旋转防喷器胶芯结构分析及优化

旋转防喷器是欠平衡钻井的关键设备,带压作业过程中其密封性能是保证安全生产的重要因素。现有的国产旋转防喷器存在胶芯密封不严以及易发生疲劳损伤失效等问题。鉴于此,利用ABAQUS软件建立了旋转防喷器胶芯动态密封有限元模型,对胶芯预紧工况下和起下钻工况下旋转防喷器的力学性能进行了分析,分别讨论了胶芯硬度和铁芯结构对旋转防喷器胶芯使用寿命的影响。分析结果表明:在带压下钻过程中,胶芯呈轴向拉伸变形状态,起钻过程中胶芯呈向上压缩变形状态,且起钻和下钻工况对胶芯密封性能影响不大,下钻工况的密封性能略大于起钻工况;胶芯材料硬度为80 HA时,胶芯的使用寿命最长;优化改变铁芯结构可使胶芯使用寿命延长。室内密封试验以及现场试验证实了有限元优化结果的可靠性。研究成果对延长胶芯使用寿命和提高油田作业安全具有重要的现实意义。

Analysis and Optimization of Rubber Core Structure of Rotary BOP

Rotary blowout preventer(BOP)is a key equipment for underbalanced drilling,and its sealing performance is an important factor to ensure safety during operation under pressure.The existing domestic-made rotary BOPs have problems such as weak rubber core sealing and prone to fatigue damage and failure.In view of this,the dynamic sealing finite element model of the rubber core of the rotary BOP is established using the ABAQUS software.The mechanical properties of the rotary BOP under the preload condition of the rubber core and the tripping condition are analyzed.The impacts of rubber core hardness and iron core structure on the service life of the BOP rubber core are discussed separately.The analysis results show that during the process of run-in-hole under pressure,the rubber core is in a state of axial tensile deformation.The rubber core is in a state of upward compression deformation during run-out-of-hole.The run-in-hole and run-out-of-hole conditions have little effect on the sealing performance of the rubber core.The sealing performance of the run-in-hole condition is slightly greater than that of the run-out-of-hole condition.When the hardness of the rubber core material is 80 HA,the rubber core has the longest service life.The optimization of the iron core structure can extend the service life of the rubber core.Indoor sealing tests and field tests have confirmed the reliability of finite element optimization,and the research results have important practical significance for extending the service life of rubber cores and improving oilfield operation safety.