CO2 flooding is an effective way to strengthen the heavy oil, but CO2 is injected into the reservoir reaches its supercritical conditions can extract heavy oil light components, heavy damage to the gel structure, leading to asphaltene precipitation, blocking pore throats.Currently studies on CO2 extraction of crude oil, mainly in the extract is to simulate an oil (such as diesel), silt and diesel oil and other research on the extraction process and the factors focused on the extraction pressure and temperature on these two issues, the real thick few studies of oil, as well as the influence of the lack of research on the extraction time.To this end, used real heavy, to extract the components before and after CO2 extraction of heavy oil was extracted and analyzed to study the role of the law of pressure, temperature and extraction time and other factors in the CO2 extraction process.The results showed that: CO2 extraction from heavy oil mainly in the lighter components (alkanes), extraction volume reached approximately 70%, with the light components are extracted, the occurrence of heavy asphaltenes coagulation precipitation.CO2;extraction effect as the pressure (10~20 MPa) increases to enhance the final extraction rate increased from 8% to 24%;but the temperature (60~90 ℃) is not the final extraction rate influence;pressure and temperature have led to increased extraction rate of increase in the extraction process, up to 7.72%/h, and the greater the pressure, the higher the temperature, the extraction rate is also the fastest to reach steady state, this time in the extraction rate of between 0.22%/h to 0.35%/h;extraction time was 1~2 h, extracted effect basically ended.%CO2驱是强化稠油开采的有效方法;但将CO2注入储层,达到其超临界条件会萃取稠油中的轻质组分,破坏稠油的胶体结构,导致沥青质析出、堵塞孔喉.目前关于CO2萃取原油的研究,主要存在被萃取物为模拟油(如柴油)、含油泥砂和油渣等和对萃取过程影响因素的研究集中在萃取压力和温度上这两个问题,对于真实稠油的研究较少,以及对萃取时间的影响规律研究不足.为此,利用真实稠油,对CO2萃取前稠油的物性和萃取后萃取物组分进行分析,研究在CO2萃取过程中压力、温度和萃取时间等因素的作用规律.结果表明:CO2主要从稠油中萃取出轻质组分(烷烃),萃取量达到大约70%;随着轻质组分被萃取,重质的沥青质发生聚沉、析出.CO2萃取作用随着压力(10~20 MPa)的增大而增强,最终萃取率从8%增大到24%;但温度(60~90 ℃)对于最终萃取率的影响不大;压力和温度的升高都导致萃取过程中萃取增长率的升高,最高可达7.72%/h;且压力越大、温度越高,萃取率也就最快达到平稳状态,此时萃取增长率在0.22%/h~0.35%/h之间;萃取时间为1~2 h,萃取作用基本结束.
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