Feasibility study : pressure maintenance/secondary recovery of E-22 reservoir - Ardjuna Field, Offshore Northwest Java

Abstract This paper reviews black oil simulator studies used to formulate a reservoir management plan that would optimize ultimate oil recovery of the E-22 reservoir and would also be acceptable to various interested parties. The E-22 reservoir is located in the E structure, Ardjuna Field - Offshore Northwest Java. It is bounded on the east and west by well defined faults and by an igneous plug updip to the north. The reservoir consists of two sandstone layers separated by blanket shale. The layers apparently have a common gas cap but probably do not share a common aquifer. Since its start up in 1971, 53 million barrels of oil or 24% of the initial oil in place have been produced from this reservoir. Reservoir pressure has declined from 1090 psig initially to about 600 psig as of September 1982. Several model studies have been made since 1975 to monitor the performance of this reservoir. Predicted reservoir performance under 1) continued natural depletion, 2) gas injection, 3) water injection, and 4) simultaneous injection of gas and water, are examined. The studies conclude that gas injection into the gas cap will be the most efficient program both in view of recovery and cost. Water injection only and/or simultaneous injection of gas and water would be either less efficient or economically unattractive.