Study On Prediction Model Of The Long-distance Pipeline Corrosion Rate And Its Protection

Along with the developments of industry,the requirement of energy is more then ever before among the modern society.And the oil and natural gas are allimportant source of the energy.So the exploitation of the two type energy is well developed and the technology of exploitation is renovating.The natural gas usually contains CO₂ and sometimes also H₂S.If the two species of gas is in dry condition,they are no corrosive.But if they contain vapor,the water will be formed because the tempreture changed, they will dissolve in the water and the solution will be formed.Under this condition the solution will corrupt the metal.The oil also contains CO₂ and H₂S.Sometimes during the exploitation of the oil using the gas of CO₂ to drive the oil out,as a result concentrationof CO₂ is moe much.During the exploitation of the oil there is a lot of water.And CO₂ and H₂S will dissolve in it and formed the solution.This solution is much more corrosive to the metal.Duration this condition,the pipeline of oil and netural gas is seriously erosion and this made it don't to be used.In order to prevent production from being interrupted,it is necessary to establish a model to predict the rate of this type of corrosion and predict the longevity of the pipelines.Before the destruction of corrosion occurred and the corrosion do harm to the environment,we should avoid it.So in many countries a lot of researcher have investigated the phenomena of corrosion,it contains mechanism of reaction of the corrosion,the type of destruction,the conditions of the corrosion reaction,prediction of corrosion rate and its control. According to the present investigation,there has been established some models to predict the rate of corrosion,and these models areb used under special conditions.Because the conditions of the oil field and the natural gas field are more diverse,these models can't be fit to all these conditions. According to the specific condition of the oil and gas fields in Xinjiang,This paper analyses and simulates the samples of the scene,at the same time considering other researchs'achievement.Through the autoclave weight loss , using the mathematical methods and mathematical software to deal with the data of the experiments result,this paper established models of the prediction of the corrosion rate.They are model of CO₂ corrosion,model of H₂S corrosion and model of H₂S-CO₂ corrosion.The result of the prediction models are well close to the original experimental data.So these models are reasonable and close to the conditions of fact.During the experiment we synthesized some type of CO₂ and H₂S corrosion inhibitors,they are HGY-9A,MY-809A and D,J,L,G. A though the former some are effective,they are not very well. The last two types corrosion inhibitors is high effective and the rate of inhibition is over than 90%.So the last two types are fit.During the experiment we have evaluated effectiveness of the corrosion inhibitors by different methods,such as weight loss,electrochemistry and so on,and compared their proportion of inhibition.The result of the experiments show that these two inhibitors are two types of compound corrosion inhibitor,because they all can control the cathodal processes and the processes.They not only relieve the reaction of anodic but also the reaction of cathodal,so they can reduce the rate of corrosion.