聚醋酸乙烯酯及两亲性表面活性剂对二氧化碳增稠作用的研究

发布时间：2017-12-26 19:00

本文关键词：聚醋酸乙烯酯及两亲性表面活性剂对二氧化碳增稠作用的研究　出处：《华东理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：采用超临界二氧化碳(scCO_2)作为压裂液可以有效提高油气采收率,然而由于其较低的粘度,在驱油时容易产生粘性指进和气窜现象,因而需要增加其粘度。本文采用偶氮二异丁腈作为引发剂,采用可逆加成-断裂-链转移(RAFT)聚合合成了不同分子量的四臂聚醋酸乙烯酯(PVAc),并采用高压落球粘度计研究了以乙醇为共溶剂的条件下,不同分子量以及不同浓度的四臂PVAc对CO_2的增稠效果,在四臂PVAc浓度为1.0 wt%,乙醇浓度为5.0 wt%时,其对CO_2粘度提升幅度为31%～55%。分别利用表面活性剂聚乙二醇三甲基壬基醚(TMN-6)和全氟聚醚(PFPE)构建了 CO_2/水乳液和水/CO_2微乳液,对其粘度进行了测定。结果表明,稳定的CO_2/水乳液体系,其粘度相较于CO_2甚至水的粘度均有很大提高。在25～40℃、10～25MPa、mH2O/mCO_2介于2:8～5:5,表面活性剂含量为0.2～1.5 wt%的条件下,乳液体系的粘度介于3.78～13.20 mPa·s,为水的5～15倍;且乳液体系的粘度随表面活性剂TMN-6浓度的增加、CO_2压力的升高、温度的降低以及mH2O/mCO_2的增加而有不同程度的增大。论文还比较了不同表面活性剂浓度下乳液的流动活化能Ea*和流动活化体积V*,结果表明,随着表面活性剂浓度的增加,CO_2/水乳液体系粘度与温度、压力的相关性也逐渐增加。相比于乳液体系,水/CO_2微乳液对CO_2粘度提升幅度并不明显。
[Abstract]:Supercritical carbon dioxide (scCO_2) is used as fracturing fluid to improve oil and gas recovery. However, because of its low viscosity, viscous fingering and gas channeling are prone to occur during oil displacement, so viscosity is needed. This paper uses two azo isobutyronitrile as initiator by reversible addition fragmentation chain transfer polymerization (RAFT) of different molecular weight four arm poly vinyl acetate synthesis (PVAc), and the use of high voltage falling ball viscometer was studied with ethanol as co solvent under the condition of different molecular weight and different concentration of four arm PVAc to CO_2 thickening effect, in the four arm PVAc concentration was 1 wt%, the ethanol concentration was 5 wt%, the viscosity of CO_2 increase from 31% to 55%. CO_2/ water emulsion and water /CO_2 microemulsion were prepared by using surfactant, polyethylene glycol three methyl nonyl ether (TMN-6) and perfluorinated polyether (PFPE) respectively, and their viscosity was determined. The results show that the viscosity of the stable CO_2/ water emulsion system is greatly improved compared with the viscosity of CO_2 and even the water. In 25 ~ 40 DEG C, 10 ~ 25MPa, mH2O/mCO_2 from 2:8 to 5:5, the surfactant content is 0.2 ~ 1.5 wt%, the viscosity of emulsion is between 3.78 ~ 13.20 mPa - s, water 5 to 15 times; and the increase of the viscosity of emulsion system with surfactant, the concentration of TMN-6 CO_2 the increase of pressure, the decrease of temperature and the increase of mH2O/mCO_2 increases. The flow activation energy Ea* and flow activation volume V* of emulsion under different surfactant concentrations were compared. The results showed that the correlation between viscosity and temperature and pressure of CO_2/ aqueous emulsion increased with the increase of surfactant concentration. Compared with the emulsion system, the viscosity of water /CO_2 microemulsion has no obvious increase in the viscosity of CO_2.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.7;TQ116.3

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