Study On Negative Pressure Pulse Jet Assisted Drilling Technology

The multiple parameters of the bottom hole negative pressure pulse have different influence on the drilling of the bit.This paper focuses on the influence of these parameters on the drilling and drilling.According to the characteristics of the fluidic channel and internal fluid,the unsteady heat conduction equation based on the use of computer language Matlab simulation,simulation calculation of different drilling rock formation in the process of package and negative pressure effect of pulse propagation characteristics and the relationship between.Set the duration for a negative pressure drilling MS,research shows that within this range,the triangular wave pulse value is smaller than the same pulse square wave continuation value in negative pressure continuous underground,the relationship between pulse square wave can promote the efficiency of drilling,the relationship between the parameters of each interval values were selected based on the fluctuation frequency interval the time interval is 55 ~ 105 Hz,1.5 ~ 2.5ms pulse wave has good effect for footage.By changing the shape of the channel and the channel shape of the modulator,a constant nozzle outlet diameter design experiment was carried out to study the effect on the drilling performance.The experimental results show that with the increase of conical nozzle necking,negative pressure impulse loss increases with the increase of the inlet and outlet port;the trapezoidal nozzle diameter ratio,negative pressure pulse value loss.On the basis of the above research,the experiment of negative pressure pulse jet assisted drilling is carried out.The simulation results show that the auxiliary drilling speed with bottom confining pressure increased first and then decreased with the increase of the negative pressure pulse;pulse pressure value;these effects can improve drilling efficiency greatly,the application prospect of immeasurable.