pH and ionic liquids impacts on SiO2-nanoparticles for surface phenomena modifications for heavy acidic crude oil

Abstract

AbstractThe current study is designed and performed to examine the impact of a combinative method including the new class of surfactants from the ionic liquids (ILs) family (imidazolium type) and nanoparticles (NPs) namely silicon dioxide nanoparticles (SiO2-NPs). Besides, the effect of pH concomitant with the other parameters was examined since pH is an essential operating parameter especially if researchers dealing with a non-neutral type of crude oil. Unfortunately, although using chemicals is highly effective, there are limited investigations dealing with a new class of surfactants, NPs, and operating conditions such as pH. In other words, although there are several investigations dealing with alkaline, polymers, and surfactants, a few studies were performed to find the interactions between the new class of surfactants such as ILs, NPs (no matter metallic-based or nonmetallic-based type) and pH which can directly manipulate the in-situ surfactant formation which acts similarly to alkaline injection. In this way, two different surfactants namely 1-dodecyl-3-methyl imidazolium chloride ([C12mim][Cl]), and 1-octadecyl-3-methyl imidazolium chloride ([C18mim][Cl]) and SiO2-NPs with concentrations of 0–2000 ppm and 0–1000 ppm are used for interfacial tension (IFT) and wettability alteration investigations using heavy acidic crude oil. The measured IFT values revealed that increasing the surfactant concentration to 2000 ppm can reduce the IFT to the minimum value of 0.94 and 0.88 mN/m for [C12mim][C] and [C18mim][Cl], respectively. Besides, the measurements revealed that it is possible to reach the water-wet condition with contact angles of 81.3° and 74.5° for [C12mim][Cl] and [C18mim][Cl], respectively. Moreover, the measurements revealed that increasing the pH from 3 to 11 has a considerable effect on the IFT reduction and wettability alteration because of in-situ surfactant formation (reaction between the OH− and the functional group of the crude oil) which can act as a solution including alkaline in it. Finally, the IFT and contact angle were measured using 1000 and 500 ppm of [C12mim][Cl] and [C18mim][Cl] while the pH and SiO2-NPs concentrations ranged between 3–11 and 0–1000 ppm, respectively. The measurements revealed the significant impact of SiO2-NPs for reducing the IFT and changing the wetness of the rock surface with a minimum IFT value of 0.35 mN/m and contact angle of 23.3° (strongly water-wet condition). Considering the obtained results, it can be concluded that the proposed combinative method is highly applicable for higher oil production using the lab-scale equipment. The point is that the further systematic investigations are required since using combinative methods for enhanced oil recovery (EOR) purposes are still in the preliminary stages of their appearance.