多相混合渗流理论研究  

Study on the theory of multiphase mixed seepage in porous media

作　　者：朱维耀[1,2] ZHU Wei-yao(School of Civil and Resource Engineering,University of Science and Technology Beijing,Beijing 100083,China;Institute of Applied Mechanics,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]北京科技大学应用力学研究所,北京100083

出　　处：《工程科学学报》2023年第5期833-839,共7页Chinese Journal of Engineering

基　　金：国家自然科学基金(面上项目)资助项目(51974013)。

摘　　要：针对现有多相渗流理论假设各相均为连续相、无相间交换,不能表征相对渗透率端点附近出现非连续相,未能考虑多相混合、界面作用、相间传质传输等多相掺混复杂流动的问题,本文把多相渗流流体作为一个总体即混合流体,研究多相流体在多孔介质中传输,包含不相溶、相界面变化、相间传质传输、混合相,搞清各相间交换关系和流动机制,即多相混合流动规律.首先基于平衡热力学第一、第二定律,考虑渗流过程中的多相体系平衡条件,推导出了渗流过程中多相体系平衡热力学关系式,之后运用多相流体全质量守恒定律和渗流过程中多相体系平衡热力学公式,建立了多相流体混合渗流理论模型,分析了多相混合渗流理论与传统多相渗流理论的关系,提出了多相混合渗流的理论.指出多相体系流体总的渗流速度不仅与压力梯度成正比,还与多相体系混合渗流程度有密切关系,其中混合渗流程度是饱和度、界面张力、压力梯度和孔隙度的函数.研究结果表明,多相混合渗流理论深刻地反映了多相流体混合渗流的本质,揭示了多相流体混合渗流的内在作用变化规律,弥补了多相渗流理论用单相达西定律推广到了多相渗流中的不足,多相混合渗流理论涵盖了传统多相渗流理论,具有重大的理论意义和应用价值.The existing theory of multiphase seepage can neither explain the cause of the discontinuous phase near the end of relative permeability nor consider the complex flow of multiphase mixing, interface interaction, and mass transfer between phases. In this paper, all phases in pores were treated as a mixed fluid of one phase to investigate multiphase seepage characteristics. Multiphase fluid transport in porous media was studied, including phase dissolution, phase interface change, phase mass transfer, and mixed phases.The exchange relation and flow mechanism of multiphase fluid in porous media, i.e., the law of multiphase mixed flow, are clarified. On the basis of the first and second laws of thermodynamics, the framework of the thermodynamic equilibrium relations of a multiphase system was constructed considering phase equilibria during the seepage process. Consequently, a theoretical model of multiphase mixed seepage was established by combining the multiphase mass conservation and multiphase equilibrium thermodynamics equations in the seepage period, which leads to the proposed mixed seepage theory that this paper focuses on. Then, the similarities and differences between conventional multiphase seepage theory and mixed seepage theory were discussed and described comparatively. The analysis and results indicate that the overall velocity of a multiphase system is positively correlated with the pressure gradient, as well as an outcome of the seepage mixing degree defined as a function of saturation, interfacial tension, pressure gradient, and porosity.Additionally, the seepage mixing degree is the product of the mixed seepage coefficient, which reflects the interaction between phases,and the mobility. Defining the seepage mixing degree can convert the motion equation of mixed seepage into a form similar to the generalized Darcy’s law, reflecting the fundamental distinction between these two theories. A multiphase system is considered to comprise continuous phases in conventional multiphase seepage theory. Howeve

关 键 词：渗流理论模型 渗流热力学 多相混合 混合渗流程度 渗流本质规律 

分 类 号：TE312[石油与天然气工程—油气田开发工程]