--> Integration of Geologic and Reservoir Data to Evaluate Future Development of Terminal 7, Upper Miocene Reservoir in Long Beach Unit, Wilmington Oil Field, Los Angeles, California, by Brigitte H. Berman; #91024 (1989)

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Integration of Geologic and Reservoir Data to Evaluate Future Development of Terminal 7, Upper Miocene Reservoir in Long Beach Unit, Wilmington Oil Field, Los Angeles, California

Brigitte H. Berman

The Terminal 7 reservoir is the last of the 35 different reservoirs in the Long Beach unit to be developed. The first well was completed in 1978. Development was delayed because of completion problems posed by multiple oil-water contacts. The original oil in place is estimated at 18.5 million stock tank bbl in the upper and lower Terminal subzone and 4.5 million stock tank bbl in the lower Terminal subzone. The reservoirs consist of a total of 500 ft of net oil sand. Vertical closure of the oil-saturated sandstone is 650 ft. Areal extent is 102 ac.

The reservoir sandstones are turbidites that have been correlated with Upper Miocene Puente Formation. The depositional environment is middle to outer fan with predominantly distal turbidite facies. The Terminal 7 fault block is located on the crest of the Wilmington anticline and is bounded by two east dipping normal faults. Terminal zone deposition occurred early in the development of the Wilmington anticline and before the onset of major faulting.

The Terminal 7 sands can be cataloged into three major sand-rich fan sequences. Each of the 11 sands studied has a different oil-water contact and is considered a separate flow unit. The Terminal sands are unconsolidated lithic arenites. The sandstones are sheet sands with a sandstone/shale ratio ranging from 4:1 at the base to 11:1 in the uppermost sand unit. Shale breaks on wireline open hole logs are described in cores as thin to medium-bedded silty shales or laminated siltstones.

The porosity estimates for the Terminal 7 reservoir rocks are derived from a borehole gravity survey. Core derived permeabilities were used in reservoir calculations. The Upper Terminal sands have the best reservoir properties in the Wilmington field, which is reflected in an average permeability variation factor of 0.32.

Volumetrics were calculated for each flow unit using Zycor software. The following computer generated maps were constructed for the upper and lower Terminal subzone: structure, net oil sand isochore, original water saturation, original oil in place, initial reserves, and development. The reservoir currently has one injection well and six production wells. With full development, an additional injection well and seven production wells could be completed.

AAPG Search and Discovery Article #91024©1989 AAPG Pacific Section, May 10-12, 1989, Palm Springs, California.