BACKFILLING MATERIAL Russian patent published in 2009 - IPC C09K8/467 

FIELD: oil and gas production.

SUBSTANCE: disclosed invention can be used at cementing of cased columns and at installation of cement bridges in oil, gas and gas-condensate wells with static temperature up to 40°C while opening sediments of mineral salts, including potassium-magnesium salts, and also complicated with presence of zones of abnormally low reservoir pressure in salt interlayers. The backfilling material contains, wt %: magnesite caustic powder 26.75-34.56; double superphosphate 0.92-1.23; magnesium chloride 13.75-16.01; Palygorskyt clay-powder 2.30-4.12; condensed micro-silica 9.22-10.29; sodium tripolyphosphate 0.92-1.23, water - the rest.

EFFECT: reduced density of magnesia backfilling material, reduced filter return, and increased adhesion of cement stone to salt rock and cased pipes.

1 ex, 1 tbl