Working Position Design And Optimization Of Vibrating Friction-reducing Tools In Directional Well

In the process of horizontal well and extended reach well drilling,the axial friction of drill string is inevitable.It May cause weight stacking and helical buckling.Vibrating frictionreducing tools can produce continuous low frequency and low amplitude axial vibration of drill string and downhole tools.This can break the static friction and eliminate the torsional vibration,which will solve the problem of weight stacking.Vibrating friction-reducing tools can be installed in any position of the drill string.But in order to maximize the effect,it is necessary to design and optimize the position according to the actual working conditions.So it is needed to study the theory of reasonable working position of vibrating friction-reducing tools in the drill string.And at the same time,we need to take into account the working parameters and field working condition parameters.Then we can form a complete theoretical system for the application of the tool.In this paper,firstly,indoor parameter optimization experiment of SLZDQ172 hydraulic oscillators is carried out and we can get optimal output parameters of the instrument.Then the vibration model of downhole drill string is established according to the working condition of the hydraulic oscillators.At the same time,we take into account the drilling mud viscosity,density,angle of the well,the output frequency and impact force of the hydraulic oscillator and other factors,and we analysis of the impact of the parameters on the performance of the tool.Finally,we design the tool position diagram combined with the work parameters,which is convenient for the application of the tool in the field.The results show that the tool friction-reducing effect is mainly influenced by the vibration frequency and impact force of the tool.What's more,the angle of the well and the position of the tool also effect a lot.In addition to reducing the friction of the drill string,the hydraulic oscillator can absorb the irregular vibration of the drilling bit and assist rock breaking when it is installed in heavy weight drill pipe.According to the theoretical analysis,we can find the reasonable position of the hydraulic oscillator.By the relevant position diagram,we can accurately design and optimize of the position of the tool,which will improve the using effect of hydraulic oscillator.