| The work in this paper was based on the National High-Tech Research & Development Program (863 Program) project"The Research on Interrelated Technologies of Horizontal Well Inspection"and cross research program"The Research on the Mechanism and Control Technology of a Telescopic Horizontal Well Tractor".The detection of the horizontal wells is very useful to improve the oil production and the efficiency. To develop the technology of the inspection of the horizontal wells, it's great significant to develop the machines used for sending the detection instruments into the horizontal wells. To meet the need of the horizontal well inspection, by studying the existing horizontal well tractors and the in-pipe robots based on inchworm mechanism , a telescopic horizontal well tractor based on the mechanism of single-direction movement was proposed。The tractor proposed was designed in modular structure; its minimum diameter is 54mm and can adapt the change of the pipe diameter between 140mm to 180mm. The tractor has a hauling capability of over 2000N, with the moving speed of over 6m/min. In a word, it can meet the horizontal well tractor's demand of pony size, heavy load and modularization.Single-direction movement mechanism is the most important part on the tractor. It contains the support arms driven by screw pairs to adapt the diameter change and the self-locking cams to produce heavy locking force. Taking the Single-direction movement mechanism as the subject, some results were achieved as follows:1) On the basis of the virtual prototype technology and dynamics analysis software, the moving principle and all the factors that may have influence on the moving capability of the tractor had been analyzed and simulated in the virtual design and analyse. Through the simulation and analyse, the influencing factors were more clear and it was very important to improve the tractor's moving capability;2) The support arm of the single-direction movement mechanism was designed and analyzed. To solve the arm's problems of singularity and huge start force, a mechanism with bevel and idler wheel was proposed. The simulation and analyse showed that the design could solve the problem of singularity effectively, and also the start force could be reduced obviously, which could bring an increase of efficiency.3) The cam, key part of the single-direction movement mechanism, was designed and analyzed. The profile of cam, which made the cam self-locked and adapt the diameter change of the well pipe, was designed.4) The ultra-high pressure seal structure of the system was designed, which made the tractor adaptable to the very bad environment of horizontal wells.Finally, on the basis of the study on single-direction movement mechanism, the model machine of the tractor was made, and the prototype test was done. The test result proved that the principle was right and the structures was reasonable .which meant that telescopic horizontal well tractor based on the mechanism of single-direction movement we proposed could be realized. |
