Mechanistic Investigation of the Synergy of a Wide Range of Salinities and Ionic Liquids for Enhanced Oil Recovery: Fluid–Fluid Interactions

Abstract

In this paper, the performance of three imidazolium-based ionic liquids (ILs) including 1-hexyl-3-methylimidazolium chloride ([HMIM][Cl] or IL6), 1-octyl-3-methylimidazolium chloride ([OMIM][Cl] or IL8), and 1dodecyl-3-methylimidazolium chloride ([DMIM][Cl] or IL12) in reducing the interfacial tension (IFT) between crude oil and IL solutions was analyzed for the first time under a wide range of salinities (1000 to 195 476 ppm) at a reservoir temperature of 80 °C. The purpose was to microscopically analyze the occurring phenomenon at the fluid−fluid interface to determine the mechanism leading to oil extraction and to address the existing ambiguities in the literature concerning the synergism between ILs and different types/concentrations of ions. The quality of the synthesized ILs and their accumulation at the crude oil/IL solution interface was analyzed via attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, the IFT between crude oil and IL solutions was measured by the pendant drop method, and the micelles' size distribution and molecular diffusivity of the ILs in the aqueous solution was measured by the dynamic light scattering (DLS) technique. On the basis of the ATR-FTIR and IFT results, the accumulation of the ILs molecules at the interface of the crude oil/IL solution was a function of alkyl chain length and the ionic strength (IS) of solution; the longer alkyl chain ILs (i.e., IL12 in this study) accumulated more at the interface of the solution with more IS, leading to a more IFT reduction. At a constant but low range of salinities, the longer alkyl chain IL exhibited a lower IFT value in the presence of diluted seawater (dSW) than the diluted formation water (dFW). This is because of the higher concentration of divalent cations (Mg 2+ and Ca 2+ ) in dSW than dFW and their interactions with resin and asphaltene molecules and the salting-in effect mechanism that overcomes the lower saponification ability of dSW than dFW.

n-C7 Asphaltenes Characterization as Surfactants and Polar Oil from the HLDN Model Perspective

“…Nevertheless, the low stability of the O/W emulsions obtained in this work could be due to several factors, such as (i) little amount of asphaltenes adsorbed at the oil–brine interface ( C A < CNAC), (ii) repulsion–attractive interactions produced by the asphaltene polar groups and aromatic rings oriented toward the aqueous phase, , (iii) large droplet size of the dispersed phase (oil) due to several variables, such as the concentration and type of salt (NaCl) in the brine , and the energy applied during the emulsification process. …”

“…(iii) large droplet size of the dispersed phase (oil) due to several variables, such as the concentration and type of salt (NaCl) in the brine , and the energy applied during the emulsification process.…”

Upgrading the Properties of the Crude Oil–Water System for EOR with Simultaneous Effects of a Homologous Series of NanoGemini Surface-Active Ionic Liquids, Electrolytes, and pH

“…The strong electrostatic repulsion between head groups causes the orientation of the GSAILs to not find closed packed orientations at the crude oil–water interface. However, the anion of electrolytes (here Cl – ) weakens this interaction, leading to tight packing. , It means the electrical double layer surrounding the head group of GSAILs would be compressed. , The arrangement is schematically presented in Figure .…”

“…However, the anion of electrolytes (here Cl – ) weakens this interaction, leading to tight packing. 28 , 34 It means the electrical double layer surrounding the head group of GSAILs would be compressed. 11 , 23 The arrangement is schematically presented in Figure 4 .…”

Review on Potential Application of Saponin-Based Natural Surfactants for Green Chemical Enhanced Oil Recovery: Perspectives and Progresses

“…Several researchers have investigated the effect of salinity on IFT and have established that a change in IFT depends on the nature and type of ions resulting from the dissolution of salts. − Seven different salts were tested to further minimize the interfacial tension (IFT) between oil and water . The highest IFT reduction (from 1.07 to 0.838 mN/m) and minimum contact angle (39.67°) were achieved for Anabasis setifera –K 2 SO 4 .…”