Experimental study on combination hot water-CO2-chemical flooding with effects on oil recovery and heat transfer

Abstract

CO2 flooding has been used widely for enhanced oil recovery (EOR), it can be co-injected with hot water into reservoir to make up the limitation of hot water flooding. In this paper, combination hot water-CO2-chemical flooding technique was proposed for EOR by experimental study and the characteristic of oil recovery and heat transfer for the flooding was focused. Firstly, by the built experiment, the comparison of the proposed flooding with other five conventional floodings was investigated, and the CO2 storage during hot water –CO2-chemical flooding was also concerned. Then, the effect of Joule-Thompson cooling and injection parameters on heat transfer and oil recovery of combination hot water-CO2-chemical flooding was analyzed by exprimant. The experimental results showed that compared the five conventional floodings, the proposed flooding got the highest oil recovery of 63%, and the CO2 storage efficiency for it could reach to 80.61%. Also, it was found that the effect of Joule-Thompson cooling on reservoir temperature was strengthened with increase of CO2 injection pressure which reduced the temperature beside inlet of reservoir, and affected heat transfer of the whole reservoir ultimately. However, during the combination hot water-CO2-chemical flooding, the heat transfer of reservoir mainly depended on the hot water injection. Also, it could exist the best injection temperature of hot water for the flooding to obtain the highest oil recovery.