Evaluation of interfacial tension (IFT), oil swelling and oil production under imbibition of carbonated water in carbonate oil reservoirs

Carbonated water injection into oil reservoirs is known as a high-efficiency enhanced oil recovery (EOR) method that can be a solution for increasing the sweep efficiency in CO2 injection projects. The mechanisms of this method include oil swelling, wettability alteration, dissolution of the reservoir rock and reducing interfacial tension (IFT). In this work, carbonated water-oil IFT and oil swelling at various pressures, temperatures and salinities resulted from formation water dilution were measured and studied using pendant drop experiments. The wettability of the reservoir rock was investigated by contact angle tests and the oil recovery by carbonated water imbibition was demonstrated by performing imbibition experiments. The results confirm the capability of carbonated water to change the parameters to the further production, in such a way that oil recovery values at 10.342 MPa and 80 degrees C, and the salinities of ten and twenty times diluted formation water were 55.68, 62.95 and 68.52%, respectively. Wettability of carbonate rock altered to water-wet and IFT reduced to 5.039 mN/m. (C) 2020 Elsevier B.V. All rights reserved.