Study On PDC Single-tooth Rock Breaking Mechanism In Ultra-deep Bottom Hole Stress Environment

PDC drill bit is one of the most commonly used drill bit types in drilling operations.PDC teeth have high hardness and good wear resistance.They have the characteristics of fast ROP and stable performance in shallow formations,and high comprehensive economic benefits.At the time of drilling operations,as the depth of the well increases,the bottom hole environment becomes more complicated.Increasing the drilling speed of deep formation drilling is of great significance for reducing drilling time and cost.Therefore,it is of great significance to study the single-tooth rock breaking mechanism of PDC bit suitable for ultra-deep environment.In this paper,the law of PDC single-tooth broken rock under ultra-deep conditions is studied.At the same time,the geometric parameters of PDC cutting teeth(Back rake angle,Side rake angle),environmental parameters(temperature,pressure),drilling operation parameters(drilling weight,rotate speed)are broken.The numerical simulation of the influence of the rock was carried out,and the indoor experiment was carried out to verify the simulation results.The results show that the PDC cutting tooth back rake angle is better in the range of 15° to 20°.The rock breaking law is basically the same as the normal temperature and normal pressure under high temperature and high pressure conditions;the ROP increases with the increase of temperature and decrease with the increase of the confining pressure.This study provides a reference for the optimization of bit structure and the optimization of drilling parameters in the future.