STRUCTURAL GEOLOGY OF THE WOODFORD SHALE IN THE SOUTHEASTERN ANADARKO BASIN, GRADY COUNTY, OKLAHOMA

Abstract

The Anadarko basin, especially the SCOOP (South Central Oklahoma Oil Play) and Merge areas, has become one of the most prospective and successful oil plays in the country. However, there is an increasing need to refine and improve the understanding of the general geological setting of the hydrocarbon producing formations within its boundaries, specifically the role of structure on accumulating and producing oil and gas. The Devonian Woodford shale unconventional reservoir of the Anadarko basin is one of the main targets for exploration and production. It has been previously studied with a focus on its stratigraphy, geomechanics and geochemistry but not much about its structural geology. Most of the structural work done has been either at an outcrop level or at the state level. This thesis uses well log analysis, 2-D seismic interpretation and well core observations to help define formation tops and construct cross sections and structural maps to provide a better developed structural framework for this productive area that comprises the northern limits of the SCOOP play and the transitional Merge play in Grady County, Oklahoma. The resulting structural map for the Woodford shale features two structurally different regions. The first is a structurally stable region, with almost no faulting towards the central and northern part of the county and the second region, mainly in the southern half of the county is a more structurally complex region. This work also combines this structural framework of the Woodford shale in the Grady County area with available production data to analyze and suggest that the gas production follows closely the structural setting of producing wells; increasing in the structurally stable zone and decreasing in areas with a higher number of faults. Oil production does not appear to be related to faults