Study on rheological properties of montmorillonite drilling fluid under different influencing factors

Abstract

The exploitation and utilization of geothermal resources is a major research work in earth science and the energy industry. It is of great significance to solve the increasingly severe energy shortage and global environmental problems. In view of the complex drilling conditions of geothermal drilling, it is of great scientific significance and engineering practical value to understand the rheological properties of montmorillonite as drilling fluid base slurry under different conditions. In this paper, the effect of montmorillonite as a base slurry of drilling fluid on the rheological property at different temperatures, pH, and salt concentrations was studied through a lot of experiments. The experimental results show that the influence of high temperature on the rheological properties of base slurry is complex, mainly affecting the clay structure, resulting in high-temperature thickening, thinning, and curing of montmorillonite. Proper pH value can improve the rheological property of drilling fluid. Keeping the pH in the 9-10 range reduces plastic viscosity and helps maintain drilling operations. Adding electrolyte to montmorillonite suspension, Na+ and K+ in the electrolyte will press the counter-ions in the diffusion layer into the adsorption layer, so that the charge of montmorillonite is reduced and particles are easy to gather.