Modification and performance evaluation of Konjac gum in drilling fluid

Abstract

Abstract Because of the rock carrying property of drilling fluid, it is usually necessary to add bentonite and polymer into the drilling fluid to improve the viscosity of the drilling fluid. However, bentonite and polymer will seriously affect the rheological property, sand carrying property, drilling speed, degassing effect, etc. of the drilling fluid. Therefore, it is necessary to develop a new environment-friendly low viscosity cutting agent for drilling fluid. In this paper, konjac gum was modified by metal complexation. Some modified konjac gum were studied. The effects of different dosages of modified konjac gum on the rheological properties of drilling fluid were analyzed through infrared spectrum characterization, thermogravimetric analysis and compatibility evaluation. The experiment proved that heavy metal cations and inorganic flocculant polyaluminum chloride/iron can coordinate with konjac gum, to form a cation konjac glucomannan chelate system, which enhances the three-dimensional network structure of the molecule; The shielding effect of metal cations will weaken the electrostatic repulsion between -O- in konjac glucomannan and compete with each other, thus affecting the rheological properties. The modified konjac gum not only improves the rheological property of its aqueous solution but also improves its water solubility. The operation process is simple and green.