The impacts of citrate ester surfactants on the MMP, extraction and swelling behaviors between CO2 and oil were investigated to enhance shale oil recovery. Firstly, the dissolution behaviors of citrate ester in CO2 and the influence of citrate ester on the MMP between CO2 and oil were investigated by the phase-transition-point measurement. Then, the effects of citrate ester on the extraction and swelling behaviors between CO2 and oil were explored by a newly-designed method. At last, the effect of surfactant on the shale oil recovery during CO2 huff-n-puff process was discussed. The results show that compared with citrate ester B, citrate ester A has a lower cloud-point pressure and higher effect to decrease the MMP of oil and CO2. The extraction ratio and swelling ratio both increase with the increase of CO2 pressure and the increase of oil content in the oil and CO2 systems. Citrate ester A can enhance the extraction and swelling effects of CO2 to oil and the promoting effect increases with the increasing surfactant concentration. The presence of 1% citrate ester A in CO2 can enhance the oil recovery about 10% caused by the decreasing MMP, improvements of extraction, swelling and solution-gas-drive effects.

中文翻译：

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柠檬酸盐酯表面活性剂对 CO2 和石油之间 MMP、萃取和溶胀行为的影响：提高页岩油采收率的应用


研究了柠檬酸盐酯表面活性剂对 CO2 和石油之间 MMP、萃取和溶胀行为的影响，以提高页岩油采收率。首先，通过相变点测量研究了柠檬酸盐酯在 CO2 中的溶解行为以及柠檬酸盐酯对 CO2 和油之间 MMP 的影响。然后，采用新设计的方法探究柠檬酸盐酯对 CO2 和石油之间萃取和溶胀行为的影响。最后，讨论了表面活性剂对 CO2 huff-n-puff 过程中页岩油采收的影响。结果表明，与柠檬酸盐酯 B 相比，柠檬酸盐酯 A 具有更低的浊点压力和更高的降低石油和 CO2 的 MMP 的效果。提取率和溶胀率均随着 CO2 压力的增加以及油和 CO2 系统中含油量的增加而增加。柠檬酸酯 A 可以增强 CO2 对油的萃取和溶胀效果，并且随着表面活性剂浓度的增加，促进效果增加。CO2 中 1% 柠檬酸酯 A 的存在可以提高约 10% 的石油采收率，这是由于 MMP 降低、萃取、溶胀和溶液-气体驱动效应引起的。