Going for the last drop

One of the most ambitious secondary recovery operations ever attempted is now being constructed by Abu Dhabi Marine Areas Ltd. for its offshore reservoirs in the Arabian Gulf. Abu Dhabi Marine Areas Ltd., an international consortium of British, French, Japanese, and Middle Eastern interests, decided last year to prevent production of excessive gas and halt declining production by installing a system for high-pressure seawater injection. Initially, the reservoir's existing 40 producing wells will be supported by 4 water-injection complexes, each with up to 7 boreholes. When the project is complete, there may be up to 48 more production wells in the reservoir with 83 injection bores, giving an output of 700,000 bpd of oil and needing 1,400,000 bpd of water (the difference between the quantities is due to presence of gas in the oil). The second, somewhat smaller ADMA reservoir, which has so far shown no signs of deterioration, is also to have a waterflooding scheme installed consisting of 2 injection complexes. Production of 500,000 bpd is planned, requiring the injection of 1,000,000 bpd of water. Total cost of the project is expected to be in the region of $1.1 billion.