Material Selection and Evaluation on Internal Coating of Associated Gas Pipeline in H₂S-CO₂-O₂ Coexistence System in Tahe Oilfield

Abstract

 To study the corrosion behavior of three commonly used steels in associated gas pipelines in the three-gas coexistence system of H2S-CO2-O2 can provide guidance for the corrosion prevention and control of associated gas pipelines in Tahe oilfield.Based on the typical corrosion working conditions in Tahe oilfield and taking 20 steel，L245NS steel and 3Cr steel as the research objects，the corrosion rates and corrosion products of the three steels under typical working conditions in H2S - CO2- O2 coexistence system were studied through high -temperature and high-pressure reactor experiment.Results showed that the corrosion rate of 20＃ steel was the highest，followed by L245NS steel，and the corrosion rate of 3Cr steel was the lowest.The corrosion products of the three pipes were mainly Fe，FeS，FeCO3 and Fe2O3.The corrosion resistance behaviors of four typical internal anti-corrosion coatings in Tahe oilfield were studied through an adhesion test and the weight gain method that involved the measuring of the weight gain before and after corrosion，and the results indicated that coating 2 possessed the optimal corrosion resistance and adhesion.Considering the cost performance，“L245NS+coating 2”was finally selected as the anti-corrosion measure for the associated gas pipelines in Tahe Oilfield.

Keywords

• h₂s-co₂-o_2 coexistence system|associated gas pipeline|pipeline material selection|internal coating evaluation