Performance evaluation of polymer nanolatex particles as fluid loss control additive in water-based drilling fluids

Abstract

The development of various nanoparticles and their successful application in oil and gas drilling engineering is an extremely interesting and crucial area of research, particularly in the field of drilling fluids. In this study, styrene, butyl acrylate, acrylamide, and 2-acrylamide-2-methylpropanesulfonic acid were used as the main raw materials to synthesize a polymer nanolatex (SBAA) employing a conventional emulsion polymerization approach (one-pot method). SEM, TEM, and PSD experiments demonstrated that SBAA is a nanoparticle with a particle size of around 150 nm and a distinct core-shell structure. The TGA analysis revealed that SBAA had a decomposition temperature of 296 °C. Particularly, the unique self-assembly behavior of nanolatex particles is discussed for the first time using TEM and UV–Vis experiments. Additionally, filtration and permeability plugging tests were used to evaluate the filter loss reduction and micro-pore plugging ability of the SBAA in water-based drilling fluids. The findings showed that SBAA could reduce the medium pressure filtration loss by around 33% compared with the basic bentonite fluid, and the reduction rate after aging at 200 °C is around 41%. Particularly, it can reduce the filtrate loss velocity of water-based drilling fluid in heterogeneous pores, and the effects of filtration reduction and mud cake quality enhancement outperform those of commercial nanosilica particles. This study offers a novel reference approach for developing novel nanomaterials for water-based mud to plug microscopic pores and maintain wellbore stability.