Abstract:In order to improve the temperature and salt resistance as well as environmental performance of water-based drilling fluid thickening agents, and meet the needs of shale oil drilling construction, an environmentally friendly temperature and salt resistant thickening agent HBZ-2 was prepared using methacrylamide (MAA), N-vinyl pyrrolidone (NVP), and polymerizable quaternary ammonium salt cationic monomer (H-12) as raw materials. The molecular structure of the thickening agent HBZ-2 was characterized indoors, its mechanism of action was analyzed, and its thickening performance, temperature and salt resistance, environmental performance, and basic performance of drilling fluid were investigated. The results showed that under the same experimental conditions, the environmentally friendly temperature and salt resistant thickening agent HBZ-2 had better thickening performance, temperature resistance, and salt resistance than the same type of thickening agents HE300 and 80A51. When the dosage of the thickening agent HBZ-2 is 1%, after high-temperature aging at 200 ℃, the viscosity of the seawater slurry can still reach over 30mPa · s after adding 20% sodium chloride or 5% calcium chloride, indicating strong temperature and salt resistance. The basic performance of the drilling fluid system with the addition of viscosity enhancer HBZ-2 after high-temperature aging is relatively stable. In addition, the viscosity enhancer HBZ-2 has low biological toxicity, good biodegradability, and does not contain heavy metals, with excellent environmental performance. The research results indicate that the environmentally friendly temperature and salt resistant thickening agent HBZ-2 has excellent performance and is suitable for application in offshore shale oil drilling wells with high environmental performance requirements.