Time-lapse seismic surveying: a multi-disciplinary tool for reservoir management on Snorre

Abstract

Today reservoir monitoring is being used for increased oil recovery in about 75% of the fields operated by Statoil. The Snorre Field is a good example of how time-lapse seismic surveys help understanding and drive reservoir management. Even after more than 14 years of time-lapse seismic surveys, interpreting the 4D results is challenging due to the complexity of the reservoir and the drainage strategy. The time interval between seismic surveys is much larger than the water and gas injection cycles, and these variations in production operations between surveys make it difficult to reconstruct the reservoir history, including the inversion of the time-lapse data to estimate pressure and saturation changes. Using time-lapse seismic surveying as a tool to improve the static and dynamic models is important, but understanding the meaning of the 4D signal together with the uncertainties is critical. Here we describe how the asset works with the 4D data and show how time-lapse seismic data are used qualitatively.