CO2 Corrosion Prediction Along the Length of a Flow Line

Previously the development and implementation of a new mechanistic model for oil and gas production environments was described. This initial development was a single point model that predicted the CO₂ corrosion rate for a given set of conditions. The model has subsequently been further developed to simulate the change in water chemistry and associated corrosion rate along the length of a flow line.

As a volume of water moves along the flow line the water chemistry is modified as a result of the flux of iron ions from the corroding pipe wall surface. The associated change in pH from the addition of Fe²⁺ further influences the CO₂ equilibrium. These two effects, varying pH and CO₂ equilibrium, combined in‑turn to affect the predicted corrosion rate. The model simulates the changing water chemistry and corrosion rate by repeatedly recalculating the mechanistic corrosion rate model for small increments of time.

The water chemistry and corrosion rate profiles for prototypical flow line conditions are presented and discussed.