针对现有页岩气体积压裂层理裂缝扩展模型及其计算方法研究的不足，基于三点弯曲试验，结合数字图像法获取了页岩层理关键力学参数；利用弹性力学理论和线弹簧模型建立了页岩气体积压裂层理裂缝扩展拟三维数学模型，并得到了试验验证；开发了裂缝几何参数计算程序，计算分析了层理参数与压裂施工参数对水力裂缝扩展的影响规律。结果表明：当层理刚度小于10 GPa/m 及大于30 GPa/m 时，剪切滑移量达到极大值及极小值，且基本保持不变，当层理刚度在 10～30 GPa/m之间时，层理刚度与剪切滑移量呈线性负相关关系；当层理密度为 5～7条时，主裂缝会沟通更多的层理；当层理强度为 5～8 MPa时，水力裂缝易穿层扩展，且能使层理产生剪切滑移，从而生成复杂裂缝；当压裂液排量和压裂液黏度分别在 9～12 m3/ min和 2.5～5 mPa·s 范围内时，水力裂缝易穿层扩展，最终形成十字型裂缝，有助于复杂裂缝的形成。该研究对认识页岩层理力学性能及其对层理裂缝扩展规律的影响有一定的指导意义。In view of the inadequacy of existing research onthe bedding fracture propagation model of shale gas volume fracturing and its calculationmethod

the mechanical characteristic parameters of shale bedding were obtainedby three-point bending (TPB)test combined with digital image method. A pseudo-three-dimensional (P3D)mathematical model of hydraulic fracture propagation in shale gas volumefracturing was established by the utilization of elastic mechanics and linespring model

which was verified by laboratory experiments. A calculationprogram for geometric parameters of shale bedding fractures was developed tocalculated and analyzed the influence of bedding parameters and fracturing engineeringparameters on the distribution of hydraulic fracture. The results show that theamount of shear slip reaches a maximum value and a minimum value when thebedding stiffness is less than 10 GPa/mand greater than 30 GPa/m

and keeps basically unchanged. And the beddingstiffness is linearly negatively correlated with the shear slip when thebedding stiffness is in the range of 10–30GPa/m. The main fracture will communicate with more beddings when the beddingdensity is in the range of 5–7. Thehydraulic fracture is easy to penetrate the bedding and can lead to the beddingshear slip when the bedding strength is in the range of 5–8 MPa

therebygenerating a complex fracture network. Moreover

the hydraulic fracture is alsoinclined to pass through the bedding when the pumping rate and viscosity of fracturingfluid are in the range of 9–12 m3/minand 2.5–5 mPa·s

respectively

and finally a cross-shaped fracture is formed

which isconducive to the formation of complex fractures. This study has a certainguiding significance for understanding the mechanical properties of shale andits influence on the propagation regulation of hydraulic fracture.