醚类助溶剂在超临界二氧化碳中的浊点压力及对二氧化碳-C_(16)混相压力的影响  

Cloud-point Pressure of Ether Cosolvents in Supercritical CO_(2) and Their Effect on Miscibility Pressure of CO_(2)-C16

作　　者：张欢 宫厚健[1] 孙君腾 张明明 吕威 杨小珂 CO-CZHANG Huan;GONG Houjian;SUN Junteng;ZHANG Mingming;LYU Wei;YANG Xiaoke(School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,P R of China)

机构地区：[1]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《油田化学》2024年第1期77-84,共8页Oilfield Chemistry

基　　金：国家自然科学基金“CO_(2)活性体系提高陆相富有机质页岩油采收率机理研究”(项目编号52174049)。

摘　　要：助溶剂和CO_(2)对提高原油采收率有着协同增效作用。研究超临界CO_(2)-助溶剂体系的浊点压力和与原油的混相压力,对于CO_(2)提高原油采收率及CO_(2)埋存有着重要意义。使用改进的CO_(2)相平衡实验装置,采用根据光敏原理改进的测量方法,研究了3种助溶剂二乙二醇二甲醚(DDME)、三乙二醇二甲醚(TEDM)、四乙二醇二甲醚(TGDE)在CO_(2)中的浊点压力,考察了温度、助溶剂加量、助溶剂类型的影响;然后将这3种醚类助溶剂和常见的助溶剂乙醇对比,研究其降低CO_(2)-C_(16)混相压力的效果。结果表明,随着温度的升高,DDME、TEDM、TGDE的浊点压力逐渐升高,且呈现出低临界会溶温度(LCST)相行为。随着加量的增大,DDME、TEDM、TGDE的浊点压力逐渐升高,但增幅较小。DDME、TEDM、TGDE的极性越来越大,其与CO_(2)之间的分子间作用力逐渐减弱,导致浊点压力依次升高。在3种结构相似的醚类助溶剂中,DDME的浊点压力最低,TGDE的浊点压力最高。当DDME的质量分数为3.0%、温度为60℃时,浊点压力仅为10.14 MPa。DDME降低CO_(2)-C_(16)混相压力的效果最好,在50℃时,1.0%DDME可使混相压力的降幅达到11.25%,高于乙醇的10.62%。在温度低于50℃时,TEDM的作用效果优于乙醇,但高温下乙醇效果略优于TEDM和TGDE。DDME具有较低的浊点压力和较好的降低混相压力的能力,与CO_(2)具有较好的配伍性,也适用于地层压力较低的油藏。Carbon dioxide and cosolvents have synergistic effect on enhancing oil recovery.Measuring the cloud-point pressure and miscibility pressure is of great significance to improve oil recovery and CO_(2) sequestration.Based on the photosensitive principle,the cloud-point pressure of diethylene glycol dimethyl ether(DDME),triethylene glycol dimethyl ether(TEDM)and tetraethylene glycol dimethyl ether(TGDE)in CO_(2) and the effects of temperature,concentration and type of the cosolvents were obtained using the improved carbon dioxide phase equilibrium experimental device.Then the effects of cosolvents on decreasing the miscibility pressure of CO_(2)-C16 were investigated and compared with that of ethanol.The results showed that the cloud-point pressure of DDME,TEDM and TGDE all increased with the increase of temperature,and then the phase behavior of low critical solution temperature(LCST)was present.With the increase of cosolvent dosage,the cloud-point pressure of DDME,TEDM and TGDE all increased with a low increasing rate.Because the polarity became larger and larger in the order of DDME,TEDM and TGDE,the interaction force between cosolvent and CO_(2) became weaker and weaker,leading to the increase of cloud-point pressure.Among the three ether cosolvents with similar structure,DDME had the lowest cloud-point pressure,while TGDE had the highest cloud-point pressure.When the mass fraction of DDME was 3.0%,the cloud-point pressure was only10.14 MPa at 60℃.Moreover,DDME had the best effect to decrease the miscibility pressure between CO_(2) and C16.DDME with the dosage of 1%could decrease the miscibility pressure with the decreasing degree of 11.25%,which was larger than that of ethanol(10.62%)at 50℃.When the temperature was lower than 50℃,the effect of TEDM was better than that of ethanol.At a higher temperature,the effect of ethanol was slightly better than that of TEDM and TGDE.DDME,with a low cloud-point pressure value,a high ability to decrease the miscibility pressure,and a good compatibility with carbon diox

关 键 词：超临界二氧化碳 醚 助溶剂 浊点压力 混相压力 

分 类 号：TE349[石油与天然气工程—油气田开发工程]