注水管柱测量短节的机械结构设计与分析

Mechanical structure design and finite element analysis for measuring nipple in injection string

注水是提高油田采收率和稳定油田产能的重要工艺措施。为了弄清注水管柱在井下不同工况下的应力及轴向变形规律,提高注水管柱的寿命和安全可靠性,需要测试注水管柱的受力状态,为此设计研制了一种基于应变测试技术和储存回放模式的测量短节。介绍了注水管柱测量短节的工作原理及控制流程,详细阐述了测量短节的结构设计,对测量短节主轴体的强度进行了有限元分析,并对短节内部粘贴电子仪器表面所选取的线性化路径进行了应力分析,分析结果表明：该测量短节在不同注水工况下均能满足注水管柱测试性能要求,最佳粘贴电子仪器的位置位于短节密闭舱室内部80~300 mm之间,为测量短节的设计和使用提供了理论依据。

Water injection is a significant process to improve oil recovery and make oil production-capacity stable. In order to find the rules of stress and axial deformation of injection string in downhole under different conditions, improve life and safety of injection string, as well as test the stress state of injection string,a special measuring nipple was developed based on the strain measurement and storage playback. The working principle and control process of the measuring nipple were introduced and the me- chanical structure was described in detail. In addition, the finite element method was used to analyze the strength of the inner sleeve of measuring nipple and the stress of linear path in the nipple surface for pasting electronic instrument. The result shows that the strength of measuring nipple satisfies the requirements of different injection conditions and the best position of pasting electron- ic instrument locates at 80~300 mm inside of the sealed compartment, providing a theoretical basis for nipple design and use.