Abstract

A steamflood pilot was initiated September 1975 in Duri Field, Sumatra, Indonesia. This pilot has been very successful and recovered 19.8 MMSTB incremental oil above primary depletion through December 1985. The pilot originally consisted of 16 inverted 5-spot well patterns on a nominal 15.5 acre pattern size. The 5-spot patterns were converted to 9-spots after 6 years of steam injection. Duri crude oil has a 22° API gravity and a gas-saturated viscosity of 120 cp.

Oil production increased from 600 STB/d in 1974 to 9000 STB/d in 1984. Oil production has not declined due to improved production operations, infill wells, and production from an upper (non-steamflood) sand. Lifting efficiences were improved by gravel packing the production wells and lowering casing pressure. The cumulative fuel/oil ratio is 0.21, which indicates an efficient steamflood operation.

Wellhead flowline temperature were monitored to evaluate steamfront advancement. A wide variation occurred in the heating of the production wells. We conclude that the steamfront areal advance was highly nonuniform. Temperature observation well data also indicated gravity override and steam leakage to an upper sand.