Water plants constructed to process brackish and fresh water sources for in-situ thermal oil sands production have noted failures associated with corrosion. The approach to resolve observed problems may depend on the local or upstream operating conditions, and may involve improved monitoring capabilities, additions of chemicals, and/or material selections. The unpredictable occurrences of serious corrosion issues related to the complex water chemistry make it difficult to choose the appropriate preventative and mitigation measures. This is further complicated by the effects of temperature, pressure, and flow turbulence on the equilibrium concentrations of the different species. Considering that the water chemistries are continually changing, it is beneficial to establish operating windows for the different chemical components and determine the effect of operating parameters such as turbulence and temperature. A better understanding of the singular and interactive effects of dissolved ions and gases in the waters is a necessary precursor for an effective integrity management program.
The current paper details selective findings related to corrosion of brackish water systems used for in-situ thermal operations. The effect of pH, bicarbonate and oxygen were studied using model brackish water and the results show that the corrosion rates were significantly impacted by the pH and oxygen levels, while the reduction of the bicarbonate (alkalinity) content of the brackish waters did not sufficiently reduce the overall corrosion kinetics.