METHOD FOR INCREASING TIGHTNESS OF ANNULAR SPACE OF OIL AND GAS WELLS (OPTIONS) Russian patent published in 2022 - IPC E21B33/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry; it can be used for the prevention of tightness loss of an annular space of wells under breaking loads developed during the operation of wells on oil and gas fields, in the operation of wells on underground gas storages (UGS), as well as after the liquidation of spent wells. The invention can also be used for increasing the resistance of bottom-hole zones of producing wells, and reduction in rock microparticle volumes carried out to these wells with a flow of produced reservoir fluid. A method for increasing a level of tightness of an annular space of oil and gas wells includes drilling of a well, casing string descent, plugging of the annular space of the well. Before the casing string descent, a wellbore is expanded on at least one section at an interval of impermeable rocks. The method for increasing the tightness of the annular space of liquidated spent wells includes cutting out sections of the casing string. Centering devices with a nominal diameter exceeding an initial diameter of the wellbore are rigidly installed in the casing string at the level of this section/sections. At the same time, the annular space of the well is plugged with material expanding when solidified, at least to a level exceeding the location of an upper expanded section of the wellbore.

EFFECT: reduction in negative consequences caused by the reduction in a level of tightness of an annular space, as well as increase in the resistance of bottom-hole zones of wells to breaking loads.

3 cl, 3 dwg