Research On The Technology Of Self Cleaning Reverse Circulation Bit

Badger drilling is a frontier technology that complies with today’s oil and gas exploration and development area.Different from conventional drilling technology,there are no drilling rig,no drilling fluid,one drill after drilling,and no drilling and drilling in the process of working.The self cleaning reverse circulation PDC bit is a very important tool in badger drilling technology,and it has to be matched with other badger drilling tools.Based on the work requirements of badger drilling technology,this paper designed two sets of spiral cuttings transport devices:one is single screw chip conveying device,and two is a double helix cuttings transport device.On the basis of the design of the conventional PDC bit and the structure parameters of the screw conveyor,the self cleaning reverse circulation PDC bit is designed,and the strength analysis of the bit is carried out with the finite element software.Based on the dynamic equilibrium condition,the force analysis of the debris particles on the wing of the spiral blade is carried out by the single point method.The relationship between the force of the debris particles and the helix angle of the blade and the friction coefficient of the contact surface is obtained.The mechanism of the single spiral cuttings transport and the double spiral cuttings transport is analyzed.The expression of the critical speed of the single screw and the expression of the power,torque and axial force of the double helix chip conveying section are obtained,which provides a reference for the driving motor of the drill.In this paper,the EDEM discrete element method is used to simulate the rock breaking of the PDC bit,which has two kinds of cuttings transport device.The simulation results of different design parameters show that the speed of the cuttings transportation is the fastest when the propeller angle of the propeller of the single screw rod conveyer is 15 degrees.The depth of the spiral groove of the double screw conveying device is 8mm and the pitch of the screw is 21mm,The effect of the cuttings transportation is the best.Through the rock breaking simulation of PDC bit,it provides a valuable reference for the design of bit structure.