CO2 Capture and Storage in Mature Oil Reservoir: Physical Description, EOR and Economic Valuation of a Case of a Brazilian Mature Field

Abstract

Abstract The mitigation of environmental problems requires both national and international agreements, since they have possible global effects. In nationwide conventions (such as Rio, 92; Kyoto Protocol, 1997), a common conclusion has been the need to reduce greenhouse emissions, especially those due to CO2 from burning fossil fuels. For example, Kyoto protocol has established that industrialized nations should reduce their emissions over 2008-2012 by at least 5.2% compared with the 1990 levels. An alternative USA proposal is based on reducing greenhouse emissions by capturing and stockpiling CO2 in natural sites like oceans, caverns, depleted oil reservoir, etc. This paper presents a physical description and an economic analysis of a project to capture and inject CO2 in oil production and its storage in the depleted oil reservoir located in a mature field in Brazil. The Stella® Software has been used in order to analyze de dynamics of the whole process of CO2 sequestration in enhanced oil recovery, considering each step of the process with its respective energy requirements. The main findings of this have the following benefits: i) reduction in the emission of CO2; ii) extension of the operational life of the reservoir; and iii) improvement and development of technology to promote EOR in mature fields. Results indicate that project NPV is around US$ 3.2 million, what is significant for a small mature field. Additionally, it contributes by removing greenhouse gases (GHG) from the atmosphere by storing 0.73 million tons of CO2 over a period of 20 years. Project feasibility, as expected, was found to be very sensitive to oil price, oil production, and CAPEX.