Design and feasibility analysis of a fluidic jet oscillator with application to horizontal directional well drilling

The drilling problems on how to reduce the drag and torque in horizontal directional drilling process have become the focused issues for the directional drilling researches. With regard to the heavy drag and torque of drilling tool, low drilling efficiency and high occurrence of drilling accidents, a fluidic jet oscillator is novelly proposed and designed on basis of the combination between percussive rotary drilling and friction reduction technology. In order to avoid the stand pipe pressure while drilling, the feasibility and pressure loss of the oscillator have been acquired by numerical simulations and experimental tests in condition of various pumped volumetric flow rates. In conclusion, the numerical simulation results agreed well with the corresponding experimental tests. The pressure loss of fluidic jet oscillator is almost exponentially varying with the input flow rates. The minimum pressure loss of fluidic jet oscillator is 1.7 MPa while pumped volumetric flow rate is 10 L/s, and the maximum pressure is 5.65 MPa while the flow rates is 18 L/s, which is permissible in horizontal directional well drilling. Allowing for the limitation of pressure loss in directional drilling, the design of fluidic jet oscillator is feasible to horizontal directional drilling to reduce friction and drag torque, which contributes to improving the penetration rate and reservoir development capacity in oil and natural gas well drilling.