Costs for off-shore extended reach wells can be substantial. To decide if and where to drill, the uncertainties in the reservoir geometry (e.g. top reservoir), rock parameters (e.g. porosity, permeability), saturations (e.g. free water level, saturation height) and dynamic parameters (e.g. relative permeabilities, viscosities) have to be taken into account.
Extensive reservoir characterization under uncertainty was performed and the geometrical and rock parameters were captured by generating thousands of realizations. These realizations were clustered in Multi-Dimensional Space using a dynamic response. As dynamic response, the oil production of "dummy" wells was chosen. The resulting 100 cluster centroids were transferred to dynamic simulation.
Next, the saturation and dynamic parameter ranges were introduced. Latin Hypercube sampling and Differential Evolution lead to an ensemble of history matched models that was used for forecasting of incremental oil production from an extended reach well compared with a base case.
For decision analysis, the workflow comprised generating of various development options (e.g. horizontal, slanted, multi-lateral well). Then, the incremental cumulative oil production of the various development options compared with the base case was calculated. Next, the incremental Net Present Value of the most promising development options was determined.
The selection of the development option was based on the Expected Utility and ensuring that the Probability of Economic Success hurdle was met.
To evaluate the potential to further increase the project value, a distance based Generalized Sensitivity Analysis of parameters on the project economics was performed. The results showed that no further measurement could be conducted in the field to reduce the parameter range, the selected development option has an Expected Monetary Value of 51.16 mn $, an Expected Utility of 49.42 mn $ and the Probability of Economic Success is 81.1 %.