Abstract: Resistivity of the Mowry Shale as a Source Rock Maturity Indicator

MOREL, JOHN A.

The Mowry shale is present throughout Wyoming and is recognized as a primary hydrocarbon source for the Muddy sandstone. As with most shales, the lithology and pore distribution is such that significant amounts of liquid and gaseous hydrocarbons are retained in the source rock after generation and primary migration have occurred. The retained hydrocarbons produce several physical effects including an increase in resistivity. This investigation documents the relationship of resistivity to the level of maturity for the Mowry shale using Vitrinite reflectance data, Rock-Eval pyrolysis data, and Lopatin style time-temperature models. A generalized map of significant resistivity thresholds was prepared for the Powder River Basin, Wyoming. It is reviewed with respect to producing areas, gas/oil ratios, and the basin centered overpressure cell.

AAPG Search and Discovery Article #90946©1997 AAPG Rocky Mountain Section Meeting, Denver, Colorado