Uncertainty Quantification Enhancement by Combining Data of Varying Accuracy and Precision

A common issue in Depth conversion and Volumetrics calculation is the estimation of the range of variation of important reservoir parameters, like structural closure depth or reservoir volumes, which are often poorly estimated. For example, the GRV and hydrocarbon volumes in most of the developed reservoirs are found to be closer to the P90 than to the P50 determined at the exploration phase, which means that the range of variation is underestimated.

Combining data sources of varying precision and accuracy such as seismic data, CCAL, SCAL or logs, which correspond to different scales, is a difficult issue. It requires appropriate mathematical tools, like the ones provided by Geostatistics. This paper details the geostatistical techniques than can be used for calculating geological models and quantifying the associated uncertainty. Focus is put on the role played by input data accuracy and precision in the final estimation of GRV and hydrocarbon volumes range of variation, accounting for the varying accuracy and precision that are manageable in practice. This allows decision makers to take the most appropriate decisions concerning the field development. The methodologies and results are illustrated with a simplified modelling based on a real dataset, emphasis being put on structural modelling.