Synthesis of modified silica nano as plugging agent for drilling fluid

There are a large number of nano-micron pores on the surface of the rock layer, and during the drilling process, water molecules will penetrate into the formation through these nano-micron pores, causing hydration and expansion of the rock, causing instability of the wellbore and other problems. Nano-micron plugging agents can effectively seal the nano-micron pores in the formation, reducing the hydration and expansion of the formation. This paper synthesized the ternary copolymer (AAK) using modified nano silica (KH-570), acrylamide (AM), and 2-acrylamide-2-methyl-1-propane sulfonic acid (AMPS) as raw materials, and used it as a plugging agent in water-based drilling fluids. The characterization and performance of AAK were studied using Fourier transform infrared spectroscopy, particle size analyzer, transmission electron microscopy, and thermogravimetric experiments. The plugging performance was evaluated using microporous filter membrane temperature and pressure tests, liner swelling tests, immersion test, and contact angle tests. In addition, its tackiness and salt resistance were also tested. The results indicate that the particles of AAK are nanoscale particles, which can effectively seal the nano and micro pores in rock blocks. At the same time, AAK has good temperature and salt resistance. The addition of AAK does not significantly change the rheological properties of the drilling fluid and can be used as a plugging agent in water-based drilling fluids.