Research On Mechanical Properties Of Underground Electric Drills

In the oil drilling exploration field of deep wells and ultra-deep wells,compared with other hydraulic drive tools which are used commonly,the underground electric drill tool researched in this paper which provides drilling power for the drill bits by the underground motor through the cable when it operates,and it is hardly affected by those factors,like its operating depth,location and drilling mud,because the mechanical energy can be converted from electric energy directly.The development of underground electric drill technology lays the foundation for the automation of drilling process,so that it is deserved high attention in the oil exploration industry.Ensuring the safety performance of underground electric drill during its actual use process can improve drilling efficiency and reduce the cost of drilling.According to the special nature of the working environment of the electric drill tool,the dynamic analysis of underground electric drill system and the finite element analysis of sevral important components which influence the working life of the drilling system deeply are carried out respectively.The main work completed are described as follows:(1)Analyzing the development status of domestic and foreign electric drill tools,the current types of underground electric drill tool were enumerated.And the overall structure of electric drill tool was designed according to its working principle.At the same time,the main parameters of electric drill tool:power,voltage,torque,drilling pressure,reducer transmission ratio,were determined,thus the output characteristic of downhole motor was obtained.(2)The downhole torque and the transmission direction of drilling pressure were gained through mechanical analysis,and the finite element analysis and calculation model of the electric drill’s vulnerable parts,the motor shaft,the stator shell and the output transmission shaft,were established by three-dimensional modeling software.To ensure the safety performance of drilling tool,Using finite element analysis software ANSYS,the strength,fatigue strength,modal and linear stability analysis were carried out,(3)Using the Lagrange equation,the dynamic analysis of downhole electric drilling system is carried out.The finite element analysis of the key parts in the fourth chapter shows that the design of the electric drill tool is easy to damage under the action of torque and drilling,and the strength,fatigue and stability of the component are required.The fifth chapter in the torsional force under the action of downhole drill system for dynamic analysis,shows that from the angular velocity curve,motor running stability,the variation of the motor shaft and the speed reducer and the bit angular velocity output curve is similar,but the angular speed fluctuation range greater than the bit speed reducer,reducer is greater than the motor shaft;the bearing from the spring torque first torsion spring bearing torque changes less than second torsion springs under external torque variation.It can be seen that under the action of torsional force,the influence of the fluctuation drilling pressure on the reducer and the motor shaft is gradually reduced by the equivalent torsional spring.