螺杆钻具旁通阀结构性能仿真分析研究

【作者】 张强；

【导师】 李斌；

【作者基本信息】 西南石油大学 ， 机械工程， 2017， 硕士

【摘要】 旁通阀作为螺杆钻具的主要组成部件之一,其工作性能的优劣直接关系到螺杆钻具能否正常工作。旁通阀的使用寿命,对螺杆钻具的使用寿命有着重要的影响。在钻井作业过程中,常常会出现旁通阀的过度冲蚀、刺漏、无法正常开启和关闭等现象,这些都会造成旁通阀无法正常工作,对钻井作业造成很大的影响。因此,本文以(?)172mm规格的螺杆钻具旁通阀为例,采用Fluent软件对旁通阀开启状态和关闭状态的流场特性进行仿真分析,并用离散相模型对旁通阀的耐冲蚀特性进行仿真分析。本文主要完成的工作内容有:(1)在研究螺杆钻具发展现状的基础上,分析和总结目前旁通阀的研究和应用现状,总结存在的主要问题,并提出本文的研究目的和研究计划。(2)对螺杆钻具以及旁通阀的组成结构进行研究,分析了旁通阀的工作力学特点和主要失效原因。(3)建立旁通阀内部流场的三维仿真模型,在并在ANSYS软件完成仿真模型的有限元网格划分。在Fluent软件中,根据螺杆钻具旁通阀内部流场的特点,设置相关的仿真参数。(4)给定不同的钻井液流量,分析了在不同开度和关闭条件下,旁通阀内部流场的特性。仿真结果表明阀芯内部流场存在较大的压力和速度梯度;在旁通阀的侧孔通道内,钻井液的流速较高。并根据仿真结果,提出对旁通阀结构的优化措施。(5)运用离散相模型,仿真分析不同流量、不同含沙量的钻井液对旁通阀的冲蚀特性。仿真结果表明,在旁通阀全开位置时,其受到的冲蚀磨损最为严重;且冲蚀磨损率与钻井液的流量、泥砂含量有关。根据仿真结果,提出旁通阀结构的优化措施。本文结合螺杆钻具旁通阀的样本和实际工作情况,应用CFD软件对螺杆钻具旁通阀开启和关闭状态的流场特性进行分析,并根据仿真结果对螺杆钻具旁通阀的结构进行优化,到达更好地控制旁通阀工作的性能,提高钻井过程工作效率的目的。同时,采用CFD软件中的离散相模型,对旁通阀受到冲蚀磨损最为严重的部位进行结构改进,对于提高旁通阀的使用寿命具有一定的参考意义。更多还原

【Abstract】 As one of the main components of positive displacement motor,the working performance quality of the bypass valve directly related to the normal work of positive displacement motor.The service life of the bypass valve has great effect on the service life of the positive displacement motor.In the process of drilling operation,it can often appear the phenomenon of bypass valve,such as excessive erosion,piercing-caused leakage,may not close and open properly,all of these can cause bypass valve cannot work normally,great effects on the drilling operation.Take the bypass valve of(?)172 mm positive displacement motor as an example,the flow field characteristics of open and close state of bypass valve were simulated and analyzed by using Fluent software,the erosion resistance of bypass valve is analyzed by using discrete phase model.The main work contents are as follows:(1)on the basis of the research of current situation of the development of positive displacement motor,analysis and summarizes the current situation of research and application of bypass valve,summarizes the main problems,and puts forward the purpose of this study and research program.(2)The structural composition of positive displacement motor and bypass valve were studied,the working mechanics characteristics and the main failure reasons of bypass valve were analyzed.(3)The 3D simulation model of the interior flow field of bypass valve was established,the finite element mesh division of the 3D simulation model was completed in ANSYS software.According to the flow field characteristics of bypass valve,simulation parameters were set up in Fluent software.(4)Given the different drilling fluid flow,the interior flow field characteristics of the bypass valve were simulated and analyzed under different opening and closing conditions.The simulation results show that there is a large pressure and velocity gradient in the internal flow field of valve core of bypass valve.The drilling fluid velocity in the side hole channel of bypass valve is much high.And the bypass valve structure optimization measures are put forward according to the simulation results.(5)The drilling fluid erosion characteristics of bypass valve under different flow and sediment concentration by using discrete phase model.The simulation results show that the most serious erosion wear of bypass valve happen in the full open position.And the erosion wear rate associated with the flow,sediment concentration of drilling fluid.And the bypass valve structure optimization measures are put forward according to the simulation results.Combining with screw drill tool bypass valve samples and actual working condition,the application of CFD software for screw drilling tools by-pass valve opening and closing state of the flow field characteristics is analyzed,and according to the simulation results of screw drill tool bypass valve structure optimization,to better control the performance of the bypass valve work,enhance the working efficiency of the drilling process.At the same time,using the discrete phase model in CFD software,the bypass valve is most serious erosion wear parts for structure improvement,to improve the service life of the bypass valve has certain reference significance.更多还原