气体快速减压橡胶失效计算模型建立及分析  

The Establishment of Computational Model and Analysis of Elastomer Failure Induced by Rapid Gas Decompression

作　　者：陈明战 王素玲[1] 姜民政[1] 李金波[1] Chen Mingzhan;Wang Suling;Jiang Minzheng;Li Jinbo(Machinery Science and Engineering College,Northeast Petroleum University;Daqing Oilfield Production Technology Institute;Heilongjiang Province Key Laboratory of Oil and Gas Reservoir Stimulation)

机构地区：[1]东北石油大学机械科学与工程学院 [2]大庆油田采油工程研究院 [3]黑龙江省油气藏增产增注重点实验室

出　　处：《石油机械》2020年第10期142-148,共7页China Petroleum Machinery

摘　　要：当环境气体快速减压时,溶解于橡胶内部的气体无法快速析出而膨胀,使橡胶鼓包甚至破裂,导致密封失效。针对该问题,国内缺乏相关分析方法和模型。为此,提出了一种基于原始空穴缺陷的空心球物理模型,在考虑空心球空腔内气体膨胀导致空心球机械变形的基础上,耦合计算由橡胶基体溶解气体扩散导致的空心球空腔气体压力变化,从而计算得到空心球内壁应变随时间的变化值,并判断其是否达到破裂界限。基于该模型,利用Abaqus建模+Python编程,针对井下封隔器在用NBR材质O形圈,开展了不同压力、泄压速度及缺陷位置等因素对最大名义应变的影响分析。分析结果表明,随着压力、泄压速度及缺陷深度的增加,应变增大,快速减压时失效更易发生,这与室内试验结果相一致。该物理模型及有限元分析模型的建立为高压、高含气工况橡胶密封件的优选和安全性评估提供了有效手段。When the ambient is rapidly decompressed,the gas dissolved in the rubber cannot be released quickly and expand,causing the rubber to bulge or even rupture,resulting in seal failure.There is a lack of relevant analysis methods and models in China in response to this problem.Therefore,a physical model of hollow sphere based on the original cavity defect is proposed.Taking into account the mechanical deformation of the hollow sphere caused by gas expansion in the hollow sphere cavity,the hollow sphere cavity pressure change caused by the diffusion of dissolved gas in the rubber matrix is calculated.The change of the inner wall strain of the hollow sphere with time is then attained,and is used to judge whether it reaches the rupture limit.Based on this model,using Abaqus modeling+Python programming,for downhole packers NBR O-rings,the influences of factors such as pressure,pressure relief speeds and defect locations on the maximum nominal strain are analyzed・The results show that with the increase of pressure,pressure relief speed and defect depth,the strain increases,and failure is more likely to occur during rapid decompression,which is consistent with the results of laboratory tests.The establishment of the physical model and the finite element analysis model provides an effective means for the selection and safety assessment of rubber seals under high pressure and high gas content.

关 键 词：橡胶 气体快速减压 机械变形 气体扩散 耦合 O形圈 ABAQUS 

分 类 号：TE934[石油与天然气工程—石油机械设备]