Abstract

The Benakat field in P.T. STANVAC INDONESIA's South Sumatra producing acreage has produced over 130 million barels of oil since its discovery in 1932. The field produces from three separate reservoirs called the First, the Second and the Stray sands in the Talang Akar formation. The main producing mechanism during the early stages of the field was solution gas drive augmented by a weak flank water drive.

Pressure maintenance by gas injection into the crestal wells was conducted from 1935 to 1962, while a peripheral waterflood was initiated in 1966 and expanded in 1969.

This paper reviews and anlyzes the performance of the Benakat First Sand after gas injection and waterflooding. The paper reviews the production history, the effect of the gas injection program and the subsequent secondary recovery activities by waterflooding. A performance review and estimated incremental recovery by waterflooding are presented.

The paper concludes that the combination of early gas injection and subsequent waterflooding have been an important factor in the estimated ultimate recovery of over 70 percent of original oil in place in the First Sand of the Benakat field.