5D Interpolation, PSTM and AVO Inversion for Land Seismic Data

To address the issue of inadequate sampling, typical of land seismic data, an AVO processing flow should include interpolation and prestack migration prior to the AVO inversion. It is well established that seismic data should be prestack time migrated prior to AVO yet the irregular sampling inherent in land data can introduce migration artifacts which distort the estimates of the AVO inversion. By performing 5D minimum weighted norm interpolation prior to the PSTM, the wavefield is better sampled leading to better migration and AVO results. By working in five dimensions, the algorithm can interpolate through gaps that are problematic for lower dimensional interpolators. The 5D interpolation is amplitude preserving and appears to improve the signal-to-noise ratio with minimal evidence of smearing. In order to support these assertions, a series of parallel processing test flows were performed and compared on a 3D seismic survey from Alberta, Canada with extensive well control. For each of these flows, Ostrander gathers at key wells, AVO attributes, and their ties to 29 wells were examined. The interpolation PSTM flow prior to AVO inversion produced the best correlation to the well control.