Title: NATURAL GAS FROM TIGHT SILTSTONES IN THE CATSKILL CLASTIC WEDGE IN WEST VIRGINIA
Abstract: Stratigraphic studies of Middle and Upper Devonian rocks in West Virginia suggest that thick zones of interbedded siltstone and shale present between the Devonian Shale gas fields in southwestern West Virginia, and the gas fields in Upper Devonian sandstones and siltstones in central and eastern West Virginia may contain important reserves of natural gas. Wells drilled into these zones of interbedded siltstone and shale should be completed in the same way as wells drilled into the black shales; i.e., the entire zone should be fractured, not selected siltstones.Introduction. During much of Middle and Late Devonian time, the Appalachian Basin was covered by a shallow epicontinental sea. This sea was bordered on the east by a land area that supplied the large amount of clastic sediments that formed the Catskill clastic wedge in the eastern part of the sea. To the west, north, and south, the sea encroached upon low-lying parts of the interior of the continent. Figure 1 parts of the interior of the continent. Figure 1 shows the location of the Appalachian Basin and some of the structural elements associated with it.For the purpose of this paper, rocks in the Cat-skill clastic wedge are divided into three facies:red beds;gray shale and sandstone; anddark-gray shale and siltstone.Facies 1 contains red, gray, and green shale, siltstone, sand-stone, and conglomerate deposited in terrestrial and near-shore marine environments. This facies forms the Hampshire Formation and the uppermost part of the Greenland Gap Group. The facies is present in the eastern and upper part of the clastic wedge (Fig. 2). The Fifth, Bayard, Gantz, Fifty-foot, and Gordon are some of the sandstones in this facies. They have produced significant amounts of oil and gas in northern produced significant amounts of oil and gas in northern West Virginia.Facies 2 contains gray shale, sandstone, and some siltstone. These rocks were deposited in a shallow to moderately deep marine environment west of facies 1. This facies roughly corresponds to the
Publication Year: 1980
Publication Date: 1980-05-01
Language: en
Type: article
Indexed In: ['crossref']
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