高压CO_(2)作用下低渗透岩心渗吸采油规律研究  

Study of the oil recovery trends by imbibition in low-permeability cores under high-pressure CO_(2)

作　　者：张梦园 李宾飞 陈龙坤[3] 徐正晓 辛岩 王浩 李兆敏[1,2] ZHANG Mengyuan;LI Binfei;CHEN Longkun;XU Zhengxiao;XIN Yan;WANG Hao;LI Zhaomin(State Key Laboratory of Deep Oil and Gas,China University of Petroleum(East China),Qingdao 266580,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao 266580,China;East China Sales Company Limited,CNOOC,Nanjing 210019,China;School of Petroleum and Gas Engineering and School of Energy,Changzhou University,Changzhou 213164,China)

机构地区：[1]中国石油大学(华东)深层油气国家重点实验室,青岛266580 [2]中国石油大学(华东)石油工程学院,青岛266580 [3]中海油华东销售有限公司,南京210019 [4]常州大学石油与天然气工程学院、能源学院,常州213164

出　　处：《石油科学通报》2025年第2期245-255,共11页Petroleum Science Bulletin

基　　金：深层油气全国重点实验室开放课题(SKLDOG2024-KFYB-14)资助。

摘　　要：低渗透油藏注CO_(2)开发中,CO_(2)溶于水后形成的碳酸水能够有效改善渗吸效果,进而提高油藏开发效益。本文通过测量油水界面张力、接触角和渗吸采收率,探究了温度和压力对高压CO_(2)作用下低渗透岩心渗吸采油的影响规律。结果表明,升高温度和增加CO_(2)压力均可改善油水界面特性,提高渗吸采收率。8 MPa时,温度由20℃升至80℃,界面张力增大2.25 m N·m^(-1),接触角减小15.2°。温度对油水界面特性的影响显著强于CO_(2)溶解度,随着温度升高,CO_(2)溶解度减小,但界面张力增大,岩石亲水性增强,并且原油流动性增强,故渗吸效率提高。80℃时,压力由4 MPa升至10 MPa,界面张力减小3 m N·m^(-1),接触角减小18.4°。压力通过改变CO_(2)在液相中的溶解度来影响油水界面特性,随着压力升高,CO_(2)溶解度增大,界面张力减小,岩石亲水性增强,原油流动性也增强,继而渗吸效率有效提高。升温和增压在提高渗吸效率方面存在一定的协同效应,两者共同作用下,虽界面张力仅有小幅减小,但岩石亲水性明显增强,加速了基质孔喉中原油的逸出,有效提高了低渗透岩心渗吸采收率。研究结果丰富了渗吸采油机理,能够为低渗透油藏注CO_(2)开发提供理论参考。During the development of CO_(2) injection in low-permeability reservoirs,carbonated water formed after CO_(2) dissolves in water can effectively improve the imbibition effect,and thus improve the reservoir development benefit.By measuring the oil-water interfacial tension,contact angle and imbibition recovery factor,the effect of temperature and pressure on imbibition recovery in low-permeability cores under high-pressure CO_(2) was investigated.The results show that increasing temperature and CO_(2) pressure can improve oil-water interface characteristics and enhance imbibition recovery.At 8 MPa,the temperature increas-es from 20℃to 80℃,the interfacial tension increases by 2.25 mN·m^(-1),and the contact angle decreases by 15.2°.The influence of temperature on oil-water interface characteristics is stronger than that of CO_(2) solubility.With the increase of temperature,CO_(2) solubility decreases,but the interfacial tension increases,the hydrophilicity of rock enhances,and the fluidity of crude oil increases,so the imbibition efficiency increases.At 80℃,the pressure increases from 4 MPa to 10 MPa,the interfacial tension decreases by 3 mN·m^(-1),and the contact angle decreases by 18.4°.Pressure mainly affects the oil-water interface characteristics by changing the CO_(2) solubility in the liquid phase.With the increase of pressure,the CO_(2) solubility increases,the interfacial tension decreases,the hydrophilicity of rock enhances,the fluidity of crude oil also increases,so the imbibition efficiency increases effec-tively.Heating and pressurization have a certain synergistic effect on improving imbibition efficiency.Under the combined action of the two,although the interfacial tension only slightly decreases,the hydrophilicity of the rock enhances significantly,which accelerates the escape of crude oil in the matrix pore throat and effectively improves the imbibition recovery in low-permeability cores.The research results enrich the imbibition production mechanism,and can provide theoretical reference

关 键 词：低渗透油藏 高压CO_(2) 碳酸水 渗吸 油水界面张力 接触角 

分 类 号：TE357[石油与天然气工程—油气田开发工程] P618.13[天文地球—矿床学]