David L Matchen1, Ronald R McDowell1, Katharine Lee Avary1
(1) West Virginia Geological and Economic Survey, Morgantown, WV
ABSTRACT: Reservoir Characterization of the Gordon Sandstones in Northern West Virginia
The Gordon trend is well defined in southwestern Pennsylvania and northern West Virginia. For a reservoir characterization study of the Gordon in the Jacksonburg-Stringtown oilfield, the distribution of reservoir-quality sandstone within the Gordon was described and mapped. The Gordon was subdivided into three stratigraphic units composed of four distinct lithologies: conglomerate, pay sandstone, non-pay sandstone and shale. Of these, only the pay sandstone was consistently porous and permeable and can be distinguished from the non-pay sandstone by the absence of sedimentary structures. Non-pay sandstone is denser and displays a variety of sedimentary structures. The reservoir in the area appears to be compartmentalized into thin, laterally continuous flow-units separated vertically by low-permeability sandstone and shale. Because of the great distance from the assumed clastic source in the Acadian Mountains, the volume of conglomerate observed in the Gordon was larger than expected. Conglomerates are currently interpreted as a lag formed at the top of the section during a local transgression that forced the shoreline eastward. The conglomerates were probably initially deposited in single pebble layers that were subsequently reworked into a pavement. This is consistent with conditions found at Cape Romain, South Carolina, where thin, well-sorted sandstones migrate landward in response to a local transgressive event and are overlain by lags composed of shell material. The Gordon reservoir in the Stringtown field may be the result of stacking of several small, transgressive sand bars. This work was funded by the U.S. Department of Energy (contract number DE-AC26-98BC15104).
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado