Study On Corrosion Mechanism And Algorithm Of Coastal Pipeline By Coastal Effect And Tide Induction

Earth surface magnetic field intensity change because of the influence of a geomagnetic storm,which leads buried oil and gas pipeline to produce geomagnetically induced current GIC and the pipeline surface potential PSP.China’s oil and gas pipelines throughout the country,through a variety of different geographical location.It was found that the GIC-PSP monitored by coastal pipelines during the occurrence of magnetic storms was significantly higher than that in inland areas.Meanwhile,during the tide,the PSP monitored by the coastal pipeline has a "bimodal-double valley" curve.PSP as an standard for pipeline corrosion,related to the safety of oil and gas transmission.Therefore,the study on coastal pipeline corrosion mechanism has very important significance.Firstly,this paper study the affecting factors on oil and gas pipeline GIC,and analyzes the DSTL model of oil and gas pipeline.On this basis,we proposed a closer buried oil and gas pipelines circuit model,that is,considering the buried pipeline circuit model of the earth resistance.Secondly,taking the coastal pipeline of Rizhao station in Shandong as an example,this paper discusses the phenomenon and mechanism of GIC coastal effect of oil and gas pipeline,and uses the thin plate theory to establish the two-dimensional coastal model.Based on the Maxwell equations and the original data of the geomagnetic station,the electric field intensity of pipeline in Rizhao,Shandong is calculated.According to the pipeline equivalent circuit model,the calculated GIC-PSP of the pipeline is compared with the collected data,and tendency is alike.Finally,the mechanism of tidal induction is discussed,and the tidal induction theory model is established,and the influence of tidal induction on coastal geoelectric field and oil and gas pipeline is analyzed.The influence of tide induction on the coastal pipeline is verified by comparing the data of the measured pipeline PSP with the tide table monitoring data provided by the China Maritime Service Network.