Various water-based drilling fluids are increasingly being used in oil and gas exploitation, for more environmentally acceptable and low-cost advantages than oil-based drilling fluids. In petroleum engineering, many shale inhibitors were also obtained or improved by introducing quaternary ammonium groups through the etherification reaction for the useful functionality and improved solubility in water. Quaternary ammonium modification, as a common modification method, has been widely studied to improve the antibacterial ability, thermal properties, and adhesive efficiency of materials.
Figure 1. Drilling diagram on the oil field
In generally, many quaternary ammonium compounds water-based drilling fluids form a protective layer of hydrated polymer retarding clay swelling by attaching or adsorbing onto clay particles. Here, take the 2,3-epoxypropyltrimethylammonium chloride (EPTAC, denoted as GT) for example, and its schematic diagram of inhibition mechanism was illustrated in figure 2. GT, containing polar hydroxyl, amino groups, and cationic quaternary ammonium groups, could be easily and strongly adsorbed on the clay particles through electrostatic attraction and hydrogen bonding. After adsorption, GT effectively decreased the potential of Na−bentonite (Na−BT) particles and suppressed the double electrical layers. Moreover, as a high-molecularweight biopolymer with cationic groups, GT strongly adsorbed on the external surface of Na−BT, encapsulated them, and effectively pinned the clay particles together. Therefore, GT prevented water ingress into clay and shale through an encapsulating effect.
Figure 2. Schematic diagram of the GT inhibition mechanism on clay hydration, swelling, and dispersion.
Compared with other water-based drilling fluids, quaternary ammonium water-based drilling fluids have the following advantages:
- Quaternary ammonium water-based drilling fluid is non-toxic and harmless, environmentally friendly, and has little pollution to the environment.
- Quaternary ammonium water-based drilling fluid has good inhibition behavior and good compatibility.
- Quaternary ammonium water-based drilling fluids show excellent results.
What Can Alfa Chemistry Do for You?
Alfa Chemistry has a professional team with many years of experience and has focused on the preparation and application of quaternary ammonium water-based drilling fluids. We are pleased to use our extensive experience and advanced platform to offer the most qualified products and the best service to satisfy each demand from our customers in quaternary ammonium water-based drilling fluids. If you want to know more about quaternary ammonium water-based drilling fluids, please contact us.
- Li X.; et al. Application of gelatin quaternary ammonium salt as an environmentally friendly shale inhibitor for water-based drilling fluids. Energy Fuels, 2019, 33(9): 9342-9350.