【作者】 李秋敏；

【导师】 刘白雁；

【作者基本信息】 武汉科技大学 ， 机械电子工程， 2008， 硕士

【摘要】 自动垂直钻井系统在工作中,由于纠斜动力的需要,导向活套与钻杆需要保持一个相对转速。导向活套在与钻杆连接轴承的摩擦转矩的作用下而随钻杆转动,而井下返程泥浆在通过活套时也会产生阻碍活套转动的反向扭矩,该反向扭矩是平衡摩擦转矩和保证活套与钻杆存在相对转速的一个关键因素。为了对自动垂直钻具导向活套井下泥浆流场特性有更深入的了解,并研究反向扭矩值的大小和影响因素,需要对导向活套井下泥浆流场进行理论和仿真研究。本文首先利用流体力学理论对自动垂直钻具井下流场进行研究和计算,为仿真运算提供必要的理论基础。然后利用CFD软件FLUENT对导向活套井下泥浆流场进行建模和仿真运算。将理论分析、数值运算和实验数据相对比,研究并揭示了泥浆通过活套时的流动特性。计算结果表明泥浆对活套的反向扭矩取决于多种物理因素,如泥浆的流量、导向活套转速等,且只要钻杆转速超过平衡钻杆与活套的摩擦转矩的临界转速,该反向扭矩就可以使活套与钻杆间产生相应的转速差。自动垂直钻具井下泥浆流场的动力学分析对于钻具的井下正常工作有着重要意义。本文利用理论分析和仿真运算深入研究了自动垂直钻具井下泥浆流场的动力学特性,对导向活套在井下的工作状态有了更好的了解和更深入的研究,也为避免导向活套与钻杆同速转动的问题提供了一种解决方案。更多还原

【Abstract】 When the automatic anti-deviation drilling system is in operation ,a relative rotate speed is needed between the steerable sleeve and the drill string to produce essential anti-deviation powers.The steerable sleeve rotates as a result of the friction torque exerted by the bearing connecting the sleeve and the drill string,while the backtracking muds pass through the sleeve and produce a reverse torque preventing the sleeve from rotating,which is a key factor to ensure a relative rotate speed between the sleeve and the drill string.To know more about the characteristics of the down-hole muds in the automatic anti-deviation drilling system and explore the value of the reverse torque and its factors,we need to study the flow field of the down-hole muds both theoretically and with simulation.At first,the flow field of the down-hole muds was analyzed and caculated with hydrodynamic theories,providing the essential foundation for the subsequent simulation.Then the CFD software Fluent was used to model the flow field of the down-hole muds,and explore the flow characteristics.The theoretical analysis,the simulation results and the experimental figures were studied by contrast and the characteristics of the down-hole muds were found out.The simulation results indicated that the value of the reverse torque depends on several factors such as the mud flux, the sleeve rotate speed and so on ,and as long as the rotate speed of the drill string exceeds the critical rotate speed , the reverse torque by the muds to the sleeve is sufficient to produce a relative rotate speed between the sleeve and the drill string.The dynamic analysis of the flow field of the down-hole muds in the automatic anti-deviation drilling system is very important to the regular operation of the automatic anti-deviation drilling tools.The characteristics of the down-hole muds in the automatic anti-deviation drilling system were studied both theoretically and with simulation,the operation condition of the steerable sleeve was explored and analyzed,and a solution to preventing the steerable sleeve and the drill string rotating with identical speed was advanced.更多还原