Enhanced downhole microseismic processing using matched filtering analysis (MFA)

P assive-seismic methods provide an effective surveillance technology for monitoring the growth and activation of fracture networks during hydraulic-fracture (HF) stimulation of unconventional reservoirs, since microseismic events occur as localized brittle-failure processes that accompany tensile fracture growth (Warpinski, 2009; Maxwell, 2010). A number of acquisition geometries are used for microseismic monitoring (e.g., Eisner et al., 2010), including downhole geophone arrays installed in a deep wellbore close to the injection zone as well as deployment of surface and/or near-surface arrays. Downhole acquisition within a single monitor well is a commonly used configuration; although it is subject to a number of limitations that stem from limited observational apertures (Eaton and Forouhideh, 2011), this approach provides some distinct advantages by virtue of proximity of the sensors to the treatment zone (Maxwell et al., 2010). This paper introduces a novel correlation-based method for detection, location and analysis of microseismic events, tailored for a downhole recording geometry.