Evaluation of Steam-Injection Designs for the Duri Steamflood Project

Abstract The Duri Steamflood (DSF) Project is the largest thermal enhanced oil recovery (EOR) project in the world, surpassing in production both Kern River and Belridge in the San Joaquin Valley of California. The field is located in Riau Province on the island of Sumatra, in Indonesia. Duri is the second largest field in the country, producing nearly 200,000 BOPD of steamflood production. The field is being operated and developed by P.T. Caltex Pacific Indonesia (CPI), a production sharing contractor to Pertamina. The DSF Project will develop about 15,000 acres of reservoir utilizing over 4000 producing wells. At present, only about 1/3 of the field is under active steamflood. The DSF Project is divided into twelve development units called Areas. New Areas are about 1400 acres in size and are developed, that is drilled and put on injection, every 1 3/4 to two years. The steamflood development involves the use of symmetric patterns of varying size and configuration. Inverted seven spots, approximately 11 5/8 acres in size, have been the *References and figures at end of paper principal pattern configuration for Area development thus far, including the Area currently being drilled [1]*. For future Areas, inverted five and nine spots, approximately 15 1/2 acres in size, are planned. This change will be implemented as a result of detailed reservoir simulation studies conducted in CPI [2]. Pattern producer completions are either cased hole gravel packs (CHGP) or, more commonly, open hole gravel packs (OHGP). Most OHGP wells have 10 3/4" casing set at the top of the drive zone, hole opened to 14", and packed with 20-40 US mesh gravel outside of 6 5/8" screen liners. Up to four distinct sand intervals and 250 ft of pay are simultaneously completed and flooded in a single pattern. The main challenges in downhole design and completion of DSF's steam injection wells have arisen from the relatively large pattern sizes and the need to distribute high rates of steam to multiple intervals of varying permeability. Several different, multi-point, downhole injection systems have been used in Duri. The design, field testing, and evaluation of these various systems are here presented and discussed.