Influência da qualidade do vapor na injeção contínua de vapor em reservatórios de óleo pesado

Abstract

As the worldwide light oil reserves have decreased, the industry goes after new means of recovering heavy oil that corresponds for about 70% of the hidrocarbonate reserves in the world. The extraction of this type of oil, which is more complex and expensive than the light oil extraction, suffers from the lower relative price of the barrel, given that the refinement of heavy oils generates products of less value added. It is then needed higher investments and new technology, or the betterment of know techniques to explore these kind of fields. The steam injection is a known and utilized technique. This mechanism heats the reservoir, which lowers the oil viscosity leading to an increase in the recovery factor. The objective of this work is to study the influence of the independent variables, flowrate and steam quality, and verify their influence upon some dependent variable, like recovery factor, oil rate, cumulative oil, and also the influence upon the reservoir's inner energy and losses to adjacent layers. Nowadays there are several injection methods that aim on a higher recovery factor, resulting in most cases in high cost. The injection of water in the form of steam is of great applicability given its low cost and better efficiency than other injection methods. The results show the influence of the steam injection on the cumulative oil, oil rate and energy delivered to the reservoir. The numerical simulations were accomplished on the STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) module of the CMG (Computer Modelling Group) software, version 2012.1. For this work were used semi-synthetic models with fluid and reservoir data that can be extrapolated for practical situations on the Brazilian Northeast, on the Potiguar Basin. The results show the influence of steam quality in the recovery factor and in the oil rate.