Carbonated Water Injection: a Green Solution for Heavy Oil Production

Abstract

Summary The performance of CWI is studied using five different oils by various viscosities through a series of high-pressure core flooding experiments. The results revealed the capability of CWI to recover higher incremental oil in comparison with water injection (WI). The creation of a low resistance flow channel and low oil recovery in WI, is compensated by CO2 diffusion from CW to oil, subsequent viscosity reduction and oil swelling during CWI. Also it found that higher reservoir oil viscosity has an adverse effect on WI and CWI performances which leads, the mobility ratio deviates from the ideal value and poor sweep efficiency causes lower oil recovery. Moreover, comparing the results of CWI and WI revealed that, nearly 28% oil recovery improvement was obtained in oil A, that reached 49.5% for oil E, with higher oil viscosity. This improvement demonstrated the advantage of CWI for heavy oil reservoirs. From the CO2 storage point of view, a remarkable fraction (ranges between 20% and 33% for different oils) of total volume of injected CO2 was stored at CWI. Thus, it was concluded that CWI has a great potential to permanently store the injected CO2 while significantly improving oil recovery in heavy oil systems.