HYDROMECHANICAL SLOT-TYPE PUNCHER (VERSIONS) Russian patent published in 2013 - IPC E21B43/112 

FIELD: oil and gas industry.

SUBSTANCE: hydromechanical slot-type puncher consists of a body, an ejector-piston inside the body and a cutting unit underneath the ejector-piston; the latter includes retractable cutting tools with retraction mechanism in the form of a double-arm lever (balancing lever), cutting tools are installed in its arms and a correcting wedge installed under the balancing lever; at that balancing lever is mounted at a movable axis and it can rotate when its lower arm comes in a contact with correcting wedge in case of downwards movement of the ejector-piston. According to the invention the ejector-piston is made as a wedged piston; it can act on the upper arm of the double-arm lever that retracts the upper cutting tool thus creating opposite forces formed by the wedged piston and correcting wedge, which act on the upper and lower arms of the lever simultaneously. A version with enlarged cutting unit with more than two cutting tools is suggested.

EFFECT: uniform opening of the production string in at least two projections with guaranteed formation of equal high-quality slots.

6 cl, 2 dwg