CASEY, BRIAN J.
Occidental of Elk Hills, Inc., Tupman, CA

Abstract: Occidental View of the Elk Hills Field, California

Occidental Petroleum acquired operatorship of the Elk Hills Field, southern San Joaquin basin, in February 1998. Commercial production of the field began in 1919 from the Pliocene SOZ and IDGZ reservoirs. The Pliocene layers lie at depths above 4000 feet within a broad anticlinal fold. They are compartmentalized by listric normal faults that sole out into the Mio-Pliocene Reef Ridge Shale. The Upper Miocene Stevens interval was discovered in 1941. It is currently produced from three, reverse fault bounded and tightly folded anticlines above 12,000 feet.

The Stevens pools produce gas and 35<deg> API gravity oil from deep marine sandstones and bio-siliceous shales. The SOZ produces mostly 25<deg> API gravity oil from shallow-marine sandstones. The IDGZ produces dry gas from marginal-marine to fluvial sandstones.

Although horizontal wells were drilled previously in the field, their dip-orientation yielded no more pay than a vertical well. Both conventional and intermediate-radius horizontal wells are now being drilled parallel to strike to increase the net pay and completion interval, and to target specific productive horizons.

Currently, reservoir development depends on well data, but dramatic improvements could be achieved if quality seismic data were available. A seismic testing program was initiated in 1998 to identify favorable acquisition and processing parameters. A two-phase, 3D seismic campaign is now planned with acquisition beginning in late 1998.

As development proceeds the full integration of geological, reservoir and production data becomes progressively more important. Evaluation of this data using 3D visualization tools is an integral part of future development planning.

AAPG Search and Discovery Article #90920©1999 AAPG Pacific Section Meeting, Monterey, California