Numerical Simulation And Experimental Study Of Reverse Fluidic Oscillator Tools For Friction-reduction

Shale gas is a clean energy with large reserves,wide distribution and high efficiency,it has huge potential for exploitation.The extended reach well offers the potential to significantly increase the efficiency of extracting shale gas.The high friction between the drill pipe and the well has limited the widespread use of the extended reach well.The addition of axial vibration tools to the bottom hole assembly is an effective solution to reduce the high friction in the extended reach wells.One of the most effective axial vibration tools is the fluidic flow modulating tools.Its no moving part design reduce the length of tool and make it compact,robust and show resistance to extreme conditions.However,high pressure drops and complex operating mechanisms are common problems fluidic flow modulating tools.In order to solve the above problems,a series of friction-reduction tools are proposed,and numerical calculations and experimental studies are carried out.The main conclusions of this paper are as follows.(1)The short length,no moving parts,all-metal reverse fluidic oscillators tools for friction-reduction are developed.The designed single and multi-cavity configurations optimise the oscillation frequency and pressure drop.(2)The working mechanism of the fluidic oscillator was explained based on the study of the switching and attached of the jet,and the growth and dissipation of the vortex.(3)The effects of fluid and particle parameters on tool performance are analyzed,and the results show that particles accumulate inside the tool and reduce tool performance,and that the content of solid phase needs to be controlled in engineering practice.(4)The structure parameters affect the tool performance.The pressure drop can be reduced by increasing the outlet size and reducing the nozzleto-splitter distance,and the oscillation frequency can be reduced by increasing the outlet size and nozzle-to-splitter distance to meet different engineering requirements.(5)The locations susceptible to erosion are the nozzle,splitter,control port,outlet and bottom.The dynamic erosion characteristics under the influence of the periodically switching jet are revealed.The amount of erosion at the outlet and splitter increase in a fluctuating manner.