孔洞三维裂纹应力强度因子分析

针对裂缝性低渗透油田孔洞三维裂纹在Ⅰ型加载下应力强度因子求解方法的多样性,研究了以权函数理论为基础的三维裂纹应力强度因子的求解方法。通过对由权函数法推导的应力强度因子曲线与Newman曲线进行比对,结果吻合较好,说明用权函数理论计算三维裂纹应力强度因子具有较高精度,且计算简便。综合运用应力三维度断裂准则、线弹性断裂力学和流体力学理论,分析了孔洞三维裂纹的起裂和三维扩展问题。通过算例分析了缝长、缝高、缝宽随施工时间变化的延伸规律。结果表明,该方法和计算模型是有效的、可行的。

Reserce on the Well Three-Dimensional Cracks Stress Intensity Factor

With an aim at the solution multiplicity of the well three-dimensional cracks sress intensity factor under the load,the solution method of three-dimensional cracks stress intensity factor based on weight function theory is studied.By comparing the result curve with Newman result curve,the results are found to be well fitted,whereby indicating that weight function is considerably accurate and simple in calculating stress intensity factor.The stress tri-axicity fracture criterion,elastic fracture mechanics and fluid mechanics theory are comprehensively adopted to analyze the problems of the initial growth of the well three-dimentional cracks and three-dimentional extension.Also,this paper analyzes the extending rules of crack length,crack altitude and crack width with the variation in constructing time via the calculation examples.The results indicate that this method and the computation model are reliable and suitable.