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介绍应力阴影的概念及其理论模型,结合颗粒流流固耦合计算原理构建模型,模拟并分析单一水力裂缝周围因应力阴影效应产生的诱导应力的分布情况,分析表明应力阴影主要表现为最小水平主应力的增大,且其对水力裂缝压裂效益具有两面性。利用建立的数值模型,进一步分析在不同初始水平主应力下,应力阴影效应对水力裂缝扩展方向的影响,结果表明:初始水平主应力比越大,应力阴影效应产生的诱导压力越大,不利于新裂缝的开裂及发育;当初始裂缝内液压接近或大于最大初始水平主应力时,注水孔压裂水力裂缝的扩展方向将发生转向,有利于复杂裂缝网络的形成。
The concept of stress shadow and its theoretical model are introduced. According to the fluid-structure interaction theory of particle flow, a model is constructed to simulate and analyze the distribution of induced stress caused by the stress shadow effect around a single hydraulic fracture. The analysis shows that the stress shadow mainly shows as the minimum level Stress increases, and its hydraulic fracturing benefits have two sides. The numerical model is used to further analyze the effect of the stress shadow effect on the direction of hydraulic crack propagation under the different primary horizontal principal stress. The results show that the larger the initial horizontal principal stress ratio is, the larger the induced pressure generated by the stress shadow effect is not conducive to When the hydraulic pressure in the initial fracture is close to or greater than the maximum initial principal stress, the expansion direction of the hydraulic fracture in the water injection hole fractures will be turned to favor the formation of a complex fracture network.