--> Abstract: Double A Wells Field - A Prolific "Sleeper" in the Downdip Woodbine Trend in Texas, by F. L. Stricklin, Jr.; #90932 (1998).

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Abstract: Double A Wells Field - A Prolific "Sleeper" in the Downdip Woodbine Trend in Texas

STRICKLIN, FRED L., JR.
Exploration Trend Analyses, The Woodlands, TX

Preeminence of Woodbine sandstones as lucrative exploration targets has once again been underscored by the development of Double A Wells Field in Polk County, Texas. Twenty-eight wells, completed mostly since 1992 in overpressured reservoirs, have already produced 140 BCFG and 8 MMBC - less than 1/2 of its initial reserves.

The alignment of the field with other fields updip records the trace of a stream that originated on the Sabine Uplift and flowed in a sand-transport channel across the marine shelf and onto the slope. Studies indicate that the transported sands were deposited in the following settings: Damascus - delta front; Hortense - upper slope turbidite fan, and Double A Wells - mid-slope turbidite fan.

The trap is a sandstone pinchout on a structural nose. The pinchout is along a discontinuity that separates a seaward offlapping sequence from an overlying landward onlapping sequence, as identified seismically. The pinchout then may result from marine erosion of sand remaining in the feeder channel and its replacement by shale affording an updip seal.

The sandstone reservoir sequence, beneath an intervening 20-40 ft. of Rapides Shale, is overlain by organic-rich, Austin-age lime mudstone comprised largely of debris of pelagic nannofossils. This source rock conforms in its lenticular configuration with that of a 4 sq mi "sweet spot" in the underlying reservoir. This superposition of source rock and optimum reservoir comprises an excellent dynamic model of hydrocarbon expulsion presently downcharging through a thin shale cover into a contiguous reservoir. Burial temperature of around 3500 favors the thermal expulsion of wet gas from the source rock.

Other rewarding fields similar to Double A Wells remain to be discovered in the downdip Woodbine trend.

AAPG Search and Discovery Article #90932©1998 GCAGS/GCS-SEPM Meeting, Corpus Christi, Texas