DRILL BIT, SYSTEM AND METHOD OF WELL-BORING IN SUBSURFACE BED Russian patent published in 2008 - IPC E21B10/36 

FIELD: machine building.

SUBSTANCE: set of inventions relates to drill bit, borehole and method of well-boring in subsurface bed. The drill bit with a central lengthwise axis can rotate around the said axis and reciprocate to bring about impact effects on the well bottom. The drill bit features a surface furnished with a set of chipping and cutting elements with a scraper surface facilitating a rotary scraping travel along the well bottom. The scraper surface in operation gets arranged at a front angle in the rear plane not exceeding 90° and defined as an angle included between the projection of a line perpendicular to the said scraper surface on the plane defined by the central lengthwise axis and the direction of the tangent line of chipping cutting element velocity component and the plane perpendicular to the lengthwise axis. Here note that one or several chipping cutting elements are furnished with a cutting flat impact surface, in fact, parallel to the plane perpendicular to the lengthwise axis. The drilling system incorporates a string containing the said drill bit. The drilling method consists in using the aforesaid system.

EFFECT: longer life and higher efficiency of the chipping cutting elements.

12 cl, 7 dwg