Natural Gas Productivity of the Devonian Huron Member of the Ohio Shale in Virginia

Catherine B. Enomoto
Virginia Department of Mines, Minerals and Energy, Division of Geology and Mineral Resources, Charlottesville, VA 22903, [email protected]

In 2007, 23.5 billion cubic feet of natural gas were produced from Mississippian sandstone and limestone, and from Devonian shale in the Appalachian Plateaus Province in Virginia. The dominant Devonian shale from which natural gas was produced is the lower Huron Member of the Ohio Shale. The lower Huron is productive in six counties in southwest Virginia. In these six counties, the measured depth of the lower Huron member of the Ohio Shale ranges from 2700 to 7039 feet below ground surface. The apparent thickness of the lower Huron ranges from zero to 437 feet. In much of the productive area, gamma ray measurements of the lower Huron indicate two anomalously high zones separated by a zone of lower gamma ray values. These variable gamma ray zones of the lower Huron member are relevant to planning well completion programs for vertical and horizontal wells in this formation.

Between 2006 and 2008, gas and oil operators in Virginia completed more than 100 vertical wells in the lower Huron member of the Ohio Shale. The completion flow rates in these wells were commingled with other formations, so the rates explicitly from the lower Huron cannot be determined from completion reports. One horizontal well was completed in the lower Huron in 2008. In this well, four zones were perforated and treated with nitrogen, and the combined initial flow rate reported was 725,000 cubic feet per day.

AAPG Search and Discovery Article #90095©2009 AAPG Eastern Section Meeting, Evansville, Indiana, September 20-22, 2009