Kenneth M. Mallon¹, Jory Pacht², Jay Magness³

(1) Petroleum Geology Consultant, Houston, TX
(2) Seis-Strat Services, Inc, Houston, TX
(3) Magness Petroleum Company, Long Beach, CA

ABSTRACT: Identification of Undeveloped Reserves of the Ford Zone Sands in the Wilmington Townlot Unit, (WTU) Wilmington Field, Los Angeles County, California

The WTU comprises the northwest portion of the Wilmington Field (third largest US oilfield). The Ford is the deepest of six main producing intervals. It has produced slightly more than 7MMBO (approximately 10.5% of Ford OOIP) in the WTU. However, primary Ford recovery in an adjoining unit was 18.4%. Expected primary and secondary recovery in the nearby THUMS unit is more than 30%. This suggests that more than 15 million additional BO can be produced from the Ford.

The Ford consists of interbedded, thin, deep-water sands, silts and shales. Individual sands are generally less than ten feet thick, average 23% to 30% porosity, and show 75 to 350 md permeability. The Ford was divided into eleven subzones. Complex, channel-like packages of sands exhibit coarsening-upward or blocky SP signatures. Net sand isochore mapping shows subzones are elongate and trend north to northeast. Two fault sets are present. Primary faults strike generally north-south. A secondary fault set, with minor vertical separation, trends northeast. Structural and stratigraphic compartmentalization hindered success of the initial reserve development.

Most Ford wells in the WTU were drilled more than 40 years ago. No modern technology was applied - in contrast to other areas of Wilmington Field. Subzone perforation and completion, water flooding, fracture stimulation, and redrilling of wells to enhance production have not been done. There has been no evaluation of low-resistivity sands and no reservoir characterization study until now. Considerable oil remains to be produced by a comprehensive modern development program.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado