Carbon Dioxide Corrosion Research Of Tube And Casing

With wide application of carbon dioxide injection technology to improve oil recovery and the produced liquid of some oil-gas field contains carbon dioxide, carbon dioxide corrosion become a main problem of oil-gas production. Mechanical properties and service-span of Pipeline equipment for oil-gas production and transportation decrease, especial localized corroded equipment are more likely to be damaged. So, it is very important to research the mechanism of carbon dioxide corrosion, the corrosion rate prediction model and analyze corrosion failure of the equipment.This thesis analyzes carbon dioxide corrosion using corrosion electrochemistry method and divide corrosion process into three steps, state that transmission process in diffusion layer control the whole general corrosion, deduct general corrosion rate prediction model, analyze the main factors which influence carbon dioxide corrosion; Corrosion product film is associate with corrosion process, after summing up research results of corrosion produce film home and abroad, analyze the corrosion product film forming process; The damage of corrosion product film induce localized corrosion and different localized corrosion style has different drive mechanism; Pitting corrosion can be considered to be general corrosion in low pH condition, flow induced corrosion and mesa type corrosion are controlled by the rate of electrode reaction; Deduct a localized corrosion rate prediction model which is useful for oil-gas field; Localized corroded tube are fatigue failure under alternating loads; Corroded casing damage when stress concentration excel yield limit at corrosion pit under external pressure or external and internal pressure.