Tri-cone Bit

Classification of tri-cone bits

1. Bearing type: rolling bearing and sliding bearing
2. Seal type: rubber seal and metal seal
3. According to the fixing method of the teeth, it can be divided into: inlaid teeth (tungsten carbide teeth) tri-cone bits and milling teeth (steel teeth) tri-cone bits

Working principle of tri-cone bit

Under the action of drilling pressure and drill string rotation, the teeth of the roller cone bit are crushed and eaten into the rock, and at the same time, a certain amount of sliding is generated to shear the rock. When the cone rolls at the bottom of the well, the teeth on the cone impact and press into the formation in turn. This action can crush a part of the rock at the bottom of the well, and at the same time, the shearing action caused by the sliding of the cone cuts off the remaining remaining between the teeth. A part of the well breaks the rock at the bottom of the well, and the wellbore can be extended.

Commonly used tri-cone bit specifications:

6 inch, 6-1/2 inch, 8-1/2 inch, 9-1/2 inch, 10-5/8 inch, 12-1/4 inch

	Tooth shape	WOB	Rotating speed	Applicable situation
	517 wedge teeth	0.35-0.9	80-60	Soft to medium formations with compressive strength, such as mudstone, gypsum, salt rock, soft shale, soft limestone.
	537 punching teeth	0.35-1.0	80-60	Soft to medium formations with compressive strength, such as medium soft shale, medium soft limestone, medium soft sandstone and medium ground with soft and hard abrasive interlayers.
	617 bevel teeth	0.45-1.1	60-40	Medium-hard formations with high compressive strength, such as shale, limestone, sandstone and dolomite.
	637 bevel teeth	0.45-1.1	60-40	Hard formations with high compressive strength, such as sandstone, limestone, dolomite and anhydrite, marble.
	637 ball teeth	0.52-1.2	60-40	Hard formations with high compressive strength, such as sandstone, limestone, dolomite and anhydrite, marble.