Experimental and numerical investigation of the novel downhole intensifier controlled by electromagnetic valve

Stress release with rock slotting by ultra-high-pressure water jet is an effective method in reducing rock strength in the bottom hole caused by high in-situ stress in deep formation. The characteristics of duration and frequency of the water jet are vital for forming different grooves to release downhole stress. To improve the duration of the high-pressure water jet and modulate different jet frequency, a kind of downhole intensifier controlled by electromagnetic valve was developed and proposed. The water jet performance and the motion characteristics of the plunger of the intensifier were studied in various input pressure and switch frequency of the electromagnetic valve based on experiments, and a series of numerical simulations were conducted considering the input pressure, stroke, and area ratio of the plunger. The results indicate that the output waveform of the intensifier goes like a square shape. Increasing the input pressure and the area ratio of the plunger can enhance the output pressure while the duration of the peak pressure decreased. The stroke of the plunger shows a significant effect on the duration of the peak pressure and jet frequency. Adjusting the switching frequency of the electromagnetic valve can easily change the duration of peak pressure, which is beneficial for forming grooves with different characteristics. The research is believed to provide an important reference in drilling Engineering for deep and ultra-deep wells.