DRILLING FLUID CONTAINING POLYMER AND USE OF POLYMER IN DRILLING FLUID Russian patent published in 2010 - IPC C09K8/35 

FIELD: chemistry.

SUBSTANCE: invention relates to drilling fluids. The drilling fluid contains a polymer which contains at least 65 wt % hydroxylated links of the following formula: -CH₂-CR⁶[-X²-R⁸]-, where R⁶ is a hydrogen atom or methyl group, X² is a group of formula -CO-O-, -CO-NH- or -C₆H₄-CH₂-, R⁸ is a hydrocarbon group with at least two carbon atoms, which contains at least two -OH- groups, preferably on two neighbouring carbon atoms. The said polymer is used in drilling fluid as a clay swelling inhibitor and/or as a concretion inhibitor, and/or as a regulator of rheological properties of the fluid, and/or as a fluid-loss reducer, and/or as a lubricant. The invention is developed in subclaims.

EFFECT: prevention of clay swelling and destruction of walls of the well with simultaneous inhibition of concretion without increasing viscosity of the drilling fluid and without restricted use of the drilling fluid in high temperature and pressure conditions.

14 cl, 1 ex