CEMENTING COMPOSITION COMPRISING NONIONIC HYDROPHOBICALLY-MODIFIED CELLULOSE ETHERS AND USE THEREOF Russian patent published in 2018 - IPC C09K8/467 C04B24/38 C04B28/02 

FIELD: chemistry.

SUBSTANCE: invention relates to a composition and a method for cementing a casing in a borehole of a well using an aqueous cementing composition comprising: (a) water, (b) a cementing composition comprising (i) a hydraulic cement, (ii) a hydrophobically modified polymer, (iii) a dispersant and optionally (iv) one or more other additives conventionally added to aqueous cementing compositions useful in cementing casings in the borehole of wells. Hydrophobically modified hydroxyethyl cellulose preferably has an ethylene oxide molar substitution from 0.5 to 3.5, a hydrophobe degree of substitution from 0.001 to 0.025, and a weight- average molecular weight from 500,000 to 4,000,000 Da, and the dispersant is a sulfonated polymer, a condensation product of melamine and formaldehyde, a condensation product of sulfonated naphthalene and formaldehyde, a branched or unbranched polycarboxylate polymer. Aqueous cementing composition is preferably pumped downwards into said casing, pumped upwards into the annulus surrounding said casing until said aqueous composition fills that portion of the annular space desired to be sealed, and then maintaining said aqueous cementing composition in place until the cement sets. Invention is developed in subclaims.

EFFECT: technical result is an increase in the effectiveness of said composition and method.

16 cl, 1 tbl