Challenges in multi-segment prospect assessment: correlations and risk dependencies

Subsurface prospects (fluid traps, storage sites or locations of preferential locations of mineralization) are often composed of multiple reservoirs, structural or stratigraphic compartments. Standard tools for true probabilistic prospect assessment of such multi-segment prospects lack usability and transparency. Risk dependencies and volume correlations between segments (cross-segment correlations) and within segments (intra-segment correlations), can be quickly contradictory. Conflict are adjusted, if at all, using obscure rules which are difficult for the user to follow. The calculations are often referred to as “black box”, and the impact of the user choices are not easy to assess.

We present a transparent method for multi-segment prospect assessments integrating data, risk and uncertainty in a time efficient way for fast and robust decision making. In a fully probabilistic assessment, prospect risk and resources are calculated for carbon storage, oil and gas, and other resources such as natural hydrogen.