Flow Mechanism and Application of Fishbone Well in Bohai Bay Heavy Oil Fields
Bohai Bay heavy oilfields are characterized by low productivity and low recovery factor. According to above character, a section of SZ 36-1 oilfield in Bohai Bay of Eastern China is chosen as a pilot area to test technologies of improving both well productivity and ultimate recovery factor. Based on the existing inverted nine-spot pattern, five fishbone wells were drilled in the stably distributed and relatively thicker pay zones and put into production along with the existing directional wells. In this paper, we study the mechanism of the heavy oil flow from porous medium to fishbone well. First, based on the analysis of mathematical characterization of horizontal segment and branch, the production model of the symmetrical and unsymmetrical fishbone well is established using the principle of potential superposition and infinitesimal congruence, accounting for the interference between branches. Using the above fishbone well model, the design of fishbone well is optimized including the well pattern, the length of horizontal segment, the length and number of branches, the distance between horizontal segment and branch. Five fishbone wells were successfully drilled and put into production in SZ36-1 heavy oilfield. The product rates ofthefishbone wells are as high as 90~ 150m<3>/d, which is 6~8 times of that a directional well. Reservoir simulation results show that the pilot areas ultimate recovery efficiency increment would reach as much as 4％. The implementation of these five fishbone wells in pilot area made a successful example to develop heavy oilfields. The fishbone wells project has been applied to other heavy oilfields in Bohai Bay. Twenty-eight fishbone wells have been put into production. According to the development effect, it could enhance not only the production, but also the ultimate recovery factor. The development pattern of combining the direction well with the fishbone well is an efficient way to develop heavy oilfields.
B. LI Y.C. ZHANG Q.P. LIU C.M. ZHAO L.S. CHEN
China Petroleum University (Beijing), Beijing China Technical Department of CNOOC Ltd.Tianjin, Tianj Technical Department of CNOOC Ltd.-Tianjin, Tianjin,China Technical Department of CNOOC Ltd.-Tianjin, Tianjin, China China Petroleum University (Beijing), Beijing, China
国际会议
首届世界重油大会(The Technical Sessions of the First World Heavy Oil Conference)
北京
英文
298-306
2006-11-12（万方平台首次上网日期，不代表论文的发表时间）