Experimental Investigation of the EOR Performances of Carbonated Water Injection in Tight Sandstone Oil Reservoirs

Carbonated water injection (CWI) refers to a method that using carbonated water (CO2 dissolved in water under high pressure) as injected fluid to displace oil in the reservoir. At present there is no report about CWI study in tight oil reservoirs. Based on the reservoir condition and material of a tight formation in Changqing Oilfield, we investigate the core displacement performances of CWI, water alternating Gas (CO2), surfactant injection, and active carbonated water (adding surfactant in carbonated water) injection. Experimental results demonstrate that CWI recovery is 7.2% more than water injection, and 2.7% more than WAG injection; ACWI achieves the best performance with 10% more oil recovery than water injection.