Rock Breaking Mechanism And Computer Simulation Of Hybrid Drill Bits

In recent years,the consumption of shallow oil and gas resources has been huge,Difficult drilling operations are increasing and shale gas development has become a hot spot.As a result,problems such as excessive tooth wear and a significant drop in mechanical drilling speed during drilling with conventional bits are difficult to obtain the ideal drilling effect.The successful design and application of hybrid drill bits abroad in recent years have shown that it has a rock-breaking advantage over conventional drill bits,but at present there is very little research on the rock-breaking mechanism,resulting in limited promotion of hybrid drill bits.Therefore,this paper uses a combination of theory and simulation to carry out research on the rock breaking mechanism of hybrid bits.The specific research contents are as follows:(1)Understand the rock breaking process of PDC bit and roller cone bit,and then study the rock breaking mechanism of mixed bit.The results show that the rock breaking of the mixed bit is the result of the combined action of the cone teeth and PDC teeth on the rock,thereby increasing the rock breaking speed.(2)By analyzing the rock breaking force of PDC structure and cone structure,the rock breaking mechanics formula of hybrid bit is derived.(3)The rock breaking simulation of the hybrid drill bit,roller cone bit and PDC bit is conducted to verify that the hybrid drill bit has better rock breaking efficiency than the roller cone bit and PDC bit.(4)The influence of the hybrid drill bit structure on the rock breaking mechanism was studied,and it was found that the cone-dominated hybrid bit is suitable for relatively hard formations;the PDC-dominated hybrid bit is suitable for relatively soft formations.(5)Study the shale breaking mechanism.The interaction mechanism between the hybrid bit and the layered rational shale is studied.The results show that: the smaller the angle formed by the hybrid bit and the rock bedding,the faster the drilling speed;the smaller the bedding thickness,the faster the rock drilling speed.