Experimental and COSMO-RS Simulation Studies on the Effects of Polyatomic Anions on Clay Swelling

Abstract

Ionic liquids (ILs) can play a vital role in clay swelling inhibition during hydraulic fracturing. Previous studies highlighted the effect of side-chain length attached to the cationic core and different anions possessing almost the same chemical properties on inhibition performance. However, polyatomic anions have the potential to superiorly inhibit swelling compared to monoatomic anions. In this study, three ILs, namely, 1-butyl-3-methylimidazolium chloride (BMIMCl), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), were utilized to assess the effects of polyatomic anions on clay swelling inhibition. These performances were compared with the performances of a conventional inhibitor, potassium chloride (KCl). X-ray diffraction (XRD) testing was applied to check the mineral components present in the bentonite clay sample studied in this research. Clay swelling inhibition performance and rheological properties of these ILs were evaluated by the bentonite plate soaking test, linear swelling test, and rheological test. The swelling inhibition mechanisms were investigated through ζ-potential measurement, Fourier transform infrared (FT-IR) spectroscopy, and contact angle measurement. Moreover, COSMO-RS computer simulation was conducted to explain the inhibition mechanisms theoretically. The results demonstrated that BMIMPF6 showed superior inhibition performance and reduced the swelling by 21.55%, while only 9.26% reduction was attained by potassium chloride (KCl). The adsorption ability on the bentonite surface through electrostatic attraction, higher activity coefficient, and less electronegativity of PF6 – anion played a vital role in attaining such superior inhibition performance by BMIMPF6.

Recent Advances in Deep Eutectic Solvents as Shale Swelling Inhibitors: A Comprehensive Review

“…The success of fracturing processes is determined by the quality of induced fracture networks as well as the after effects. 17 The success and after effects of horizontal drilling and hydraulic fracturing are mostly influenced by the drilling and fracturing fluids. The drilling or fracturing fluids can be of different types such as oil-based fluids and water-based fluids.…”

“…Hydraulic fracturing is applied to expand the connectivity of the pores in the shale formation. The success of fracturing processes is determined by the quality of induced fracture networks as well as the after effects . The success and after effects of horizontal drilling and hydraulic fracturing are mostly influenced by the drilling and fracturing fluids.…”

“…The success of fracturing processes is determined by the quality of induced fracture networks as well as the after effects. 17 molecules and allow water to adsorb on the interlayer gap. 18−20 Swelling of clay can obstruct shale gas production by causing a slew of issues such as particle buildup in the mud, hole collapse, tight holes, drill pipe sticking, pore plugging, reduced permeability, and so on.…”

Effects of imidazolium- and ammonium-based ionic liquids on clay swelling: experimental and simulation approach

“…Recent approaches are focusing on non-conventional inhibitors such as nanoparticles (Lara et al 2017;Saleh and Ibrahim 2019;Yekeen et al 2019), saccharides and their derivatives (Ma et al 2019;Ismail and Ann 2009), bio-surfactants (Aggrey et al 2019), and ionic liquids (ILs) (Rahman et al 2020a(Rahman et al , 2021. ILs are liquid organic salts composing of anions and cations along with substituents attached to the cation (Berry et al 2008;Bubalo et al 2014).…”

“…The reason behind these similar inhibition performances is that these anions possess almost similar types of molecular properties. Rahman et al (2021) investigated the effects of polyatomic anions on clay swelling inhibition and discovered that less electronegative polyatomic anions perform better (Rahman et al 2021). Yang et al (2019) investigated the effects of the alkyl side chain attached to the imidazolium cation and suggested that a short alkyl chain exhibited better inhibition performance (Yang et al 2019).…”