Thermal maturity of Woodford Shale gas and oil plays, Oklahoma, USA

Being a hydrocarbon source rock and having a brittle (silica-rich) lithologic character makes the Woodford Shale (Late Devonian to Early Mississippian) an important oil and gas shale in Oklahoma. Since 2004, Woodford Shale plays have expanded from producing primarily thermogenic methane in one geologic province to producing thermogenic methane, condensate, oil and biogenic methane in four geologic provinces at thermal maturities from mature (> 0.5% vitrinite reflectance, Ro) to post mature (2% to 3% Ro). Condensate is produced at a thermal maturity up to 1.67% Ro. Oil is produced from naturally-fractured, silica-rich shale. Biogenic methane is produced in shallow (< 2000 ft, 610 m) reservoirs down dip from the outcrop in northeast Oklahoma.

► The Late Devonian-Early Mississippian Woodford Shale contains type II kerogen. ► The marine shale has a brittle (silica-rich) lithologic character. ► The shale produces thermogenic methane, condensate, oil and biogenic methane. ► Condensate is produced at a thermal maturity up to 1.67% Ro. ► Oil is produced from naturally fractured shale.