Aspects of rock physics in 4-D seismology

In recent years, time-lapse 3-13 or 4-D seismology has been used to identify bypassed oil, to monitor steam and CO[sub 2] injection processes, and even to track the movement of the injected water. However, the feasibility of applying seismic technology to monitoring oil recovery processes and the ability to interpret the seismic results depend to a large extent on the understanding of the physics or seismic properties of the reservoir rocks and fluids. We have carried out several laboratory rock physics investigations on seismic properties of reservoir rocks in relation to oil recovery processes. Particularly, we found that seismic properties were dramatically affected by he injected steam in heavy oil sands, by the injected CO[sub 2] in carbonate rocks, and in some cases, by the injected water in light oil reservoir sands. In this paper, we present laboratory results of seismic properties of oil lands from several places in the world, including Indonesia, Canada, and of West Texas carbonates undergoing CO[sub 2] injection. We discuss the effects of reservoir geology, fluid properties, and recovery process on the seismic properties and how the laboratory results can be used in the feasibility studies and seismic interpretations. We also show examples of 4-Dmore » and cross-well seismic results from the Duri field, Indonesia, and from a West Texas carbonate field undergoing CO[sub 2] flooding.« less