Abstract:
Objective In view of serious pipe corrosion of gathering and transportation platform in southwest Zhaotong shale gas block, the study of corrosion and prevention of shale gas pipeline was carried out.
Methods By analyzing the corrosion of the elbow, it was determined that the corrosion products mainly were iron carbonate and iron oxide. The promoting effects of carbon dioxide content, carbon dioxide partial pressure, erosive carbon dioxide, dissolved oxygen, flow rate, sand production and bacteria on the corrosion are investigated.
Results It is found that carbon dioxide corrosion promoted by dissolved oxygen is the main factor of pipe corrosion. The higher total carbon dioxide content of the fluid and the higher the partial pressure are, the more serious the corrosion is. The flow rate and sand content of the fluid have a greater promoting effect on the corrosion, while bacteria and chloride ions have no obvious promoting effect on the corrosion.
Conclusions At the same time, two kinds of inhibitor of imidazoline and Mannich base were selected to improve the corrosion inhibition performance. The field application showed that imidazoline inhibitors had good corrosion-inhibition performance, and the rate of corrosion-inhibition could be as high as 95%.
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