参数空间变异性对岩石水力压裂裂隙扩展形态的影响  

Effect of parameter spatial variability on fracture propagation morphology of rock hydraulic fracturing

作　　者：申林方[1] 华涛 王志良[1] 李松波 陈骞 SHEN Lin-fang;HUA Tao;WANG Zhi-liang;LI Song-bo;CHEN Qian(Faculty of Civil Engineering and Mechanics,Kunming University of Science and Technology,Kunming,Yunnan 650500,China)

机构地区：[1]昆明理工大学建筑工程学院,云南昆明650500

出　　处：《岩土力学》2025年第4期1294-1302,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.42167022,No.11962008,No.42067043)。

摘　　要：为了研究非均质岩石水力裂隙的扩展特征,采用中心点法随机场理论对岩石的物理力学参数进行随机化处理,同时实时追踪新生裂隙表面并施加压力模拟压裂液与裂隙壁面间的相互作用,基于键型近场动力学方法建立了模拟岩石水力压裂过程的数值计算模型。根据含预制裂隙岩石压缩破坏过程的试验结果,验证了计算模型的有效性,并探究了岩石弹性模量空间变异方向、波动范围及射孔间距等因素对岩石水力裂隙演化特征的影响。结果表明:当岩石弹性模量呈层状分布时,其水力裂隙倾向于沿着结构薄弱面扩展;而当参数分布无方向性时,水力裂隙的扩展表现出强随机性,裂隙网络趋于复杂化。当参数波动范围较小时,岩石弹性模量离散程度较高,在水力压裂作用下局部会产生应力集中,易于形成复杂的裂隙结构;而较大的参数波动范围会使岩石趋于均质化,水力裂隙分支呈单一化扩展,使得裂隙扩展率相对较低。双射孔作用下均质岩石裂隙扩展呈对称分布,射孔压力使得射孔之间区域的裂隙扩展受到抑制作用,导致主裂隙倾向于向两侧边界扩展;而双射孔作用下非均质岩石水力裂隙扩展出现竞争关系,在应力集中效应和材料非均质性的共同作用下使得一条水力裂隙优先扩展后抑制另外一条裂隙的发展。In order to study the fracture propagation morphology of hydraulic fracturing in heterogeneous rock,the random field theory of the center point method was applied to randomize the physical and mechanical parameters of rock.The surface of newly formed fractures was tracked in real time and pressure was applied to simulate the interaction between fracturing fluid and fracture wall.A numerical model for simulating the hydraulic fracturing process of rock was proposed based on the bond-based peridynamics.According to the compression test results of rock containing a prefabricated crack,the effectiveness of the proposed model was verified,the evolution of rock hydraulic fractures was explored considering the effect of the spatial variation direction of rock elastic modulus,fluctuation range of rock elastic modulus,and perforation spacing.When the distribution of rock elastic modulus is layered,the hydraulic fractures tend to propagate along the weak interfaces.When the parameter distribution is directionless,the expansion of hydraulic fractures exhibits strong randomness,and the fracture network tends to become more complex.When the parameter fluctuation range is small,the variability of rock elastic modulus is significant,which caused stress concentration locally,making it easy to form complex fracture structure.A larger parameter fluctuation range leads to homogenization of rock,and the expansion of hydraulic fractures is singular,resulting in a relatively low fracture propagation rate.Under the action of dual perforation,the expansion of fractures in homogeneous rock exhibits a symmetrical distribution.The perforation pressure suppresses the expansion of fractures between the perforations,leading to the main fractures tending to expand towards the boundaries on both sides.And there is a competitive relationship in the expansion of hydraulic fractures in heterogeneous rock.Under the combined effect of stress concentration and material heterogeneity,one hydraulic fracture preferentially expands and then inhibits the

关 键 词：水力压裂 岩石 随机场 键型近场动力学 裂隙追踪 

分 类 号：TU452[建筑科学—岩土工程]