Patent ID: 9745501
Date: 2017-08-29
CPC Classifications: C08F,C09K

Claim:
1. A drilling fluid additive composition comprising a viscosity reducer, an emulsifier, and a rheological modifier, wherein: a) the viscosity reducer is a double-block copolymer comprising a block A and a block B, wherein the block A is composed of structural units represented by formula (1), the block B is composed of structural units represented by formula (2), and the number-average molecular weight of the block A is 1,500-10,000; wherein R b) the emulsifier is one or more of compounds represented by formula (I); wherein each of the two R n is 1-8; wherein each X′ is independently selected from H or —C(O)—R2, and at least one X′ is —C(O)—R2, R2 is selected from carboxyl, C1-C6 alkyl, C3-C8 cycloalkyl, C1-C6 alkyl substituted by carboxyl, C3-C8 cycloalkyl substituted by carboxyl, C3-C8 cycloalkyl substituted by carboxyl and C1-C4 alkyl, C2-C6 unsaturated alkyl, C3-C8 unsaturated cycloalkyl, C2-C6 unsaturated alkyl substituted by carboxyl, or C3-C8 unsaturated cycloalkyl substituted by carboxyl and C1-C4 alkyl; c) the rheological modifier is a dimer acid-organic amine copolymer comprising structural units from dimer acid, structural units from an alkylamine and structural units from an arylamine, wherein the dimer acid is a dimer of oleic acid and linoleic acid, the alkylamine is one or more of C10-C20 alkyl primary amines, and the arylamine is one or more of aniline and aniline substituted by C1-C3 alkyl at one or more sites on benzene ring.