▎ 摘　　要

NOVELTY - Oil-based drilling fluid comprises 100 pts. wt. white oil, 3-6 pts. wt. organic soil, 10- 22 pts. wt. calcium chloride solution, 1-4 pts. wt. emulsifying agent, 2-6 pts. wt. wetting agent, 2-7 pts. wt. calcium oxide, 5-20 pts. wt. blocking agent, 5-15 pts. wt. weighting agent and 2-6 pts. wt. fluid loss reducing agent. USE - The fluid is useful in the field of petrochemical industry. ADVANTAGE - The fluid reduces the probability of invading the micro crack by contacting with the active shale; avoid the micro-crack breaking well wall and is conducive to the stability of the well wall. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing oil-based drilling fluid comprising adding emulsifying agent, wetting agent, calcium chloride solution, calcium oxide, organic soil in white oil to prepare base slurry and mixing the base slurry, blocking agent, weighing agent and reducing fluid loss reducing agent to obtain the oil-based drilling fluid.