USGS Estimates 21 Million Barrels of Oil and 27 Billion Cubic Feet of Gas in the Monterey Formation of the San Joaquin Basin, California

The U.S. Geological Survey recently completed its first assessment of continuous resources in the Monterey Formation in California’s San Joaquin Basin, estimating mean volumes of 21 million barrels of oil, 27 billion cubic feet of gas, and 1 million barrels of natural gas liquids.

The volume estimated in the Monterey Formation is small, compared to previous USGS estimates of conventional resources in the San Joaquin. The assessment team concluded that part of the reason for this is that most of the petroleum that originated in the Monterey Formation has escaped and migrated to fill the shallower conventional reservoirs. As a result, most exploratory wells in the deep basin are unlikely to be successful.
This assessment only covered the oil and gas generating portions of the Monterey Formation in the San Joaquin Basin. Other portions of the Monterey can be found in the nearby Los Angeles, Santa Maria, and Ventura Basins. USGS is assessing the oil and gas generating portions of the Monterey in those Basins and will publish those as soon as the studies are complete.
A map showing the extent of the San Joaquin Basin, as well as the location of the two assessment units of the Monterey Formation that were included.