CO_2乳液的界面特性对其渗流特征的影响

Influence of CO_2 emulsion interfacial characterization on porous flow

CO_2乳液在驱油过程中能够有效控制CO_2流度,大幅改善CO_2驱油效果,提高采收率。选择AOT作为CO_2乳液用表面活性剂,通过TRACKER-H界面流变仪测定AOT水溶液与CO_2体系在不同温度压力条件下的界面特性,通过岩心实验测定不同温度压力条件下CO_2乳液的封堵和调剖分流效果。结果表明:随着压力的增大,CO_2乳液界面张力随之降低,界面黏弹性随之增大;随着温度的增加,CO_2乳液界面张力增加,界面黏弹性降低;温度越高越不利于乳液的封堵,压力越高越有利于乳液的封堵,这与体系界面特性研究所得的结果相对应,说明CO_2乳液的封堵效果与其界面特性有关;温度和压力通过影响CO_2乳液的界面特性从而影响其渗流特征,CO_2乳液的强度越高、体系界面张力越低、界面黏弹性越好,其分流效果也会越明显。

In the process of oil displacement,CO2emulsion can effectively control the mobility of CO2which significantly improves the CO2flooding effect and EOR.The AOT was selected as surfactants for CO2emulsion.And the interfacial property of AOT aqueous solution and CO2was characterized through TRACKER H interfacial rheometer at different temperatures and pressures.Then the CO2emulsion plugging and profile control shunt effect were evaluated through the core plugging experiment under different temperatures and pressures.It is found that with the increase of pressure,the interfacial tension of CO2emulsion decreases,while the interfacial viscoelasticity increases.And with the increase of temperature,the interfacial tension of CO2emulsion increases,but the interfacial viscoelasticity decreases.It is also concluded that the high temperature is unfavorable to the emulsion plugging,while the high pressure is favorable to the emulsion plugging,which corresponds to the interfacial viscoelasticity,indicating CO2emulsion plugging effect is related to its interfacial viscoelasticity.The results show that the temperature and pressure can affect the porous flow of CO2emulsion via influencing its interfacial properties.Higher the strength of the CO2emulsion,lower interfacial tension and better viscoelasticity can lead to signficant shunt effect.