oa Physical Simulations of Petroleum Changes Related to Interaction with CO2 and CH4

Different accumulations in Brazilian marginal basins have CO2 contents varying between 0 to 80 mol %. Where the CO2 values reach their maximum, two distinct fluids were observed at the reservoir: a rich gas-condensate at the top, and a heavy oil at the bottom. The main objective of this study was to evaluate the compositional changes of oil due to the contact with CO2, in order to understand the alterations of the PVT and geochemical properties. It is evident that the mixing sequence (CO2-oil or oil-CO2) significantly alters not only the distribution of the components, but also the composition of the phases.