Avaliação do modelo semi-analítico de poços de petróleo na simulação composicional de reservatórios de petróleo em conjunto com malhas não-estruturadas

Abstract

One of the most complex activities performed by petroleum reservoir simulation is to model the fluid flow along wells. Numerical evaluation of wells is not feasible, due to the high level of mesh refinement needed to correctly account for every characteristic of the fluid flow. Analytical models were initially conceived to approach the wells separately from the rest of the reservoir, therefore presenting multiple restrictions. The growing use of unconventional well configurations, such as deviated, horizontal or ramified wells, created the need to develop new methods capable of correctly calculate the production variables for these configurations. Therefore, semi-analytical formulations that do not incorporate most of the assumptions related to the traditional analytical models were developed in order to make reservoir simulators more robust and capable of dealing with more realistic reservoirs and well configurations. The present work aims to analyze a semi-analytical well model, in conjunction with the EbFVM (Elementbased Finite-Volume Method) methodology for unstructured meshes in a compositional petroleum simulator. The analysis was done by comparing the results obtained with the method in study and those obtained with a benchmark analytical model. The results are expressed in oil and gas production curves and showed a good match between the models, when most of the restrictions imposed by the analytical model are observed. At the same time, the results showed a deviation of the semi-analytical model curves in comparison to the analytical model curves for conditions that do not observe the simplifying hypotheses in the well flow, such as linear or unsteady flow.