Hydraulic fracture simulation based on hydro-mechanical coupled element partition method

Abstract

Element partition method (EPM) is a fracture simulation method. It takes advantage of geometry feature of triangular element to derive the stiffness matrix of a cracked element. Once a fracture runs across a triangular element, this element will be transformed into a cracked element. The contact and friction between crack faces are automatically incorporated into the numerical model. By this means, any number of fractures can be embedded into a prescribed background mesh without introduction of any extra degree of freedom. It avoids the setup of joint element and remeshing issues in fracture simulation. Hence, the EPM presents great advantage in dealing with the massive fractures. To simulate the hydraulic fracture more effectively, a fully hydro-mechanical coupled equation is established for the cracked element. It can account for the interactions between the mechanical field and the hydraulic field in a cracked element. The KGD verification suggests that this method is validated in hydraulic fracture simulation. It can effectively simulate the multiple hydraulic fracture propagation and coalescence. It provides a simple and efficient simulation method for hydraulic fracturing in the complex reservoir.