Monitoring the Hydraulic Stimulation and Production of an Unconventional Reservoir Using 4D 3C Seismic

In order to determine optimal well spacing, depletion radii, and vertical extent of the stimulated rock volume in an unconventional shale gas reservoir in the Western Canadian Sedimentary Basin, an advanced multicomponent, time-lapse survey was shot by Talisman Energy in 2008 along with microseismic (surface, water well, and downhole) surveys and a multicomponent VSP. Four seismic surveys were conducted before, during and after hydraulic fracturing of multiple horizontal wells. The purpose of the time-lapse data is to determine if unconventional production and hydraulic fracturing can be delineated using multicomponent seismic methods. Time-lapse work is relatively novel in the unconventional realm, and large amplitude/time changes of the magnitude seen in offshore conventional and many heavy oil reservoirs are not expected. This emphasizes the need for maintenance of quality control measures through the cross-equalization process. Preliminary results on the cross-equalized PP surveys indicate amplitude/time changes coincident with wellbore trajectory. Though clear evidence of time-lapse changes exists, work to understand these results continues.