Influence of Wettability and Saturation on Liquid-Liquid Interfacial Area in Porous Media

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• 作者：Vivek Jain ; Steven Bryant ; and Mukul Sharma
• 刊名：Environmental Science & Technology
• 出版年：2003
• 出版时间：February 1, 2003
• 年：2003
• 卷：37
• 期：3
• 页码：584 - 591
• 全文大小：197K
• 年卷期：v.37,no.3(February 1, 2003)
• ISSN：1520-5851

文摘

The knowledge of the area of interfaces between phasesis important to understand and quantify many flow andtransport processes in porous media. In this work, we applythe interfacial tracer technique to study the dependenceof fluid-fluid interfacial area on saturation and wettability.The interfacial area between the wetting and thenonwetting phases (brine and decane) in unconsolidatedporous media (glass beads) was measured using an anionicsurfactant (3-phenyl decyl benzene sulfonate) as aninterfacial tracer. The beads are water-wet; treating themwith organosilane rendered them oil-wet. The measurementswere done at a series of steady-state fractional flows,providing data at intermediate as well as residual saturations.Flow rates were kept low so that capillary forces controlledthe fluid configurations. We observe significant differencesin interfacial areas as a function of wetting-phase saturationas the wettability is changed from water-wet to oil-wet.During primary drainage, measured interfacial area increasesmonotonically with decreasing water saturation in a water-wet medium. In contrast, the interfacial area measuredin the oil-wet porous medium increases with decreasingdecane saturation, reaches a maximum, and decreases asthe residual decane saturation is achieved. The oil-wetexperiment is qualitatively consistent with theoretical resultsthat predict the existence of a maximum in fluid-fluidinterfacial area during drainage. The water-wet experimentis consistent with theoretical predictions that include thearea of grains in pores that have been drained. We concludethat, in the water-wet experiments, the tracer adsorbs atthe interface between the nonwetting phase and the wettingfilms on grains. In the oil-wet experiments, either the oilfilms are not sustained at high water saturation or the tracerdoes not adsorb at them, possibly prevented by sterichindrance. Interpretation of interfacial tracer experimentstherefore requires care: for some mass transportprocesses, the thin films of wetting phase on grains willnot behave the same as macroscopic volumes of wettingphase.