界面张力及乳化效果对提高采收率的贡献

以中国石油冀东油田原油为研究对象,筛选并评价了具有不同界面张力及乳化效果的4组驱油体系,研究了界面张力与乳化效果对提高原油采收率的贡献。实验结果表明,油水界面张力与原油乳化效果之间没有明显的一致性,当以0.1%(w)的Na_2CO_3或0.5%(w)Na_2CO_3+0.3%(w)JS-33复配体系为驱油剂时,界面张力均可达到超低,但乳化效果较差,析水率分别高达91.7%和83.3%,而原油采收率提高值只有8.9%和12.4%;当以0.5%(w)的Na_2CO_3或0.5%(w)Na_2CO_3+0.5%(w)JS-33复配体系为驱油剂时,界面张力分别为10^-2和10^-3数量级,乳化效果较好,析水率分别为1.7%和0,原油采收率提高值达27.5%和24.4%。乳化效果好的驱油体系原油采收率提高值要高于超低界面张力体系,乳化效果相比界面张力而言对提高采收率的贡献占主要部分。

Contribution of interfacial tension and emulsification effect on enhanced oil recovery

Four groups of oil displacement systems with different interfacial tensions and emulsification effects were screened and evaluated for low permeability reservoir in eastern Hebei. The influence of interfacial tension and emulsification effect on enhanced crude oil recovery was also investigated. The results showed that there was no obvious consistency between the oil/water interfacial tension and oil emulsification effect. If the compound system of 0.1%(w)Na2CO3 or 0.5%(w) Na2CO3+0.3%(w)JS-33 is used as oil displacement agent,the interfacial tension could achieve ultra-low;but the emulsification effect was poor,water drainage rate would be 91.7% and 83.3% respectively;the value of enhanced oil recovery were only 8.9% and 12.4% respectively. If the compound system of 0.5%(w)Na2CO3 and 0.5%(w)Na2CO3+0.5%(w)JS-33 is used as oil displacement agent,the interfacial tension could be on the order of 10^-2 and 10^-3 respectively;but the emulsification effect was good,water drainage rate would be only 1.7% and 0 respectively;while the value of enhanced oil recovery could be 27.5% and 24.4%. The oil displacement system which had good emulsification effect could get higher value of improved oil recovery than that with ultra-low interfacial tension. This suggested that compared with interfacial tension,emulsification effect occupies the main part for improving oil recovery.