Análise da viabilidade técnico-econômica para injeção de CO2 em projetos de recuperação avançada de petróleo

Abstract

With the discovery of the pre-salt in Brazil in 2006, it raised expectations of an increase in oil production, but with that new challenges emerged, a race in search of technologies that would make production viable and the discovery of new techniques to extract oil from a more efficient form of reservoirs below the salt layer. Thus, there were some demands for the development of specific techniques to make exploration economically viable. One of the alternatives was to invest in advanced recovery methods to extract the maximum oil from a reservoir, and one of the alternatives was the injection and reinjection of miscible CO2 acting in three ways, both invading areas that were not previously invaded by water, reducing the interfacial tensions and also as reducing the oil saturation to approximately 5% of the porous volume (PV), where the previous water invasion had reduced to only 25% of the VP and the miscibility occurs in multiple contacts, the injected gas comes into contact with oil, it vaporizes the medium and heavy fractions, thus enriching carbon dioxide under the conditions of temperature and pressure acting for miscibility, this generates a displacement front towards the producing well, leaving behind the extra-heavy oil fractions. Based on this, a base model of reservoirs with characteristics that enables the injection of CO2 was used. It was necessary to use a computational simulation tool, the CMG (Computer Modeling Group) software, widely used in the oil industry, enabling the prediction of production behavior, in addition to providing data for economic evaluation. As the oil used in the simulation model is a light fluid, with 8% CO2 in its composition, it is a model similar to that found in the pre-salt. The mesh model chosen for the simulation was the 5-spot, which refers to a configuration of 4 injection wells and a producer well and were simulated in three CO2 injection flows: 1000 m3/day, for 2000 m3/day and 3000 m3/day. Thus, as the accumulated oil production and accumulated water production data over the 10 years of the project. These two factors were used to calculate the Net Present Value (NPV), which uses CAPEX, OPEX and cash flow as calculation parameters. The analysis of CO2 injection at 1000 m³/day showed the best result, with a NPV around US$ 60,000,000.00, and a payback of five years, despite its accumulated oil volume during the 10 years of the project. less than other CO2 injections. The other results with CO2 with an injection of 2000 m³/day and 3000 m³/day had a NPV of US$ 50,000,000.00 and US$ 20,000,000.00 and payback of 6 and 9 years respectively.