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The Effect of the Surfactant on the Migration and Distribution of Immiscible Fluids in Pore Network
계면활성제가 공극 구조 내 비혼성 유체의 거동과 분포에 미치는 영향
Econ. Environ. Geol. 2021 Feb;54(1):105-15
Published online February 28, 2021;
Copyright © 2021 the Korean society of economic and environmental gelology.

Gyuryeong Park, Seon-Ok Kim, Sookyun Wang*
박규령 · 김선옥 · 왕수균*

Department of Energy Resources Engineering, Pukyong National University, Busan 48513, Korea
부경대학교 에너지자원공학과
Received January 4, 2021; Revised February 3, 2021; Accepted February 5, 2021.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
The geological CO2 sequestration in underground geological formation such as deep saline aquifers and depleted hydrocarbon reservoirs is one of the most promising options for reducing the atmospheric CO2 emissions. The process in geological CO2 sequestration involves injection of supercritical CO2 (scCO2) into porous media saturated with pore water and initiates CO2 flooding with immiscible displacement. The CO2 migration and distribution, and, consequently, the displacement efficiency is governed by the interaction of fluids. Especially, the viscous force and capillary force are controlled by geological formation conditions and injection conditions. This study aimed to estimate the effects of surfactant on interfacial tension between the immiscible fluids, scCO2 and porewater, under high pressure and high temperature conditions by using a pair of proxy fluids under standard conditions through pendant drop method. It also aimed to observe migration and distribution patterns of the immiscible fluids and estimate the effects of surfactant concentrations on the displacement efficiency of scCO2. Micromodel experiments were conducted by applying n-hexane and deionized water as proxy fluids for scCO2 and porewater. In order to quantitatively analyze the immiscible displacement phenomena by n-hexane injection in pore network, the images of migration and distribution pattern of the two fluids are acquired through a imaging system. The experimental results revealed that the addition of surfactants sharply reduces the interfacial tension between hexane and deionized water at low concentrations and approaches a constant value as the concentration increases. Also it was found that, by directly affecting the flow path of the flooding fluid at the pore scale in the porous medium, the surfactant showed the identical effect on the displacement efficiency of nhexane at equilibrium state. The experimental observation results could provide important fundamental information on immiscible displacement of fluids in porous media and suggest the potential to improve the displacement efficiency of scCO2 by using surfactants.
Keywords : geological CO2 sequestration, immiscible displacement, surfactant, micromodel, displacement efficiency


February 2021, 54 (1)