基于ABAQUS旋转防喷器胶芯的非线性有限元分析

Nonlinear Finite Element Analysis of Rubber Core of Rotary Blowout PreventerBased on ABAQUS

旋转防喷器(RBOP)是欠平衡钻井中必不可少的安全保障设备,其中胶芯是旋转防喷器(RBOP)的关键部件和密封单元,其密封性能决定了旋转防喷器(RBOP)的密封能力。研究了旋转防喷器胶芯的工作机理及故障,依据国家标准和专利建立了胶芯的三维模型。通过分析研究,选择了适合胶芯材料的本构模型Yeoh模型,通过橡胶材料的单轴拉伸试验所获得的实验数据,使用ABAQUS软件拟合出本构模型的待定系数;在ABAQUS软件中建立钻杆与胶芯接触的三维力学模型,研究计算在不同井压下,钻杆与胶芯之间的接触压力大小和变形情况,得到了不同井口压力下,胶芯密封压力的变化规律——当井口压力逐渐增加时,胶芯内锥面开始发生变形,变形随压力的增加而增大,同时,内锥面和主密封面接触发生应力集中的现象;分析了井口压力为0时,钻杆接头通过胶芯内孔时,胶芯接触压力情况,得到了接触压力在胶芯内锥面各个节点的变化规律,为胶芯的失效分析和设计制造提供了理论依据。

The rotaty blowout preventer(RBOP)is an essential safety-ensuring equipment in underbalanced drilling.The rubber core is a crucial component and sealing unit of the RBOP,whose sealing performance determines the RBOP’s sealing capacity.The rotating blowout preventer’s rubber core is examined in this article,along with its workings and flaws.Based on national standards and patents,a three-dimensional model of the rubber core is created.The Yeoh model,a constitutive model appropriate for rubber core materials,was chosen after study and research.Using experimental data from the uniaxial tensile test of rubber materials,ABAQUS software was used to fit the unknown coefficient of the constitutive model.The contact pressure and deformation between drill pipe and rubber core were investigated and estimated under various well pressures using an ABAQUS software-based three-dimensional mechanical model of the contact.Under various wellhead pressures,the rubber core seal pressure change rule was discovered.The inner cone of the rubber core started to distort as the wellhead pressure progressively increased,and the deformation got worse as the pressure got higher.When the primary sealing surface and the inner cone make contact,stress is concentrated.The contact pressure of the rubber core is examined when the wellhead pressure is zero and the drill pipe joint travels through the interior hole of the rubber core.A theoretical foundation for failure analysis,rubber core design,and rubber core manufacturing is produced by determining the change rule of the contact pressure in each node of the inner cone of the rubber core.