Corrosion And Remaining Life Research Of Crude Gathering Pipeline

During all production process in the oil fields, the corrosion problems of the gathering pipelines always happen with the development of oil production. It is a serious problem which not only threatens security oilfield production but also hinder sustainable resources development. Crude oil gathering pipeline system is a organic series system, in which corrosion in specific pipe section will directly affect the overall safety of the whole function of the system. The entire production may be threatened and the surrounding environment may be polluted. In actual production, in order to restrain the corrosion of buried pipeline caused by external environmental factors, asphalt coating and polyurethane foam insulation coating had been widely used on the pipe for protection. It is necessary to detect the anticorrosion layer of the pipeline and to estimate the remaining life of the pipeline for reasons as ensuring the safe operation of the oil gathering pipelines, increasing the ability to predict the accidents of the detected pipe sections, maximizing the service life of the pipe.This paper analyzed the reason in crude oil gathering pipeline soil corrosion, the main measures of pipeline anticorrosion, and the main techniques in the detection of anticorrosive layer. In this paper, X-ray diffraction method has been used in corrosion products detection of inner pipe surface. The pipeline corrosion mechanism analysis based on it. Using electrochemical method such as AC impedance method and Tafel polarization method, the pipe sample corrosion behavior has been studied and the corrosion rate has been calculated on this. According to relative standards of soil corrosive evaluation, soil samples along the gathering pipelines were evaluated. Based on PCM method, the outer anticorrosive layer of gathering pipeline was tested with DM detector. The quality evaluation was made on the test results. Based on extreme value statistics principle, data of external corrosion pit depth has been analyzed. With the result of the analysis, using localized corrosion progress formula, the remaining service life of the gathering pipeline was estimated.