Study On Rock Breaking Force And Energy Transfer Law Of Sonic Drilling System

Sonic drilling is to use the longitudinal vibration of the drill string to achieve fast and effective drilling.Traditional sonic drilling is mainly for environmental sampling,and is mainly suitable for drilling in pure soil.However,pure soil drilling cannot be completely realized,and occasionally rock formations will be encountered,so sonic drilling must have a certain rock breaking ability.This paper mainly studies the sonic drilling system in the rock formation,through the establishment of three kinds of sonic drilling system physical models,and then solve the response of the system under various drilling parameters.Firstly,the discrete model of continuous rock impact by sonic drilling system is established,and the bifurcation relationship between the weight on bit and the amplitude of exciting force and the average progression per period is obtained,and the bifurcation relationship between the frequency of exciting force and the bit speed shows the period-doubling.Secondly,a single rock impact model of the sonic continuous system was established,and the maximum rock breaking force and the rock breaking energy utilization rate were used to evaluate the rock breaking capability of the sonic drilling system under the linear bit-rock model.The changing surface diagram of the maximum rock breaking force that can be achieved under the changing drilling depth within the range of working frequency is obtained.And the curve of the energy utilization ratio of rock breaking with the change of drilling depth at each resonance stage.Finally,the model of continuous sonic system impacting rock is established,and the dynamic behavior of the system is further studied.In the last chapter,the influence of the change of drill string material and cross-sectional area on the maximum rock breaking force and the energy utilization rate of rock breaking is studied,and the steel drill string with larger cross-sectional area has better performance.This paper lays a foundation for exploring more complex theory of rock breaking by vibration impact.