Working Load Characteristics of the PDC-Cone Composite Bit under Impact and Scraping

Table 1

Working load calculation conditions of 8-1/2 inch, 2 + 4 hybrid drill bit.

Rock condition parameter		Drilling condition parameter
Rock type	Compressive strength	Internal frictional angle	Drill ability	Rate of penetration	Well depth	Rotation speed	Ratio of velocity between cone and bit
Nanchong sandstone	67.55 MPa	38.03°	5.48 (PDC)	6.5 m/h	3500 m	80 r/min	1.3