考虑任意压力分布的裂缝诱导应力场计算模型及其应用

发布时间：2018-10-08 08:17

【摘要】：通过复分析和断裂力学Westergaard应力函数方法建立局部受均匀内压力作用下的诱导应力分布模型,并以此为基本单元结合数值积分复化矩形法的思路,叠加得到考虑任意压力分布情况的诱导应力计算模型。采用先计算再虚实分离的方法进行编程,验证单元模型的精度。模拟缝内压降、裂缝不对称延伸和净压力周期性波动对裂缝诱导应力的影响。结果表明:经典的裂缝诱导应力模型仅是局部受均匀内压力模型的特解;考虑缝内压降后,远井位置形成缝网的可能性大幅度下降,天然裂缝的稳定性显著提高;裂缝不对称延伸使裂缝附近的压应力区向短半缝偏移,但远离裂缝区域的诱导应力仍关于裂缝中垂线对称;缝内净压力周期性波动对诱导应力的影响范围在五分之一半缝长以内,求解远离裂缝区域的应力时,可以将平均压力直接带入经典公式计算。
[Abstract]:Through complex analysis and Westergaard stress function method of fracture mechanics, the induced stress distribution model under uniform internal pressure is established. The induced stress calculation model considering arbitrary pressure distribution is obtained by superposition. The accuracy of the unit model is verified by the method of calculating first and separating the real and the real. The effects of pressure drop, asymmetrical extension of fracture and periodic fluctuation of net pressure on the induced stress are simulated. The results show that the classical fracture-induced stress model is only the special solution of the local uniform internal pressure model, and the possibility of formation of fracture pattern in the far well position is greatly reduced after considering the pressure drop in the fracture, and the stability of natural fractures is improved significantly. The unsymmetrical extension of the fracture causes the compressive stress zone near the fracture to shift to the short half crack, but the induced stress far away from the fracture area is still symmetrical about the vertical line in the fracture. The influence range of periodic fluctuation of net pressure on induced stress is less than half of the crack length. When the stress far away from fracture region is solved, the average pressure can be directly introduced into the classical formula.
【作者单位】：西南石油大学油气藏地质及开发工程国家重点实验室;
【基金】：国家自然科学基金重大项目(51490653) 国家“973”重点基础研究发展计划(2013CB228004)
【分类号】：TE319

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