Geologic Assessment of a Thin Limestone Unconventional Reservoir in The Anadarko Basin, Oklahoma

Abstract

In this geologic assessment of the Jone Limestone I identify and describe the key components of the Jone Limestone hydrocarbon system: The source rock is a dark organic rich shale called the Douglas formation. The Douglas formation is a key source rock in the Anadarko Basin. The hydrocarbons from the Douglas formation migrated to the Jone Limestone during the middle to late Pennsylvanian though faults and fractures. A stratigraphic pinch-out acts as a trap to pool the hydrocarbon in the Jone Limestone. Finally, the Westbrook shale is the seal in the system. A thorough analysis revealed that the most unknown elements of the petroleum system were the reservoir characteristics and the seal. Mapping the reservoir revealed an average reservoir thickness of 8 ft., average porosity 6.7%, average water saturation 55% and an average “hydrocarbon-in-place” value estimated at 1.25 million barrels of oil equivalent (mmboe). A closer look at the seal map revealed areas of potential seal breach. Careful risk analysis revealed that the Jone Limestone is not an economically feasible prospect for drilling new wells, however, the Jone Limestone is a valuable prospect for new hydraulic fracturing in a previously completed well. Jone Limestone recompletion projects creates value through new production, divesture, and lease retention.