| 摘要 |
The application discloses a viscous aqueous alkaline drilling liquid (fluid) essentially free of clays, for drilling subterranean wells, and a method of drilling such wells. The fluid is circulated into and out of the well, to flush out drill cuttings. The alkaline composition comprises a combination of the thickeners (a) 10 to 90 parts by weight of an addition polymer of an unsaturated carboxylic acid, preferably in the form of a copolymer with another ethylenically unsaturated monomer, for example a copolymer of a major amount of methacrylic acid and a minor amount of ethyl acrylate, the polymer having a molecular weight of from 125,000 to 12,000,000 solubilized in the aqueous system by an alkali such as sodium carbonate, and (b) 10 to 90 parts by weight of a water soluble polysaccharide, or a water soluble derivative thereof ("polysaccharide" being used herein in a generic sense to include such derivatives) such as hydroxyethyl cellulose, the total amount of (a) plus (b) being 100 parts.
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