Drilling fluid composition
AssigneeGeorgia-Pacific Corporation
InventorJack R. Kelley
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Abstract
A water-based drilling fluid composition is described which comprises an aqueous dispersion of a clay material containing an effective dispersing amount of a modified lignosulfonate which is obtained by graft polymerization of from 5 to 30 weight percent of an acrylic compound with the lignosulfonate. The grafted lignosulfonate has an average molecular weight of less than 80,000.
Claims19
A water-base drilling fluid comprising a suspension of clay material and an effective dispersing amount of a water-soluble graft copolymer which is the reaction product of lignosulfonate and an acrylic compound selected from the group consisting of acrylic acid, acrylonitrile, acrylamide, and esters of alcohols of one or two carbon atoms and acrylic acid, said reaction product being prepared by reacting lignosulfonate with from 5 to 30 weight percent said acrylic compound at a pH below 6 using a free radical initiator, said reaction product having an average molecular weight not exceeding about 80,000.
Dependencies are inferred from the claim text.