Microseismic monitoring of borehole fluid injections: Data modeling and inversion for hydraulic properties of rocks

Attention paid to microseismic monitoring during geothermal or hydrocarbon reservoir operations has grown considerably over the last several years. The observation of microseismicity occurring during borehole fluid injections or extractions has a large potential in characterizing reservoirs at locations as far as several kilometers from boreholes (Talwani and Acree, 1985; Adushkin et al., 2000; Fehler et al., 2001). The most common application has been hydraulic fracture imaging and growth characterization (e.g., Phillips et al., 1997; Urbancic et al., 1999). Longer-term microseismic monitoring has been used to map oil-producing natural fractures (e.g., Rutledge et al., 1998); it also shows promise in tracking flood fronts in the case of enhanced oil recovery (e.g., Maxwell et al., 1998). Beyond delineating conductive fracture geometry and inferring fluid-flow paths, microseismic data could potentially be used to measure in-situ hydraulic properties of rocks at interwell scales, providing information that could further guide operations to optimize field production.