钻井泵泵阀系统磨损与失效分析研究

发布时间：2018-11-14 12:21

【摘要】：钻井泵是钻井过程中的重要设备,用于输送井底循环钻井液。在钻井泵的工作过程中,由于承受较大而不稳定的载荷,工作环境十分恶劣。正是恶劣的工作环境及自身工作原理,导致钻井泵的液力端存在着极易损坏的部件,包括活塞、缸套、泵阀系统(阀体、阀座、阀弹簧、阀橡胶密封圈和密封圈压板等)。钻井泵易损件的存在,严重影响钻井泵的工作效率,严重制约着生产效率的提高。针对上述问题,本文对常见易损件之——泵阀系统的失效形式进行分析,确立了泵阀系统的主要失效机理；利用MATLAB软件对阀体的运动微分方程进行求解,将求解的结果作为初始条件,对泵阀系统开展了流场仿真分析和冲击动力学仿真分析；并就不同阀座类型的泵阀系统进行了脉冲循环应力作用下的疲劳寿命分析研究；最终提出了在原泵阀系统的基础上的改进方案,并进行了初步分析研究,以提高泵阀系统的冲击磨损与冲蚀磨损性能。在上述研究过程中,取得的主要成果包括： (1)对泵阀系统常见失效形式进行研究,并通过与各磨损机理进行对比发现,泵阀系统主要的失效机理包括冲蚀磨损、冲击磨损及磨料磨损等； (2)通过对阀体的运动微分方程进行求解,求解出阀体运动的升程曲线,可以看出其近似呈抛物线型或纺锤型,且阀体锥角、冲次等因素对阀体的运动,都有一定的影响,但影响方式和程度不同； (3)在泵阀系统流场中,阀隙处的流场速度较大,且阀隙处流场方向并不是完全沿阀隙方向的,而是与壁面之间呈一定角度。同时由于流场分布的不均匀性,在流场中液缸靠近阀体位置、阀体上表面及液缸端盖附近产生较强的漩涡,漩涡将使钻井液速度增加,从而带动钻井液中的粒子对泵阀系统及液缸相应部分产生强烈冲蚀作用。泵阀系统内的流场分布影响因素包括阀体锥角、冲次等。冲击粒子的大小、形状、冲击速度、角度等对粒子与靶材间的冲蚀作用也有着重要的影响； (4)由于阀体和阀座之间巨大的冲击力作用,将在阀体和阀座上产生较大的应力集中,经过多次疲劳冲击后,将导致应力冲击部位因发生冲击疲劳磨损而损坏。同时橡胶密封圈厚度、阀体锥角、阀座外锥角、阀座类型等对泵阀系统的冲击特性存在影响； (5)提出了阀体与阀座之间采用球面接触和采用缓冲液缸结构两种结构改进方案,两种结构的泵阀系统分别具有减小冲蚀磨损与冲击磨损作用。本文从泵阀系统的主要失效形式出发,建立了一套较为完善的对钻井泵泵阀系统磨损与失效进行仿真分析的方法,该方法对于后续钻井泵泵阀系统的结构设计和参数优选等具有一定的参考价值。
[Abstract]:Drilling pump is an important equipment in drilling process, which is used to transport bottom-hole circulating drilling fluid. In the working process of drilling pump, the working environment is very bad because of the large and unstable load. It is the poor working environment and working principle that cause the hydraulic end of the drilling pump to be easily damaged, including piston, cylinder liner, pump valve system (valve body, seat, valve spring, valve rubber seal ring and seal ring pressure plate, etc.). The existence of perishable parts of drilling pump seriously affects the working efficiency of drilling pump and restricts the improvement of production efficiency. In view of the above problems, this paper analyzes the failure form of the pump valve system, which is one of the common easily damaged parts, and establishes the main failure mechanism of the pump valve system. The differential equations of motion of the valve body are solved by MATLAB software. The results of the solution are taken as the initial conditions and the flow field simulation analysis and the impact dynamics simulation analysis of the pump valve system are carried out. The fatigue life of pump valve system with different valve seat types under the action of pulse cyclic stress is studied. Finally, the improvement scheme based on the original pump valve system is put forward, and a preliminary analysis is carried out to improve the impact wear and erosion wear performance of the pump valve system. In the above research process, the main achievements are as follows: (1) the common failure forms of the pump valve system are studied, and the main failure mechanism of the pump valve system is found to include erosion wear by comparing with each wear mechanism. Impact wear and abrasive wear; (2) by solving the differential equation of motion of the valve body, the lifting curve of the body motion can be solved. It can be seen that the valve body is approximately parabolic or spindle-shaped, and the movement of the valve body is affected by such factors as the cone angle, punching and subtraction of the valve body. All have certain influence, but the influence way and degree are different; (3) in the flow field of the pump valve system, the velocity of the flow field at the valve gap is large, and the flow field direction of the valve gap is not completely along the valve gap direction, but is at a certain angle with the wall surface. At the same time, due to the uneven distribution of the flow field, the cylinder near the valve body position in the flow field, the upper surface of the valve body and near the end cover of the cylinder will produce a stronger swirl, which will increase the drilling fluid speed. Thus, the particles in the drilling fluid have strong erosion effect on the pump valve system and the corresponding parts of the cylinder. The influencing factors of the flow field distribution in the pump valve system include the cone angle of the valve body, the impingement and so on. The size, shape, impact velocity and angle of impact particles also have an important effect on the erosion between particles and targets. (4) due to the great impact force between the valve body and the valve seat, there will be a greater stress concentration on the valve body and seat, which will lead to the damage of the stress impact part due to impact fatigue wear after repeated fatigue impact. At the same time, the thickness of rubber seal ring, the cone angle of valve body, the outside cone angle of seat and the type of valve seat have influence on the impact characteristics of pump valve system. (5) two improved schemes of spherical contact between valve body and valve seat and buffer cylinder structure are proposed. The two kinds of pump valve system have the function of reducing erosion wear and impact wear respectively. Starting from the main failure forms of the pump valve system, a set of more perfect methods for simulating the wear and failure of the drilling pump valve system are established in this paper. This method has certain reference value for the structure design and parameter selection of the pump valve system of the follow-up drilling pump.
【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】：TE924

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