INSULATION METHOD FOR BEHIND-THE-CASING FLOWS IN PRODUCTION WELL Russian patent published in 2020 - IPC E21B33/138 E21B43/32 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil industry and can be used for repair of annulus of production well at occurrence of behind-the-casing flows of fluid between beds. Substance of the method consists in that horizontal channels are made in the water-flooded formation roof and a blocking composition is pumped. Then, horizontal channels are made in the bottom of the crosspiece and specific intake capacity of horizontal channels in the bottom of the crosspiece is determined. Thus if the specific pickup horizontal channels less than 0.6 m³/(hMPa) before isolation annulus produce horizontal drainage channels acid injection in volume of 0.75 m³ per 1 m of height of the horizontal channels, followed by swabbing. Further, on the process string, a setting tool is lowered into the well with a drilled packer equipped from below with a nipple with side holes inserted into the packer pass channel with possibility of tight longitudinal movement and equipped from below with plug for isolation of packer pass channel. Drilled packer is placed above horizontal channels in interval of web below payout bed. When annular valve is open, liquid is caused to circulate along process pipe string, through horizontal channels of setting tool and drilled packer and behind-the-casing space before fluid outlet at production well mouth through open valve. Then grouting mortar is pumped and poured in volume of 50 % of total volume of grouting mortar till grout mortar is released through intervals of productive formation perforation. Annular gate valve is closed and the columned space is backfilled by cyclic injection of the grouting mortar to permissible pressure on the productive formation with holding to pressure drop in 2 times from the permissible value in the first cycle with subsequent increase of the bottom pressure by 1.0–1.5 MPa with each subsequent cycle to stabilize the squeezing pressure of the grouting solution equal to the allowable pressure on the productive formation to form a cement plug above the drilled packer. After that, the annular gate valve is opened and the process pipe string is removed from the well with the setting tool, the well is left for process holding of solidification of the grouting mortar, after that, grooving bridge and drillable packer are drilled, productive formation is perforated.

EFFECT: higher reliability of implementing technology, high efficiency of sealing a flooded formation, lower pressure of squeezing grouting in the borehole annulus, higher quality of sealing borehole annulus.

1 cl, 6 dwg