Integrated Sedimentology, Sequence Stratigraphy, and Reservoir Characterization of the Basal Spirit River Formation, West-Central Alberta

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2017 Integrated sedimentology, sequence stratigraphy, and reservoir characterization of the basal Spirit River Formation, west-central Alberta

Newitt, Dillon

Newitt, D. (2017). Integrated sedimentology, sequence stratigraphy, and reservoir characterization of the basal Spirit River Formation, west-central Alberta (Unpublished master's thesis). University of Calgary, Calgary, AB. doi:10.11575/PRISM/26573 http://hdl.handle.net/11023/3926 master thesis

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Integrated sedimentology, sequence stratigraphy, and reservoir characterization of the basal

Spirit River Formation, west-central Alberta

Dillon Jared Newitt

A THESIS

SUBMITTED TO THE FACULTY OF GRADUATE STUDIES

IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE

DEGREE OF MASTER OF SCIENCE

GRADUATE PROGRAM IN GEOLOGY AND GEOPHYSICS

CALGARY, ALBERTA

JUNE, 2017

The basal progradational Falher is comprised of five northward accreting wave- dominated deltaic shoreline parasequence sets within this study area. Well and core based sequence stratigraphy reveals broad facies belts and sharp-based shoreline parasequence sets, reflecting progradation into shallow water; and, an initial strongly progradational to subsequently dominantly aggradational parasequence set stacking pattern within the Spirit

River Formation clastic wedge. Thin sections revealed the low porosity and permeability of the sandstone due to high degree of mechanical compaction, and precipitation of cements and clays. Locally, enhanced permeability is related to early ferroan dolomite cement, even though pore filling, reduced the effects of plastic deformation of ductile grains.

Insights from this thesis provides a core and well based subsurface approach to studying ancient shoreline successions, which prograde into an epeiric sea within an active foreland basin; and, a thin section based approach to studying such tight sandstone intervals for various petrographic responses.

Acknowledgements

First and foremost, I would like to thank and acknowledge my supervisor Dr. Per

Pedersen, for all the time he has put in over the last few years providing guidance, scientific expertise, and feedback. I would not have been able to accomplish my goals and be where I am now without his endless effort, I am forever grateful. Further, thesis defense committee members Dr. John-Paul Zonneveld and Dr. Rudi Meyer for providing constructive feedback and interesting discussion points, this input further improved the quality of this thesis.

Funding for this research was provided through the Tight Oil Consortium (TOC). Without the generous support and donations from the companies within this consortium, research such as this would not be possible.

I would like to sincerely thank colleagues from Centre for Applied Basin Studies (CABS) over the past few years for important feedback and discussions on thesis work. As well, to everyone for interesting lunchtime discussions and fun outside school activities, which has made my time as a graduate student an amazing experience while building lasting friendships, in particular Emma Percy and Rebecca Englert.

To my parents, Lorne and Nola Newitt, and my brother Richard, I would like to thank for all their encouragement, support, and patience throughout the past seven years of school.

Finally, I am thankful for all the friends outside of school, and those made through my time as undergraduate at U of C. I am forever grateful for the people in my life.

iii

Table of Contents

Abstract...... ii Acknowledgements...... iii Table of Contents...... iv List of Tables...... vi List of Figures...... vii

Chapter One: Introduction...... 1 1.1 Project Motivation...... 1 1.2 Previous Work...... 1 1.3 Preliminary Outcrop Study – Chungo Member, Southern Alberta...... 2 1.4 Thesis Organization and Objectives...... 3 1.5 References...... 6

Chapter Two: Sedimentology and Sequence Stratigraphy of Shoreline Sheet Sand Bodies within an Epeiric Sea, Spirit River Formation, west-central Alberta...... 8 2.1 Introduction...... 8 2.2 Study Area and Methodology...... 9 2.3 Geological Setting...... 11 2.4 Basal Progradational Falher Facies...... 15 2.4.1 F0 – Massive mudstone...... 15 2.4.2 F1 – Massive sandstone with conglomerate...... 19 2.4.3 F2 – Interbedded marine mudstone and sandstone...... 19 2.4.4 F3 – Amalgamated hummocky cross-stratified sandstone...... 22 2.4.5 F4 – Swaley cross-stratified sandstone...... 23 2.4.6 F5 – Trough cross-stratified and parallel laminated sandstone and conglomerate.24 2.4.7 F6 – Interbedded sandstone, mudstone and coals...... 25 2.4.8 F7 – Finer grained coarsening upwards succession...... 25 2.4.9 F8 – Sandstone and organic mudstone...... 26 2.4.10 F9 – Thick fining upwards sandstone...... 27 2.4.11 Depositional Environment...... 27 2.5 Stratigraphic Framework...... 29 2.5.1 Stratigraphic Datum...... 29 2.5.2 Studied Succession Stratigraphic Architecture – Cross-Section B-B’...... 29 2.5.3 Falher N Facies Architecture – Cross-Section X-X’, Y-Y’, & Z-Z’...... 31

2.6 Discussion...... 34 2.6.1 Sheet Sand Body Facies Architecture and Geometric Characteristics in a Low Accommodation and Gradient Setting...... 34 2.6.2 Controls on Parasequence Set Stacking Pattern within an Active Foreland Clastic Wedge...... 37 2.7 Conclusions...... 40 2.8 References...... 42

Chapter Three: Reservoir Characterization of Tight ‘Wilrich’ Sandstone Reservoirs, Spirit River Formation, west-central Alberta...... 49 3.1 Introduction...... 49 3.2 Study Area and Methodology...... 49 3.3 Results...... 52 3.3.1 Grain Texture...... 52 3.3.2 Mineralogy and Provenance...... 54 3.3.3 Paragenetic Sequence...... 58 3.4 Discussion...... 61 3.4.1 Sequence Stratigraphy and Diagenetic Processes...... 61 3.4.2 Petrographic Responses...... 64 3.5 Conclusions...... 67 3.6 References...... 68

Chapter Four: Conclusions...... 72 4.1 Summary...... 72 4.2 Future Work...... 74 4.3 References...... 75

Appendix: Logged Cores...... 76

List of Tables

Table 2.1 – Summary of Facies...... 17

Table 3.1 – Summary of Grain Textures...... 52 Table 3.2 – Summary of Mineralogy...... 55

List of Figures

Figure 1.1 – Outcrop Analog Study Area and Measured Sections...... 4 Figure 1.2 – Chungo Member Selected Photos...... 5

Figure 2.1 – Study Area...... 10 Figure 2.2 – Transgressive Deposits and Major Marine-Flooding Surfaces...... 12 Figure 2.3 – Paleogeographic Maps of the Basal Falher and Middle Falher...... 13 Figure 2.4 – Stratigraphic Nomenclature Chart...... 14 Figure 2.5 – Regional Cross-Section...... 16 Figure 2.6 – Vertical Facies Succession with Gamma Ray and Core...... 18 Figure 2.7 – Selected Facies Photos...... 20 Figure 2.8 – Studied Succession Stratigraphic Architecture and Net Sandstone Maps...... 30 Figure 2.9 – Three Facies Architecture Cross-Sections, Portion of Net Sandstone Map, and Isopach Map, Falher N Parasequence Set...... 32 Figure 2.10 – Modern Subaqueous Profiles and Interpreted Paleo Basal Falher Subaqueous Profile...... 34 Figure 2.11 – Erosional Beds and Schematic Shoreline Progradation...... 35 Figure 2.12 – Cartoon of Storm Depositional Processes...... 37 Figure 2.13 – Schematic Cross-Section Illustrating Creation of Accommodation Space...... 39

Figure 3.1 – Study Area with ‘Wilrich’ Horizontal Wells and Production...... 50 Figure 3.2 – Methods from JMicroVision Software...... 51 Figure 3.3 – Grain Size Distribution within Shoreline Facies...... 53 Figure 3.4 – Thin Section Photos for Overview Grain Size and Mineralogy within Shoreline Facies...... 56 Figure 3.5 – Ternary Diagrams for Mineralogy and Provenance...... 57 Figure 3.6 – Paragenetic Sequence of Diagenetic Events...... 59 Figure 3.7 – Thin Section and Scanning Electron Images of Diagenetic Features...... 60 Figure 3.8 – Cross-Plot of Data Likely Related To Permeability...... 62 Figure 3.9 – Porosity Reduction Estimations...... 63 Figure 3.10 – Vertical Plots of Petrographic Data...... 65

vii

Chapter One: Introduction 1.1 Project Motivation

The basal progradational Falher, referred to as the ‘Wilrich’ by the petroleum industry, is an emerging unconventional liquid rich gas resource play within the Alberta Deep Basin. The ‘Wilrich’ low porosity-low permeability shoreline and fluvial sandstone reservoirs are gas charged, sealed by an updip water contact, forming a classic Deep Basin trap common within the Mesozoic sandstone intervals of the Alberta Deep Basin (Masters, 1979; Gies, 1984; Mas- ters, 1984). In the Alberta Deep Basin, mostly within Lower Cretaceous sandstone reservoirs, there is an estimated 1,750 Tcf of gas in place (Masters, 1984).

Recent advances in drilling and completion techniques of multi stage hydraulic fractured horizontal wells has allowed production from the previously uneconomic, tight (<0.1mD) ‘Wil- rich’ sandstone reservoirs, albeit with varying success. As of September 2016, over 530 horizontal wells have targeted the ‘Wilrich’ stratigraphic interval, resulting in over 795 Bcf of gas and 190 Mbbl of liquid condensate production.

1.2 Previous Work

Equivalent outcropping units in the west-central foothills of Alberta have previously been reported at Crescent Falls (Taylor and Walker, 1984, Rosenthal, 1988a), and the Cadomin area (MacDonald et al. 1988). Expansive overview studies across all of Alberta have generated paleogeographic maps and preliminary regional cross-sections of all the Lower Cretaceous stratigraphy including the basal Falher (Jackson, 1984; Smith et al., 1984; Cant, 1996). Detailed sedimentological and stratigraphic studies examining shoreline units and incised valleys provided the first detailed subsurface correlations of the prograding ‘Wilrich’ shorelines following the maximum transgression of the Moosebar Sea (Rosenthal, 1988b; Brownridge and Moslow, 1991). However, previous studies have failed to accurately portray the regional stratigraphic

1 framework for the basal Falher and related stratigraphy.

Within the Elmworth gas field, high reservoir quality zones of the middle and upper Fal- her parasequence sets have been described as lithology dependent. Grain-supported well sorted chert conglomerate beds exhibit the highest porosity and permeability due to the least damaging diagenetic effects, related to their higher chert content (Cant and Ethier, 1984). Recent studies on these middle and upper Falher parasequence sets focus on explaining the isolated linear trends of these highly economic, high quality reservoir zones, using sequence stratigraphy (Armitage et al., 2004; Caddel and Moslow, 2004; Nodwell and Hart, 2006), and paleobathyme-

try of underlying structural elements (Nodwell and Hart, 2006). The difference however, is the middle and upper Falher parasequence sets at Elmworth are more conglomerate prone reflective shorelines (Armitage et al., 2004; Zonneveld and Moslow, 2004), and the basal Falher parasequence sets studied herein are dominantly fine-grained dissipative shorelines, which require different techniques in order to identify greater reservoir quality rocks.

1.3 Preliminary Outcrop Study - Chungo Member, Southern Alberta

Exceptional outcrop exposures of wave-dominated sandstones shorelines of the Cam- panian Chungo Member are present within the fold and thrust belt in the foothills of southern Alberta, which were extensively studied in the 1980’s and 90’s (Rosenthal, 1984; McCrory and Walker, 1986; Rosenthal and Walker, 1987; Arnott, 1992; Cheel and Leckie, 1992). Outcropping shorelines of the Chungo Member are equivalent to the Milk River Formation in the subsurface of the southern Alberta and Saskatchewan plains (Leckie et al. 1994). Similar to shorelines of the Falher Member, the Chungo Member shorelines are east-west trending, and northward axially prograding, where they reached a progradational depositional limit extending across Alber- ta from Mount Yamnuska to the southern Saskatchewan border (Rosenthal and Walker, 1987; Leckie et al. 1994).

2 Crustal shortening has resulted in exposure of four complete stratigraphic sections within 5 km’s of each other, along Trap Creek and Highwood River (Fig. 1.1). Time was spent during the early phases of this thesis project studying sedimentology, ichnology, and stratigraphy of Chungo Member outcrops (Fig. 1.2). Detailed measurement of Chungo Member stratigraphic sections aided in confidently studying the very comparable facies of the basal Falher shoreline deposits in core, which do not offer the same broad view.

1.4 Thesis Organization and Objectives

This thesis is organized into two main chapters written as individual papers to be submitted for publication upon completion and review of this thesis, as well as an appendix that includes all core logged sheets. Chapter 2 is an investigation of facies distributions and stratigraphic architecture at a local scale (on the order of 10’s of km), as well as regional sequence stratigraphy of Bullhead and Fort St. John Group strata in the subsurface of west-central Alberta. Horizontal and vertical facies distributions are identified through core observations and- cor related using surrounding wells, with downhole well log suites, in a high density well dataset in order to construct various cross-sections and maps. Regional sequence stratigraphic correlations emphasizes parasequence set stacking patterns, and provides insight into possible basin and tectonic controls which could impact the A/S ratio at the shoreline. Chapter 3 is a petrophysical investigation relating thin section observations of mineralogy, grain texture, and diagenetic- fea tures, to geophysical well log responses and lab measured data. This comparison evaluates the mineralogy, grain textures, and diagenetic control on permeability.

From a practical outcome perspective, Chapter 2 emphasizes ‘non-textbook’, and unique sedimentological and sequence stratigraphic characteristics of progradational sheet sand bodies within an epeiric sea, and Chapter 3 provides insight for determination of ‘sweet spots’ within such continuous sheet sand bodies.

3 N Highwood River 3 Alberta Saskatchewan British Columbia Highwood River 2 Thrust sheet (teeth indicate dip direction; deﬁned, approximate)

Calgary Outcrop location 200 km

U.S.A Highwood River 1 Thrust sheet locations from Lebel and Trap Creek Kisilevsky, 2000

Lithology Sedimentary Structures non-marine trough cross-stratification 1 km sandstones matrix supported swaley cross-stratification conglomerate hummocky cross-stratification Highwood River 2 Highwood River 3 nearshore marine wave ripple lamination 80m sandstones loading structures NE marine sandstones Diplocraterion 76m Ophiomorpha marine siltstones Planolities and mudstones Rhizocorallium Thalassinoides Incised 70m 70m Highwood River 1 Channel? Wave-Dominated 66.5m Middle and Lower Shoreface

Non-marine SW 60m 60m 60m Oﬀshore Transition Trap Creek

55.5m

50m 50m 50m 50m Wave-Dominated Upper Shoreface

40m 40m 40m 40m

Wave-Dominated Middle and Lower Shoreface

30m 30m 30m 30m

20m 20m 20m 20m

Oﬀshore Transition

10m 10m 10m 10m

Oﬀshore

0m 0m 0m 0m Top Colorado Group F F F F P VF M C P P VF M C VF M C P VF M C VC VC VC VC Gr Gr Gr Mud Mud Mud Mud Gr Silt Silt Silt Silt Sand Gravel 1.06 km Sand Gravel 1.95 km Sand Gravel 1.24 km Sand Gravel

Figure 1.1 - Map of outcrop locations along Trap Creek and Highwood River with measure sections and stratigraphic interpretation (Map data: Google, DigitalGlobe). Highwood River outcrop 1 and 2 numbers are reversed compared to Rosenthal and Walker, 1987.

4 A B

Oﬀshore transition Wave-dominated shoreface

Oﬀshore

C D

E F

G H

Marine conglomerates

Non-marine

Figure 1.2 - Selected outcrop photos of stratigraphic sections, sedimentary structures, ichnology, and stratigraphic surfaces: A) Near complete Highwood River 2 outcrop section; B) High angle trough cross-stratification beds; C) Internal structure of a trough cross-stratified 3D dune; D)Low angle swaley cross-stratification with scattered pebbles; E) Meter-scale view of swaley cross-stratification; F)hummocky cross-stratified bed with erosional scoured base and wave rippled top; G) Transgressive surface of marine erosion with marine conglomerates overlying non-marine sandstones; H) Ophiomorpha bioturbated sandstone bed.

5 1.5 References Armitage, I.A., Pemberton S.G., and Moslow, T.F., 2004, Facies succession, stratigraphic occurrence, and paleogeographic context of conglomeratic shorelines within the Falher “C”, Spirit River Formation, Deep Basin, west-central Alberta: Bulletin of Canadian Petroleum Geology, v. 52, no. 1, p. 39-56. Arnott, R.W.C., 1992, Ripple cross-stratification in swaley-cross stratified sandstones of the Chungo Member, Mount Yamnuska, Alberta: Canadian Journal of Earth Sciences, v. 29, p. 1802- 1805. Brownridge, S. and Moslow, T.F., 1991, Tidal estuary and marine facies of the Glauconite Mem- ber, Drayton Valley, central Alberta, in Smith, D.G., Reinson, G.E., Zaitlin, B.A., and Rahmani, R.A., eds., Clastic Tidal Sedimentology: Canadian Society of Petroleum Geologists Memoir 16, p. 107-122. Caddel, E.M. and Moslow, T.F., 2004, Sedimentology and stratal architecture of the Falher C Member, Spirit River Formation, from outcrop on Bullmoose Mountain, northeastern British Columbia: Bulletin of Canadian Petroleum Geology, v. 52, no. 1, p. 4-22. Cant, D.J., 1996, Sedimentological and sequence stratigraphic organization of foreland clastic wedge, Mannville Group, Western Canada Basin: Journal of Sedimentary Research, v. 66, p. 1137-1147. Cant, D.J., and Ethier, V.G., 1984, Lithology-dependent diagenetic control of reservoir properties of conglomerates, Falher Member, Elmworth Field, Alberta: AAPG Bulletin, v. 68, p. 1044-1054. Cheel, R.J., and Leckie, D.A., 1992, Coarse-grained storm beds of the Upper Cretaceous Chungo Member (Wapiabi Formation), southern Alberta, Canada: Journal of Sedimentary Petrology, v. 62, p. 933-945. Gies, R.M., 1984, Case history for a major Alberta Deep Basin gas trap: the Cadomin Formation, in Master, J.A., ed., Elmworth – Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 115-140. Jackson, P.C., 1984, Paleogeography of the Lower Cretaceous Mannville Group of western Cana- da, in Masters, J.A., ed., Elmworth: Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 49-77. Leckie, D.A., Bhattacharya, J.P., Bloch, J., Gilboy, C.F., and Norris, B., 1994, Cretaceous Colorado / Alberta Group of the Western Canada Sedimentary Basin, in Mossop, G., and Shetsen, I., complilers., eds., Geological Atlas of the Western Canadian Sedimentary Basin: Canadian Society of Petroleum Geologists and Alberta Research Council, p. 335-352. Lebel, D., and Kisilevsky, D., 2000, Preliminary geology, Turner Valley (82J/9): Geological Survey of Canada, Open File 3875, scale 1:50 000. Masters, J.A., 1979, Deep Basin gas trap, western Canada: AAPG Bulletin, v. 63, p. 152-181.

6 Masters, J.A., 1984, Lower Cretaceous oil and gas in western Canada, in Master, J.A., ed., El- mworth – Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 1-34. MacDonald, D.E., Langenberg, C.W., and Strobl, R.S., 1988, Cyclic marine sedimentation in the Lower Cretaceous Luscar Group and Spirit River Formation of the Alberta Foothills and Deep Ba- sin, in James, D.P., and Leckie, D.A., eds., Sequences, Stratigraphy, Sedimentology: Surface and Subsurface: Canadian Society of Petroleum Geologists Memoir 15, p. 143-154. McCrory, V.L., and Walker, R.G., A storm and tidally-influenced prograding shoreline-Upper Cre- taceous Milk River Formation of southern Alberta, Canada: Sedimentology, v. 33, p. 47-60. Nodwell, B.J., and Hart, B.S., 2006, Deeply-rooted paleobathymetric control on the deposition of the Falher F conglomerate trend, Wapiti field, Deep Basin, Alberta: Bulletin of Canadian Petro- leum Geology, v. 54, p. 1-21. Rosenthal, L., 1984, The stratigraphy, sedimentology and petrology of the Upper Cretaceous Wapiabi and Belly River formations in southwestern Alberta: PhD thesis, McMaster University, Hamilton, Ontario, Canada, 250 p. Rosenthal, L., 1988a, Stratigraphy and depositional facies, Lower Cretaceous Blairmore-Luscar Groups, central Alberta foothills: Canadian Society of Petroleum Geologists, Field trip guide, 55p. Rosenthal, L., 1988b, Wave dominated shorelines and incised channel trends: Lower Cretaceous Glauconite Formation, west-central Alberta, in James, D.P., and Leckie, D.A., eds., Sequences, Stratigraphy, Sedimentology: Surface and Subsurface: Canadian Society of Petroleum Geologists, Memoir 15, p. 207-220. Rosenthal, L., and Walker, R.G., 1987, Lateral and vertical facies sequences in the Upper Creta- ceous Chungo Member, Wapiabi Formation, southern Alberta: Canadian Journal of Earth Scienc- es, v. 24, p. 771-783. Smith, D.G., Zorn, C.E., and Sneider, R.M., 1984, The paleogeography of the Lower Cretaceous of western Alberta and northeastern British Columbia in and adjacent to the Deep Basin of the Elmworth area, in Masters, J.A., ed., Elmworth: Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 79-114. Taylor, D.R., and Walker, R.G., 1984, Depositional environments and paleogeography in the Albi- an Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines formations, Alberta: Canadian Journal of Earth Sciences, v. 21, p. 698-714. Zonneveld, J.-P., and Moslow, T.F., 2004, Exploration potential of the Falher G shoreface conglomerate trend: evidence from outcrop: Bulletin of Canadian Petroleum Geology, v. 52, no. 1, p. 23-38.

7 Chapter Two: Sedimentology and Sequence Stratigraphy of Shoreline Sheet Sand Bodies within an Epeiric Sea, ‘Wilrich’, Spirit River Formation, west-central Alberta.

2.1 Introduction

The principle objective of this thesis project was to map and evaluate reservoir properties of the ‘Wilrich’. The stratigraphic interval is under studied as it was of minor industry interest until recently. In order to achieve this goal, for this chapter sedimentary facies and their horizontal and vertical distributions were studied. As well, sequence stratigraphic as opposed to lithostratigraphic correlations was used to establish a subsurface sequence stratigraphic framework for the studied succession.

Progradational wave-dominated shoreline successions typically display a gradational transition from the offshore environment below storm wave base, to offshore transition which is situated between storm wave and fair weather wave base, to the shoreface itself above fair-weather wave base (Rosenthal and Walker, 1987; Walker and Plint, 1992; Reading and Collinson, 1996; Clifton, 2006). An example of such a shoreline was observed in outcrops of the Chungo Member along Highwood River (Fig.1.2A). However, progradational shoreline models were establish where water depth was sufficiently accommodating for the given wave base, i.e. water depth is greater than wave base. Within the Western Canadian Foreland Basin for much of the Early Cretaceous, a shallow epeiric sea has been interpreted (Cant, 1984; Cheel and Leckie, 1990; Varban and Plint, 2005), leading to implications for sedimentology and stratigraphy of progradational shorelines where wave base is greater than water depth. Firstly, the effect of shallow paleo water depth and thereby wave energy, of strongly progradational shorelines with low angle gradients, and their resultant deposits by mapping horizontal and vertical facies distributions using a high density subsurface well database is investigated.

Sequence stratigraphy was first pioneered using 2D seismic lines, where sequence stratigraphic surfaces, systems tracts, and sequences were identified and relative-sea level curves

8 established (Vail et al. 1977; Vail, 1987; Van Wagoner et al. 1990). Recently a focus has been shifted towards methodology over model, by using the observations of stratal stacking patterns in the rock record, as well as the importance of local basin controlling factors which influence accommodation and sediment supply at the shoreline (Catuneanu et al., 2011). Secondly, the controls for drastically different parasequence set stacking patterns within the Upper Mannville clastic wedge within the active Alberta foreland basin is investigated.

2.2 Study Area and Methodology

The 140 by 160 km study area is located in west-central Alberta within the Alberta Deep Basin on the eastern side of the deformation belt spanning T46 to T58 and R13 W5 to R1 W6 (Fig. 2.1). Within the study area 1,469 well penetrations with associated downhole log suites were used for correlations, together with 26 cores intersecting the interval of interest. Each core was logged in detail for physical sedimentary structures, trace fossil assemblages, lithology and grain size for description of facies, as well as the identification of sequence stratigraphic surfaces. Sequence stratigraphic surfaces and facies were calibrated to well log responses in order to correlate between the large number of wells where core data is unavailable. Resistivity and gamma ray logs were most useful for correlating flooding surfaces. The detailed sequence stratigraphic correlations are facilitated by the large number of available geophysical well logs penetrating the stratigraphic interval, together with the sedimentary facies observed in cores.

A typical suite of geophysical well logs, distinctly in the gamma ray log profile, display a single 10-25 m thick coarsening upwards trend of the shoreline sandstone interval. However, cores show these to be comprised of stacked, 1 to 2, shallowing upwards trends within the single overall shallowing upwards trend observed on well logs. The individual shallowing upwards trends, as seen in core, are defined as parasequences, the fundamental building blocks for sequence stratigraphy (Van Wagoner et al. 1988; Van Wagoner et al. 1990). However, limitations

9 T59 Alberta N Saskatchewan

British Columbia T56

Study Area Edmonton B’ Z’ T53 Y’ X’ Calgary Deformed Belt T50 Z U.S.A Y 200 km to 0.6 to 1560.2 X Gas Cnd BOE Ratio - 10 : 1 Multiplier - 4x B T46 R1 W6 R26 R24 R22 R20 R18 R16 R13 W5 Core control Cross section reference 20 km Well control Other cross sections created

Figure 2.1 - Map of study area within Alberta Deep Basin, Canada. Wells and core locations examined in this study are denoted by small and large grey circles respectively. in numbers of core within the study area do not allow for a high confidence in the mapping of individual parasequences. The major marine-flooding surfaces (mFS), bounding the stacked, overall coarsening upwards shoreline deposits bounding parasequence sets (Van Wagoner et al. 1988; Van Wagoner et al. 1990), are identifiable and mappable on well logs throughout the study area, and are used to delineate the stratigraphic architecture. Similarly, middle and upper Falher members have been subdivided into both parasequence sets and parasequences in previous subsurface and outcrop studies (Arnott, 1993; Casas and Walker, 1997; Rouble and Walker, 1997; Armitage et al., 2004; Zonneveld and Moslow, 2004; Nodwell and Hart, 2006).

Marine flooding surfaces are defined as the surface representing an increase in water depth, or deepening event (Van Wagoner et al., 1988; Bhattacharya, 1993). Herein the term major marine-flooding surface (mFS) is used as the regional correlatable surface separating parasequence sets, with a change to deeper water deposits, equivalent to allomembers of Bhattacha-

10 rya and Walker (1991). Major marine-flooding surfaces can unconformably overlie either marine strata of F2, F3, F4, F5 or non-marine strata of F6. Surfaces which represent an increase in water depth as well, but were observed in distal areas and have a smaller lateral mappable extent, but likely have a correlative surface within the thick shoreline sandstone intervals, are termed as marine-flooding surfaces (FS) and bound parasequences (Van Wagoner et al. 1988; Van Wagon- er et al. 1990).

In wells without core control major flooding surfaces are picked at the base of relatively thick mudstone overlying sandstone based on the gamma ray log; resistivity and neutron density logs typically show a characteristic sharp kick left (Fig. 2.2).However, core examples show two examples of the transgressive surface of marine erosion (TSE) demarcated by angular mud rip up clasts from wave ravinement (Fig. 2.2A) and a conglomeratic transgressive lag (Fig. 2.2B). The TSE is overlain by up to 2 m of heterolithic and bioturbated deposits or fining upwards conglomerate intervals and sandstone to silty mudstone successions. In wells with no core, these transgressive deposits cannot be confidently distinguished from the regressive deposits. Thus, for consistency the major marine-flooding surface is picked on well logs at the base of the thick mudstone succession. The thickness of sandstone and conglomerate between the transgressive surface of marine erosion, and major marine-flooding surface, varies between 0.3 to 2 m. Thus, the error is minor in relation to the more than commonly 15 m thick parasequence sets throughout this study area.

2.3 Geological Setting

The Early Albian Spirit River Formation clastic wedge was deposited within the Alberta foreland basin which had asymmetric east-west trough geometry (Cant and Stockmal, 1989). During this time period eustatic sea level curves show an overall rise (Kauffman, 1977; Vail et al., 1977; Haq et al., 1988; Miller et al., 2005). However, it should be noted that induced flexural

11 A) 01-21-051-17 W5 Neutron Porosity (%) Unit (m) GR (API) Density Porosity (ss) (%) Deep Resistivity (OHM*M) Depth Depth

Stratigraphic Stratigraphic 0 150 45 30 15 0 -15 1 10 100 1000 undiﬀerentiated 2640 Upper Mannville Falher L Falher 2650 mFS TSE

TSE 2660 Falher M Falher

2670 mFS

mFS N Falher 2680 FS

Neutron Porosity (%) Unit B) 05-17-049-18 W5 (m) GR (API) Density Porosity (ss) (%) Deep Resistivity (OHM*M) Depth Depth

Stratigraphic Stratigraphic 0 150 45 30 15 0 -15 1 10 100 1000

3180 undiﬀerentiated Upper Mannville Upper Mannville mFS

3190 Falher L Falher mFS TSE TSE 3200

3210 Falher N Falher

3220 mFS

Figure 2.2 - Transgressive successions from core intervals showing the transgressive surface of marine erosion surface (TSE) with major marine flooding surface (mFS) ‘pick’ shown on well logs. A) 01-21-051-17 W5, 2649.39 to 2652.24 m and B) 05-17-049-18 W5, 3192.00 to 3194.76 m. subsidence plays an important role in overprinting the effects of eustatic sea level within the active Alberta foreland basin (Caldwell, 1984; Stott, 1984; Leckie, 1986). The Spirit River Forma- tion clastic wedge form a third-order, overall progradational to aggradational, depositional cycle comprised of marine conglomerate, sandstone and mudstone beds and non-marine deposits (Leckie, 1986). The formation consists of higher frequency depositional cycles with approxi-

12 mately west-east orientated, northward prograding shorelines along the axis of the basin (Fig. 2.3) (Cant, 1984; Jackson, 1984; Leckie, 1986). Stratigraphic nomenclature for this study area and the equivalent deposits of the Peace River plains, central Alberta plains and central foothills is shown in Figure 2.4. Nomenclature for the Spirit River Formation was first described in type wells by the Alberta Study Group (1954), with the Falher Member having more than 60% very fine- to fine-grained sandstone and the Wilrich Member defined as a dominantly shaley succession occurring seaward.

In this subsurface sequence stratigraphic study, parasequence sets are informally assigned Falher unit names. Each Falher unit consists of offshore mudstone deposits of the Wilrich Member, shoreline deposits of the Falher Member, and non-marine deposits of the undifferentiated Upper Mannville as these three lithostratigraphic units are genetically related and time correlative. This stratigraphic nomenclature build on Cant (1984), within the Peace River Plains

A) B)

SASK. B. C. B. C. SASK. ALBERTA ALBERTA EROSIANAL EROSIANAL EDGE OF EDGE OF MANNVILLE MANNVILLE

CLEARWATER SEA

CLEARWATER SEA SIXTH MERIDIAN SIXTH MERIDIAN FIFTH MERIDIAN

OPEN MARINE FIFTH MERIDIAN OPEN MARINE

EDGE OF EDGE OF DISTURBED DISTURBED BELT BELT SHELF SANDS, OFFSHORE BARS SHELF SANDS, OFFSHORE BARS BEACH, BARRIER ISLAND BARRIER ISLAND

BEACH EDMONTON EDMONTON N N CONTINENTAL PLAIN Marine mudstones Marine mudstones CONTINENTAL Shelf sands, oﬀshore bars PLAIN Shelf sands, oﬀshore bars

Beach, barrier island, CALGARY CALGARY Study Area Beach, barrier island, Study Area bar sands > 10 m bar sands > 10 m

Continental Fluvial system Continental Fluvial system

200 km 200 km

Figure 2.3 - Paleogeographic maps of A) basal progradational Falher, Falher H and equivalents and B) Middle Falher (C, D, E, and F cycles) and equivalents. Modified from Jackson (1984). Study area is outlined with blue box.

13 13-17-054-20 W5

Gamma Ray Sonic Stratigraphic

(API) (m) (UB/M)

Unit Depth B) 0 75 150 500 400 300 200 100

A) Central Peace River Central This Study Viking Fm Colorado Gp Colorado Joli Fou Foothills Plains Alberta Plains 2750

X X Base Fish Scales X X X X Base Fish Scales X X Blackstone Shaftesbury

Paddy Viking Viking Fm 2800 Joli Fou Joli Fou Fm ? Basal Colorado ? Upper Mannville Undiﬀerentiated Upper Mannville Spirit River Fm Spirit River 2850

Albian Cadotte Fort St. John Gp Fort Harmon Peace River Fm River Peace Mountain St. John Gp Fort Upper Park Mannville Notikewin Upper Grande (undiﬀ) Falher Mannville

Cache 2900

Gates Fm Gates (undiﬀ) Torrens Falher Mb Wilrich Fm Spirit River Glauconitic Spirit River Fm Spirit River Fort St. John Gp Fort

Lower Cretaceous Lower Wilrich Mb

Moosebar K Falher Sandstone mFS 4 Bluesky Ostracod Beds Bluesky Luscar Gp Luscar

Fm L Falher mFS 3

Calcareous Mbr 2950 Upper M Mannville Gp Mannville Falher Falher Gething Lower Gething Fm

Gladstone Mb Aptian

Wilrich MxFS Fm Bullhead Gp Bullhead Bullhead Gp Bullhead Bluesky Ellerslie Fm Ellerslie 3000 Cadomin Cadomin Cadomin Fm Gething Fm Gething Barremian Bullhead Gp Figure 2.4 - A) Stratigraphic nomenclature chart for study area and 3050 adjacent regions, modified from Hayes et al. (1994). B) Type well of Lower Cretaceous deposits within the study area. 3100 Cadomin Fm eight transgressive-regressive shoreline sedimentary sequences within the Spirit River Forma- tion, including the Falher A through E. More recent studies further to the south documented geologically older Falher shorelines, in subsurface the Falher F (Nodwell and Hart, 2006) and in outcrop the Falher G through K (Zonneveld and Moslow, 2004). The younger Falher shoreline units, A through G, are referenced to as the middle and upper Falher parasequence sets in this study. Based on detailed correlations within the study area and regional correlations, at least

14 five parasequence sets are located between the Hoadley Barrier in the south and the subsurface equivalent of the Falher G parasequence set of Zonneveld and Moslow (2004) (Fig. 2.5). In this study, the oldest Falher parasequence sets start after the shift from the retrogradational stacking pattern of the Bluesky Formation, to a strongly progradational stacking pattern above the geometric maximum flooding surface. At the Hoadley Barrier, the maximum flooding surface separates shoreline sandstone into a lower and upper unit, demarcating the southernmost and most landward shoreline. Within this study, the basal progradational Falher parasequence sets are informally named from oldest to youngest, starting with Falher O. The subsequent younger paleo seaward parasequence sets are named Falher N through Falher K (Fig. 2.5), with an unknown number of parasequence sets located between the northern end of this study area and the southern limit of Falher G of Zonneveld and Moslow (2004). Note that additional marine shoreline parasequence sets, shown as coarsening upwards trends on well logs, also exists between the southern portion of this study area and the Hoadley Barrier further to the south and are grouped together and informally named as Falher P. Further studies are required to map and formally assign a Falher unit name to all the parasequence sets within the Spirit River Formation.

2.4 Basal Progradational Falher Facies

Previous studies have described and discussed the sedimentary facies and facies associations of the Falher Member (e.g. Leckie and Walker, 1982; Leckie, 1983; Arnott, 1993; Casas and Walker, 1997; Rouble and Walker, 1997; Armitage et al., 2004; Caddel and Moslow, 2004; Zonne- veld and Moslow, 2004; DesRoches, 2008). In this study, similar sedimentary facies were documented in cores within the study area. Ten facies are summarized in Table 2.1, largely shown in a vertical succession in Figure 2.6, and described in greater detail in the following sections.

2.4.1 F0– Massive mudstone

Facies 0 is mainly composed of mudstone to silty mudstone with thin mm to cm scale

15 64.8 km 54.2 km 41.5 km 17.2 km 23.5 km 44.0 km 41.7 km 74.2 km 46.6km 18.6km 27.0km

12-15-042-04 W5 06-30-043-10 W5 10-02-047-15 W5 05-17-049-18 W5 16-03-051-18 W506-23-052-20 W5 01-35-055-23 W5 07-21-058-26 W5 11-11-062-06 W6 13-27-065-09 W6 06-15-067-10 W6 10-01-070-11 W6 GR S GR S GR S GR S GR S GR S GR S GR S GR S GR S GR S GR S A’ A Datum - Top Mannville Notikewin Upper Mannville undiﬀerentiated Upper Mannville Falher A undiﬀerentiated Medicine River Coal Falher B Studied Falher C Hoadley Barrier Succession Glauconite_B Falher P Falher D Falher O Falher L Falher F Falher N Falher M Falher K Falher E mFS 0 Falher G to J Glauconite_B mFS 2 Wilrich mFS 1 mFS 3 mFS 4 mFS 5 Wilrich Falher G to J

Gething Wilrich

Saskatchewan pre-Cretaceous N Unconformity Gething Bluesky Alberta Cadomin

British Columbia Approximate 100 m extent of Peace River Arch pre-Cretaceous Unconformity A’ Study 100 km Area Edmonton Hoadley Cadomin Fm Falher parasequence set sandstones A Barrier Gething Fm Wilrich marine mudstones Spirit River Formation Calgary Bluesky/Glauconite Fm Coal horizon relative-sea level curve

Upper Mannville Major ﬂooding surfaces undiﬀerentiated U.S.A Middle and 200 km Upper Falher

Figure 2.5 - Regional Fort St. John and Bullhead groups Basal Falher cross-section extending in the south from the Hoadley Barrier, to the north and previously defined parasequence sets of the ?

Falher Member. 10-01-070-11 W6 well is type log for overly- Time ing middle and upper Falher parasequence sets in the Elm-

16 worth Field. Studied succession is outlined with blue box. Biogenic Depositional Facies Lithology & Grain Size Physical Sedimentary Stuctures Sedimentary Environment Stuctures

Mudstone, silty mudstone, Massive to planar laminated mudstones, mm to Plan., Phyc., F0 very fine-sandstone interbeds cm scale silt- and sandstone interbeds; starved Pal., M.S. current ripples, normal and inverse graded beds. Transgressive Very fine- to fine-grained Cr.B. Shoreline Low angle parallel to converging laminations, F1 sandstone, pebbly sandstone, matrix & clast supported normally graded trend. conglomerate Massive to planar laminated mudstone, mm to cm Plan., Phyc., Interbedded mudstone to scale silt- and sandstone interbeds; starved current Thal., Chon., Offshore silty mudstone, with siltstone ripples, normal and inverse graded beds, wave M.S., He., F2 and very fine-grained reworked ripples with mud drapes and soft Astr., Aren., Transition sandstone beds sediment deformation. Thicker 5 to 40 cm Cyln., Cos., sandstone beds are hummocky cross stratified. Zoo. Amalgamated or wave or combined flow ripple Cr.B., Pal., Storm-Dominated Very fine-grained sandstone, capped hummocky cross stratified sandstone Teich., Cyln., F3 Lower Shoreface mudstone interbeds beds. Small angular and rounded mudstone rip up Oph., Dip., clasts, carbonaceous debris. Astr.

Pal., Oph., Very fine- to fine-grained Swaley cross-stratified sandstones. Structureless Wave- & sandstone. Scattered pebbles on bed boundaries Fu., Rhiz., sandstone, granule to pebbly Storm-Dominated F4 and laminations. Cylin. sandstone Middle Shoreface

Fine- to medium-grained sandstone, granule to pebbly High angle laminations, trough cross stratiﬁcation, Cr.B., Mac., Wave-Dominated F5 sandstone, matrix & clast current ripples and low angle planar bedding. Fu., R.T. Upper Shoreface & supported pebble Foreshore conglomerate

Coal, mudstone to silty Trough-cross stratification, current and climbing No trace Non-Marine F6 mudstone, very fine- to ripples, angular to sub-round mud rip-up clasts. fossils Coastal Plain & medium-grained sandstone observed Fluvial Channel Silt- and sandstone interbeds consist of mm scale Muddy siltstone to siltstone, Plan., Phyc., Low Gradient, normal graded beds, and starved current ripples. F7 very fine- to fine-grained Teich., Astr. Dissipative Sandstones show horizontal to wavy laminations sandstone intercalated with current ripple laminations. Shoreline Mudstone intervals are massive to wavy Plan., Cr. B., Interdistributary Very dark and light grey laminated, thin (mm) scale sandstone intervals Ross., U.B., Bay, Distributary F8 mudstone, very fine- to contain starved current ripples. Sandstones Gyr., Dip. fine-grained sandstone display current ripple, and horizontal to wavy Channel & Lagoon laminations and trough cross-stratification. Cr.B. F9 Fine-grained sandstone Trough-cross stratification, wavy laminations, Incised Channel carbonaceous debris.

Table 2.1 - Table of facies in basal progradational Falher parasequence sets within study area. Ich- nogenera abbreviations: Aren: Arenicolites, Astr: Asterosoma, Chon: Chondrites, Cos: Cosmorhaphe, Cr.B.: cryptic bioturbation, Cyln: Cylindrichnus, Dip: Diplocraterion, Fu: Fugichnia, Gyr: Gyrolithes, He: Helminthopsis, Mac: Macaronichnus, M.S: mantle and swirl structure, Oph: Ophiomorpha, Pal: Palaeophycus, Phyc: Phycosiphon, Plan: Planolites, Rhiz: Rhizocorallium, R.T.: root traces, Ross: Rosselia, Teich: Teichichnus, Thal: Thalassinoides, Zoo: Zoophycos. Trace fossils listed in decreasing abundance.

17 Top A 2654.99 m

Depth (m) Gamma Ray Stratigraphic & Strat. Facies Unit (API) Surface 0 75 150

M. F6 Up. F0 F7 F3 F4 2650 m Falher L Falher mFS 3 F0 F5

F5 A F4

2660 m F4 Falher M Falher F3 Bottom mFS 2 F0 2668.83 m

Spirit River Formation Spirit River 2670 m F4

F3 F0 Top

Falher N Falher mnFS 2680 m F3 B 2684.32 m F2 F0 mnFS B F3 mFS 1 2690 m F2 F3 Wilrich F2 F0 Fm Bluesky

Figure 2.6 - Gamma ray log and selected core from well 01-21-051-17 W5 showing vertical facies relationships; each core sleeve is 75 cm and Bottom core is 8.9 cm in diameter. 2696.10 m 18 very fine- to fine-grained sandstone. Mudstone intervals are massive to planar laminated. Thin mm to cm scale silt- and sandstone interbeds contain common starved current ripples and normally graded beds (Fig. 2.7A & 2.7B). Planolites and mantle and swirl structures occur in mudstone beds, while Phycosiphon and Palaeophycus are present within siltstone and sandstone beds. F0 pinches out landward from 3 to 0 m.

F0 has the lowest sandstone content of the 10 identified facies, commonly less than 30 %. F0 is interpreted to represent the preserved transgressive deposits, with the mud richness a result of sandy sediment being trapped in coastal plain areas during shoreline retreat (Cattaneo

and Steel, 2003).

2.4.2 F1 – Massive sandstone with conglomerate

Facies 1 is composed of very fine- to fine-grained sandstone and clast and matrix supported conglomerate with a sandy matrix. Sandstone beds contain low angle to converging laminations, resembling swaley or amalgamated hummocky cross-stratification. No trace fossils were observed, however cryptic bioturbation was present within sandstone beds. Deposits of F1 show an overall fining upward trend, with conglomerate occurring at the base and pebbles decreasing in abundance within fining upwards sandstone.

F1 differs from deposits of F0 in lithology and stratigraphic occurrence. Deposits of F0 unconformably overlie deposits of F2, F3, F4, F5 and F6 both in distal and proximal areas. How- ever, F1 deposits only unconformably overlie F5 and F6 in more proximal areas. The conglomeratic lags are a concentrated bed reflecting erosion of the underlying shoreline, whereby wave reworking processes winnowed finer grains leaving behind coarser pebbles (Van Wagoner et al., 1990; Cattaneo and Steel, 2003). F1 can also transition upwards into F0 deposits.

2.4.3 F2 - Interbedded marine mudstone and sandstone

Facies 2 is composed of mudstone to silty mudstone interbedded with siltstone to very fine-grained sandstone. Mudstone intervals are massive to planar laminated. Thin mm to cm

19 A 4 cm C D 4 cm Ph Ch

P P Th E B 4 cm F

4 cm 4 cm 4 cm

G I J 4 cm

Pa Pa

4 cm H

3 cm 3 cm

K M O

3 cm P 3 cm 3 cm L N Ma Rt

Ma Rt

4 cm 3 cm 4 cm

20 Q 4 cm S 4 cm V 4 cm

T 3 cm R

U 4 cm

UB P 4 cm Figure 2.7 - A) F1: planar laminated mudstone, with normally graded sandstone beds and mi- nor bioturbation (16-03-051-18 W5, 2790.9 m); B) F1: planar laminated mudstone with starved current ripples (01-21-051-17 W5, 2667.6 m); C) F2: hummocky cross-stratified bed, interbedded with planar laminated mudstone beds (01-21-051-17 W5, 2683.2 m); D) F2: diversely bioturbated silty mudstone interval (16-03-051-18 W5, 2792.0m); E) F2: current ripple lamination with mudstone drape (01-21-051-17 W5, 2688.7 m); F) F3: rounded mudstone rip clasts within low angle planar stratified very fine-grained sandstone (16-03-051-18 W5, 2786.8 m); G) F3: wave-rippled hummocky-cross stratified bed with Palaeophycus burrows (02-25-054-21 W5, 2921.5 m); H) F4: Scattered chert pebbles within fine-grained sandstone (13-34-046-16 W5, 3263.7 m); I) F4: lower fine-grained sandstone with low angle swaley cross -stratification (05-17-049-18 W5, 3217.5 m); J) F5: upper fine-grained chert pebble cross trough-stratified sandstone (01-35-055-23 W5, 3024.2 m); K) F4: cryptically bioturbated fine-grained sandstone (13-34-046-16 W5, 3265.2 m); L) F5: Macaronichnus segregatis burrows (16-03-051-18 W5, 2778.1 m); M) F5: poorly sorted chert pebble conglomerate at base of fining upward, rip current channel (13-29-046-15 W5, 3156.1 m); N) F5: root traces (01-25-055-26 W5, 3478.3 m); O) F6: ashy coal (01-28-048-18 W5, 3216.1 m); P) F6: large angular mudstone rip up clasts (14-20-050-21 W5, 3375.8 m); Q) F7: current ripple lamination intercalated with carbonaceous laminations (01-21-051-17 W5, 2643.8 m); R) mm to cm scale silty normal graded beds (16-03-051-18 W5, 2771.7 m); S) current ripple laminations (14-18-054-22 W5, 3027.2 m); T) starved current ripples, lenticular bedding (02-16-050-20 W5); U) bioturbation within dark mudstone (14-18-054-22 W5, 3029.1 m); V) trough cross-stratification (10-26-053-16 W5, 2384.5 m). scale silt- and sandstone interbeds contain common starved current ripples and normally and inverse graded sand- to siltstone beds, with some wave reworked ripples with mud drapes and rare soft-sediment deformation structures (Fig. 2.7E). Thicker 5 to 40 cm very fine-grained sandstone beds are planar laminated to hummocky cross stratified that occasionally have wave rippled tops (Fig. 2.7C). Trace fossils, in decreasing abundance within mudstone beds, include Planolites, Thalassinoides, Chondrites and mantle and swirl structures. Trace fossils, in de-

21 creasing abundance within siltstone and sandstone beds, include Phycosiphon, Helminthopsis, Thalassinoides, Asterosoma, Arenicolites, Cylindrichnus, Cosmorhaphe and Zoophycos. F2 ranges in thickness from 2 to 15 m.

Sandstone beds displaying low angle planar to rare converging laminations with basal erosional scoured bases and occasionally capped by wave ripples, then overlain by mudstone, are interpreted as hummocky cross-stratified storm beds (Leckie and Walker, 1982). Mudstone intervals lacking internal lamination or bioturbation likely represent fluid mud deposition, most likely a result of storm waves re-suspending mud (Ichaso and Dalyrmple, 2009). Starved current ripples represent wave induced unidirectional currents and normally and inverse graded beds are interpreted as storm-induced hyperpycnites (Bhattacharya and MacEachern, 2009). Heav- ily bioturbated mudstone intervals reflect fair-weather conditions between storms (Rosenthal and Walker, 1987). F2 is interpreted to have been deposited above storm wave base and below fair weather wave base, in an offshore transition depositional environment (Leckie and Walker, 1982; Rosenthal and Walker, 1987; MacEachern and Pemberton, 1992).

2.4.4 F3 –Amalgamated hummocky cross-stratified sandstone

Facies 3 ranges in thickness from 2 to 7 m and is dominantly composed of lower to upper very fine-grained sandstone with minor mudstone and silty mudstone beds. Internally beds display low angle planar and rarer converging laminae. Beds are commonly capped by wave or combined flow ripples (Fig. 2.7G). Bases are commonly low relief erosional surfaces, which commonly erode the underlying bed. Bed and bed sets thickness ranges from 5 to 110 cm. F3 is interpreted to be dominantly comprised of amalgamated hummocky cross-stratification. Small, < 2 cm, angular to rounded mudstone rip up clasts (Fig. 2.7F) and carbonaceous debris are locally present. In places sandstone beds vertically grade into silty mudstone. Trace fossils, in sandstone beds include Palaeophycus, Teichichnus, Cylindrichnus, Ophiomorpha, Diplocraterion and Asterosoma.

Low angle planar laminae that show converging laminae are interpreted as amalgamated

22 hummocky cross-stratification, generally considered to be formed during storms (Harms et al., 1975; Dott and Bourgeois, 1982; Duke, 1985; Dumas and Arnott, 2006). Due to the limited width of core, bedforms of F3 and F4 deposits look very similar. However, the two facies are differen- tiated based on a subtle grain size differences between upper very fine-grained sandstone of F3 and the lower fine-grained sandstone of F4, as well as the more significant lateral extent of F3. Additionally, local angular to rounded mudstone rip up clasts represent a greater preservation potential due to higher aggradation rates of amalgamated hummocky cross-stratification, relative to swaley cross-stratification (Dumas and Arnott, 2006). This is together with a more -gener al Cruziana ichnofacies assemblage (MacEachern and Pemberton, 1992) and higher bioturbation intensities in F3 relative to F4. F3 is interpreted to be deposited at, or below, fair-weather wave base (Leckie, 1983; MacEachern and Pemberton, 1992), with fair-weather mudstone deposits preserved mainly as mudstone rip up clasts.

2.4.5 F4 –Swaley cross-stratified sandstone

Facies 4 ranges in thickness from 5 to 12 m and is composed of fine-grained sandstone with rare dispersed granule to pebble sized chert grains on bedding planes and laminae (Fig. 2.7H). Beds display sharp low angle basal erosional surfaces, with bed and bed set thickness ranging from 5 to 150 cm. Internally beds display low angle planar and rarer converging laminae. However, intervals commonly show no distinct original sedimentary fabric, instead displaying a fuzzy texture, likely a result of cryptic bioturbation (Fig. 2.7K) (Rouble and Walker, 1997; Pemberton et al., 2008). F4 is interpreted to be dominantly comprised of swaley cross-stratification (Fig. 2.7I). Trace fossils in F4 in decreasing abundance include Palaeophycus, Ophiomorpha, fugichnia, Rhizocorallium, and Cylindrichnus.

Sandstone beds of F4 are interpreted be dominantly swaley cross-stratified, formed during storms or high wave-energy (Leckie and Walker, 1982; Duke, 1985; Dumas and Arnott, 2006), with less abundant amalgamated hummocky cross-stratified beds. Dispersed granule and pebble sized chert grains present on laminae were transported seaward during storms (Hunter

23 et al., 1979; Rouble and Walker, 1997; Clifton, 2006). It is common that entire vertical sandstone successions are totally devoid of trace fossils, likely due to storm scouring of the upper bioturbated portion of older beds, either a result of high frequency or intensity of the storms (MacEachern and Pemberton, 1992). F4 is interpreted to have been deposited in a storm- and wave-dominated middle shoreface, mostly above fair-weather wave base (Leckie, 1983; MacEachern and Pemberton, 1992). Note that within a few of the cored intervals the boundary between lower and middle shoreface are indistinguishable, as subtle sedimentological differences between F3 and F4 are not present.

2.4.6 F5 - Trough cross-stratified and parallel laminated sandstone and conglomerate

Facies 5 ranges in thickness from 3 to 10 m and is mainly composed of fine-grained sandstone with minor dispersed, to layers up to 5 cm thick, granule to pebble sized chert grains on bedding planes and laminae, as well as clast and matrix supported pebble conglomerate that are poorly sorted with a sandy matrix. F5 either slightly fines upwards or has the same grain size vertically. High angle laminae, trough cross stratification (Fig. 2.7J), low angle planar laminae are common with occasional current ripple laminae. Bed or bed set thickness ranges from 5 to 80 cm. Chert granules and pebbles grains are more common at the base of beds and in places show imbrication (Fig. 2.7M). Carbonaceous debris is locally present. Trace fossils in F5 in decreasing abundance include Macaronichnus segregatus (Fig. 2.7L), root traces (Fig. 2.7N) and fugichnia, with cryptic bioturbation a common texture. Low angle planar laminae commonly overlies trough cross stratification. The uppermost sandstone contain in place root traces below an overlying coal seam.

The upper portions of the shallowing upwards succession consist of dominantly trough cross stratification, interpreted as forming as a result of longshore and rip currents within high an energy wave-dominated environment (Hunter et al., 1979; Leckie, 1983; Rouble and Walker, 1997; Schmidt and Pemberton, 2004). Low angle planar laminae represent the swash and back- wash processes on a beach (MacEachern and Pemberton, 1992). Bioturbation is pervasive in

24 sandstone beds with Macaronichnus segregatus in the upper shoreface to foreshore transition zone, supporting deposition in a high-energy shoreface environment (Clifton and Thompson, 1978; MacEachern and Pemberton, 1992). F5 is interpreted to have been deposited in the surf zone and swash zone, within a wave-dominated upper shoreface to foreshore setting.

2.4.7 F6 - Interbedded sandstone, mudstone and coals

Facies 6 is composed of interbedded coal, mudstone, silty mudstone, and very fine- to medium-grained sandstone. Sandstone beds are trough cross stratified, current and climbing rippled, with a fining upward trend. Large, 1 to 10 cm, angular mud rip up clasts and rounded

sideritized clasts are common (Fig. 2.7P). No trace fossils were observed in this facies.

No marine indicators were observed within F6 which is stratigraphically positioned above marine facies F4 and F5. F6 is interpreted as non-marine coastal plain and fluvial channels of the Upper Mannville undifferentiated.

2.4.8 F7 –Finer grained coarsening upwards succession

Facies 7 is composed of muddy siltstone to siltstone, and very fine- to fine-grained sandstone, displaying an overall coarsening upwards trend. Thin mm to cm scale silt- and sandstone interbeds show abundant mm scale silty normal graded beds (Fig. 2.7R), and common starved current ripples and soft sediment deformation. Fine-grained sandstone show horizontal to wavy laminae intercalated with current ripple laminae (Fig. 2.7Q); abundant carbonaceous laminae and debris occurs within the sandstone interval. Bed or bed sets thicknesses within sandstone intervals range from 5 to 25 cm. Trace fossils within siltstone beds in decreasing abundance include Planolites, Phycosiphon, Teichichnus and Asterosoma. F7 ranges in thickness from 4 to 12 m, and transitions laterally seaward into F4 and F5 deposits where accommodation space increases.

Normally graded silt- to sandstone beds are interpreted as hyperpycnites (Bhattacharya and MacEachern, 2009) and starved current ripple beds likely reflect wave induced unidirection-

25 al currents. Massive mudstone intervals and associated soft-sediment deformation is attributed to rapid deposition of fluid mud (Hovikoski et al., 2008; Ichaso and Dalyrmple, 2009). Current ripple sandstone intercalated with parallel low angle laminae are likely deposited from bed load bottom currents (Gingras et al., 2002). While upwards increasing sand content reflects contin- ued shoaling (Gingras et al., 2002). F7 is interpreted to represent a low gradient, dissipative shoreline prograding into relatively very shallow water above fair-weather wave base (Gingras et al., 2002; Hovikoski et al., 2008).

2.4.9 F8 – Sandstone and organic mudstone

Facies 8 is composed of dark and light grey mudstone, bentonite layers, siltstone, and very fine- to fine-grained sandstone. Dark mudstone intervals are massive to wavy laminated, with starved current ripples, soft-sediment deformation and containing Planolites and unidentifiable bioturbation (Fig. 2.7U). Light grey mudstone and siltstone contain lenticular bedding with common starved current ripples and soft-sediment deformation (Fig. 2.7T). Trace fossils in decreasing abundance include Planolites, Gyrolithes and unidentifiable bioturbation. Bentonite layers are thin, < 10 cm, and typically mappable within several surrounding wells. Mudstone intervals can gradationally coarsen into very fine-grained sandstone which contain intervals of current ripple laminae, horizontal to wavy laminae and be structureless (Fig. 2.7S). Trace fossils within structureless sandstone intervals include Rosselia and Diplocraterion. Fine-grained sandstone beds, which are 1-3 m thick, are trough cross-stratified, display a fining upward trend, have local abundant carbonaceous laminae, and contain cryptic bioturbation. F8 ranges in thickness from 2 to 6 m.

Small-scale, 2 to 4 m, coarsening upwards successions are interpreted as the infilling of interdistributary bay areas by a ‘lacustrine delta fill’ (Coleman, 1966). Thin, 2 to 3 m, fining upwards sandstone intervals which are trough cross-stratified, are interpreted to represent waning unidirectional flow in marine deltaic distributary channels (Elliot, 1974). F9 is interpreted as deposits directly behind and adjacent to contemporaneous shorelines, where dominantly mud-

26 stone deposits represent interdistributary bay and lagoons and dominantly sandstone intervals represent deltaic distributary channels (Elliot, 1974).

2.4.10 F9 – Thick fining upwards sandstone

Facies 9 is composed of very fine- to fine-grained sandstone. Sandstone beds are dominantly trough cross-stratified (Fig. 2.7V) and in places contain wavy laminae. Carbonaceous debris and laminae are abundant when locally present. No trace fossils were observed, with cryptic bioturbation a common texture. F9 ranges in thickness from 14 to 18 m.

F9 deposits are laterally confined and therefore not very mappable within the study area. In a few areas where they can be correlated suggests a general trend to the north-northeast, consistent with age-related incised channel fills (Rosenthal, 1988; Brownridge and Moslow, 1991). F9 is interpreted as incised channels into older strata and are contemporaneous to an unknown younger shoreline farther to the north and likely reflect an associated relative sea-level fall.

2.4.11 Depositional Environment

Some areas with close spaced core show significant along shore facies variability, suggesting potentially variable wave- to river-influenced depositional settings. Cored intervals of thick conglomerate beds likely deposited within close proximity to a distributary channel (Ar- nott, 1993; Caddel and Moslow, 2004; Zonneveld and Moslow, 2004), further associated with proximity to the mountains providing the steep gradient necessary for pebble grains to be transported to the coast (Leckie, 1986; Leckie, 2003). Sandstone and conglomerate intervals displaying abundant carbonaceous laminae and debris are interpreted as phytodetrital pulses, representing both increased precipitation rates and fluvial discharge with proximity to a distributary channel as well (Rice et al., 1986; MacEachern et al., 2005).

Bioturbation intensities were observed as overall very low throughout the study area. The trace fossils observed within lower portions of the coarsening upwards succession demon-

27 strate tiered relationships within heterolithic bedding, where variation of trace fossil diversity, and morphologies, associated with fair-weather and event beds were observed (MacEachern et al., 2010). The trace fossils observed within the upper portions of the coarsening upwards succession are of a low diversity, stressed expression, of the Skolithos ichnofacies. In general, within these shallowing upwards successions Cruziana and Skolithos ichnofacies assemblages occur in lower and upper portions respectively, however there is a mixture of elements. Few instances showed a diminished size of trace fossils (e.g. Asterosoma). Therefore, some evidence suggests brackish conditions, leading to a more overall deltaic interpretation. However, a lack of suspension-feeding structures within proximal areas is not a strong indicator for proximal deltaic settings due to high storm- and wave-reworking leading to a low preservation potential (Howard and Reineck, 1981; DesRoches, 2008). Further, these are the southern shorelines of a far reach- ing northern embayed, shallow, epicontinental sea, which therefore likely did not reach fully marine conditions.

Ten facies are discussed herein, and an overall wave-dominated delta shoreline is interpreted for the basal progradational Falher. This is based on the dominance of storm and wave bedforms and an absence of tidal bedforms, suggesting a low tidal resonance of the basin, high wave effectiveness. A low A/S ratio and straight to lobate shoreline morphology further suggest wave-dominated and wave-dominated, fluvial-influenced coastal processes (Ainsworth et al. 2011).

The main facies difference between the basal Falher parasequence sets in this study and the younger middle and upper Falher parasequence sets is the dominance of fine-grained dissipative shorelines (Short, 1996) in this study of the basal Falher, and mixed sandstone to conglomerate reflective shorelines (Short, 1996) in the middle and upper Falher parasequence sets (Armitage et al., 2004; Zonneveld and Moslow, 2004).

28 2.5 Stratigraphic Framework

2.5.1 Stratigraphic Datum

Choosing a stratigraphic datum that represents a near horizontal and time-correlative surface is always difficult, particularly when correlating over large distances of up to 100 km. Within the studied succession, five separate progradational parasequence sets were identified. It is assumed that the thin coals capping most parasequence sets, and any relatively thick coal seams (> 5 m thick), are near horizontal surfaces during shoreline progradation and may be used as local datums. For cross-section B, which is shown to highlight the stratigraphic architecture of the studied succession, various coals within the Spirit River Formation and the top of the Bluesky Formation were used as local datums where appropriate. Each datum was adjusted accordingly to the adjacent datum along the length of the cross-section. The top of the Bluesky was not used as the datum across the entire cross-section due to the stepwise transgression of the Moosebar Sea, and its erosional nature of the upper Bluesky, related to small-scale transgressive and regressive events during overall transgression (Rosenthal, 1988; Hayes et al., 1994). The datum for cross-sections X-X’, Y-Y’ and Z-Z’ is the coal directly overlying the Falher L parasequence set. The coal is thicker (5 m) in the east and thinner to the west (2 m).

2.5.2 Studied Succession Stratigraphic Architecture – Cross-Section B-B’

Cross-section B is orientated south to north and highlights the stratigraphic architecture of the five parasequence sets within the studied succession (Fig. 2.8A). The maximum amount of non-marine vertical aggradation of the entire succession is estimated to be 15 m, when applying a moving datum between coals or at the top of the Bluesky Formation, along depositional dip over a horizontal distance of 110 km. Thick shoreline sandstone bodies of each successively younger parasequence set are entirely offset from the underlying parasequence set to the north and paleo seaward. These stacking geometries of parasequence sets indicate a strongly progradational shoreline succession with little aggradation. This stacking geometry of parasequence

29 A)

South B 6.8 km 11.4 km 4.9 km 13.3 km 5.0 km 7.1 km 6.2 km 7.7 km 8.3 km 15.5 km 5.2 km 14.9 km B’ 16-03-051-18(API) W5 (API) (API) (API) (API) (API) (API) (API) 04-19-050-18(API) W5 (API) North 13-29-046-15 W5 13-34-046-16 W5 16-26-047-17 W5 06-10-048-17 W5 11-33-048-18 W5 05-17-049-18 W5 14-35-049-19 W5 0 150 15-30-051-18(API) W5 06-23-052-20(API) W5 10-02-053-20(API) W5 12-18-054-20 W5 0 150 0 150 0 150 0 150 0 150 0 150 0 150 0 150 0 150 0 150 0 150 0 150 Upper Mannville Upper Mannville undiﬀerentiated undiﬀerentiated

Falher K Falher L mFS 4 Falher M mFS 3 Falher N Falher O mFS 2

mFS 1 mFS 0 Wilrich Wilrich

Bluesky Fm

Gething Fm Bluesky Fm

20 km 20 m Shoreface sandstones Coal horizon B) T 58 Marine mudstones Major marine ﬂooding surface Falher K N Non-marine coastal Fluvial channel

Cored interval T 56

B’ T 54

Figure 2.8 - A) Depositional dip orientated cross section show- Falher L Falher M ing the stratigraphic architecture of studied succession. B) Each T 52 basal Falhers progradational hightstand parasequence set net Deformed Belt sandstone map. T 50

Falher N

T 48 > 10 m Core control > 15 m 5 Isopach thickness (m) > 20 m Onset of top Falher L parasequence set > 25 m T 46 lowstand B Falher O

30 R 27 R 25 R 23 R 21 R 19 R 17 R 15 R 13 W5 set sand bodies is significantly different compared to the strongly aggradational stacking of the middle and upper Falher parasequence sets, where each successively younger sand body is only slightly offset paleo seaward by a few km’s (Leckie, 1986). Sandstone bodies of parasequence sets are initially thin overlying the major flooding surfaces where limited accommodation exists; sandstone thickness then increases at the location where the previous parasequence set sandstone body begins to thin and unfilled accommodation space increases (Fig. 2.8A). Maximum sandstone thickness within parasequence sets ranges between 20 to 30 m. The sand bodies of each parasequence set are lens shaped and span up to 80 km in a progradational dip direction with the thick main sand bodies spanning 15 to 45 km in a progradational dip direction (Fig. 2.8A).

This cross-section best illustrates the time correlative mudstone dominated offshore Wilrich Member seaward and underlying the sandstone dominated shoreline Falher Member, as well as the landward and overlying interbedded non-marine Upper Mannville undifferentiated deposits, similar to Zonneveld and Moslow (2004). Note the major marine-flooding surfaces are distinct surfaces in the nearshore areas but the correlative surface becomes indistinct both seaward within Wilrich mudstone intervals and landward within non-marine Upper Mannville undifferentiated deposits.

2.5.3 Falher N Facies Architecture – Cross-Sections X-X’, Y-Y’ & Z-Z’

Three parallel cross-sections X-X’, Y-Y’ and Z-Z’, are orientated perpendicular to the paleo-shoreline and highlight the facies architecture of the Falher N parasequence set (Fig. 2.9). Northward and paleo-seaward, facies transitions from non-marine F6, to nearshore proximal marine F5 and F4, and lastly distal marine F3 and F2 are observed within the Falher N parasequence set. A complete vertical expression of this coarsening upwards facies succession was not observed in core, nor inferred from geophysical well logs responses within a single parasequence set within the study area.

Paleo water depth is approximated as the thickness of the prograding parasequence

31 sets, the isopach between the top of underlying major marine-flooding surfaces to just below coals capping parasequence sets or their horizontal projection where coals are not present, note as compacted thickness (Klein, 1974). This is likely an overestimation for paleo water depth, as it is highly likely that these are stacked shoreline parasequences with indistinguishable flooding surfaces within, as suggested by anomalously thick sandstone intervals, > 20 m in places (Fig. 2.8B). This isopach also directly provides the interpreted paleo subaqueous profile (Fig. 2.10). Note that minor erosion during transgression has locally occurred and despite a high con-

5.0 km 5.4 km 3.2 km 5.6 km 7.2 km 4.0 km 5.2 km 6.2 km X 11-33-048-18 W5 05-17-049-18 W5 10-26-049-19 W5 07-03-050-19 W5 01-18-050-19 W5 13-35-050-20 W5 03-14-051-20 W5 07-34-051-20 W5 04-17-052-20X’ W5 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150

Upper Mannville undiﬀerentiated

Falher L

mFS 3 Falher M

Falher N

mFS 2

mFS 1

Bluesky Fm mxFS

Gething Fm

9.1 km 1.9 km 2.6 km 3.4 km 4.7 km 3.7 km 7.1 km 6.3 km Y 06-20-049-17 W5 12-13-050-18 W510-23-050-18 W5 04-35-050-18 W5 16-03-051-18 W5 06-21-051-18 W5 15-30-051-18 W5 13-13-052-19 W5 11-33-052-19Y’ W5 0 (API) 150 0 (API) 1500 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 Upper Mannville undiﬀerentiated

Falher L

mFS 3

Falher M Falher N

mFS 2

mFS 1

Bluesky Fm mxFS

Gething Fm

32 Z 3.9 km 4.7 km 9.7 km 5.5 km 5.9 km 8.2 km Z’ 10-17-050-16 W5 16-28-050-16 W5 10-09-051-16 W5 01-21-051-17 W5 06-04-052-17 W5 10-19-052-17 W5 10-04-053-18 W5 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 0 (API) 150 Upper Mannville undiﬀerentiated

Falher L

Falher M mFS 3

Falher N mFS 2

mFS 1

mxFS Bluesky Fm

Gething Fm

Facies F1 Facies F4 & F5 Coal horizon 20 m Facies F2 Facies F6 Major marine ﬂooding surface 250 X V.E.

Facies F3 Cored interval 10 km

B) Portion of Falher N net SS map mFS 2 Isopach Map

T 53 T 53 Z’ Z’ > 18 m N Y’ 3 m N Y’ 15 m T 52 X’ T 52 X’ 12 m 6 m 9 m 9 m 6 m > 18 m 3 m 12 m 15 m T 51 > 18 m T 51

15 m

3 m T 50 6 m T 50 Z Z 9 m 12 m 12 m Deformed Belt Deformed Belt 9 m 15 m 6 m Y T 49 > 18 m Y T 49 3 m Cross section reference

Falher N Falher N Core control capping coal capping coal X X Well control limit limit T 48 T 48 3 Contour interval

R 21 R 19 R 17 R 15 W5 R 21 R 19 R 17 R 15 W5 Figure 2.9 - A) Three parallel, shoreline normal orientated cross-sections highlighting facies architecture of the Falher N parasequence set. B) Falher N net sandstone map and isopach map between underlying major flooding surface and just under the Falher N capping coal, o its horizontal projection where the coal is not present. centration of controlling wells for picking surfaces, the interpreted gradients of the subaqueous profiles are a minimum. Based on cross-sections; B-B’, X-X’, Y-Y’ and Z-Z’, water depths during progradation were relatively shallow, ranging less than 20 to up to 30 m and averaging 25 m.

33 0

Mississippi

5 Ebro Niger

10 Sao Francisco Danube Senegal Nile

Daytona Beach Gold Beach Average basal Falher

Water depth (m) depth Water 15

20 0 5 10 15 20 Distance seaward (km) Figure 2.10 - Estimated paleo subaqueous profile for the basal Falher shown by orange dashed line, modified from Wright and Coleman, 1972. Calculated and averaged from six cross-sections using the Falher N and Falher M isopachs of the mFS 2 and mFS 3 to a coal horizon, or its horizontal projection respectively.

2.6 Discussion

2.6.1 Sheet Sand Body Facies Architecture and Geometric Characteristics in a Low Accommo- dation and Gradient Setting

Strongly progradational shorelines deposited within shallow, low angle ramp settings can display unusual stratigraphic architecture in a dip direction, where they often show sharp-based shoreline sandstone with broad facies belts (Fig. 2.11). In a seaward direction, conformable successions of F2 and F3 deposits are observed where there is greater accommodation space (Fig. 2.9 & 2.11). However, in a landward direction F2 deposits are absent, resulting in the observed sharp-based nature of the shoreline (Fig. 2.6, 2.9 & 2.11).

Distal interbedded sandstone and mudstone beds of F2 are laterally continuous and ex- tend significantly in a seaward direction. Core within the distal facies of F2 show an abundance of erosion at base of beds, demonstrated by basal scouring of very fine-grained sandstone beds (Fig. 2.11). The result of the relatively shallow to flat underlying subaqueous profile (Fig. 2.10) together with shallow water depths, led to the sea floor mainly being above storm wave base.

34 A) 01-21-051-17 W5 Depth (m) Gamma Ray Stratigraphic & Strat. Facies Unit (API) A B D Surface 0 75 150

M. F6 Up. B

F7 2650 m Falher L Falher mFS 3 F1A

2660 m F4 Falher M Falher F3 C

mFS 2 D F1A

Spirit River Formation Spirit River 2670 m F4

F3 C F1A

Falher N Falher mnFS 2680 m F3 F2 F1A mnFS F3 mFS 1 2690 m F2 Figure 2.11 - A) A,B,C Erosional scouring of sandstone beds in distal

Wilrich A portions of F2. D Sharp based shoreline of the Falher M parasequence set. B) Schematic cross-sections illustrating low angle ramp gradient and F1 Fm

Bluesky shallow water depth, with storm wave base always being below the sea floor. B) Time 1 - Early progradation

D Previous parasequence Storm wave base set progradation

Time 2 - Later progradation

A Storm wave base

Facies F3 Facies F1 ~40 km Facies F2 Facies F4 & F5

This resulted in a relatively high degree of erosion, with sea floor agitation from waves facilitat- ing significant transport of fine-grained sediments into the deeper parts of the basin (Traykovski et al., 2000; Runkel et al., 2007; Varban and Plint, 2008; Bhattacharya and MacEachern, 2009).

35 This resulted in wide broad facies belt within single a parasequence set in a dip direction, which is not observed vertically within a single parasequence set (Fig. 2.9 & 2.11). Thus, within the offshore transition facies of F2, the sedimentation rate was only slightly greater than the erosion taking place, with relatively low accumulation rates (Kuehl et al., 1986; Alexander et al., 1991).

In a landward direction, erosion rates for F2 deposits from shoaling waves in shallower water depths were significantly higher than F2 sedimentation rates, leading to negligible, if any, F2 accumulation. F2 was primarily deposited distally where water depths and accommodation space were greater, and the probability of wave erosion was less (Peters and Loss, 2012). This

resulted in sediment bypass and non-deposition of F2 deposits in nearshore areas during shoreline progradation (Varban and Plint, 2008). Furthermore, based on cross-sections previously described and shown, the resultant sharp-based nature of the shoreline sandstone bodies is not associated with any indication of a relative sea level fall or forced regression (Plint, 1988; Posa- mentier and Morris, 2000). The presence and / or absence of interbedded F2 deposits underlying shoreline deposits is a combined result of variables such as rate of sedimentation and rate of erosion, which are intrinsically linked to water depth and associated wave energy (Cant, 1984; Helland-Hansen and Martinsen, 1996).

In a strike direction along shore, the Falher N parasequence set is represented by three parallel shore normal cross-sections, to specifically highlight offshore facies architecture variation (Fig. 2.9). The Falher N net sandstone map (Fig. 2.9B) shows variability in distal sandstone thicknesses, with thicker, more extensive and continuous sandstone in the east relative to the west. From west to east, the isopach map reflecting the paleo subaqueous profile (Fig. 2.9B), together with cross-sections X-X’, Y-Y’ and Z-Z’, shows a steeper subaqueous profile gradient on the western side and a shallower gradient to the east. This example highlights an apparent disconnect between nearshore and offshore sedimentation. Using a high density well control, it is interpreted that offshore geostrophic currents play a significant role in distal storm deposited facies distributions and sandstone extent (Fig. 2.12) (Duke et al., 1991; Varban and Plint, 2008).

36 X N Y Surface wave Z

20 m Surface wave Geostrophic ﬂow

5 to 10 km X’ F4 & F5 Geostrophic ﬂow Y’ 5 to 40 km Z’ Facies F1 Facies F3 F3

Facies F2 Facies F4 & F5

Figure 2.12 - Cartoon block diagram illustrating along shore strike variation in offshore storm sedimentation.

2.6.2 Controls on Parasequence Set Stacking Patterns within an Active Foreland Clastic Wedge

Cross-section A shows a distinct difference in parasequence set stacking patterns of the basal progradational Falher, compared with aggradational parasequence sets of the middle and upper Falher (Fig. 2.5). This is in contrast to traditional sequence stratigraphic models of a dominantly aggradational to then progradational stacking pattern within highstand systems tracts following a maximum flooding surface (Vail, 1987, Posamentier and Vail, 1988). However, the Pembina Channel (Hayes et al., 1994), and a mineralogy change of decreasing volcanic detritus across this transition from the progradational to aggradational stacking pattern (Brian Zaitlin, pers. comm., 2017), potentially reflects a significant sequence boundary separating the prograding and aggrading successions. On the eastern side of the province the Grand Rapids Formation is the age equivalent strata, it is overall thinner (< 100 m) compared to Spirit River Formation thicknesses (> 400 m). The thickness difference suggests the influence of tectonic loading in the fold and thrust belt was more significant in creating accommodation space on the western side of the province. The Grand Rapids Formation in eastern Alberta has informally been divided into seven allomembers (e.g. Morshedian et al., 2012; Pouderoux et al., 2015), as well as a Lower

37 and Upper Grand Rapids Formation. The boundary between Lower and Upper Grand Rapids Formation is a significant sequence boundary of long-term subaerial exposure located at the top of the Sparky Allomember (Pouderoux et al. 2015). Biostratigraphic age constraints within the Upper Mannville are notably of poor resolution, which hinders a definitive correlation of this sequence boundary across the basin. However, it is possible this basin-wide sequence boundary is expressed as a type 1 sequence boundary in the lower subsidence eastern area, and almost a type 2 sequence boundary in the higher subsidence area to the west. Overall, evidence suggests that the basal Falher, and middle and upper Falher, are two different depositional sequences, and therefore have independent controls resulting in the drastically different stacking patterns observed within the Spirt River Formation.

The following discussion highlights the possible basin-scale controlling factors on creation of accommodation space and sediment supply. Isopachs of Mannville stratigraphy across Alberta show a significant change in geometry, from a relatively uniform east-west thickness within the Lower Mannville, to a major thickening of sediments westward in the Upper Mann- ville (Hayes et al. 1994). The Mannville clastic wedge has been linked to accretion of the Bridge River Terrane, thrusting in the cordillera would lead to variable loading and episodic subsidence in the foreland basin (Cant and Stockmal, 1989). However, recent work supports a relationship of cyclical high-flux magmatism, with associated plateau uplift and increased sediment supply, due to foundering of an eclogitic root in the orogenic belt, to foreland basin clastic wedge deposition (DeCelles et al. 2009; Quinn et al. 2016). This was highlighted within the upper portion of the Mannville clastic wedge, where an evolving provenance within the Spirit River Formation was observed, from broad age spectra within Falher D and Falher A, to a dominated Mesozoic mode in the Notikewan (Quinn et al., 2016). Further, a high-flux episode associated with a detrital zircon mode at 115 Ma (Quinn et al., 2016), near the end of Gething Formation deposition, would be related to plateau uplift and is interpreted to cause initial basin subsidence leading to the transgression of the Moosebar Sea. The Bluesky Formation was then deposited in an overall retrogradational parasequence set stacking pattern. Note, it is more complicated to the south of

38 this study area, with shoreline parasequences and incised channel complexes representing higher frequency relative-sea level changes within the Glauconitic / Bluesky Formation stratigraphic interval (Hayes et al., 1994); where this interval is likely an older depositional sequence.

Stacking patterns represents the interplay of the sediment supply (S) and the creation of accommodation space (A). The mainly progradational character of the older Falher parasequence sets reflects that the rate of sediment supply was greater than the creation of accommodation space (S>A) (Van Wagoner et al., 1988). The basal Falher parasequence sets demonstrate a low degree of aggradation, suggesting that creation of accommodation space at the shoreline was not significant (Fig. 2.13). Following plateau uplift, and basin subsidence, is a period of likely very high sediment input into the basin during deposition of the strongly progradational basal Falher.

The dominantly aggradational younger Falher parasequence sets reflect that the rate of sediment supply is more or less equal to the creation of accommodation space (A=S) (Van Wagoner et al., 1988). Through time, either sediment supply must have decreased or creation

Vertical component

Incremental Middle and stratigraphic vector Upper Falher

Basal Falher

Figure 2.13 - Schematic showing creation of accommodation space at the shoreline during Spirit River Formation clastic wedge deposition.

39 of accommodation space must have increased. Based on cross-section A, the Spirit River Forma- tion is seen prograding northward into an area of high subsidence (Fig. 2.13). The epeirogenic movement of the active subsiding Peace River Arch during the Early Cretaceous could have created additional accommodation space and controlled the area of the aggradational stacking of the middle and upper Falher parasequence sets; as well as shaping the northern limit of Falher shoreface progradation and southern limit of transgressions between Falher parasequence sets (Leckie 1986; Cant, 1996). The potential shelf break point, caused by the southern limits of the subsiding Peace River Arch could be where sediment supply and progradation could not over- come the unfilled accommodation space to the north. However, the entire western side of the basin could be subsiding at an overall increased rate during this time due to increased tectonic loading within the cordillera and subsequent basin subsidence (Leckie, 1986). This is supported by punctuated relative-sea level rises, as shown by 10 to 20 m of creation of accommodation space between Upper Falher parasequence sets (Fig. 2.5). Further, each Upper Falher parasequence set contains a significant conglomeratic portion, which requires a steep gradient to transport gravels to the shoreline (Leckie, 1986). Increased tectonic activity through time is interpreted to have increased creation of accommodation space because the isopach thickness of the Spirit River Formation clastic wedge does not significantly change from south to north (Fig. 2.5), demonstrating that Peace River Arch subsidence was not primarily controlling increases in creation of accommodation space. A relatively consistent rate of sediment supply to the basin is assumed throughout the Spirit River Formation deposition given the northward axial progradation of the Falher shorelines and mixture of western derived sediments. Although if sediment supply into the basin remained relatively constant, sediment supply at the shoreline would have decreased due to increased accumulation of coastal plain deposits associated with the shoreline progradation (Cross et al., 1993; Muto and Steel, 1997).

2.7 Conclusions

40 Well log and core correlations has revealed the stratigraphic architecture and regional stratigraphic framework of the basal progradational Falher, petroleum industry referred ‘Wil- rich’. The identification of sequence stratigraphic surfaces allows for the subdivision of the ‘Wil- rich’ sandstone sheet into five laterally northward accreting parasequence sets within the study area. Based on cored wells, sedimentary facies were picked and correlated between wells based on geophysical well log response, showing variations in facies thickness, lateral extent and presence; are highlighted using shoreline dip orientated cross-sections. The following are the main conclusions:

1. The petroleum industry referred ‘Wilrich’, dominantly progradational Falher herein, is the older and geographically southern parasequence sets of the Spirit River Formation clastic wedge.

2. Applying multiple local datums, coals and the top of marine flooding surfaces, as an overall moving stratigraphic datum for long distances cross-sections results in a more accurate representation of the stratigraphic architecture.

3. Wide facies belts are attributed to the relatively shallow to flat underlying subaqueous profile, together with shallow water depths, leading to wave base remaining present farther seaward which likely facilitated significant seaward transport of offshore sediments.

4. Sharp-based shoreline sandstone bodies can be interpreted as a combined result of variables of rate of sedimentation and rate of erosion, which is intrinsically linked to shallow water depth and associated wave energy.

5. Longshore geostrophic currents, as shown by facies mapping and cross-sections in a high density well analysis, played an important role in offshore directed storm sand deposition.

6. The regional parasequence set stacking pattern of the Spirit River Formation clastic wedge is attributed to two different depositional sequences which had independent

41 basin controlling factors influencing creation of accommodation space and sediment supply. Initially, sediment supply was far greater than creation of accommodation space during the basal progradational Falher. Creation of accommodation space increased during the upper aggradational Falher due to increased tectonic loading and subsequent basin subsidence, although sediment supply to the shoreline may have decreased as well, due to increased coastal plain deposition.

2.8 References Alberta Study Group, 1954, Lower Cretaceous of the Peace River Region, in L. M. Clark, ed., Western Canada Sedimentary Basin, American Association of Petroleum Geologists, Rutherford Memorial Volume, p. 268-278. Ainsworth, R.B., Vakerelov, B.K., and Nanson, R.A., 2011, Dynamic spatial and temporal predic- tion of changes in depositional processes on clastic shorelines: toward improved subsurface uncertainty reduction and management: AAPG Bulletin, v. 95, p. 267-297. Alexander, C.R., DeMaster, D.J., and Nittrouer, C.A., 1991, Sediment accumulation in a modern epicontinental-shelf setting: The Yellow Sea: Marine Geology, v. 98, p. 51-72. Armitage, I.A., Pemberton S.G., and Moslow, T.F., 2004, Facies succession, stratigraphic occurrence, and paleogeographic context of conglomeratic shorelines within the Falher “C”, Spirit River Formation, Deep Basin, west-central Alberta: Bulletin of Canadian Petroleum Geology, v. 52, no. 1, p. 39-56. Arnott, R.W.C., 1993, Sedimentological and stratigraphic model of the Falher “D” pool, Lower Cretaceous, northwestern Alberta: Bulletin of Canadian Petroleum Geology, v. 41, no. 4, p. 453- 463. Bhattacharya, J.P., 1993, The expression and interpretation of marine flooding surfaces and erosional surfaces in core; examples from the Upper Cretaceous Dunvegan Formation, Alber- ta foreland basin, Canada, in Posamentier, H.W., Summerhayes, C.P., Haq, B.U. and Allen, G.P. (eds.). Sequence Stratigraphy and Facies Associations. International Association of Sedimentolo- gists Special Publication, v. 18, p. 125-160. Bhattacharya, J.P., and Walker, R.W., 1991, Allostratigraphic subdivisions of the Upper Creta- ceous Dunvegan, Shaftesbury, and Kaskapau formations in the northwestern Alberta subsurface: Bulletin of Canadian Petroleum Geology, v. 39, p. 145-164. Bhattacharya, J.P. and MacEachern, J.A., 2009, Hyperpycnal rivers and prodeltaic shelves in the Cretaceous seaway of North America: Journal of Sedimentary Research, v. 79, p. 184-209. Brownridge, S. and Moslow, T.F., 1991, Tidal estuary and marine facies of the Glauconite Mem-

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48 Chapter Three: Reservoir Characterization of Tight ‘Wilrich’ Sandstone Reservoirs, Spirit River Formation, west-central Alberta 3.1 Introduction

In order to achieve the goal of mapping and evaluating reservoir properties of the ‘Wilrich’, thin sections and their petrology were analyzed to describe their overall grain texture, mineralogy, and diagenetic processes in this chapter. These observations were then used to integrate with lab measured petrographic data and geophysical well log responses to evaluate dominant controls.

The main objectives of this chapter are to integrate petrographic observations with lab measured data to: 1) characterize the grain texture, mineralogy, and provenance of ‘Wilrich’ sandstone units; 2) establish the paragenetic sequence to determine the control on permeability within ‘Wilrich’ sandstone units; 3) determine what grain textures, as a result of diagenetic processes, correspond to greater reservoir quality, i.e. permeability, and relate these diagenetic processes to sequence stratigraphy; 4) discuss potential cause for varying resistivity log responses within different shoreline sandstone facies.

3.2 Study Area and Methodology

The study area is 140 by 160 km located in west-central Alberta within the Alberta Deep Basin on the eastern side of the deformation belt spanning T46 to T59 and R13 W5 to R1 W6 (Fig. 3.1). 26 cored wells within the study area, which intersect the interval of interest, were logged in detail for their physical sedimentary structures, lithology and grain size for description of facies, with this chapter focusing on the main reservoir of shoreline facies F3, F4 and F5. Four of the cored wells were analyzed in detail with measured permeability and thin sections.

In seven of the cores, thin sections were sampled within different facies across significant boundaries marked by grain size and resistivity log changes. 31 thin sections were cut and

49 T59 Alberta N Saskatchewan

British Columbia T56

Study Area Edmonton T53

Calgary Deformed Belt T50 U.S.A 200 km to 12.5 to 21307.8 Gas Cnd Cumulative production BOE Ratio - 10 : 1 T46

R1 W6 R26 R24 R22 R20 R18 R16 R13 W5 Core control Detailed petrographic 20 km analysed core Well control Producing ‘Wilrich’ horizontal well

Figure 3.1 - Map of study area within Alberta Deep Basin, Canada. Producing horizontal ‘Wilrich’ wells show cumulative production pie charts. prepared using dual carbonate staining. The distribution of thin sections in each facies is, 12 from facies 5, 11 from facies 4, 5 from facies 3, 2 from facies 8, and 1 from facies 1. A sub-set of 10 of the thin sections from 3 cored wells; 00/13-34-046-16 W5, 00/05-17-049-18 W5 and 00/12-18-054-20 W5, were analyzed texturally for grain size distribution and mineralogy using photos in the JMicroVision software.

For each thin section, grain size distributions were determined based on over 300 long axis grain measurements. All measurable grains within the photo field of view were measured to avoid sample bias (Fig. 3.2).

Mineralogy was established by point counting 300 framework grains and authigenic minerals per thin section slide. A random grid using the JMicroVision software was applied, where the software moves cross-hairs randomly across the photo. At each location, the framework

50 A B

500 μm 500 μm

Figure 3.2 - Photos demonstrating result after using JMicroVision software. A) Long axis grain mea- sures denoted by red lines, 40x PPL (12-18-054-20 W5, 2949.7 M); B) small colored dots corresponding to framework grain or authigenic mineral identified, 40x XPL (05-17-049-18 W5, 3204.6 m).

grain or mineral was identified at the center of the cross-hairs (Fig. 3.2), and confirmed using the petrographic microscope. If the cross-hairs landed on the same grain again, the grain was not counted a second time.

Pressure-decay profile permeability (PDPK) measurements were collected on 3 cores; 00/13-34-046-16 W5, 00/05-17-049-18 W5, and 00/13-29-046-15 W5. Slip-corrected gas per-

meability values were collected on the surface of core slabs using the PDPK-400TM (CoreLab,

USA) probe permeameter using N2 gas at a pressure of 24.7 psia. Nitrogen gas flows into the rock unit through a probe rubber tip (O-ring size 0.5X4), which is sealed against a flat core piece, from a pressurized tank. Pressure is then recorded as a function of time, pressure decay, and then using a flow-rate function, gas permeability values were calculated where internal flow resistance is considered negligible (Jones, 1994). Maximum pressure-decay time for each measurement was 30 seconds. Vertical depth profiles were conducted at 10 cm sample spacing. Note profile (probe) permeability values were measured at ambient conditions and have not been corrected to ‘in-situ’ stress conditions in this study.

X-ray fluorescence was collected on the same three cores as PDPK measurements. X-ray fluorescence spectrometry was conducted using a DELTA Premium handheld XRF (Olympus®, USA) on the surface of core slabs. Bulk chemical analysis of major and trace elements were

51 collected by means of exciting the cores with a high energy X-ray incident beam and examining the resultant secondary X-ray wavelength dispersive spectrum. X-ray fluorescence was obtained along the same vertical locations and spacing as the profile (probe) permeability values.

3.3 Results

3.3.1 Grain Texture

For each thin section examined the well location and depth, as well as a summary of grain texture results are listed in Table 3.1. Histograms of the grain size distributions of the three facies comprising the coarsening upwards shorelines are provided in Figure 3.3.

Well & Depth Texture Mean Sorting Framework (Standard Grain Size Wentworth Deviation UWI, Depth (μm) Classiﬁcation of Phi) Sorting Facies 5: Trough cross-stratiﬁed and parallel laminated sandstones and conglomerates 05-17-049-18 W5, 3199.3m 222 UF 0.43 WS

05-17-049-18 W5, 3203.3m 218 UF 0.43 WS

13-34-046-16 W5, 3257.8m 194 UF 0.39 WS

12-18-054-20 W5, 2949.7m 213 UF 0.34 VWS Facies 4: Swaley cross-stratiﬁed sandstone 05-17-049-18 W5, 3204.6m 129 LF 0.34 VWS

13-34-046-16 W5, 3263.6m 142 LF 0.34 VWS

12-18-054-20 W5, 2953.1m 141 LF 0.34 VWS Facies 3: Amalgamated hummocky cross-stratiﬁed sandstone 05-17-049-18 W5, 3213.3m 92 UVF 0.32 VWS

13-34-046-16 W5, 3270.2m 77 LVF 0.40 WS

12-18-054-20 W5, 2959.4m 73 LVF 0.32 VWS Table 3.1 - Table of grain textures on examined thin sections. Wentworth Classifica- tion: LVF – lower very fine-grained; UVF – upper very fine-grained; LF – lower fine- grained; UF – upper fine-grained. Sorting: WS – well sorted; VWS – very well sorted.

52 Grain Size Distribution 700

F5 600 F4 F3 500

400

Frequency 300

200

100

0 62.5 88 125 177 250 350 Silt LVF UVF LF UF LM >UM Wentworth Grain Size (μm)

Figure 3.3 - Grain size distribution histogram from all examined thin sections for all three shoreline facies.

Facies 3 consists of amalgamated hummocky-cross stratified sandstone beds, interpreted to have been deposited within a storm-dominated lower shoreface. Mean framework grain size ranges from 73 to 92 μm, which spans lower very fine- to upper very fine-grained based on Wentworth classification (Wentworth, 1922). The standard deviation of phi grain sizes indicates the sandstone intervals are well to very well sorted, using the classification from Folk (1974).

Facies 4 consists of swaley cross-stratified sandstone beds, interpreted to have been deposited within a wave- and storm-dominated middle shoreface. Sandstone in this facies is classified as lower fine-grained with mean framework grain size ranges from 129 to 142 μm, with the standard deviation of phi grain sizes indicating all studied samples are very well sorted.

53 Facies 5 consists of trough cross-stratified sandstone beds, interpreted to be deposited within a wave-dominated upper shoreface setting. Mean framework grain size ranges from 194 to 222 μm, upper fine-grained sandstone, with the standard deviation of phi grain sizes showing samples to be well to very well sorted.

3.3.2 Mineralogy and Provenance

Framework grain and authigenic mineral percentages for each thin section are summarized in Table 3.2. Figure 3.4 shows an overview of the mineralogy within the 3 different shoreline facies. Point counting revealed all samples plot as a litharenite using a QFL ternary diagram

(Fig. 3.5A). Overall samples from the coarser shallow water facies 5 are more quartz and chert rich than samples from deeper water facies 3 and 4 which are more lithic rich.

The following highlights the various minerals and rock fragments which comprise lithic rock fragments. Pebble and granule chert grains consist of microcrystalline quartz and rarer chalcedonic quartz (Folk, 1974); with chert grains interpreted to be derived from eroded uplift- ed older Mesozoic and Paleozoic limestones to the west (Leckie, 1986). Volcanic rock fragments are mostly felsitic grains with a microcrystalline matrix containing feldspar laths, representing felsic lavas and tuffs (Dickinson, 1970). Sedimentary rock fragments are mostly massive mudstone and argillaceous grains, with their non-resistance to abrasion suggesting a relative short transport distance from their source area, likely from the thrust belt to the west (Dickinson, 1970; Folk, 1974). Low-grade phyllites and schists displaying foliation were identified as metamorphic rock fragments, derived from low-grade metamorphic source areas (Folk, 1974; Leckie, 1986). Muscovite, biotite, and detrital chlorite grains, which are grouped together as micas, with their low resistance to abrasion suggests a short transport distance from their source area; likely derived from low-grade greenschist facies rocks (Leckie, 1986).

On a QmFLt ternary diagram, samples for the basal Falher parasequence sets in this study plot within a recycled orogen provenance (Fig. 3.5C). This is the result of the sandstone

54 Well & Depth Framework Grains (%) Authigenic Minerals (%)

Sedimentary Volcanic Metamorphic Detrital Ferroan Accessory Monocrystalline Polycrystalline Rock Rock Rock Carbonate Carbonate Mineral UWI, Depth Quartz Quartz Feldspar Chert Fragment Fragment Fragment Mica Grain Cement (Clays) Facies 5: Trough cross-stratiﬁed and parallel laminated sandstones and conglomerates 05-17-049-18 W5, 3199.3m 21 7 5 11 13 23 4 1 trace 8 6 05-17-049-18 W5, 3203.3m 19 7 4 9 20 31 4 1 / / 5 13-34-046-16 W5, 3257.8m 30 4 2 9 20 29 2 1 / / 3

12-18-054-20 W5, 2949.7m 26 6 5 6 18 29 5 2 / / 5 Facies 4: Swaley cross-stratiﬁed sandstone 05-17-049-18 W5, 3204.6m 18 6 3 1 22 35 5 2 trace trace 6 13-34-046-16 W5, 3263.6m 25 1 1 5 18 29 2 2 3 12 1 12-18-054-20 W5, 2953.1m 21 3 4 1 23 29 4 3 4 4 4 Facies 3: Amalgamated hummocky cross-stratiﬁed sandstone 05-17-049-18 W5, 3213.3m 20 3 1 / 28 28 2 2 4 6 7 13-34-046-16 W5, 3270.2m 16 1 2 / 24 34 1 1 3 18 1

12-18-054-20 W5, 2959.4m 14 1 trace / 28 28 2 2 6 18 1

Table 3.2 - Table of mineralogy of examined thin sections. 55 A B SRF Fe D M Q M Q

SRF MRF

Fe D VRF VRF

500 μm 1000 μm

C D

Plg Plg Mica Mica

SRF Ak F SRF Ak F M Q M Q

VRF P Q VRF P Q

500 μm 500 μm

E F Plg Plg

P Q P Q

Chrt M Q Chrt M Q

VRF VRF SRF SRF

500 μm 500 μm

Figure 3.4 - Thin section photos for grain size and mineralogy overview of the three shoreline facies. A) F3, 40x PPL (12-18-054-20 W5, 2959.4 m); B) F3, 100x PPL (12-18-054-20 W5, 2959.4 m); C) F4, 40x PPL (05-17-049-18 W5, 3204.6 m); D) F4, 40x XPL (05-17-049-18 W5, 3204.6 m); E) F5, 40x PPL (13-34-046-16 W5, 3257.8 m); F) F5, 40x XPL (13-34-046-16 W5, 3257.8 m). Framework grain and authigenic mineral abbreviations: Ak F: alkali feldspar, Chrt: chert, Fe D: ferroan dolomite cement, M Q: monocrystalline quartz, Mica: biotite, detrital chlorite, and muscovite, MRF: metamorphic rock fragment, P Q: polycrystalline quartz, Plg: plagioclase, SRF: sedimentary rock fragment, VRF: volcanic rock fragment.

56 A) Q 100 0 QUARTZARENITE

90 10 SUBARKOSE SUBLITHARENITE

80 20 Facies 5 70 30 Facies 4 Facies 3

60 40 SRF B)

50 50

40 60

30 70

20 80 VRF MRF 10 ARKOSE LITHIC FELDSPATHIC LITHARENITE 90 ARKOSE LITHARENITE

0 100 Sample point, Falher O, F 100 8090 70 60 50 40 30 20 010 L N, and K (this study) Sample point, Falher D (Leckie, 1986) Qm Qp C) D)

Recycled Orogen Provenance Collision Orogen Provenance

Continental Block Provenances

Magmatic Arc Provenances Arc Orogen Provenance F Lt Lv Ls Figure 3.5 - Ternary diagrams for mineralogy and provenance, included are sample points on middle and upper Falher outcrop equivalents from the Bullmoose Mountain and Mount Spieker area (Leck- ie, 1986). A) Q F L ternary diagram (Folk, 1974): Q – monocrystalline and polycrystalline quartz; F – feldspars; L – all rock fragments including chert. B) SRF VRF MRF ternary diagram for distribution of lithic grains. C) Qm F Lt ternary diagram for provenance: Qm – monocrystalline quartz; F – feldspars; Lt: stable and unstable lithic fragments, including polycrystalline quart, from Dickinson and Suczek, 1979. D) Qp Lv Ls ternary diagram for provenance: Qp – polycrystalline quartz; Lv – volcanic rock fragments; Ls – unstable sedimentary and metasedimentary (metamorphic) rock fragments, from Dickinson and Suczek, 1979.

57 bodies of this study containing a strong mixture of mechanically unstable lithic fragments, and chert grains derived from older Paleozoic and Mesozoic limestone units. Detrital zircon work on Falher outcrops near Grand Cache Alberta, located approximately 175 km northwest of this study area, showed samples to represent provenance groups attributed to recycling from Paleozoic to Proterozoic aged passive-margin strata (Quinn et al. 2016). On a QpLvLs ternary diagram however, the samples of this study plot within the arc orogen provenance (Fig. 3.5D). This difference is due to the abundant percentage of volcanic detritus of volcanic rock fragments and feldspars within this studies samples (Table 3.2). Basal Falher sandstone intervals contain a greater proportion of volcanic grains relative to the upper Falher parasequence set outcrop equivalent Gates Formation sandstone, described by Leckie (1986), located approximately 350 km northwest of this study area in northeastern British Columbia (Fig. 3.5B). The difference is likely a result of a locus of volcanic activity in the southern portion of the cordillera during this time (Mellon, 1967), and the abundance of such detritus decreasing to the northwest with increasing axial drainage distances (Mellon, 1967; Jackson, 1984; Leckie and Smith, 1992). However, it should be noted that other Falher parasequence sets, between the examples shown herein, are of unknown lithology. Further, whether an abrupt or gradational transition from litharenite sandstone intervals which contain abundant volcanic detritus observed in this study, to mixed litharenite sandstone and pebble chert conglomerate intervals of upper Falher parasequence sets requires further research.

3.3.3 Paragenetic Sequence

Considerable porosity reduction occurred during diagenesis as a result of mechanical compaction, cementation and precipitation of authigenic clay minerals. This was observed through the examination of thin sections and scanning electron microscope images. A paragenetic sequence summary is shown in Figure 3.6, where relative timing and cause of diagenetic events largely came from literature review than observations. Porosity reduction through compaction is primarily a result of grain rearrangement, and plastic deformation of ductile grains.

58 Diagenetic Event Ferroan Quartz VRF & Depth Porosity (%) Mechanical Dolomite Overgrowth Feldspar (m) 40 20 0 Burial Compaction Cement Kaolinite Illite Cement Dissolution Chlorite 0

Shallow

1200

Moderate

3300

Deep

5000 Figure 3.6 - Paragenetic sequence based on literature review and petrographic observations on studied thin sections.

The high proportion of argillaceous sedimentary rock fragments and mica (muscovite, biotite, and detrital chlorite grains) in the samples, typically comprising over 20% of framework grains, led to significant porosity reduction by plastic deformation during mechanical compaction (Fig. 3.7A). Ferroan dolomite cement observed using dual carbonate staining, is present in most thin sections, and contributed significantly to porosity loss during early and moderate burial, contemporaneous with mechanical compaction (Fig. 3.7B & 3.8). Early ferroan dolomite cement, likely precipitated from formation waters with anomalously low δ18O ratios (Morad et al. 1996). While ferroan dolomite cement which precipitated later during moderate burial diagenesis, likely formed from an influx of Fe2+ from dissolution of volcanic rock fragments, as temperature increase during burial led to increases in the rate at which these chemical reactions takes place (Loucks et al. 1984; Kantorowicz, 1985; Morad 1998; Worden and Burly, 2003; Boggs, 2009). Kaolin was observed as stacked booklets along the c axis as a relatively highly ordered kaolinite polytype (Fig. 3.7C). The kaolin likely formed early from flushing of meteoric waters or together with organic acid-rich fluids, at the expense of feldspar dissolution, then transitioned to the

59 A B SRF SRF

Mica SRF SRF SRF

ferroan dolomite cement

1000 μm 1000 μm

C D

kaolinite polytype booklet

c axis

ab plane

E F

quartz Feldspar laths overgrowth VRF cement quartz grain Qtz Qtz cement

1000 μm 1000 μm

Figure 3.7 - Thin section and scanning electron microscope images of diagenetic features. A) Plastic deformation of ductile sedimentary rock fragment (SRF) and mica grains, 100x PPL (12-18-054-20 W5, 2953.1 m); B) early pore filling ferroan dolomite cement, 100x PPL (05-17-049-18 W5, 3199.1 m); C) pore filling ordered kaolin polytype booklets, yellow dashed line highlighting an example (08- 05-056-20 W5, 2817.2 m); D) pore filling illite crystallization (12-18-054-20 W5, 2951.2 m); E) quartz overgrowth cement on a quartz grain, 100x PPL (05-17-049-18 W5, 3203.3 m); F) partially dissolved volcanic rock fragment (VRF) and quartz overgrowth cement on a quartz grain, 100x PPL (12-18-054- 20 W5, 2949.7 m).

60 polytype observed due to increased temperature during burial (Lanson et al. 2002). Illite crystallization (Fig. 3.7D) of ordered kaolin likely occurred during deep burial with increased temperature or an increased K+/H+ activity ratio within an open system (Lanson et al. 2002). Quartz overgrowth cements (Fig. 3.7E & 3.7F), which were not point counted in this study; typically precipitate during shallow and moderate burial with excess silica, related to circulation of large volumes of water (Dutton and Diggs, 1990; Boggs, 2009). Quartz overgrowth cements are a major porosity reducing component within Spirit River Formation sandstone reservoirs, as also observed by Cant (1983), and Cant and Ethier (1984).

3.4 Discussion

3.4.1 Sequence Stratigraphy and Diagenetic Processes

Various grain fabrics can control reservoir quality within tight sandstone reservoirs. TIBCO Spotfire was used to observe preliminary cross-plot relationships of such grain fabrics to lab measured permeability (Fig. 3.8). Sandstone composed of rigid framework grains typically will undergo porosity reduction from 40 % to around 26 % through mechanical compaction alone; however, if malleable grains are present they can plastically deform to reduce porosity to 0% (Paxton et al. 2002). The percentages of malleable, ductile, grains of sedimentary rock fragments and mica within the studied sandstone intervals are high, commonly comprising over 20% of framework grains (Table 3.2). Ductile sedimentary rock fragments and mica grains are commonly observed to be plastically deformed into adjacent pore spaces (Fig. 3.7A), significantly reducing porosity. Thus, variations in the abundance of ductile grains and the rigidity of the sandstone, is a major control on porosity and thereby permeability.

Ferroan dolomite cement commonly precipitates during moderate burial depth diagenesis (Loucks et al. 1984; Kantorowicz, 1985; Morad 1998; Worden and Burly, 2003; Boggs, 2009); however it can also precipitate during early diagenesis (Machemer and Hutcheon, 1988; Bloch,

61 35 250 25 15 n = 7

30 210 20 12 r2 = 0.73 r2 = 0.72

Ductile grains (%)

25 170 Carbonate (%) 15 9 Mean long axis grain size (μm) 20 130 Chert grains (%) 10 6 r2 = 0.65

r2 = 0.11 15 90 5 3

10 50 0 0 0.001 0.01 0.1 Kl, slip-corrected permeability (mD) Figure 3.8 - Cross-plot data on grain fabrics, and composition against probe permeability, to decipher their likely influence on permeability.

1990; Morad et al. 1996). Even though early ferroan dolomite cement precipitates within open pores and thereby reduces porosity; the cement helps to create a rigid framework in pre-compacted sandstone. In the studied sandstone interval, ferroan dolomite cement observed in thin sections where adjacent sedimentary rock fragments show no significant deformation (Fig. 3.7B), and where ferroan dolomite cement accounts for a higher proportion of overall porosity loss, over 10 % (Fig. 3.9) is interpreted as early ferroan dolomite cement. An example of early ferroan dolomite cement observed in thin section from facies 5, shows significantly less porosity reduction due to mechanical compaction (Fig. 3.9). The abundance of ferroan dolomite cement is reflected in XRF data by slight increases in ferroan dolomite element weight percentages of Ca, Fe, Mn, and Sr, between a depth range of 3199.1 to 3199.8 m (Fig. 3.10B). Note this interval is associated with notably higher measured permeability values, likely due to the early rigid framework created which prevented significant plastic grain deformation.

There are five different processes that can cause early ferroan carbonate cementation,

often resulting in anomalously low δ18O values (Morad et al. 1996). The most likely process for early ferroan dolomite cementation in this study was from meteoric waters, due to the associ-

62 Ferroan Dolomite Cement (%) 0 10 20 30 40 40 0

20 30

Facies 5 0 Facies 4 20 Facies 3 50 Early ferroan dolomite cement ~60

Intergranular Porosity (%) 10 Intergranular Volume (%) Volume Intergranular

~85 Mechanical by Reduced Original Porosity No early ferroan

dolomite cement Solution (%) Pressure Compaction and Intergranular 0 100 0 50 100 Original Porosity Occluded by Ferroan Dolomite Cement (%) Figure 3.9 - Estimation of porosity reductions based on thin section point counts of ferroan dolomite cement percent, intergranular porosity numbers are from public core analysis data, inspired from Houseknecht, 1987. Note that quartz cementation is not included on figure due to cathodoluminescence petrography not being conducted but does contribute to porosity reduction. ation with early precipitation of kaolin and lack of sulfides observed (Machemer and Hutcheon, 1988). Previous studies within the Western Canada Foreland Basin have demonstrated early carbonate cements derived from meteoric water flushing using oxygen and carbon isotopic compositions (Machemer and Hutcheon, 1988; Bloch, 1990; Walz et al. 2012). The influence of invading meteoric water is far greater given the prolonged exposure within the meteoric water table during shoreline regression of the strongly progradational basal Falher parasequence sets (Loomis & Crossey, 1996; Morad et al. 2012), relative to the aggradational middle and upper Falher parasequence sets (Fig. 2.5 & Fig. 2.8A). This greater incursion of early meteoric water

63 within the basal Falher likely led to the slightly different eogenetic processes and overall paragenetic sequence compared with the upper Falher sandstone bodies, the latter described by Tilley and Longstaffe (1989).

Differences in residence time of shoreline deposits within the meteoric water table during regression, with minor relative-sea level rises and falls, and the presence of overlying transgressive marine mudstone or coals would likely influence diagenetic processes and could be deduced by examining the stratigraphic architecture of a succession. Further research is needed to determine what other sequence stratigraphic conditions may be related to enhanced reservoir quality, from the least damaging diagenetic effects, between and within each parasequence set sandstone reservoir in order to help identify and predict ‘sweet spots’.

3.4.2 Petrographic Responses

The objective of this section is to determine the cause for various petrographic responses of different facies, measured directly using lab equipment and observed geophysical well log responses, specifically the resistivity log.

Measured permeability values positively correlate well with grain size (Fig. 3.10A & B). The gradational upward increase in grain size from lower fine-grained sandstone (F4) to upper- fine-grained sandstone (F5) corresponds strongly with a gradational increase in permeability (Fig. 3.10A). As the grain size increase is gradational it shows that the facies are genetically related, where this specific interval is interpreted as a high-energy, non-barred shoreline deposited during relatively calmer periods (Clifton et al. 1971; Clifton, 2006). Associated with this vertical increase in permeability and grain size, is an increase in resistivity log readings (Fig. 3.10).

Finer grain sizes and thereby smaller pore throat sizes, have been shown to be related to higher capillary pressure and irreducible water saturation, which increases conductivity (Kieke and Hartmann, 1974; Vajnar et al. 1977; Wardlaw and Cassan, 1979; Heckel, 1985; Worthington, 2000; Nelson, 2009). Where permeability trends positively correlate with resistivity log read-

64 A) 3255.4

3257.4 1 F5

3261.4

3265.4 F4

3269.4 3 F3

3273.4 F P VF M C Gr Depth VC Facies 0.001 0.01 0.1 1 0 25 0 10 10 100 Mud Silt Sand Gravel 2620 2660 2700 2740 2780 (m) kl (mD) & Grain Den. (kg/m^3) Ca wt. % Fe wt. % Deep Resistivity (ohm m) B) 3195.0

3199.0 F5 1 early ferroan dolomite cement

3203.02 3

3207.0

3209.0 F P VF M C VC Depth Gr Facies 0.001 0.01 0.1 1 0 25/10 0 0.2 10 100 Mud Silt Sand Gravel 2620 2660 2700 2740 2780 (m) kl (mD) Grain Den. (kg/m^3) Ca wt. % Fe wt. % Mn / Sr wt. % Deep Resistivity (ohm m) C) 3148.0

3152.1

3156.1

F4 3160.1 F P VF M C VC Depth Gr Facies 0.001 0.01 0.1 1 0 25/10 0 0.2 10 100 Mud Silt Sand Gravel 2620 2660 2700 2740 2780 (m) kl (mD) Grain Den. (kg/m^3) Ca wt. % Fe wt. % Mn / Sr wt. % Deep Resistivity (ohm m) Figure 3.10 - Vertical plots showing trends between various petrographic measurements. A) 13-34- 046-16 W5 in Falher O, depth range 3255.4 to 3273.4 m. B) 05-17-049-18 W5 in Falher N, depth range 3195.0 to 3209.0 m C) 13-29-046-15 W5 in Falher O, depth range 3149.0 to 3160.1 m. Purple diamonds are slip-corrected permeability values collected using PDPK. Green circles are grain density values from GeoSCOUT, and black squares were collected on core plugs using He-Pycnometer.

65 ings suggests grain size and thereby pore throat size, are strongly influencing the resistivity log readings. The increase in resistivity log readings from facies 4 to facies 5 therefore likely reflects a decrease in capillary pressure and irreducible water saturation. This also could indicate a possible transition from non-effective porosity, microporosity, within the finer grained facies, to effective macroporosity within facies 5 (Worthington, 2000).

Facies 3 consists of very fine-grained sandstone (Table 3.1 & Fig. 3.3), and shows an increase in resistivity log readings corresponding with the lowest measured permeability values (Fig. 3.10A). If irreducible water saturation and capillarity principally controlled resistivity throughout the sandstone beds, then intervals with the lowest permeability values would have the lowest resistivity readings from increased conductivity. However, sandstone intervals of F3 which have the lower permeability values, a function of the very fine grain size and increased cementation, have higher resistivity log readings (Fig. 3.10A). This suggests low pore connec- tivity and a more tortuous pore network and thereby fewer conductive pathways, resulting in a higher formation resistivity factor (Archie, 1942). Further, the anomalously high resistivity log readings which correspond to the lowest permeability, are likely also strongly related to mineralogy, where the highly ferroan dolomite cemented sandstone has such a high formation resistivity factor that the resistivity log is reflecting ‘tightness’ (Fig. 3.10A & C). This effect is therefore overprinting the minor change in capillary pressure differences within pores.

Further suppression of the resistivity log within facies 4 is possible due to a slight increase in abundance of conductive elements; mainly iron (Fig. 3.10). The latter is reflected by an increase in grain density (Fig. 3.10), corresponding with the higher content of higher grain density iron-bearing minerals. From thin section observations, the higher abundance of minerals within F4 of greater grain density includes volcanic rock fragments, detrital carbonate grains, ferroan dolomite cement and authigenic illite (Table 3.2).

The amount of clay wt. % percentage does not change significantly within the clean sandstone interval (Fig. 2.6 & 3.9). The sandstone interval is positioned below the gas-water

66 contact in the Alberta Deep Basin, therefore the interval is likely entirely gas charged and has relative uniform hydrocarbon saturation (Masters, 1979; Gies, 1984). Thus, changes in clay content and hydrocarbon saturation within the sandstone intervals are not suggested to change significantly and be factors impacting resistivity log readings.

Overall it is shown that petrographic responses for ‘Wilrich’ sandstone reflect both the petrology of the rocks, such as mineralogy and pore throat size, and the fluids, such as irreducible water saturation. Thus, to interpret petrographic responses for the ‘Wilrich’, one needs to incorporate as much data as possible while looking at overall trends, and to not attempt cross- plot correlations with lab measured variables without thin section observations.

3.5 Conclusions

Petrographic and thin section analysis documented the overall grain texture, mineralogy, provenance, and a paragenetic summary for the fine-grained sandstone of the petroleum industry referred ‘Wilrich’. As well, such observations were used to investigate lab measured petrographic data and resistivity log readings trends. The following are the main conclusions:

1. Grain size distributions of facies within shoreline parasequence sets demonstrate the coarsening upwards of very fine- to upper fine-grained sandstone.

2. Basal Falher shoreline sandstone bodies contain a strong mixture of western thrust belt derived sediments of mechanically unstable lithic fragments, and chert grains derived from older Paleozoic and Mesozoic limestone. As well as an abundant volcanic detritus input, derived from a locus of volcanic activity in the southern portion of the cordillera.

3. Significant porosity reduction has occurred during diagenesis as a result of mechanical compaction through grain rearrangement and plastic deformation, precipitation offer roan dolomite cement and quartz overgrowth cement on quartz grains, and precipitation

67 of authigenic clay minerals.

4. A more rigid grain framework created from early ferroan dolomite cement precipitation, due to prolonged exposure within the meteoric water table during shoreline regression of the strongly progradational basal Falher parasequence sets, reduced the effects of plastic deformation of ductile grains, and increased reservoir quality.

5. Increases in resistivity logs correspond to decreases in both capillary pressure and irreducible water saturation. High resistivity anomalies occur where intervals are so heavily cemented with ferroan dolomite that the resultant increase in the formation resistivity factor over prints any capillary pressure variation.

3.6 References Archie, G.E., 1942, The electrical resistivity log as an aid in determining some reservoir characteristics: Transactions of the American Institute of Mining, Metallurgical and Petroleum Engi- neers, v. 146, p. 54-62. Bloch, J., 1990, Stable isotopic composition of authigenic carbonates from the Albian Harmon Member (Peace River Formation): evidence of early diagenetic processes: Bulletin of Canadian Petroleum Geology, v. 38, p. 39-52. Boggs, S., Jr., 2009, Petrology of sedimentary rocks: Cambridge University Press, New York, 600 p. Cant, D.J., 1983, Spirit River Formation – A stratigraphic-diagenetic gas trap in the Deep Basin of Alberta: AAPG Bulletin, v. 67, p. 577-587. Cant, D.J., and Ethier, V.G., 1984, Lithology-dependent diagenetic control of reservoir properties of conglomerates, Falher Member, Elmworth Field, Alberta: AAPG Bulletin, v. 68, p. 1044-1054. Clifton, H.E., 2006, A reexamination of facies models for clastic shorelines, in Posamentier, H.W., and Walker, R.G., eds., Facies Models Revisited: SEPM Special Publication 84, p. 293-337. Clifton, H.E., Hunter, R.E., and Phillips, R.L., 1971, Depositional structures and processes in the non-barred high-energy nearshore: Journal of Sedimentary Petrology, v. 41, p. 651-670. Dickinson, W.R., 1970, Interpreting detrital modes of greywacke and arkose: Journal of Sedimen- tary Petrology, v. 40, p. 695-707. Dickinson, W.R., and Suczek, C.A., 1979, Plate tectonics and sandstone compositions: AAPG Bul-

68 letin, v. 63, p. 2164-2182. Dutton, S.P., and Diggs, T.N., 1990, History of quartz cementation in the Lower Cretaceous Travis Peak Formation, east Texas: Journal of Sedimentary Petrology, v. 60, p. 191-202. Folk, R.L., 1974, Petrology of sedimentary rocks: Hemphill Publishing Co., Austin, Texas, 170 p. Gies, R.M., 1984, Case history for a major Alberta Deep Basin gas trap: the Cadomin Formation, in Master, J.A., ed., Elmworth – Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 115-140. Heckel, B.H., 1985, Enhanced hydrocarbon recognition – a new approach to well evaluation for sand - shale sequences: Annual Technical Meeting, June 2 – 5, Edmonton Alberta. Houseknecht, D.W., 1987, Assessing the relative importance of compaction processes and cementation to reduction of porosity in sandstones: AAPG Bulletin, v. 71, p. 633-642. Jackson, P.C., 1984, Paleogeography of the Lower Cretaceous Mannville Group of western Cana- da, in Masters, J.A., ed., Elmworth: Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 49-77. Jones, S.C., 1994, A new, fast, accurate pressure-decay probe permeameter: Society of Petro- leum Engineers Formation Evaluation, v. 9, p. 193-199. Kantorowicz, J.D., 1985, The origin of authigenic ankerite from the Ninian Field, UK North Sea: Nature, v. 315, p. 214-216. Kieke, E.M., and Hartmann, D.J., 1974, Detecting microporosity to improve formation evaluation: Journal of Petroleum Technology, v. 26, p. 1080-1086. Lanson, B., Beaufort, D., Berger, G., Bauer, A., Cassagnabère, A., and Meunier, A., 2002, Authi- genic kaolin and illitic minerals during burial diagenesis of sandstones: a review: Clay Minerals, v. 37, p. 1-22. Leckie, D.A., 1986, Petrology and tectonic significance of Gates Formation (Early Cretaceous) sediments in northeast British Columbia: Canadian Journal of Earth Sciences, v. 23, p. 129-141. Leckie, D.A., and Smith, D.G., 1992, Regional setting, evolution and depositional cycles of the Western Canada foreland basin, in Macqueen, R.W., and Leckie, D.A., eds., Foreland basins and Fold Belts: American Association of Petroleum Geologists Memoir 55, p. 9-46. Loomis, J.L., and Crossey, L.J., 1996, Diagenesis in a cyclic, regressive siliciclastic sequence: the Point Lookout Sandstone, San Juan Basin, Colorado, in Crossey, L.J., Loucks, R., and Totten, M.W., eds., Siliciclastic Diagenesis and Fluid Flow: Concepts and Applications: SEPM Special Publication 55, p. 23-36. Loucks, R.G., Dodge, M.M., and Galloway, W.E., 1984, Regional controls on diagenesis and reservoir quality in Lower Tertiary sandstones along the Texas Gulf Coast, in MacDonald, D.A., and Surdam, R.C., eds., Clastic diagenesis: American Association of Petroleum Geologists Memoir 37, p. 15-36.

69 Machemer, S.D., and Hutcheon, I., 1988, Geochemistry of early carbonate cements in the Cardi- um Formation, central Alberta: Journal of Sedimentary Petrology, v. 58, p. 136-147. Masters, J.A., 1979, Deep Basin gas trap, western Canada: AAPG Bulletin, v. 63, p. 152-181. Mellon, G.B, 1967, Stratigraphy and petrology of the Lower Cretaceous Blairmore and Mannville groups, Alberta foothills and plains: Research Council of Alberta, Bulletin 21, 270p. Morad, S., 1998, Carbonate cementation in sandstones: distribution patterns and geochemical evolution, in Morad, S., ed., Carbonate cementation in Sandstones: International Association of Sedimentologists Special Publication 26, p. 1-26. Morad, S., De Ros, L.F., and Al-Aasm, I.S., 1996, Origin of low δ18O, pre-compactional ferroan carbonates in the marine Stø Formation (Middle Jurassic), offshore NW Norway: Marine and Petroleum Geology, v. 13, p. 263-276. Morad, S., Ketzer, J.M., and De Ros., L.F., 2012, Linking diagenesis to sequence stratigraphy: an integrated tool for understanding and predicting reservoir quality distribution, in Morad, S., Ketzer, J.M., and De Ros, L.F., eds., Linking Diagenesis to Sequence Stratigraphy: International Association of Sedimentologists, Special Publication 45, p. 337-352. Nelson, P.H., 2009, Pore-throat sizes in sandstones, tight sandstones, and shales: AAPG Bulletin, v. 3, p. 329-340. Paxton, S.T., Szabo, J.O., Ajdukiewicz, J.M., and Klimentidis, R.E., 2002, Construction of an intergranular volume compaction curve for evaluating and predicting compaction and porosity loss in rigid-grain sandstone reservoirs: AAPG Bulletin, v. 86, p. 2047-2067. Quinn, G.M., Hubbard, S.M., van Drecht, R., Guest, B., Matthews, W.A., and Hadlari, T., 2016, Record of orogenic cyclicity in the Alberta foreland basin, Canadian Cordillera: Lithosphere, v. 8, p. 317-332. Tilley, B.J., and Longstaffe, F.J., 1989, Diagenesis and isotopic evolution of porewaters in the Alberta Deep Basin: the Falher Member and Cadomin Formation: Geochimica et Cosmochimica Acta, v. 53, p. 2529-2546. Vajnar, E.A., Kidwell, C.M., and Haley, R.A., 1977, Surprising productivity from low-resistivity sands: Transactions of the 18th SPWLA Annual Logging Symposium, EE1-11. Walz, C., Chi, G., and Pedersen, P.K., 2012, Petrographic, stable isotope and fluid inclusion characteristics of the Viking sandstones: implications for sequence stratigraphy, Bayhurst area, SW Saskatchewan, Canada, in Morad, S., Ketzer, J.M., and De Ros, L.F., eds., Linking Diagenesis to Sequence Stratigraphy: International Association of Sedimentologists, Special Publication 45, p. 337-352. Wardlaw, N.C., and Cassan, J.P., 1979, Oil recovery efficiency and the rock-pore properties of some sandstone reservoirs: Bulletin of Canadian Petroleum Geology, v. 27, p. 117-138. Wentworth, C.K., 1922, A scale of grade and class terms for clastic sediments: The Journal of Geology, v. 30, p. 377-392.

70 Worden, R.H., and Burley, S.D., 2003, Sandstone diagenesis: the evolution of sand to stone, in Burley S.D., and Worden, R.H., Sandstones Diagenesis: Recent and Ancient. International Associ- ation of Sedimentologists, Blackwell Publishing Ltd., Oxford, p. 3-44. Worthington, P.F., 2000, Recognition and evaluation of low-resistivity pay: Petroleum Geosci- ence, v. 6, p. 77-92.

71 Chapter Four: Conclusions

4.1 Summary

The basal progradational Falher, ‘Wilrich’, is an emerging Alberta Deep Basin liquid rich gas resource play, which has been exploited by multi stage hydraulic fractured horizontal wells since the late 2000’s. Horizontal well targets laterally extensive fine-grained dissipative shorelines and less commonly laterally confined fluvial sandstone intervals. Research in this thesis addresses the under studied basal interval of the Spirit River Formation by facies mapping and correlations revealing an unique progradation changing to aggradational stratigraphic architecture of the clastic wedge. As well, an evaluation of mineralogy, grain textures, and diagenetic events was undertaken to investigate permeability and associated resistivity log response variations within the thick relatively uniform sandstone intervals.

The Early Cretaceous Spirit River Formation in west-central Alberta was deposited within a shallow epeiric sea and prograded axially northward as approximately east-west trending wave-dominated deltaic shorelines, following the maximum transgression of the Moosebar Sea. In the subsurface study area (T46 to T58 and R13 W5 to R1 W6), the studied succession consists of five 10 to 25 m thick coarsening upwards shoreline sandstone and conglomerate, that form northward accreting parasequence sets, which display a very strongly progradational to slightly aggradational stacking pattern (Fig. 2.8A). Falher unit names were assigned to parasequence sets, which are bounded by mappable major marine-flooding surfaces, following recent stratigraphic nomenclature established for older Falher shoreline trends (Zonneveld and Moslow, 2004). Mudstone deposits of the Wilrich Member and non-marine strata of the Upper Mann- ville undifferentiated were treated as coeval units within the sequence stratigraphic framework.

The basal progradational Falher shorelines have broad lateral continuous facies belts, but show lateral variations in along shore facies and architecture. The shorelines are commonly sharp-based, reflecting the shorelines prograded into shallow water depths with seafloor re-

72 maining above storm wave base, with a relatively shallow to flat subaqueous profile. Shallow water depths and continuous storm influence led to broad facies belts with interbedded mudstone and sandstone beds of offshore transition facies 2 being deposited farther seaward due to continuous sea floor agitation in the shoreline proximal areas (Fig. 2.11). Further, the high wave energy caused an absence of F2 deposits in proximal areas due to erosion rates being greater than sedimentation rates, resulting in the observed sharp-based shoreline. Detailed mapping and multiple, parallel depositional-strike orientated cross-sections of the Falher N parasequence set were used to highlight the offshore facies architecture (Fig. 2.9). The cross-sections revealed a shallower gradient, together with more abundant storm sandstone deposits, on the eastern side of the shoreline compared to the western side, suggesting offshore geostrophic currents played a significant role in offshore facies distributions (Fig. 2.12). The work within this thesis demonstrates the importance of sedimentology and mapping in stratigraphic correlations and is applicable to investigations of other ancient shoreline sequences deposited in shallow epeiric seas elsewhere.

Reservoir characterization investigated the controls on permeability and the cause of unique resistivity log responses, utilizing the facies and sequence stratigraphic framework established in chapter two. The dominantly fine-grained sandstone to mixed conglomeratic wave-dominated upper shoreface facies has the highest permeability, controlled by the larger grain size and thereby pore throat size. Several diagenetic processes were observed to decrease permeability; specifically compaction was shown to be a more significant porosity reducer than cementation (Fig. 3.9). An example of increased permeability was highlighted where early ferroan dolomite cement created a more rigid early framework which hindered the effects of ductile grains being squeezed into adjacent pore spaces by mechanical compaction. Early meteoric water flushing is interpreted to have caused the precipitation of this cement, which is likely a result of prolonged exposure within the meteoric water table due to the strongly progradational nature of the parasequence sets (Fig. 2.8A). Petrographic responses such as permeability and grain density generally correlate to grain size, with permeability increasing with greater grain

73 size and grain density decreasing with greater grain size (Fig. 3.10). While increases in resistivity log responses correspond to decreases in both capillary pressure and irreducible water saturation, high resistivity anomalies occur demonstrating the highly mineralogically and diagenetic altered sandstone to increased tightness and formation resistivity factor. The work within this portion of the thesis demonstrates the importance of thin section observations when interpreting petrographic data.

4.2 Future Work

The regional stratigraphic framework established for the Spirit River Formation within this thesis aided in accurately portraying Upper Mannville stratigraphy in subsurface west-central Alberta (Fig. 2.5). Throughout the basin, Upper Mannville stratigraphy has inconsistent stratigraphic nomenclature. Insights from work within this thesis will aid in establishing a uniform basin-wide Upper Mannville stratigraphic nomenclature in the future.

Recommendations for western subsurface Upper Mannville stratigraphic nomenclature include: 1) continue lettered Falher unit names for each 10 to 25 m thick, sandstone and conglomerate shoreline parasequence set, until the Hoadley Barrier; 2) include all dominantly marine mudstone deposits, which are correlative to individual shorelines, as part of the Wilrich Member; 3) subdivide the Spirit River Formation into Upper and Lower formations representing two separate depositional sequences, if a significant sequence boundary and mineralogy change is proven across the transition of the different stacking patterns; 4) integrate the Glauc- onitic / Bluesky Formation stratigraphic interval as the oldest depositional sequence within this sequence set, which includes the overlying Spirit River Formation clastic wedge.

Reservoir quality through measured permeability was investigated by petrologic thin section observations within this thesis. However, other factors such as reservoir pressure can be vital for enhanced production within tight unconventional sandstone reservoirs (Law, 2002).

74 The here demonstrated sequence stratigraphic architecture of the basal Falher shorelines (Fig. 2.8A), are comprised of individual sheet-like sands bodies (Fig. 2.8B), separated by lateral continuous mudstone could suggest each parasequence set likely has its own reservoir properties, including reservoir pressure and hydrocarbon fluid charge. Within the Alberta Deep Basin units dip towards the west and gas leakage to higher porosity sandstone updip to the east is common (Masters, 1984). A greater lateral updip extent of the shoreline sandstone to higher porosity water-saturated sandstone may lead to more gas leakage and pressure depletion. Further, the top seal on each parasequence set varies between thin and thick coals and marine mudstone. Detailed mapping of the shoreline sandstone updip as well as the thickness and lateral extent of seals overlying parasequence sets, together with reservoir pressure data could provide additional insights into the variable production trends within the ‘Wilrich’ (Fig. 3.1). The importance of reliable reservoir pressure data would be crucial for such an undertaking.

4.3 References Law, B.E., 2002, Basin-centered gas system: AAPG Bulletin, v. 86, p. 1891-1919. Masters, J.A., 1984, Lower Cretaceous oil and gas in western Canada, in Master, J.A., ed., El- mworth – Case study of a deep basin gas field: American Association of Petroleum Geologists Memoir 38, p. 1-34. Zonneveld, J.-P., and Moslow, T.F., 2004, Exploration potential of the Falher G shoreface conglomerate trend: evidence from outcrop: Bulletin of Canadian Petroleum Geology, v. 52, no. 1, p. 23-38.

75 Appendix: Logged Cores

Physical Sedimentary Structures Trace Fossils - low angle planar laminations - root traces - trough cross-stratification - cryptic bioturbation - fugichnia - swaley cross-stratification - Arenicolites - hummocky cross-stratification - Asterosoma - wave ripple lamination - Chondrites - current ripple lamination - Cylindrichnus - starved current ripple - Diplocraterion - climbing ripples - Gyrolithes - wavy laminations - Helminthopsis - normal graded bedding - Macaronichnus - soft sediment deformation - Ophiomorpha Organic Remains - Palaeophycus - carbonaceous laminae - Phycosiphon - Planolites - coal clasts / debris - Rhizocorallium - leaf imprints - Rosselia Lithology - Teichichnus - coal - Thalassinoides - mudstone - siltstone - sandstone - clast supported conglomerate # - thin section location - scattered pebbles - mud rip up clasts - bentonite layer

76 13-29-046-15 W5

3148.00m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Transgressive Unit (API) OHM*M F0 Surface Shoreline 0 75 150 1 10 100 1000 mFS 1 F6

3150.0 Foreshore mFS 1

3160.0 Falher O Falher Spirit River Formation Spirit River 3152.10m 3170.0 F5 mFS 0

Proximal Nearshore

3156.10m

Middle F4 Shoreface

3160.10m Depth (m) Interpreted F P VF M C Physical Biogenic

VC Facies Mud Gr & Strat. Silt Depositional Sand Gravel Sedimentary Structures Association Surface Environment

77 06-27-046-16 W5

3323.5 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3320.0

3325.5 m mFS 1

3330.0

Proximal F5 Nearshore Falher N Falher

Spirit River Formation Spirit River 3340.0

mFS 0

3350.0

3329.5 m O Falher

3333.5 m

Middle F4 Shoreface

3337.5 m

3341.5 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

78 13-34-046-16 W5

3255.40m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

mFS 1 3257.40m Upper F5 Shoreface 3260.0

1 Falher O Falher

3270.0 Spirit River Formation Spirit River

mFS 0

3261.40m

Middle F4 Shoreface 3265.40m 3

3269.40m

Lower Shoreface F3

3273.40m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

79 13-35-046-18 W5

3457.60m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000 ?? ?? ? 3460.0

3459.60m Upper Mannville 3470.0

Falher O Falher 3480.0

Deltaic Formation Spirit River Distributary Channels 3490.0 F8

3463.60m mFS 0

Interdistribu- tary Bay / Lagoon

3467.60m Coastal Plain F6

Foreshore

Upper 3471.60m Shoreface

3475.60m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

80 10-02-047-15 W5

3027.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

Transgressive F0 Shoreline

3030.0 mFS 1 F1 mFS 1 3030.0 m

3040.0 Falher O Falher Spirit River Formation Spirit River

3050.0 Wilrich 3060.0 Proximal 3034.0 m F5 Nearshore

3038.15 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

81 01-28-048-18 W5

3215.00 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Non-Marine Unit (API) OHM*M F6 Surface Coastal Plain 0 75 150 1 10 100 1000

3205.0

Foreshore Falher L Falher mFS 2 3215.0

3219.00 m

3225.0 Falher N Falher F5 Formation Spirit River

3235.0

Upper mFS 1 Shoreface

3223.00 m

3227.00 m

Middle F4 Shoreface

3231.00 m

3233.85 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

82 05-17-049-18 W5

Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3 3180.0

3203.0 m

4 3190.0 Falher L Falher mFS 2

3200.0 Spirit River Formation Spirit River Middle 3210.0 Shoreface F4 N Falher 3207.0 m

mFS 1 3220.0 Falher O Falher

3192.0 m mFS 2 F0

Transgressive 3211.0 m Shoreline F1

Non-Marine Coastal Plain F6

3195.0 m 5

Foreshore

3215.0 m 1

Lower F3 Shoreface F5

3199.0 m 2 Upper Shoreface

3219.1 m Depth (m) Interpreted Depth (m) Interpreted F F P P VF M C Physical Biogenic VF M C Physical Biogenic VC VC Mud Gr Mud Gr & Strat. Silt Depositional Facies & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Sand Gravel Sedimentary Structures Surface Environment Surface Environment

83 01-05-049-19 W5

3276.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic Transgressive (API) & Strat. OHM*M F1 Unit Shoreline 0 75 150 Surface 1 10 100 1000

3278.0 m Foreshore 1 3270.0 Falher L Falher mFS 3

3280.0 2

Upper 3290.0 3 F5 Formation Spirit River Shoreface Falher N Falher

3282.0 m

3300.0

mFS 1

3286.0 m

Middle F4 Shoreface

3290.0 m

6 3294.05 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

84 07-17-049-19 W5

3278.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3260.0 Upper Mannville

3270.0

3281.6 m L Falher mFS 3 Low Energy F7 Shoreline

3280.0 Spirit River Formation Spirit River Falher M Falher

mFS 2 3290.0

3285.6 m Falher N Falher 3300.0

3289.6 m

Transgressive F0 Shoreline

mFS 3 Coastal Plain F6 3293.6 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

85 02-16-050-20 W5

3197.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic Oﬀshore & Strat. F2 Unit (API) OHM*M Transition 0 75 150 Surface 1 10 100 1000

3199.0 m F0 3200.0

Transgressive L Falher mFS 3 Shoreline mFS 3

F1 3210.0

Falher M Falher FS

3220.0 Spirit River Formation Spirit River 3203.0 m mFS 2

Interdis- N Falher tribtary and F8 2 Deltaic Distributary Channels 3

3207.0 m

Middle F4 Shoreface

3211.0 m

4 Lower F3 Shoreface

FS Transgressive F0 Deposits Lower F3 Shoreface 3215.0 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

86 14-18-050-21 W5

3435.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3430.0

3437.0 m Stacked Fluvial Channels

Upper Mannville 3440.0

3450.0 Falher L Falher

Spirit River Formation Spirit River mFS 3 3441.0 m Coastal Plain 3460.0 Falher M Falher 3470.0

3445.0 m

Low Energy F7 Shoreline

3449.0 m

3453.0 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

87 14-20-050-21 W5

3366.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3360.0 3368.0 m

3370.0

3380.0 Spirit River Formation Spirit River Upper Mannville Undiﬀerentiated Upper Mannville

3372.0 m 3390.0

Stacked Non-Marine F6 Fluvial 3400.0 Channels mFS 2 Falher N Falher

3376.0 m

3380.0 m

3384.0 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

88 2676.60 m 2656.60 m

Lower F3 Shoreface

2680.60 m 2660.60 m

Middle F4 Shoreface

Oﬀshore F2 Transition

F0 FS 2684.60 m 2664.60 m Lower F3 Shoreface

Lower F3 Shoreface

2688.60 m 2668.60 m Transgressive Shoreline F0

mFS 2

mFS 1? Middle F4 Shoreface

Oﬀshore F2 Transition

2692.60 m 2672.60 m Lower F3 Shoreface

Oﬀshore F2 Transition

2696.60 m mnFS F0 Depth (m) Interpreted Depth (m) Interpreted F F P VF M C P VF M C Physical Biogenic Physical Biogenic VC VC Gr Mud Gr Mud Silt & Strat. Silt Depositional Facies & Strat. Depositional Facies Sand Gravel Sedimentary Structures Sand Gravel Sedimentary Structures Surface Environment Surface Environment

89 01-21-051-17 W5

2643.00 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000 2644.60 m

2650 m Falher L Falher mFS 3

Low Energy 2660 m Shoreline F7 Falher M Falher

2670 m

2648.60 m Spirit River Formation Spirit River mFS 2

2680 m

Falher N Falher FS

mFS 1? 2690 m

Transgressive Shoreline F0 Wilrich mFS 3 2700 m

2652.60 m Foreshore

Upper Shoreface

Depth (m) Interpreted F P VF M C Physical Biogenic

VC Facies Mud Gr & Strat. Silt Depositional Sand Gravel Sedimentary Structures Association Surface Environment

90 2788.00

Oﬀshore F2 Transition

2771.00 2792.00

Transgressive Low Energy F7 Shoreline F0 Shoreline

Transgressive mFS 2 Shoreline F0 mFS 3

Lower F3 Shoreface Foreshore 2796.00 2776.00

F0 FS F5

Lower F3 Shoreface Upper Shoreface

2800.00 2780.00

Oﬀshore F2 Transition

2804.00 2784.00 Middle Shoreface F4 Zoo?

Transgressive F0 Shoreline mFS 1 Lower Lower F3 Shoreface Shoreface F3

2807.26 Depth (m) Interpreted Depth (m) Interpreted F F P VF M C P VF M C Physical Biogenic Physical Biogenic VC VC Gr Mud Gr Mud Silt & Strat. Silt Depositional Facies & Strat. Depositional Facies Sand Gravel Sedimentary Structures Sand Gravel Sedimentary Structures Surface Environment Surface Environment

91 16-03-051-18 W5

Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

2770 m Falher L Falher mFS 3 2780 m

Falher M Falher 2790 m

mFS 2

2800 m FS Falher N Falher Spirit River Formation Spirit River mFS 1

2810 m Wilrich 2820 m

92 04-22-053-16 W5

2424.5 m Transgressive Gamma Ray Depth (m) Deep Resistivity F0 Stratigraphic Shoreline & Strat. mFS 3 Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

2426.5 m 2410.0 Falher L Falher

2420.0

mFS 3

2430.0 Spirit River Formation Spirit River

2430.5 m

2440.0 Insiced F9 Channel mFS 2 Falher N Falher

2434.5 m

2438.5 m

Transgressive Shoreline F0

mFS 2 Oﬀshore F2 Transition 2442.85 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

93 10-26-053-16 W5

2364.50 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M Surface 1 10 Transgressive 0 75 150 100 1000 F0 Shoreline

2360 m Falher L Falher Oﬀshore F2 2367.10 m Transition 2370 m mFS 3 mFS 3

Transgressive Shoreline F1 Spirit River Formation Spirit River 2380 m ????

2390 m

2371.10 m

2375.10 m Insiced Channel F9

2379.10 m

2383.10 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

94 12-18-054-20 W5

2947.50 m Gamma Ray Deep Resistivity Stratigraphic Depth (m) Foreshore Unit (API) & Strat. OHM*M 0 75 150 Surface 1 10 100 1000

2949.00 m F5

1 Upper 2850.0 Shoreface Falher K Falher Spirit River Fm Spirit River

mFS 4

2953.00 m 2 Middle F4 Shoreface

2957.00 m

Lower F3 3 Shoreface

2961.00 m

Transgressive F0 Shoreline 2965.50 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

95 13-17-054-20 W5

2907.50 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M Non-Marine 0 75 150 Surface 1 10 100 1000 Coastal F6 Plain 2910.0

2909.70 m

Foreshore 2920.0 Falher K Falher

2930.0

F5 Formation Spirit River mFS 4

2940.0 Upper 2913.70 m Shoreface Falher L Falher

2917.70 m

Middle F4 Shoreface

2921.70 m

Lower F3 Shoreface

2925.70 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

96 02-25-054-21 W5

2910.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic (API) & Strat. OHM*M Foreshore Unit 0 75 150 Surface 1 10 100 1000

2912.0 m F5 2905.0

Upper Shoreface 2915.0 Falher K Falher

Spirit River Formation Spirit River 2925.0 mFS 4

2916.0 m

2935.0 Falher L Falher

Middle F4 Shoreface

2920.0 m

Lower F3 Shoreface

2924.0 m

2928.0 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

97 3023.5 m Non-Marine & Coastal Plain F6 3044.0 m

Transgressive F0 Shoreline

Interdistribu- F8 tary Bay & Lagoon mFS 4 3048.0 m 3028.0 m

3052.0 m 3032.0 m Middle F4 Shoreface Proximal F5 Nearshore

3056.0 m 3036.0 m

Middle F4 Shoreface

3060.0 m 3040.0 m

Lower F3 Shoreface

3064.15 m 3044.0 m Depth (m) Interpreted Depth (m) Interpreted F F P P VF M C Physical Biogenic VF M C Physical Biogenic VC VC Gr Mud Mud Gr Silt & Strat. Depositional Facies & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Sand Gravel Sedimentary Structures Surface Environment Surface Environment

98 14-18-054-22 W5

Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000

3030.0

Falher K Falher 3040.0

mFS 4 3050.0 Spirit River Formation Spirit River

Falher L Falher 3060.0

3070.0 mFS 3

Falher M Falher 3080.0

99 01-35-055-23 W5

3019.20 m Gamma Ray Deep Resistivity Stratigraphic Depth (m) (API) & Strat. OHM*M Non-Marine F6 Unit Coastal Plain 0 75 150 Surface 1 10 100 1000

Foreshore 3025.0 1 F5

3023.00 m Spirit River Formation Spirit River Falher K Falher Proximal Nearshore

mFS 4 3050.0

3027.00 m

Middle F4 Shoreface

3031.00 m

3035.00 m 4

Lower F3 Shoreface

3037.40 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

100 01-25-055-26 W5

3478.00m F6 Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M Surface Foreshore 0 75 150 1 10 100 1000

3480 m 3480.00m F5

Proximal Neashore 3490 m Falher K Falher

Spirit River Formation Spirit River 3500 m

mFS 3

3484.00m

3488.00m Middle & Lower F4 & F3 Shoreface

3492.00m

Transgressive F0 Shoreline 3496.00m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

101 2140.0 m 2120.0 m

Foreshore

Middle F4 Shoreface

Upper F5 Shoreface 2144.0 m 2124.0 m

2148.0 m 2128.0 m

Transgressive F0 Shoreline 2152.0 m 2132.0 m

Middle F4 Shoreface

2156.0 m 2136.0 m Transgressive F0 Deposits

2159.6 m Depth (m) Interpreted Depth (m) Interpreted F F P VF M C Physical Biogenic VC P VF M C Biogenic

Physical Gr VC Mud Gr Mud Silt & Strat. Silt Depositional Facies & Strat. Depositional Facies Sand Gravel Sedimentary Structures Sand Gravel Sedimentary Structures Surface Environment Surface Environment

102 04-04-056-16 W5

2112.0 m Gamma Ray Depth (m) Deep Resistivity Stratigraphic & Strat. Unit (API) OHM*M 0 75 150 Surface 1 10 100 1000 2110.0

2120.0

Non-marine & Coastal F6 Plain 2130.0 2116.0 m Falher K Falher 2140.0

2150.0 mFS 4 Spirit River Formation Spirit River

Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies 2160.0 Sand Gravel Sedimentary Structures Surface Environment Falher L Falher

2170.0

103 02/10-13-056-19 W5

2538.0 m Stratigraphic Gamma Ray Depth (m) Deep Resistivity Unit (API) & Strat. OHM*M 0 75 150 Surface 1 10 100 1000 2539.0 m

2540.0

Proximal Nearshore

2550.0 Falher K Falher

2560.0 Spirit River Fm Spirit River

2543.0 m mFS 4

Upper Shoreface

2547.0 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

104 02/08-05-056-20 W5

2811.00 m Gamma Ray Foreshore Stratigraphic Depth (m) Neutron Porosity (%) & Strat. Unit (API) Density Porosity (%) 0 75 150 Surface 45 30 15 0 -15

2813.00 m 2775.0 1 Upper Shoreface F5 Falher K Falher Spirit River Fm Spirit River

mFS 4 2800.0

2817.00 m 2

2821.00 m 3 Middle Shoreface F4

2825.00 m

Lower Shoreface F3

2828.90 m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

105 07-18-057-24 W5

2899.00m Gamma Ray Depth (m) Deep Resistivity Stratigraphic Transgressive F0 & Strat. Unit (API) OHM*M Shoreline Surface mFS 4 0 75 150 1 10 100 1000 2900 m

mFS 4

2901.30m 2910 m Falher L Falher

Spirit River Formation Spirit River 2920 m

Middle F4 Shoreface

2905.30m

Lower 2909.30m F3 Shoreface

2913.30m

Oﬀshore F2 Transition

2917.30m Depth (m) Interpreted F P VF M C Physical Biogenic VC Mud Gr & Strat. Silt Depositional Facies Sand Gravel Sedimentary Structures Surface Environment

106