Utilization of the GRM (Geological Representative Models) to Integrate Different Types of Uncertainties in the Decision Making Process (SPE-120924)

摘要

Decision analysis applied to the development of petroleum fields must take into account the risk associated to several types of uncertainties. The combination of these uncertainties can be used to quantify the risk related to the decision process. The objective of this study was to evaluate the impact of the integration of different types of uncertainties, especially geological and economics on the complementary development project of an offshore field located 34 Km of Rio Grande do Norte coast in a water depth of 46 meters. It was applied a methodology, involving quantification of uncertainty and risk analysis (Costa, 2003), that proposes the use of models representing the geological uncertainties, called Geological Representative Models (GRM), to integrate with economic uncertainties (oil price, investment value, project start, etc.) and improved the decision making process of the project. In the risk methodology, many models are created and it is not viable to use all these models to integrate with other types of uncertainties. Therefore, some representative models are selected to continue the analysis. These models are selected based on the variation of net present value (NPV), oil production (Np), oil recovery (RF), water production (Wp), etc. The basic idea is to plot NPV (main objective function) against secondary objective-function (RF, Np, etc.) choosing models that are close to the values of P10, P50 and P90 that have significant variation in the other attributes. The adoption of this premise, which includes aspects of the amount and the speed of the recovery, is useful in sizing the later production facilities as well as in detailing the development plans and evaluating the flexibility of these plans. The adoption of this process as well as the use of an automated tool provided detailed information, contributing to the decision making process.