Spatially limited tomographic inversion for time-lapse oil reservoir monitoring

Abstract

In this paper, we develop an improved technique for using seismic travel time tomography for time-lapse reservoir fluid monitoring. A model of a real reservoir is used to simulate the tomographic response to fluid injection for enhanced oil recovery (EOR). In order to evaluate the applicability of seismic tomography to fluid-injection EOR monitoring, a numerical experiment was carried out. As ordinary tomography inversion failed to obtain good results, an inversion technique was developed under the assumption that ?a velocity change occurs mainly in the reservoir? during the EOR process. A velocity estimation method for direct imaging of the injected fluid front was also developed. The results of this estimation improve the applicability of seismic tomography for monitoring of fluid-injection EOR.