METHOD TO RESTORE TIGHTNESS OF BOREHOLE ANNULUS IN WELL OF GAS FIELD OR FIELD THAT CONTAINS NATURAL GAS IN ITS PRODUCE Russian patent published in 2011 - IPC E21B33/10 

FIELD: construction.

SUBSTANCE: method to restore tightness of borehole annulus in a well of a gas field or a field that contains natural gas in its produce, relates to oil and gas producing industry and may be used in reconstruction, repair, preservation and liquidation of wells with gas-untight borehole annulus at fields and underground gas depots (UGD). The method includes formation of a ring channel in a well to connect borehole annulus and tubing of the well. On completion of the ring channel formation, production tubing is lowered into the well, equipped with a packer and a circulation valve. The ring channel and the joined borehole annulus are filled with liquid via the circulation valve of the production tubing. Variation or maintenance of density and/or height of the pumped liquid column above the formed ring channel are used to provide for permanent exceeding of hydrostatic pressure of the liquid column over the layer pressure of gas.

EFFECT: simplified and more efficient method to restore tightness of borehole annulus.

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