| At present,during the development and drilling of oil and gas resources,the types of oil wells are mainly deep wells and ultra-deep wells.In the drilling process of deep well,with the increase of well depth,the downhole formation tension and rock resistance will continue to rise.At this time,the cutting tooth section of the bit will bear a large load,resulting in the damage of the bit structure,thus reducing the life of the bit and other drilling tools in the downhole and affecting the drilling efficiency.In the face of this problem,in recent years,many researchers at home and abroad began to adopt the technology of hydraulic rotary percussive drilling traditional rotary drilling Based on the combination of high frequency axial impact rock breaking,effectively solve the deep well drilling problem,greatly improve drilling efficiency,reduce production costs.However,the actual test results show that there are still many problems such as unstable performance,insufficient impact work and short service life in the process of drilling under complex working conditions.By comparing the working performance and structural characteristics of several kinds of hydraulic impactors at home and abroad,combining the characteristics of large impact force and stable working performance of dual-acting hydraulic impactors,this paper has developed an innovative reaction hydraulic impactor with a diameter of?172mm,aiming at solving the deep-seated problems the mining problem of the partial reservoir.By consulting the working parameters of the turbine drilling tool of the same size,the working flow range is set to 22-36L/s,According to the relevant theory calculation and combined with the engineering software simulation analysis,the working performance and structural parameter optimization of the newly designed hydraulic impactor are studied by follow 4 aspects:(1)The overall design of the reaction hydraulic impactor was completed.This paper reviews the development of hydraulic impact rotary drilling technology,summarizes the advantages and trends of its application in petroleum drilling,and draws the conclusion that the hydraulic impactor will gradually develop into deep,ultra-deep and complex strata.(2)Process analysis and mathematical modeling of the valve hammer system are completed.Based on the theory of fluid kinematics,the dynamic process of valve hammer system is divided into four stages.Taking hammer and valve as the object of force analysis,the equation of force balance is established.(3)The analysis of the throttling characteristics of the impactor is completed.On the basis of the structural design parameters of the impactor and the stress equation of the valve hammer's uplink process,the required working pressure difference of the valve hammer is calculated to be about 2MPa;and the static pressure simulation calculation of the internal working cavity flow channel of the impactor under 30mm?32mm?34mm?36mm?38mm?40mm six different throttling diameters is carried out by using the Fluent fluid simulation software.Using Origin data processing software to obtain the function relation expression of each flow and pressure difference under the corresponding throttling caliber,and by comparing the simulation data with the numerical value of the theoretical calculation pressure difference,the appropriate throttle size is 36 mm,and the function relation expression of pressure and flow rate is?P=0.00357Q~2.(4)Study on impact characteristics of hammer.On the basis of the performance parameters of the hydraulic impactor on the market at present,the minimum impact velocity of the hammer down is 4.69m/s,combined with the minimum impact work required for rock breaking of the impactor 500J.According to the motion state of the hammer,the impact collision model of the hammer with the rootstock and the limit sleeve is established by using the ADAMS collision simulation software.The system expression is v_f=0.09234-0.10030v_m,which provides theoretical support for the downward impact process of the hammer;combined with the structural material attribute parameters selected by the hammer,the rootstock and the limit sleeve,the mechanical condition of the moving component of the impact process of the hammer is further analyzed by using the Explicit-Dynamic multi-body dynamics simulation calculation software.On the premise of satisfying the structural strength,the final impact velocity of the impact process should not be greater than 3.21m/s,and the final impact velocity range of the downward impact process is 4.69-7.85m/s.(5)Analysis of dynamic output performance and optimization of structural parameters of reaction hydraulic impactor.Using the method of Matlab program design,the corresponding calculation program is compiled according to the motion mathematical model of each stage of the hammer,and the motion characteristic curve of the hammer and the working performance parameters of the impact device are obtained.By changing the different conditions of inlet flow,throttling caliber and spring working parameters,the characteristic parameters such as impact terminal velocity,single impact work and impact frequency of the impact hammer are optimized.Finally,the throttle diameter of the impact device is determined to be 30 mm,the working flow range is20-30.85L/s.Under this condition,the output impact of the impactor frequency is3.94-5.92Hz,the maximum single impact work can reach 932J,belongs to the low frequency high impact work drilling tool,which is suitable for the downhole working condition with high rock hardness in deep and ultra deep wells. |
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