Deep-Water Carbonates: Buildups, Turbidites, Debris Flows and Chalks—A Core Workshop

Deep-water carbonates represent on the few frontiers remaining for carbonate exploration and research. The last decade has experienced a rapid evolution in concepts of depositional models and diagenesis which underscores the importance of these deposits as significant reservoirs and source rocks. This workshop displayed cores selected to provide subsurface geologic examples of deepwater carbonates from a variety of depositional settings. Several papers discuss depositional models, platform-to-basin reconstructions, and diagenetic sequences that are important in the development and exploration of Paleozoic carbonate debris flow and turbidite reservoirs of the Palo Duro, Delaware and Midland Basins. Many other examples are included from several different regions.
Pennsylvanian Carbonate Slope and Basin Deposition, Palo Duro Basin Available to Purchase
-
Published:January 01, 1985
Abstract
Reconstruction of a Pennsylvanian carbonate platform-to-basin complex is presented from well logs for the eastern margin of the Palo Duro Basin. Well-log character and core data indicate carbonate facies, most likely constructed of phylloid algal bioherms and biointraclastic fusulinid lime sands, dominated the platform margin. Lower slope and basin lithologies reflect episodic deposition of carbonates and shales. The alternating carbonate-shale cycles occur in the lower slope and basin as discrete basinward thinning wedges.
Post-carbonate basin-filling shales preserved the platform-to-basin profile, which had a depth of nearly 200 meters. Turbidites and debris flows transported predominately platform margin sediments down a slope of 3-4 degrees that varies in width between 4.8-8.8 kilometers. The entire wedge of carbonate clastics extends 11 kilometers into the the basin from the platform margin.
The wedge consists of amalgamated mud-rich biolithoclastic and lithoclastic floatstones and rudstones, and porous biolithoclastic rudstones-grainstones and bioclastic packstones-grainstones. Sediment textures suggest deposition from debris flows and turbidity currents. The latter lithology represents the prospective reservoir facies in the basin. Porosity occurs in preserved intraskeletal, cement-reduced primary intergranular, and secondary dissolution of phylloid algal plates.