MAGNESIA PLUGGING MATERIAL Russian patent published in 2009 - IPC C09K8/467 

FIELD: chemistry.

SUBSTANCE: invention relates to oil-and-gas industry, and specifically to magnesia plugging material and can be used in casing cementing and installing sealing and strong bridges in oil, gas and gas-condensate wells with maximum static temperature of up to 55°C, drilling in deposits of mineral salts, including potassium-magnesium, which are prone to plastic flow, and complicated by presence of zones with abonormally low formation pressure in the inter-salt layers. The magnesia plugging material contains, wt %: caustic magnesite powder 19.98 to 26.29; magnesium chloride - 17.63 to 19.29; double superphosphate - 1.11 to 1.18; sodium tripolyphosphate - 0.61 to 0.91; boric acid - 0.40 to 0.73; palygorskite mud powder - 3.03 to 4.54; condensed microsilica - 11.12 to 11.81; water - the rest.

EFFECT: obtaining magnesia plugging material, solution of which is chacterised by low density, acceptable setting times and temperature in the well of 55°C, and forming a sufficiently strong cement stone - high corrosion resistance in fresh and hard stratal water.

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