2018 Volume 83 Issue 1 Pages 40-50
This paper attempts to review effective methodology for evaluating geologic risks in the distributions and properties of petroleum system-related sediments, mainly focusing on reservoir/source rocks and migration carrier beds. Since geologic uncertainty may differ depending on the data conditions in the prospect area or targeted basin, appropriate sedimentologic and geologic methodology for predicting the distributions and properties should be selected for better risk assessment in each data condition case. In case the data are sparse or spatially limited in and around the prospect area, it can be effective to apply the methods examining the relative position witin the basin, sediment supply systems, and depositional systems, with practical use of present analogues, the source-to-sink theory, and numerical modeling. If three-dimensional sesimic survey data are available, then effective information can directly be obtained for risk assessment. In case the data are dense in the prospect area, the integrated evaluation of geophysical data, deterministic modeling and geostatistical modeling can be applicable for high-quality and quantitative risk assessment.In this case, deterministic geologic and sedimentologic data should be used as geologic constraints in the geostatistical modeling.
Even in the sparse data case, it can be suggested that multiple combination of distribution/peroperty analysis methods provides key information for geologic uncertainty reduction and accurate risk assessment. Improvement of data density and quality can be another key point for precise risk assessment.
