不同水力加载条件下非均质储层缝网扩展规律研究
发布时间：2018-08-08 10:51
【摘要】：水力压裂可显著提高页岩气等致密储层岩体的渗透性以增加油气产量,然而受多因素影响,水力压裂形成缝网结构的机理和压裂优化设计一直是研究的焦点和难点。本研究基于渗流-应力-破坏耦合计算模拟方法,对不同水力加载条件下的非均质储层水力压裂过程进行了模拟和对比研究。研究结果表明:水力压裂过程中起始注水压力和增量大小对水力压裂缝网扩展和改造区域形态有着显著的影响。当起始注水压力小于等于模型材料体抗拉强度,并缓慢增压致裂时,压裂过程可近似视为稳态应力-破坏-渗流耦合作用过程的不同阶段,这种情况下仅在压裂井孔周围形成两组对称式的伞状水力裂缝带。当对模型体施加高于模型材料体破裂压力的注水压力时,相当于对压裂孔快速施加高动水压力,水力裂缝沿压裂孔全方位迅速萌生并快速扩展,当注水压力值高于破裂压力一定幅值时,压裂改造可形成围绕压裂井全方位的放射状裂缝网络,使压裂储层得以最大范围改造。在拟静力和拟动力两种加载条件下,不同水岩相互作用机理是造成不同水力加载条件出现不同缝网结构的力学机制,而对于实际的页岩气储层改造,压裂产生围绕压裂井全方位放射状的缝网结构则是一种最优的体积压裂改造。
[Abstract]:Hydraulic fracturing can significantly improve the permeability of tight rock mass, such as shale gas, in order to increase oil and gas production. However, due to the influence of many factors, the mechanism of hydraulic fracturing forming fracture network structure and the optimum design of fracturing have been the focus and difficulty of the research. Based on the coupled seepage stress-failure simulation method, the hydraulic fracturing process of heterogeneous reservoir under different hydraulic loading conditions was simulated and compared. The results show that the initial injection pressure and increment have a significant effect on the extension and reconstruction of hydraulic fracturing network in the process of hydraulic fracturing. When the initial injection pressure is less than or equal to the tensile strength of the model material and the fracture is caused by a slow increase of pressure, the fracturing process can be approximately regarded as the different stages of the steady state stress-failure seepage coupling process. In this case, only two sets of symmetrical umbrella hydraulic fracture zones are formed around the fracturing well hole. When the water injection pressure of the model body is higher than the fracture pressure of the model material body, it is equivalent to applying high dynamic water pressure to the fracturing hole quickly, and the hydraulic fracture is springing up and expanding rapidly along the fracturing hole. When the value of water injection pressure is higher than a certain amplitude of fracture pressure, the radial fracture network around the fracturing well can be formed by fracturing reconstruction, and the maximum range of fracturing reservoir can be reconstructed. Under two loading conditions, pseudostatic and pseudo-dynamic, different water-rock interaction mechanism is the mechanical mechanism which results in different fracture network structure under different hydraulic loading conditions, but for the actual shale gas reservoir transformation, Fracturing is a kind of optimal volume fracturing.
【作者单位】： 中国科学院地质与地球物理研究所中国科学院页岩气与地质工程重点实验室;中国科学院大学;
【基金】：中国科学院战略性先导科技专项(B类)(XDB10030602) 国家自然科学基金项目(41372325,41372323,41402280)资助
【分类号】：TE357.1
，
本文编号：2171564
[Abstract]:Hydraulic fracturing can significantly improve the permeability of tight rock mass, such as shale gas, in order to increase oil and gas production. However, due to the influence of many factors, the mechanism of hydraulic fracturing forming fracture network structure and the optimum design of fracturing have been the focus and difficulty of the research. Based on the coupled seepage stress-failure simulation method, the hydraulic fracturing process of heterogeneous reservoir under different hydraulic loading conditions was simulated and compared. The results show that the initial injection pressure and increment have a significant effect on the extension and reconstruction of hydraulic fracturing network in the process of hydraulic fracturing. When the initial injection pressure is less than or equal to the tensile strength of the model material and the fracture is caused by a slow increase of pressure, the fracturing process can be approximately regarded as the different stages of the steady state stress-failure seepage coupling process. In this case, only two sets of symmetrical umbrella hydraulic fracture zones are formed around the fracturing well hole. When the water injection pressure of the model body is higher than the fracture pressure of the model material body, it is equivalent to applying high dynamic water pressure to the fracturing hole quickly, and the hydraulic fracture is springing up and expanding rapidly along the fracturing hole. When the value of water injection pressure is higher than a certain amplitude of fracture pressure, the radial fracture network around the fracturing well can be formed by fracturing reconstruction, and the maximum range of fracturing reservoir can be reconstructed. Under two loading conditions, pseudostatic and pseudo-dynamic, different water-rock interaction mechanism is the mechanical mechanism which results in different fracture network structure under different hydraulic loading conditions, but for the actual shale gas reservoir transformation, Fracturing is a kind of optimal volume fracturing.
【作者单位】： 中国科学院地质与地球物理研究所中国科学院页岩气与地质工程重点实验室;中国科学院大学;
【基金】：中国科学院战略性先导科技专项(B类)(XDB10030602) 国家自然科学基金项目(41372325,41372323,41402280)资助
【分类号】：TE357.1
，
本文编号：2171564
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