重复压裂裂缝起裂角模型研究

Model study initiation angle of fracture under refracturing

艾池 赵万春 郭柏云 杨东梅

AI Chi ZHAO Wanchun GUO Boyun YANG Dongmei

大庆石油学院提高采收率重点实验室，黑龙江大庆　163318 路易斯安纳大学，美国路易斯安纳州　44690

Key Laboratory of Enhanced Oil Recovery, Daqing Petroleum Institute, Daqing 163318, China Louisiana University, Louisiana State 44690, U.S.

考虑流固耦合下重复压裂井周围注/采孔隙压力分布，建立重复压裂井周围孔隙压力诱导最大主应力和主应力方位角数学模型；考虑初次人工裂缝内充满弱可压缩流体，引入流体影响因子，建立初次人工裂缝诱导应力场模型；根据线性叠加?理，建立重复压裂井周围应力场分布模型；根据裂纹破裂准则，建立了重复压裂裂缝起裂角数学模型，得出重复压裂裂缝起裂角范围，并通过两口重复压裂井计算结果与生产结果进行对比，表明模型计算结果准确，且计算方法实用。

Considering the pore pressure of injection/production around the refracturing well under coupling liquid/solid, mathematical models are established to describe the maximum principal stress and orientation angle of maximum principal stress induced by pore pressure around refracturing wells. Considering that the initial artificial fracture is full of incompetent and compressible fluid, affection efficient of fluid is presented; the model of stress field induced by initial artificial fracture is established. According to the linear superimposition law, model of stress field distribution around refracturing well is established. According to the breakdown formula of the crack, model of initial angle of refracturing is set up. The refracturing initial angle variation range is obtained. Both the calculation and the production results of two refracturing wells are compared, which shows that the calculation of the refracturing initial angle is accurate, and the method is practical.