1 0.1 1.9 10.0 61.3 2.74 LM, SLA/GY, V/F 3659 0.2 0.1 8.0 7.9 47.9 2.72 LM, SLA/GY 3660 0.1 0.1 4.9 10.2 61.7 2.73 LM 3661 0.6 0.1 6.2 6.2 71.8 2.72 LM, SL/VGY.V/F 3662 0.1 0.1 4.5 6.7 77.5 2.71 LM, FOSS, VGY, V/F 3663 0.1 0.1 6.5 3.4 74.2 2.72 LM, FOSS, VGY, V/F 3664 0.1 0.1 6.3 3.0 64.9 2.72 LM, FOSS, SLA/GY 3665 0.1 0.1 6.0 2.9 64.8 2.73 LM, FOSS, SLA/GY 3666 0.8 0.1 11.6 6.4 49.0 2.73 LM, SLA/GY 3667 0.4 0.1 7.6 7.0 53.8 2.72 LM, SLA/GY 3668 0.1 0.1 8.3 7.3 55.4 2.71 LM, VGY 3669 0.1 0.1 11.0 9.6 47.6 2.72 LM, VGY 3670 0.1 0.1 9.0 10.6 52.6 2.73 LM, VGY 3671 0.1 0.1 3.8 18.5 39.2 2.72 LM, VGY 3672 0.1 0.1 0.8 25.8 54.2 2.72 LM, VGY

218 Permit#35720 Hutsonl-2., Butman Gladwin County MI

PERM FLUID FLUID PERM 90 PORO SAT SAT DENSITY DEPTH MAX DEG GEX OIL WATER GRAIN DESCRIPTION 3656.0-57.0 0.1 0.1 1.1 8.8 88.2 2.71 LS 3657.0-58.0 1.7 0.5 0.5 8.3 78.3 2.70 LS 3658.0-59.0 0.1 0.1 1.0 8.7 87.3 2.70 LS 3659.0-60.0 0.1 0.1 0.8 7.3 82.0 2.70 LS 3660.0-61.0 0.1 0.1 3.0 21.7 46.6 2.70 LS 3661.0-62.0 0.1 0.1 3.0 20.8 44.6 2.69 LS 3662.0-63.0 0.1 0.1 0.7 7.5 82.5 2.70 LS 3663.0-64.0 0.1 0.1 1.3 10.8 72.4 2.71 LS 3664.0-65.0 0.1 0.1 2.3 10.0 68.1 2.70 LS 3665.0-66.0 0.1 0.1 0.5 12.5 78.8 2.70 LS 3666.0-67.0 0.1 0.1 0.7 12.9 77.1 2.71 LS 3667.0-68.0 0.1 0.1 0.9 5.0 91.1 2.70 LS 3668.0-69.0 0.1 0.1 2.7 12.6 74.6 2.72 LS 3669.0-70.0 0.1 0.1 0.8 5.0 88.3 2.70 LS

219 Permit#28399 Grow 4, West Branch Ogemaw CO, MI

FLUID FLUID PERM PERM PORO SAT SAT DENSITY DEPTH MAX HORIZ GEX OIL WATER GRAIN DESCRIPTION 2578.2 0.10 1.7 2578.8 0.10 3.2 2580.3 0.1 9.0 2581.3 0.2 10.1 2582.5 0.1 5.7 2584.4 0.1 8.1 2587.4 12.3 2587.4 1.0 10.9 2588.5 13.9 2588.7 1.7 12.4 2593.5 4.9 9.2 2597.9 1.8 7.4 2603.0 0.5 7.1 2607.1 7.2 2607.1 0.1 4.8 2608.6 1.1 7.6 2609.6 1.3 8.8 2610.9 0.6 8.6 2613.0 9.1 10.6 2613.2 8.9 2613.3 0.7 6.6 2614.3 6.9 11.7 2615.0 0.6 8.4 2617.2 3.7 10.6 2618.5 0.4 6.2 2621.9 6.2 7.7 2622.9 1.1 6.0 2624.0 13.0 8.9 2626.5 0.1 5.3 2628.4 0.4 5.7 2629.3 0.1 5.6 2930.9 0.4 4.4 2632.1 6.2 7.1 2635.7 8.1 2635.7 112.0 11.3 2636.0 11.3 2636.1 189.0 12.2

220 FLUID FLUID PERM PERM PORO SAT SAT DENSITY DEPTH MAX HORIZ GEX OIL WATER GRAIN DESCRIPTION 2639.3 0.5 4.8 2639.8 12.4 2639.8 14.0 10.9 2641.7 12.7 2641.7 5.7 10.7 2644.5 11.3 2644.5 29.0 10.8 2645.0 14.0 13.6 2647.0 2.4 7.5 2649.5 15.0 10.3 2651.5 0.1 6.3 2652.5 5.7 9.7 2655.2 26.0 10.9 2656.3 7.4 9.7 2657.9 0.5 7.6 2660.6 0.3 6.2 2663.1 0.9 9.8 2684.1 54.0 21.8 2687.0 0.1 5.0 2707.5 0.1 1.4 2708.7 0.1 7.7

221 Appendix E Cross-sections

Core to Log Correlation Dundee Limestone Formation

222 to

Figure E. 1. A base map with three cross-section lines strike oriented (A-A' and B-B') and dip oriented cross-section (C- C). MT PLEASANT UNIT TRACT 19 MT PLEASANT UNIT TRACT 46 MCCLINTIC MCCLINTIC MAEDER GRACE L EMMONS BROTHERS 39821 39771 36820 36367 36647 37069 A'

RGRC

DUND

Facies 6 Facies 7

to

ISABELLA ISABELLA ISABELLA ISABELLA ISABELLA ISABELLA Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Skeletal Crinoidal Wackestone Fenestral peloidal Grainstone/Packstone Skeletal Wackestone

Figure E.2. Stratigraphic cross-section (A-A') showing inferred lateral continuity of the fenestral reservoir facies (Above blue line) and skeletal wackestone facies (green line). The stratigraphic datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City/Dundee contact). The flooding surface is marked with red dashed line (FS). RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI = neutron porosity log, RHOB = bulk density log. MT. PLEASANT UNIT TRACT 52 MT PLEASANT UNIT TRACT 55 BISHOP J MCCLINTIC STATE CHIPPEWA STATE CHIPPEWA EMMONS BROTHERS 39824 39770 36854 36815 36884 36910 37069 B A <025MI> A <0.16MI> A B'

RGRC

DUND

Facies 6 Facies 7

to to

ISABELLA ISABELLA ISABELLA ISABELLA ISABELLA ISABELLA ISABELLA Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Skeletal Crinoidal Wackestone Fenestral peloidal Grainstone/Packstone Skeletal Wackestone

Figure E.3. Stratigraphic cross-section (B-B') showing inferred lateral continuity of the fenestral reservoir facies (Above blue line) and the skeletal wackestone (green line). The stratigraphic datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City/Dundee contact). The flooding surface is marked with red dashed line (FS). RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI = neutron porosity log, RHOB = bulk density log. MT. PLEASANT UNIT TRACT 21 MT PLEASANT UNIT TRACT 55 FISHER BROTHERS A SCHROT, JOHN J PFUND, W CLARK UNIT PLONA UNIT 40264 39770 37350 36983 36259 37028 36931 C# <1.18MI> A <0.72MI> A <2.40MI> £ c

RHOB RHOB RHOB

RGRC

to toOs

Flooding Surface

ISABELLA ISABELLA ISABELLA MIDLAND MIDLAND MIDLAND MIDLAND Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant Mount Pleasant

Skeletal Crinoidal Wackestone Fenestral peloidal Grainstone/Packstone Skeletal Wackestone Figure E.4. Stratigraphic cross-section (C-C) showing inferred lateral continuity of thefenestral reservoir facies(Above blue line) and skeletal wackestone (green line). The stratigraphic datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City/Dundee contact). The flooding surface is marked with red dashed line (FS). RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI = neutron porosity log, RHOB = bulk density log. METHNER S MAXWELL 37290 D'

RGRC

DUND

Flooding Surface?

LUCS

ISABELLA

Figure E.5. Stratigraphic cross-section (D-D') showing the inferred flooding surface (FS marked with red dashed line). The stratigraphic datum for the cross-section is the major flooding surface at the top of the Dundee Limestone (Rogers City/Dundee contact). RGRC = Rogers City, DUND = Dundee, LUCS= Lucas Formation, GR = gamma- ray log, NPHI = neutron porosity log, RHOB = bulk density log.

227 STROHKIRCH. A 31979

GLADWIN GLADWIN GLADWIN GLADWIN GLADWIN Buckeye North Buckeye North Buckeye North Buckeye North Buckeye North • Coral-Stromatoporoid • Fenestral peloidal • Skeletal Crinoidal F5 Stromatoporoid Boundstone • Skeletal Wackestone Wackestone Floatstone Grainstone/Packstone

Figure E.6. Stratigraphic cross-section (E-E') showing inferred lateral continuity of the fenestral reservoir facies (Above blue line). The stratigraphic datum for the cross-section is the majorflooding surface at the top of the Dundee Limestone (Rogers City/Dundee contact). The flooding surface is marked with red dashed line (FS). RGRC = Rogers City, DUND = Dundee, GR = gamma-ray log, NPHI = neutronporositylog, RHOB = bulk density log.

228