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注CO2混相气正在成为世界上提高轻油油藏采收率最受欢迎的采油工艺。为了改善注气项目的经济情况,准确确定混相条件至关重要。在三元流体系统的相态研究中广泛使用混相能力和溶解度这两个术语。显然人们对这两个术语之间的区别仍然有些模糊,导致在一些地区把这两个术语混同使用。因此,需要弄清这两个量与界面张力(IFT)的相互关系。最近有文献报道了一种新的试验技术———零界面张力(Vanis-hing Interfacial Tension,VIT),应用这种技术建立了混相能力与油气系统的IFT的相互关系。为此,选择了由苯、乙醇和水组成的三元流体系统,因为这些物质的相态和溶解度资料容易获得。应用液滴形状分析(DSA)技术以悬滴方式测量了不同乙醇富集度时水溶乙醇中苯的IFT。试验结果表明,VIT技术也可确定三元流体系统的混相能力。IFT测量结果与溶解度资料的比较结果,除了证实溶解度和混相能力之间的明显区别以外,还表明这两种变量之间存在密切的相互关系。
CO2 mixed gas injection is becoming the world’s most popular oil recovery process to improve oil recovery. In order to improve the economics of gas injection projects, it is crucial to accurately determine the conditions of the miscible phase. In the study of phase behavior of ternary fluid systems, the two terms of miscibility and solubility are widely used. Clearly, the distinction between the two terms is still somewhat vague, leading to a mix of these two terms in some areas. Therefore, we need to understand the relationship between these two quantities and interfacial tension (IFT). Recently, a new experimental technique, Vanis-hing Interfacial Tension (VIT), has been reported in the literature. The application of this technique establishes the interrelationship between the miscibility and the IFT of the oil and gas system. For this reason, a ternary fluid system consisting of benzene, ethanol and water has been chosen because of the easy availability of phase and solubility data for these substances. The droplet form was used to measure the IFT of benzene in water-soluble ethanol with different ethanol concentration by drop shape analysis (DSA). The experimental results show that the VIT technique can also determine the miscibility of a ternary fluid system. A comparison of IFT measurements with solubility data, in addition to demonstrating significant differences between solubility and miscibility, also indicates a close correlation between these two variables.