Cailiao Baohu (Feb 2022)
Study on Corrosion Performance and Optimization of CO2-Driven Injection Oil Well Tube
Abstract
Different oil well tubes have different influences on CO2 corrosion.In order to optimize the materials with the best corrosion resistance to CO2, it is necessary to explore the corrosion of materials of conventional oil well tubes under different conditions.Therefore, taking the production well of CO2 composite flooding injection in Block nine six of Karamay oilfield as the research object, and simulating the actual service condition of oil well pipes, the corrosion weight loss experiments on N80, 3Cr, tungsten-plated heat insulation tube and P110 oil tube materials were carried out.The Potentiodynamic polarization curve and electrochemical impedance spectroscopy(EIS)were measured by three electrode system, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD)were used to observe the microstructure of corrosion products.Results showed that the corrosion rate of the four kinds of materials increased first and then decreased with the increase of temperature.With the increase of pressure, the corrosion rate of the four kinds of casing steels increased.The corrosion rate of tungsten-plated heat insulation tube and 3Cr was obviously lower than that of N80 and P110.According to the corrosion morphology, the four kinds of casing steels were corroded in varying degrees.The serious corrosion occurred on the surface of N80 and P110 whereas slight corrosion occurred on the surface of the tungsten-plated heat insulation tube and the 3Cr.Therefore, the corrosion law of four oil well tubes in CO2-driven environment was obtained, the suggestions on the design and selection of oil well tubes in CO2-driven environment were proposed to select the materials with the best corrosion resistance to CO2 optimally.
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