FIELD: chemistry.
SUBSTANCE: method of sealing an underground formation includes preparing a sealing composition containing an aqueous fluid medium, a diutan compound and at least one gel system. The gel composition includes a polyethyleneimine crosslinking agent and anti-leak material. The diutan compound contains unclarified diutan, clarified diutan and any combination or derivative thereof. The anti-leak material contains at least one micronised material, at least one water-soluble hydrophobically modified polymer and combinations thereof. The sealing composition is fed into a drilled well passing through an underground formation. A plug is formed from the sealing composition.
EFFECT: improved sealing composition.
12 cl, 3 ex, 3 tbl, 3 dwg
