The Sacramento basin occupies the northern half of the Great Valley of California. It is a long, narrow asymmetric basin, with a steep west flank and a broad, shallow east flank. Sediments range in age from Jurassic to Holocene, with essentially dry gas production coming from sediments of Late Cretaceous, Paleocene, and Eocene age. The basin can be divided into four areas: the northern San Joaquin, Delta, Suisun, and northern Sacramento areas.

In the northern San Joaquin area, production has come from anticlinal closures, mostly along the upthrown sides of two major faults. Future production probably also will be located on anticlinal highs.

In the Delta area, production has come from anticlines, fault traps, some stratigraphic traps, and traps against two major gorges. Future production will probably be found in fault and gorge traps. Production in the Suisun area has been located on anticlines. Future production may come from presently unknown anticlines and from new pools found on known anticlinal trends.

In the northern Sacramento area, production has come mostly from stratigraphic traps in sandstone of the Forbes Formation, with additional production from anticlinal trends and from domes overlying buried volcanic plugs. Future production will probably be from Forbes stratigraphic traps.

Over half the gas in the Sacramento basin probably has been discovered. Future exploration will be concentrated in the Delta and northern Sacramento areas. It is possible, but doubtful, that future major production may come from formations deeper than those presently productive, and from parts of the basin presently considered nonprospective.

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