Gas Solubility and Acidity Effects on Heavy Oil Recovery at Reservoir Conditions

Only few attempts have considered gas flooding as means of heavy oil recovery and subsequently have investigated into gas solubility towards heavy crudes. Even more, the credit has been only given to specific methods including thermal treatment and chemical injection. Considering a ternary phase system formed between the extracting fluid (CO₂), a heavy crude and brine which exist within the reservoir, not only this work has addressed the issue of heavy oil recovery using CO₂ as extracting fluid but also, it has demonstrated the combined effects of gas solubility and acidity induced by gas injection. Carried out at laboratory scale, extracting gas, at its supercritical state has been injected in a PVT cell within which a constant temperature of 50°C was kept constant for 45hrs. CO₂ was found to be highly soluble in the mixture with a peak of dissolution around 10 MPa which corresponds to bubble pressure point. These results were found to match with the literature. Moreover, it has been able to demonstrate existence and the occurrence of a certain chemistry taking place during supercritical CO₂ injection and flooding which have a great impact depending on the acidity induced within reservoir.