Research on Corrosion Behavior of P110SS Tubing in High-Temperature and High-Pressure H2S Environment

The exploitation of China’s oil and gas resources has advanced into the “ten-thousand-meter” ultra-deep realm. Downhole tubulars and well control equipment materials face severe corrosion challenges under the extreme high-temperature, high-pressure, and highly acidic environments prevalent in such formations. However, the corrosion mechanisms and patterns of materials under these harsh conditions remain insufficiently elucidated, necessitating systematic research. This study focuses on the typical casing material P110SS, investigating its corrosion behavior in high-temperature, high-pressure H2S/CO2 environments. The results show that at a partial pressure of H2S of 0.5 MPa, the corrosion rate of P110SS increases with temperature. A significant increase in the corrosion rate and the occurrence of pitting corrosion were observed between 100 °C and 140 °C. The corrosion product transformed from mackinawite to pyrrhotite. At 60 °C, increasing the partial pressure of H2S led to a slight increase in the corrosion rate, while at 160 °C, the corrosion rate slightly decreased. However, temperature changes did not cause any alteration in the corrosion products.