Study of a New Type of Compound Percussion Drilling Tool

Abstract

The stick-slip vibration is a kind of serious vibration which could cause serious damage to downhole tools and decrease the rate of penetration. The root cause of the stick-slip vibration has been analyzed, which indicate that the high reactive torque is the main cause of the bit-related stick-slip vibration, while the nonlinear friction force between the drill string and the borehole is the main cause of the string-related stick-slip. In order to mitigate the stick-slip and improve the ROP, a new type of composite impact drilling tool has been designed, this tool can transfer part of the hydraulic energy to the high frequency axial impact energy and the torsional impact energy to auxiliary to fail the formation. The composite impact could break the stick phase of the bit and decrease the friction force between the drill string and the borehole, which could effectively improve the drilling efficiency and ROP.