Time Lapse Processing for Reservoir Characterization

Time Lapse seismic is now becoming a commonly used tool for optimised hydrocarbon field management. Previously, seismic differences were sufficient to be the benchmark to evaluate the 4D signature. Today seismic differences are merely another attribute towards assessing the effect of reservoir production. 4D differencing technology is a highly specific and is based on a full set of generic and specific tools which include surface-consistent matching, 4D stratigraphic inversion, 4D AVO, 4D depth imaging and 4D multi-component processing. The backbone of this technology involves the progressive pre-stack equalization of two or more datasets of different vintages in order to remove the acquisition effects and reveal production-induced differences. Variation of elastic and acoustic parameters, and Poisson Ratio, are typical information that the geoscientists would have better knowledge after having performed the 4D study. The advantage of this methodology is such that even in highly unfavorable conditions of different data vintages, a useful 4D signal can still be extracted. In this paper, we present three case studies coming from different geological and economical environment.