Research On Integrity Of Buried Gathering And Transportation Pipeline Based On Artificial Neural Network

Gas field pipelines play a key role in gas transportation in all production stages.The integrity of pipelines is important to ensure safe operation and avoid environmental contamination.The integrity of gas field pipelines is seriously threatened by internal and external corrosion.Cathodic protection is one of the important methods used for protecting gas pipelines from corrosion.Proper design,installation,and maintenance of cathodic protection systems are critical to ensure their effectiveness in preventing corrosion and extending the service life of gas piplines.The research objective is to study the cathodic protection system’s effectiveness;through data published in the literature,gas fields in China were taken as a research case.A comprehensive scientific analysis based on the on-site survey was carried out for 10 main lines,90 branch lines,1A-2A communication line,and 26 protection stations in the gas fields,evaluating the cathodic protection of gas collection and transmission pipelines.To provide a better understanding of the current situation of the cathodic protection system for the gas fields,the effectiveness of these pipelines,calculation of protection range for each station,and detection of pipelines that need maintenance are considered.Accordingly,suggestions are provided based on the analysis.Several factors can affect the performance and effectiveness of cathodic protection systems for gas pipelines,such as soil resistivity,coating integrity,electrical power supply,and others.Through the study of factors of the research case,the external coating defects were relatively low.the resistance of the soil around the gas collection and transmission pipelines is relatively high,which reduces the corrosion rate of the pipelines.In addition,there is an effect of stray currents around the collection and transportation pipeline.By analyzing the current situation of 26 cathodic protection stations in service in the gas field,it can be concluded the following:(1)The layout of cathodic protection stations currently in service is reasonable.Except for the pipelines lacking data,91.5% of the branch lines have been well protected,and the protection rate of the main line has reached 100%.(2)In the pipeline branch lines,the terminal potential is lower than 850 m V.From the perspective of operation and long-term development,protective measures should be taken for these pipelines.(3)The endpoint potential detection results of the 10 trunk lines in the gas field show that the data are all greater than 850 mv,indicating that the pipelines are well protected.However,in some pipeline protection lengths,the actual length exceeds the theoretical effective protection length.This study chose COMSOL Multiphysics 5.6 software.Based on the idea of finite element method,and using the COMSOL software platform,the finite element analysis of cathodic protection for long-distance pipelines is carried out.(1)According to the pipe diameter and other characteristics of all branch lines,the finite element simulation was carried out for 8 types of pipelines,and the potential values of the corresponding test piles were calculated.compared with the actual measured values,the relative errors of the measured values and calculated values were all less than 10%.It shows that this model is reliable.(2)According to the simulation results,the results of this model are in line with the current situation of the potential distribution of the collection pipeline.(3)According to the pipe diameter and other characteristics of all trunk lines in the gas field,finite element simulation is carried out for all trunk lines,and the potential values of corresponding test piles are calculated,and compared with the actual measured values,the relative errors between the measured values and calculated values of trunk lines are basically less than 10 %,indicating that the model is reliable.