WELL OPENER Russian patent published in 2010 - IPC E21B7/28 

FIELD: oil-and gas industry.

SUBSTANCE: well opener contains a case with a central channel, an expanding legs with tooth, evenly installed along the case external perimetre on a guide, located in the case central channel spring loaded in a direction opposite to movement rod with a ring piston and elements for the rods load transferring to the legs at their movement into operation position, made as a bar and executing back-and-forth displacement. The case equipped with radial holes and channels, also - external stop blocks, between each a installed a guide, executed as a void cylinder with longitudinal cuttings between legs, stiffly fixed on its surface, and internal cylindrical ending thickenings, hermetically interaction with the case, at that one of the ending thickenings executed with ability of longitudinal movement towards to the other one, also the rod executed with ability to limited downwards movement, at its external surface there is a conical surface, widening form the top to the bottom, at that rods installed in to the radial channels, created evenly along the case perimetre, with ability of radial movement and interaction with the rod conical surface from inside, but form outside - with the guide under legs and tooth, at that inside the void cylinder of the guide, in a cavity created between the case and the guide's cylinder and connected via radial holes to the central channel, installed an elastic sleeve with antiflow opposite to the cuttings, hermetically fixed on the ending thickenings and equipped with a technological holes for rods.

EFFECT: well opener operation efficiency increase.

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