Stratigraphic architecture, depositional systems, lithofacies, and reservoir quality of a deepwater, hybrid mudrock system: Middle Pennsylvanian (early Desmoinesian) Cherokee group, Anadarko Basin, northeast Texas panhandle
The Pennsylvanian Cherokee Group in the western Anadarko Basin (northeast Texas Panhandle) is a possible deepwater-hybrid hydrocarbon system influenced by cyclic sedimentation and foreland basin tectonics. Six cores and greater than 5000 wireline logs are being used construct regional stratigraphic architecture, describe lithofacies and their distribution, interpret depositional systems, and assess the source potential and reservoir quality of this system.
Seven lithofacies are recognized based on depositional features and mineralogy: (1) very fine to fine-grained arkosic sandstone, (2) coarse-grained arkosic sandstone, (3) ripple laminated mudrock, (4) faint-laminated mudrock, (5) fine-laminated mudrock (6) conglomerate, and (7) sandy skeletal limestone. Lithofacies description suggests that deposition appears to be by mass wasting processes ranging from debris-flows to surge-like turbidity flows with potential reworking of sediments by bottom currents in a deepwater fan-apron setting. High TOC values and minor bioturbation suggest a low-oxygenated setting. Using lithofacies and sandstone isopachs, the depositional setting and distribution of sandstones are delineated. XRF-based chemostratigraphy will help define sediment-water interface conditions during deposition.
Rock-Eval analysis indicates that TOC in mudstones have values up to 6 wt%. The mudrocks are source rocks that supplied hydrocarbons to the interbedded coarser-grained deposits. The reservoir architecture and associated reservoir quality of this hybrid unconventional hydrocarbon system will be define and evaluated through the integration of stratigraphy and rock properties.
AAPG Datapages/Search and Discovery Article #90214 © 2015 Southwest Section AAPG Annual Convention, Wichita Falls, Texas, April 11-14, 2015