The effect of the structure of end-face sealed rotary valve on pulse pressure

During the drilling of structurally complex wells, hydraulic oscillator can reduce the wall friction significantly and increase the rate of penetration (ROP).And pulse pressure generating unit is one of its important components.In this paper, pulse pressure was numerically simulated using CFD simulation technology based on three structural parameters of end-face sealed rotary valves, i.e., end-face open angle (α), inner and outer radius of open arc (R and r) and installation clearance (h).Then, the effect laws of structural parameters on the form and amplitude of pulse pressure wave were investigated, and the regression equation between pulse pressure and valve open area was established by means of regression analysis.It is indicated that the structural parameters and installation clearance of this series of valves affect the peak pulse pressure and the range of high-pressure band width by changing the flowability of fluid in flow channels, while the change laws of pulse pressure wave form is basically unchanged.The effect of end-face open angle (α) on the width of high pressure pulse is obvious.Inner and outer radius of open arc (R andr) have stronger effect on the extreme pulse pressure, and lead to irregular fluctuation locally in the pulse pressure curve.Installation clearance (h) mainly affects the high pressure amplitude.Finally, an empirical formula for the design of pulse pressure of hydraulic oscillator was provided, and it can be used as the reference and guidance for the study on hydraulic oscillators.