| 摘要 |
Disclosed is 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) an anionically- and 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. Preferably the anionically- and hydrophobically-modified hydroxyethyl cellulose has an ethylene oxide molar substitution of from 0.5 to 3.5, a hydrophobe degree of substitution of from 0.001 to 0.025, an anionic degree of substitution of from 0.001 to 1, and a weight-average molecular weight of from 100,000 to 4,000,000 Daltons and the dispersant is sulfonated polymer, melamine formaldehyde condensate, a naphthalene formaldehyde condensate, a branched or non-branched polycarboxylate polymer. Preferably, the aqueous cementing composition is pumped downwardly into said casing, pumping upwardly 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. |
