基于相场法的裂缝性地层压裂裂缝延伸特征研究  

Hydraulic fracture extension characteristics of fractured formation based on phase field method

作　　者：易良平 张丹 杨若愚 肖佳林[4] 李小刚[2] 杨兆中[2] YI Liangping;ZHANG Dan;YANG Ruoyu;XIAO Jialin;LI Xiaogang;YANG Zhaozhong(School of Mechatronic Engineering,Southwest Petroleum University,Chengdu,Sichuan 610500,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,Sichuan 610500,China;Exploration Division of PetroChina Southwest Oil and Gasfield Company,Chengdu,Sichuan 610041,China;Institute of Engineering and Technology,Sinopec Jianghan Oilfield Company,Wuhan,Hubei 430035,China)

机构地区：[1]西南石油大学机电工程学院,四川成都610500 [2]西南石油大学油气藏地质与开发国家重点实验室,四川成都610500 [3]中国石油西南油气田勘探事业部,四川成都610041 [4]中国石化江汉油田分公司工程技术研究院,湖北武汉430035

出　　处：《油气藏评价与开发》2022年第4期604-616,共13页Petroleum Reservoir Evaluation and Development

基　　金：四川省科技计划项目“页岩压裂的损伤力学特征研究”(2020JDJQ0059)。

摘　　要：基于相场法理论建立了多孔弹性地层中压裂裂缝延伸模型,在该模型中,流体流动遵循达西定律,岩石的渗透率各向异性,且是岩石最大主应变的函数。通过3个不同时间步长算例验证了模型的收敛性,并基于建立的模型,研究了原地应力差、相交角、注入速率和压裂液黏度对水力裂缝与天然裂缝相交后延伸轨迹的影响。研究表明:①水力裂缝只能开启天然裂缝的一翼;②相交角和原地应力差越小,水力裂缝越容易开启天然裂缝;③提高注入速率有利于完全开启天然裂缝,因此,压裂施工过程中,在井口装备和地下管柱强度允许的条件下应尽量提高施工排量;④注入压力随注入速率和流体黏度的增加而增加。最后通过将研究模型模拟结果和前人物理模拟实验结果进行对比,验证了模型的可靠性。Based on the theory of phase field method,a model of fracture propagation in porous elastic formation is established.In the proposed model,the fluid flow in the porous rock obeys Darcy’s seepage law,and the permeability of rock is anisotropic and a function of the maximum principal strain.The convergence of the model is verified by comparing the results of three different time steps cases.Meanwhile,based on the proposed model,the effects of the in-situ stress difference,intersection angle,injection rate,and fracturing fluid viscosity on the intersection behaviour of hydraulic and natural fractures are investigated.The results indicate that:①The hydraulic fracturing can solely make one side of the natural fracture open;②The smaller the intersection angle and in-situ stress difference,the easier the hydraulic fracture is to open the natural fracture;③Increasing injection rate is beneficial to completely open the natural fractures,therefore,in the process of fracturing construction,the construction displacement should be increased as much as possible under the conditions of wellhead equipment and underground string strength;④The injection pressure increases with the increase of injection rate and fluid viscosity.Finally,the reliability of this model is verified by comparing the simulation results of this model with those of previous laboratory experiments.

关 键 词：相场法 水力压裂 裂缝延伸 天然裂缝 多孔介质 

分 类 号：TE357[石油与天然气工程—油气田开发工程]