High-Potential Gas Production and Fracture-Controlled Porosity in Upper Devonian Kane Sand,"Central-Western Pennsylvania: GEOLOGIC NOTE"

Abstract

Cush Cushion field is a small gas-producing tract in central-western Pennsylvania. It lies physiographically within the Pittsburgh Plateau section of the Appalachian Plateau province. The Allegheny Front, which forms the border between the Appalachian Plateau province and the Valley and Ridge province, is 23 mi (37 km) east of the field. Cush Cushion is developed across the Brush Valley synclinal axis in eastern Indiana County. The Conemaugh Group (Pennsylvanian) is exposed at the surface, and production is from the multistory sandstone reservoirs of the Bradford Group (Upper Devonian) at depths ranging from 2600 to 3924 ft (792 to 1196 m). The Kane sand of the lower Bradford Group is the principal reservoir at Cush Cushion field. The Kane is interpreted as a distributary-channel sandstone associated with the westward progradational Catskill clastic wedge. Kane sand production is probably fracture controlled at Cush Cushion field. Surmised fracture porosities as high as 22% occur along a limited east-west trend. Natural open flow of up to 15 mmcfgpd are known from the fractured Kane interval. A zone of structural discontinuity is recognized at Cush Cushion field. Fracture porosity in the Kane may be related to the local disruption of the regional structural grain. Thismore » disruption could represent the extension of a documented cross-structural discontinuity from the overthrust belt into the undetached foreland. 7 figures, 1 table.« less