Synthesis and properties of acrylamide 2-acrylamido-2-methypropane sulfonic acid sodium styrene sulfonate N-vinyl pyrrolidone quadripolymer and its reduction of drilling fluid filtration at high temperature and high salinity

Abstract

Abstract Acrylamide (AM), 2-acrylamido-2-methypropane sulfonic acid, sodium styrene sulfonate (SSS), and N-vinyl pyrrolidone (NVP) monomers were copolymerized via a redox initiator system to synthesize a quadripolymer capable of reducing drilling fluid filtration. Fourier transform infrared spectroscopy (FT-IR) was used to determine the molecular structure of the product, confirming its successful synthesis. The effects of the copolymer on the properties and salt resistance of drilling fluid are discussed. The adsorption of the copolymer on bentonite was also studied using atomic force microscopy (AFM). The copolymer reduced the filtration of drilling fluids of various salinities before and after aging at 200°C; at room temperature, the copolymer was adsorbed uniformly across the bentonite surface at low concentration. As its concentration increased, the distributed polymer spread and connected to form a network. After aging for 16 h at 200°C, the copolymer could still adsorb to bentonite and maintained its network structure. Sodium ions induced the coalescence of the copolymer, damaging its network structure.