This invention relates to the field of oil and gas technology, specifically to a broad-spectrum, high-seal oil-based
drilling fluid, comprising, by weight, 85-90 parts
base oil, 15-10 parts
calcium chloride brine, 3-5 parts primary emulsifier, 1.5-3 parts secondary emulsifier, 3-5 parts
calcium oxide, 3-5 parts
viscosity modifier, 3-5 parts
filtration reducer, 1-3 parts plastic plugging agent, 1-3 parts rigid plugging agent, 1-2 parts micron plugging agent, 1-2 parts nano plugging agent, and 200-300 parts
inert weighting agent. In this broad-spectrum, high-seal oil-based
drilling fluid, plugging agents of different particle sizes, hardnesses, and properties are used in combination to improve the sealing ability of the oil-based
drilling fluid. Among them, plastic plugging agents, rigid plugging agents, micron plugging agents, and nano plugging agents work synergistically to prevent
pressure transmission and reduce mud intrusion through
particle size distribution, bridging and filling, and film formation, thereby achieving the effect of sealing and preventing collapse.