Print this pageRisk and Uncertainty 
Analysis
in Known Hydrocarbon Systems: A Fit-for-Purpose Approach
W.C. Riese1, W.A. Hill1, T. Koleszar2, R.M. MacDonald1, G. McMaster1,
R. Rudser2, H.M. Sebastian1, and L. Tomberlin1
1 BP America Production Co, Houston, TX
2 BP Canada, Calgary, AB
Exploration in known hydrocarbon systems requires an analysis of risk and uncertainty which focuses on prospect-specific attributes. This analysis may not require critical review of all hydrocarbon system components, the presence or effectiveness of some having already been demonstrated in the area.
Our approach focuses first on parallel empirical, mapping-based evaluation and statistical comparison with similar known accumulations and plays. These allow definition of the uncertainty ranges surrounding reservoir thickness, extent, and yield; and gross hydrocarbon volumes.
Second, we focus on analysis of the risk elements which determine the probability of finding any hydrocarbons in the prospect: source access; reservoir presence and effectiveness; trap presence; seal effectiveness; and the relative timing of migration, trap formation, and trap preservation.
Third, we determine the economic requirements necessary to justify exploratory and casing-point-forward investments: are the volumes sufficiently large, and the residual
economic risks sufficiently small to proceed?
Finally, a decision-tree is built which captures the economic risks and attendant volumes. This allows full characterization of the expected risk-weighted economic outcome for the investments.
This approach has allowed us to achieve an 83% program success rate, and to discover more than 100% of expected predrill volumes.