METHOD FOR SEALING PRODUCTION STRING OF PRODUCTION WELL Russian patent published in 2020 - IPC E21B33/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry, in particular, to production well repair method at loss of tightness of production string above payout bed. Method of sealing production string of producer includes detection of interval of failure of production string, mastering and cleaning of production string, sealing violation interval, lowering into production string of tubing string, equipped with bottom-up plug, perforated branch pipe, packer and pump, packer setting in the production string below its failure interval, starting the pump into operation. Determining the interval of disturbance of the production string is performed by means of the downhole pressure test of the production string from top to bottom, crimping of production string is additionally performed after detection of failure interval. If during pressuring of production string pressure does not decrease to zero within 15 minutes, after pressurizing at wellhead of production well, bottom-up layout is assembled: plug, perforated branch pipe, packer, flow column with pump, packer is set in production string below disturbance interval, but above productive formation, after which pump is started. If during pressuring of production string pressure is reduced to zero before 15 minutes expiration, productive formation is cut off from disturbance interval, specific intake of disturbance of production string is determined. If the specific pickup disorders g<0.5 m³/(chMPa), then produce a preliminary drainage disorders acid in volume of 1.5 m³ to achieve specific injectivity g>0.5 m³/(chMPa). If the specific pickup disorders g>0.5 m³/(chMPa), then the process pipe string is lowered and put drillable packer above violation interval, sealing of disturbance interval is performed by pumping into interval of disturbance of production string by alternating portions in equal volume of low-module liquid glass and cement solution, wherein the volume of each subsequent portion of the pumped low-modulus liquid glass and the cement slurry is 0.5 m³ less than the volume of the previous portion, and the volume of the first portion should not be less than 40 % of the total volume of pumping, low-modulus liquid glass and cement slurry are pumped in violation of the production string and the well is left waiting for hardening of the plugging components. A process pipe string and a packer are removed from the well; then, the packer is lowered on the pipe string and the packer is planted below the fault, and the production string is pressurized by the excessive pressure permitted on the production string via the annular space of the well. Sealing of the production string is determined, it is equipped with pumping equipment and the production well is put into operation.

EFFECT: improvement of quality of repair and reliability of sealing of production string disturbance above productive formation, as well as elimination of occurrence of emergency situation in well and simplification of technology of production string repair with application of packer.

1 cl, 4 dwg