The Upper Devonian Rhinestreet Black Shale of Western New
THE UPPER DEVONIAN RHINESTREET BLACK SHALE OF WESTERN NEW YORK STATE- EVOLUTION OF A HYDROCARBON SYSTEM GARY G. LASH Department of Geosciences State University College Fredonia, NY 14063 USA and DAVID R. BLOOD Chesapeake Appalachia L.L.C. Charleston, WV INTRODUCTION Organic-rich, low permeability, sometimes fractured, shale deposits, once ignored by drillers seeking more readily understood plays and faster returns on their investments, are boosting the fortunes of midsized producers across the United States and becoming an increasingly important resource base. This burgeon ing interest is driven largely by increased natural gas prices, improved completion technologies and a lack of conventional reservoir targets. However, there is no universal model applicable to each and every unconventional or continuous-type reservoir. Indeed, most vary in terms of basic stratigraphic facies distribution, mineralogy (i.e., quartz content and clay type and content), fracture parameters (length, orthogonal spacing, connectivity, anisotropy), porosity and permeability, and rock mechanical properties. There clearly is a need to further our understanding of these economically important deposits. This field trip focuses on the evolution of the heavily fractured Upper Devonian Rhinestreet black shale, which has served not only as a hydrocarbon source rock, but also as its own seal and reservoir, the essence of the unconventional reservoir. Specifically, we address the Rhine street shale in terms of the hydrocarbon system, which comprises three basic elements (Demaison and Huizinga, 1994). The first component, charge, is the hydrocarbon volume available for entrapment and is dependent upon source rock richness and volume. Migration, the second parameter, can be thought of in terms of the lateral movement of hydrocarbons via permeable carrier beds versus vertical migration via faults and, more to the point of the Rhinestreet shale, fractures.
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