低渗透储层缝内暂堵多分支缝压裂技术研究
Multi-branch fracturing technique of low permeability reservoirs by temporary plugging within fractures
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摘要: 压裂增产改造是实现大庆低渗透储层开发建产的主要手段。大庆油田低渗透储层的大规模压裂虽然取得了较好的效果,但施工成本高,难以实现效益开采。为提高外围低渗透储层增产改造效果,采用纤维缝内暂堵多分支缝压裂技术来提高人工裂缝泄油面积。通过室内实验评价了纤维性能、明确了分支裂缝形成条件;结合数值模拟及现场施工需求,确定了缝内转向时机与工艺施工时间,优化了缝内裂缝转向条数与缝长,确定了纤维缝内暂堵多分支缝优化设计方法。纤维缝内暂堵多分支缝压裂技术可在保证改造效果的同时有效控制施工成本,实现低渗透储层的经济有效开采,已在大庆外围低渗透储层成功应用18口井,取得了较好的改造效果。Abstract: Fracturing stimulation is a major means to effectively develop and produce Daqing low permeability reservoirs. Although large–scale fracturing has better results in Daqing oilfield, the construction cost is high priced and it is difficult to achieve efficiency exploit. To improve the low permeability reservoir production effect, using fiber temporary plugging in multi–branch fractures is a good method which can improve the artificial fracture oil drainage area. Through laboratory experiments, the properties of the fibers were evaluated and the conditions for the formation of branch cracks were clarified. Combined with numerical simulation and field construction requirements, the good transferring timing of within fractures and the construction time were made clear, the number and length of transferred fractures were optimized, and then the design method of multi–branch fracturing technique of low permeability reservoirs by fiber temporary plugging within fractures was determined. The fracturing technique not only insured the modification effect but also effectively control the construction cost and relized economic and effective exploitation of low permeability reservoir, which was successfully applied in 18 wells of Daqing peripheral low permeability reservoirs and achieved a good effect.