Analytical modeling of pipeline failure in multiphase flow due to corrosion in Niger Delta Region

Abstract

Pipeline could be said to be the safest and the most economical means of transportation of hydrocarbon fluids. Pipelines carrying oil and gas may suffer from internal corrosion when water is present. The corrosivity varies due to several factors such as; temperature, total pressure, CO₂ and H₂S content in the gas, pH of the water, flow conditions, inhibiting chemicals etc. Corrosion, when not properly dealt with could lead to pipeline integrity issues which will be very uneconomical for the operator company. This research focuses on the development of a model that can predict pipeline failure due to corrosion in multiphase flows. The role that velocity, density, water cut and other parameters play in predicting corrosion is critically analyzed with Norsok Model. The result shows that velocity plays a key role in corrosion prediction.Increasing oil velocity from 0.1 to 1.25 m/s leads to an increase of corrosion rate from 1.67 to 5.58 mm/yr. This is because at the selected pH of 4, the corrosion rate is very sensitive to mass transfer and turbulent mixing which are in turn enhanced at higher flow rates.