Experimental Model And Simulation Analysis On Drill Pipe Of The Reconnaissance Drilling

Owing to the advantages of high efficiency, low power consumption, few accidents, long using-life of the bit, and light in weight of the equipment, the turning drilling is widely used in the realm of oil well drilling, water well drilling, China Continent Science Drilling (CCSD), engineering geological investigation, etc. In the actual process of investigation drilling, the forces of the drill string is very complexity, there are many external interference factors, and the natural frequency of the drill string is very low, as a result, it will be easily excited that the vibration modal of the drill string. The vibration of the drill string will accelerate the fatigue and wear of the drill pipe and bit, then the penetration rate will be reduced, consequently increase the cost of the drilling project. So it is very necessary to analyze and study the mechanics performance and dynamic characteristics of the drill string which are used in the actual drilling process, consequently we can get the force and deformation characteristics of the drill string, and find the vibration law of all kinds of drill string under the boundary conditions which are close to the reality.The article takes the drill string as the analysis object, which is used in reconnaissance drilling process, it isn't restricted in some certain kind of specific type in the research, but in fact the intention is to discuss the general law of the drill string vibration. In the article, the FEA simulation model parametrically based on the ANSYS software for drill pipe has strong practicability and currency from special to common, which improve the efficiency of analysis and research greatly and establish the better basic for further analysis and research. At the same time, the factors of pressure and flotage power of the well are considered in the model of the drilling string. Comparing with the existing finite element model of the drilling string, the simulation level is improved.Firstly the article explains the purpose and meaning for the research, analyzes the research situation, the development trend as well as the exiting problem in the world, and point out the main research contents. It introduces the structure, active status and the stress characteristic of the drilling string; moreover makes definitely discussion to the research on model experiment of the drill string. Considering all kinds of boundary condition and actual operating condition, the finite-element simulation model of the drill string is developed, based on the finite-element analysis (FEA) software ANSYS. After that, the article analyzes the whole stress and distortion condition for the drilling string, which will be worked in every different drilling condition, explains its whole stress condition and distortion characteristics, summarizes its general rules of stress and distortion. Using modal analysis technology of ANSYS software to compute out the natural frequency and vibration type of the longitudinal vibration, torsional vibration and transverse vibration during every phase situations for drilling string, we can get a mass of data for the research. The variety rule of the natural frequency of the drilling string was discovered by the way of analyzing the result of modal analysis, and the effect of different factors on the natural frequency has also been discussed. Finally the article summarizes every result for the research, and points out the problem that need to be solved in the future.The optimum design of the drill pipe and reasonable drilling parameter can be well developed based on the data and results in the article, accordingly the using-life of the drill pipe and bit will be also longer.