3-D seismic monitoring of an active steamflood

I present an idealized physical model of steamflood fluid-flow and make rock physics predictions of seismic impedance changes that might be observable in 3-D surface seismic monitoring data. Four distinct fluid-flow phases are considered. Closest to the steam injection well, a small hot steam zone should be very visible in seismic data due to a predicted 30% decrease in P-wave velocity (Vp) compared to pre-steam reservoir conditions. With increasing radial distance from the injector, an annulus of hot water is likely to be seismically transparent due to a weak (5%) decrease in Vp, but a larger radial annulus of hot oil may be visible due to a predicted 10–15% decrease in Vp. A high-pressure cold oil front is predicted to propagate away from the injector one order of magnitude faster than the thermal fronts. If the increased pore pressure due to steam injection forces the high-pressure cold oil to cross the bubble point, a large increase in Vp of at least 15% may be visible in seismic monitor data. This model is currently being tested on a 3-D field data set. Preliminary results are exciting and will be published later this year.