Abstract

A three-dimensional numerical model was used to evaluate various methods to optimize steamflood performance of a typical California heavy oil reservoir. Results show that, for confined patterns, a reduction in steam (heat) injection rate after steam breakthrough is preferable over a constant injection schedule. A linear heat reduction schedule resulted in the highest discounted net or saleable oil production with less steam injection. On the other hand, rate reduction is not beneficial for unconfined patterns because steam migrates and drains oil from outside the pattern boundaries.

Hot waterflood following steamflood may result in higher incremental recovery compared to injector shut in. However, the incremental recovery for both is small, and the higher recovery by hot waterflood may be offset by the water injection and increased water handling costs. A recompletion of the producer after steam breakthrough resulted in increased recovery.