DRILLING MUD Russian patent published in 1998 - IPC

FIELD: drilling of oil and gas wells. SUBSTANCE: drilling mud comprises (wt %): 5.0-10.0 clay: 3.0-5.0 viscosity reducer; water loss reducer; 0.5-1.0 potassium hydroxide; 1.0-2.0 dust of cement roasting furnaces; 20.0-40.0 bed brine of Iren level; and the water balance. Said technical solution does not employ deficient potassium containing salts and makes it possible to maintain stable pH value during drilling out terrigenous deposits with salt interlayers, and promotes higher technical and economic indices of drilling operation due to prevention of dispersion and hydration of clay rocks, greater mechanical strength and deeper penetration to reach gold. EFFECT: improved properties of the drilling mud. 2 tbl