BICENTRAL BORE BIT Russian patent published in 2009 - IPC E21B10/26 

FIELD: oil and gas production.

SUBSTANCE: invention refers to rock destroying tool used for boring oil and gas boreholes with simultaneous wall cavitation of borehole. The bicentral bore bit with lengthwise axis of rotation consists of a tail piece with a connecting thread, of a pilot, of an eccentric boring head and sub-boring head assembled between the pilot and the boring head; the bore bit is equipped with blades, on surfaces of which there are arranged cutting elements. The blades of the pilot are set off relative to plane passing through the axis of rotation of the tool and axis of boom drift diametre at 20-80°, the blades of the sub-boring head are set off relative to the blades of the boring head at 20-80°. Teeth on the first blade of the sub-boring head and the second blade of the pilot are assembled on the whole blade right up to a bit gage surface. The teeth on the first blade of the pilot and the second blade of the sub-boring head are set off from the end of the gage surface of the blade to axis of the bore bit at distance of from 0.5 to 5 mm.

EFFECT: implementation of invention facilitates increasing service life of bore bit and decreasing duration of well construction.

17 dwg