Evidence for Cambrian petroleum source rocks in the Rome trough of West Virginia and Kentucky, Appalachian basin

Professional Paper 1708-G.8
By: , and 
Edited by: Leslie F. Ruppert and Robert T. Ryder

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Abstract

A 130-foot-thick Cambrian black shale sampled from a core between 11,150 and 11,195 feet in the Exxon No. 1 Smith well in Wayne County, W. Va., has been identified as a good to very good source rock. The black shale is located in the Middle Cambrian Rogersville Shale of the Conasauga Group. Total organic carbon (TOC) values of four samples that range from 1.2 to 4.4 weight percent (average 2.6 weight percent) are the highest reported to date in the pre-Knox section of the Rome trough. Although the samples are probably in the zone of gas generation based on their low hydrogen index values (55 to 63) and temperature maximum of second hydrocarbon peak (S2) values of about 465°C, first hydrocarbon peak (S1) values of 0.81 to 2.71 indicate that they contain free extractable hydrocarbons. A bitumen sample extracted from the Rogersville Shale is characterized by (1) a broad spectrum of n-alkanes from n-C11 through n-C30, (2) strong odd-carbon predominance in the n-C13 to n-C19 range, and (3) small but detectable amounts of isoprenoids pristane and phytane. The strong odd-carbon predominance of the n-C15 to n-C19 n-alkanes is commonly attributed to the Ordovician alga Gloeocapsomorpha prisca. This occurrence of G. prisca is among the first to be reported in Cambrian rocks. Thin black shale beds collected from the Lower to Middle Cambrian Rome Formation in the Texaco No. 1 Kirby well in Garrard County, Ky., have TOC values as high as 3.2 percent, hydrogen index values as high as 417, and bitumen extract characteristics similar to the Rogersville Shale.

The bitumen extract from the Rogersville Shale compares very closely with oils or condensates from Cambrian reservoirs in the Carson Associates No. 1 Kazee well, Homer gas field, Elliott County, Ky.; the Inland No. 529 White well, Boyd County, Ky.; and the Miller No. 1 well, Wolfe County, Ky. These favorable oil-source rock correlations suggest a new petroleum system in the Appalachian basin that is characterized by a Conasauga Group source rock and Rome Formation and Conasauga Group reservoirs. This petroleum system probably extends along the Rome trough from eastern Kentucky to at least central West Virginia.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Evidence for Cambrian petroleum source rocks in the Rome trough of West Virginia and Kentucky, Appalachian basin
Series title Professional Paper
Series number 1708
Chapter G.8
DOI 10.3133/pp1708G.8
Year Published 2014
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Contributing office(s) Eastern Energy Resources Science Center
Description v, 36 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Coal and petroleum resources in the Appalachian basin: distribution, geologic framework, and geochemical character (Professional Paper 1708)
Country United States
State Kentucky, West Virginia
Other Geospatial Appalachian basin
Online Only (Y/N) Y
Additional Online Files (Y/N) N
Google Analytic Metrics Metrics page
Additional publication details