Feasibility of Sector Modeling Approach in a Giant Petroleum Field

Abstract

The decision analysis process to develop a petroleum field can be very complex. This process contemplates a set of tasks, which include the study of various representative scenarios, and different production strategies that aid decision-making. However, when it comes to giant reservoirs, the computational requirements of the respective simulation models may be too high. High computational cost may demand simplification that may yield suboptimal solutions so it is desirable to find simplifications that preserve the quality of the solutions. One approach to reduce the simulation requirements is to divide the reservoir into sectors, and to use sector models isolated in the decision making process. This study evaluates the feasibility of using a model of an isolated sector from a giant reservoir in the management of this sector. The observed decrease in the simulation time of the isolated model makes this methodology attractive. However, it is necessary to evaluate in advance the impacts of its use on the flow behavior of this sector when inserted in the Full Field model. The case study presented is a deterministic realization of a reservoir with analogous characteristics to the Mero pre-salt field, with high communication along the reservoir. The global differences found between the isolated model and the Full Field model presented a range that justifies the use of the isolated model in the development process of this sector, without losing significant accuracy in the results. A methodology is proposed to evaluate the differences between both models using field and well indicators. Discussions about the impact of local differences between the two models are presented. The causes of these differences were investigated and attributed to three main factors: the production strategy; changing of boundary conditions; and rock properties of the model.