Constrained AVO for CO₂ storage monitoring at Sleipner

A feasibility study of inverting for CO₂ elastic properties using a model based AVO inversion is carried out. We use principal component analysis on a set of PP reflection coefficients to calculate an optimal basis function for the AVO response of the CO₂ plume. The method is applied to the marine seismic data recorded on the CO₂ storage site at Sleipner to map the extent of CO₂ plume, and provide an estimate of the seismic contrast parameters. Appropriate elastic properties and their variabilities are derived from log data, advanced rock physics models, and error propagation analysis. The sensitivity tests show that it is difficult to discriminate between high CO₂ saturations. We finally obtain high-resolution images of impedance contrasts we aim to use as a priori constraints for high-resolution tomography after background trend convolution.