1. BERG - HUGHES
C E N T E R
Geologic Analysis of
the East Texas Basin in
Navarro County
Telemachos Manos

2. BERG - HUGHES
C E N T E R
• Objective
• Understand the geologic trends of Upper and Lower Cretaceous
units on the west flank of the East Texas Basin, Navarro County
• Correlated 36 SP well logs across Navarro County
• Even spatial distribution across fault lines and production zones.
• Identified key areas where data is lacking
• Generated a Structure Map of the Base of Austin Chalk
• Structure- Dips from NW-SE (structural high in NW)
• Impacted by San Marcos Arch and Mexia Fault Zone
• Stratigraphic Thickness Analysis
• Austin Chalk- Thickens to the Northeast
• Eagle Ford Formation- Thickens to the North and West
• Upper section locally missing due to normal faulting
• Woodbine Formation-thickens to the East
• Buda Formation-thickens to the East
• Del Rio Formation- thickens to the Northeast
• Play Analysis
• Production is greatest in areas where the thick bottom sand of the
Woodbine is directly adjacent to normal fault surfaces on the
upthrown-footwall side.

3. BERG - HUGHES
C E N T E R
Navarro County
East Texas Basin
• Jurassic Rifting of the Gulf of
Mexico
• Topographically Influenced
by Sabine Uplift and passive
margin.
• Louann Salt Deposits
influence updip detachments
San Marcos Arch
• Mid- rift high
• Jurassic in age
• Western extent of East
Texas Basin
Section of Study
• Mid-Late Cretaceous Rocks
• Del Rio through Taylor
Formation
(Donovan et al., 2015)

4. BERG - HUGHES
C E N T E R
Mexia–Talco Fault Zone
• Updip detachment surface of gravity
sliding due to the underlying Louann Salts
• Fault trend traces the extent of the salt
body
• Graben structures are conducive to lateral
migration of fluids  transport pathway.
• Monoclines on up-thrown surface
(Ambrose et al., 2009)
W E

5. BERG - HUGHES
C E N T E R
Gather Data
Determine Formation Boundaries and
Surfaces
Generate County Base Map (36 well logs)
Transport Picked Surfaces onto Base Maps
Generate Isopachs and Structure Maps
Import Fault Surfaces from Publications
Modify Structure Maps to Adhere to Faults

6. BERG - HUGHES
C E N T E R
AlbianConiacianTuronianCenomanian
42_349_31917
SP (MV) Res (Ohm)
Austin
150’-480’
Eagle Ford
150’-480’
K80sb
K72sb
K65sb
K63sb
Upper
150’-450’
Lower
35’-105’
K56sb
K58sb
K60sb
Woodbine
290’-720’
Buda
40’-180’
Del Rio
60’-120’
K65mfs
K60mfs
K61mfs
K62mfs
K56mfs
Austin Chalk
• High resistivity fossiliferous
limestone/chalk
Eagle Ford Shale
• Carbonate mudrock
• Subdivided into upper and lower
member
• Lower member higher TOC, gamma,
resistivity
Woodbine Formation
• Interbedded shale and sand
• Sand has strong reservoir potential
• Morrow Payzone – primary producing
reservoir
Buda Limestone
• Interbedded limestone, marl, and
calcareous shale
Del Rio Shale
• Calcareous silt and clay-rich shale
Georgetown
• Fossiliferous micrite, marl, and mud
Type Well
Mexia Fault Zone
Georgetown
Morrow
Payzone
35’-80’

7. BERG - HUGHES
C E N T E R
NW Shelf - Navarro County
• Units shallow and thin to the NW.
• Outside the fault zone, economically targeted reservoirs are
above the Taylor
• Wells do not penetrate the Austin Chalk or Woodbine
0 2 4 6 81
Miles
Mexia Fault Zone

8. BERG - HUGHES
C E N T E R
0 1 2 3 40.5
Miles
Southern Navarro County
• Units shallow and thin to the W.
• Outside the extent of the fault surface, Woodbine production
is minimal
• Few wells penetrate the Woodbine
Mexia Fault Zone

9. BERG - HUGHES
C E N T E R
0 1 2 3 40.5
Miles
Mexia Fault Zone – Navarro County
• Majority of production focused on fault footwall surfaces
• Vertical displacement of units, Woodbine reservoir adjacent
to Eagle Ford source rock
• Lateral migration of fluids
Mexia Fault Zone
Corsicana Field

10. BERG - HUGHES
C E N T E R
Depth to Base of
Austin (ft.)

11. BERG - HUGHES
C E N T E R
345543154933931341353411133784
A A’
A
A’
K60mfs
K61mfs
K62mfs
Austin
UEF
LEF
Buda
Del Rio
Georgetown
Woodbine
SW NE
K6
K61
K60
Mexia Fault Zone

12. BERG - HUGHES
C E N T E R
345543154933931341353411133784
A A’
A
A’
K60mfs
K61mfs
K62mfs
Austin
UEF
LEF
Buda
Del Rio
Georgetown
Woodbine
SW NE
UEF
LEF
Woodbine
Mexia Fault Zone

13. BERG - HUGHES
C E N T E R
345793160734480339313186231430 34987
B B’
Austin
UEF
LEF
Buda
Del Rio
Georgetown
WoodbineK60mfs
K61mfs
K62mfs
B
B’
NW SE
Mexia Fault Zone

14. BERG - HUGHES
C E N T E R
345793160734480339313186231430 34987
B B’
Austin
UEF
LEF
Buda
Del Rio
Georgetown
WoodbineK60mfs
K61mfs
K62mfs
B
B’
NW SE
Mexia Fault Zone

15. BERG - HUGHES
C E N T E R
Thickness (ft)

16. BERG - HUGHES
C E N T E R
Thickness (ft)

17. BERG - HUGHES
C E N T E R
Thickness (ft)

18. BERG - HUGHES
C E N T E R
Thickness (ft)

19. BERG - HUGHES
C E N T E R
42_349_31917
SP (MV) Res (Ohm)
Austin
150’-480’
Eagle Ford
150’-480’
K80sb
K72sb
K65sb
K63sb
Upper
150’-450’
Lower
35’-105’
K56sb
K58sb
K60sb
Woodbine
290’-720’
Buda
40’-180’
Del Rio
60’-120’
K65mfs
K60mfs
K61mfs
K62mfs
K56mfs
Georgetown
Morrow
Payzone
35’-80’
(Hill & Guthrie, 1943)
Thickness (ft)

20. BERG - HUGHES
C E N T E R
Shale
More Sand
towards the W
Sand

21. BERG - HUGHES
C E N T E R
Thickness (ft)

22. BERG - HUGHES
C E N T E R
Thickness (ft)

23. BERG - HUGHES
C E N T E R
• Production is greatest where thick Woodbine sand reservoirs are
adjacent to fault surfaces on the upthrown footwall.
(Modified from Hill & Guthrie, 1943)
Woodbine
Morrow Payzone
‘Old’ Corsicana Field
LEF
UEF
No
Production

High TOC LEF directly
adjacent to lower
Woodbine Reservoir
Drilled pre-1920s

24. BERG - HUGHES
C E N T E R
Depth to
Base of
Austin (ft)
Thickness of
Morrow (ft)
Stoeser et al., (2005)

25. BERG - HUGHES
C E N T E R
• Objective
• Understand the geologic trends of Upper and Lower Cretaceous
units on the west flank of the East Texas Basin, Navarro County
• Correlated 36 SP well logs across Navarro County
• Even spatial distribution across fault lines and production zones.
• Identified key areas where data is lacking
• Generated a Structure Map of the Base of Austin Chalk
• Structure- Dips from NW-SE (structural high in NW)
• Impacted by San Marcos Arch and Mexia Fault Zone
• Stratigraphic Thickness Analysis
• Austin Chalk- Thickens to the Northeast
• Eagle Ford Formation- Thickens to the North
• Upper section locally missing due to normal faulting
• Woodbine Formation-thickens to the East
• Buda Formation-thickens to the East
• Del Rio Formation- thickens to the Northeast
• Play Analysis
• Production is greatest in areas where the thick bottom sand of the
Woodbine is directly adjacent to normal fault surfaces on the
upthrown-footwall side.

26. BERG - HUGHES
C E N T E R
• Ambrose, W. A., Hentz, T. F., Bonnaffe, F., Loucks, R. G., Brown Jr, L. F., Wang, F. P.,
& Potter, E. C. (2009). Sequence-stratigraphic controls on complex reservoir
architecture of highstand fluvial-dominated deltaic and lowstand valley-fill deposits in
the Upper Cretaceous (Cenomanian) Woodbine Group, East Texas field: Regional
and local perspectives. AAPG bulletin, 93(2), 231-269.
• Donovan, A. & Gardner, R. (2015) "Chronostratigraphic Relationships of the
Woodbine and Eagle Ford Groups Across Texas." Gulf Coast Association of
Geological Societies Journal, v. 4, p. 67–87.
• Hill, H. B. & Guthrie, R. K. (1943) “Analysis of Oil Production in the Near-Depleted
Mexia-Powell Fault Fields of Texas”. U.S. Department of the Interior Bureau of Mines
Report of Investigations. R. I. 3712. August 1943
• Stoeser, Douglas B., Green, Gregory N., Morath, Laurie C., Heran, William D.,
Wilson, Anna B., Moore, David W., and Bradley S. Van Gosen (2005). “Preliminary
Integrated Geologic Map Databases for the United States Central States: Montana,
Wyoming, Colorado, New Mexico, Kansas, Oklahoma, Texas, Missouri, Arkansas,
and Louisiana”. The State of Texas: U.S. Geological Survey Open-File Report 2005-
1351, U.S. Geological Survey, Denver, CO.
Special Thanks to:
• Melissa Meyer
• Clyde Findlay
• Charlie Niles
• Eric Peavey