STRATIGRAPHY AND SEDIMENTARY DYNAMICS OF THE DESMOINESIAN CHEROKEE GROUP, DEEP ANADARKO BASIN, TEXAS PANHANDLE

To explore for and develop deep-water sedimentary gravity-flow related deposits as hydrocarbon reservoirs, their stratal architecture and spatial heterogeneity must be understood. The Cherokee Group in the Anadarko Basin, northeastern Texas Panhandle, provides an opportunity to investigate an icehouse to greenhouse Pennsylvanian hybrid system that well demonstrates the intricacies of vertical and lateral facies relationships in an unconfined fan-delta fed deep-water slope to basinal setting. The stratigraphic section ranges in thickness from 150 to 460 m. The cyclic sedimentation and foreland basin tectonics resulted in a complex stratal architecture that was sourced by multiple areas of sediment input.

This investigation consists of wireline-log and core data. Five-thousand wireline logs were correlated in an area of over 9500 sq km to map out six depositional sequences that are separated by major flooding events. These events are correlative over the whole area of study. Six cores, that sample nearly the complete section, were described for lithofacies based on depositional features and mineralogy. Nine lithofacies were recognized through core description and petrographic study: (1) Sub-arkosic sandstone, (2) Sandy siliciclastic conglomerate, (3) Muddy calcareous conglomerate, (5) Crinoidal packstone, (6) Oodic grainstone, (7)Pelodic grainstone, (7) Organic poor very fine to fine laminated mudstone, (8) Organic rich faint laminated mudstone, (9) Ripple laminated mudrock. Thin-to-thick bedded turbidites, hyperconcentrated density flow deposits (slurry beds), and debris and mud flow deposits were observed. The integration of isopachs of the depositional sequences with the lithofacies has allowed the delineation of the spatial and temporal evolution of the slope to basin-floor system. The sediment-water interface condition during sediment deposition was defined by X-Ray Fluorescence based Chemostratigraphy. These mixed siliciclastic (subarkoses and lithicarkoses) and carbonate deposits can be carrier beds for the hydrocarbons generated from the enclosing organic-rich (TOC ranges from 0.55 to 6.77%), dysareobic to anaerobic mudstones.