Design Research On Drilling String Shock Absorption & Percussion System

The rotary percussion drilling technology have the advantage to raise the hard rock well drilling speed effectively, prevent the borehole deviation in the hard rock or the complicated geologic strata. Because of the down hole drill pressure fluctuate, the drill bit will jump to leave the well bottom, it will make the dill bit and the well bottom produce discontinuous contact. The rotary percussion drilling depend on the impact load affect that the impacter created carrying on the dill bit, it not require the dill bit and the well bottom produce deviate displacement, it needs to lessen the drill pressure fluctuation of the well bottom, the research of vibration absorber and percussion system have a pragmatic value.Firstly, Used the BHA movement condition simulating experiment equipment that according to the alike theories carried on imitating the research of the wellbore down hole drill pressure fluctuate situation in the experimental laboratory. Analyzed the different BHA combines under the different parameter, obtained the amplitude, the frequency and the phase of the down hole drill pressure fluctuation. It provided a related basis for the design of vibration absorber and percussion system. And then designed the drilling string shock absorption & percussion system according to the conclusion of the experiment and the design philosophy , gave the parameter of the impacter and the dished spring part. Analyzed the kinetics of the vibration absorber and percussion system. Studied the drill pressure model of percussion drilling, obtained the percussion frequency should accordant with the drill pressure fluctuation frequency, in this way can display the optimal effect of rotary percussion drilling, averted the energy decrease of energy transfer, at the same time divide the percussion frequency and the base frequency of drill string. Finally used the mechanical imitation software ProE to set up the 3D model of the mechanism, realized the kinematics analysis and the verify of assembling interfere and the movement harmonization, proved the possibility of design vibration absorber and percussion system.