Quantitative Analysis of Seismic Uncertainty

Uncertainty is inherent in E&P business and understanding uncertainty enables mitigation of E&P risks. Therefore, quantification of uncertainty is essential in decision-making and managing uncertainty generates business value. One of the most critical parameters for reserves uncertainty and well placement is positioning of interpreted geological structure in the depth domain. Even with our best efforts to combine all available data there is still ambiguity in our models, caused by the inherent non-uniqueness of the seismic experiment. The result is uncertainty in the true positions of events in our images. These uncertainties can lead to exploration risk (e.g. trap failure), drilling risk (e.g. dry wells), and volumetric uncertainties. Whilst the underlying ambiguity can never be fully eradicated, a quantified measure of these uncertainties provides deeper understanding of the risks and leads to more informed decision making. We introduced a workflow for the statistical analysis of structural uncertainty associated with the ambiguity of tomographic velocity model building. Our method provides a quantitative way to determine the trap risk. Here we present this seismic-driven uncertainty analysis method and a case study for its application in the Gulf of Mexico.