Experimental Study on Rock Fragmentation Efficiency of Two Stage PDC Bit

Abstract

This paper proposes a two-stage PDC bit that can actively release the formation pressure in advance to improve the rock breaking efficiency, and provides a new solution for effectively improving the rock breaking efficiency of the deep hard formation. The red sandstone drilling comparison experiment under the same drilling parameters of the two-stage PDC bit and the conventional PDC bit is carried out. The experimental results show that the two-stage PDC bit can effectively improve the rock breaking efficiency under the same conditions and compare with the conventional PDC bit. The speed increase efficiency can be up to 90%; the use of two-stage drill can greatly reduce the rock breaking torque during the drilling process. Under the same working conditions, the double-stage PDC bit can reduce the rock breaking torque by up to 30%, and the two-stage The mechanical specific energy of the drill bit is generally lower than the mechanical specific energy of the conventional drill bit, and the relative reduction of the mechanical specific energy under the same conditions is between 5% and 25%. And effectively reduce the ineffective vibration of the drill bit, thereby achieving the purpose of protecting the drill bit and increasing the life of the combination of the drill bit and the bottom drill.