Microseismic shearing generated by fringe cracks and bedding-plane slip

Abstract

Summary Natural joint structures in layered rock provide an analog for interpreting patterns of hydraulic-fracture microseismicity often observed in unconventional gas reservoir. We interpret systematic patterns of source locations and mechanisms in terms of fringe cracks and bedding-plane slip as the hydraulic fracture encounters layer interfaces. In this sense the microseismicity provides a direct picture of tensile fracture growth through a reservoir, highlighting the deformation at and near bedding boundaries as the hydraulic fracture rips through or along layer interfaces. Understanding these processes is important in imaging the reservoir accessed and drained by injection stimulation.