the barnett shale (mississippian) in the central …

THE BARNETT SHALE (MISSISSIPPIAN) IN THE CENTRAL MIDLAND

BASIN (ANDREWS, ECTOR, MARTIN, AND MIDLAND COUNTIES)

By

CLARK H. OSTERLUND

Bachelor of Science, 2010 Baylor University

Waco, Texas

Submitted to the Graduate Faculty of The College of Science and Engineering

Texas Christian University In partial fulfillment of the requirements for the degree of

MASTER OF SCIENCE

August, 2012

Copyright By Clark Harrison Osterlund

2012

ii

ACKNOWLEDGEMENTS

First, I would like to thank Stonnie Pollock, Dexter Harmon, and the entire

exploration and IT department of Fasken Oil and Ranch Ltd., whose financial backing

made this project possible. I truly appreciate your interest in fostering my development

as a petroleum geologist and your generous help throughout the last couple of years.

I would also like to thank my parents for motivating me throughout this process

and for instilling in me the will to pursue my educational goals. In addition, I would like

to thank all of my friends that I have made at TCU these past two years for putting up

with me and for all the fun shenanigans we enjoyed. I have really had a blast here at

TCU.

Also, I would like to thank Dr. Donovan, whose teaching style stimulated my

desire to learn. I would like to thank Dr. Breyer for his initial help in getting this project

off the ground. Finally, a tremendous thanks to Dr. Helge Alsleben of TCU. Your

guidance and supreme editing skills has been a tremendous asset throughout this process.

Your willingness to make yourself accessible to students and unwavering motivational

support has made you an invaluable resource in the department.

iii

TABLE OF CONTENTS

Acknowledgements……………………………………………….….……………………ii

List of Figures…………………………………………………….………………………iv

List of Tables………………………………………………………………………...…...vi

Introduction…………………………………………………..……………………………1

Previous Work…………………………………………………………….………………3

Geographic and Geologic Setting…………………………………………………………4

Study Area and Methods………………………………………………………………….9

Division of Mississippian Strata…………………………………………………………12

Lithology…………………………………………………………………………………16

Geochemistry………………………………………………………………….…………22

TOC Estimation………………………………………………………………………….27

Age of Strata…………………………………………………………………….……….29

Sediment Accumulation…………………………………………………………….……33

Regional Context…………………………………………………………….…………..46

Structure of Study Area………………………………………………………………….48

Discussion………………………………………………………………..………………53

Production History……………………………………….………………………..……..54

Conclusions and Recommendations…………………………………..…………………57

References……………………………………………………………..…………………59

Appendix I. Geochemical Report……………………………………....……………….61

Appendix II. Paleontological Reports…………………………………………………..64

Vita

Abstract

iv

LIST OF FIGURES

1. Major geologic features of the Permian Basin region 2

2. Late Mississippian paleogeographic map 7

3. Location of Study area within the Midland Basin 10

4. Type log showing stratigraphic subdivisions 13

5. Synthetic seismogram for Mississippian section 14

6. Photomicrograph of the U.B.5 18




10. Photomicrograph of the basal U.B.2 21

11. Photomicrograph of the L.B.3 23

12. TOC wt. % vs. Depth 24

13. Oil potential (S2) 26

14. TOC estimation 28

15. Palynological results for the Fasken Fee BM #1 SWD 30

16. Palynological results for the Fasken Fee BL #1 SWD 31

17. Palynological results for the Amoco David Fasken BS #1 32

18. Gross isopach map of the Mississippian section 34

19. Gross isopach map of Mississippian Lime 35

20. Cross section A-A’ 36

21. Gross isopach map of lower Barnett 37

22. Type log showing >14 Ωm cutoff 39

v

23. Gross isopach map for the upper Barnett 40

24. Net isopach map for the upper Barnett 41

25. Cross section B-B’ 42

26. Cross section C-C’ 43

27. Gross isopach map of the U.B.2 44

28. Net isopach map of the U.B.2 45

29. Late Mississippian paleogeographic map of the Permian Basin region 47

30. Structure contour map on top of the Woodford Shale 49

31. Structure contour map on top of the L.B.3 50

32. Structure contour map on top of the U.B.2 51

33. Structure contour map on top of the U.B.6 52

34. Idealized deposition of bioclastic debris 55

35. Regional map of oil fields producing out of the upper Barnett 56

vi

LIST OF TABLES

1. Wells used in the construction of cross section and for palynological analysis 11

2. X-ray diffraction data from the Fasken Fee BM #1 SWD well 17

3. Rock-Eval pyrolysis and TOC data 23

1

Introduction

The Permian Basin of west Texas and southeastern New Mexico covers more than

86,000 mi2 (225,000 km2), and has produced in excess of 38 billion barrels of oil from

over 3,000 fields making it the largest onshore petroleum province in the United States

(Ball, 1995; IHS, 2011). The greater Permian Basin can be divided into various distinct

entities. The Central Basin Platform divides the basin into two separate sub-basins with

the Delaware Basin to the west and the Midland Basin to the east (Fig. 1). Stratigraphic

sections from all systems of the Paleozoic are present within the basin with established

production predominantly found in Pennsylvanian-Permian sections (Ball, 1995).

Mississippian strata constitute one of the least understood successions in the

Midland Basin in West Texas, despite being located in a mature petroleum province.

Increased activity in the “Wolfberry” (Permian) has led to a resurgence of interest in

previously under-evaluated sections including Mississippian units, which have been

successfully exploited for hydrocarbons in the Barnett Shale (Mississippian) in the Fort

Worth Basin. Part of the ambiguity surrounding the Mississippian strata stems from lack

of a general consensus on what constitutes Mississippian aged rocks. The present study

examines the depositional succession and evaluates the hydrocarbon potential of

Mississippian strata, which are constrained by palynology data, in the central portion of

the Midland Basin (Andrews, Ector, Martin, and Midland Counties).

The Woodford, Mississippian Lime, lower Barnett, and upper Barnett formations

were picked on well logs and seismic sections. These picks were incorporated in the

2

Figure 1. Regional map of the Permian Basin showing major geologic features. Yellow star shows approximate location of the study area and former maximum extent of the ancestral Tobosa Basin is shown in red (modified from Frenzel et al., 1988)

3

construction of cross-sections, structure maps and isopach maps, to establish the basic

depositional framework of the section. The upper Barnett was studied in more detail and

was further subdivided into sub-units that were also mapped. Sub-units consist of gravity

flows containing more desirable reservoir properties. The results offer insight into the

late stages of the evolution of the Tobosa Basin as well as late Mississippian

paleogeography.

In addition to palynology data, X-ray diffraction analysis, thin sections,

geochemical data, and well log analysis are used in this study. These data are used to

determine the overall lithology, clay content, and organic matter in the strata. The results

are related to the overall environment of deposition and are used to identify areas that

warrant focus for future exploration.

Previous Work

As a reflection on the historic dearth of production out of Mississippian strata in

the Midland Basin, there is scant literature concerning the overall Mississippian, let alone

Barnett Shale in the subsurface. A USGS study on Mississippian Systems of the United

States presents overviews on formations as well as depositional environments (Craig and

Connor, 1979). A more local study provided a detailed stratigraphic description of the

Mississippian strata in Gaines and Andrews Counties, Texas based on wireline logs and

well cuttings (Bay, 1954). In the Delaware Basin, deposition and subsequent diagenesis

of an upper Mississippian (Chesterian) oolitic shoal in Lea County New Mexico has been

characterized (Hamilton and Asquith, 2000). Driven by the success of the Barnett Shale

in the Fort Worth Basin, Ruppel and Kane (2006) compiled an updated overview for the

4

Barnett succession in the Permian Basin. Their report highlights some of the difficulties

in the interpretation of Mississippian carbonates solely off of wireline logs, specifically

differentiating between shallow- and deep-water facies.

While specific reports of reservoir properties are primarily found in unpublished

field reports, a concise overview on late Mississippian traps in the Midland Basin is

available (Candelaria, 1990). Though the succession was called “Atoka”, its use is

equivocal in the report. Subsequent workers adopted the age constraints as definite

(Wright, 2006), which added to the confusion about the age of the strata. The reservoir

units are described as an abnormally overpressured (7,500-10,000 psi or 50-70 MPa)

succession of units comprised of silty bioclastic constituents within an overall shale

sequence. Faunal components within the bioclastic debris, includes fenestrate bryozoans,

crinoids, ostracods brachiopods, oolites, and sponge spicules. The only published TOC

values range from 1.1-4.7% TOC (Candelaria, 1990).

Geographic and Geologic Setting

The Permian Basin encompasses regions of West Texas and southern New

Mexico, covering a portion of the North American craton. The Permian Basin is bounded

on the north by the Matador Arch, on the east by the eastern shelf and western flank of

the Bend Arch, on the south by the Marathon-Ouachita fold belt, and on the west by the

Salt-Flat graben (Fig. 1) (Frenzel et al., 1988). The basin is divided into the deep

Delaware Basin to the west, and the shallower Midland Basin to the east. Separating the

Delaware and Midland Basins is the Central Basin Platform, which was a platform

capped by carbonate reefs in the Permian (Frenzel et al., 1988). Prior to the formation of

5

the Permian Basin, its predecessor, the Tobosa Basin occupied a larger area. The Tobosa

Basin existed from the Cambrian to the Early Pennsylvanian as a structural depression

(Adams, 1965; Miall, 2008). Over that time span, the Tobosa Basin subsided and

received around 7,000 feet (2,330 meters) of Paleozoic sediment (Adams, 1965).

Scant information is available on Precambrian strata as few wells penetrate

basement rocks. Thus, geophysical and outcrop studies provide limited information on

the nature of basement units (Hills, 1984). A gravity high associated with the Central

Basin Platform is attributed to layered mafic intrusions of Precambrian age (Adams and

Keller, 1996). Subaerial exposure during the early to mid-Cambrian resulted in erosion

and nondeposition prior to the onset of sandstone deposition at the end of the Cambrian

(Miall, 2008). In the Late Cambrian to Early Ordovician a northwestward transgressing

sea occupied the area, depositing strata primarily composed of sandstone and limestone,

which are mostly the carbonates of the Ellenburger Group (Adams, 1965). The

Ellenburger contains limestone and dolomite members and constrains the lateral extent of

the Tobosa Basin (Frenzel et al., 1988). During the Middle Ordovician, the Simpson

Group was deposited. It consists of alternating layers of limestone, sandstone, and dark

green shale, and does not thin over the Central Basin Platform, which was already present

in Early Ordovician time. This lack of thinning has been attributed to either a quiescent

period or increased subsidence of the uplift relative to the Tobosa Basin (Frenzel et al.,

1988). The Simpson Group is overlain by the Montoya Formation, consisting of chert

and finely crystalline carbonates. Clasts at the base of the Montoya are derived from the

Simpson Group indicating an unconformity surface, although the extent of the erosional

surface is unknown (Galley, 1958; Frenzel et al., 1988). During the Silurian and Early to

6

Middle Devonian, carbonate deposition occurred on shelf areas, with shale forming in the

deeper parts of the basin. In the late Devonian-Early Mississippian, the strata that

constitute the Woodford Shale were deposited in shallow anaerobic waters from a

transgressing sea, forming sediments with a high organic content (Hills, 1984).

Overlying the Woodford Shale is a carbonate formation commonly referred to as

“Mississippian Lime” or Lower Mississippian (Broadhead, 2009). This formation was

deposited in early to mid-Mississippian. During the Mississippian, much of the southern

North American continent was covered in a shallow, tropical epicontinental sea with an

extensive carbonate platform (Gutschick and Sandberg, 1983). The northern portions of

the Permian Basin were located on the outer margin of the platform and the southern

extent has been placed in northeastern Andrews County (Fig. 2) (Bay, 1954). Minimal

clastic input, coupled with warm tropical waters promoted carbonate buildups on the

margins, with the extent of these carbonate buildups being largely controlled by the

advancing Gondwana plate (Ruppel and Kane, 2006). In the Midland Basin, upper

Mississippian units were deposited as fine-grained clastic sequences containing

interbedded carbonates. Proximal to the shelf margins, shale comprises the majority of

strata deposited during Osagean-Merameacian time, while carbonate deposition

dominated during the Chesterian (Hamilton and Asquith, 2000). Distal to the shelf

margin, hemipelagic shale predominates the Mississippian units, with carbonate debris

transported episodically to the basin. In the mid-late Mississippian, the outer portions of

the advancing Ouachita trough had been uplifted, resulting in siliciclastic sediment being

shed off northward into the basin (Ruppel and Kane, 2006).

7

New

Mex

ico

Texa

s

CHAVES

EDDY LEA

YOAKUM TERRY

GAINES

ANDREWS

C h e s t e r i a nS h e l f

C h e s t e rS h e l fC. Erosion

C. Erosion

C. E

rosio

n

N

0 5 10

miles

Permian BasinPre-Pennsylvanian

Chester Lm. Subcrop

New Mexico

Texas

WINKLER ECTOR MIDLAND

MARTIN

DAWSON

LOVING

C h e s t e r i a nS h e l f

Chesterian Basin

Absent

104 0’0’’W 103 0’0’’W 102 0’0’’W

104 0’0’’W 103 0’0’’W 102 0’0’’W

33 0

’0’’N

32 0

’0’’N

33 0

’0’’N

32 0

’0’’N

Figure 2. Map showing the approximate location of Late Mississippian (Chesterian) shelf. Subsequent erosion over the Central Basin Platform is shown. Dashed red square outlines the study area. Figure is modified from Hamilton and Asquith (2000).

8

The Tobosa Basin ceased to be a single depositional entity in the Early

Pennsylvanian, a result of uplift of the Central Basin Platform, and the subsequent

subsidence of the Delaware and Midland Basins (Ye et al., 1996). The Strawn, Canyon,

and Cisco Formations are present above the late Mississippian-early Pennsylvanian shale

sequence in the Midland Basin. The dominant feature of the Pennsylvanian geology in

the Midland Basin is the Horseshoe Atoll, formed by sequences of Strawn, Canyon,

Cisco, and early Permian carbonates. An increase in subsidence in the latter stages of the

Pennsylvanian promoted the buildup of carbonates along the basin edges, deterring

clastic sedimentation in the basin and resulting in a starved basin environment (Adams et

al., 1951).

During the Permian, subsidence continued with average rates of subsidence,

exceeding 200 m/Ma (Scholle, 2006). Permian strata within the Permian Basin are

characterized by an overall progradation of various types of depositional environments

including sabkhas, open marine shelves, and shelf-edge organic buildups (King, 1948;

Frenzel et al., 1988; Miall, 2008; Scholle, 2006). In the Midland Basin, sediment gravity

flow processes and submarine fan systems carried sand, shale, and carbonates into the

basin (Scholle, 2006). The later stages of the Permian (Ochoan) are marked by the

initiation of a barred basin to the west and the subsequent deposition of thick evaporite

deposits (Miall, 2008).

As a result of a sustained oceanic regression following the end of the Permian,

substantial amounts of Upper Permian strata (hundreds of feet/meters) were eroded

(Hills, 1984). Triassic deposition resulted in the formation of continental red beds in both

9

the Midland and Delaware basins. Jurassic and Lower Cretaceous rocks are present in

the basins, presumably the result of subaerial exposure (Hills, 1984). Upper Cretaceous

limestone and sandstone are also present. In the Tertiary, uplift associated with Basin-

and-Range deformation caused the western side of the Permian basin to be exhumed,

resulting in the present exposures along the western margins of the Delaware Basin.

Study Area and Methods

The study area is located in the central portion of the Midland basin, covering

approximately 25 mi2 (65 km2, Fig. 3). The area includes the southeastern portion of

Andrews County, the northeastern portion of Ector County, the northern region of

Midland County, and the southwestern region of Martin County. It extends from the

basin axis to the eastern flank of the Central Basin Platform. 130 well logs from wells

that penetrate all or portions of the Mississippian section were used in this study. Well

logs from the Fasken Fee BM #1 SWD well, located in the southern region of the study

area served as the type log (Fig. 3).

A three-dimensional seismic volume covering a portion of the study area (Fig. 3)

was interpreted to increase control on structure maps. Thirteen wells are present

containing sonic logs (Δt) in the confines of the seismic survey. Synthetic seismograms

were generated using a Δt log, and then paired with the actual seismic trace at the well

location. The synthetics were stretched and squeezed using anchor points to accomplish

as high a correlation match as possible. However, not all subdivisions contained

sufficient acoustic impedance to warrant picking (see below). Horizons that did were

gridded and then converted to depth to be incorporated in the construction of structure

10

Figure 3. Map showing the location of the study area within the Midland Basin. Map also depicts the location of the type log (green star) and cross sections constructed for the study. See table 1 for the wells used in constructing the cross sections. White stars correspond to wells from palynology data was obtained.

11

Table 1. Wells used in the construction of cross sections. Type log highlighted in yellow. Asterisk (*) corresponds to wells with available palynology data. AOIL-Abandoned oil well, SWD-Salt water disposal well.

Well UWI (API Num.) County Well Name Well Number Operator WELL TD Status1 42-003-4006800 ANDREWS MABEE RANCH 14 1 FASKEN OIL AND RANCH LTD 13370 OIL2 42-003-3077900 ANDREWS FASKEN BLK /BB/ 2 MOBIL OIL CORP 13500 AOIL3 42-003-1031100 ANDREWS FASKEN DAVID AZ 1 PAN AMERICAN 13600 DRY4* 42-003-4216900 ANDREWS FEE BM 1 SWD FASKEN OIL AND RANCH LTD 14200 SWD5 42-329-3126400 MIDLAND CASSELMAN 4 1 U S OPERATING INC 13675 AOIL6 42-329-3131700 MIDLAND FASKEN 4015B FASKEN OIL AND RANCH LTD 13520 OIL7 42-329-3128400 MIDLAND SCHARBAUER 2-27 ENDEAVOR ENERGY RESOURCES LIMITED PR13352 OIL8 42-135-1071100 ECTOR SUPERIOR-RATLIFF 1 FASKEN DAVID 13335 AOIL9* 42-135-4134700 ECTOR FEE BL 1 FASKEN OIL AND RANCH LTD 14568 SWD10 42-135-3458900 ECTOR FASKEN 16 1 ANSCHUTZ CORP 13758 DRY11 42-329-0200600 MIDLAND FEE X 1 DAVID FASKEN 12714 AOIL12 42-317-3282600 MARTIN COWDEN 1 L & B OIL CO INC 13570 AOIL13 42-329-3118100 MIDLAND GETTY-FASKEN 1-19 ANSCHUTZ CORP 13697 AOIL14 42-329-3148600 MIDLAND BARRON 414 EXXON CORPORATION 12128 AOIL15 42-329-3151400 MIDLAND FASKEN D 613 EXXON CORPORATION 11700 AOIL

12

maps. Structure contour maps were constructed to show depths to the top of the

Woodford Shale and Mississippian divisions. Isopach maps and cross sections were

constructed to decipher patterns of sediment accumulation in the area.

Cuttings taken from the Fasken Fee BM #1 SWD well were submitted to Gerald

Waanders (Independent Palynologist) for palynological analysis. The ability to assign a

tentative age to the strata aids in the overall depositional interpretation as Late

Mississippian to Early Pennsylvanian paleogeography varied. In addition to cuttings,

GeoSystems LLP. completed X-Ray diffraction analyses and determined the total organic

carbon (TOC) content on nine side wall cores. XRD analyses quantitatively apply weight

percent values to various mineral phases, and offers insight into clay type present in the

strata.

Division of Mississippian Strata

“Mississippian”, as used in this study, corresponds to the strata extending from

the low gamma ray response denoting the top of Silurian-Devonian carbonates to the

lowermost portion of the overlying “Atoka Lime” carbonate (Pennsylvanian) (Fig. 4).

On seismic, the Woodford is expressed as a trough, overlying a sharp peak denoting the

top of the Silurian-Devonian carbonates (Fig. 5). A limestone formation commonly

referred to as the “Mississippian Lime” or “Lower Miss” is present atop the Woodford

Shale Formation (Ruppel and Kane, 2006). The top of the Mississippian Lime is denoted

by an abrupt suppressed gamma ray response, a function of the carbonate present beneath

the overlying shale. On seismic, the Mississippian Lime appears as a basal portion of a

peak. The remaining section between the Mississippian Lime and Atoka Lime is deemed

13

Figure 4. Type log showing stratigraphic subdivisions utilized. Purple triangles denote sidewall core locations

420034216900

FASKENFEE BM1 SWD

TD : 14,200ELEV_KB : 3,009

0 100GR [API]

100 200GR [API]

0.2 2000ILD [ohmm]

1080

011

000

1120

011

400

1160

011

800

1200

012

200

1240

0

M i

s s i

s s i

p p

i a n

Dev

onia

nP

e n

n s y

v a

n i

a n

Barn

ett S

hale

WoodfordShale

Strawn

Devonian Carbonates

P a

l

e

o z

o

i

c

Low

er B

arne

tt

Mississippian Lime

Upp

er B

arne

tt

Upper Penn. Shales

U.B.2

U.B.1

U.B.3

U.B.4

U.B.5

U.B.6

L.B.1

L.B.2

L.B.3

“Atoka Lime”

Formation

Era

Serie

s

14

Figure 5. Synthetic seismogram for the Mississippian section displaying horizons incorporated in the construction of structure maps.

15

Barnett Shale, which can be further subdivided into an upper and lower section.

Extending from the “Mississippian Lime”, the lower Barnett is on average 180 feet (55

meters) thick, is characterized by high gamma ray measurements and is associated with

resistivity spikes (>10 Ωm). The lower Barnett was divided into 3 subdivisions (L.B.1

through L.B.3). L.B.1 lies directly above the Lower Mississippian. The top of L.B.1 is

expressed by a thin (<10 feet, 3 meter) occurrence of a low gamma ray excursion along

with an abrupt decrease in resistivity. L.B.2 is an overall fining upward succession that

culminates with both a sharp increase in gamma ray (>180 API) and resistivity (>150

Ωm) values. The top of the lower Barnett, L.B.3 is expressed as a sharp gamma ray peak

coupled with a resistivity excursion on the order of 90-200 Ωm. The top of the lower

Barnett is shown to have a trough for a seismic signature.

The upper Barnett section is divided into six intervals (U.B.1 through U.B.6) on

the basis of clean gamma ray signatures, representative of an amalgamation of silty

bioclastic debris encased in shale. Overlying the lower Barnett, U.B.1 is comprised of a

calcareous-siliceous shale sequence the top of which is denoted by an excessively high

GR and resistivity excursion of >160 API and 90 Ωm, respectively. U.B.2 and U.B.3

comprise the thickest intervals in the upper Barnett, and display a coarsening upward,

funnel shaped gamma ray electrofacies, along with a spike in resistivity. U.B.2 is

representative of a small trough on seismic. U.B.4 and U.B.5 are thinner, yet still

maintain a pronounced clean gamma ray and associated resistivity spike. U.B.4 contains

a strong peak as a seismic signature. The U.B.6 is picked by a subtle clean kick in the

gamma ray response associated with a resistivity spike and the top of a peak on seismic.

16

Overlying the Barnett is a formation termed “Atoka Lime”, equivalent to the “Bend

Group” (Wright, 2006).

Lithology

Nine sidewall cores from the Mississippian section in the Fasken Fee BM #1

SWD well were submitted to GeoSystems for X-ray diffraction (XRD) analysis (Fig. 4;

Table 2). Eight cores were from the upper Barnett interval, specifically the U.B.5, U.B.3,

and U.B.2 intervals, with the remaining core taken from the lower Barnett. All but one

core from the upper Barnett was taken from the sections coinciding with the cleaner

gamma ray values.

U.B.5 is a light gray, sandy, fossiliferous, coarse-grained dolostone (Fig. 6).

Layering is observed in the form of variations in grain size, and in the semblance of

bioclastic grains. Bioclastic grains are moderately sorted and include fragmented

brachiopods and echinoderms with a size greater than 1.0 mm. Fragmentation of the

carbonate constituents in the U.B.5 as well as the underlying subdivisions supports the

notion that these bioclasts have been transported from their original environment of

deposition. Apatite is present in the sample (9 weight %) in the form of replaced bone

fragments as well as nodular form. Total clay content derived from XRD is around 3

weight %, equally comprised of illite, kaolinite, and chlorite. Quartz comprises 22 weight

% of the sample. Carbonate minerals include ferroan dolomite (52 weight %) and 12

weight % of calcite (Table 2).

The sample taken from U.B.3 is comprised of a dark gray oolitic carbonate

grainstone (Fig. 7). XRD results show that the rock contains 85% carbonate by weight

17

Tabl

e 2.

X-r

ay d

iffra

ctio

n da

ta fo

r the

Fas

ken

Fee

BM

SW

D #

1 sh

owin

g w

eigh

t % o

f var

ious

min

eral

s pr

esen

t. S

ee F

igur

e 3

for l

ocat

ion

of w

ell,

and

Figu

re 4

for i

nter

vals

sam

pled

Geo

Syst

ems L

LP

X-R

AY

DIF

FR

AC

TIO

N A

NA

LY

SIS

Fee

BM

No.

1 S

WD

Wel

l

CL

AY

MIN

ER

AL

S O

TH

ER

MIN

ER

AL

S C

AR

BO

NA

TE

MIN

ER

AL

S D

RIL

LIN

G M

UD

SO

LID

S T

OT

AL

S

SAMPLE DEPTH (Ft)

SMECTITE

ILLITE-SMECTITE

ILLITE

KAOLINITE

CHLORITE

REICHWEITE ORDERING

ILLITE-SMECTITE EXPANDABILITY %

QUARTZ

K-FELDSPAR

PLAGIOCLASE

PYRITE

ANHYDRITE

APATITE

FERROAN DOLOMITE

CALCITE

DOLOMITE

SIDERITE

OTHER CARBONATES

BENTONITE

HALITE

BARITE

OTHER SOLIDS

TOTAL CLAY MINERALS

TOTAL OTHER MINERALS

TOTAL CARBONATES

TOTAL DRILL SOLIDS

SAMPLE NUMBER

1147

7 <

11

11

R0

20

22

<1

29

52

12

333

64

0

003

1162

5

<1

<1

3

R0

25

6

4 1

1

7 75

3

3 12

85

0

006

1166

2 1

21

<1

R0

15

19

21

468

2

422

74

0

008

1166

5

3 5

<1

1 R

0 20

42

2 1

<

1 4

35

7

9

45

46

0 00

9

1166

9 1

41

<1

R0

20

45

31

1<

15

27

12

650

44

0

010

1167

7

6 6

2 3

R0

30

53

<1

1 2

1

5 19

2

17

57

26

0 01

1

1168

3 4

47

6R

020

46

2

2<

12

27

21

50

29

001

3

1172

4

5 20

6

7 R

0 20

19

1

3 4

9

6 17

3

38

36

26

0 01

5

1194

6 8

46

45

R0

20

28

13

41

<1

<1

<1

63

37

Tr

001

8

R

eich

wei

te is

the

pro

babi

lity

that

in m

ixed

laye

r cl

ay, g

iven

a la

yer

of c

lay

A, t

he a

djac

ent

laye

r is

cla

y B

.

R

= 0

is a

ran

dom

mix

ing

of la

yers

R

= 1

is s

hort

ran

ge o

rder

ing

R =

3 is

long

ran

ge o

rder

ing

L.B

U.B.2

U.B.3

U.B.5SUB-UNIT

18

Figure 6. Photomicrograph representative of the sample taken from the U.B.5. Components include quartz grains (e.g., D6), and a range of bioclastic fragments. Fragments include brachiopods (e.g., G5), bivalves (e.g., A11), and echinoderms (e.g., F3).

Figure 7. Photomicrograph of the fossiliferous ooid grainstone of the U.B.3. Abundant ooids are present (e.g., E6, H6) as well as brachiopod fragments (e.g., B11).

______________________________________________________________________________________________________GeoSystemsLLP � 1410 Stonehollow Drive � Kingwood, Texas 77339

2662-853 )182( :enohP � Fax: (281) 358-3276

Thin Section Description

Plate 1A

Plate 1B

Company: Fasken Oil and Ranch, Ltd.Well: Fee BM No. 1 SWDCounty: AndrewsState: TexasDepth (Ft): 11477Sample No.: G2142-003

Plate A - Low magnification view displaying the range of components in this rock. Terrigenous very fine to medium sand quartz grains (D-6, H-13) are moderately sorted and angular to subangular in shape. Bioclastic fragments were primarily derived from brachiopods (G-5), though bivalve (A-11) and echinoderm (F-3) debris is also present. Phosphatic nodules are common (M-13). Porosity is not observed due to complete cementation. Coarse ferroan dolomite cements the rock and partially to completely replaces bioclasts. The type and degree of replacement is not consistent. Some echinoderm fragments are completely replaced, whereas others are completely unaffected. Partial replacement is observed in some fragments. Where replacement is complete (B-4), ferroan dolomite is commonly observed displaying unit extinction consistent with replacement of a unit calcite crystal in the original grain. Quartz displays similar heterogeneity in type and degree of replacement of brachiopod fragments.

Plate B - High magnification view displaying variations in replacement fabrics of brachiopod debris. Original grain composition is calcite (stained pink, D-5). Quartz cement nucleating on detrital grains (H-10) partially replacing the grain (D-8 to F-13). Ferroan dolomite has replaced the remainder of the bioclast. Retention of original lamellar fabric (F-16, difficult to view at this magnification) confirms the replacement. Etched grain margins of an unknown calcareous bioclast (B-14) are observed locally where replacement is by ferroan dolomite.

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18


2662-853 )182( :enohP � Fax: (281) 358-3276


Plate 5A

Plate 5B


Plate A - Low magnification view of a fossiliferous, ooid-pelletal grainstone. Lacking early marine cement stabilization of sediment fabric, interparticle porosity was reduced as soft, micritic pellets were deformed by early burial compaction. Ooids (aragonitic) exhibit significant micritization of outer rims by marine endolithic algae (H-6). In contrast, brachiopod fragments (B-9) are composed of calcite that resisted micritization.

Plate B - High magnification view displaying allochemical grains (partially micritized ooids, I-3, C-13 and possible ostracode valve, D-10). Very fine calcite spar cement occludes most interparticle voids (C-15, H-6). Locally, dolomite is observed partially replacing grains (H-12, K-14).

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

19

(Table 2) that occurs predominantly in the form of calcite present in ooids and as

intergranular cement. A more diverse faunal assemblage is present than in the U.B.5,

including ooids, brachiopods, echinoderms, bryozoans, ostracods, and bivalves (Fig. 7).

Overall the interval is well sorted with grains ranging from 0.08-0.11mm. Terrigenous

material in the cores of the ooids makes up 10 weight % of the rock (6 weight % quartz

silt and 4 weight % plagioclase). Chloritic clays constitute 3 weight % of the rock.

Five samples were chosen from the U.B.2 section, which reveals that the clean

GR response is the result of a fine-grained, dark gray limestone interval (Figs. 8 and 9).

Extensive bioturbation in the interval could have aided in the destruction of any bedding

structures present at time of deposition. Observed faunal elements are similar to the

overlying detrital sections consisting of bivalves, ostracods, echinoderms, and ooids.

Carbonate minerals (by weight %) account for a majority of the rock. Carbonate is

present as calcite, dolomite, and ferroan dolomite. Though abundant, carbonate

decreases with depth from 74% to 29%. Terrigenous mineral phases are also pervasive in

the rock with quartz comprising 19-53% of the rock by weight. Trace amounts of

plagioclase silt (1-3% by weight) are also present. Clay content accounts for 5-21weight

% of the rock and increases with depth. Clay is present in the form of illite-smectite (1-

21%), illite (2-6%), kaolinite (1-7%), and chlorite (1-6%).

The basal portion of U.B.2 is a poorly sorted calcareous and phosphatic shale

(Fig. 10). Compared to the overlying strata, this section contains higher clay content (38

weight %), including illite (20%), chlorite (7%), kaolinite (6%), and some mixed layer

illite-smectite (5%). Terrigenous constituents account for approximately one quarter of

20

Figure 8. Photomicrograph of sample taken from the U.B.2 displaying a large bivalve fragment (D8) as well as siliciclastic grains (e.g., E6).

Figure 9. Photomicrograph of sample taken from the U.B.2 showing a stylolite (C3-C18) separating two distinct textures of rock. An argillaceous texture is found above a more siliciclastic, silt-rich carbonate texture.


2662-853 )182( :enohP � Fax: (281) 358-3276


Plate 12A

Plate 12B


Plate A- Low magnification view displaying abundant siliciclastic and carbonate grains supported by a carbonate mud (micrite) matrix that is now recrystallized to coarser calcite and partially silicified. Locally, incipient stylolites are observed (F-4, K-11). Light bitumen stain occurs throughout, though microporous peloids may be heavily stained (I-3, L-7). A large bivalve fragment lies parallel to bedding (C-8).

Plate B - High magnification view displaying the prismatic structure of a bivalve fragment as well as grain and matrix characteristics. Rounded glauconite grains (I-15, K-17) and framboidal pyrite (black, I-10) are present in trace amounts.

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18


2662-853 )182( :enohP � Fax: (281) 358-3276


Plate 16A

Plate 16B


Plate A - Low magnification view displaying contrasting textures of the rock separated by an incipient microstylolite (C-3 to C-18). Above the stylolite, filamentous kerogen fragments (A-8, A-14) are common and the rock matrix contains more argillaceous material. Below, the rock is a cemented carbonate grainstone. Siliciclastic silt and carbonate grains float in the “micro-grainy” portion of the rock (poikilotopic celestite cement, F-8).

Plate B - High magnification view of the rock. The original carbonate mud (micrite) matrix is now recrystallized to very fine calcite spar. Allochems include glauconite (M-9), kerogen/bitumen stain (brown, F-5), quartz silt (A-10) and poorly preserved biotic debris (L-3). Note the occurrence of framboidal pyrite (small round black specks).

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

21

Figure 10. Photomicrograph of sample taken from the basal portion of the U.B.2 displaying a dark clay rich matrix with scattered bioclastic fragments (e.g., A16, B5).


2662-853 )182( :enohP � Fax: (281) 358-3276


Plate 28A

Plate 28B


Plate A - Low magnification view displaying the dark, clay-rich matrix supporting a variety of grains including bivalve fragments (B-5, B-16), agglutinated forams (E-18) and phosphate nodules (brown, E-12, K-9). Though no laminations are observed, bedding is defined by parallel orientation of elongate grains and compacted phosphatic nodules.

Plate B - High magnification view displaying bioclastic fragments (white) and internal components of a phosphatic nodule (H-3). In many nodules, type, size and spatial arrangement of contained fragments is identical to that of the enclosing matrix, indicating nodule enlargement by replacement of matrix clay.

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

22

the rock by weight. Quartz comprises 19 % weight and minor amounts of plagioclase

(3%) and potassium feldspar (1%) are present. Carbonate minerals also comprise ~25%

of the rock. Calcite in the form of bioclastic debris and as fossil fragments comprises 17

weight %. Dolomite (3%) and ferroan dolomite (6%) are also present as artifacts of

diagenesis. Other minerals that formed as a result of diagenesis are apatite (9 weight %)

and pyrite (4 weight %). Unpublished mudlogs have previously attributed this portion of

the U.B.2 coinciding with the elevated gamma ray and resistivity response as being a

coal. This interpretation, however, appears unlikely. The bulk density for a coal is

typically 1.2-1.8 g/cm3 (Serra, 1990), whereas in the study area, bulk densities for the

section of interest are on the order of 2.3-2.4 g/cm3.

The sample taken from the lower Barnett is a silty shale (Fig. 11). Clays dominate

the rock and comprise 63 weight %. Illite is the most prevalent clay mineral (46%) with

the remainder comprised of mixed layer illite-smectite (8%), chlorite (5%), and kaolinite

(4%). Terrigenous components account for little of the overall weight percent with only

plagioclase (3%) and potassium feldspar (1%) present. Quartz makes up 28% of the rock

primarily as a result of recrystallization. Carbonates are scarce in the lower Barnett with

ferroan dolomite the sole phase present contributing <1 weight %.

Geochemistry

The same samples subjected to XRD were also analyzed for total organic carbon

(TOC) content. Samples taken from the upper Barnett contain relatively low values (<1

weight % TOC), although an overall increase is seen with depth from 0.04-0.38 weight %

(Table 3) (Fig. 12). The overall dearth of TOC present in the upper Barnett samples is

23

Figure 11. Photomicrograph of sample taken from the L.B.3 showing the overall texture of the rock. Bioclasts (e.g., B17) are scarce. Light horizontal masses are clay probably from the backfill of feeding traces.

Table 3. Rock-Eval pyrolysis data for the Fasken Fee BM #1 SWD well.


2662-853 )182( :enohP � Fax: (281) 358-3276


Plate 32A

Plate 32B


Plate A - Low magnification view displaying textural and fabric elements typical of this rock. Bioclasts (C-17) are locally replaced by phosphatic material. Agglutinated foraminifera (B-13, D-6) are typically recrystallized to chert (microcrystalline) quartz. Some agglutinated foraminifera contain authigenic pyrite in the remnants of the internal chamber (J-10). Light colored lensoid masses are predominantly clay, and represent back fill in horizontal feeding traces.

Plate B - High magnification view displaying the rock matrix and flake-like clay fragments within horizontal burrows (G-10, F-17). Early diagenetic pyrite displays compactional deformation of laminae around the mass (D-15). Agglutinated foraminifera (F-4, I-3) are common.

ABCDEFGHIJKLM

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

24

Figure 12. TOC (weight %) vs. depth (MD)

0 20 40 60 80 100

11,400

11,500

11,600

11,700

11,800

11,900

12,000

12,100

0 2 4 6 8 10

Mea

sure

d D

epth

, MD

(ft)

Total Organic Carbon (wt% HC)

TOC % Carbonate

% Carbonate

GoodPoor Fair Excellent

TOC vs. Depth (MD)

25

expected, in that they were taken from mass gravity deposits comprised of carbonate

debris, not an organic rich mudstone. The basal portion of the U.B.2. contains 4.65

weight %, whereas the lower Barnett contains the highest TOC value among the samples

(5.3 weight %). These values overlap with values ranging from 1.1-4.7 weight % TOC

south of the study area (Candelaria, 1990). In the neighboring Delaware Basin, TOC

values have been found to be on the order of 4.4 weight % (Kinley, 2006).

As part of the Rock-Eval Pyrolysis, samples were heated to determine how much

petroleum has already been generated and how much generation potential is remaining.

At approximately 572°F (300°C) previously generated hydrocarbons in the source rock

are expelled creating a peak and the content of the hydrocarbons coinciding with the

numbers C1-C25 are recorded. The values for S1 correspond to the area beneath the

peak, representative of hydrocarbons that have already been produced in the rock and

failed to migrate out (Bjorlykke, 2010). A subsequent peak (S2) forms as the sample is

subjected to 1022°F (550°C). This second peak represents the samples ability to continue

to generate hydrocarbons.

Samples taken from the gravity flows contained paltry S1 values ranging from

0.04 to 0.29 mg HC/g (Table 3) (Fig. 13). S2 values for the upper gravity-flows are also

low, while increasing with depth from 0.11 to 0.67 mg HC/g. Samples taken from the

U.B.2 and the lower Barnett Shale contain heightened values. The U.B.2 shale sample

has a S1 value on the order of 3.56 mg HC/g, and an S2 value of 5.57 mg HC/g. The

lower Barnett contains the highest S1 value (4.88 mg HC/g) out of all samples and an S2

value of 5.45 mg HC/g.

26

Figure 13. Oil potential (S2) vs. Depth (MD)

11,400

11,500

11,600

11,700

11,800

11,900

12,000

12,1000 5 10 15 20

Mea

sure

d D

epth

, MD

(ft)

Oil Potential S2 (mg HC/g)

Good - ExcellentPoor Fair

Oil Potential S2

27

TOC Estimation

TOC content can be obtained indirectly from the inverse relationship of the

gamma ray (GR) and true resistivity (Rt) curves (Heslop, 2010). This method was used to

estimate TOC rich sections in the study area. The method calls for the curves to be

plotted on the same track with one of the scales reversed. In a non-source shale (TOC

lean) the curves tend to track, whereas in a source shale (TOC rich) separation of the

curves will occur. The separation is achieved because both of the logs increase in value.

A GR scale of 175-50 API units and a resistivity logarithmic scale of 0.5-500 Ωm

were applied to wells containing suitable curves. The results reveal that the upper

Barnett section is relatively TOC lean, whereas the greater separation between the two

curves in the lower Barnett section suggests higher TOC concentrations (Fig. 14).

To apply a quantitative value to the degree of separation the following formula,

modified from Heslop (2010) was used (Fig. 14):

Equation 1: TOC= (ΔGR+ΔRt)*30/(GRTOC + log10(RtTOC)),

where ΔGR and ΔRt are the separation of the curve from the base line, GRTOC is

representative of the respective log values present in the area of separation, and a value of

30 is applied to scale the separation. GRTOC and RtTOC are TOC values originally

calibrated to lab obtained TOC values.

28

Figure 14. Example of TOC estimates using the Heslop method described above. Notice how the curves track each other in the upper Barnett section, whereas separation occurs in the lower Barnett. TOT= Total gas content observed from the mudlog, HTOC= the TOC curve generated from equation 1.

420034216900

FASKENFEE BM1 SWD

TD : 14,200ELEV_KB : 3,009

0 100GR [API]

100 200GR [API]

1120

011

400

1160

011

800

1200

012

200

1240

0

M i

s s i

s s i

p p

i a n

Dev

onia

nP

e n

n .

Barn

ett S

hale

WoodfordShale

Devonian Carbonates

P a

l

e

o z

o

i

c

Low

er B

arne

tt

Mississippian Lime

Upp

er B

arne

tt

U.B.2

U.B.1

U.B.3

U.B.4

U.B.5

U.B.6

L.B.1

L.B.2

L.B.3

“Atoka Lime”

0.2 2000ILD [ohmm]

175 50GR [API]

0.5 500ILD [ohmm]

0 10HTOC

0 1000TOT [GU]

Formation

29

Age of Strata

Historically, fields producing from the bioclastic debris flows within the upper

Barnett have been reported as Mississippian (Chesterian) or Pennsylvanian (Atokan) in

age. R.V. Hollingsworth (Unpublished Paleontological Reports) identified the “Atoka

Lime” on the occurrence of Atoka fusulines. Underlying the “Atoka Lime”,

Hollingsworth placed the top of the Barnett Shale on the basis of a color change in

conjunction with a change in lithology, due to an absence of fusulines. Poor age

constraints promote ambiguity among operators when discussing the formation.

To reduce the uncertainty surrounding the age, samples from three wells were

submitted to Gerald Waanders (consulting Palynologist) for analysis. Cuttings were

collected from the Fasken Fee BM # 1 SWD, Fasken Fee BL#1 SWD, and the Amoco

David Fasken BS #1 wells. The BM and BS wells cuttings were compiled into 50 feet

(15 meters) increments, while the BL well had sample intervals of 60 feet (18 meters).

The occurrences of assemblages were paired with tops picked from logs. For the Amoco

David Fasken BS #1 well, open hole logs were only available through the U.B.2

formation and the remaining tops were picked from the mud log. The results reveal that

the Mississippian section in the study area encompasses the Chesterian, Meramecian,

Osagean, and possibly the Kinderhookian stages (Figs. 15, 16 and 17, Appendix 1).

30

Figure 15. Palynology results tied into the Fasken Fee BM #1 SWD well.

31

Figure 16. Palynology results tied into the Fasken Fee BL #1 SWD well.

32

Figure 17. Palynology results tied into the Amoco David Fasken BS #1 well.

33

The top of the U.B.6 was found to be conformable with the first occurrences of

Chesterian spores present in all three wells. The top of the Meramecian coincided with

the top U.B.3 to the base of the U.B.2. Osagean assemblages of spores were first

recorded around the shale marker denoting the top of the U.B.1 and encompass the

entirety of the U.B.1, lower Barnett section, and the upper portion of the Mississippian

Lime. Due to possible uphole contamination of samples, a tentative Kinderhookian age

was assigned to the basal portion of the Mississippian Lime and the entirety of the

Woodford Shale.

Sediment Accumulation

Isopach maps and cross sections show the patterns of sediment distribution and

accumulation. Thickness presented on maps and cross sections portray the thickness of

units following compaction. The Mississippian section ranges in thickness from

approximately 980 feet (300 meters) in the northwest to 720 feet (220 meters) in the

southeast (Fig. 18). Noticeable thinning of the section to 190 feet (60 meters) is observed

at the McRae Farm #2 well drilled on an anticlinal structure in the southwestern region of

the study area. The Mississippian Lime is thickest in the northwest, where it is 290 feet

(90 meters) thick (Fig. 19). Thickness decreases to approximately 80 feet (25 meters) in

the southeast. This thinning can be readily seen on cross sections along depositional dip

(Fig. 20). Thickness of the lower Barnett varies from 210 feet (65 meters) to 136 feet (20

meters) (Fig. 21). However, a gross isopach map for the entire lower Barnett interval

depicts thickness decreasing to the east, suggesting that a major depocenter was located

to the west.

34

Figure 18. Gross isopach map for the entire Mississippian section. The overall westward thickening, and the thinning over the McRae farm #2 well are readily apparent. Contour interval is 25 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

750775

775

800

800

800

825

825

8 25

528

528

52

8

850

850

850

058

850

058

578

875

875

875

578

875

578

900

900

900

900

009009

925

925

925

529

925

529

925

925

950

950

059

059

059

059

950

95

0

904

877

931

910

941

850

930

883

962

951907

845

920

942

885

936

961

932

976

938936

843832

824

722

911

895

862

795

854

779786

842

805899 820

794

830

888

796

871

797

843

830825

813

813

951

939

941

914

936

893

925934

972

965

867

976

756

970

969

32°00'N

102°25'W 102°20'W 102°15'W 102°10'W

32°0

0'N

102°05

32°05'N32

°05'

N32 °1 0'N

32°1

0'N

32 °1 5'N32

°15'

N

02°30'W 102°25'W 102°20'W 102°15'W

32°2

0'N

975950925900875850825800775750

Gross Mississippian

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

GROSS_MISSISSIPPIAN - GROSS_MISS_

CONTOURSGROSS_MISSISSIPPIAN - ISOPACH4/23 - Isopach Thickness

GROSS_MISSISSIPPIANISOPACH423.GRDContour Interval = 25

750

775

800

825

850

875

900

925

950

975

WELL SYMBOLSLocation OnlyOil WellDry HoleService WellAbandoned Oil WellShut In Oil Well

May 23, 2012

PETRA 5/23/2012 8:15:06 PM

35

Figure 19. Gross isopach map for the Mississippian Lime. Notice the overall southeastward thinning, which likely reflects the southward dipping shelf. Contour interval is 10 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

80

09

100

100

110

110

120

120

120

02

1

130

130

031

140

140

140

041

150

15

0

150

051

150

061160

160

160

170

170

170

180

180

180

190

190

190

19

0

200

20 0

200

200

210

210

21021

0

220

220

22022

0

230

230

230

230

240

240

240

240

250

250

250

250

260

260

260

260

270

270

072

280

280

280

266

249

280

246

228

204

223

245

254

221203

278

199

207

290

234

211

222

208

206192

161155

116

78

175

155

141

121

141

112112

127

129166 120

130

122

154

120

134

112

137

120121

122

265

197

238

246

239

251

240

251248

204

242

262

237

95

216

3002802602402202001801601401201008060

GrossLower Miss. Lime

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

LOWER_MISS - ISOPACH

CONTOURSLOWER_MISS - ISOPACH - Isopach Thickness

LOWER_MISSISOPACH.GRDContour Interval = 10

60 80 100

120

140

160

180

200

220

240

260

280

300


May 12, 2012

PETRA 5/12/2012 2:10:11 AM

Andrews

Ector

Martin

Midland102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N32

°15'

N

102°25'W 102°20'W 102°15'W

36

TD

: 1

3,3

70

EL

EV

_K

B :

2,9

58

TD

: 1

3,5

00

EL

EV

_K

B :

2,9

27

TD

: 1

3,6

00

EL

EV

_G

R :

2,9

18

TD

: 1

4,2

00

EL

EV

_K

B :

3,0

09

TD

: 1

3,6

75

EL

EV

_K

B :

2,9

12

TD

: 1

3,5

20

EL

EV

_K

B :

2,8

85

TD

: 1

3,3

52

EL

EV

_K

B :

2,8

80

<3

.41

MI>

<2

.50

MI>

<3

.22

MI>

<5

.16

MI>

<2

.04

MI>

<2

.06

MI>

11200 11400 11600 11800 12000 12200 12400 12600

10800 11000 11200 11400 11600 11800 12000 12200

11000 11200 11400 11600 11800 12000 12200 12400

11200 11400 11600 11800 12000 12200 12400

11000 11200 11400 11600 11800 12000 12200 12400

11000 11200 11400 11600 11800 12000 12200 12400

11000 11200 11400 11600 11800 12000 12200

U_B

_6

U_B

_5

U_B

_4

U_B

_3

U_B

_2

U_B

_1

L_B

_3

L_B

_2

L_B

_1

LO

WE

R

MIS

SIS

SIP

PIA

N

LIM

N

WO

OD

FO

RD

DE

VO

NIA

N

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

12

34

56

7

A’A Fi

gure

20.

Str

atig

raph

ic c

ross

sect

ion

A-A

’ alo

ng d

epos

ition

al d

ip, f

latte

ned

on th

e U

.B.6

show

s the

ove

rall

decr

ease

in M

issi

ssip

pian

lim

e th

ickn

ess w

ith d

ip.

See

Figu

re 3

for l

ocat

ion

of th

e se

ctio

n.

37

Figure 21. Gross isopach map constructed on the lower Barnett. The map shows a westward thickening. Contour interval is 10 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

135

5415

51

155

551

551

551

561

165

165

561

165

571

175

175

175

571

175

581

185

581

591

591

194

168

201

167

183

157

176

174

192

171178

137

172

162

209

195

178

194

173

174161

155153

154

163

158

165

146

157

156143

157

146155 137

152

153

162

156

162

160

153

152

158

154

158

136

192

162

189

189

198

196

193

192193

195

174

170

192

162

176

215205195185175165155145135

Gross Lower Barnett

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

LOWERBARNETT3 - GROSS_LOWER_BARNETT

CONTOURSLOWERBARNETT3 - GROSS_LOWER_BARNETT - Isopach Thickness

LOWERBARNETT3GROSS_LOWER_BARNETT.GRDContour Interval = 10

135

145

155

165

175

185

195

205

215


May 12, 2012

PETRA 5/12/2012 1:07:46 AM

Andrews

Ector

Martin

Midland102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

38

To differentiate between basinal, siliciclastic-rich, shale and bioclastic debris flow

strata in the upper Barnett, a cutoff of 14 Ωm is applied to the deep resistivity log (Fig.

22). Anything reading greater than 14 Ωm is taken to be representative of the more

permeable debris flow units, and anything less is considered “tighter” shale. It should be

noted, that a gamma ray cutoff would have been preferred, but due to various vintages of

gamma ray curves, displaying a wide range of values for the cleaner sections, a gamma

ray cutoff is misrepresentative of the debris flow section. A gross isopach map for the

upper Barnett section shows thickness increasing north to south (Fig. 23), suggesting that

the basin depocenter has slightly migrated to the south when compared with the

underlying lower Barnett. When the cutoff of greater than 14 Ωm is applied to the

section, a striking contrast is observed. With that cutoff, the section decreases from north

to south (Fig. 24), suggesting a northern source for the upper Barnett carbonate debris.

Cross sections along depositional strike also show an overall decrease towards the south

in the electrofacies representative of the carbonate debris (Fig. 25 and 26). Since

established production has been achieved from the U.B.2 bioclastic debris (see below),

gross and net isopach maps were also constructed for the U.B.2 (Fig. 27 and 28). Similar

patterns to the gross and net isopach maps for the upper Barnett emerge for the U.B.2.

While the gross isopach map for U.B.2 shows thickening to the south, the net isopach

map again shows a thick in the north and thin in the south. The pattern of the net isopach

maps suggests a northern source for the mass gravity flows.

39

Figure 22. Type log showing the >14 Ωm cutoff used to differentiate between shales and bioclastic debris flows. Shaded areas coincide with >14 Ωm.

42-003-42169

FASKEN1 SWD

TD : 14,200ELEV_KB : 3,009

0 100GR [API]

100 200GR [API]

0.2 2000ILD [ohmm]

1080

011

000

1120

011

400

1160

011

800

1200

012

200

1240

0

M i

s s i

s s i

p p

i a n

Dev

onia

nP

e n

n s y

v a

n i

a n

Barn

ett S

hale

WoodfordShale

Strawn Formation

Devonian Carbonates

P a

l

e

o z

o

i

c

Low

er B

arne

tt

Mississippian Lime

Upp

er B

arne

tt

Upper Penn. Shales

U.B.2

U.B.1

U.B.3

U.B.4

U.B.5

U.B.6

L.B.1

L.B.2

L.B.3

“Atoka Lime”

40

Figure 23. Gross isopach map for the upper Barnett. The map pattern suggests that the main depocenter has shifted slightly towards the south since the deposition of the lower Barnett. Contour interval is 25 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

004

524

524

524

450

450

054

054

054

574

574

574

475

574

500

500

500

500

500

525525

525

525

525

525

525

525

055

055

5 5 0

055

55 0

055

055

575575

575

575

444

460

450

498

530

489

530

464

517

558526

430

550

573

386

507

572

517

596

558582

527524

554

573

583

557

528

556

510532

558

530578 564

512

555

573

520

576

525

553

559

540

550

533

412

587

592

511

506

477

489

471

483493

573

549

435

547

499

471

558

625600575550525500475450425400

Gross Upper Barnett

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

GROSS_UPPER_BARNETT - GROSS_UPPER_BARNETT

CONTOURSGROSS_UPPER_BARNETT - GROSS_UPPER_BARNETT - U_B_6 [SLP] - L_B_3 [SLP] ISOPACH

GROSS_UPPER_BARNETTGROSS_UPPER_BARNETT.GRDContour Interval = 25

400

425

450

475

500

525

550

575

600

625


May 12, 2012

PETRA 5/12/2012 2:08:28 AM

Andrews

Ector

Martin

Midland102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

41

Figure 24. Net isopach map for the upper Barnett showing a southward thinning of strata. Contour interval is 10 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

20

20

02

03

03

03

04

04

04

04

05

50

50 50

50

06

06

06

06

06

06

07

07

07

07

07

07

07

80 08

08

08

08

08

08

08

08

90

90 90

09

9009

09

90

90

100

001

100

001

73

94

80

94

70

111102

64

67

86

56

34

22

52

5262

90

69

19

41

7545

18 17

36

2918

35

19

49

20

16

56

22

46

11

32

60

47

55

8048

5679

28

74

93

31

77

101

110

1101009080706050403020

Net Upper Barnett

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

GROSS_UPPER_BARNETTCO3 - GROSS>14

CONTOURSGROSS_UPPER_BARNETTCO3 - GROSS>14 - User Footage

GROSS_UPPER_BARNETTCO3GROSS14.GRDContour Interval = 10

20 30 40 50 60 70 80 90 100

110


May 12, 2012

PETRA 5/12/2012 2:35:21 AM

Andrews

Ector

Martin

Midland102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

42

TD

: 1

3,3

35

ELE

V_K

B : 2

,994

TD

: 1

4,5

68

ELE

V_K

B : 2

,969

TD

: 1

3,7

58

ELE

V_K

B : 2

,936

TD

: 1

2,7

14

ELE

V_K

B : 2

,913

TD

: 1

3,5

70

ELE

V_K

B : 2

,902

<4.6

7M

I><

1.8

1M

I><

3.1

8M

I><

4.4

1M

I>

10200 10400 10600 10800 11000 11200 11400 11600

10800 11000 11200 11400 11600 11800 12000 12200

11000 11200 11400 11600 11800 12000 12200

11200 11400 11600 11800 12000 12200 12400

10800 11000 11200 11400 11600 11800 12000

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

Gr

Res.

U_B

_6

U_B

_5

U_B

_4

U_B

_3

U_B

_2

U_B

_1

L_B

_3

L_B

_2

L_B

_1

LO

WE

R M

ISS

ISS

IPP

IAN

LIM

ES

TO

NE

WO

OD

FO

RD

DE

VO

NIA

N

BB’

89

1012

11

Figu

re 2

5. S

tratig

raph

ic c

ross

sect

ion

B-B

’, fla

ttene

d on

the

top

of th

e U

.B.6

,alo

ng

depo

sitio

nal s

trike

. N

otic

e th

e ov

eral

l thi

ckne

ss o

f the

U.B

.2 c

lean

GR

ele

ctro

faci

es.

For

loca

tion

of th

e se

ctio

n se

e Fi

gure

3.

43

Figure 26. Stratigraphic cross section C-C’, flattened on the U.B.6, along depositional strike showing an overall decrease in the clean GR sections for the U.B.2, which represents the bioclastic debris flows, when compared to cross section B-B’ located to the north. For location of the cross section see Figure 3.

TD : 11,700

ELEV_KB : 2,880

TD : 12,128

ELEV_KB : 2,870

TD : 13,520

ELEV_KB : 2,885

TD : 13,697

ELEV_KB : 2,916

<1.14MI> <1.13MI> <3.25MI>

11

000

11

200

11

400

11

600

11

800

12

000

12

200

11

000

11

200

11

400

11

600

11

800

12

000

12

200

12

400

11

000

11

200

11

400

11

600

11

800

12

000

12

200

12

400

11

000

11

200

11

400

11

600

11

800

12

000

12

200

12

400

U_B_6

U_B_5

U_B_4

U_B_3

U_B_2

U_B_1

L_B_3

L_B_2

L_B_1

LOWER MISSISSIPPIAN

LIMESTONE

WOODFORD

DEVONIAN

Gr Res. Gr Res. Gr Res. Gr Res.

C’ C1361415

44

Figure 27. Gross isopach map for the U.B.2 showing a northwestward thinning. Contour interval is 20 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

60

60

60 06

80

8 0

80

08

08

08

08

08

001

100

100

100100

10

0

100

001

100

100

021021

021021

021

120

041

041

140

041

0

41

061

160

160

081

71

114

88

108

48

46

58

52

94

8056

6253

99

67

124

73

84

170

157

169

145

159

160

159142

113117106

127

129

110

107

152

112 101

143

117

116

172

125

111114

115102

107

148

111

101105

103

118

91

96

112

101

150

82

90

81

96

77

9387

187

96

100

174

66

100

95154

76

137

32°00'N

102°25'W 102°20'W 102°15'W 102°10'W

32°0

0'N

102°05

32°05'N

32°0

5'N

32 °1 0'N

32°1

0'N

32 °1 5'N

32°1

5'N

02°30'W 102°25'W 102°20'W 102°15'W

32°2

0'N

18016014012010080604020

GrossU.B.2

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

UB2 - FINAL_ISOPACH

CONTOURSUB2 - FINAL_ISOPACH - Isopach Thickness

UB2FINAL_ISOPACH.GRDContour Interval = 20

20 40 60 80 100

120

140

160

180


May 23, 2012

PETRA 5/23/2012 8:12:56 PM

45

Figure 28. Net isopach map constructed for the U.B.2 showing a southward thinning. Contour interval is 10 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

00

10

10

10

01

10

20

20

20

20

20

20

2020

02

02

30

30

30 30

30

30 30

04

19

61

45

44

25

3323

25

28

29

7

21

2519

34

31

14

24

12

1816

5

615

9

2

0

2220

1725

18 21

42313

13

20

13

21

24

11

1616

913

11

22

56

21

22

32

32°00'N

102°25'W 102°20'W 102°15'W 102°10'W

32°0

0'N

102°05

32°05'N32

°05'

N32 °1 0'N

32°1

0'N

32 °1 5'N32

°15'

N

02°30'W 102°25'W 102°20'W 102°15'W

32°2

0'N

50403020100

Net U.B.2

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

MOONLIGHT_GROSS - MOONLIGHT>14

CONTOURSUBS1 - GROSS>14 - User Footage

UBS1net greater14.GRDContour Interval = 10

0 10 20 30 40 50


May 23, 2012

PETRA 5/23/2012 8:01:52 PM

46

Regional Context

Carbonates sourced from a platform in the north and shale deposited in a basin in

the south characterizes the two distinct lithologies present in Mississippian strata (Ruppel

and Kane, 2006) (Fig. 29). Carbonates were deposited up dip on a southwest- to west-

dipping shelf grading into deeper water limestone, progressively thinning basinward into

basinal shale that comprises the Barnett Shale Formation. The southernmost extent of the

carbonate platform is located north of the study area in Gaines and northern Andrews

Counties (Bay, 1954). The shelf has been eroded over the Central Basin Platform, but

remains present in central Lea County, New Mexico (Hamilton and Asquith, 2000).

Elsewhere in the basin, hemipelagic sedimentation dominated resulting in the formation

of siliceous shale. Maximum thickness of shale is recorded in portions of Reeves and

Ward County (Craig and Conner, 1979; Wright, 1979). The positive features of the

Diablo uplift and Pedernal Massif defined the southern and western limits of the basin

(Fig. 29) and provided the bulk of the siliciclastic sediment to the basin. Starting around

the mid-late Mississippian, uplifted portions of the advancing Ouachita trough also

served to provide siliciclastic input in the southern regions of the basin (Ruppel and

Kane, 2006).

Existing isopach maps for the Mississippian in the Permian Basin show a major

depocenter roughly corresponding to the locality of the ancestral Central Basin Platform

with strata thinning eastward (Fig. 29; Wright, 1979). The study area falls just shy of the

1000 feet contour line on the isopach map for Mississippian strata. Observed thickness in

the study for gross Mississippian strata is 975 feet (300 meters). The eastward thinning is

also reflected in the gross Mississippian isopach map for the study area.

47

Figure 29. Paleogeographic map showing the Permian Basin region during the late Mississippian. Isopach map shows a major depocenter corresponding to the western portion of the study area (yellow star). Contour interval is 250 feet. Map is after Wright (1979) and Ruppel and Kane (2006).

48

Structure of Study Area

Accumulation of Mississippian sediment varied minimally from that of the

Devonian, such that the major depocenters of the Tobosa Basin maintained their role

(Wright, 1979). During the Late Mississippian, the Tobosa Basin was subjected to

various structural changes, including the initial pulses of the Marathon-Ouachita orogeny.

The emergence of the Central Basin Platform during this time resulted in the division of

the Tobosa Basin into two separate depositional entities with the Delaware Basin to the

west and the Midland Basin to the east. Regionally, the Midland Basin displays an

asymmetric character, with the basin axis running approximately north-south, deepening

to the west.

Regional dip is steepest in the west along the flanks of the Central Basin Platform

and lessens to the east towards Martin County. Structure contour maps constructed on

the top of the Woodford, the top of the L.B.3.the U.B.2, and U.B.6 all reflect the same

overall geometry (Figs. 30-33). The measured depth to the top of the Mississippian

section in the study area ranges from 9,000 feet (2,750 meters) in the west to 11,500 feet

(3,500 meters) in the east. Locally, anticlinal and synclinal features are recognized in the

southern portion of the study area. These are presumably a by-product of the structural

regime changes associated with deformation along the flanks of the Central Basin

Platform.

49

Figure 30. Structure contour map of the top of the Woodford Shale. The map depicts a post-depositional low that trends north-south throughout the central portion of the study area. Contour interval is 100 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

1617

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

0049-

0039-

0039-- 93

00

0039-

- 9300

- 920

0

0029-

- 9200

0029

-

- 9200

- 9200

- 9 200

002

9 -

0029-

001

9-

- 910

0

- 910

0

- 9100

0019-

- 910

00019-

- 900

0

- 9000

- 900

0

-900

0

0009-

0009-

- 9000

-890

0- 8900

- 890

0- 8

900

0098-

- 8800

- 880

0-8

8 00

- 8700

- 870

0-8

700

- 8600

-860

0

0068

-

- 8500

-850

0

0058

-

- 8400

-840

0

0048

-

- 8300

-830

0

- 8200

-820

0

- 8100

-810

0

-8,124

-8,966

-8,074

-8,978

-9,261

-9,171-9,293

-8,987

-8,192

-9,284-9,251

-9,343

-9,114

-9,348

-9,152

-8,444

-8,976

-8,676

-9,262

-8,927-9,108

-8,931

-8,903

-9,072

-8,917

-9,306

-9,255

-9,174

-9,130-9,159

-8,979-8,987

-9,025

-8,974-9,274 -9,110

-8,970

-9,036

-9,267

-9,026

-9,264

-9,027

-9,220

-9,077-9,028

-9,143

-9,357

-9,094

-8,141

-8,116

-8,218

-8,102

-8,060

-8,188-8,111

-8,785

-9,118

-9,321

-8,433

-9,042

-9,316

-9,021

-8100-8200-8300-8400-8500-8600-8700-8800-8900-9000-9100-9200-9300-9400-9500

Woodford Structure Map

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

FMTOPS - WOODFORD[SLP] (SS) (FEET)

CONTOURSFMTOPS - WOODFORD May 3 - WOODFORD

FMTOPSWOODFORD Final.GRDContour Interval = 100

-950

0

-940

0

-930

0

-920

0

-910

0

-900

0

-890

0

-880

0

-870

0

-860

0

-850

0

-840

0

-830

0

-820

0

-810

0


May 11, 2012

PETRA 5/11/2012 7:54:33 PM

102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

50

Figure 31. Structure contour map of the top of the L.B.3. Folds are present in the eastern and southeastern portion of the area. Contour interval is 100 ft.

102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

- 890

0

- 8900

- 8900

0098-

0098-

0098-0098-

-890

0

- 880

0

0088

-

- 880

0

- 8800

-88 0

0

- 880

0

- 8800

00 88-

- 8800

- 8800

0088-

0088-

- 8800

- 8800

- 870

0- 8

700

0078

-

- 870

0- 8700

0078-

-8700

-870

0

0078

-

- 8600

- 860

0-8

600

- 860

0- 8600

0068-- 8

500

- 850

0-8

5 00

-850

0

- 840

0

- 840

0- 8

400

-840

0

- 830

0

- 830

0- 8

300

-830

0

- 8

200

- 820

0- 8

200

0028

-

- 810

0

- 810

0- 8

100

- 800

0

-800

0- 8

000

- 790

0

-790

0- 7

900

- 7800

-780

0

- 780

0

- 7700

- 770

0

- 770

0

- 760

0- 7

600

0057-

- 750

0

- 750

0

-740

0

- 7

400- 7300

-7,664

-8,550

-7,593

-8,565

-8,849

-8,810-8,894

-8,568

-7,747

-8,892-8,870

-8,928

-8,744

-8,979

-8,654

-8,015

-8,587

-8,261

-8,881

-8,547-8,755

-8,615

-8,595

-8,802

-8,967

-8,943

-8,863

-8,863-8,861

-8,710-8,733

-8,740

-8,699-8,953 -8,853

-8,688

-8,761

-8,951

-8,749

-8,968

-8,755

-8,930

-8,805

-8,871

-8,752

-8,863

-8,956

-8,590

-8,734

-7,714

-7,680

-7,781

-7,655

-7,638

-7,745-7,670

-8,387

-8,702

-8,889

-8,005

-8,784

-8,803

-8,923

-8,637

-7200-7300-7400-7500-7600-7700-7800-7900-8000-8100-8200-8300-8400-8500-8600-8700-8800-8900-9000-9100-9200

L.B.3 Structure Map

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

FMTOPS - L_B_3[SLP] (SS) (FEET)

CONTOURSFMTOPS - L_B_3 [SLP] - Top of Lower Barnett Shale

FMTOPSL_B_3SLP.GRDContour Interval = 100

-920

0

-910

0

-890

0

-870

0

-850

0

-830

0

-810

0

-790

0

-770

0

-750

0

-730

0


May 11, 2012

PETRA 5/11/2012 9:03:21 PM

Andrews

Ector

Martin

Midland

51

Figure 32. Structure contour map atop of the U.B.2 subdivision. Overall geometry is similar to the preceding maps. Contour interval is 100 feet.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

0098-

-880

0

0088-00

88-

- 870

0

- 870

0

007

8-

0078-- 8 700

- 8700

- 8700

-870

0

0078-

- 8700

0078-

0078-00

78-

- 860

0

- 8600

-860

0

- 8600-8

600

- 8

600

0068-

0068-

0 068-

- 8600

- 8600

0068-

006

8-

- 850

0

00

58-

- 8500

- 850

0

-850

0

- 8500

0058-

00

58-

0058-

0058-

- 8500

00

58-

- 8400

- 840

0-8

400

- 8400

0048

-

0048-

0048-- 8

40

0

- 830

0

-830

0- 8

300

0038-

- 820

0

-820

0

- 820

0

0028

-

- 810

0

-810

0

- 810

0

- 800

0

-800

0

- 800

0

- 7900

-790

0

- 790

0

- 7800

-780

0

- 780

0

- 770

0

-770

0

-770

0

- 7600

-760

0

0067

-

- 7500

- 750

0

- 7400

- 740

0

- 7300

- 730

0

- 720

0

- 7200

- 7100

- 7100

-7,350

-8,276

-7,273

-8,291

-8,552

-8,513-8,588

-8,328

-7,440

-8,617-8,633

-8,674

-8,604

-8,710

-8,605

-8,499

-8,688

-8,643

-8,449

-7,678

-8,258

-7,951

-8,565

-8,006

-8,199-7,959

-8,219-8,466

-8,363

-8,368

-8,388

-8,476

-8,697

-8,694

-8,631

-8,647-8,614

-8,484

-8,711 -8,642

-8,446

-8,700

-8,529

-8,689

-8,525

-8,693-8,649

-8,689 -8,637-8,659

-8,503

-8,653

-8,668

-8,638

-8,620

-8,713

-8,543

-8,682

-8,461

-8,663

-8,724

-8,734

-8,436

-8,437

-7,432

-7,395

-7,509

-7,359

-7,377

-7,446-7,396

-8,052

-8,425

-8,641

-8,694

-7,663

-8,736

-8,535

-8,579-8,654

-8,209

-8,642

-8,386

-8,421

-8,229

-8,329

-7100-7200-7300-7400-7500-7600-7700-7800-7900-8000-8100-8200-8300-8400-8500-8600-8700-8800-8900

U.B.2 Structure Map

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

FMTOPS - U_B_2[SLP] (SS) (FEET)

CONTOURSFMTOPS - U_B_2 [SLP] - MISS MOON PAY

FMTOPSU_B_2SLP.GRDContour Interval = 100

-890

0

-880

0

-870

0

-860

0

-850

0

-840

0

-830

0

-820

0

-810

0

-800

0

-790

0

-780

0

-770

0

-760

0

-750

0

-740

0

-730

0

-720

0

-710

0


May 11, 2012

PETRA 5/11/2012 9:49:49 PM

Andrews

Ector

Martin

Midland102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

52

Figure 33. Structure contour map of the top of the U.B.6 subdivision. Various folds are present in the eastern part of the study area. Contour interval is 100 ft.

3

25

12

21

28

27

22

11

6

1

7

10

23

26

2524

9

16

17

42

41

38

37

34

13

12

11

10

9

8

7

48

7

8

6

5

4

3

2

1

32

1

16

17

32

33

48

1

2

47

3431

18

15

2

43

36

3

14

19

30

35

46

45

36

29

20

4

3528

37

44

15

14

2

1

24

9

16

17

33

32

31

25

26

23

24

5

30

29

28

18

15

3

14

19

27

26

25

13

14

1224

23

22

20

13

4

5

12

21

21

20

191

2118

17

16

15

C5

20

27

22

5

11

2

22

19

17

18

25

26

27

20

21

2223

24

6

5

4

9

8

7

13

14

15

16

17

9

10

11

12

7

8

9

T1S

3

4

5

6

1

2

3

4

39

40

41

42

31

3233

34

27

28

29

30

31

32

33

28

29

30

19

2021

18

19

20

21

17

16

10

9

8

7

18

17

16

8

7

6

5

4

3

5

8

9

12

43

46

45

44

11

10

7

6

5

1

16

17

32

31

36

3231

18

15

2

4

3

14

19

30

33

34

29

2013

4

6

2

6

12

11

10

9

47

6

5

4

7

10

23

26

24

9

8

3

2

1

48

44

45

30

29

1

16

17

18

15

228

27

46

43

37

38

42

26

25

24

3

14

19

13

4

2322

21

41

39

35

40

20

19

18

17

5

12

11

6

47

16

9

841

40

25

32

33

48

1

16

38

37

36

32

31

15

2

4734

31

30

35

46

3

14

30

29

2423

13

4

45

3629

20

21

28

37

44

5

12

22

21

1514

13

9

8

7

22

10

23

6

5

4

12

11

10

3

2

1

3

19

18

13

14

15

16

7

8

9

10

11

12

7

8

5

6

1

2

3

4

5

33

3217

16

137

38

34

35

36

2

15

18

31

34

3530

19

14

3

25

2627

22

23

24

4

13

20

29

2821

12

5

13

1415

11

22

27

12

6

1

2

3

4

5

36

48

33

32

17

100 1/2

16

1

48

47

2

15

18

31

34

47

100

46

35

30

1914

3

46

36

45

4

13

20

29

36

45

4437

28

21

12

5

44

37

38

43

6

11

22

27

38

39

26

23

10

742

3924

25

40

33

28

16

9

110

25

43

2

11

12

1

2

3

4

5

6

1

48

43

4445

46

47

48

37

38

39

40

41

42

37

36

31

32

33

34

35

36

31

30

25

26

27

28

T1S29

30

25

19

20

21

22

23

2417

18

3

4445

46

47

38

39

40

41

42

37

38

35

3631

32

3334

35

26

27

28

29

30

25

26

23

2419

20

21

2223

24

13

14

15

16

17

18

13

12

7

8

9

10

116

1

19

18

13

14

15

16

7

8

9

10

11

12

7

6

1

2

3

4

5

6

43

44

45

46

47

4831

32

29

30

37

38

39

40

41

42

32

33

34

35

3619

28

29

20

21

16

17

8

9

4

5

33

34

27

28

3

10

10

25

13

24

23

13

12

1

9

9

1

8

15

14

11

2

4

3

2

21

22

15

16

3

11

10

10

11

2

35

26

20

4

9

9

3

4

34

22

0068-

0058-

0058-

005

8 -

0048

-

-840 0

0048-

0048-0048-

0048-

- 8400

- 830

0

- 8300

-8300

- 830

0

0038-

0038-

- 8

300

0038-

0038

-

- 8300

- 8200

- 820

0-8

200

- 820

0

0028

-

0028

-

0028-

- 8200

- 8100

- 810

0- 8

100

- 8100

0018-

- 80 00- 8

000

-800

0

-800

0

- 79

00

- 790

0-7

900

- 780

0

- 780

0- 7

800

- 770

0

- 770

0- 7

700

- 760

0

-760

0- 7

600

- 750

0

-750

0- 7

500

- 740

0

-740

0

0047

-

- 730

0

-730

0

0037

-

- 720

0

-72

00

0027

-

- 710

0

-71 0

0

- 700

0

- 7000

- 690

0

- 6900

-680

0

- 6 80

0

-67 0

0

- 6700

- 660

0- 6

500

-7,220

-8,089

-7,143

-8,067

-8,319

-8,321-8,364

-8,103

-7,230

-8,333-8,344

-8,347

-8,272

-8,498

-8,301

-8,194

-8,406

-8,319

-8,267

-7,509

-8,015

-7,744

-8,286

-7,775

-7,964 -8,231-7,744

-7,989-8,173

-8,088

-8,071

-8,073

-8,248

-8,195

-8,394

-8,398-8,360

-8,373

-8,386

-8,307

-8,335

-8,390

-8,305

-8,199-8,200

-8,183

-8,169-8,375

-8,289

-8,176

-8,205

-8,378

-8,229

-8,393

-8,230

-8,377

-8,246

-8,330

-8,368 -8,323-8,355

-8,203

-8,330

-8,325

-8,318

-8,289-8,373

-8,225

-8,365

-8,131

-8,330

-8,416

-8,544

-8,113

-8,002

-8,143

-7,202

-7,174

-7,304

-7,165

-7,167

-7,262-7,176

-7,813

-8,153

-8,454

-8,371-7,457

-8,285

-8,333-8,392

-7,982

-8,225-8,346

-8,105

-8,121

-7,938

-8,464

-8,052

-6500-6600-6700-6800-6900-7000-7100-7200-7300-7400-7500-7600-7700-7800-7900-8000-8100-8200-8300-8400-8500-8600-8700

U.B.6 Structure Map

FEET

0 5,280 10,560 15,840

POSTED WELL DATA

FMTOPS - U_B_6[SLP] (SS) (FEET)

CONTOURSFMTOPS - U_B_6 [SLP] - Top of Barnett Shale

FMTOPSU_B_6SLP.GRDContour Interval = 100

-870

0

-860

0

-840

0

-820

0

-800

0

-780

0

-760

0

-740

0

-720

0

-700

0

-680

0

-660

0


May 12, 2012

PETRA 5/12/2012 12:15:42 AM

Andrews

Ector

Martin

Midland

102°20'W

3°1

'32°0 0'N

32 °0 5'N2

5°1 0' N

102°25'W 102°15'W 102°10'W

32°0

0'N

32°0

5'N

3232° 1

0'N

N

32°1

5'N

102°25'W 102°20'W 102°15'W

53

Discussion

Strata comprising the lower Barnett were deposited in deep-water marine

conditions. The sidewall core sample taken from the lower Barnett interval, coupled with

the overall elevated gamma ray responses for the entire interval suggest hemipelagic

sedimentation exerted strong influence on the accumulation of strata. This is further

suggested by the dearth of terrigenous constituents present in the sample (Table 2). The

high TOC content is a by-product of anoxic conditions persisting throughout deposition,

which also resulted in the formation of pyrite. The thickest accumulations of the lower

Barnett coincide with the present-day location of the Central Basin Platform. High S1

and S2 values from the lower Barnett sample reveals that the interval contains sufficient

properties to have generated hydrocarbons.

The upper Barnett is composed of both calcareous/phosphatic shale and silty

limestones deposited in marine conditions. The presence of phosphate nodules and pyrite

framboids suggest an anoxic environment. The high density of pyrite and phosphate

could potentially affect any density measurements throughout the section.

A gross isopach of the entire upper Barnett section shows the thickest section in

the southeast. This pattern suggests that the main depocenter shifted slightly to the south

following the deposition of the lower Barnett. This shift may reflect early subsidence

related to the emergence of the Central Basin Platform (Fig. 23). The net isopach map,

taken to represent deposition of bioclastic debris, shows the thickest portion in the north,

decreasing in overall thickness to the south. This pattern is opposite to the gross isopach

pattern and suggests a northerly source for the flows. The likely source is the carbonate

54

platform that was present north of the study area during the Chesterian. If this is correct,

the carbonate constituents that comprise the debris flows were likely episodically sourced

from the platform to the basin via mass-gravity flows (Fig. 34).

Production History

Upper Mississippian fields in the Midland Basin are located in both platform and

basin environments. On the platform, trapping mechanisms are either structural or

stratigraphic, with limestone, dolomite, and/or chert providing the reservoir (Wright,

1979). South of the paleo-platform, fields including Moonlight, Lowe, Desperado, and

Bradford Ranch produce from the bioclastic-rich debris flows present in the upper

Barnett (Fig. 35). Not all fields are reported Mississippian, although that may be a

consequence of the aforementioned lack of age consensus. The trapping mechanism is

stratigraphic, which is a result of the detrital units thinning out on the flanks of the

sequence. A fracture network likely provides the means of production viability from the

“tight”, low porosity, low permeability reservoirs. Evidence for this includes a well’s

ability to drain an entire section and the abnormal pressure gradients (Unpublished Field

Reports). One example of the abnormal pressure gradient is a pressure test that was

applied to the Moonlight field. The test consisted of shutting in wells producing from

upper Mississippian units, while a new one was brought online. Wells 8,500 feet (2,590

meters) away recorded a pressure drop in an hour (Jim Henry, Petroleum Engineer,

personal communication, 2012). Well communication in that short time frame strongly

suggests the presence of a fracture network. Additionally, core recovered from the

Fasken 215-B in the Moonlight Field has a five-inch fracture from the U.B.2 bioclastic

55

Figure 34. A) Location of cross section D-D’ in relation to the study area (dashed red rectangle) and the Chesterian shelf. Modified from Hamilton and Asquith (2000). B) Idealized integration of the deposition of bioclastic mass-gravity flows in study area into Bay’s (1954) cross section. Modified from Bay (1954) and Ruppel and Kane (2006).

56

Figure 35. Map of oil fields that have produced hydrocarbons from the upper Barnett. Study area highlighted in yellow. Modified from Anonymous (1986).

57

carbonate section (Al Smith, Independent Geologist, personal communication, 2011).

Upper Mississippian detrital units were actively pursued in the mid seventies to late

eighties until an unfavorable economic climate curtailed activity.

Favorable economic prices have once again shifted focus to the liquids-rich

Midland Basin, with the “Wolfberry” (Permian) play dominating the industry’s focus.

Wolfberry trends overlap areas that were mapped containing thick portions of the upper

Barnett detritus strata. While it would increase well costs to drill deeper and test, the

potential for increased pay warrants exploration. All of the wells drilled in the original

fields were vertical. With the increased expertise of horizontal drilling, the ability to

increase contact to the “tight” reservoir coupled with fracture stimulation completion,

could aid in increasing permeability.

Conclusions and Recommendations

The top of the shale sequence underlying the “Atoka Lime” is presumptively

Chesterian in age, making it equivalent to the Barnett Shale Formation. Depths to the top

of the Barnett section range from ranges from 9,000 feet (2,750 meters) in the west along

the flank of the Central Basin Platform to 11,500 feet (3,500 meters) in the east. It can be

divided into an upper, calcareous unit and a lower, siliceous unit on the basis of

resistivity and GR responses. The upper unit can be further subdivided into six subunits

by log responses, to further aid in deciphering depositional trends. Isopach maps

constructed on the subunits containing carbonate detritus gravity flows suggest a northern

source, which coincides with the late Mississippian platform margin. Future work in

58

delineating the overall geometry and transport mechanics (point vs. line source) will be

crucial to further understand the deposition patterns.

Historically, established production comes from the upper subunits containing

increased porosity and permeability values. The encasing shales are likely to provide the

source. Although fracture detection was not completed in this study, it is likely to exert

significant control on the ability to exploit hydrocarbons. Preliminary analysis suggests

that weight percent TOC values can be estimated from the amount of separation from GR

and Rt curves. The lower Barnett had the highest TOC and gas shows, based on core and

petrophysical analysis.

Future study of the Barnett in the Midland Basin should incorporate

petrophysical, geophysical, geochemical, and core analysis. More age data should be

gathered from palynology and conodonts to better constrain the sequence. With the

benefit of being located in a mature province, old well logs and core reports are readily

available and should be used to further carry out correlations. Azimuthal angle versus

offset analysis and seismic coherency could provide the means to predict natural

fracturing in the sequence, aiding in delineating specific trends that warrant exploration

focus. While historic production has solely come from the upper subunits, the lower

Barnett with its appreciable TOC, S1 and S2 values could prove to be a viable horizontal

prospect.

59

References

Adams, D.C., and Keller, G.R., 1996, Precambrian basement geology of the Permian Basin region of West Texas and Eastern New Mexico: A geophysical perspective: American Association of Petroleum Geologists Bulletin, v.80, p. 410-431.

Adams, J.E., 1965, Stratigraphic-tectonic development of the Delaware Basin: American

Association of Petroleum Geologists Bulletin, v. 49, p. 2140-2148. Adams, J.E., Frenzel, H.N., Rhodes, M.L., and Johnson, D.P., 1951, Starved Pennsylvanian

Midland Basin: American Association of Petroleum Geologists Bulletin, v. 23, p. 1673-1681. Anonymous, 1986, Unraveling the mystery of the Atoka: Search, v. 2, p. 1-5. Ball, M., 1995, Permian Basin Province (044), in Gautier, D.L., Dolton, G.I. Takahashi, K.T., and

Varnes, K.L., eds., 1995 National assessment of United States oil and gas resources-Results, methodology, and supporting data: U.S. Geological Survey Digital Data Series DDS-30.

Bay, T. A., Jr., 1954, Mississippian system of Andrews and Gaines counties, Texas [Unpublished

MS thesis]: The University of Texas at Austin, 56 p. Bjorlykke, K., 2010, Source rocks and petroleum geochemistry, in Bjorlykke, K., ed., Petroleum

geoscience: From sedimentary environments to rock physics: Springer, Berlin, Germany, p. 339-349.

Broadhead, R.F., 2009, Mississippian strata of southeastern New Mexico: distribution, structure,

and hydrocarbon plays: New Mexico Geology, v.31, p. 65-71. Candelaria, M.P., 1990, “Atoka” detrital a subtle stratigraphic trap in the Midland Basin, in Flis,

J.E., and Price, R. C., eds., Permian Basin oil and gas fields; innovative ideas in exploration and development: West Texas Geological Society, v. 90-87, p.104-106.

Craig, L.C., and Connor, C.W., Coordinators, 1979, Paleotectonic Investigations of the

Mississippian System in the United States, U.S. Geological Survey Professional Paper 1010, Part III.

Frenzel, H.N., and 13 others, 1988, The Permian basin region, in Sloss, L.L., ed., Sedimentary

Cover-North American Craton; U.S.: Geological Society of America, The Geology of North America, Boulder, Colorado, v. D-2 p. 261-306.

Galley, J.E., 1958, Oil and geology in the Permian Basin of Texas and New Mexico, in Weeks,

L.G., ed., Habitat of oil: American Association of Petroleum Geologists, Tulsa, Oklahoma, p. 395-446.

Gutschick, R., and Sandberg, C., 1983, Mississippian Continental Margins on the Conterminous

United States, in Stanley, D.J. and Moore, G.T., eds., The Shelf break: Critical Interface on Continental Margins: Society of Economic Paleontologist Mineralogists, Tulsa, Oklahoma, Special Publication 33, p. 79-96.

60

Hamiliton, D.C., and Asquith, G.B., 2000, Depositional, digenetic, and production histories of Chester ooid grainstones in the Austin (Upper Mississippian) Field: Lea County, New Mexico, in DeMis, W., Nelis, M., and Trentham R.C., eds., The Permian Basin: Proving Ground for Tomorrows’s Technologies, West Texas Geological Society, Publication 00-109, p. 95-105.

Heslop, K.A., 2010, Generalized Method for the Estimation of TOC from GR and Rt, AAPG

Datapages/ Search and Discovery, #80117. Hills, J.M., 1984, Sedimentation, tectonism, and hydrocarbon generation in Delaware basin, West

Texas and southeastern New Mexico: American Association of Petroleum Geologists Bulletin, v. 68, p. 250-267.

IHS Energy, 2011, Permian Basin Production Data, accessed from PI Dwight, (July, 2011). King, P.B., 1948, Geology of the southern Guadalupe Mountains, Texas: U.S. Geological Survey

Professional Paper 251, 183 p. Kinley, T.J., Geology and hydrocarbon potential of the Barnett shale (Mississippian) in the

northern Delaware Basin, West Texas and Southeastern New Mexico [M.S. thesis]: Texas Christian University, Ft. Worth, 81 p.

Miall, A.D., 2008, The southern midcontinent, Permian Basin, Ouachitas, in Miall, A.D., ed., The

sedimentary basins of the United States and Canada: Elsevier B.V., Amsterdam, The Netherlands, p. 297-327.

Ruppel, S.C., and Kane, J., 2006, The Mississippian Barnett Formation: A source-rock, seal, and

reservoir produced by early Carboniferous flooding of the Texas craton: http://www.beg.utexas.edu/resprog/permianbasin/PBGSP_members/writ_synth/Mississippian_chapter.pdf (September, 2011).

Scholle, P., 2006, An introduction and virtual field trip to the Permian reef complex, Guadalupe

and Delaware Mountains, New Mexico-West Texas: http://geoinfo.nmt.edu/staff/scholle/guadalupe.html (October 2011).

Serra, O., ed., 1990, Element, Mineral, Rock Catalog, Schlumberger.

Wright, W.F., 1979, Petroleum geology of the Permian Basin: West Texas Geological Society,

Midland, TX, 98 p. Wright, W., 2006, Depositional history of the Atokan Succession (Lower Pennsylvanian) in the

Permian Basin: http://www.beg.utexas.edu/resprog/permianbasin/PBGSP_members/writ_synth/Atoka.pdf (August, 2011).

Ye, H., Royden, L., Burchfiel, C., and Schuepbach, M., 1996, Late Paleozoic deformation of

interior North America; the greater ancestral Rocky Mountains: American Association of Petroleum Geologists Bulletin, v. 80, p. 1397-1432.

61

Appendix I. Geochemical Report From the Fasken Fee BM #1 SWD

Figure I 1. Geochemical logs for BM SWD #1 well

Figure I 2. Kerogen quality relative to TOC Vs. hydrocarbon potential for the BM SWD well

Client: GeoSystemsField / Well: File # G2142Contact: Chuck Segrest

GeoMark ID#: RGES-110602Source Rock Analyses

GeoMark Source Rock Services218 Higgins StreetHumble, TX 77338 1

(832) [email protected]

June 20, 2011

GeoSystems - Chuck Segrest G2142,

Norm. Oil Content, S1/TOC Production Index, S1/(S1+S2) Maturity Indicators

11,400

11,500

11,600

11,700

11,800

11,900

12,000

12,1000.00 0.25 0.50 0.75 1.00

Me

as

ure

d D

ep

th,

MD

(ft

)

Production Index, S1/(S1+S2)

Gas Generation

Imm

atur

e

Oil Gen.

415 435 455 475 495 515 53511,400

11,500

11,600

11,700

11,800

11,900

12,000

12,1000.2 0.8 1.4 2.0 2.6 3.2

Me

as

ure

d D

ep

th,

MD

(ft

)

Vitrinite Reflectance (or VR Equivalent)

Measured %Ro

PyGCMS - Z Maturity

Tmax

Gas Generation

Imm

atur

e Oil Generation

Tmax (°C)

SOURCE ROCK ANALYSES

GEOMARK GEOMARK RESEARCH, LTD.

0 20 40 60 80 10011,400

11,500

11,600

11,700

11,800

11,900

12,000

12,1000 50 100 150 200

Measu

red

Dep

th, M

D (

ft)

Normalized Oil Content, S1/TOC

S1/TOC

% Carbonate

% Carbonate

Low

Mat

urity

or

Exp

elle

d

Early

Mat

ure

Sour

ce R

ock

Mature / Stained Source Rock

Oil / Gas Production or Contamination





June 20, 2011


Kerogen Quality Plot

0

10

20

30

40

50

60

0 2 4 6 8 10 12 14 16

Rem

aini

ng H

ydro

carb

on P

oten

tial,

S2 (m

g H

C /

g R

ock)

Total Organic Carbon, TOC (wt %)

Type I: Oil ProneUsually Lacustrine

Type III: Gas Prone

Mixed Type II / III:Oil / Gas Prone

Type II: Oil ProneUsually Marine

Dry Gas Prone

HI = 50

HI = 200

HI = 350

HI = 700

SOURCE ROCK ANALYSESGEOMARK GEOMARK RESEARCH, LTD.

62

Figure I 3. Kerogen type and maturity based on hydrogen index and Tmax.





June 20, 2011


Kerogen Type and Maturity

0

200

400

600

800

1000

400 410 420 430 440 450 460 470 480 490 500

Hyd

roge

n In

dex

(mg

HC

/ g

TOC

)

Tmax (°C)

TYPE I KEROGEN

TYPE II KEROGEN

TYPE III KEROGEN

SOURCE ROCK ANALYSESGEOMARK GEOMARK RESEARCH, LTD.

~ 0.6 % Ro ~ 1.4 % Ro

Immature Oil Generation Gas Generation

63





June 20, 2011


Kerogen Quality Plot

SOURCE ROCK ANALYSES

GEOMARK GEOMARK RESEARCH, LTD.

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

380 400 420 440 460 480 500 520 540 560 580 600

Ke

ro

ge

n C

on

ve

rs

ion

, P

I (S

1/(

S1

+S

2)

Tmax (C)

Immature Dry Gas ZoneOil Zone CondensateWet Gas

Zone

Stained or Contaminated

Low Level Conversion

Figure I 4. Kerogen quality plot for the BM SWD #1 well

64

Appendix II. Palynological Reports

Ger

ald

Waa

nder

s, C

onsu

lting

Pal

ynol

ogis

t14

75 R

anch

o E

ncin

itas

Driv

e, E

ncin

itas,

Cal

iforn

ia 9

2024

-703

1P

hone

: (8

58) 7

59-0

180,

Em

ail:

waa

npal

y@ro

adru

nner

.com

Figu

re 1

Age

Dep

th

Convolutispora sp.

Cordaitina sp.

Calamospora breviradiata

Nuskoisporites crenulatus

Punctatisporites spp.

Thymospora sp.

Tsugaepollenites jonkeri

Verrucosisporites pergranulus

Acanthotriletes spp.

Aculeisporites varibilis

Punctatosporiotes rotoundus

Wilsonites sp.

Direticuloidospora sp.

Disaccites spp.

Striatites limpidus

Limitisporites monstruosus

Potoniesporites bharadwaji

Potoniesporites novicus

Sphaeripollenites elphinstonei

Apiculatisporis spp.

Florinites spp.

Cordaitina bractea

Hamiapollenites saccatus

Cirratriradites ornatus

Latensina trileta

Florinites visendus

Leiotriletes spP.

Ibrahimisporites brevispinosus

Endosporites formosus

Laevigatosporites vulgaris

Laevigatosporites minimus

Llundbladispora gigantea

Angulisporites splendidus

Crassispora kosankei

Cyclogranisporites pergranulus

Laevigatosorites maximus

Lycospora pusilla

Raistrickia macra

Vestispora profunda

Densosporites annulatus

Granulatisporites microgranifer

Lophotriletes pseudoaculeatus

Microrticulatisporites nobilis

Verrucosisporites verrucosus

Vestispora laevigata

Dictyotriletes bireticulatus

Cristatisporites solaris

Cirratriradites saturni

Densosporites tenuis

Endosporites globiformis

Endosporites ornatus

Lycospora pseudoannulatus

Reticulatisporites reticulatus

Camptotriletes superbus

Lophotriletes microsaetosus

Punctatisporites sinuatus

Schopfites dimorphus

Cirratriradites rarus

Discernisporites micromanifestus

Kraeuselisporites ornatus

Waltzispora planiangulata

Calamospora pallida

Pilosisporites venustus

Spelaeotriletes aranaceus

Ahrensisporites duplicatus

Crassispora maculosa

Raistrickia saetosa

Remysporites magnificus

Schopfites claviger

Raistrickia nigra

Aurororaspora solisortus

Densosporites spitzbergensis

Verrucosisporites nodosus

Convolutispora mellita

Auroraspoora macra

Grandispora echinata

Murospora dupla

Verrucosisporites papulosus

Anaplanisporites sp.

Diatomozonotriletes saetosus

Cyclogranisporites paleophytus

Rotaspora fracta

Knoxisporites cinctus

Microreticulatsporites hortonensis

Tripartites vetustus

Vellatisporites ciliaris

Schulzospora rara

Raistrickia clavata

Knoxisporites literatus

Knoxisporites stephanophorus

Spelaeotriletes pretiosus

Anaplanisporites baccatus

Auroraspora hyalina

Hymenozonotriletes parvimammatus

Hymenozonotriletes pusillites

Tasmanites sp.

Scolecodont sp.

9700

-975

097

50-9

800

RQ

9800

-985

0R

Q98

50-9

900

RR

R99

00-9

950

RR

RR

9950

-10,

000

RQ

10,0

00-1

0,05

0R

RR

RR

R10

,050

-10,

100

RR

RR

10,1

00-1

0,15

0R

RR

R10

,150

-10,

200

RR

RR

RR

10,2

00-1

0,25

0R

RR

RR

RR

R10

,250

-10,

300

RR

RR

RR

R10

,300

-10,

350

RR

RR

RR

RR

10,3

50-1

0,40

0R

RR

10,4

00-1

0,45

0F

RR

R10

,450

-10,

500

RR

RR

RR

10,5

00-1

0,55

0R

R10

,550

-10,

600

RR

RF

RR

10,6

00-1

0,65

0R

RR

RR

10,6

50-1

0,70

0R

RR

R10

,700

-10,

750

RR

RR

RR

10,7

50-1

0,80

0R

RR

10,8

00-1

0,85

0R

R10

-850

,10,

900

RR

RR

R10

,900

-10,

950

RR

RR

RR

R10

,950

-11,

000

RR

RR

RR

RR

RR

RR

11,0

00-1

1,05

0F

RR

FF

RR

RR

RR

RR

RQ

11,0

50-1

1,10

0R

RR

RR

RR

FR

RR

R11

,100

-11,

150

RF

RF

RR

RR

CR

RR

RR

11,1

50-1

1,20

0R

RR

FR

RR

AR

RR

RR

RR

RR

RR

11,2

00-1

1,25

0R

RR

RR

RA

RR

RR

RQ

RR

R11

,250

-11,

300

RR

CR

RR

RR

R11

,300

-11,

350

CR

RR

AR

RR

RR

RR

RR

11,3

50-1

1,40

0R

RR

AA

RR

RF

RR

RR

RR

R11

,400

-11,

450

RR

RA

AR

RR

AR

RR

RR

RR

11,4

50-1

1,50

0A

AQ

RR

RF

RR

RR

R11

,500

-11,

550

RR

RA

AR

RR

RR

RR

R11

,550

-11,

600

RA

AR

RR

RR

RR

R11

,600

-11,

650

RF

AA

AR

RR

11,6

50-1

1,70

0R

RA

AR

RF

RR

RR

RR

R1,

700-

11,7

50F

RA

AR

FR

RR

RR

RR

11,7

50-1

1,80

0R

RA

AR

RF

RR

RR

R11

,800

-11,

850

RR

RA

AR

RR

RR

RR

RR

11,8

50-1

1,90

0R

RR

AA

RF

RR

FR

R11

,900

-11,

950

CR

RA

AR

FR

RF

RR

R11

,950

-12,

000

RR

AA

RR

RR

RR

12,0

00-1

2,05

0R

RA

AR

RR

RR

QR

12,0

50,-1

2,10

0R

RA

RR

RC

RR

RR

12,1

00-1

2,15

0F

RA

FR

RR

RR

RR

R12

,150

-12,

200

FF

RR

FR

RR

R12

,200

-12,

250

RR

RR

CF

RR

FR

QR

RR

RR

12,2

50-1

2,30

0A

FA

RR

QR

RR

QR

RR

RR

12,3

00-1

2,35

0R

RA

RR

RR

RR

RR

12,3

50-1

2,40

0R

RR

RR

RR

R12

,400

-12,

450

RR

AA

RR

RR

RFa

men

nian

12,4

50-1

2,50

0F

RR

AA

RQ

RR

RR

RR

RR

R

Fask

en O

il &

Ran

chR

= R

are,

less

than

6 s

peci

men

s/sl

ide

Fee

BM

#1

SW

DF

= Fr

eque

nt, 6

-15

spec

imen

s/sl

ide

Sec

. 15,

Blk

. 40,

T-1

-N, T

& P

RR

Com

pany

Sur

vey

C =

Com

mon

, 16-

30 s

peci

men

s/sl

ide

And

rew

s, C

o. T

exas

A =

Abu

ndan

t, ov

er 3

0 sp

ecim

ens/

slid

eQ

= Q

uest

iona

ble

Iden

tifac

tion

Dar

k O

rang

e =

Pro

babl

e U

p-ho

le C

onta

min

atio

n

Spo

res

Mic

r.3/

22/1

1

Leon

ardi

an o

r Old

er

Wol

fcam

pian

Kin

derh

ooki

an?

Mis

sour

ian

to

Des

moi

nsia

n (U

ndiff

eren

tiate

d)

Ato

kan

Che

ster

ian

Mer

amec

ian

Osa

gean

?

Figure II. 1. Specimen report for the Fasken Fee BM #1 SWD well

65

Ger

ald

Waa

nder

s, C

onsu

lting

Pal

ynol

ogis

t14

75 R

anch

o E

ncin

itas

Driv

e, E

ncin

itas,

Cal

iforn

ia 9

2024

-703

1P

hone

: (8

58) 7

59-0

180,

FA

X:

(858

) 759

-902

8, E

mai

l: w

aanp

aly@

road

runn

er.c

om

Figu

re 1

Age

Dep

th

Cordaitina sp.

Disaccites sp.

Potoniesporites bharadwaji

Potoniesporites novicus

Schopfipollenites sp.


Wilsonites sp.

Calamospora breviradiata

Leiotriletes sp.

Angulisporites sp.

Limitissporites monstruosus

Florinites spp.

Dictyotriletes bireticulatus

Endosporites globiformis

Lycospora pusilla



Laevigatosporites vulgaris



Angulisporites splendidus

Punctatosporites rotundus


Lycospora pseudoannulatus

Vestigisporites sp.

Apiculatisporis aculeatus


Lundbladispora gigantea

Savitrisporites camptotus


Lopohotriletes microsaetosus

Schulzospora rara


Convolutispora sp.


Leiotriletes politus

Cirratriradites rarus

Laevigatosporites maximus

Raistrickia microhorrida




Waltzispora polita

Apiculatisporis sp.

Raistrickia nigra

Savitrisporites nux

Schopfites claviger

Cristatisporites bellus

Grandispora spinosa

Convolutispora flexuosa

Latosporites sp.

Raistrickia clavata

Spelaeotriletes pretiosus

Verruretusispora magnifica

Leiosphaera spp.

Tasmanites spp.

Algal Cuticle

Micrhystridium echinosum

9900

-998

0R

RR

RR

9980

-10,

060

RR

RR

10,0

60-1

0,14

0R

RR

R10

,140

-10,

200

RR

RR

10,2

00-1

0,28

0R

R10

,280

-10,

360

RR

R10

,360

-10,

420

RR

R10

,420

-10,

480

RR

10,4

80-1

0,56

0R

RR

10,5

60-1

0,64

0R

FR

10,6

40-1

0,70

0F

RR

RR

RF

10,7

00-1

0,78

0F

FR

RF

RR

RR

R10

,780

-10,

840

RR

RR

RF

RR

10,8

40-1

0,86

0F

RR

AR

RR

RQ

R10

,860

-10,

940

RR

AR

RR

RR

RR

R10

,940

-11,

000

RR

RR

AR

RR

RR

11,0

00-1

1,08

0R

AR

RA

R11

,080

-11,

160

RR

AR

AR

RR

R11

,160

-11,

220

RA

RR

FR

RR

RR

11,2

20-1

1,28

0F

AF

AR

RR

R11

,280

-11,

340

RA

FR

AR

RR

RR

RR

R11

,340

-11,

420

FA

RA

RR

RR

RR

RR

R11

,420

-11,

500

FA

RA

RR

RR

RR

R11

,500

-11,

580

RA

RA

RF

FR

FR

R11

,580

-11,

660

RA

RR

11,6

60-1

1,74

0R

R11

,740

-11,

820

RR

RR

R11

,820

-11,

900

RA

RR

RR

RR

RC

11,9

00-1

1,98

0A

RR

RR

C11

,980

-12,

050

RC

RR

12,0

50-1

2,11

0R

AR

RR

RC

A12

-110

-12,

160

RA

RR

RQ

12,1

60-1

2,20

0R

AR

CR

RR

RR

Fask

enR

= R

are,

less

than

6 s

peci

men

s/sl

ide

"BL"

No.

1 S

WD

F

= Fr

eque

nt, 6

-15

spec

imen

s/sl

ide

C =

Com

mon

, 16-

30 s

peci

men

s/sl

ide

A =

Abu

ndan

t, ov

er 3

0 sp

ecim

ens/

slid

eQ

= Q

uest

iona

ble

Iden

tifac

tion

Dar

k O

rang

e =

Pro

babl

e U

p-ho

le C

onta

min

atio

n

4/12

/12

Mic

ropl

ank.

Inde

term

inat

e

Spo

res

Che

ster

ian

Kin

derh

ooki

an?

Mer

amec

ian

to

Osa

gean

(U

ndiff

eren

tiate

d)

Ato

kan

Wol

fcam

pian

to

Des

moi

nsia

n (U

ndiff

eren

tiate

d)

Figure II. 2. Specimen report for the Fasken Fee BL #1 well.

66

Ger

ald

Waa

nder

s, C

onsu

lting

Pal

ynol

ogis

t14

75 R

anch

o E

ncin

itas

Driv

e, E

ncin

itas,

Cal

iforn

ia 9

2024

-703

1P

hone

: (8

58) 7

59-0

180,

FA

X:

(858

) 759

-902

8, E

mai

l: w

aanp

aly@

road

runn

er.c

om

Figu

re 1

Age

Dep

th

Caiospora magna

Calamospora spp.


Densosporites sphaerotriangularis

Densosporites spp.

Disaccites spp.

Florinites spp.

Laevigatosporites maximus

Lophotriletes microsaetosus


Lycospora pusilla

Potoniesporites spp.


Florinites eremus

Savitrisporites camptotus

Schopfipollenites sp.

Verrucosisporites spp.

Angulisporites spendidus


Cyclogranisporites orbicularis

Endosporites spp.

Raistrickia aculeata

Reticulatisporites polygonalis

Apiculatisporis sp.

Converrucosisporites sp.

Florinites junior

Florinites ovalis



Florinites pellucidus

Leiotriletes adnatus

Calamospora pallida

Cyclogranisporites pergranulatus

Laevigatosporites sp.

Lycospora pseudoannulata

Raistrickia fulva

Vestispora irregularis

Reticulatisporites reticulatus

Vestispora cancellata

Cirratriradites saturni


Granulatisporites granulatus


Cristatisporites solaris

Raistrickia saetosa

Gravisporites sphaerus


Bellispores nitidus

Crassispora maculosa



Reinchospora triangularis


Mooreisporites trigallerus

Schulzospora rara

Verrucosisporites baccatus

Grandispora echinata

Knoxisporites stephanophorus

Knoxisporites cinctus

Convolutispora mellita


Tricidarisporites magnificus

Knoxisporites triradiatus

Rugospora polyptycha

Schopfites claviger

Cyclogranisporites paleiphytus

Convolutispora spp.

Camptotriletes superbus

Anaplanisporites baccatus

Secarisporites sp.

Verrucosisporites nitidus

Crassispra sp. (Eames)

Geminospora sp.

Hymenozonotriletes lepidophytus

Raistrickia clavata

Spelaeotriletes balteatus

Vellatisporites pusillites

Auroraspora macra

Cyclogranisporites sp.

Lophozonotriletes sp.

Hymenozonotriletes explanatus

Verruretusispora magnifica

Densosporites variomarginatus

Dictyotriletes cancellatus

Microreticulatisporites sp.

Aurospora solisorta

Tasmanites spp.

Scolecodont sp.

Desmochitina sp. ?

Chitinozoan Fragments

Michrhystridium echinosum

Navifusa sp.

Chitinozoan sp.

Mis

sour

ian

10,6

50-1

0,70

0R

RR

RR

FR

RR

RF

FC

R10

,700

-10,

750

RR

RR

FR

FR

RR

R10

,750

-10,

800

RR

R10

,800

-10,

850

RR

RR

CR

RR

RR

RR

R10

,850

-10,

900

RR

RR

RR

RR

RR

RR

R10

,900

-10,

950

RR

RF

RC

FR

FR

RF

RR

10,9

50-1

1,00

0R

FC

FR

RF

RR

RR

RR

11,0

00-1

1,05

0R

RR

AR

RR

RR

RR

11,0

50-1

1,10

0F

AF

RR

RR

RR

RR

RR

RR

11,1

00-1

1,15

0R

RF

RA

FR

RR

RR

RR

11,1

50-1

1,20

0C

CC

RA

RR

RR

RR

RR

RR

R11

,200

-11,

250

AA

RA

FR

RA

RR

RR

AR

RR

11,2

50-1

1,30

0A

FR

AR

RA

RR

RA

RR

11,3

00-1

1,35

0A

RA

RR

AR

RA

RR

RR

R11

,350

-11,

400

AR

AR

RR

AR

RR

RA

RR

RR

11,4

00-1

1,45

0A

AA

FR

RA

RR

RA

RR

RR

11,4

50-1

1,50

0R

RR

AA

RR

RR

RR

RR

RR

11,5

00-1

1,55

0R

RA

RR

RR

RR

RR

11,5

50-1

1,60

0R

FA

RR

RR

AR

R11

,600

-11,

650

FR

RA

RR

RR

R11

,650

-11,

700

CR

AR

RC

RR

11,7

00-1

1,75

0R

FA

RR

RR

FR

11,7

50-1

1,80

0R

RF

RR

RR

11,8

00-1

1,85

0R

RF

FR

RR

R11

,850

-11,

900

RF

RR

RF

RR

11,9

00-1

1,95

0R

FA

FR

FR

R11

,950

-12,

000

RF

AR

RR

RF

RR

12,0

00-1

2,05

0R

RA

FR

RR

AIn

dete

rmin

ate

12,0

50-1

2,10

0R

RF

FR

RF

RK

inde

rhoo

k. to

Fam

enni

an12

,100

-12-

150

RR

FR

FR

RR

R12

,150

-12,

200

RR

RR

RR

RR

RR

RR

RR

RR

AR

12,9

40-1

2,94

5A

AR

RR

RR

RR

RR

13,0

50-1

3,10

0R

AR

RR

RA

RR

RR

RR

13,1

00-1

3,15

0F

AR

RR

RA

RR

RR

RF

RR

13,1

50-1

3,20

0R

AR

AR

RR

RA

R13

,200

-13,

250

RA

FR

AR

RR

RR

AR

13,2

50-1

3,30

0A

RR

AR

RR

R13

,300

-13,

350

RA

RA

R13

,350

-13,

400

RA

RC

RR

R

Dav

id F

aske

nR

= R

are,

less

than

6 s

peci

men

s/sl

ide

"BS

" No.

1 S

WD

Re-

entry

F =

Freq

uent

, 6-1

5 sp

ecim

ens/

slid

eS

ec. 4

1, B

lk. 4

0 T-

1-N

T&

P R

R C

o. S

urve

y C

= C

omm

on, 1

6-30

spe

cim

ens/

slid

eM

idla

nd, C

o. T

exas

A =

Abu

ndan

t, ov

er 3

0 sp

ecim

ens/

slid

eQ

= Q

uest

iona

ble

Iden

tifac

tion

Dar

k O

rang

e =

Pro

babl

e U

p-ho

le C

onta

min

atio

n

Silu

rian

to O

rdov

icia

n U

ndiff

eren

tiate

d

Spo

res

Mic

ropl

ankt

on11

/9/1

0

Che

ster

ian

Ato

kan

Mer

amec

ian

to

Osa

gean

(U

ndiff

eren

tiate

d)

Des

moi

nsia

n

Figure II. 3. Specimen report for the Amoco David Fasken BS #1 well.

Vita

Personal Clark Harrison Osterlund Background Fort Worth, Texas Born May 18, 1988, Midland, TX Son of David and Eve Osterlund Education Bachelors of Science in Geology, 2010 Baylor University, Waco, TX Master of Science in Geology, 2012 Texas Christian University, Fort Worth, TX Experience Intern Geologist, summers 2007-2011 Fasken Oil and Ranch Ltd. Midland, TX Intern Geologist, 2011-2012 BOPCO Ltd., Fort Worth TX Professional American Association of Petroleum Geologists (AAPG) Memberships West Texas Geological Society (WTGS)

ABSTRACT

THE BARNETT SHALE (MISSISSIPPIAN) IN THE CENTRAL MIDLAND BASIN, (ANDREWS, ECTOR, MARTIN, AND MIDLAND COUNTIES)

By Clark H. Osterlund, M.S., 2012 Department of Geology, Energy, and the Environment

Texas Christian University

Dr. Helge Alsleben – Professor of Geology Dr. R. Nowell Donovan – Professor of Geology, and Provost

Stonnie Pollock – Geologist, Fasken Oil and Ranch Ltd.

Fine-grained units underlying the Atoka Lime Formation in the Midland Basin have

historically been interpreted as Pennsylvanian (Atokan) or Mississippian (Chesterian) strata.

Recent palynology data suggest that the shale was deposited during the late Mississippian

(Osagean-Chesterian), making it equivalent to the Barnett Shale. The trend of the Barnett was

studied in a 25-mi2 (~65 Km2) area in the Central Midland Basin.

In the study area, siliceous-calcareous units comprising the Barnett shale can be divided

into an upper and lower unit. The upper unit can be further subdivided into six subunits by log

curve markers, interpreted as gravity-flow deposits consisting of silty bioclastic debris. Isopach

maps of the flow deposits suggest a source to the north. Preliminary TOC analyses suggest that

the upper Barnett section is relatively TOC lean, whereas the lower Barnett has higher values.

Exploration focus can be enhanced by detailed mapping of flows for the upper Barnett.

the barnett shale (mississippian) in the central …

Documents