--> ABSTRACT: The Role of Genetic Stratigraphy in Reservoir Characterization of Mixed Siliciclastic/Carbonate Valley-Fill Reservoirs: Example from the Pennsylvanian Wapanucka Limestone and Spiro Sandstone, Arkoma Basin, Southeastern Oklahoma, by B. W. Horn; #91021 (2010)

Datapages, Inc.Print this page

The Role of Genetic Stratigraphy in Reservoir Characterization of Mixed Siliciclastic/Carbonate Valley-Fill Reservoirs: Example from the Pennsylvanian Wapanucka Limestone and Spiro Sandstone, Arkoma Basin, Southeastern Oklahoma

HORN, BRIAN, W.

The Wapanucka Limestone and Spiro sandstone comprise a (3rd order) genetic sequence bounded by deposits and surfaces that record marine deepening. This final stage of passive-margin deposition contains two smaller scale (4th order) mixed carbonate-siliciclastic cycles that record progradation (highstand system tract), valley incisement (lowstand systems tract), valley filling and transgression (transgressive systems tract). Reservoir development within these smaller scale cycles show systematic lateral and vertical variation and compartmentalization that can be attributed to their stratigraphic position within the larger stratigraphic cycle. Core analysis and regional mapping demonstrates the presence of a 4th order regional erosion surface (sequence boundary) which incised 10-60 feet into the underlying Wapanucka shelf carbonate cycles. Progradation of the seaward-stepping clastic sub-Spiro shoreface (HST), created laterally continuous and interconnected reservoirs that are locally truncated by younger "Foster" paleovalleys with 60-140 feet of relief, juxtaposing fluvial-estuarine sandstones and Wapanucka shelf carbonates. In each of the systems tracts, these 4th order cycles show systematic variation in reservoir quality, thickness and compartmentalization that may be related to their position within the larger genetic sequence. Shelf carbonate facies are primarily a non-reservoir unit, whereas the regressive clastic shoreface cycles are productive in the northern part of the basin. While both valley fills contain reservoir quality sandstones, the older Wapanucka valley-fill sandstones form isolated reservoir units in the northern part of the basin. Younger "Foster" valley-fill reservoirs, found across the entire basin, are thicker, contain little carbonate skeletal material and have larger areas of drainage. Comparison of these two valley-fills show differences in reservoir quality, architecture and compartmentalization that can be understood from the context of the stratigraphic position within a stratigraphic hierarchy.

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.