The Working Characteristics And Experimental Study Of Jet Oscillating Tools

In the face of the sharp increase in energy demand,the global petroleum and natural gas production capacity is relatively insufficient,and the supply of petroleum and natural gas energy is becoming increasingly tense.Therefore,the exploration and development of unconventional oil and gas resources such as deep oil and gas,shale gas,coalbed methane and gas hydrate have attracted people’s attention.Horizontal well,extended reach well and complex structural well are the main forms of production well at this stage,and the important problem in the drilling process is the problem of large frictional resistance.The jet oscillation tool proposed in this paper is a new type of downhole vibration tool,which uses the jet wall attachment effect to work.It has no moving parts and elastic components inside,and can be used for long-term operations in harsh environments such as high temperature,and can reduce the friction and improve efficiency in horizontal well and extended reach well.In this paper,drilling engineering,computational fluid dynamics,mechanical system dynamics and experimental testing are used to study the working mechanism and characteristics of jet oscillation tools:Firstly,based on the existing research on vibration drag reduction tools and theory,the overall design scheme and working principle analysis of the jet oscillation tool are completed.The structural design of the two key parts of the jet element and the shock absorber are respectively carried out,and the processing drawings and the three-dimensional mode of the jet oscillation tool are drawn.Based on this,the stiffness calculation model of the shock absorber is established,and the dynamic stiffness and static stiffness characteristics of the rubber and the key influencing factors are analyzed.The computational fluid dynamics(CFD)method is used to simulate the complex turbulent flow inside the jet oscillation tool,and the flow characteristics,switching mechanism and entrainment effect of the internal fluid of the tool are qualitatively studied.Furthermore,the dynamic changes of the flow velocity and pressure field at different positions inside the tool and the single factor influence of the flow parameters on the working characteristics of the jet oscillation tool are analyzed.The parameters such as the flow velocity,pressure drop,frequency and axial force of the tool can be obtained.The axial dynamics model of the drill string system in the horizontal well section is established,and then the working performance and vibration drag reduction characteristics of the jet oscillation tool are studied by analyzing the model.The results of the vibration displacement and vibration velocity of different nodes in the drill string system under different input flow rates are obtained,and the influence of the jet oscillation tool on the vibration drag reduction effect at different installation positions is obtained.It can be seen that the vibration displacement,vibration velocity and vibration frequency of the jet oscillation tool are positively correlated with the input flow parameter,and the farther away from the position of the oscillation excitation,the more the attenuation.The working characteristic parameters of the jet oscillation tool are tested by a pressurizable test bench.The test results include the vibration displacement,acceleration,frequency,working pressure drop,axial vibration force and other parameters of the tool under different input flow conditions,and the test results are compared with the numerical simulation and theoretical calculation results.The correctness of the simulation and theoretical calculation models is verified,and the performance is further tested.In summary,this paper aims at the structural design,performance simulation analysis,vibration drag reduction characteristics and bench experimental test of the jet oscillation tool for horizontal well drag reduction,and obtains the variation of the working characteristics of the jet oscillation tool.The applied method and the obtained results can provide some theoretical guidance for the new drilling tool design and directional drilling technology.