METHOD OF RECOVERY OF BOTTOM-HOLE FORMATION ZONE OF GAS WELL Russian patent published in 2002 - IPC

FIELD: gas producing industry; applicable in recovery of bottom-hole formation zone and isolation of water inflow in casing string - borehole annulus in major repair of gas wells. SUBSTANCE: method includes preparation of oil-emulsion grouting slurry. Volumes of portions of oil-emulsion grouting slurry and displacing fluid are calculated by empirical formulas. Oil-emulsion grouting slurry is injected and forced through tubing string with simultaneous withdrawal of gas through tubing string. Depression on formation is gradually increased up to beginning of formation water carrying out. In the course of injection and forcing of oil-emulsion grouting slurry, value of actual wellhead gas pressure is compared with its maximum permissible value which is determined by empirical formula. Upon attainment of maximum value of wellhead gas pressure, gas bleeding off is started. Bleeding off rate is calculated by empirical formula. Gas is bled off until moment of ending of injection and forcing of oil-emulsion slurry. Well is killed. Excessive grouting slurry is washed out. Cement sleeve is removed from flow string. Sump is cleaned. Setting of grouting slurry is waited for. Well is completed. EFFECT: higher efficiency and reliability of recovery of bottom-hole formation zone with simultaneous shutoff of water inflow to casing-string - borehole annulus with preserved reservoir properties of formation. 2 cl, 4 dwg