Study on the Extraction Process during CO2 Flooding in Oil Reservoir and its Effects on Crude Oil Properties
CO2 under supercritical state has been used in the oil field to flood oil. The previous studies are concentrated on the advantages of CO2 flooding, such as oil expansion and viscosity decrease. The disadvantages are less mentioned. In this paper, the negative effects caused by the CO2 extraction are studied. The CO2 extraction process from crude oil in the porous medium in oil reservoir is analyzed. Six term of condition, which caused the extraction, is summarized. A concept of differential extraction in porous medium is advanced for the first time. The process of extraction is simulated using three crude oil samples on PVT test under condition of high temperature and pressure. The quantity of extraction is measured for the three crude oils and the extent of extraction under different pressure is also measured by experiment. The change in viscosity and component between the original oil and residual oil through extraction process is compared. The result shows that the viscosity change is great. The viscosity of residual oil after extract is 1.1~2 times higher than that of original crude oil. The research proves that the extraction can lead to the marked viscosity increase for heavy crude oil, which finally adds the difficulty in the development and decreases the oil production. The authors suggest that CO2 flood technique ought to be used in light oil reservoir preferentially. The ways to overcome the negative effects is also studied and 3 kind methods are proposed. The study provides technical reference for the practical application of CO2 flooding.
CO2 under supercritical state Extraction Oil Reservoir Porous Medium
Shenglai YANG Rong SUN Dazhen HANG Ming WU Hui DENG Li CHEN
CMOE Key Laboratory of Petroleum Engineering in China University of Petroleum, Beijing, China 102249
国际会议
The 5th International Conference on Separation Science and Technology(第五届国际分离科学与技术会议)
北京
英文
2007-10-14(万方平台首次上网日期,不代表论文的发表时间)