针对缝间应力干扰造成的段内各裂缝非均匀延伸问题,建立综合考虑应力干扰、流固耦合、多裂缝流量分配的分段多簇压裂裂缝动态延伸数值模型.基于建立的数值模型,研究了射孔孔眼摩阻、射孔簇间距、储集层岩石弹性模量、压裂液黏度对多条水力裂缝延伸形态的影响.模拟结果表明,考虑射孔孔眼摩阻时裂缝发育较为均衡;随着簇间距缩小、岩石弹性模量或压裂液黏度增大,应力干扰增大,导致部分裂缝缝宽变窄而减少进液,加剧了段内各裂缝的非均匀延伸.合理的孔眼摩阻能够有效促进多裂缝均匀延伸,为此提出了简便的射孔孔眼摩阻优化计算方法.通过估算压裂过程中缝间诱导应力值,定量计算出维持压裂段内裂缝均匀延伸所需的孔眼摩擦系数,并以此优选合理的射孔工程参数.采用射孔摩阻优化方法对1口水平井射孔参数进行计算,数值模拟结果及现场压裂效果显示,优化后的射孔参数能够有效维持各裂缝均衡发育.%Aiming at analyzing the issues of non-uniform growths of multiple hydraulic fractures caused by stress shadowing,a numerical model considering elasto-hydrodynamic,stress interference and flow distribution into different fractures was built.Based on the model,the effects of perforation friction,perforation cluster spacing,Young modulus of rock and fracturing fluid viscosity on the growth of multiple fractures were investigated.The simulation results show that the growths of hydraulic fractures are relatively uniform with adequate perforation friction;the reduction of perforation cluster spacing,increase of Young modulus or fluid viscosity will cause the reduction of some fracture width and uneven flow distribution into these fractures,thus aggravating non-uniform growth of multiple fractures.Since appropriate perforation friction is conducive to the uniform growth of fractures,a convenient quantitative optimization method to calculate the needed perforation friction for uniform growth was proposed.By estimating interfracture induced stress during fracturing,the perforation friction coefficient needed to maintain uniform growth of fractures inside a stage is calculated,and reasonable engineering parameters of perforation can be selected based on this.The perforation parameters of a horizontal well were calculated with the proposed method,and the simulation results and actual fracturing performance show that the optimized perforation parameters can effectively keep uniform growth of fractures.
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