Corrosion Behavior of 110SS Tubing Steel in Highly Acidic Gas Reservoir Environment

110SS steel is widely used in gas reservoir tubing materials in acidic environments owing to its excellent corrosion resistance and strength.In order to deeply understand its corrosion behavior in high acid gas reservoir environment， the 110 SS tubing coupon was placed in a high temperature and high pressure reactor for carrying out CO2/H2S environment simulation corrosion experiments.The morphology， corrosion rate， product phase，element contents and electrochemical behavior of the corrosion products were studied by means of scanning electron microscope (SEM)， X-ray diffractometer (XRD)， energy dispersive spectrometer (EDS) and electrochemical measurement.Results showed that during the corrosion time of 72～168 h， the corrosion rate of 110SS tubing followed a power function variation pattern and decreased with the prolongation of corrosion time.At 72 h， yellow brown point corrosion products appeared on the surface of the sample.At 120 h， large areas of yellow brown corrosion products peeled off， mainly newly appearing gray corrosion products.At 168 h， uniformly distributed blue corrosion products appeared.Moreover， the corrosion products of 110SS steel mainly include S， FeS1-x， Fe1-xS， FeS， Fe2O3， Fe3O4， FeCl3， FeCO3，etc.， and the self-corrosion current density increased with the prolongation of corrosion time.In general， the results are helpful to better understand the corrosion behavior of 110SS tubing in highly acidic gas reservoir environment.