On-site corrosion assessment of bimetal composite pipe used in high sour gas fields

Due to the severe corrosion environment, materials like bimetal composite pipes have become the research hot topic in the exploitation of high sour gas fields. The research of bimetal composite pipes mainly focuses on lab experiments, and the wide application has been limited due to the lack of on-site application cases. In order to assess the possibility of bimetal composite pipes applying to the surface pipelines in high sour gas fields, field corrosion behavior evaluation was carried out, and then the evaluation method has formed by using online corrosion test device in Tiandong 5-1 high sulfur gas pilot Test base. The electrochemical corrosion and sulfur corrosion cracking experiments of X52/825 metallurgical composite pipe and L245/825 mechanical composite pipe have been conducted. Field test results indicate that the corrosion resistant layer and weld of X52/825 and L245/825 have good environmental cracking resistance and good electrochemical corrosion resistance. The corrosion evaluation method of bimetal composite pipe has laid a foundation for the field stress corrosion evaluation of composites in the future.