Pyrolysis and Hydrocarbon Source Bed Potential of the Upper Devonian Woodford Shale, Hovey Channel, Southern Permian Basin, West Texas

HUSSAIN, MAHBUB, and MARK A. BLOOM, Sul Ross State University, Alpine, TX

The Upper Devonian Woodford Shale in the Hovey Channel area, southern Permian basin, is 50 m thick and composed largely of brown to black, pyritic, spore-bearing, organic-rich, fissile shale and chert. Total organic carbon, distillable hydrocarbons, genetic potential, organic carbon index, hydrogen index, temperature of maximum hydrocarbon generation, and kerogen transformation index of the Woodford Shale suggest a matured to overmatured, gas-generating source bed.

The total organic carbon content of the formation ranged from a low of 0.77% in the cherty samples to a high of 4.59% in a shaley sample, averaging 2.18%. Distillable hydrocarbon content of the samples is fairly high (averaging 1.72 mg HC/gm degrees rock), varying from 0.90 mg HC/gm degrees rock to 3.22 mg HC/gm degrees rock. Genetic potential evaluated in terms of both residual and total generative potential showed above average potential, averaging 3.25 mg HC/gm degrees rock for the residual and 4.90 mg HC/gm degrees rock for the total, respectively. Live organic carbon index values ranged from 11-28%, characterizing the formation as a moderate to good source bed. Hydrogen index values ranged from 73 mg HC/gm degrees C org to 155 mg HC/gm degrees C org, suggesting overmaturity and g s-generation potential of the source bed. Temperature of maximum hydrocarbon generation values and kerogen transformation ratio values (averaging 0.34) also indicate overmatured nature of the Woodford Shale.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)