【摘要】 文章结合中原油田油藏渗透率低、自然递减率高的实际特点,研究了低渗透油藏的重复压裂技术。通过重复压裂前的评价可知该区的候选井具有重复压裂增产的能量和物质基础;据压前地层评价、水力裂缝的诊断技术,提出了重复压裂选井选层的原则;运用压力恢复试井和水力裂缝模拟等方法分析了初次裂缝失效的原因,得到了重复压裂需解决的主要矛盾就是提高裂缝的导流能力,并据此提出了提高重复压裂效果所采取的高砂比和强制闭合及分压选压等重复压裂的技术;根据所确定的技术和以往压裂用支撑剂评价结果及中原油田的油藏特征,利用实验研究选择了适合油藏特点的重复压裂材料体系;重复压裂技术现场试验10口井,施工成功率达100%,有效率90%,取得了较好的复压增产效果。更多还原

【Abstract】 The multiple fracturing techniques of low permeability oil reservoir were investigated in consideration of the characteristics of low permeability and high natural decline rate of the oil reservoirs in Zhongyuan Oil Field. According to the prefrac formation evaluation and the diagnostic techniques of hydraulic fractures, the principles of the well-selection and horizon-selection for multiple fracturing were put forward and the selected well should be possessed of the stimulation potential and material base by multiple fracturing. The reasons for incipient fracture failure were analyzed by use of the methods as pressure build-up test and hydraulic fracture simulation, etc., and it was concluded that the principal contradiction needing to be settled for the multiple fracturing is to enhance the flow conductivity of fractures, so that some multiple fracturing techniques as high sand ratio, forced closure, separate zone fracturing, selective fracturing and so on were proposed in order to improve multiple fracturing effectiveness. In light of these techniques and in consideration of the evaluation results of the proppants used for fracturing in the past and the characteristics of the oil reservoirs in Zhongyuan Oil Field, the suitable material system of the multiple fracturing was selected through experimental research. 10 wells were used for testing these techniques. The results indicated that the job success ratio was up to 100% and the effective ratio 90%, thus achieving a good stimulation effectiveness.更多还原