Research On Rock Breaking Mechanism And Design Of Roof-tooth PDC Bit

The ridge cutter is a new PDC cutting cutter which has been developed in recent years.It has unique cutter surface structure,which is helpful to change the interaction mode between conventional PDC cutter and rock.Compared with the ordinary PDC bit,the ridge PDC bit is stabler.It can reduce the torque greatly and improve the drilling speed.But there is still a lack of research on the rock-breaking mechanism and designed theory of the ridge PDC bit.Based on the theoretical research of the conventional PDC bit theory,the author establishes the basic geometry theory of the ridge PDC bit.The author analyzes the interaction relationship between the ridge cutter and the rock through theoretical calculation and ABAQUS finite element simulation tests and further clarify the mechanism of rock breaking,which provides theoretical support for the design of the PDC bit of the ridge cutter.This author mainly completes the following tasks:(1)Analyze the structure and working principle of the ridge PDC bit;establish the basic theory of PDC geometry and cutting geometry of the ridge PDC bit according to the theory of conventional PDC bit.(2)Define the actual front rake and the actual side rake of the ridge cutter face;analyze the influence of the different working angles of the ridge cutter on them on the basis of the PDC bit geometry.(3)Make force analysis of interaction between ridge cutter and the rock.Establish balance equation of the cutting load.(4)Analyze the influence of different working angles of ridge cutter on relative invasive ability,cutting load and cutting efficiency of relative cutters through theoretical calculation and ABAQUS finite element simulation tests,and make the further analysis of the mechanism of rock breaking.(5)Puts forward the individualized design theory of the ridge-cutter PDC bit in this stratum aiming at the failure analysis of PDC bit in complex formation.The research provides theoretical support for the next numerical simulation of the PDC bit of the ridge and enhance the understanding of the interaction between the ridge cutter and rock and the rock breaking mechanism,which provides references for the personalized design of the ridge-cutter PDC bit.