LAUSR

Sequential multi-well cyclic steam stimulation (CSS) performs better than conventional CSS in heavy oil reservoirs. It distributes all wells into two or more groups. Each group injects steam simultaneously while different groups inject one by one. This paper further studies the effect of heterogeneity on well grouping in sequential multi-well CSS and explains how it improves conventional CSS. Results indicate that the channelling wells should be put into a same group and injected simultaneously. This can expand heating area, increase moveable oil and replenish reservoir energy. After appropriate well grouping, injecting group by group can establish a pressure drop between injecting and producing groups. The pressure drop and oil displacement directions change periodically. These mechanisms improve the performance of sequential multi-well CSS in heavy oil reservoirs on both technical and economic sides. [Received: March 25, 2016; Accepted: July 24, 2016]