Primary Research on Corrosion Behavior and Corrosion Chart of L80 - 1 Casing Material in a Representative Oil Field in the Middle East

Abstract

In order to provide the basis of the selection of service casing material in a representative oil field in the middle east. The effects of different CO2 partial pressure, H2S partial pressure, water content, immersion time and other factors on the corrosion behavior of L80 - 1 casing material in a representative oilfield in the Middle East was studied by weight loss test, orthogonal test, SEM and XRD. Results showed that water content was the most important factor affecting the corrosion rate of L80 - 1 steel, followed by CO2 partial pressure, H2S partial pressure and temperature, and Cl- concentration was the least. With the prolonging of the immersion time, the corrosion rate of L80 - 1 steel decreased, and the film became more and more compact and flat. With the increase of CO2 partial pressure, the corrosion rate of L80 - 1 steel showed a trend of increase first and then decreased, reaching the maximum value at 2.00 MPa. With the increase of H2S partial pressure, the corrosion rate of L80 - 1 steel increased continuously. The corrosion of L80 - 1 steel was slight in the early stage of exploitation, but once the water content in the produced liquid exceeded 30%, the corrosion rate increased rapidly, so anti - corrosion measures must be taken in the middle and late stages of exploitation. Based on the basic data of corrosion behavior research, CO2 - H2S corrosion charts of several casing steels were drawn. The corrosion charts showed that the application scope of L80 - 1 steel was limited in typical Middle East oil field corrosion environment, and L80 - 3Cr steel might be a better choice for the long - term safe exploitation of oil field as it could balance the requirements regarding corrosion resistance and cost saving.

Keywords

• corrosion|l80 - 1 well casing|l80 - 3cr steel|corrosion chart|high temperature and high pressure|middle eastt