Numerical Study of Interaction Between Hydraulic Fracture and Discrete Fracture Network

Abstract

This paper discusses the interaction between hydraulic fracturing and the pre-existing discrete fracture network (DFN) in a rock mass subject to in-situ stresses. Two-dimensional computational model studies have been used in an initial attempt towards understanding how reservoir response to fluid injection is affected by some of the DFN characteristics and to operational variables such as injection rate. • Opening of pre-existing fractures due to slip-induced dilation, which is referred to as hydroshearing or shear stimulation, and is permanent;

Numerical Analysis on the Optimization of Hydraulic Fracture Networks

“…The DFN model has been used by many researchers [3,7,8,20,32]. For example, Riahi and Damjanac [20] investigated the effects of NF connectivity, injection pressure, etc., on the complexity of hydraulic fracture network. Kresse et al [32] investigated the propagation of fracture networks when complex natural fractures are created.…”

“…As a result, these methods are ill-conditioned for the fluid-rock coupling system of hydraulic fracturing. Another problem is the complexity of grid re-meshing, which is necessary for the accurate simulation of fracture trajectory [20]. The second kind is meshless methods.…”

“…With the distributions of fracture length, orientation, aperture, etc., and the fracture density, random NF networks can be created [20]. The DFN model has been used by many researchers [3,7,8,20,32]. For example, Riahi and Damjanac [20] investigated the effects of NF connectivity, injection pressure, etc., on the complexity of hydraulic fracture network.…”

“…The Discrete Fracture Network (DFN) model is always used to reconstruct complex NF networks. With the distributions of fracture length, orientation, aperture, etc., and the fracture density, random NF networks can be created [20]. The DFN model has been used by many researchers [3,7,8,20,32].…”

“…These models can roughly be classified into three kinds. The first kind is the models which need grid meshing in the whole region, such as the finite difference method [14], finite element method [15], extended finite element method [16][17][18] and discrete element method [19,20], etc. There are many softwares based on these methods, such as UDEC/3DEC, PFC, RFPA, FLAC, etc.…”