ABSTRACT
A case history is presented of a tertiary, steamflood pilot project conducted from 1982–1989 in the Tar Zone reservoir of the Fault Block II Unit located in Wilmington Field, Los Angeles County, California. The design, implementation, performance and operations of the pilot are reviewed. Prior production mechanisms consisted of pressure depletion by solution gas drive followed by pressure maintenance using waterflooding. The 20 acre pilot area contained four, inverted 5 acre five-spot patterns. The reservoir steamflooded was the "D1" member, an unconsolidated sandstone, with 60 feet average thickness at a depth of about 2,550 feet. The nine production wells were completed open-hole with gravel-packed, wire-wrapped screens and were initially steam stimulated. The four injection wells were also completed open-hole with wire-wrapped screens. Using individual natural gas-fired, steam generators, high quality steam was continuously injected down insulated tubing into each injector.
During its seven year history, the steamflood pilot recovered 1.1 million barrels of oil from the injection of 7.2 million barrels ewe (cold water equivalent) of steam. The pilot project demonstrated successful field operations and an oil recovery factor of 75% (of the oil-in-place at the start of project) in this waterflooded, medium depth reservoir.
The pilot has been expanded to over 150 acres totalling 54 new production wells and 39 new steam injection wells treating both "T" and "D1" members of the Tar Zone in Fault Block II Unit.
