高压CO_2对离子型表面活性剂水溶液与风城超稠原油界面张力的影响

The Influence of high-pressure CO_2 on the interfacial tension between Fengcheng oilfield extra-heavy oil and ionic surfactant solution

采用轴对称悬滴形状分析技术,测量了30℃与50℃下,CO_2压力在0.1~10.0 MPa范围内,离子型表面活性剂水溶液/CO_2/风城超稠原油体系中油水两相的界面张力。实验结果表明,表面活性剂水溶液和原油的平衡界面张力随着CO_2压力的增大而增大,高压CO_2的存在能有效降低十二烷基磺酸钠(SDS)水溶液/原油体系与纯水/原油体系中油水两相的界面张力;而在十烷基三甲基溴化铵水溶液/原油体系和十二烷基三甲基氯化铵(DTAC)水溶液/原油体系中,高压CO_2的存在则会使得油水两相界面张力增大。溶解在SDS水溶液中的CO_2能够协助SDS乳化原油,而溶解在DTAC水溶液中的CO_2则不利于DTAC乳化原油。

In this study,the interfacial tension（IFT） between Fengcheng oilfield extra-heavy oil and ionic surfactant solution was measured by utilizing the axisymmetric drop shape analysis technique in the presence of CO2 ranging from 0.1-10.0 MPa at 30 ℃ and 50 ℃ respectively. The experimental results showed that the equilibrium IFT between crude oil and surfactant solution increased as the CO2 pressure increased,and the presence of high-pressure CO2 led to the effective reduction of IFT of pure water/crude oil system and sodium dodecyl sulfonate（SDS） solution/crude oil system. However,for dodecyl trimethyl ammonium chloride（DTAC） solution/crude oil system and decyl trimethyl ammonium bromide solution/crude oil system,the IFT increased with the presence of high-pressure CO2. Furthermore,the dissolution of CO2 into SDS solution improved the emulsifying ability of SDS for crude oil,while the dissolution of CO2 into DTAC solution reduced emulsifying ability of DTAC for crude oil.