METHOD OF SALT WATER FILLED SUBSURFACE TANK WELL SEALING Russian patent published in 2009 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to operation of subsurface tanks in rock salt and can be used in gas, oil and other industries. According to method of salt water filled subsurface tank well sealing, clear opening is provided in tank filler neck under casing shoe through extracting portion of salt water and introducing mixed diesel fuel, clay and carboxymethyl cellulose into the well in ratio, wt %: 58:38:4, thus forming floating insulating layer on salt water surface. Then suspended pipe string is closed at the shoe with its walls perforated. Portland cement grout is supplied on the specified layer after plastic clay plug is formed. Suspended pipe string is removed on the surface, and sealing compound is supplied that is magnesium slime or nepheline concentrate processed with sulphuric acid with using squeesing liquid (extracted salt water) and kept under pressure till hardening. When annular space is sealed, hardened materials are drilled out along the vertical well axis, and suspended pipe string is lowered into the tank. Invention is developed in subclaims.

EFFECT: higher efficiency of well sealing, lower work content and costs for recovery work.

3 cl, 2 dwg, 2 ex