基于多级混合单元模型的最小混相压力计算方法

A New Approach for Calculation of Minimum Miscibility Pressure Based on a Multiple-Mixing-Cell Model

最小混相压力(MMP)是混相气体注入工程设计的关键参数之一,在MMP下,驱替效率达到100%。在本研究中,提出了一个基于多级混合单元模型的新方法来识别关键结线,从而计算出最小混相压力。多级混合单元模型是细管实验中连续气体注入过程中的一个离散模型。在该方法中,对于nc组分的体系,研究发现有nc+1个相同组成的区和nc-1个关键结线。随着注入气体批次数的增加,关键结线以反序的形式出现,如初始结线首先出现,注入结线最后出现。该研究结果有助于新方法识别所有的关键结线,因此特别适用于气体注入的研究。本方法所预测的结果与细管实验的结果和其他研究者的结果相对比是十分吻合。

A key parameter in the design of the miscible gas injection process is the minimum miscibility pressure（MMP）,at which the local displacement efficiency approaches 100%.In this paper,a new approach based on the multiple-mixing-cell model has been proposed to identify the key tie lines,and therefore to calculate the MMP.The multiple-mixing-cell model is a discrete model of the continuous gas injection process in the slim tube experiment.In this approach,for nc components,it＇s found that there are nc＋1 constant-composition zones and nc-1 key tie lines.Upon increasing the batch number of the injected gas,these key tie lines appear in a reverse order,i.e.,the initial tie line appears first and the injection tie line appears last.This finding leads to a new approach to identifying the key tie lines.This approach provides a unique solution to find all the key tie lines and is therefore particularly suitable for gas injection studies.Predicted results from the proposed approach are shown to be in excellent agreement with slim tube data and other slim tube simulators presented in the literature.