ABSTRACT: Reservoir Scale Sandbody Architecture of Pliocene Turbidite Sequences: Long Beach Unit, Wilmington Oil Field, California

LOWRY, PHILIP, ARCO Oil and Gas, Plano, TX, CRETIES D. JENKINS, ARCO Oil and Gas, Bakersfield, CA, and DANIEL J. PHELPS, University of Kentucky, Lexington, KY

ARCO has recently increased its working interest in the Long Beach Unit and is implementing a waterflood redevelopment program with the City of Long Beach and THUMS. As part of this work, a major reservoir description project was initiated to help optimize the waterflood design. Part of the description work involved correlation of more than 1000 well logs (average well spacing, 10-20 acres) over a 500-600 ft productive interval. The correlation work was assisted by a proprietary software package that enables rapid zonation and three-dimensional visualization of the reservoir.

The most prolific producing interval of the unit (cumulative production, 350 MMB), the Upper Ranger zone (Pliocene Pico Formation), is dominated by a series of thick (100-200 ft) laterally offset, lobate sandbodies. Several of these sandbodies extend over the entire area of the field (12 sq. miles) and are separated by shales up to 30 ft thick. The smallest of the Upper Ranger sandbodies (the Du-F1 interval) measures about 1 mi along depositional dip and 2 mi along depositional strike. Some of these sandbodies are composed of a series of thinner (40-60 ft thick), laterally offset, lobate sandbodies separated by laterally persistent (1-2 sq. miles) shales up to 10 ft thick.

In addition to the zonation of the reservoir, this work provides data on the dimensions, volumes, and continuity of key reservoir elements. This type of data may be used as input data to geologic modeling software packages for fields for which well data are much more sparse.

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)