Passive seismic source imaging

Passive seismic source imaging has the unique potential to provide direct measurements of subsurface permeability [e.g. Shapiro et al. (1999)]. Fluid flow causes fracturing; you image the fracturing; therefore, you are imaging the fluid flow. This, along with the growth of (both surface and borehole) time-lapse seismic, has led to the drive towards the ``electric oilfield'' permanently instrumented and continually monitoring itself Jack and Thomsen (1999).

To date, however, most of the published case studies of microseismic fracture imaging rely on earthquake-style hypocentral event triangulation. For example, Maxwell et al. (1998) describe the successful application of such technology to the Ekofisk field in the North Sea. These approaches require automated event picking algorithms, and may run into problems if microseismic events are not localized in time.