AAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Geology and Assessment of Undiscovered Oil and Gas Resources in the Arbuckle Group, Anadarko Basin, USA: Where is the Potential?
(1) U.S. Geological Survey, Denver, CO.
The U.S. Geological Survey (USGS) recently assessed the technically recoverable undiscovered oil and gas resources from the Anadarko Basin of Colorado, Kansas, Oklahoma and Texas. The assessment includes detailed stratigraphic and structural framework studies, petroleum system modeling, and historical exploration data and production analyses that are applicable to resource estimation. Using this approach, the USGS defined two total petroleum systems (TPS) in the Anadarko Basin that contain nine conventional assessment units (AU) and two continuous (unconventional) AUs.
The Woodford Composite TPS contains Cambrian- through Mississippian-aged strata and is defined as the area which contains current and potential petroleum resources for each AU, including the Arbuckle-Ellenburger AU. The extent of the Arbuckle-Ellenburger AU is constrained to the north and west by the Anadarko Basin province boundary, to the south by the Arbuckle-Ellenburger Group subcrop along the Precambrian fault system, to the east by the Nemaha uplift, and to the northeast by the NW-SE fault system that defines the southeastern extent of the Central Kansas uplift. Production is commonly structurally controlled, though porosity development is enhanced by karstification, fracturing or late diagenesis. The best production within the AU is associated with late dolomitization of the Arbuckle Group on the Anadarko Basin shelf. Oil and gas have been produced from carbonates of the Arbuckle Group in a variety of settings throughout Oklahoma, Kansas and the Texas panhandle. The majority of the exploration and production is focused along structures in the eastern and southern part of the basin and in the upper 250 feet of the Arbuckle Group. There is a large area in the deep Anadarko Basin that is mostly unexplored. Woodford Shale vitrinite reflectance values in this area are >1%, though the Woodford Shale would probably only contribute updip of the subcrop edges of the Woodford Shale due to migration. There may be potential source rocks deeper than the Woodford in this part of the basin, as has been suggested, but debated for the Arbuckle, Simpson, and Viola Groups. Burial history 1-D models calibrated to temperature and vitrinite reflectance data suggest that potential Arbuckle Group source rocks started generating oil ~350 Ma in the deep basin and are still within the oil generation window on the Arbuckle Group’s shelf.