WELL CONVERSION METHOD, INCLUDING FLOODED WELLS, FOR OPERATION WITH TWO PRODUCTION STRINGS AND DEVICE FOR ITS IMPLEMENTATION

FIELD: oil and gas industry.SUBSTANCE: method running-in and suspension of the central production string, installation of the upper part of X-mas tree, refitting of the wellhead by installation of system for monitoring and control of the well operation, performance of gas-dynamics research, flow start-up of the well through two production ring and system for monitoring and control of the well operation. At the beginning and ending of the main production string the upper and lower bits are installed respectively and a plug and a pilot-operated valve in closed position is joined to the upper and lower bits. Then the central production string is mounted to the launching and lifting gear, the master valve is closed, a radial pipe holder is installed at the master valve, an a stop valve is installed over the master valve at the pipe holder, a preventer is joined to it and a double-chamber pressuriser is installed at the preventer, an injector is connected to the upper butt end of the pressuriser and a launching and lifting mechanism is installed in direct vicinity from the well. Thereafter the central production string is passed by its end through the injector, which is used to move the central production string, the central production string is passed through the double-chamber pressuriser, pressure is supplied to its closing hydraulic cavities thus compressing packing seals of the upper and lower chamber of the double-chamber pressuriser and the central production string is sealed. Then it is run down up to the master valve level, the central production string is run down to the position when the upper bit with plug is at the level of the injector upper butt end, the rod is connected to the plug, pressure is delivered to the opening hydraulic cavity in the upper chamber of the pressuriser, in result the packing seal of the upper chamber of the double-chamber pressuriser is released, the central production string is run down to the position when the plug is below the packing seal of the upper chamber in the double-chamber pressuriser. Pressure is supplied to the closing hydraulic cavity of the upper chamber in the double-chamber pressuriser thus sealing the rod. Pressure is supplied to the opening hydraulic cavity of the lower chamber in the pressuriser, in result the packing seal of the lower chamber in the double-chamber pressuriser is released, the central production string is run down to the position when the plug is below the packing seal of the lower cha