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Title: Drilling fluids

Patent ·
OSTI ID:5310287

A method is described of preparing a composition suitable for use as a drilling fluid comprising the steps of: (a) copolymerizing a hydrophilic vinyl monomer selected from the group consisting of acrylic acid, methacrylic acid, other related monomers and mixtures and any two or more thereof with at least one hydrophobic vinyl monomer selected from the group consisting of acrylic acid esters, methacrylic acid esters, vinyl esters of saturated monocarboxylic acids having from 1 to 3 carbon atoms, and combinations of any two or more thereof under polymerization conditions in an inert low chain transfer organic liquid medium selected from the group consisting of n-hexane, cyclohexane and chlorofluorocarbons at a polymerization temperature and for a period of polymerization time sufficient to produce a copolymer having a weight average molecular weight in the range from about 100,000 to about 500,000; (b) contacting the resulting copolymer in the inert, low chain transfer, organic liquid medium selected from the group consisting of n-hexane, cyclohexane and chlorofluorocarbons with an aqueous solution of sodium hydroxide which is present in a quantity sufficient to raise the pH of the subsequently dried copolymer salt in the polymer solution in water of at least about 1 weight percent in concentration to a value in the range from about 5.3 to about 12 to produce the salt form of the resulting copolymer; (c) drying the salt form of the resulting copolymer produced by step (b) to produce a dried copolymer salt; (d) adding a quantity of the dried copolymer salt produced in accordance with step (c) to a quantity of a mixture comprising water and a clay substance suspended in the water; and (e) mixing the dried copolymer salt, the water and the clay substance to produce a drilling fluid.

Assignee:
Phillips Petroleum Co., Bartlesville, OK
Patent Number(s):
US 4604216
OSTI ID:
5310287
Resource Relation:
Patent File Date: Filed date 11 Jun 1984
Country of Publication:
United States
Language:
English