Abstract

Surface seismic data is usually processed in isolation from either log or borehole seismic data. As a result, there is often an inconsistency between these data sets. To improve the quality of the surface seismic data, VSP guided reprocessing is performed on an interactive workstation. This paper presents the method of residual reprocessing of surface seismic data and application of the technique to Real Data from offshore South-East-Asia.

In example 1, a weighted average phase rotation of 46 degrees has been applied to the seismic data to reconcile the surface seismic with logs and VSP data at the well location. The gas/oil contact that was barely visible on the original seismic is better defined in the reprocessed seismic data. Also, the oil/water contact is enhanced and its lateral continuity better defined.

In example 2, residual reprocessing using a 60 degree phase rotation is applied to the data to restore zero phase prior to 2- D seismic inversion processing. The validity of the results predicted by the inversion is proved by the agreement obtained away from the reference well, between the seismic derived acoustic impedance traces and acoustic impedance logs from two additional wells.