Geomechanics-Based Stochastic Analysis of Microseismicity for Analysis of Fractured Reservoir Stimulation

Abstract

ABSTRACT: Natural fractures are the primary pathways for fluid migration and production in unconventional petroleum and geothermal reservoirs. In unconventional reservoirs, reactivation (and possible propagation) of natural fractures is an important component of stimulation. Slip on these fractures induced Microearthquakes (MEQs) and the locations of MEQ events reveal aspects of stimulation. In this paper, we discuss a technique for extracting information about the orientation of natural fractures from MEQs. This is achieved by combining geomechanics and geostatistics to better constrain uncertainties in natural fracture properties. We develop a new Geomechanics-Based Stochastic Analysis of Microseismicity (GBSAM) to provide quantitative estimate of natural fractures orientations. In this work, MEQs are generated using a poroelastic forward model for injection into a natural fracture network. A technique is then used to compare the analytical distribution of MEQs with the field observation. Several case studies are presented to illustrate the technique. This proposed method provides an effective way for interpreting MEQs for better characterizing the reservoir stimulation.