A Bayesian Approach for Resolving OWC and GOC from 4D Seismic Data

4D seismic technology has proven successful in monitoring the post-production fluid contacts in several reservoirs. Most of these cases include thick reservoirs with reasonably good vertical connectivity in which fluid contacts are shown as isolated events on the seismic data. However, challenges still remain when the contacts’ displacements are around or below seismic tuning thickness. Time-lapse wedge modelling and Sim2seis proved to be useful in providing an insight into the problem, however, it is not an easy task to link the modelling results to the observed 4D response. Here, by application of engineering driven simplifying assumptions on the geometry of the contacts and saturation profile within each fluid zone a Bayesian approach is proposed to invert the 4D seismic data to post-production contacts. As wells as the best case scenario, this method provides the uncertainty associated with the contacts’ locations. This approach could be used to quantify the location and thickness of the displaced oil rim for effective management and development of the field.