BLADE DRILLING BIT (VERSIONS) Russian patent published in 2015 - IPC E21B10/55 

FIELD: machine building.

SUBSTANCE: according to the first version a blade drilling bit comprises a casing with connection thread, central channel and outlet holes for drilling fluid, blades with a passive calibrating part with its surface being protected by hard-alloy layer and reinforced by diamond cutters PDC, the diamond cutters PDC are made with bevelled rear edge, the value of the back bevel amounts to 20% of the diameter of the diamond cutter itself at the angle of 25-60°. According to the second version a blade drilling bit comprises a casing with connection thread, central channel and outlet holes for drilling fluid, blades with a passive calibrating part with its surface being protected by hard-alloy layer and reinforced by diamond cutters PDC, the diamond cutters PDC are of spherical shape.

EFFECT: use of the proposed group of inventions will allow for better impact resistance of the passive calibrating part structure and thus for longer preservation of the rig diameter preventing deviations from the specified diameter of the well being drilled.

6 cl, 7 dwg