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Thermal maturity patterns (CAI and %Ro) in the Ordovician and Devonian rocks of the Appalachian basin in West Virginia

July 18, 2005

The objective of this study is to enhance existing thermal maturity maps in West Virginia by establishing: 1) new subsurface CAI data points for the Ordovician and Devonian and 2) new %Ro and Rock Eval subsurface data points for Middle and Upper Devonian black shale units. Thermal maturity values for the Ordovician and Devonian strata are of major interest because they contain the source rocks for most of the oil and natural gas resources in the basin. Thermal maturity patterns of the Middle Ordovician Trenton Limestone are evaluated here because they closely approximate those of the overlying Ordovician Utica Shale that is believed to be the source rock for the regional oil and gas accumulation in Lower Silurian sandstones (Ryder and others, 1998) and for natural gas fields in fractured dolomite reservoirs of the Ordovician Black River-Trenton Limestones. Improved CAI-based thermal maturity maps of the Ordovician are important to identify areas of optimum gas generation from the Utica Shale and to provide constraints for interpreting the origin of oil and gas in the Lower Silurian regional accumulation and Ordovician Black River-Trenton fields. Thermal maturity maps of the Devonian will better constrain burial history-petroleum generation models of the Utica Shale, as well as place limitations on the origin of regional oil and gas accumulations in Upper Devonian sandstone and Middle to Upper Devonian black shale.

Citation Information

Publication Year 2005
Title Thermal maturity patterns (CAI and %Ro) in the Ordovician and Devonian rocks of the Appalachian basin in West Virginia
DOI 10.3133/ofr20051078
Authors John E. Repetski, Robert T. Ryder, Katharine Lee Avary, Michael H. Trippi
Publication Type Report
Publication Subtype USGS Numbered Series
Series Title Open-File Report
Series Number 2005-1078
Index ID ofr20051078
Record Source USGS Publications Warehouse
USGS Organization