CLAY INHIBITOR COMPOSITION Russian patent published in 2023 - IPC C09K8/00 C09K8/04 C08F226/04 C08F226/10 

FIELD: clay inhibitors.

SUBSTANCE: group of inventions relates to a clay inhibitor composition comprising: a copolymer of diallyldimethylammonium chloride (DADMAC) and N-vinylpyrrolidone (VP), and water, the copolymer having a ratio of DADMAC:VP monomer units in the copolymer of 55:45 and a charge density of 6 to 9 mg-eq/g and molecular weight (Mw) from 50,000 to 150,000 Da, and also refers to a method for producing a copolymer of DADMAC and VP, including: radical copolymerization in an aqueous medium of DADMAC and VP monomers in the presence of a radical polymerization initiator and a chain growth control agent, where the initiator is µ-peroxo-bis(trioxosulfate) ammonium, the chain growth control agent is 2,2,6,6-tetramethylpiperidyl-4-hydroxy-1-oxyl, and the pH of the aqueous medium is from 6 to 7, and the resulting copolymer has the ratio of DADMAC:VP monomer units in the copolymer is 55:45 and the charge density is from 6 to 9 mg-eq/g and the molecular weight (Mw) is from 50,000 to 150,000 Da, and it also applies to drilling fluids.

EFFECT: group of inventions provides a shale inhibitor composition having and imparting to drilling fluids improved, in particular, low plastic viscosity and optimized rheological and structural-mechanical parameters, provides a shale inhibitor composition having effective and high shale inhibition, and demonstrating the required shale inhibition properties without adversely affecting the plastic viscosity, in particular the plastic viscosity of the drilling fluid; and also provides a clay inhibitor composition having high thermal stability, in particular in the range of 240-260°C and up to 260°C with the preservation of the necessary properties of the drilling fluid during and after exposure to high temperatures, and is able to control the rheological characteristics of the drilling fluid.

19 cl, 4 dwg, 4 tbl, 5 ex