STRATIGRAPHY AND GAS PRODUCTION FROM UPPER DEVONIAN BLACK SHALES, WYOMING COUNTY, WEST VIRGINIA

Upper Devonian rocks in central Wyoming County, West Virginia, have been a popular target of hydrocarbon exploration in the past 25 years. The area is east of the classic producing areas of southwestern West Virginia and will continue to be a viable target for the future. Two intervals of black shale are productive: the Huron Member of the Ohio Shale and the Rhinestreet Member of the West Falls Formation. In central Wyoming County only the lower tongue of the Huron Member is recognized. The tongue is a black silty shale with interbeds of gray shale and siltstone. The upper black shale tongues prominent in the west are replaced by non-black shale and siltstone interbeds. Thickness in this area ranges from 200 to 300 feet. The Rhinestreet Member is an interval of black pyritic shale and gray siltstone. The thickness in central Wyoming County ranges from 300 to more than 400 feet. Variations in thickness within the Rhinestreet Member may be due to factors including location of the depocenter, an increase in gray shale and siltstone interbeds in an eastern facies, and possible fault repetition. Most black shale wells in the area produce commingled gas from both intervals rather than individually in order to maximize production and extend the life of the wells.