Stratigraphic Sequence of Transgressive Barrier Bar Complex and Model for Hydrocarbon Exploration, Red Fork Sandstone, Wakita Trend, Grant County, Oklahoma: ABSTRACT

Abstract

The Desmoinesian Red Fork sandstone (Boggy Formation, Krebs Group), on the northern shelf of the Anadarko basin, Oklahoma, represents a transgressive barrier bar system. The base of the Red Fork interval is marked by the Inola Limestone (Boggy Formation); the top is marked by the Tiawah (Pink) Limestone (Senora Formation, Cabaniss Group). Upper shoreface and foreshore deposits, in which porosity and permeability range from 8 to 18% and 0.03 to 9.7 md, respectively, produce significant amounts of oil and natural gas along the east-west Wakita trend. Effective porosity (mainly secondary dissolution porosity) is well developed in these deposits. Successful hydrocarbon exploration requires a solid understanding of the stratigraphic sequences and depositional environments within the barrier system. Cored sequences, from bottom to top, include: (1) Inola biomicrite, containing brachiopod, trilobite, and echinoderm fragments, and worm tubes (shallow marine); (2) black fossiliferous shale and nonfossiliferous variegated claystone (lagoonal. open marine); (3) coarsening upward sequences of fine to medium-grained sandstone showing low-angle (< 15/sup 0/) bidirectional cross-stratification and flat laminae (shoreface to foreshore); and, locally, (4) very fine-grained sandstone showing flaser and current-ripple laminae (sand flats). Enclosed in the inferred shoreface or foreshore deposits is a local, 1-ft-thick, flat-laminated, very fine-grained sandstone thatmore » may represent washover deposits. Lateral facies equivalents of the shoreface and foreshore deposits include ripple-laminated, very fine-grained sandstone, some of which is overlain by glauconitic siltstone and shale (back barrier or lower shoreface.).« less