方钻杆旋塞阀失效分析与优化设计

发布时间：2018-01-11 01:13

本文关键词：方钻杆旋塞阀失效分析与优化设计　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：钻井新技术正在快速发展,也广泛的应用于各种复杂地层,为了安全优质钻井,降低钻井成本,防止井涌、井喷等事故的发生,必须把井控技术作为研究和发展的重要内容。作为钻柱内防喷系统中关键的内防喷工具,方钻杆旋塞阀是失效最频繁的一种,其性能优劣、寿命长短及工作的可靠性直接影响着井场人员和财产的安全。因此,结合现场旋塞阀的失效形式以及研究现状,对旋塞阀的失效原因进行分析研究,在此基础上对旋塞阀进行优化设计,提高旋塞阀的可靠性和寿命,保证钻井的安全。本文以φ168方钻杆下旋塞阀为研究对象,进行了以下几个方面的研究工作： (1)对方钻杆旋塞阀的现场失效案例进行统计,总结其主要失效形式为：阀体强度失效、密封失效以及转动失效。从静力学和有限元仿真两方面分析了阀体受拉、扭作用下的强度；从密封比压方面分析了旋塞阀的密封机理以及失效原因；对阀芯和旋钮进行受力分析,推导出阀芯与上阀座之间的摩擦扭矩以及旋钮与阀体旋钮孔之间的摩擦扭矩公式。 (2)推导旋塞阀流道开度的计算公式,分析了影响流道开度的主要因素—阀芯关闭角度、阀芯半径以及流道半径,探讨了流道开度随各因素的变化趋势。建立了旋塞阀不同开度下的流场几何模型,采用CFD计算流体力学软件进行了流场数值模拟。其模拟结果表明：阀芯关闭角度、钻井泵排量对旋塞阀的流场影响很大,钻井液固相颗粒直径和固相体积分数对流场的影响较小。结合流道开度影响因素分析和流场模拟结果,分析了其失效与内部流场的关系,提出了旋塞阀优化改进的方法,给出了旋塞阀的现场使用建议。 (3)建立了旋转系统(旋钮、拨块、阀芯以及上阀座的组合)的三维模型,采用ANSYS Workbench有限元分析软件模拟旋塞阀在不同工况下,阀芯转动的瞬间,各零件的应力分布、变形分布以及阀芯和上阀座之间的摩擦扭矩变化规律,找出旋转系统中各零件的薄弱点,分析旋塞阀失效与各零件应力变形的关系。将摩擦扭矩的仿真结果与理论计算结果对比分析,验证摩擦扭矩计算公式的准确性。 (4)以第四章旋塞阀旋转系统中的薄弱点(旋钮和拨块)为优化对象,通过正交试验方法、降半梯形分布隶属函数和数学综合加权法,分析了各设计变量对零件应力变形的影响程度,得出了最优设计方案。优化后的结构减小了旋钮、拨块和阀体接触之间的摩擦系数,降低了旋塞阀的操作扭矩。
[Abstract]:New drilling technology is developing rapidly, and is widely used in various complex formations, in order to safety and high quality drilling, reduce drilling costs, prevent wellbore, blowout and other accidents. Well control technology must be regarded as an important content of research and development. As a key internal blowout prevention tool in drill string internal blowout prevention system, square drill pipe plug valve is one of the most frequent failure, and its performance is good and bad. The length of life and reliability of work directly affect the safety of personnel and property in the well site. Therefore, combined with the failure form of field piston valve and the status quo of research, the failure reasons of plug valve are analyzed and studied. On this basis, the optimization design of the plug valve is carried out to improve the reliability and life of the plug valve and to ensure the safety of drilling. In this paper, the 蠁 168 square drill pipe under the plug valve as the research object, the following aspects of the research work: The main failure forms are summarized as follows: body strength failure. Sealing failure and rotation failure. The strength of the valve body under the action of tension and torsion is analyzed from static and finite element simulation. The sealing mechanism and failure reason of the plug valve are analyzed from the aspect of sealing specific pressure. The friction torque between the spool and the upper valve seat and the friction torque between the knob and the valve body knob hole are derived. (2) the formula of flow opening of plug valve is deduced, and the main factors that influence the opening of flow channel are analyzed, such as the closing angle of valve core, the radius of valve core and the radius of runner. The variation trend of flow opening with various factors is discussed, and the geometric model of flow field under different opening of plug valve is established. The numerical simulation of the flow field is carried out by using CFD computational fluid dynamics software. The simulation results show that the flow field of the plug valve is greatly affected by the valve core closing angle and the drilling pump displacement. The influence of flow field on the diameter of solid particles and volume fraction of solid phase in drilling fluid is small. The relationship between the failure and internal flow field is analyzed according to the analysis of the influencing factors of flow channel opening and the results of flow field simulation. The optimization and improvement method of the plug valve is put forward, and the suggestions for the field application of the plug valve are given. A three-dimensional model of the rotation system (knob, dial block, spool, and upper seat combination) has been established. The ANSYS Workbench finite element analysis software is used to simulate the stress distribution of the piston valve in the moment of the spool rotation under different working conditions. The deformation distribution and friction torque between the spool and the upper valve seat are changed to find out the weakness of the parts in the rotating system. The relationship between the failure of the plug valve and the stress and deformation of the parts is analyzed. The accuracy of the formula for calculating the friction torque is verified by comparing the simulation results of friction torque with the theoretical calculation results. Taking the weak points (knobs and blocks) in the rotary system of 4th chapter plug valve as the optimization object, the membership function and mathematical comprehensive weighting method of reducing half trapezoidal distribution are adopted by orthogonal test method. The influence of various design variables on the stress and deformation of the parts is analyzed and the optimal design scheme is obtained. The optimized structure reduces the friction coefficient between the knob, the drawing block and the valve body, and reduces the operating torque of the plug valve.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE927.9

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