METHOD OF WELL-DRILLING WITH SIMULTANEOUS CASE AND FACILITY FOR ITS IMPLEMENTATION Russian patent published in 2008 - IPC E21B7/20 

FIELD: mining.

SUBSTANCE: method includes destruction of circumferential and central parts of well bottom by means of percussive-rotary effect on it by case- drilling tool, containing percussive coring bit and central bit, at simultaneous forwarding of casing to the side of bottomhole under shock pulses. Initially it is destroyed circumferential part of bottomhole by percussive coring bit with forming in bottomhole central part core till its contact with central bit butt, after what - core, proceeding destroy of circumferential part of bottomhole by percussive coring bit. Device includes casing with internal lug in front part, submersible shock machine with case- drilling tool, containing local energy carrier circulating system, percussive coring bit with fore and caudal step, the last of which is located freely inside of casing, and central bit, installed in submersible shock machine with ability of interaction with percussive coring bit at passing to it shock pulses and rotational moment. Central bit is installed on butt of caudal step of percussive coring bit, which is outfitted by sleeve, interacting to internal lug of casing and connected to central bit by means of movable spline connection. Efficiency increase of method at the expense of energy intensity of destroying process decreasing for well bottom, improving of passing conditions of rotational moment and reliability growth at the expense of device design simplification.

EFFECT: effectiveness increase and reliability growth of drilling.

3 cl, 3 dwg