Objective Assessment of the Reliability of 4D Seismic for Value of Information Analysis

In Value of Information (VOI) analyses seismic reliability is often obtained by expert assessments. These carry an inevitable subjectivity that is perceived as a significant weakness of VOI methodology. An alternative objective approach is presented for the case of 4D surveys. Reservoir property grids are converted to elastic parameters and the seismic response is simulated for different time intervals, producing several seismic cubes. Selected attributes representing essentially the seismic effect and the production effect are then classified in a two-way table from which the probabilities of observing a real and a false 4D anomaly (true and false positives) are computed. This method allows a comparative evaluation of the potential value of seismic acquisition surveys and contributes to the selection of the best option.