Imidazolium-Based Ionic Liquids as Clay Swelling Inhibitors: Mechanism, Performance Evaluation, and Effect of Different Anions

Abstract

Clay swelling is one of the challenges faced by the oil industry. Water-based drilling fluids (WBDF) are commonly used in drilling operations. The selection of WBDF depends on its performance to improve rheology, hydration properties, and fluid loss control. However, WBDF may result in clay swelling in shale formations during drilling. In this work, the impact of imidazolium-based ionic liquids on the clay swelling was investigated. The studied ionic liquids have a common cation group, 1-allyl-3-methyllimidozium, but differ in anions (bromide, iodide, chloride, and dicyanamide). The inhibition behavior of ionic liquids was assessed by linear swell test, inhibition test, capillary suction test, rheology, filtration, contact angle measurement, scanning electron microscopy, and X-ray diffraction (XRD). It was observed that the ionic liquids with different anions reduced the clay swelling. Ionic liquids having a dicyanamide anion showed slightly better swelling inhibition performance compared to other inhibitors. Scanning electron microscopy images showed the water tendency to damage the clay structure, displaying asymmetrical cavities and sharp edges. Nevertheless, the addition of an ionic liquid to sodium bentonite (clay) exhibited fewer cavities and a smooth and dense surface. XRD results showed the increase in d-spacing, demonstrating the intercalation of ionic liquids in interlayers of clay. The results showed that the clay swelling does not strongly depend on the type of anion in imidazolium-based ILs. However, the type of anion in imidazolium-based ILs influences the rheological properties. The performance of ionic liquids was compared with that of the commonly used clay inhibitor (sodium silicate) in the oil and gas industry. ILs showed improved performance compared to sodium silicate. The studied ionic liquids can be an attractive alternative for commercial clay inhibitors as their impact on the other properties of the drilling fluids was less compared to commercial inhibitors.

Ionic liquids as alternative solvents for energy conservation and environmental engineering

“…The filtrate fluid's charge and electrolytic properties can be efficiently controlled by the clay stabilizers and the clay platelets can be held in place. Imidazolium-based ionic liquids have been identified as a possible inhibitor of clay swelling and research in this area is progressing at a brisk pace [21]. Shale oil is the unconventional oil extracted from a class of fine-grained classic sedimentary rocks known as shale rocks.…”

Ionic Liquids as Clay Swelling Inhibitors: Adsorption Study

“…ILs have gained a lot of attention in the last few decades because of interesting characteristics, such as low vapor pressure, specific solvating ability, high thermal stability, compatibility with inorganic, organic, and polymeric materials, and so forth. , Because of excellent characteristics, ILs have found many industrial applications, including nanocomposite preparation, dye adsorption, catalysis, gas separation, green solvents, and so forth. − In recent years, ILs have been employed for many oil and gas applications. Numerous researchers have studied the use of ILs in drilling/completion fluids and enhanced oil recovery (EOR). − …”

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

“…These segments of the ILs have distinguished effects on clay swelling inhibition mechanisms. Ahmed Khan et al (2020) studied the effects of halogen group anions and reported that there is negligible difference in their inhibition performances due to different halides (Ahmed Khan et al 2020). The reason behind these similar inhibition performances is that these anions possess almost similar types of molecular properties.…”