The Study Of Numerical Simulation On The Bottom Hole Flow Field And The Design Of PID Bit

With the continuous depletion of shallow oil and gas resources in our country,it is an important work to search for oil and gas exploration and development in deep hard formations and complex geological conditions.Particle impact drilling technology is used in drilling,breaking the traditional way of breaking rock,which is considered to be the most effective method to improve the drilling speed of deep hard formations at present.PID bit is an important part of the particle impact drilling system,which is directly related to the drilling efficiency and drilling cost.By means of numerical simulation and experimental study,this paper studies the flow field of PID bit and the rock breaking law of single jet particle.First of all,the foreign latest generation of 6?"particle impact drill bit for the establishment of physical model,the DPM model,field working conditions at the bottom of the velocity field and pressure field distribution simulation,can satisfy the particle impact drilling rock breaking,change bit nozzle spray angle of 0°to 30°,variation of jet high pressure and high speed overflow area,and ultimately come to the conclusion,with the spray angle increases effective bottom hole jet impact pressure area is reduced,and with the increase of jet angle,jet tangential velocity increases,the area with high speed and efficient overflow jet in the increase.In the actual drilling process,the jet angle of the nozzle can not too large,on the one hand,particle impact drilling on the bottom of the impact of high-speed particles breaking rock,the injection angle is too large,particle tangential velocity is too large,resulting in hydraulic energy utilization rate decreased,on the other hand,larger injection angle,resulting in drilling fluid of sidewall erosion speed greatly,resulting in the hole is too large,wellbore instability and other hazards.Secondly,based on the principle of similarity design bit used in particle impact test,using the method of single factor variable,with the rock breaking volume and the depth of the rock breaking effect of standard,on the jet parameters including,spray distance,spraying angle,particle volume fraction,injection time and pump displacement of rock breaking effect influence were studied,for particle impact drilling bit design provides based on indoor tests.Finally according to the rock breaking experiment results and numerical simulation,and bit nozzle arrangement optimization,the 8?"PID bit is designed.