Study On Drilling Mechanics Of Rotary Steering Drilling Tool Bit

Rotary steering drilling technology is often used to control well trajectory and effectively improve rock breaking efficiency.As a drilling tool commonly used in steerable drilling,the rock action process of bit is very complex and difficult to predict,which makes it impossible to directly study the stress characteristics and movement of bit in the well.In order to study the mechanical behavior of PDC bit in rotary steerable drilling,the failure mechanism and loading law of PDC bit in rotary steerable drilling are discussed in this paper Based on the geometry theory of bit,the coordinate position of PDC cutting tooth is studied,and the cutting trajectory function of bit is given.On this basis,the influence of well deviation angle and near bit stabilizer on the deflection angle of flexible short joint is studied:Firstly,based on the geometry theory of the bit,the coordinate position of PDC cutting teeth is studied,and the cutting trajectory function of the bit is given.On this basis,the influence of well deviation angle and near bit stabilizer on the deflection angle of flexible short joint is studied.Secondly,the kinematic model of PDC bit under the condition of rotary guided drilling is studied.Based on the analysis of the rock cutting process,the spring is established-damping-The vibration mechanics model of mass is obtained,and the mathematical model of cutting force in drilling process is deduced.According to the established model and simulation process,the system dynamics simulation program is compiled by numerical calculation method based on MATLAB software platform.The influence of bit rotation angle on cutting force in X and Y directions and the relationship between cutting depth and cutting force as well as penetration rate are studied by single variable method.Finally,the rock geometry model is established by using ANSYS software,and interacts with the bit model established by Solid Works to simulate the rock breaking process of the cutting teeth with the pointing angles of ?=0 °,?=2.5 ° and ?=5 ° to determine the influence law of the controllable bending joint pointing angle on the rock breaking efficiency of the bit;and the modal analysis of the bit rock system is carried out under different pointing angles.