METHOD OF PREPARATION OF GROUTING COMPOSITION Russian patent published in 2002 - IPC

FIELD: construction of oil and gas wells, particularly, methods of preparation of grouting compositions designed for fastening of casing strings of low- and high-output formations. SUBSTANCE: method includes mixing of oil-well portland cement, polymer based on cellulose ether and water in which setting accelerator is preliminarily dissolved. Simultaneously in mixing with water, portland cement and said polymer in dry or swollen state are introduced. Mixing of components is continued for 1-1.5 h. Setting accelerator is used in form of calcium chloride or ethyl silicate, or reagent based on aluminum. Polymer based on cellulose ether is used in form of oxyethyl cellulose or hydroxyethylcellulose. Grouting composition contains the following amounts of components, wt.p.p.: oil-well portland cement, 100; oxyethylcellulose or hydroxyethylcellulose, 0.2-0.6; calcium chloride, or ethyl silicate, or aluminum-base reagent, 1-3; water, 45-50. Additionally introduced into grouting composition may be plasticizer in form of reagent based on melamine, and lignosulfonate. EFFECT: excluded crossflows between formations, higher quality of well cementing due to reduced shrinkage deformation, increased strength and reduced permeability of cement stone, optimal parameters of obtained composition. 2 cl, 2 tbl, 1 ex