SOLUBILITY OF CO2 AND C2H6 IN HEAVY OIL AND ITS SARA FRACTIONS

Solvent-based recovery is one of the most promising techniques to enhance heavy oil/bitumen recovery as an alternative to thermal methods. Phase behaviour study of light gases in heavy oil is therefore very important when designing operation and surface facilities for heavy oil recovery. In this study, the original oil (Cactus Lake) was first characterized into saturate, aromatic, resin, asphaltene, and maltene fractions (0.0 wt. % asphaltene). An intelligent gravimetric microbalance was used to measure the solubility of carbon dioxide and ethane in the heavy oil and its saturate, aromatic, resin, asphaltene, and maltene fractions. The measurements were carried out at 288, 294, 299, and 303K, and at pressures from 200 to 2000kPa. The standard Peng-Robinson equation of state was used to correlate the experimental results. The associated Henry's law constants were regressed and reported. The adsorbed amounts of carbon dioxide and ethane on asphaltene were correlated using the Freundlich isotherm. As for the given heavy oil sample and its fractions, carbon dioxide showed lower solubility than ethane at constant temperature, even at high pressures. It was observed that the asphaltene content affects ethane solubility quite significantly in this heavy oil when compared to carbon dioxide.