Drill bit 1

the tool used to crush/scrape rock. bit selection has a big impact on well cost.

occurs by exceeding the shear strength, involves the use of a bit tooth to shear, or cut, the rock into small pieces

occurs by exceeding the compressive strength, requires that the load placed on the rock exceeds its compressive strength.

• 1. The compressive strength of the rock exceeds the load (WOB)
• 2. The load is removed before it is transmitted from the bit tooth to the formation (RPM)

Failure occurs when shear stress. ζ