METHOD OF PRODUCTION STRING SEALING Russian patent published in 2014 - IPC E21B33/122 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, in particular, to methods of production string sealing. Method of production string sealing includes running-in of two packers interconnected by a tube at a setting tool made as a flow column, setting of these packers in production string above and below the failure and further removal of the setting tool. Before seal failure appears in the production string radial openings are made at the lower end of the setting tool and a limiter is installed below the radial openings; in initial position the radial openings are covered by a hollow sleeve capable of limited axial movement till it rests upon the setting tool limiter and fixes in the setting tool; when seal failure occurs at the well head the following assembly is arranged bottom-up: the lower packer, a tube, the upper packer, the left crossover shoe; then the assembly is set at the setting tool to the place of leak failure in the production string; thereafter the packers are seated and sealing of the lower packer seating is checked; for this purpose a geophysical tool is run in at the setting tool to the point of the lower packer location and geophysical study is made; then the geophysical tool at the cable is removed from the well and at the well head a rubber plug with metal tip from the bottom is inserted into the setting tool, the plug is pressed into the setting tool until the metal tip fixes in the hollow sleeve; herewith the plug shuts off two-packer setting tightly from the setting tool and radial openings in the setting tool are open and communicate the inner space of the setting tool and tubing-casing annulus above the upper packer; thereafter level of fluid is decreased in tubing-casing annulus above the upper packer by swabbing against the setting tool and sealing degree of the upper packer seating is determined; in case of sealed seating of both packers the setting tool is rotated clockwise starting from the well head thus unscrewing it from the left crossover shoe and the setting tool is removed from the flow string to the surface; in case of untight seating of at least one packer both packers are unset and the whole assembly is removed for inspection, thereafter all the above operations are repeated. There's a possibility to check tightness of both the upper and the lower packer and removal of two-packer unit to the well-head in case of untight seating of at least one packer thus providing high effectiveness of production string sealing by two-packer units.

EFFECT: suggested method of production string sealing is simple as far as the whole sealing process is carried out during one tool running.

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