Amphiphilic reservoir protecting agent and preparation method thereof and drilling fluid

摘要

The present subject matter relates to an amphiphilic reservoir protecting agent, including structural units denoted by the following formula (1), (2), (3) and (4). The present subject matter further provides a method for preparation of an amphiphilic reservoir protecting agent. The present subject matter further provides a drilling fluid that contains the amphiphilic reservoir protecting agent. The amphiphilic reservoir protecting agent and drilling fluid obtained in the present subject matter have high reservoir protection property and high shale inhibition property.;

主权项

1. An amphiphilic reservoir protecting agent, consisting of structural units denoted by following formula (1), (2), (3) and (4): wherein R1, R2, R3, R4, and R5 independently are H, C1-C4 alkyl or C1-C4 alkoxyl; R6 and R6′ independently are C1-C3 alkyl; R7 is C1-C6 alkyl; M is H or an alkali metal; R8 and R8′ independently are C1-C6 alkyl, phenyl or C1-C6 alkyl substituted phenyl; wherein a molar ratio of the structural units denoted by formula (1):the structural units denoted by formula (2):the structural units denoted by formula (3):the structural units denoted by formula (4) is 1:0.4-2:0.5-1:0.1-0.5; wherein a weight-average molecular weight of the amphiphilic reservoir protecting agent is 150,000-350,000 g/mol, wherein the amphiphilic reservoir protecting agent is a copolymer formed by initiating a polymerization reaction of a mixture of monomers of the structural units.