METHOD TO PREVENT COLLAPSING OF CASING STRINGS WHEN BUILDING UNDERGROUND RESERVOIRS IN CHEMICAL DEPOSITS Russian patent published in 1999 - IPC

FIELD: mining industry; operation and construction of underground reservoir storage. SUBSTANCE: proposed method provides for sealing of reservoir in top and sole, drop of excess pressure from outer surface of pipe casings by forming hydrodynamic coupling of casing string annulus and inner surface of casings through passages in form of holes. Passages are made before mounting and lowering of casing strings into well and are overlapped by system of relied valves by means of which pressure is reduced in annuals automatically when it rises near outer surface of casing strips to value close to or equal to 2/3 rds of tolerable collapsing pressure. Passages can be made in connecting members of casing strips. EFFECT: provision of conditions preventing collapsing of casing string sealed in underground reservoir. 2 cl, 4 dwg