Analysis of Pipeline Corrosion Causes Based on Alignment of Internal and External In-spection Data
After magnetic flux leakage testing,a crude oil pipeline in Changqing Oilfield is excavated for typical external corrosion,and it is found that there is extensive corrosion under the insulation pipe.Based on the comparison of pipeline internal/external detection data,cathodic protection,soil resistivi-ty,and AC/DC stray current interference detection,combined with direct excavation results,the causes of corrosion in crude oil pipelines are studied.The results show that cathodic protection,soil re-sistivity,and AC/DC stray current interference are tested in external detection.When there is no AC/DC interference,there is no corrosion on the pipeline body.After internal detection,the detec-tion signal shows that there are a large number of external corrosion defects in some pipelines.A typical large-area corrosion defect is selected for direct excavation,and AC/DC interference testing is con-ducted on this defect.The test shows no interference,and it is found that there is water seepage in the insulation layer,floating rust in the pipeline body below the insulation layer,aging of epoxy coal tar and peeling off from the pipeline body,and bonding between the corrosion products and the foaming material of the insulation layer.The alignment of internal/external detection data can study the impact of the external environment of pipelines on the safety and corrosion of pipeline bodies,and can further improve the pipeline integrity evaluation system.
crude oil pipelineinternal and external inspectioncorrosionagingpeeling
NETL
NSTL
万方数据
