| Block leng41 is a typical deep thick massive block reservoir, which is one of the most important edge and bottom extra-super heavy oil reservoirs in Lengjia Oilfield. Since 1995, the block developed by two series of strata in inverted nine-spot pattern with well spacing 100m. After 13 years, the reservoir stepped into later stage of cyclic steam simulation. There are two major problems which block the reservoir development, one is low reservoir pressure which makes the deliverability low, and the other is bottom water breakthrough which makes the reserve losing. In order to realize the long-term continuous development and find an effective way to deep heavy oil development mode conversion, the study carried out to SAGD reservoir design to enhance oil recovery by geological scrutiny and successful experiences in and abroad.During the research course, basis on the geological scrutiny and residual oil results, SAGD reservoir deign is optimized which combines vertical well with horizontal well by the reservoir dynamic analysis, testing materials analysis, reservoir engineering, reservoir simulation, comparative analysis for the similar reservoirs and economic evaluation. By this development mode, it broke the normal develop mode and creates the higher oil production rate and the ultimate recovery. According to the research, four pilot test SAGD well groups were deployed. The pilot test area is 0.098km2, reservoir thickness above the well is 88m and the OOIP is 90.8×104t. By this mode, the SAGD well groups produce 8 years, and the 28.7×104t oil may produced. During the course, the peak oil production rate reaches to 47.2t/d, average oil production rate is 33t/d, enhanced oil recovery by 31.6% and the OSR is 0.16. The researches provide guidance and references to similar reservoirs. And at the same time, it has an important effect on development mode conversion for mid-deep heavy oil reservoir in Liaohe oilfield.
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