Chapter 3 — Petroleum Assessment of the Chattanooga Shale/Floyd Shale-Paleozoic Total Petroleum System, Black Warrior

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Chapter 3 Petroleum Assessment of the Chattanooga Shale/Floyd Shale– Paleozoic Total Petroleum System, Black Warrior Basin, Alabama and

Mississippi Volume Title Page

By Mark J. Pawlewicz and Joseph R. Hatch

Chapter 3 of Geologic Assessment of Undiscovered Oil and Gas Resources of the Black Warrior Basin Province, Alabama and Mississippi

Compiled by Joseph R. Hatch and Mark J. Pawlewicz

U.S. Geological Survey Digital Data Series DDS–69–I

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

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Suggested citation: Pawlewicz, Mark, J., and Hatch, Joseph R., 2007, Petroleum assessment of the Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System, Black Warrior Basin, Alabama and Mississippi, in Hatch, Joseph R., and Pawlewicz, Mark J., compilers, Geologic assessment of undiscovered oil and gas resources of the Black Warrior Basin Province, Alabama and Mississippi: U.S. Geological Survey Digital Data Series DDS–69–I, chap. 3, 23 p.

ISBN 1-411-31775-0 iii

Contents

Overview ………………………………………………………………………………………… 1 Geologic Setting ………………………………………………………………………………… 1 Stratigraphic Framework………………………………………………………………… 1 Structural Framework …………………………………………………………………… 5 Hydrocarbon Source-Rock Characterization… ………………………………………………… 6 Organic Carbon … ……………………………………………………………………… 6 Hydogen Index–Organic Facies… ……………………………………………………… 7 Organic Matter Thermal Maturity… …………………………………………………… 7 Thermal Maturity Modeling……………………………………………………………… 8 Hydrocarbon Chemistry… ……………………………………………………………………… 9 Natural Gas Chemistry…………………………………………………………………… 9 Oil Chemistry… ………………………………………………………………………… 9 Carboniferous Sandstones Assessment Unit …………………………………………………… 9 Reservoir Rocks… ……………………………………………………………………… 9 Hydrocarbon Exploration and Production History… …………………………………… 9 Assessment Data………………………………………………………………………… 14 Assessment Results… ………………………………………………………………… 19 Pre-Mississippian Carbonates Assessment Unit … …………………………………………… 19 Reservoir Rocks… ……………………………………………………………………… 19 Assessment Unit Analog ………………………………………………………………… 19 Production History ……………………………………………………………………… 21 Assessment Data………………………………………………………………………… 21 Assessment Results … ………………………………………………………………… 22 References Cited………………………………………………………………………………… 22

Figures

1. Map showing areal distribution of the Chattanooga Shale/Floyd Shale– Paleozoic Total Petroleum System (TPS), Pre-Mississippian Carbonate Assessment Unit (AU), and Carboniferous Sandstones AU in the Black Warrior Basin Province……………………… 2 2. Generalized stratigraphic column for the Black Warrior Basin… ………………………… 3 iv

3. Floyd Shale depositional cycles… …………………………………………………… 4 4. Map showing tectonic setting of the Black Warrior Basin… ………………………… 5 5. Cross sections showing structural relations of Paleozoic rocks across the Black Warrior Basin………………………………………………………………………… 6 6. Stacked bar histogram of organic carbon contents for 19 Floyd Shale samples and 8 Chattanooga Shale samples from the Black Warrior Basin… ……………………… 7

7. Stacked bar histogram of hydrogen indices (mg S2/gTOC) for 19 Floyd Shale samples and 8 Chattanooga Shale samples from the Black Warrior Basin, Alabama and Mississippi… ………………………………………………………………………… 7 8. Plot showing relation between burial history and thermal conditions with respect to oil and gas generation in the Chattanooga Shale–Parkwood Formation stratigraphic interval in Pickens County, Alabama… ……………………………………………… 8 9. Map showing distribution of gas wetness for samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin… ………… 10 10. Plot of gas wetness relative to depth for samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin… ………………………… 10 11. Map showing distribution of carbon dioxide contents (mole percent) for gas samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin………………………………………………………………………… 11 12. Plot showing C10+ saturated hydrocarbon distribution for oil produced from the “Millerella” sandstone, Blowhorn Creek oil unit, Lamar County, Alabama…………… 12 13. Plot of gravity (ºAPI) relative to reservoir depth for 31 oil samples from the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin… ………… 12 14. Events chart for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin………………………………………………………………………… 13 15.–21. Graphs showing: 15. New-field wildcat oil and gas wells relative to well-completion year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin……… 15 16. Grown gas-accumulation size relative to accumulation-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin……… 16 17. Grown gas-accumulation size relative to accumulation rank by size for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin……… 16 18. Grown oil-accumulation size relative to accumulation-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin……… 17 19. Grown oil-field size relative to accumulation rank by size for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin…………………… 17 20. Gas reservoir depth relative to reservoir-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin…………………… 18 21. Oil reservoir depth relative to reservoir-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin…………………… 18 22. Total petroleum system events chart for the Pre-Mississippian Carbonates Assessment Unit in the Black Warrior Basin………………………………………… 19 23. Borehole profile showing Cambrian-Ordovician source rocks in fault contact with Carboniferous source rocks… ……………………………………………………… 20 24. Plot of new-field wildcat gas wells relative to well-completion year for the Pre-Mississippian Carbonates Assessment Unit in the Black Warrior Basin… …… 21

Tables

1. Ranges and median values of total organic carbon and hydrogen index for core samples from the Floyd Shale and Chattanooga Shale in the Black Warrior Basin… …… 6 13 2. Ranges and median values of gas wetness, N2 content, CO2 content and δ C, for produced gases from the Carboniferous Sandstone Assessment Unit in the Black Warrior Basin……………………………………………………………………………… 9 3. Ranges and median values of oil gravity (ºAPI), pristane/phytane ratios, and δ13C of saturated and aromatic hydrocarbon fractions of oils from the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin………………………………… 11 4. Ten most productive gas fields in the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin… …………………………………………………………………… 14 5. Five most productive oil fields in the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin… …………………………………………………………………… 15 Petroleum Assessment of the Chattanooga Shale/ Floyd Shale–Paleozoic Total Petroleum System, Black Warrior Basin, Alabama and Mississippi

By Mark J. Pawlewicz and Joseph R. Hatch

Overview

The total petroleum system approach was used to “Lewis,” “Evans,” “Sanders,” “Carter,” and “Millerella” estimate the undiscovered petroleum resources of the sandstones) and the Lower-Middle Pennsylvanian Pottsville Chattanooga Shale/ Floyd Shale–Paleozoic Total Petroleum Formation (including the informally named “Fayette” and System (TPS) in the Black Warrior Basin Province in Alabama “Nason” sandstones), with gas and oil trapped by a variety and Mississippi. The TPS was defined geologically, and two of basement-involved fault blocks, stratigraphic traps, and a conventional assessment units (AU), the Pre-Mississippian combination of structural and stratigraphic traps (fig. 2). Carbonate AU and Carboniferous Sandstones Assessment Unit, were evaluated formally. Based on the numerical code system established to identify individual provinces, petroleum Stratigraphic Framework systems, and assessment units (Klett and others, 1997), the Black Warrior Basin Province is numbered 5065, the As described by Thomas (1972), the Upper Mississippian Chattanooga Shale/Floyd Shale–Paleozoic TPS is numbered Floyd Shale is primarily dark gray shale that constitutes 506501, and the Pre-Mississippian Carbonates AU and the lower part of the clastic sequence overlying the Upper Carboniferous Sandstones AU are numbered 50650101 and Mississippian Tuscumbia Limestone and the Lower 50650102, respectively. Geologic data considered in defining Mississippian Fort Payne Chert in the Black Warrior Basin TPS and AU boundaries included source-rock distribution (fig. 2). The shale is believed to be primarily the prodelta and thickness, overburden thickness, faulting intensity, and facies of a major regressive wedge that grades upward into organic-matter thermal maturity. Historical production data the Upper Mississippian Bangor Limestone and Parkwood were used to estimate volumes of gas in undrilled areas. Formations and includes beds equivalent to the Hartselle Sandstone and “Evans” and “Lewis” sandstones and shales. The Floyd Shale includes back-barrier marine, lagoonal, and Geologic Setting marginal marine clays and is believed to have been derived from the southwest and transported toward the northeast. The The Chattanooga Shale/Floyd Shale–Paleozoic TPS unit thickens to the northeast, reaching a maximum of (fig. 1) extends approximately from the Appalachian fold and 600 ft in depocenters along the Appalachian downwarps thrust belt on the southeast side of the Black Warrior Basin to (fig. 3) (Thomas, 1972). Sandstone beds as much as 80 ft the Nashville dome on the north and to the buried Ouachita thick, siderite nodules, shaly argillaceous limestone, and structural front to the southwest in central Mississippi. calcareous shale and chert are included in the formation. Regarding the two conventional AUs defined within the In the eastern part of the Black Warrior Basin, in northern TPS: (1) the Pre-Mississippian Carbonates AU consists of Alabama, the Upper Devonian Chattanooga Shale and the platform carbonate reservoirs in the Cambrian and Lower Lower Mississippian Maury Shale have a combined thickness Ordovician Knox Group and the Middle Ordovician Stones of less than 50 ft. These two shales thin and pinch out to the River Group, with gas trapped by basement-controlled fault west and south, and in Mississippi they form discontinuous blocks and possible ramp anticlines associated with frontal black shale units. The Chattanooga Shale rests unconformably thrust faults and facies changes; and (2) the Carboniferous on Silurian and Ordovician strata in the eastern part of the Sandstones AU consists of fluvial, deltaic, and shallow-marine basin, whereas the shale oversteps the eastward-thinning sandstone reservoirs in the Upper Mississippian Floyd Shale Lower Mississippian Fort Payne Chert in the western part of and Parkwood Formation (including the informally named the basin (Thomas, 1988). Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

² ² ² ² ² ²

TENNESSEE ²

MISSISSIPPI ALABAMA

Prentiss Colbert Tishomingo Lawrence Union Lafayette Franklin Morgan Panola Lee Itawamba Quitman Pontotoc Marion Winston Cullman ² Yalobusha Tallahatchie Chickasaw Calhoun Monroe Grenada Lamar Walker Fayette Clay Montgomery Webster Jefferson Leflore Oktibbeha Lowndes Carroll Choctaw Pickens Tuscaloosa

² Attala Noxubee Winston 4%..%33%% Greene

",!#+ Kemper 7!22)/2 CHATTANOOGA SHALE/ Hale "!3). FLOYD SHALE–PALEOZOIC TPS AND Sumter -)33)33)00) !,!"!-! PRE-MISSISSIPPIAN CARBONATES AU

-),%3 CARBONIFEROUS SANDSTONES AU ² +),/-%4%23

Figure 1. Areal distribution of the Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System (TPS), Pre-Mississippian Carbonate Assessment Unit (AU), and Carboniferous Sandstones AU in the Black Warrior Basin Province, northwestern Ala- bama, and northeastern Mississippi. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System

(# ERA SYSTEM SERIES GEOLOGIC UNIT Explanation LITHOLOGY02/$5#%$ “Coal zones” Coal "Nason” sandstone Middle and "Fayette” sandstone Lower Shale or claystone "Benton” sandstone

Pennsylvanian "Robinson” sandstone Pottsville Formation "Chandler” sandstone ? ? ? Siltstone "Coats” sandstone

"Gilmer” sandstone “Cooper” sandstone Shaly sandstone

"Millerella” limestone "Millerella” sandstone #ARBONIFEROUS "Carter” sandstone Sandstone

Upper Parkwood Formation “Sanders” sandstone Bangor Limestone Conglomeratic sandstone Hartselle Sandstone Mississippian

"Evans” sandstone Limestone "Lewis” limestone

Floyd Shale "Lewis” sandstone Tuscumbia Limestone Oolitic limestone Lower Fort Payne Chert

Paleozoic Chattanooga Shale Cherty limestone unnamed cherty limestone Devonian Argillaceous limestone

undifferentiated rocks Dolomitic limestone Silurian

Upper & undifferentiated Middle rocks Dolomite ? ? ? Stones River Middle Group Undifferentiated

Ordovician Lower igneous rocks Knox Group Upper Ketona Dolomite Gas Middle Conasauga Formation Oil and gas

Cambrian Lower Rome Formation

Precambrian basement complex

Figure 2. Generalized stratigraphic column for the Black Warrior Basin, Alabama and Mississippi. Unit names in quotes. are informal names of local usage. After Montgomery 1986; also modified in part from Popov and others (2001, their fig. 13). Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province e l

l Pride Mtn. Fm s a e i e S e s l b e t m n l c r c y u o m d r a t t

y feet c e u o o s H a l c s c l e d o g e i e l s D s l e y n s a w s w u n 0 0 m d 0 0 0 o e L a t i h k l l T e a 0 d r 0 0 0 r B L c F S i L v m a a 1 3 2 4 y ' E F M P H c h A t 3 r 8 o 0 s N 3 e d r r a u 5 t 1 w 9 a 1 p d r 3 n u a 4 g g i w n 8 s i p 0 n u y 0 e t y 5 g i s k r n v c i i a o t 0 n o r l i s 1 e C B F i k s r e a 2 R 9 m 2 e 5 n o t s s e 6 l e e l 3 a i 5 2 m h i m 6 s s l , e k a N l e c l n n a i e l l O r o 1 I b t e l 9 n s T l e i 2 d o v A 5 i e i M n t t n f a N c a s o o l a 0 , t A s o e e p i l L r r e o a d r e P t a h m : b o i X S l R m C m E u u t a n 5 D t 3 i 6 5 4 m r ) ) s s e S L p ( ( ) 9 e e h 0 n n S 0 o o ( t t 3 s s s e e l d e a n p m h i a y S L S t 4 1 k 1 c 3 o R 8 9 2 3 n o 4 i 7 t 6 p a 5 a c o m L 2 2 2 4 m F d o o r w e k p r Floyd Shale depositional cycles. Modified from Pashin and Rindsberg (1993). County names for location map given in figure 1. ' p A a A L U P

. 0 A 3 h 7 t 5 S u a 4 i d A o d s h b o M S S o S o e o s m ) l i r l w d u Figure d w e a w k y c k d r e s e i w r o l a m L s u N a m o F ( M P F T L L P F Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System

Structural Framework faults, apparently of Early Pennsylvanian age, have placed As described by Thomas (1988), the structural framework Carboniferous rocks in fault contact with Lower Ordovician of the Black Warrior Basin can be broadly characterized as a and Cambrian strata (Thomas, 1988). Seismic data from the homocline that dips southwest toward the Ouachita orogenic southwestern part of the basin indicate as much as 9,800 ft of belt and contains numerous superimposed folds and faults displacement on down-to-the-southwest faults. (fig. 4). On the southeast margin of the basin, folds of the During the Mesozoic and Cenozoic, the Black Warrior Appalachian thrust belt are superimposed on the homocline. Basin began to tilt to the southwest toward the axis of the The Paleozoic strata are complexly faulted (fig. 5). Major Mississippi embayment. Fault systems originating during this faults trend northwest, and normal faults have dips of 60–70o time period, which were associated with the opening of the (Pike, 1968). In southeastern Mississippi, normal and thrust Gulf of Mexico, crosscut Paleozoic structures.

91° 90° 89° 88° 87° 86°

Nashville dome Tennessee 35° Mississippi Outcrop limit of Subcrop limit of Pennsylvanian strata Pennsylvanian Ouachita strata

34° orogenic belt

Black Warrior t el Alabama Basin Province b 33° orogenic ian Appalach Eastern limit of Tertiary and Cretaceous rocks Thrust fault, teeth in upper plate 4%..%33%%

32° ",!#+ 7!22)/2 -),%3 "!3).

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Figure 4. Tectonic setting of the Black Warrior Basin, Alabama and Mississippi. Modified from Thomas (1988), Ryder (1994), and Popov and others (2001, their fig. 11). Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

B B' Explanation 10 11121314 15 16 17 7 0 Cenozoic Sea level Mesozoic -1 Pennsylvanian t

Upper Mississippian e -2 b

c t i i

n Lower Mississippian h

c e Devonian -3 a g 7 B' u o r 17 Tennessee

O Silurian o Upper and Middle Ordovician -4 16 C' i

a p 29 i

15 s m

s a i

b 8 Lower Ordovician s s a -5 14 i l 28

A Cambrian 13 M 27 12 25 26 11 B 10 23 24 Precambrian Miles 20 22 C 18 19 21

C C' 18 19 20 21 22 23 24 25 26 27 28 8 29 0 Sea level -1

-2 e

c t i Horizontal scale i n h -3 c e a g

u o

O 0 60 MILES o -4

-5

Miles Figure 5. Cross sections showing structural relations of Paleozoic rocks across the Black Warrior Basin, Alabama and Mississippi. From Thomas (1988).

Hydrocarbon Source-Rock and 2.4 to 12.7 wt % (mean 4.6 wt %) for the Chattanooga Characterization Shale. Ronov (1958) estimated a critical minimum TOC of 0.5 wt % for shale to be an effective hydrocarbon source rock; so, Hydrocarbon source-rock potential is dependent on the on that basis, most intervals within the two formations qualify amount, composition, and thermal maturity of organic matter as potential hydrocarbon source rocks. Even though the Floyd in the rock. The amount of organic matter is measured by the total organic carbon (TOC) content, the relative hydrogen Table 1. Ranges and median values of total organic carbon and richness (hydrogen index, HI) of the organic matter, the hydrogen index for core samples from the Floyd Shale and Chat- ® Rock-Eval hydrogen index (S2/TOC, in milligrams per gram tanooga Shale in the Black Warrior Basin, Alabama, and Missis- [mg/g]), the Rock-Eval® Tmax (°C) thermal maturity, and the sippi. Data are for samples where Rock-Eval® Tmax ≤ 450º and vitrinite reflectance (% oR ) thermal maturity. Median values total organic carbon ≥ 0.5 percent. and ranges for TOC and HI for 19 Floyd Shale and eight [TOC, total organic carbon; wt %, weight percent; HI, hydrogen index; mg Chattanooga Shale core samples are summarized in table 1. HC/g TOC, milligrams of hydrocarbons per gram of TOC. Data listed in The distributions of TOC and HI for these samples are shown Carroll and others (1995, their table 8-3)]. in figures 6, and 7, respectively. Number of TOC HI Unit samples (wt %) (mg HC/gTOC) Range 0.5–10.2 Range 42–345 Floyd Shale 19 Organic Carbon Mean 1.8 Mean 145 Range 2.4–12.7 Range 140–350 As indicated in table 1, TOC ranges from 0.5 to 10.2 Chattanooga Shale 8 Mean 4.6 Mean 260 weight percent (wt %) (mean 1.8 wt %) for the Floyd Shale Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System

Floyd Shale Chattanooga Shale S N

O 9 I T A V R E

S Figure 6. Stacked bar histogram B 6 O

of organic carbon contents for 19 F O

Floyd Shale samples and 8 Chat- R

E tanooga Shale samples from the B

M Black Warrior Basin, Alabama and 3 U

N Mississippi. Samples are those where Rock-Eval® Tmax ≤ 450ºC and total organic carbon ≥ 0.5 0 percent. Wt %, weight percent. 0.5 to 1 1 to 2 2 to 4 4 to 8 8 to 12 >12 ORGANIC CARBON (wt %) 15

S Floyd Shale N Figure 7. Stacked bar histogram

O Chattanooga Shale I

T of hydrogen indices (mg S2/gTOC) A 10

V for 19 Floyd Shale samples and 8 R

E Chattanooga Shale samples from S

B the Black Warrior Basin, Alabama O

F and Mississippi. Samples are those O 5 where Rock- Eval® Tmax ≤ 450ºC R

E and total organic carbon content ≥ B

M 0.5 percent; boundaries for organic U

N facies D through A from Jones 0 (1987). <, less than; >, greater than. <50 50-125 125-250 250-400 400-650 650-850 >850 D CD C BC B AB A

HYDROGEN INDEX AND ORGANIC FACIES Shale has less organic matter, it probably is the primary gas, and hydrocarbons generated from organic facies C are contributor of hydrocarbons to the TPS because of its much nearly always condensate and gas. Organic facies CD has a greater thickness — as much as 200 ft locally — compared to moderate capacity for dry gas generation, whereas organic the average thickness of only 10 ft for the Chattanooga Shale. facies D is essentially nongenerative (Jones, 1987). As summarized in table 1 and shown in figure 7, organic matter in the Floyd Shale primarily represents organic facies Hydrogen Index – Organic Facies C (median HI = 150, with the range in compositions from organic facies BC to D). Organic matter in the Chattanooga Hydrogen indices for the Floyd Shale samples range Shale is primarily organic facies BC and C (median HI = 260). from 42 to 345 mg/g, whereas HI for the Chattanooga Shale Under thermally mature conditions, organic matter in the samples range from 135 to 350 mg/g. Nevertheless, the Floyd Shale should primarily generate gas and gas condensate median HI is lower for the Floyd Shale (150 mg/g) than for the with some oil, whereas organic matter in the Chattanooga Chattanooga Shale (260 mg/g). Shale should generate both oil and gas according to data on Jones (1987) defined a series of organic facies (labeled organic-facies types published by Tissot and Welte (1978). A–D) for rocks based on microscopic and chemical characteristics (HI, H/C ratios) of organic matter that is marginally mature with respect to petroleum generation (Ro Organic Matter Thermal Maturity about 0.50). Organic facies A has the highest potential for oil generation, and facies AB also has high potential for oil. Rock-Eval® Tmax measurements of organic matter in 29 Organic facies B, however, is the source of most of the world’s Floyd Shale samples and 9 Chattanooga Shale samples from oil. Organic facies BC has capacity to generate both oil and northwestern Alabama are listed in Carroll and others (1995, Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province their table 8–3). Tmax for the Floyd Shale samples ranges from Thermal Maturity Modeling 432º to 497ºC, and Tmax for the Chattanooga Shale samples ranges from 433º to 454ºC; these values indicate that the Lopatin modeling (fig. 8) of the stratigraphic interval organic matter is thermally mature with respect to hydrocarbon from the Devonian Chattanooga Shale through the Upper generation (Espitalié and others, 1977). Mississippian Parkwood Formation in Pickens County, west- Vitrinite reflectance measurements for seven Floyd Shale central Alabama, provides evidence for a complex burial samples and one Chattanooga Shale sample from northwestern and thermal history and enables some generalizations to Alabama, as listed in Carroll and others (1995, their table 8–1), be made about burial and hydrocarbon generation (Telle show Ro values that range from 0.92 percent to 1.6 percent, and others, 1987; Hines, 1988; Carroll and others, 1995). confirming that organic matter in the samples is thermally Major thermal maturation apparently took place during mature with respect to hydrocarbon generation. rapid burial of the foreland basin that was associated with In their study of the thermal maturity of Devonian through Appalachian-Ouachita orogenesis. For example, coal in Pennsylvanian strata in the Black Warrior Basin in northwestern the Lower Pennsylvanian Pottsville Formation, which Alabama, Carroll and others (1995) observed a general increase overlies the Parkwood Formation, attained a high-volatile-A of thermal maturity with depth based on Ro values derived from bituminous rank during maximum burial at the end of the whole-rock preparations of borehole cuttings. Additionally, Paleozoic (251 Ma). It is noteworthy that major thermogenic their results indicated a general increase of thermal maturity oil and gas generation is thought to have occurred at that from the northwestern part of the basin in Alabama toward the time. According to the Lopatin models, however, minor south, corresponding to the increased depth of burial shown on a thermogenic gas generation may have continued during post- regional cross section by Thomas (1988). orogenic unroofing, but generation was effectively completed

1 23 4 5 6 7 0 70 Onset of thermal 6 7 gas generation 2,000 90 4 5 110 4,000 Onset of oil 3 generation 130 6,000 2 End of oil generation 150 1 8,000 170 TEMPERATURE (ºF) TEMPERATURE 1- Base of Chattanooga Shale 10,000 2- Top of Parkwood Formation 3- Preserved Pottsville Formation 190 4- Eroded section (Pennsylvanian + Permian?) 5- Base of Cretaceous Tuscaloosa Group

DEPTH BELOW SURFACE, IN FEET DEPTH BELOW SURFACE, 6- Cretaceous - Holocene unconformity 210 12,000 7- Eroded section

–350 –300 –250 –200 –150 –100 –50 0 TIME (MYBP)

Figure 8. Relation between burial history and thermal conditions with respect to oil and gas generation in the Chattanooga Shale– Parkwood Formation stratigraphic interval in Pickens County, Alabama. Modified from Carroll and others (1995, their fig. 4), and Pashin and Hinkle (1997, their fig. 26). MYBP, million years before present. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System and unaffected by Late Cretaceous reburial by Gulf Coastal A representative saturated hydrocarbon distribution of an Plain and Mississippi Embayment strata. oil sample is shown in figure 12. This oil, from the Blowhorn Creek field in Lamar County, Alabama, is characterized by a gradual decrease in the amounts of n-alkanes between

C10 and C30, no significant odd-even numbered n-alkanes, Hydrocarbon Chemistry and relatively abundant pristane and phytane with a pristane/phytane ratio near 1.3. This saturated hydrocarbon distribution is similar to that of oils derived from Upper Natural Gas Chemistry Devonian–Mississippian shales in other eastern Paleozoic-age basins (for example, see saturated hydrocarbon distribution for oil from the Mississippian Aux Vases Sandstone in the Chemical analyses of produced gases from the Illinois Basin in Hatch and others, 1991, their fig. 24–8). Chattanooga Shale/Floyd Shale–Paleozoic TPS (mainly a dry A plot of oil gravity relative to reservoir depth for 31 oil gas system due to its composition of organic matter with low samples from the Mississippian and Pennsylvanian sandstone hydrogen content) are summarized in table 2. The analyses, reservoirs (fig. 13) shows an increase in ºAPI gravity with from Moore and Sigler (1987) and Hamak and Sigler (1991), depth of the reservoir, indicating an increase in thermal represent gas samples from Mississippian and Pennsylvanian maturity with increasing depth (Carroll and others, 1995). sandstone reservoirs of the Carboniferous Sandstones AU This increase in oil gravity with depth parallels the increase and demonstrate a wide range of compositions. Median gas in gas wetness with depth shown in figure 10. wetness is 3.7 percent (range 0.1 to 28.5 percent), with a general increase from north to the south (fig. 9). The increase in gas wetness from north to south is related to an increase in depth (fig. 10) that is likely caused by increased thermal maturity to the south (as shown by Carroll and others, 1995). Carboniferous Sandstones Assessment Median contents of CO (0.10 percent) and N (1.3 percent) 2 2 Unit are low, with neither showing any systematic changes within the basin (for example, the distribution of CO2 contents shown in fig. 11). These produced gases contain no measurable 2H S. The geologic model for the Carboniferous Sandstones No gas analyses are available from reservoirs of the Pre- AU is characterized by gas and oil being trapped in Upper Mississippian Carbonate AU. Mississippian and Lower Pennsylvanian fluvial, deltaic, and shallow-marine sandstone reservoirs by a variety of Table 2. Ranges and median values of gas wetness, N2 content, 13 basement-involved fault blocks as well as in stratigraphic CO2 content and δ C, for produced gases from the Carboniferous Sandstone Assessment Unit in the Black Warrior Basin, Alabama traps and combined structural-stratigraphic traps. Source rocks and Mississippi. are the Upper Devonian Chattanooga Shale and the Upper Mississippian Floyd Shale (figs. 2, 3, 14). [Gas wetness %, 100 times (1–[C1, mole %/ΣC1–C3 mole %]); PDB, Pee Dee belemnite standard. Anlayses from Moore and Sigler (1987) and Hamak and Sigler (1991). %, percent; ‰ parts per thousand] Reservoir Rocks Number Measured component of Range Median The reservoir rocks of the Carboniferous Sandstones samples AU include various sandstones in the Upper Mississippian Gas wetness 88 0.1 to 28.5 3.7 Parkwood Formation and the Lower-Middle Pennsylvanian

CO2 content (mole %) 88 <0.01 to 27.7 0.1 Pottsville Formation (figs. 2, 3). These sandstones are part of a clastic wedge that was deposited in a variety of terrestrial N2 content (mole %) 88 <0.01 to 9.8 1.3 δ13 C (‰ PDB) 6 –47.2 to –49.8 –49.2 to open-marine environments (Kugler and Pashin, 1994). 1 The “Carter” sandstone of the Parkwood Formation, the most prolific oil producer in the basin, for example, originated as Oil Chemistry deltaic, beach barrier, and shelf-bar deposits (Bearden and Mancini, 1985). Chemical analyses of oils produced from Mississippian and Pennsylvanian sandstone reservoirs of the Carboniferous Sandstones AU are summarized in table 3. The analyses, Hydrocarbon Exploration and Production History including oil gravity (ºAPI), pristane/phytane ratios, and δ13C for the saturated and aromatic hydrocarbon fractions, are Hydrocarbon exploration and production history of the compiled from Carroll and others (1995). Carboniferous Sandstones AU are summarized as follows: 10 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

Franklin Lee Pontotoc Itawamba Gas wetness Marion Winston percent 0.0 – 0.9 Lamar Chickasaw Monroe 0.9 – 2.6 2.6 – 5.2 Walker Clay 5.2 – 9.2 Fayette 9.2 – 14.5 Lowndes 14.5 – 28.5

Pickens Tuscaloosa

Greene 4%..%33%%

-)33)33)00) !,!"!-!

ALABAMA -),%3 MISSISSIPPI

+),/-%4%23 )NDEXMAP

Figure 9. Distribution of gas wetness for samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black War-

rior Basin, Alabama and Mississippi (gas wetness percent = 100 x (1–[C1mole percent/ΣC1–C5 mole percent]).

0 T E E

F 2,000

N I

, H T P

E 4,000 D

R I O V R

E 6,000 S E R

8,000 0 5 10 15 20 25 30 GAS WETNESS, IN PERCENT Figure 10. Gas wetness relative to depth for samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black

Warrior Basin, Alabama and Mississippi. Gas wetness percent = 100 x (1–[C1mole percent/ΣC1–C5 mole percent]). Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 11

Franklin Lee Pontotoc Itawamba Carbon dioxide Marion Winston percent

Lamar 0.00 – 0.07 Chickasaw Monroe 0.07 – 0.23 Walker 0.23 – 0.70 Clay Fayette 0.70 – 1.50 1.50 – 3.20 Lowndes

Pickens Tuscaloosa

Greene TENNESSEE

MISSISSIPPI ALABAMA

ALABAMA MILES MISSISSIPPI 0 50

0 50 100 KILOMETERS Index map

Figure 11. Distribution of carbon dioxide contents (mole percent) for gas samples from reservoirs of the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi.

Table 3. Ranges and median values of oil gravity (ºAPI), pristane/phytane ratios, and d13C of saturated and aromatic hydrocarbon fractions of oils from the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama, and Mississippi. [PDB, Pee Dee belemnite standard; ‰, parts per thousand; oil gravity measurements and d13C analyses of saturated (sat.) and aromatic (arom.) hydrocarbons fraction listed in Carroll and others (1995, their table 8–4); pristane/phytane ratios and isotope analyses available from http://energy.cr.usgs.gov/other/index.htm] Number of Measured component Range Median samples Gravity (ºAPI) 31 21 to 43 34 Pristane/Phytane 24 1.13 to 1.55 1.28 δ13C sat. (‰ PDB) 23 –31.3 to –30.1 –30.64 δ13C arom. (‰ PDB) 23 –30.6 to –29.3 –29.87 1 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province 10 n-C “Millerella” sandstone Blowhorn Creek Unit Lamar County, Alabama 15 n-C pristane

phytane 20 n-C 25 Relative response n-C 30 n-C

Retention time

Figure 12. Plot showing C10+ saturated hydrocarbon distribution for oil produced from the “Millerella” sandstone, Blowhorn Creek oil unit, Lamar County, Alabama. After Carroll and others (1995, their fig.10).

0 T E E F 2,000 N I

, H T P E D 4,000 R I O V R E S

E 6,000 R

8,000 0 10 20 30 40 50 GRAVITY (oAPI)

Figure 13. Plot of gravity (ºAPI) relative to reservoir depth for 31 oil samples from the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. Modified from Carroll and others (1995, their fig. 8). Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 13 600 550 500 450 400 350 300 250 200 150 100 50 0 Geologic Time Mississippian Pennsylvanian Ordovician Cretaceous Precambrian Cambrian Paleogene Permian Devonian Jurassic Silurian Triassic Neogene Scale (MYBP) Petroleum

Olig. Systems Plio. Eoc. Mio. Pal. L M M M M L L E E E E E E E E E M L L L L L L L M E Events PK FP PV FS C ROCK UNIT SOURCE ROCK RESERVOIR ROCK SEAL ROCK OVERBURDEN ROCK TRAP FORMATION

GENERATION-MIGRATION- ACCUMULATION PRESERVATION CRITICAL MOMENT

Figure 14. Events chart for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. All features in the events chart are required to have a viable total petroleum system. PV, Pottsville Formation; PK, Parkwood Formation; FS, Floyd Shale; FP, Fort Payne Chert; C, Chattanooga Shale.

1. Gas production in the Black Warrior Basin was first “Carter” sandstone. The three largest nonassociated established in 1909 from Pennsylvanian sandstone in gas fields are the (a) Blooming Grove field in Fayette Fayette County, Alabama, at a depth of 1,400 ft. In and Lamar Counties (cumulative production, 68.8 1926, gas was discovered in Monroe County, Mis- billion cubic feet of gas [BCFG]; discovered in 1975), sissippi, in Upper Mississippian sandstone at a depth (b) Musgrove Creek field in Fayette County (cumula- of 2,400 ft. Exploration in the 1950s and early 1960s tive production, 44.0 BCFG; discovered in 1974), and was concentrated in and around Monroe County and (c) McGee Lake field in Lamar County (cumulative resulted in the discovery of several small gas fields production, 39.1 BCFG; discovered in 1979). and two noncommercial oil accumulations in Upper Mississippian sandstone reservoirs. The largest field 4. Through December 2003, 84 conventional non discovered during this phase of exploration was the associated gas fields, oil-associated gas fields, and oil Muldon field (Monroe County, Mississippi), which fields were discovered in the Mississippi part of the produced gas from the Upper Mississippian “Sanders” basin, predominantly in Upper Mississippian “Carter” sandstone at about 5,500 ft. and “Sanders” sandstone reservoirs. The three largest nonassociated gas fields are the (a) Corinne field 2. Renewed exploration activity in the 1970s and 1980s in Monroe, Lowndes, and Clay Counties (cumulative was initiated by the discovery of the East Detroit production, 152 BCFG; discovered in 1972), (b) the field (Lamar County, Alabama) in 1971. Ninety-five Muldon field in Monroe County (cumulative produc- gas, gas-associated oil, and oil fields were discovered during these two decades, including the two largest tion, 64.9 BCFG; discovered in 1952), and (c) Splunge gas fields — Corinne field in Monroe, Lowndes, and field in Monroe County (cumulative production 35.8 Clay Counties, Mississippi (discovered in 1972), and BCFG; discovered in 1973). Blooming Grove field in Fayette and Lamar Counties, 5. Most oil fields have cumulative production less than Alabama (discovered in 1975), and the two largest oil 0.5 million barrels of oil (MMBO). Exceptions are the fields — North Blowhorn Creek field in Lamar County, (a) North Blowhorn Creek field in Lamar County, Ala- Alabama (discovered in 1979), and South Brush Creek bama (cumulative production, 6.2 MMBO), (b) South field in Lamar County, Alabama (discovered in 1985). Brush Creek field in Lamar County, Alabama (cumu- The 10 most productive gas fields are listed in table 4, lative production, 1.7 MMBO), (c) Blowhorn Creek and the 5 most productive oil fields are listed in table 5. field in Lamar County, Alabama (cumulative produc- 3. Through May 2002, 137 conventional nonassociated tion, 0.67 MMBO), (d) Bluff field in Lamar County, gas fields and oil-associated gas fields were discov- Alabama, (cumulative production 0.57 MMBO), and ered in the Alabama part of the Black Warrior Basin, (e) Maple Branch field in Monroe County, Mississippi the dominant reservoir being the Upper Mississippian (cumulative production, 0.94 MMBO). 1 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

6. A substantial deposit of asphalt, estimated to contain Drilling data in the Carboniferous Sandstones AU show 7.5 billion barrels of oil (BBO) (Wilson, 1987), exists an appreciable decline (more than half) in the number of new- within the Upper Mississippian Hartselle Sandstone field wildcat wells during the 15-year period between 1985 and the Pride Mountain Formation in north-central and and 2000 (fig. 15). Field size, in terms of gas accumulations, northwest Alabama. This deposit, the result of bio- also decreased during this period, as shown in figure 16, and degradation or oxidation due to subsequent subaerial this trend is further evidenced by a plot showing grown gas- exposure, was not evaluated in this assessment primar- field size compared to accumulation-rank size during the first-, ily because of its physical nature. The solid nature of second-, and third-thirds segments of the exploratory history the asphalt lends itself to surface mining, and use of of the AU (fig. 17). Similar plots for oil-field discoveries are the material has been mostly for roadbuilding, though shown in figures 18 and 19; although the plot of oil-field size the deposit has the potential to be refined into liquid relative to accumulation-size rank for the first and second hydrocarbon. halves of the exploratory history shows a decrease in field size, not enough information is available to indicate a specific trend. It should be noted, however, that the sizes of oil and gas fields Assessment Data are expected to decrease with time in any given AU, as larger fields generally are found early in the exploration history of a Details on assessment-data sheets and the assessment petroleum province. model are described in Schmoker and Klett (2000). For the Reservoir depths for most gas and oil fields discovered in Black Warrior Basin assessment, the minimum undiscovered the Carboniferous Sandstones AU during the 1970s and 1980s field sizes were set at 0.5 MMBO and 3.0 BCFG. remained between 1,500 and 5,000 ft (figs. 20, 21).

Table 4. Ten most productive gas fields in the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. [BCFG, billion cubic feet of gas; ss., sandstone; Fm., formation; MS, Mississippi; AL, Alabama. Mississippi data at http://www.ogb.state.ms.us/whatsnew.htm, accessed May 2004]

Discovery Cumulative produc- Field (State) County Productive units (s) year tion (BCFG) Corrine Clay, 1972 Nason ss.,1 Park- 152.0 (MS) Lowndes, Monroe wood Fm. Lewis ss.1 Blooming Grove Fayette, 1977 Parkwood Fm. 68.8 (AL) Lamar Muldon Monroe 1952 Sanders ss.1 264.9 (MS) Beaverton Lamar 1973 Parkwood ss.,1 45.4 (AL) Lewis ss.1 Musgrove Creek Fayette 1974 Carter ss.1 44.0 (AL) Buttahatchie River Monroe 1977 Carter ss.,1 28.7 (MS) Lewis ss.1 McGee Lake Lamar 1979 Carter ss.,1 39.1 (AL) Lewis ss.1 Splunge Monroe 1973 Carter ss.1 35.8 (MS) Star Lamar 1974 Parkwood Fm. 38.8 (AL) Lewis ss.1 McCracken Mountain Fayette 1974 Lewis ss.,1 36.2 (AL) Parkwood Fm., Pottsville Fm. 1 Informal name or local usage. 2 Gas storage. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 15

Table 5. Five most productive oil fields in the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. [MMBO, million barrels of oil; AL, Alabama; MS, Mississippi; ss., sandstone; Fm., formation. Mississippi data at http://www.ogb.state.ms.us./whatsnew.htm accessed May 2004] Field Cumulative produc- County Discovery year Productive unit(s) (State) tion (MMBO) North Blowhorn Creek Lamar 1979 Carter ss.1 6.21 (AL) South Brush Creek Lamar 1985 Carter ss.1 1.73 (AL) Maple Branch (MS) Monroe 1976 Lewis ss.1 0.94 Blowhorn Creek Lamar 1978 Parkwood Fm. 0.67 (AL) Bluff Fayette 1977 Parkwood Fm. 0.57 (AL)

1 Informal name of local usage.

120 S L

L 90 E W

T A C D L I 60 W

D L E I F -

W 30 E N

0 1910 1925 1940 1955 1970 1985 2000 WELL-COMPLETION YEAR

Figure 15. New-field wildcat oil and gas wells relative to well-completion year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. 1 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

1,000 E Z I S

N O I

T 100 A L U

) M G U F C C C B ( A - S

A 10 G

N W O R G

1 1910 1925 1940 1955 1970 1985 2000 ACCUMULATION DISCOVERY YEAR Figure 16. Grown gas-accumulation size relative to accumulation-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. BCFG, billion cubic feet of gas.

1,000

First third of accumulations

E discovered Z I Second third of S accumulations discovered N Third third of accumulations O I discovered T 100 A L U ) M G U F C C B C (

A - S

A 10 G

N W O R G

1 0 5 10 15 20 GAS-ACCUMULATION RANK BY SIZE Figure 17. Grown gas-accumulation size relative to accumulation rank by size for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. BCFG, billion cubic feet of gas. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 17

10 E Z I S

N O I T A L ) U O M B U M

C 1 M C (

A - L I O

N W O R G

0 1910 1930 1950 1970 1990 ACCUMULATION-DISCOVERY YEAR

Figure 18. Grown oil-accumulation size relative to accumulation-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. MMBO, million barrels of oil.

10 E Z I First half of accumulations S discovered N Second half of accumulations O I discovered T A L ) U O M B U M

C 1 M C (

A - L I O

N W O R G

0 0 1 2 3 4 OIL-ACCUMULATION RANK BY SIZE Figure 19. Grown oil-field size relative to accumulation rank by size for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. MMBO, million barrels of oil. 1 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

T E

E 2,500 F

N I

, H T

P 5,000 E D

R I O

V 7,500 R E S E R

S 10,000 A G

12,500 1910 1930 1950 1970 1990 RESERVOIR-DISCOVERY YEAR

Figure 20. Gas reservoir depth relative to reservoir-discovery year for the Carboniferous Sandstones Assessment Unit in the Black Warrior Basin, Alabama and Mississippi.

T E E

F 2,500

N I

, H T P

E 5,000 D

R I O V

R 7,500 E S E R

L I O

10,000

1910 1930 1950 1970 1990 RESERVOIR-DISCOVERY YEAR

Figure 21. Oil reservoir depth relative to reservoir-discovery year for the Carboniferous Sandstones Assessment Unit in the Black War- rior Basin, Alabama and Mississippi. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 19

Assessment Results River Group (fig. 2). This carbonate sequence represents the maximum transgression of a persistent shallow marine shelf Estimated undiscovered resources in the Carboniferous (Thomas, 1988). In Alabama, the sequence is as much as Sandstones AU include means of (1) 359.55 BCFG and 4,200 ft thick in the Appalachian fold belt, and 5,700 ft were 1.89 million barrels of natural gas liquids (MMBNGL) for penetrated in a well on the south flank of the Nashville dome, gas reserves, and (2) 5.91 MMBO, 8.26 BCFG, and 0.05 where the strata overlie Precambrian granite (Pike, 1968). MMBNGL for oil reservoirs (U.S. Geological Survey, 2003, The lower Knox Group consists primarily of cherty dolomite, their table 1). whereas the upper several hundred feet is interbedded limestone and dolomite, with the limestone content increasing to the southwest and the dolomite content increasing to the north (Kidd, 1975). The top of the Knox Group is at the top Pre-Mississippian Carbonates of the upper dolomite, generally referred to as the “Snow Assessment Unit zone,” which has vuggy porosity that is probably the result of subaerial exposure and karst development. The Middle Ordovician Stones River Group The Pre-Mississippian Carbonates AU consists of unconformably overlies the Knox Group. This carbonate Cambrian and Ordovician platform-carbonate reservoirs (fig. sequence (fig. 2) is 800 ft thick in the southern part of the 22), with gas having accumulated primarily in basement- Black Warrior Basin in Alabama and as much as 1,150 ft thick controlled fault block traps and possibly in traps formed in northern Alabama (Kidd, 1975). by frontal thrust faults and facies changes. Encompassing Extensional and possibly thrust faulting during the late a substantial portion of the Black Warrior Basin, this AU Paleozoic placed Mississippian source rocks in contact with the extends from the Appalachian fold-thrust front in Alabama Cambrian-Ordovician carbonate strata (fig. 23). Gas generated west to the edge of the Ouachita orogenic belt in Mississippi from the organic-rich Floyd Shale migrated along faults into the (fig. 4). The Upper Mississippian Floyd Shale is the likely karstic reservoirs. Geologic mapping indicates that extensional source rock; commonly, this shale sequence is in fault contact faults are widespread in the Black Warrior Basin. with the carbonate reservoirs. Assessment Unit Analog Reservoir Rocks Hydrocarbon exploration and production in the Black The Pre-Mississippian Carbonates AU is largely Warrior Basin has primarily involved Mississippian and composed of carbonate rocks of the Upper Cambrian-Lower younger strata. As a result, there is a general lack of basin- Ordovician Knox Group and the Middle Ordovician Stones wide information pertaining to the older rocks, as well 600 550 500 450 400 350 300 250 200 150 100 50 0 Geologic Time Neogene Pennsylvanian Mississippian Ordovician Paleogene Precambrian Cambrian Cretaceous Scale Devonian Permian Jurassic Triassic Silurian (MYBP) Petroleum Systems Plio. Olig. Eoc. Mio. Pal. M M M M M E E E E E E E E L E M L L L L L L L L L E Events Und KG SR ROCK UNIT SOURCE ROCK RESERVOIR ROCK SEAL ROCK OVERBURDEN ROCK TRAP FORMATION

GENERATION-MIGRATION- ACCUMULATION PRESERVATION CRITICAL MOMENT

Figure 22. Total petroleum system events chart for the Pre-Mississippian Carbonates Assessment Unit in the Black Warrior Basin, Alabama and Mississippi, showing relative timing of geologic features. All features in the events chart are required to have a viable total petroleum system. Und, undifferentiated Upper and Middle Ordovician rocks; SR, Stones River Group; KG, Knox Group. 20 Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

28-5 Amoco-Stack #1 Lucky 6-8N-16E Lauderdale Co., MS Mississippian 6,000'

Devonian Datum Silurian 7,000' Ordovician Stones River Limestone Stones River Dolostone 8,000'

Knox Limestone

Thrust Fault 9,000'

rend

10,000'

Appalachian Knox Dolostone 11,000' Cambrian Copper Ridge Dolostone 12,000'

Thrust fault Carboniferous 13,000' Explanation: , fault

14,000' Total Depth 14,110'

Figure 23. Borehole profile showing Cambrian-Ordovician source rocks in fault contact with Carboniferous source rocks. Borehole is located in Lauderdale County, Mississippi. From Henderson (1991). Depth below land surface, in feet. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System 1 as uncertainty regarding detailed fault relations between Production History the Cambrian/Ordovician reservoir rocks and the upper Paleozoic source rocks. For these reasons, an analog of Through December 2003, cumulative gas production the Arkoma Basin in Arkansas and Oklahoma was used to from the Cambrian and Lower Ordovician Knox Group in the provide a better understanding of the geologic setting and the Maben field in Oktibbeha County, Mississippi (discovery date, conditions leading to hydrocarbon generation, migration, and 1970), was 31.2 BCFG, of which 95 percent (29.5 BCFG) accumulation with respect to the Pre-Mississippian Carbonates was produced after 1998. The production numbers show AU in the Black Warrior Basin. Both basins are foreland considerable variability within the last 3 years — 5.9 BCFG in basins created during Ouachita/Appalachian orogenesis, when 2001, 9.14 BCFG in 2002, and 7.71 BCFG in 2003. Paleozoic rocks were thrust over the south and east margins of Well data for the Pre-Mississippian Carbonates AU the North American craton. show a substantial decline in the number of new-field wildcat The Cambrian-Ordovician Knox Group of the Black completions in the 10-year period between 1955 and 1965, Warrior Basin is equivalent in age to the Arbuckle Group of and that completions were intermittent from 1965 to the Oklahoma and Arkansas. Perry (1995) described the Arbuckle late1990s (fig. 24). These data, as well as data for discovered Group through the Devonian “Misener Sandstone” basement- field sizes and new-field wildcats, also demonstrate that the fault and shelf-gas play in the Arkoma Basin, which closely sizes of oil and gas fields decrease with time, following the resembles the Pre-Mississippian Carbonates AU in the Black trend discussed previously with respect to the Carboniferous Warrior Basin. Each of these (play or AU) share features Sandstones AU. A small upswing in the drilling of new-field such as deeply buried carbonate rocks capped by an erosional wildcat wells in the mid-to-late 1990s may be a reflection of unconformity and an associated thick zone of karstic porosity. economic conditions, such as the price of natural gas. Also, extensional basement faulting brought younger source rocks into contact with the carbonate rocks, providing fault- block structural traps. Assessment Data Each basin has had a single deep gas discovery, with limited if any additional discoveries. In the Arkoma Basin, Because the Pre-Mississippian Carbonates AU has the deep discovery well was in the Wilburton field, and the only one producing field (Maben), comparisons of field-size corresponding deep discovery well in the Black Warrior Basin distributions through time and determining changes in depths was in the Maben field. to newly discovered reservoirs through time were not possible.

8 S L

L 6 E W

T A C D L I 4 W

D L E I F -

W 2 E N

0 1910 1925 1940 1955 1970 1985 2000 WELL-COMPLETION YEAR

Figure 24. New-field wildcat gas wells relative to well-completion year for the Pre-Mississippian Carbonates Assessment Unit in the Black Warrior Basin, Alabama and Mississippi. Assessment of Undiscovered Oil and Gas, Black Warrior Basin Province

Assessment Results Klett, T.R., Ahlbrandt, T.S., Schmoker, J.W., and Dolton, G.L., 1997, Ranking of the world’s oil and gas provinces by Based on the analogy with the Wilburton field in the known petroleum volumes: U.S. Geological Survey Open- Arkoma Basin, estimated means of undiscovered resources File Report 97–463. in Pre-Mississippian Carbonates AU are 1,087 BCFG and 5.7 Kugler, R.L., and Pashin, J.C., 1994, Reservoir heterogeneity MMBNGL (U.S. Geological Survey, 2003, their table 1). The in Carter Sandstone, North Blowhorn Creek oil unit and largest expected gas field is estimated to be 218 BCFG. vicinity, Black Warrior basin, Alabama: Geological Survey of Alabama Bulletin 159, 91 p. Montgomery, S.L., 1986, The Black Warrior Basin—Proving References Cited the potential of the southeast, in Petroleum frontiers: Petro- leum Information Corporation Quarterly, v. 3, no. 3, 62 p. Bearden, B.L., and Mancini, E.A., 1985, Petroleum geology of Carter sandstone (Upper Mississippian), Black War- Moore, B.J., and Sigler, Stella, 1987, Analyses of natural rior Basin, Alabama: American Association of Petroleum gases, 1917- 85: Bureau of Mines Information Circular Geologists Bulletin, v. 69, no. 3, p. 361–377. 9129, 1197 p.

Carroll, R. E., Pashin, J. C., and Kugler, R. L., 1995, Burial Pashin, J.C., and Hinkle, Frank, 1997, Coal-bed methane in history and source-rock characteristics of Upper Devonian Alabama: Alabama Geological Survey Circular 192, 71 p. through Pennsylvanian strata, Black Warrior basin, Ala- Pashin, J.C., and Rindsberg, A.K., 1993, Origin of the carbon- bama: Alabama Geological Survey Circular 187, 29 p. ate-siliciclastic Lewis cycle (Upper Mississippian) in the Espitalié, J., Laporte, J.L., Madec, M., Marquis, F., Leplat, P., Black Warrior Basin: Geological Survey of Alabama Bul- Paulet, J., and Boutefeu, A., 1977, Methode rapide de car- letin 157, 54 p. acterisation des roches mares, et de leur potentiel petrolier Perry, W.J., 1995, National assessment of United States oil and et de leur degre d’evolution: Revue de l’Institut Francais du gas resources—Results, methodology, and supporting data: Petrole, v. 32, p. 23–42. U.S. Geological Survey Digital Data Series DDS–30. Hamak, J.E., and Sigler, Stella, 1991, Analyses of natural Pike, S.J., 1968, Black Warrior Basin, northeast Mississippi gases, 1986–90: Bureau of Mines Information Circular and northwest Alabama, in Beebe, B.W., ed., Natural gases 9301, 315 p. of North America: American Association of Petroleum Hatch, J.R., Risatti, J.B., and King, J.D., 1991, Geochemis- Geologists, Memoir 9, v. 2, p. 1693–1701. try of Illinois basin oils and hydrocarbon source rocks, in Popov, M.A., Nuccio, V.F., Dyman, T.S., Gognat, T.A., Leighton, M.W., Kolata, D.R., Oltz, D.F., and Eidel, J.J., Johnson, R.C., Schmoker, J.W., Wilson, M.S., Bartberger, eds., Interior cratonic basins: American Association of Charles, 2001, Basin-centered gas systems of the U.S.: Petroleum Geologists Memoir 51, p. 403–423. U.S. Geological Survey Open-File Report 2001–135, 1 CD Henderson, K.S., 1991, Cambro-Ordovician subsurface ROM. stratigraphy of the Black Warrior Basin in Mississippi: Ronov, A.B., 1958, Organic carbon in sedimentary rocks (in Mississippi Department of Environmental Quality, Office of relation to presence of petroleum): Translation in Geochem- Geology Report of Investigations 2, 51 p. istry, v. 5, p. 510–536. Hines, R.A., Jr., 1988, Carboniferous evolution of the Black Ryder, R.T., 1994, Black Warrior Basin, in Powers, R.B., ed., Warrior foreland basin, Alabama and Mississippi: Tusca- Petroleum exploration plays and resource estimates, 1989, loosa, University of Alabama, unpublished Ph.D. disserta- onshore United States—Region 8, Eastern Interior; Region tion, 231 p. 9, Atlantic Coast: U.S. Geological Survey Open-File Report Jones, R.W., 1987, Organic facies, in Brooks, J., and Welte, 94–211, p. 62–66. D., eds., Advances in petroleum geochemistry, volume 2: Schmoker, J.W., and Klett, T.R., 2000, U.S. Geological Survey London, Academic Press, p. 1–90. assessment model for undiscovered conventional oil, gas, Kidd, J.T., 1975, Pre-Mississippian subsurface stratigraphy of and ngl resources—The seventh approximation: U.S. Geo- the Warrior basin in Alabama: Gulf Coast Association of logical Survey Bulletin 2165. Geological Societies, Transactions, v. 25, p. 20–39. Petroleum Assessment—Chattanooga Shale/Floyd Shale–Paleozoic Total Petroleum System

Telle, W.R., Thompson, D.A., Lottman, L.K., and Malone, Tissot, B.P., and Welte, D.H., 1984, Petroleum formation and P.G., 1987, Preliminary burial-thermal history investiga- occurrence, second revised and enlarged edition: New York, tions of the Black Warrior basin: Implications for coal-bed Springer-Verlag, 699 p. methane and conventional hydrocarbon development: Tus- caloosa, University of Alabama, 1987 Coal-Bed Methane U.S. Geological Survey, 2003, Assessment of undiscovered Symposium Proceedings, p. 37–50. oil and gas resources of the Black Warrior Basin Province, 2002: U.S. Geological Survey Fact Sheet FS–038–03, 2 p. Thomas, W.A., 1972, Mississippian stratigraphy of Alabama: Geological Survey of Alabama Monograph 12, 121 p. Wilson, G.V, 1987, Characteristics and resource evaluation of the asphalt and bitumen deposits of northern Alabama: Thomas, W.A., 1988, The Black Warrior basin, in Sloss, L.L., Geological Survey of Alabama Bulletin 111, 11–0 p. ed., Sedimentary cover—North American craton: Geologi- cal Society of America, The geology of North America, v. D–2, p. 471–492.

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