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U.S. Geological Survey Open-File Report 2005-1443

Evidence for Cambrian Petroleum Source Rocks in the Rome Trough of West Virginia and Kentucky, Appalachian Basin

Published 2005
Version 1.0

Robert T. Ryder, David C. Harris, Paul Gerome, Tim J. Hainsworth, Robert C. Burruss, Paul G. Lillis, Daniel M. Jarvie, and Mark J. Pawlewicz


The Utica-Lower Paleozoic total petroleum system in the Appalachian basin as defined by Milici and others (2003a,b) is moderately well documented by geochemical evidence (Drozd and Cole, 1994; Ryder and others, 1998). The Middle Ordovician Utica Shale is the source rock in the petroleum system and very likely accounts for oil and gas trapped in such reservoirs as the Cambrian Knox Dolomite, Cambrian Rose Run Sandstone, Lower Ordovician Beekmantown Dolomite, and Middle Ordovician Black River/Trenton Limestones. Probable, but less certain, oil and gas accumulations associated with the Utica Shale source rock are those trapped in the Upper Ordovician Bald Eagle Sandstone/Queenston Shale, Lower Silurian “Clinton/Medina/Tuscarora sandstones, and Upper Silurian Lockport Dolomite.

Hypothetical migration pathways for Utica-derived petroleum were suggested by Ryder and others (1998) along a regional geologic cross section through eastern Ohio and western West Virginia. In addition, this cross section of Ryder and others (1998) showed natural gas occurrences in Cambrian strata of the deep Rome trough of West Virginia (Exxon No.1 McCoy and Exxon No.1 Gainer-Lee wells) that cannot be explained by derivation from a Utica source rock. Rome trough petroleum occurrences in West Virginia and Kentucky include: 1) the Exxon No. 1 McCoy well, Jackson County, West Virginia, where gas from the Cambrian Maryville Limestone of the Conasauga Group initially produced natural gas at 6 to 9 million cu ft per day (Harris and Drahavzal, 1996); 2) the Exxon No. 1 Gainer-Lee well, Calhoun County, West Virginia, where 13.4 barrels of gas-cut mud were produced during a drill stem test from the Maryville Limestone; 3) the Inland No. 529 White well, Boyd County, Kentucky, where 10,000 barrels of oil and associated gas were produced from the Cambrian Tomstown (Maryville Limestone) (Weaver and McGuire, 1977); 4) the Homer field, Elliott County, Kentucky, where gas and oil is produced from the Cambrian Rome Formation and Conasauga Group (Lynch and others, 1999; Harris and others, 2004); and 5) the Miller No. 1 Bailey well, Wolfe County, Kentucky, where good gas and condensate shows occurred in the Cambrian Rome Formation. Although Cambrian source rocks were suspected for these Rome trough gas and oil occurrences, most rock samples analyzed from the Lower Ordovician-Cambrian interval in the trough had a total organic carbon content in weight percent (TOC) that was too low for an effective source rock (Ryder and others, 1998).

New geochemical evidence presented by Ryder and others (2003) indicated that Cambrian source rocks are present in the Rome trough and they correlate favorably with oils in nearby Cambrian reservoirs. This evidence confirms a new petroleum system in the Rome trough of Kentucky and West Virginia that involves a source rock in the Cambrian Conasauga Group and reservoirs in the Cambrian Rome Formation and Conasauga Group (Milici and others, 2003a,b). This report provides the supporting documentation for the Ryder and others (2003) presentation.


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For scientific questions or comments concerning this report, contact Robert T. Ryder.

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