Stratigraphic and Structural Controls of Natural Gas Production from the Berea Sandstone (Mississippian), Southwestern Virginia

Abstract

The Berea Sandstone, a major reservoir 5000 ft beneath the Virginia plateau, produces nonassociated gas, from west to east, from the Roaring Fork, Nora, Glick, and Berwind trends. Production generally is stratigraphically controlled, but may be structurally enhanced in the Berwind trend on the southwest-plunging Dry Fork anticline. The Berea is within a shale sequence and grades generally from sandstone to siltstone westward. Production in Roaring Fork coincides approximately with relatively small areas of slightly greater siltstone thickness. The Nora and Glick trends, major northeast-extending zones as much as 150 and 60 ft thick, respectively, are 14 mi apart, 10 mi across, and up to 30 mi long. These trends are parallel to the Mississippian paleoshoreline and contain prodelta sediments that accumulated at or below wave base. In the Nora trend, the Berea produces where it is greater than 60 ft thick. Initial well-head pressures generally range from 500 to 800 lb/in[sup 2], and final open flows commonly range up to 1400 MCFD, with the maximum reported as 4992 MCFD. Eastward toward the source of sediment, as little as 40 ft of Berea produce gas in the Glick and Berwind fields. Initial open flows increase eastward, reflecting increases in grainmore » size, porosity, permeability, and perhaps in fractures. In the Nora trend, natural open flows for 10% of the wells exceed 150 MCFD; in the Glick and Berwind fields, open flows for 30 and 60% of the wells, exceed 150 MCFD.« less