Pore Pressure Mapping Using Microseismicity and Borehole Data

The data describing the stress field normally includes either direct in-situ measurements in the wellbore, or indirect data – focal mechanisms of microearthquakes in the area of interest. Joint inversion of the source mechanisms and various types of borehole data allows recovering of both principal stress directions and magnitudes. A combination of data from reservoir injections and focal mechanisms from induced microseismicity allow reconstruction of the full stress tensor: stress orientation and principal stress magnitudes. Ultimately, the full stress tensor together with the focal mechanisms provide an estimate of pore pressure at the location of every event, which can be mapped in time and space. We successfully apply joint stress inversion to a Barnett shale hydraulic fracturing dataset and demonstrate pore pressure mapping.