Carpinteria Offshore Oil Field: Structure and Stratigraphy Relationship to Production and Reservoir Quality

Gary A. Younse

The Carpinteria Offshore oil field, a milestone in opening up federal waters in the Santa Barbara Channel for petroleum exploitation, is located in the Santa Barbara Channel 4 mi south of Carpinteria. The field has produced 80 million bbl of oil since its discovery in 1966. Production is the result of hydrocarbon entrapment within an east-west-trending anticline that plunges gently to the east. Production comes from two pools, a main pool resulting from anticlinal closure on the hanging wall block and a subthrust pool in a footwall block under the south-dipping Hobson thrust fault. The anticline is also modified by cross faults that have compartmentalized deformation and produced secondary fault-block traps. A closer look at the secondary fault blocks shows further entrap ent via imbricate faults relative to the Hobson thrust fault, locally resulting in stacked reservoirs.

The vertical sequence of Pliocene reservoir rocks offers a good opportunity to study deep-water marine turbidite sandstones, which comprised a progradational submarine fan complex apparently sourced from the east. Productive intervals can be assigned to specific fan facies based on E-log signatures and lithology. Reservoir character inherent from specific fan facies is reflected in recoverability of oil from individual productive intervals.

AAPG Search and Discovery Article #91035©1988 AAPG-SEPM-SEG Pacific Sections and SPWLA Annual Convention, Santa Barbara, California, 17-19 April 1988.