摘要
CO2驱油技术(CO2-EOR)能够在提高原油采收率的同时,将部分CO2封存于地质体中,是一项"双赢"的技术.但由于原油与CO2之间黏度相差较大以及油藏的非均质性,CO2驱油过程极易发生气窜,气窜后CO2驱油产量明显降低,在CO2中加入增稠剂提高CO2黏度是解决气窜问题最直接有效的方法.综述了目前国内外用于增稠CO2的聚合物,即含氟类、硅氧烷类、碳氢类以及含氧烃类聚合物,对现有聚合物CO2增稠剂的研究效果和其优缺点进行了对比分析.分析认为,在增稠CO2提高CO2驱油效率的研究和现场应用中,首选碳氢类和含氧烃类聚合物CO2增稠剂,并总结得出有效的聚合物增稠剂应具备亲CO2疏水基团和增稠基团、无规聚合、平均分子量为6 000～15 000的分子结构.目前尚未有兼具有效、经济和环保的CO2增稠剂产品,因此设计和合成价格更便宜、无氟、无毒、环保、高可溶性的CO2增稠剂是未来的研究方向.
Abstract
CO2 enhanced oil recovery(CO2-EOR)technology not only can improve oil recovery,but also can store the part of CO2 in the geological,which is a"double win"technology.However,due to the large viscosity difference between oil and CO2 and the heterogeneity of oil reservoirs,gas channeling occurs easily during CO2 flooding.It can significantly reduce the oil recovery of CO2 flooding.To solve this problem,the CO2 viscosity can be enhanced by using CO2 thickeners in the CO2 phase,which is the most direct and effective method.In this work,the polymers that used to thicken CO2 at home and abroad were reviewed,including fluorinated polymers,siloxane polymers,hydrocarbon polymers and oxygenated hydrocarbon polymers.By comparing and analyzing the research results and the advantages and disadvantages of existing polymer thickeners,it was found that the hydrocarbon and oxygenated hydrocarbon polymer thickeners are preferred in the research and application for enhanced CO2 viscosity to improve CO2 flooding efficiency.Furthermore,the effective polymer thickeners should have a molecular structure of CO2-philic group and thickening group,atactic polymers,and an average molecular weight of 6 000～15 000.At present,an effective,affordable and environmentally friendly CO2 thickeners has not been found,so the future research studies on CO2 thickeners must focus on designing and synthesizing less expensive,fluoride free,non-toxic,environmentally friendly and highly soluble CO2 thickeners.
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