A Study Of Influence On Carbon Dioxide Corrosion Rate By Velocity

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. Service-span of pipeline equipment for oil-gas production and transportation decrease, velocity plays a key role in corrosion. Therefore, studying the mechanism and corrosion rate prediction model of the carbon dioxide provides an practical guiding significance in oilfield production.Based on the similarity theory and simulation of the actual pipe flow environment,this paper designed and manufactured a dynamic corrosion test device,which could simulate the pipe flow whose velocity was less than 3m/s and provide closed type of carbon dioxide dynamic simulation test. The article run static and dynamic corrosion experiments of carbon dioxide on the A3 steel at different temperatures and different conditions of ion concentration, used the simulated oil field produced fluid as the corrosive solution.The experimental results showed that the corrosion rate reached the highest value while the temperature of the corrosive solution is 60℃and velocity is around 2m/s.Corrosion rate increases with increase of velocity less than 2m/s,and velocity has little effect on the corrosion rate when velocity greater than 2m/s.The dynamic corrosion test of carbon dioxide has a 1.13-8.81 times corrosion rate higher than static corrosion coupon test of carbon dioxide.This paper analyses the mechanism about velocity's influence on carbon corrosion rate,studies mechanism and influence factors of corrosion scale and pitting.In the end,the article establishes a uniform corrosion rate prediction model with compiles VB program and the least square method,verifies the results with experimental data.