The Sacramento Valley is the north half of the Great Valley of California and lies between the Sierra Nevada and Coast Ranges geomorphic provinces. This gas province produces from Upper Cretaceous and Tertiary sandstone deposited in a miogeosynclinal basin. Four tectonic episodes provided structural and stratigraphic complexities that form gas traps today.

Economic conditions tied to the regulated status of the gas market have controlled the rate of new-field discoveries in the past and will do so in the future. Cumulative production is 4.267 trillion cu ft and proved gas reserves are 2.445 trillion cu ft. Economic conditions are expected to improve as market demand provides renewed incentive to explore.

The basin appears to be near the midpoint in its productive life. Many new fields can be expected in presently producing formations, but there is less hope for major accumulations in younger or older rocks. Major structural trends have been delineated, and deeper production is expected along these trends, as well as more subtle structural and stratigraphic traps.

New discoveries are anticipated for the next 25 years, and production should continue into the next century. The estimate of undiscovered recoverable reserves, based on an analysis of currently producing formations, is 4.658 trillion cu ft. If an average recovery factor of 80 percent is assumed, the volume of undiscovered gas in place is estimated to be 5.822 trillion cu ft. The potential of the vast thicknesses of older rocks is largely unknown, and it would be a mistake either to ignore this section or to assign large volumes of reserves to it.