Volume 52

Characteristics of Axial Percussive Force of Two-cutter PDC Bit on Carbonate Rock Xinkang Fu, Zhongwei Huang, Luhai Wang, Huaizhong Shi, Guodong Ji

Abstract

The carbonate reservoir is rich in oil and gas resources and has great exploration potential. The deep carbonate rock has poor drill-ability. Percussive drilling technology has been verified to notably enhance the rock-breaking efficiency in deep and ultra-deep formations. However, the law of rock breaking under different parameters of axial percussion is not clear. A set of experimental equipment for percussive drilling was established. A series of axial percussive drilling tests under different percussive parameters with a double-cutter PDC bit were carried out on carbonate rock. The study analyzed the relationship between axial force and percussive frequency, as well as the relationship between axial force and percussive amplitude. The results indicate that the average value and fluctuation amplitude of the axial force are minimized at the frequency of 16 Hz. When the amplitude of axial percussion reaches 0.8 mm, the average axial force is at its lowest point. The optimum axial percussive amplitude is 0.8 mm. Excessive percussive amplitude is detrimental to rock breaking. The findings will be helpful in determining the optimal parameters for axial percussive drilling.

Keywords percussive drilling, PDC cutter, percussive frequency, carbonate rock, percussive amplitude