Rahman Md Tauhidur, Negash Berihun Mamo, Idris Alamin, Miah Mohammad Islam, Biswas Kallol
Department of Petroleum Engineering, Shale Gas Research Group (SGRG), and Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 32610 Bandar Seri Iskandar, Perak Darul Ridzuan, Malaysia.
Department of Engineering and Chemical Sciences, Karlstad University, 65188 Karlstad, Sweden.
ACS Omega. 2021 Sep 28;6(40):26519-26532. doi: 10.1021/acsomega.1c03786. eCollection 2021 Oct 12.
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 (BMIMBF), and 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF), 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 BMIMPF 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 PF anion played a vital role in attaining such superior inhibition performance by BMIMPF.
离子液体（ILs）在水力压裂过程中抑制黏土膨胀方面可发挥至关重要的作用。先前的研究强调了连接到阳离子核心的侧链长度以及具有几乎相同化学性质的不同阴离子对抑制性能的影响。然而，与单原子阴离子相比，多原子阴离子具有更优异的抑制膨胀的潜力。在本研究中，使用了三种离子液体，即1-丁基-3-甲基咪唑氯盐（BMIMCl）、1-丁基-3-甲基咪唑四氟硼酸盐（BMIMBF）和1-丁基-3-甲基咪唑六氟磷酸盐（BMIMPF），来评估多原子阴离子对黏土膨胀抑制的影响。将这些性能与传统抑制剂氯化钾（KCl）的性能进行了比较。应用X射线衍射（XRD）测试来检查本研究中所研究的膨润土样品中存在的矿物成分。通过膨润土平板浸泡试验、线性膨胀试验和流变试验评估了这些离子液体的黏土膨胀抑制性能和流变性质。通过ζ电位测量、傅里叶变换红外（FT-IR）光谱和接触角测量研究了膨胀抑制机制。此外，还进行了COSMO-RS计算机模拟，从理论上解释抑制机制。结果表明，BMIMPF表现出优异的抑制性能，使膨胀降低了21.55%，而氯化钾（KCl）仅使膨胀降低了9.26%。PF⁻ 阴离子通过静电吸引在膨润土表面的吸附能力、较高的活度系数和较低的电负性在BMIMPF获得如此优异的抑制性能中起着至关重要的作用。
