Corrosion Analysis of Shale Gas Downhole Pipes Under Synergistic Action of Multiple Factors
The downhole pipes of a shale gas in southwestern China experience varying degrees of corrosion,posing signifi-cant safety hazards.To clarify the types and mechanisms of corrosion,downhole pipes corrosion analysis research was conducted.The research methods mainly included macro observation,micro observation and composition analysis,fluid dynamics simula-tion.The results indicate that corrosion under the multi factor synergistic effect of erosion-CO2-SRB(sulfate-reducing bacteria)is the main type of corrosion for pipelines under shale gas wells.The growth and enrichment of SRB in the early stage of operation cause local corrosion.After adding fungicides,SRB corrosion stops,and CO2 corrosion continues to develop in the already formed local corrosion location.The flushing effect of fluids such as liquid sand and gas sand promotes the occurrence and deve-lopment of related corrosion.