Flow-Induced Corrosion and Erosion-Corrosion Assessment of Carbon Steel Pipework in Oil and Gas Production

An erosion-corrosion investigation was conducted on Nickel-Molybdenum welds taken from pipework which had been in service in the run-down lines of an Offshore facility. The investigation also reviewed the erosion-corrosion performance of the carbon steel parent metal of the pipework in comparison to the weld material. The programme of experiments assesses the potential of various corrosion inhibitors in controlling the material degradation caused by erosion-corrosion on both the weld materials and parent metals. Experiments were conducted using a submerged impinging jet (SIJ) in CO₂ saturated conditions at a fluid velocity of 7m/s with sand loadings of 0mg/L and 100mg/L. Various corrosion inhibitors were assessed for their ability to control the material degradation. The effect of erosion-corrosion was studied using electrochemical and gravimetric techniques. Erosion-corrosion mechanisms are discussed based upon results obtained from micro-structural studies obtained. The mechanisms adopted by the inhibitors which led to a reduction in material loss are also discussed.