ABSTRACT: Understanding Stratigraphic Heterogeneity within the Jacksonburg Stringtown Oilfield, West Virginia, USA: Crucial for Waterflood Success
MATCHEN, DAVID L., MCDOWELL, R. R., AVARY, K. L., and HOHN, M. E., West Virginia Geological and Economic Survey, Morgantown, WV
The Jacksonburg-Stringtown field, discovered in 1895, is the largest active oil field in West Virginia. 13 MMbo were recovered from the Upper Devonian Gordon sandstone reservoir prior to the initiation of waterflooding in 1991; since then, an additional 1.86 MMbo have been produced. Early water breakthrough, unexpected increases in reservoir pressure, and poorer than predicted production appear related to reservoir heterogeneity. The Gordon is a strandplain deposit averaging nearly 50 feet in thickness. Pay rarely exceeds 20 feet and is typically less than 5 feet thick. The lower part of the Gordon consists of fine- to very fine-grained sandstones with few identifiable sedimentary structures and rare, single-quartz-pebble layers. The upper part consists of fine- to very fine-grained sandstone interbedded with conglomerate. Enclosing sediments consist of heavily bioturbated siltstone, very fine-grained sandstone, and shale. In general, Gordon deposition appears to represent nearshore-marine reworking of fluvial sediment.
The most consistent stratigraphic correlation has been achieved using the uppermost and lowermost Gordon sandstones, which are separated by a consistent interval thickness across the field. Pay sandstones are commonly found within either of these two stratigraphic units and are rarely as thick as the enclosing unit. There is good communication within individual pay sandstones but little communication between them. The upper pay sandstone appears best suited for secondary recovery. This work was funded by the U.S. Department of Energy under contract number DE-AC26-98BC15104.
Search and Discovery Article #90907©2000 AAPG Eastern Section Meeting, London, Ontario, Canada