Abstract: Oil and Gas Potential of Los Padres National Forest, California

Thomas E. Hopps, Leonard T. Stitt

Los Padres National Forest (LPNF) occupies portions of the Coast and Transverse Ranges between Monterey and Gorman, California. High potential exists for the discovery of commercial quantities of oil and gas around the forest perimeter; much lower potential for such discoveries exists throughout most of the rest of the forest.

LPNF is comprised principally of lower Tertiary and older sedimentary rocks with crystalline basement exposed at its northern and eastern ends. The forest overlaps major oil producing basins containing thick sequences of upper Tertiary sediments.

Forest terrane south of Santa Ynez fault exhibits an east-west structural grain. Most of the remainder of LPNF exhibits a pronounced northwest-southeast structural grain. Folds range from vertical and overturned structures to broad, upright features that commonly persist for miles.

Approximately 195 exploratory wells have been drilled within LPNF. Most of the reported shows occurred in Neogene strata of the surrounding basins. In Ventura Basin, shows were also reported from Paleogene rocks. Sespe and South Cuyama oil fields produced 769,000 equivalent bbl of oil from LPNF leases during 1992.

Within LPNF, the potential for discovering commercial quantities of oil or gas in Cretaceous strata is very low. Paleogene strata offer low potential for such discoveries throughout most of the forest, but high potential near Sespe oil field. Potential from Neogene strata is moderate in the interior portion of the forest, but high where Miocene reservoirs are trapped beneath older strata around its perimeter.

Of the nine high potential areas outlined in this study, South Cuyama, San Cayetano, and Sespe areas clearly have the greatest potential for the discovery of significant quantities of hydrocarbons.

AAPG Search and Discovery Article #90981©1994 AAPG Pacific Section Meeting, Ventura, California, April 27-29, 1994