Experiment and Simulation Research on Hydraulic Fracture Propagation Characteristic under Interface Layer Influence

Abstract Key factor to develop shale reservoirs effectively is formed stimulated reservoir volume (SRV) of complex fracture network. When hydraulic fractures intersect with interface layer or natural fracture, fracture may slip along the interface, that provides a condition for the formation of fracture network. Bi material shale reservoir fracture mathematical is established in this paper, the critical conditions of shear sliding was studied by using elastic theory. Physics experiment is constructed by using the similarity criterion of the interface layer effect on hydraulic fracture extension, the influence of horizontal differential principal stress, interface friction coefficient and rock tensile strength on the fracture propagation is studied by hydraulic fracture experiment. This paper established finite model of bi material shale reservoir by using RFPA2D software, the influence of horizontal differential principal stress, interface friction coefficient and rock tensile strength on the fracture propagation is simulated. Analysis results show that: In the condition of low horizontal differential principal stress, low interface friction coefficient and high differential rock tensile, shearing slippage damage tend to happen, the fracture will continue extend along the direction of the maximum principal stress when it meted flaw after extend along the interface. On the contrary, fracture tend to cross the interface. This research has important theoretical value and practical significance to network hydraulic fracturing of shale reservoir.