Research On The Design Method Of PDC Bit Cutting Structure

PDC bit has the advantages of high rock breaking efficiency,long service life and other characteristics,and its performance has important influence on petroleum drilling process.The PDC bit cutting structure has a significant impact on rock breaking performance,therefore,research on the design method of PDC bit cutting structure is of great significance.The field application shows that the PDC bit is easy to discard as a result of the damage of cutter in the crown and the outer cone area.The analysis shows that among the bit cutting structure,the cutting angle of cutter and crown shape have great influence on the cutter's damage.This paper,by the way of numerical simulation study on the cutting process of single cutter,single blade and integrated blade bit,analysis the stress condition of cutter and the cutting structures' influence on it.The results show that the inner cone angle and the outer cone radius can influence the stress distribution of the bit.As the inner cone angle increases,the inner effective stress in the inner cone part increases.As the decrease of the outer cone radius,the extreme value of stress in the outer cone part increases,and the damage of the cutter in the corresponding position increases;larger outer cone radius helps to reduce the stress extreme value as well as the damage of the cutter.Reducing the inner cone angle of the drill bit and increasing the outer cone radius is beneficial to reduce the damage of the cutter,and realize the uniform wear of all cutters in the bit.The results can provide references for the design and optimization of bit cutting structure.