In-situ CO2 generation for EOR by using urea as a gas generation agent

Most importantly, results of injecting urea solution (as low as 5% solution) showed superior tertiary recovery performance (as high as 37.5%) as compared to the most recent efforts at our group (29.5%) as well as similar in situ CO2 generation EOR (2.4%-18.8%) approaches proposed by others. Because of the remarkable reservoir brine compatibility of urea, even under seawater levels of divalent ions, the floods showed no detectible effect of brine composition on the recovery and/or any occurrence of formation damage. Furthermore, the preferable wettability reversal was indicated by recovered oil compositional analyses. The economic feasibility and advantages of the newly proposed technique were demonstrated. The results served as a proof of concept for in situ CO2 generation tertiary oil recovery potential for both onshore and offshore fields.