Water Chemistry for Corrosion Prediction in High Pressure CO_2 Environments

摘要

Transportation of hydrocarbons accompanied by a liquid or supercritical CO_2 phase has recently become a significant concern in the oil and gas industry particularly as related to exploitation of high CO_2 content gas-fields. The issue of internal line corrosion under such condition has a much broader relevance - it is applicable in the field of enhanced oil recovery as well as CO_2 sequestration and transportation. Many different CO_2 corrosion models can predict worst case corrosion rates of mild steel in the CO_2 partial pressure range up to 10 bar, however they grossly overestimate the corrosion rates as the partial pressure gets higher. One important first step in understanding the corrosion mechanisms of mild steel in high CO_2 content environments is to develop methods to predict the corresponding water chemistry. The present study focuses on modeling and model validation of water chemistry in the presence of large amounts of CO_2, with partial pressure varying up to 100 bar and temperature up to 100°C, covering gas, liquid and supercritical phases of CO_2.