4-D seismic steamflood monitoring

David E. Lumley

david@sep.stanford.edu

ABSTRACT

Six repeated 3-D seismic data sets are analyzed at a single steamflood site in Indonesia. Migrated $\mbox{3-D}$ images and velocity analysis illuminate fluid-flow features of the steamflood in time-lapse mode. The steam front is visible seismically as large reflection and diffraction responses, and velocity decreases of up to 40%, in a disk centered at the steam injection well. The steam front intensifies in place at a radius of less than 50 m for the first nine months of injection, and then breaks out and rapidly propagates to the northwest of the injection pattern at and beyond the 13-month survey. The steam movement mapped by time-lapse seismic correlates with two temperature observation wells and oil production data from the surrounding producing wells. A thin annulus of hot water (steam condensate) is visible in time slices and a 10% increase in velocity. A transient pressure front is observed at 2 months of steam injection to propagate towards the northwest, but not toward the southeast. Mapping the early pressure front movement predicts where the thermal and steam fronts will follow. The steam front is shown to follow the leading pressure front movement to the northwest one full year after the pressure front was initially mapped.