Research On The Working Mechanism And Dynamic Characteristics Of A Longitudinal-torsional Compound Vibration Tool

When drilling complex wells such as deep wells,ultra-deep wells,and large-displacement horizontal wells,the drill string system always undergoes axial vibration,torsional vibration,lateral vibration and mutual coupling vibration between them,resulting in unstable drilling system.The probability of an accident is greater and will directly increase the economic cost.Therefore,it is of great significance to reduce the harmful vibration of the drill string system,increase the mechanical speed,shorten the well construction period,and ensure the safe operation of the drilling.While studying the theory of the dynamics of the drill string,it is also of great significance to carry out the research on the drilling speed-up tool.Based on this,the innovation of this paper is to design a longitudinal torsional composite vibration tool as the carrier,design and analyze the tool structure and working principle,and study and analyze the kinematics relationship of the tool according to the working principle of the tool.This paper combines the actual working conditions of the drilling to model the axial and torsional drill string system of the tool.Combined with the axial pulse force and torsional impact force generated by the tool,the tool axial vibration speed increase and the stick-slip vibration effect are analyzed.Finally,the tool fluid motion and tool collision are simulated and analyzed,and compared with the theoretical calculation results.The main research contents of this paper are as follows:(1)Based on the investigation of the existing drilling speed-increasing viscosity-slip tool,a longitudinal-torsion compound vibration drilling speed-up tool was designed.The tool structure and working principle are introduced.The tool can generate axial pulse force and torsional impact force,which is of great significance for improving drilling speed and reducing the stick-slip vibration during drilling.In order to ensure the effect of the tool,the turbine powertrain part is calculated and analyzed to determine the relevant structural parameters and performance parameters of the turbine blade.(2)This paper analyzes the motion characteristics of the tool,and establishes the over-flow area and motion model of the disk valve according to the structural characteristics and motion principle of the tool dynamic and static disk valve.This paper also analyzes the tool pressure drop and axial pulse force,and then establishes the torsional motion model and collision model of the tool impact hammer and impact seat,and analyzes the results of the tool kinematics related examples.(3)This paper uses Ansys fluent to simulate and analyze the tool fluid motion,and uses LS-D YNA to simulate the impact hammer impact torque.Compared with the results of the tool kinematics theory,the results show the theoretical results and the simulation results are highly consistent.(4)This paper makes assumptions about the establishment of the drill string system model.and establishes a multi-degree of freedom axial and torsional vibration model of the horizontal well drill string system including tools.Firstly,the axial vibration model of the drill string system is solved and the axial vibration results of the drill string system under different input flow conditions are obtained.Then,the torsion-slip vibration model of the drill string system is solved,and the friction torque of the drill string and the bottom-hole friction model are analyzed to obtain the viscous vibration comparison results with or without tools.At the same time,the influence of the bit motion phase result and the torque result on the stick-slip vibration is analyzed.Finally,the effects of changing the input torque of the drill string system and the impact torque of the tool on the stick-slip vibration of the drill bit are analyzed.In summary,this paper proposes a longitudinal and torsional composite vibration tool to analyze and study the kinematics of the tool,and simultaneously carry out simulation and comparative analysis,and then establish a tool-based longitudinal and torsional dynamics model to analyze the axial vibration effect of drilling string system.And the torsion vibration to reduce the stick-slip effect,the designed tool can provide reference for the drilling speedincreasing and reducing stick-slip technology,and the established theoretical model can promote the development of horizontal well drill string dynamics.