Seismically guided reservoir description involves estimating and mapping reservoir properties such as lithology, porosity, and pore fluid. The estimates of reservoir properties are derived from seismic attributes that are obtained from prestack seismic inversion by means of some form of amplitude variation with offset (AVO) analysis and inversion. Seismic amplitude inversion relies on a stable and stationary seismic wavelet, preserved over offset, so that any variations in phase and amplitude behaviour can be related to changes in rock properties. It is, therefore, important that processing does not create false AVO anomalies or attenuate or distort genuine AVO behaviour. We look at Inversion QC, which is a new approach designed to monitor and guide data processing to provide some confidence that the final products from the processing phase are suitable inputs to seismic inversion for reservoir description. We recommend using Inversion QC on all data processing where Quantitative Interpretation (QI) is a follow-on process. Not only does it ensure the data is optimally processed for phase and amplitude stability for AVO, but also gives greater confidence in the reliability of inversion attributes and reduces the need of rectifying processing problems that are discovered during the subsequent inversion phase of a project.
