Print this page3-D Seismic Survey in the Long Beach Unit, Wilmington Oil Field, California
OTOTT, GEORGE E., STEVEN R. ROTH, JAMES PICKARD, and JORY A. PACHT
In January 1995 a state-of-the-art 3-D seismic survey was shot in the 30-year-old Long Beach Unit of the giant Wilmington Oil Field located in southern California. The Long Beach Unit has produced more than 800 million barrels of oil. Approximately 150 million barrels of recoverable reserves remain. Production occurs from about 50 individual sand packages within a Miocene/Pliocene deep water turbidite system. The highly faulted anticline has a complex reservoir geometry that is only partially understood despite over 1300 wells in the 6700 acre field.
The 3-D seismic survey was shot to delineate reservoir layering and compartmentalization. These data will be integrated with existing geologic, engineering, and petrophysical data to plan producer and in-zone injector locations. The seismic data will also be used to delineate fault traps in deeper zones, map the basement surface, and identify upside potential in unexplored areas of the Unit. Preliminary analysis of the 3-D data has resulted in revised fault interpretations and discovery of new faults that have affected new-well placement. in addition, our work suggests that Miocene through Lower Pliocene strata were deposited longitudinally from northwest to southeast along the basin axis. In contrast, Upper Pliocene strata were sourced from the northeast and deposited in submarine fans oriented perpendicular to the basin axis.