Hydraulic fracturing process by using a modified two-dimensional particle flow code-case study

Abstract

By using a modified PFC2D model, the authors conducted a series of simulations to examine the influences of in-situ stress ratio, fluid injection rate, anisotropy of laminated rocks, and perforation parameters on hydraulic fracturing process. The simulations indicated that: 1) larger in-situ stress ratio will induce smaller breakdown pressures and faster propagation, and hydraulic fractures will extend along the direction of the maximum principal stress or approach to this preferred path; 2) smaller difference of in-situ stresses or faster fluid injection rate is helpful for creation of complex fracture network; 3) weak layers are preferred locations and directions for fracture initiation and propagation in the laminated rocks; 4) hydraulic fractures initiate easily at the bottoms of perforation channels, and propagate generally along or approaching to the direction of maximum principal stress.