Dioctyl Glyceryl Ether Ethoxylates as Surfactants for Surfactant–Polymer Flooding

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• 作者：Limin Yan ; Zhenggang Cui ; Binglei Song ; Xiaomei Pei ; Jianzhong Jiang
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：July 21, 2016
• 年：2016
• 卷：30
• 期：7
• 页码：5425-5431
• 全文大小：360K
• 年卷期：0
• ISSN：1520-5029

文摘

Enhanced oil recovery by chemical flooding has been a main measure for postponing the overall decline of crude oil output in China, and surfactant–polymer (SP) flooding may replace alkali–surfactant–polymer flooding in the future for avoiding the undesired effects of using caustic alkali. In this paper, a series of double alkyl non-ionic surfactants, 1,3-dioctyl glyceryl ether ethoxylates (diC₈GE-E_n, where n = 4.6–15.8), were synthesized and characterized and the effects of the ethylene oxide (EO) number on their properties were evaluated. The results show that diC₈GE-E_n are highly surface-active, as reflected by their low critical micelle concentration (cmc) (<2 × 10^–5 mol/L) and low γ_cmc (<30 mN/m). Specifically, the member with the shortest EO chain (diC₈GE-E_4.6), which gives a saturated adsorption (5.81 × 10^–10 mol/cm²) nearly double that of others (2.94–2.63 × 10^–10 mol/cm²) at the air/water interface, can reduce Daqing crude oil/connate water interfacial tension (IFT) to ultralow (<0.01 mN/m) solely at 5 mM at 45 °C. The members with larger EO numbers, although cannot reduce Daqing crude oil/connate water IFT to ultralow solely, are very good hydrophilic components superior to a typical monoalkyl non-ionic surfactant, such as polyoxyethylene (10) monododecyl ether (C₁₂E₁₀), when mixed with a hydrophobic surfactant, didodecyl methyl hydroxylpropyl sulfobetaine (diC₁₂HSB), for SP flooding free of alkali. At optimum formulation, the molar fraction of diC₈GE-E_n can be decreased from 0.85 to 0.45 with increasing n from 8.0 to 15.8 and ultralow IFT can be easily achieved at a wide effective concentration range (0.3–10 mM) thanks to the larger interaction of the double alkyl chains in the molecules with the oil. Derived from commercially available materials and produced by commercially realizable technology, these surfactants are therefore practically significant for SP flooding.