▎ 摘　　要

NOVELTY - Drilling fluid comprises water, bentonite, sodium carbonate, fluid loss reducer, anti-slump agent, lubricant, and plugging agent. USE - Drilling fluid. ADVANTAGE - The drilling fluid has a pH of 8.5-9.5 and a density of 1-2 g/cm3. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing , which involves adding bentonite and sodium carbonate successively in water, mixing and leaving standstill to obtain pre-hydrated bentonite slurry, adding fluid loss reducer, anti-slump agent, lubricant and plugging agent in sequence to the pre-hydrated bentonite slurry, adjusting the pH value to 8.5-9.5, and optionally adding a weighting agent to adjust the density to 1-2 g/cm3 to obtain the drilling fluid.