Percolation Model for Permeability Reduction in Porous Media by Continuous-Gas Foams

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• 作者：Randy D. Hazlett and Mary J. Furr
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2000
• 出版时间：August 2000
• 年：2000
• 卷：39
• 期：8
• 页码：2709 - 2716
• 全文大小：155K
• 年卷期：v.39,no.8(August 2000)
• ISSN：1520-5045

文摘

Percolation modeling concepts are invoked to construct estimates of gas permeability modificationas a result of the introduction of low concentration or poorly stabilizing surface-active agents ina gas injection process in porous media. The creation of a low number of quasi-stable lamellaein porous media results in an increased stationary gas saturation and is modeled as a reductionin effective connectivity of the medium. Medium connectivity impacts the minimum free gassaturation for continuity and the associated characteristic length scale strongly correlated withpermeability. The complex process of in situ foam generation and propagation is modeled througha foam efficiency parameter and, ultimately, through the assertion of a roughly constant mobilegas saturation for good foaming agents. The model is shown to adequately portray literaturefoam relative permeability measurements with mobile gas saturation values consistent withthe reported values for similar porous media systems. In the limit where gas percolation is lost,a second mode of transport involving bubble propagation is observed. The two regimes of foamtransport have been observed in visualization experiments for gas injection into a brine-saturated,matched refractive index sandpack. For many processes, the dramatic decrease in gas mobilityassociated with propagation of lamellae is detrimental, making process design and modelingfor the continuous-gas regime important.