The Research of Corrosion Behaviour of 13 Cr Pipes in Gas Injection Wells with Oxygen Flooding

Objective: To address the corrosion and protection issues of wellbore pipes using oxygen-containing gas injection, dynamic corrosion experiments were conducted on 13 Cr material under different oxygen-containing conditions to study its corrosion behavior and provide data support and reference for designing wellbore anti-corrosion strategies. Method: Dynamic corrosion experiments of 13 Cr material under different oxygen conditions were conducted by simulating the wellhead, mid-well, and bottom hole conditions (25–135 °C, 25–35 MPa) of a gas injection well in an oilfield in Bohai Sea. Different oxygen containing gases (oxygen content of 5, 10, and 21%) were used for a period of 14 days, and the corrosion rate over time was studied based on the bottom hole conditions (experimental period was 3–30 days). Result: The results of dynamic corrosion experiments show that the corrosion rate of 13 Cr pipes increases with the increase of oxygen content, and the overall corrosion rate remains mild corrosion, which is fully applicable to the working conditions of injection wells. In the actual production process, even if the corrosion intensifies due to the increase in oxygen concentration during long-term injection of oxygen-containing gas, it can be solved by adding corrosion inhibitors. Significance: The research on oxygen-containing flooding corrosion and protection at home and abroad is still in the basic stage. There is no literature report on the prediction method and anti-corrosion chart of oxygen corrosion. This study will have a positive promoting effect on the formation of the theoretical system of oxygen corrosion laws.