CORROSION OF WELDED CARBON STEEL PIPES IN OIL PRODUCTION FIELDS AND ITS MITIGATION

Abstract

In oil production fields, corrosion of welded carbon steel pipes frequently occurs in areas near welds. Corrosion in other areas may take place at a lower frequency and with a lower detrimental effect. In this thesis, a field survey is conducted of eight oil petroleum fields over a period of seven years. Testing of specimens of carbon steel welded joints is carried out under simulated conditions. This study investigates the predominated corrosion damage mechanisms in welded carbon steel pipes. It examines the critical factors triggering corrosion mechanisms and the techniques for corrosion monitoring and mitigation. Flow-induced corrosion and preferential weld corrosion were found to be the most effective mechanisms compared to pitting and microbiologically induced corrosion. Detrimental factors of corrosion mechanisms include flow rates and changes in process parameters of pH, fluid resistivity, and some anion concentrations. The corrosion mitigation was achieved by increasing the dosage of injected corrosion inhibitors.