Numerical Modeling and Laboratory Experiments on a Propagating Hydraulic Fracture Intersecting with a Preexisting Fracture

Abstract

Hydraulic stimulation in a geothermal reservoir occurs both by creating new hydraulic fractures and stimulating pre-existing natural fractures. Therefore, investigating how pre-existing fractures and newly created fractures interact during hydraulic stimulation is necessary to better understand the creation of a fracture network. To study this problem, we 3D printed core samples containing a pre-existing interface and an initial hydraulic fracture and then applied axial stress and confining pressure using a triaxial system. The experimental results were compared to the analytical work on the cross/terminate criteria for orthogonally intersecting fractures expanding on Renshaw and Pollard (1995). In our experiments, a hydraulic fracture was initiated and propagated to an orthogonal pre-cut. The propagating hydraulic fracture crossed the pre-cut with higher axial stress but terminated with lower axial stress, in agreement with the analytical work. With this work, we also suggested the possibilities of using 3D printed core samples for more complex fracturing experiments. This demonstrates the utility of 3D printed core samples for studying fracture network creation, and raises the possibility of modeling more complex fracture networks in future laboratory experiments.