摘要 |
The invention relates to an aqueous drilling fluid composition, a filtration control agent for utilization in said aqueous drilling fluid, and a method of forming a filter cake on the wall of a well for the reduction of filtrate from said drilling fluid, by utilization of a copolymer of: (1) a (meth) acrylamido alkyl sulfonic acid or alkali metal salt thereof; and (2) N, N-dialkyl (meth) acrylamide. The copolymer may be cross-linked with N,N'-methylenebisacrylamide or other appropriate cross-linking agent.
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