Oil And Gas Pipeline Slug Flow In The Corrosion Mechanism And Internal Anti-corrosion Technology

From oil well head to assembling gathering station, there is often one or several of oil ,gas and water phases in the mediums transported by the pipelines ,in which corrosive gases such as oxygen, carbon dioxide and sulfureted hydrogen may be dissolved. At the lower reaches of the pipeline flow, slug flow that is extremely turbulent may come into being, which results in severe internal-corrosion of the pipe .Therefore ,it will contribute greatly to the study of oil and gas transportation pipeline corrosion and anti-corrosion techniques to study the mechanisms and characteristics of slug flow corrosion .According to a great deal of investigations and researches of the related literatures, and based on real conditions of internal corrosion of the gathering and transportation pipelines, the mechanisms of several type of corrosion related to slug flow corrosion of oil and gas pipelines are analyzed.Mean influencing facters about slug flow corrosion of oil and gas pipelines are discussed;the way to calculate parameters such as Froude Number ,Wall Shear Stress,Oil Faction, Water Faction and Slug Local Pressure Drop in the fluids is given.Mutiphase flow loop system is introduced to study slug flow corrosion,based on the experiment data , the integrated effects of Froude Number, Wall Shear Stress, Oil Faction, Water Faction on multiphase corrosion are studied using MATLAB 6.0 software .Besides ,the metal corrosion mechanism under slug flow regime is also studied and conclusions are drawn.EIS coating inspecting technique is used to study coating performance and coating abation process.The equivalent circuit model for metal/coating/fluids system is established and improved'according to the corrosion characteristics of the system.The method to treat with data got from EIS measurement is optimized and realized by VB computer programme.The direction for epoxy-bakelite anti-corrosion dope is bettered , autoclave corrosion test, adhesive ability test and wearing capacity test are carried out to evaluate the coating performance ,combined with foregoing study, internal corrosion -inhibiting coating technique of oil and gas pipelines is further discussed.According to the working condition ,with the development of anti-corrosive materials and anti-corrosive techniques, two new anti-corrosive techniques, pipe lined with glass fibre reinforces plastics and spray-enameled pipe, are brought forward on the base of traditional techniques. Through laboratory test, the spray-enameled pipe is proved to get excellent anti-corrosive effect and have a good potential for exploitation and application in the furture.