The graft copolymers of AMPS with acrylamide and starch, AMPS with acrylamide and N, N-dimethylacrylamide, and AMPS with humic acid and acrylamide all have good filtration loss reduction, temperature resistance, and salt resistance in freshwater drilling fluid, saline drilling fluid, saturated saline drilling fluid, and seawater drilling fluid.
The pollution caused by clay dispersion and other factors often leads to an increase in the viscosity of drilling fluid, and a viscosity reducer is needed to control the rheological properties of the drilling fluid. The most commonly used drilling fluid viscosity reducer is iron chromium lignosulfonate (FCLS). The ternary copolymer of AMPS with acrylic acid and methacrylic acid is used as a drilling fluid viscosity reducer instead of FCLS, which not only retains the good salt and temperature resistance of FCLS, but also overcomes the toxicity of FCLS. Research has shown that ternary copolymers have stronger resistance to high valence metal ions than binary copolymers.