METHOD FOR ENLARGEMENT AND REAMING OF WELL SHAFT Russian patent published in 2015 - IPC E21B10/26 

FIELD: oil and gas industry.

SUBSTANCE: method for enlargement and reaming of a well shaft is implemented by means of a tool including a hollow housing with a flushing hole on an end face; the lower part of the housing has end and side surfaces, and the upper shank part of the device has the shape of a cylinder ended with a thread; the lower part of the housing consists of a pilot centring part having a cylindrical shape, on the side surface of which there are flushing ports, and a diverging part. As a tool, a bit is used, the lower part of the housing of which has end and side working surfaces reinforced with armour, and the diverging part of the lower part of the housing is provided with blades and has the shape of cylinder of larger diameter, in the inter-blade space of which flushing ports are arranged.

EFFECT: excluding deviation from direction of the pre-drilled shaft and improving operating properties.

7 cl, 6 dwg