Lingyan Gong1, Guangzhi Liao2, Huoxin Luan3, Quansheng Chen3, Xiaobin Nie3, Dong Liu4, Yujun Feng5. 1. Polymer Research Institute, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China. 2. PetroChina Exploration & Production Company, Beijing 100007, People's Republic of China. 3. Research Institute of Experiment and Detection, Xinjiang Oilfield Branch Company, PetroChina, Karamay 834000, People's Republic of China. 4. Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621000, People's Republic of China. 5. Polymer Research Institute, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China. Electronic address: yjfeng@scu.edu.cn.
Abstract
HYPOTHESIS: The current mechanism of surfactant enhanced oil recovery (EOR) mainly relies on forming middle-phase microemulsions to get ultra-low oil-water interfacial tension. However, residual oil can also be recovered using low concentration surfactant solutions without microemulsion formation, and the interaction between the surfactant solution and crude oil at very early contact has not been studied yet. We hypothesize micelle solubilization of oil as an alternative EOR mechanism. EXPERIMENTS: Sodium dodecylbenzenesulfonate (SDBS), anisole and 1-hexene were used as a model surfactant and model polar and nonpolar compounds in crude oil, respectively. The interaction between SDBS micelles and these two additives was investigated with dynamic light scattering, UV-Vis spectroscopy, 1H NMR spectroscopy, cryogenic transmission electron microscopy, confocal microscope and small angle neutron scattering. FINDINGS: SDBS micelles become larger upon increasing additive concentration to transfer into swollen micelles. 1-Hexene is localized in the micelle core, and retains the spherical micelle shape, while anisole resides in the palisade layer and weakens the electrostatic repulsions among surfactant headgroups, inducing a sphere-rod transition. No emulsion droplets were observed for 0.2 wt% SDBS solution until 1.5 wt% anisole or 1-hexene was introduced. These findings help understanding the role surfactant micelles in EOR and propose a new mechanism for surfactant EOR processes.
HYPOTHESIS: The current mechanism of surfactant enhanced oil recovery (EOR) mainly relies on forming middle-phase microemulsions to get ultra-low oil-water interfacial tension. However, residual oil can also be recovered using low concentration surfactant solutions without microemulsion formation, and the interaction between the surfactant solution and crude oil at very early contact has not been studied yet. We hypothesize micelle solubilization of oil as an alternative EOR mechanism. EXPERIMENTS: Sodium dodecylbenzenesulfonate (SDBS), anisole and 1-hexene were used as a model surfactant and model polar and nonpolar compounds in crude oil, respectively. The interaction between SDBS micelles and these two additives was investigated with dynamic light scattering, UV-Vis spectroscopy, 1H NMR spectroscopy, cryogenic transmission electron microscopy, confocal microscope and small angle neutron scattering. FINDINGS:SDBS micelles become larger upon increasing additive concentration to transfer into swollen micelles. 1-Hexene is localized in the micelle core, and retains the spherical micelle shape, while anisole resides in the palisade layer and weakens the electrostatic repulsions among surfactant headgroups, inducing a sphere-rod transition. No emulsion droplets were observed for 0.2 wt% SDBS solution until 1.5 wt% anisole or 1-hexene was introduced. These findings help understanding the role surfactant micelles in EOR and propose a new mechanism for surfactant EOR processes.
Authors: Sébastien Roland; Guillaume Miquelard-Garnier; Andrey V Shibaev; Anna L Aleshina; Alexis Chennevière; Olga Matsarskaia; Cyrille Sollogoub; Olga E Philippova; Ilias Iliopoulos Journal: Polymers (Basel) Date: 2021-12-04 Impact factor: 4.329