Fracture instability of sedimentary rock due to fluid injection

Abstract

This study aims to investigate characteristics of slip failure of shale fractures due to fluid injection. Shale was objectively chosen because it is a prominent target for subsurface fluid injection since it is a source of oil and natural gases. The MTS Model 815 Triaxial Rock Mechanics Test System is used to simulate actual subsurface conditions of high porewater pressure, temperature, and confining pressure, among others, and the sample is tested to failure to determine its shear strength. The results of the experiments are juxtaposed with the Mohr Circle Failure Criterion, a well-studied model on the responses of brittle, isotropic materials to normal and shear stresses. A better understanding of the failure mechanism and slip characteristics of shale will aid in the detection, mitigation, and responses to anthropogenic seismicity due to fluid injection in future.