The impact of a multi-realisation processing approach on the 4D interpretability

Abstract

Summary Managing uncertainty in 4D quantitative interpretation is important for processes such as calibrating the production data and 4D seismic, pressure-saturation inversion, sim2seis analysis, and closing the loop by Seismic History Matching (SHM). During seismic data processing, there are many possible routes that can be taken and even more variations of the parameters within a set sequence. Decisions on which sequences and parameters to use are subjective and there are many possible “final” images. We then often use this image for quantitative interpretation with no concept of the uncertainty in that image. Multiple realisations of the post-stack volumes with alternative pre-stack processing workflows were generated and inverted for change in saturation estimation and compared to change in saturation predicted from the simulation model. The results show there is no single observed seismic realisation that we can rely on for 4D seismic interpretation, especially when processing parameters are subjective. Changing the parameters within the 4D processing yields changes not only on the 4D difference, time shift, flood front and contact movement as qualitative interpretation but also quantitatively for the change in saturation estimation.