A Novel Method of 4D Analysis and its Application to Land Seismic Data

An alternative to traditional 4D seismic repeatability metrics is proposed. The new metric is based on surface consistent, iterative least-squares analysis of pre-stack seismic data in common source and receiver domains. It is simultaneously estimated across multiple time-lapse seismic surveys. Two sets of scalars are produced, one that is common to all surveys, and one that changes with each survey. The second set of scalars contains information on 4D repeatability. The new repeatability analysis method is applied to data acquired for a seismic monitoring experiment in a carbonate oil field in Saudi Arabia. The results indicate that buried hydrophones are less repeatable than the colocated geophones. These conclusions and the new metric are confirmed using post-stack normalised root mean square (NRMS) repeatability analysis on data recorded using high source density 2D swath line acquisition into the same permanent receivers.