Study On Corrosion Characteristics And Control Measures Of Gathering Pipe Network In The Old District Of Western Sichuan Gas Field

Currently, there are 718 gathering pipelines (a total of 1329km) and 30transmission pipelines (a total of 630km) in western Sichuan Gas Field, which belongs to Sinopec Southwest Branch Company. Most of the pipes have been built for 10 to 20 years, and the application of 20# steel occupies a very important position in pipeline network.In this paper, a comprehensive survey of the current corrosionsituation and the corrosive environment of gathering pipeline in old westernSichuan gas field has been made. Specifically,the present construction situation, the corrosion situation and anti-corrosion measures has been investigated, and the environment of medium fluid has been analyzed. On the basis ofabove information, the Corrosion of 20# steel in simulated environment characteristic has been researched by experimental study.By the use of single-factor corrosion static corrosion test, uniform design, polarization curves, electrochemical impedance spectroscopy, spectroscopy method of test analysis and SEM analysis, the corrosion situation of 20# steelin western Sichuan gas field has been studied on. The research result shows that the local corrosion of 20# steel corrosion damage more serious than general corrosion, the soil pH value is the most importantfactorof the corrosion of 20# steel. Also, the tests revealsthe trend that low content of Cl" solution acceleratesthe corrosion, while high content of Cl- a solution preventscorrosion.Through simulation test, it shows that the anticorrosive ability of 20# steelis at medium levelin west gas fields soil environment corrosion resistance.According to the results of the experiment, combining with the actual status of the old western Sichuan gas gathering pipeline network, this article proposed the basic measures for gathering pipeline external corrosion control in the old gas field of western Sichuan, including early pipeline design, the choice of pipe material, the selection of pipeline coatings, reinforced pipe repair technical selection and improvement methods of pipeline corrosion detection. The paper has the reference value to the "efficient, economic and safe" operation of the old western Sichuan gas gathering pipeline network.