Study On The Evaluation Of The Cathodic Protection System Of Sulige Gas FieldGathering Pipeline Network

The total length of gathering and transportation network has been more than 1000 kilometer in Sulige gas field,found by field research,most of the gas pipelines were only a few years in service,but part of the pipelines were not in reasonable state.According to the operation experience of domestic and international pipeline,it could know that the protection of the pipeline was very important in this time,once corrosion had occurred in the early stages,it would have a great impact on the service life of the late pipeline.In this paper,through the investigation and testing of the original cathodic protection system of the gathering and distribution network in Sulige gas field,the operation of the cathodic protection system equipment and the cathodic protection potential of the pipeline were tested and evaluated,it found that the reference potential of potentiostat was not normal in the NO.1 natural gas treating plant,NO.2 and NO.5.It is recommended to allow manufacturers to maintain.At present,the cathodic protection potential of some pipelines were under-protected in the Sulige gas field,and some pipelines were in unprotected state,it would need to increase the cathodic protection equipment and potentiostat in the sixth natural gas treatment plant,Su 14-1 station,Tao 2-4 station and Su 47-1 station,it would protect the unprotected pipeline.Through the indoor simulation experiment,the aging effection of coating on IR was studied,based on the data of the test piece and the soil resistivity and the service life of the pipeline,the relationship between the surface potential and the corrected potential Vs was established,which established the evaluation basis for the cathodic protection of the Sulige gas field,The cathodic protection station and protection of the main line were evaluated in full in Sulige gas field.The results showed that most of the network pipe have been in normal protection at present,for pipelines that were not protected fully,it was recommended to increase the output of the cathodic protection as appropriate,so that the surface protection potential of the pipe network should be adjusted to at least-0.95 V.For pipelines with a service life of more than 10 years,the pipeline should be adjusted to minus-1.0V.The insulation protection layer of cathodic protection pipeline in the three factory area were analyzed by using the pipeline current density and the pipeline potential attenuation coefficient,most of the pipe insulation layer were in a normal state in area,but in Su 6-1 and Tao 2-2 station,part of the pipeline insulation layer had a certain problem,the current leakage was more serious,it would need to strength its cathodic protection.Aimed at the situation and characteristics of oil and gas pipelines in the area,In this paper,the application of sacrificial anode in cathodic protection was studied by numerical simulation technique.It was proved that the soil resistivity and the quality of the anticorrosive insulating layer affected the distribution of the cathodic protection potential of the buried pipeline,the protective effect of sacrificial anode was used in the local area,which provides a more reasonable method and theoretical basis for cathodic protection of Sulige gas field.