摘要
乳化作用是稠油油藏化学驱提高采收率的主要机理之一,稠油在多孔介质中的乳化与油藏温度、驱油剂浓度密切相关.通过乳化实验研究了稠油形成水包油乳状液所需驱油剂的临界乳化浓度与温度的关系,利用高温高压微观可视驱油装置研究了稠油化学驱过程中原油乳化及运移规律.实验结果表明:乳化实验温度越高,原油越易于被乳化,所需的驱油剂的临界乳化浓度越低;当实验温度由30 ℃增加到90 ℃,临界乳化浓度下降了90％.稠油化学驱的微观驱油实验过程中,稠油在多孔介质中的乳化过程存在3种模式.在多孔介质中,当驱油剂的浓度小于该温度下稠油乳化所需驱油剂的临界乳化浓度时,稠油乳化模式为原油在喉道处经历卡断分散、运移、聚并;当驱油剂的浓度大于该温度下稠油乳化所需驱油剂的临界乳化浓度时,稠油乳化模式为卡断乳化、运移、再乳化、再运移;当驱油剂的浓度远大于该温度下稠油乳化所需驱油剂的临界乳化浓度时,稠油乳化模式为接触、剥离、运移.因此,开展稠油化学驱时,在控制成本的前提下,尽可能提高驱油剂的浓度,可实现稠油的高效乳化,进而提高采收率.
Abstract
Emulsification is one of the main mechanisms of chemical flooding to enhance oil recovery in heavy oil reservoirs.The emulsification of heavy oil in porous media is closely related to reservoir temperature and oil-displacing agent concentration.The re-lationship between the critical concentration and temperature of the oil-displacing agent required to form oil in water(O/W)emul-sions in heavy oil was studied by emulsification experiment.The emulsification and migration rules of crude oil during chemical flooding of heavy oil were studied by using high-temperature and high-pressure microscopic visual oil displacement devices.The re-sults show that a higher temperature in the emulsification experiment indicates that the crude oil is easier to emulsify,and the criti-cal emulsification concentration of the required oil-displacing agent is lower.The critical emulsification concentration decreases by 90％when the temperature increases from 30 ℃ to 90 ℃ during the experiment.There are three modes of emulsification of heavy oil in porous media during microscopic oil displacement experiments for chemical flooding of heavy oil:the emulsification mode of heavy oil shows dispersion,migration,and coalescence at the throat in porous media when the concentration of the oil-displacing agent is less than the critical emulsification concentration of the oil-displacing agent required for heavy oil emulsification at this tem-perature;the emulsification mode of heavy oil indicates emulsification,migration,re-emulsification,and re-migration when the concentration of the oil-displacing agent is greater than the critical emulsification concentration of the oil-displacing agent required for heavy oil emulsification at this temperature;the emulsification mode of heavy oil is manifested as contact,stripping,and migra-tion when the concentration of the oil-displacing agent is much larger than the critical emulsification concentration of the oil-displacing agent required for heavy oil emulsification at this temperature.Therefore,the concentration of the oil-displacing agent should be increased as much as possible to achieve efficient emulsification of heavy oil and improve oil recovery under the premise of controlling the cost when chemical flooding of heavy oil is carried out.
基金项目
国家自然科学基金企业创新发展联合基金(U20B6003)
国家重点研发计划(2018YFA0702400)
维普
万方数据