Synthesis and application of sodium 2-acrylamido-2-methylpropane sulphonate/N-vinylcaprolactam/divinyl benzene as a high-performance viscosifier in water-based drilling fluid

• Published in: Journal of applied polymer science 2016-11, Vol.133 (43), p.np-n/a
• Main Authors: Xie, Binqiang, Liu, Xiaodong, Wang, Huiqiang, Zheng, Lihui
• Format: Article
• Language: English
• Subjects: applications; Bentonite; Brines; Chemical analysis; Copolymers; Crosslinking; Divinylbenzene; Drilling fluids; Fluids; functionalization of polymers; Gravimetric analysis; Infrared analysis; Materials science; Molecular structure; morphology; NMR; Nuclear magnetic resonance; Optimization; Polymerization; Polymers; Rheological properties; Rheology; Shear tests; Shear thinning (liquids); Sodium; Sulfonates; Thermal resistance; Thickening; Xanthan
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.44140

ABSTRACT Aiming at good thickening ability and temperature resistance in water‐based drilling fluid, a novel copolymer viscosifier (SDKP) of sodium 2‐acrylamido‐2‐methylpropane sulfonate (NaAMPS) with N‐vinylcaprolactam (NVCL) and cross‐linking divinylbenzene (DVB) was prepared by micellar radical polymerization. The composition and molecular structure of optimal SDKP under the optimum reaction conditions was characterized by FT‐IR, 1H‐NMR, and elemental analysis, and the molecular weight was determined by GPC. Thermal gravimetric analysis showed that the SDKP was even stable when the temperature was not higher than 330 °C. The performance of SDKP as viscosifier for aqueous, brines, and saturated brine bentonite drilling fluid was evaluated before and after aging tests at 230 °C for 16 h. The evaluation results indicated that the SDKP had excellent thickening ability, thermal resistant, and salt tolerance. HTHP rheology test showed that the SDKP containing drilling fluids displayed a thermo‐thickening effect in temperature range of 150 to 180 °C, which was beneficial to increase the viscosity and strength of fluids at high temperatures. Shear test showed that the SDKP illustrated a similar shear thinning to xanthan gum. ESEM observations demonstrated that the continuous three‐dimensional network was formed in the SDKP aqueous and brines solution, which was probably the main reason for its excellent thickening properties. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 44140.