Oil Fields of the Santa Maria Basin and Adjacent Offshore Areas, California

Santa Barbara County has two major oil-producing areas; the Santa Maria Basin and the Santa Barbara Channel. Although the Santa Barbara Channel is the offshore extension of the Ventura Basin, the two basins merge offshore Point Arguello and the oil fields in the western Santa Barbara Channel are more similar to the Santa Maria Basin fields than to the fields in the onshore Ventura Basin.

The Monterey Shale of Miocene age is the source of nearly all of California's oil, but in the Santa Maria Basin and the Santa Barbara Channel it is also the dominant reservoir. Oil is produced from fractured cherts and, more importantly, dolomite beds within the Monterey Formation. Most of the Monterey Formation was originally diatomite, but it has been altered to chert or an intermediate phase rich in opal and cristobalite.

2003 Oil Production

The onshore Santa Maria Basin produced 1.84 million barrels of oil in 2003. Orcutt was the most productive onshore field. Offshore Santa Barbara County, including federal waters, produced 27.38 million barrels of oil in 2003. Hondo was the most important offshore field, followed by Pescado and Point Arguello.

Undeveloped Offshore Oil Fields

Several large, undeveloped offshore fields are shown on the map below. Most of these fields are north of Point Concepcion and are heavy oil. The drop in oil prices in 1986 may have rendered these fields uneconomical, although recent increases in oil prices combined with improvements in offshore technology make them attractive now. Another factor delaying the development of these fields is strong local opposition to offshore oil development. Three new developments get around this problem by developing new fields from existing platforms with extended-reach wells. Plains Exploration is developing the Rocky Point Field from Platform Hidalgo in Point Arguello Field. Plains has proposed developing the Bonito Field from Platform Irene in Point Pedernales Field and Noble Energy has proposed developing the Sword Field by drilling from a platform in the Point Arguello Field. These fields contain a significant resource for the future.