METHOD OF ISOLATION OF BEDS WITH WATER FLOWS Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry; applicable in repair-isolation jobs for elimination of casing-borehole annulus overflows in cased oil and gas wells. SUBSTANCE: method includes lowering of perforator on tubing string into well, formation of cavern in well wall and forcing of cement slurry into bed. Said tubing string is provided with reference mark. Perforator is geophysically controlled with needed accuracy. Casing string is perforated to produce one or several through longitudinal slots over casing string to cover part of water-bearing bed facing the producing horizon, or to cover fully water-bearing bed, if it does not exceed 6-8 m. Formed in well wall, along said slots by washing with jet nozzle are through longitudinal caverns in bed rock. Then cement bridge is installed in interval of longitudinal slots with forcing of cement slurry into bed. Cement bridge is allowed to stand under pressure for setting. Then cement is drilled in interval of producing horizon. Producing horizon is perforated by hydromechanical slotting perforator to induce fluid inflow from producing horizon. Perforator is controlled with respect to roof of water-bearing bed, if it is located below producing horizon, and it is controlled relative to water-bearing bed foot, if it is located above producing horizon. EFFECT: increased reliability and service life of isolation of borehole zone in interval of beds with water flow. 3 cl