A new temperature-resistant and fast dissolving nano-silica/poly (AM-AMPS) composite drag reducer for slickwater fracturing

Polyacrylamide-based drag reducers are an essential component of slickwater fracturing fluids and are used to reduce friction during the fracturing process. However, the elevated temperature accelerates the mechanical and oxidative degradation of polyacrylamide, resulting in a dramatic decrease in the drag reduction capability. To improve the temperature resistance of polyacrylamide, many researchers have focused on introducing rigid groups into the side chains of polyacrylamide. However, the improvement in the temperature resistance of polyacrylamide is limited. To address this problem, a novel water-in-water nanocomposite drag reducer, called ANS-PAA, was developed. ANS-PAA was synthesized by in-situ dispersion polymerization, which involved the use of amino-functionalized nano-silica, acrylamide, and 2-acrylamido-2-methylpropane sulfonic acid. The nanoparticles were linked to the polymer through hydrogen bonding and electrostatic interactions, which dramatically improved the thermal stability of ANS-PAA molecules. The drag reducer exhibits fast dissolving and strong temperature-resistant. Its dissolution time in tap water is 19 s and its drag reduction rate at 120 °C is 70.2 %. In addition, the nanoparticles embedded in the polymer network enhanced the strength of the structure. This study provides valuable insights into the development of drag reducers in slickwater fracturing fluids that more efficiently handle the high temperatures encountered in deep oil and gas reservoirs.