Numerical Simulation Study On Effect Of Impact Load Characteristics On Rock Breaking Efficiency Of Drill Bit

As the main technology to improve the efficiency of bit rock breaking,percussion drilling technology has been widely used in deep well drilling in hard formations.However,due to the extremely complex stress conditions during drilling of deep wells,it is difficult to simulate complex underground wells during the experiment.Because of the stress conditions,how to improve the efficiency of rock breaking by the rotary drilling technology,how much can be improved,and what types of strata are used are insufficiently understood.Therefore,the use of numerical simulation software to study the mechanism of rock breaking under the conditions of rotary drilling has become the main research means.Based on the ABAQUS software,this paper establishes a model of single-cutter teeth and full-scale PDC bit rock breaking,and compares the characteristics of single-cutter under the action of static and dynamic loads and pure static load.The influences of drilling parameters such as drill bit speed,drilling pressure and rock type,dynamic and static load combinations,impact load frequency,and impact load waveform on the rock breaking effect were studied.The results show that the stress of the cutting teeth under the action of dynamic and static loads causes the tensile stress and compressive stress of the rock to alternate,which is conducive to the generation and expansion of cracks.Therefore,the efficiency of rock breaking can be greatly improved.With the increase of on-press weight,the efficiency of rotary drilling improves the efficiency of the drill bit gradually;the best bit speed can achieve the best effect of improving the rock breaking efficiency of rotary drilling.The impact load characteristic parameters have a significant influence on the rock breaking efficiency of the drill bit.Under the condition that the total load is equal,the optimal dynamic and static load combination can maximize the rock breaking efficiency;there is an optimal impact load frequency,which improves the rock breaking efficiency of the drill bit.The effect is the greatest;the impact load waveform has an impact on the rock breaking efficiency of the drill bit,and the more gradual loading of the load,the higher the rock breaking efficiency of the drill bit.