DRILL BIT FOR WELL DRILLING ON OUTBURST-PRONE SEAMS Russian patent published in 2009 - IPC E21B10/38 

FIELD: oil-and-gas production.

SUBSTANCE: invention relates to a rock-breaking tool, used when drilling wells in seams with high content of gas, where the drilling process is frequently accompanied by micro-outbursts. The drill bit has a composite body with flushing ports and a conical saddle, and a conical shutting-off device with a spring, fitted inside the body with possibility of axial movement. The distinctive feature of the drill bit is that, the shutting-off device is joined to the body by a cross bar with a suspender, rigidly attached to the shutting-off device and the cross bar. The suspender used is a tension spring. The tension spring has a protective cover in form of a cylinder, and the shutting-off device has on its top end an annular channel under the protective cover of the spring.

EFFECT: increased safety and efficiency of the drill bit due to cutting on downtime for cleaning off mud and significantly lower probability of occurrence of accidents.

2 cl, 2 dwg