PSCharacterization of the Woodford Shale in Outcrop and Subsurface in Pontotoc and Coal Counties, Oklahoma*
Ryan Miller1 and Roger Young2
Search and Discovery Article #50052 (2007)
Posted September 5, 2007
*Adapted from poster presentation at AAPG Annual Convention, Long Beach, California, April 1-4, 2007.
1Devon Energy Corporation, Oklahoma City, OK ( firstname.lastname@example.org )
2University of Oklahoma, Norman, OK
In the Arkoma basin the Woodford shale has been exploited as an unconventional resource due to advancements in the geological and engineering fields in the past three years. Gas production from the Woodford shale is facilitated by natural and hydraulic fracturing of the formation. The focus of this study is the characterization of the Woodford to better understand the natural fracturing. Data in the form 2D and 3D seismic data sets, well logs and a Woodford shale outcrop were utilized.
The Woodford shale was interpreted on available well data. The resulting tops were correlated to the 2D and 3D seismic data sets to provide a regional stratigraphic and structural interpretation of the Woodford in the study area.
The principal stress components were characterized from the world stress map and FMI data. Well logs in the 3D seismic survey served as the primary source of local paleostress and in situ stress orientations. The orientation of the faults and joints in the study area were correlated based on strike and dip. The result is a change in the strike orientation and degree of dip over the twenty-six miles separating the outcrop and the 3D seismic survey. The resulting characterization of the Woodford shale will facilitate gas production by exploiting natural fractures.
Stress fields in the Woodford Shale can be correlated in outcrop and subsurface. The relationship between fractures in outcrop and faults in the subsurface and their related stresses can provide guidance in lateral orientation and efficient recovery efforts.
The primary objective of this project was to develop an understanding of the relationship between fracturing, faulting, and associated stresses within the Woodford Shale in the subsurface and in outcrop. A 3D seismic volume, 2D seismic lines, and an outcrop was correlated by mapping the Wapanucka and Woodford seismic horizons. The seismic data was validated with extensive well control and a synthetic tie. The data was then tied to the outcrop along an arbitrary cross-section line.
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Dr. Roger Slatt of the School of Geology and Geophysics, University of Oklahoma; Dr. Bill Coffey and Rod Gertson of Devon Energy.