still for the drilling of holes in the ground and at the drilling anvender a borrslamskomposition - mud and alkaline jordartsmetallhydroxid

摘要

1462551 Drilling fluids CONTINENTAL OIL CO 28 April 1975 [29 April 1974 (2)] 17606/75 Heading E1F A water base drilling mud comprises 5-35 pounds/barrel of clay; up to 5 pounds/barrel of an alkaline earth metal hydroxide selected from calcium hydroxide and mixtures of calcium hydroxide and other alkaline earth metal hydroxides, and/or up to 5 pounds/barrel of an alkali metal hydroxide, there being no more than 3 pounds/barrel of the alkali metal hydroxide when the alkaline earth metal hydroxide is present; and a monocalcium phosphate containing material selected from monocalcium phosphate and mixtures containing 40-60 weight per cent of monocalcium phosphate and 60-40 weight per cent of calcium sulphate, there being used at least a stoichiometric amount, based on the weight of the alkaline earth metal hydroxide and/or on the weight of the alkali metal hydroxide, of monocalcium phosphate. The mud may be a prehydrated bentonite and one of the alkaline earth metal hydroxides may be barium hydroxide. The monocalcium phosphate is present in an amount of 1-25 pounds/barrel and in a weight ratio with said alkaline earth metal hydroxide and/or alkali, metal hydroxides of from 1:1 to 5:1. The mud may contain 1-20 pounds/barrel of a mud thinner, e.g. ferrochromo lignosulphonates, lignins or tannins, and from 1-20 pounds/barrel of a fluid loss additive, e.g. starch, caustic treated starch, carboxymethyl cellulose, or mixtures thereof.