基于有限元的含腐蚀缺陷原油集输管道剩余强度研究

Study on residual strength of crude oil gathering and transportation pipeline containing corrosion defects based on finite element

为研究含腐蚀缺陷原油集输管道的剩余强度,以延长油田集输系统常用的20#管线钢为例,采用ABAQUS建立1/2腐蚀管道有限元模型,研究单个均匀腐蚀缺陷对集输管道剩余强度的影响,分析缺陷位置、缺陷长度、缺陷宽度和缺陷深度的影响规律,并采用Matlab对缺陷长度和缺陷宽度角的模拟结果进行拟合,拟合确定系数R 2均达99.0%以上。结果表明:集输管道的剩余强度受缺陷位置的影响较小;随着缺陷长度的增加先减小后保持不变,随着缺陷宽度的增加先略微增加后保持不变,建立缺陷深度分别为1.5,2.0,2.5 mm的有限元模型,得到缺陷临界长度分别为210,140,130 mm,缺陷宽度角分别为56°,57°,141°;剩余强度受缺陷深度的影响最大,会随着缺陷深度的增加而减小;缺陷深度越大,缺陷长度和缺陷宽度对剩余强度的影响越大。

In order to study the residual strength of crude oil gathering and transportation pipelines containing the corrosion defects,taking the 20#pipeline steel commonly used in the gathering and transportation system of Yanchang oilfield as an example,a finite element model of 1/2 corrosion pipeline was established by using ABAQUS,and the influence of single uniform corrosion defect on the residual strength of gathering and transportation pipeline was studied.The influence laws of defect location,defect length,defect width and defect depth were analyzed,then the fitting on the simulation results of defect length and defect width angle was conducted by using Matlab,and all the fitting determination coefficient R^(2) reached more than 99.0%.The results showed that the residual strength of the gathering and transportation pipeline was less affected by the defect location.With the increase of defect length,it decreased first and then remained unchanged.With the increase of defect width,it slightly increased first and then remained unchanged.The finite element models with the defect depth of 1.5 mm,2.0 mm and 2.5 mm respectively were established,the critical lengths of defect were 210 mm,140 mm and 130 mm,respectively,and the defect width angles were 56°,57°and 141°,respectively.The residual strength was most affected by the defect depth,and it decreased with the increase of defect depth.The greater the defect depth,the greater the influence of defect length and defect width on the residual strength.