Patent ID: 9365762
Filing Date: 2016-06-14
CPC Classification: C09K

Claim Text:
1. A shear strength improving agent for water-in-oil emulsion drilling fluids comprising a dimer acid-organic amine copolymer, which comprises structural units from dimer acid, structural units from alkyl amine, and structural units from aromatic amine, wherein the dimer acid is a dimer of oleic acid and linoleic acid, the alkyl amine is one or more of C10-C20 alkyl primary amines, and the aromatic amine is one or more of aniline and aniline with one or more sites on the benzene ring substituted by C1-C3 alkyl, wherein based on the total weight of the shear strength improving agent for water-in-oil emulsion drilling fluids, the copolymer is present in an amount of 50-70 wt. %.