No abstract

Effects on the phase equilibria and volumes of C02/crude oil mixtures of adding N2, CH4, H2S, or S02 contaminants are reported. Phase equilibria data were measured at temperatures above and below the C02 critical temperature and pressures up to 240 atm. Visual observations indicated conditions which promoted solid-phase formation. The data show that contaminant gases can have a pronounced effect on C02 solubility and oil swelling. These effects must be considered in C02 source selection and recycling for enhanced oil recovery. Measured swelling factors and bubble points are compared with the predictions of an empirical correlation, and a simple Peng-Robinson equation of state which treats the mixture as a binary with the crude oil as a single pseudocomponent. Swelling factor predictions using either method are in good agreement with the measured values. Equation of state predictions of bubble-point pressure were less successful.