The Anadarko “Super” Basin: 10 key characteristics to understand its productivity

Abstract

More than 50 basins worldwide are identified as “super basins,” defined as a basin with cumulative production of at least 5 billion BOE (∼0.8 billion m3) and with future production potential of more than 5 billion BOE. By this definition, the Anadarko Basin is a super basin; cumulative production is close to 50 billion BOE (∼7.9 billion m3) and unconventional reservoirs have the potential to produce another 50 billion BOE. At least 10 characteristics justify classification of the Anadarko Basin as “super,” namely, 8 key geologic elements and 2 technical and surface characteristics. First, the most important characteristic of a super basin is its source rocks. The Woodford Shale is the dominant source rock in the Anadarko Basin. It has generated and expelled more than 300 billion BOE (more than 47.7 billion m3). Second, the basin was initiated by a failed rift in the late Precambrian–middle Cambrian. Third, the basin was filled with 40,000 ft of Paleozoic strata and multiple reservoirs. Fourth, because of the absence of significant structural inversion in the basin proper, source rocks and migrated oil and gas are mostly mature and relatively predictable with regard to depth of generation. Fifth, a critically important attribute is the left-lateral, north-south basement strike-slip fault system. Sixth, these faults and related fractures along with unconformities and laterally continuous reservoirs provide abundant migration pathways to good regional and local seals. Consequently, the number of accumulations of petroleum is very large and the styles of traps are numerous and varied. Seventh, among the attributes that make the basin productive are numerous cells of overpressured strata and, eighth, an overall paragenetic history that resulted in the development of porous reservoirs. The ninth and tenth features are technological advances and surface conditions, respectively. As a result, the Anadarko Basin has a history of significant conventional oil and gas production and a bright promise of significant nonconventional production.