Internal corrosion direct assessment on the evaluated pipeline section in West China Products Pipeline

In this paper, the internal corrosion of evaluated pipeline sections in West China Products Pipeline was evaluated directly by means of the Liquid Petroleum-Internal Corrosion Direct Assessment method (LP-ICDA), which is divided into four steps, i.e., pre-assessment, indirect inspection, detailed examination and post-assessment. In the pre-assessment step, the data related with the internal corrosion direct assessment of the pipeline section is collected and ordered. In the step of indirect inspection, the multiphase flow model is established and then used to predict the distribution of internal corrosion risk in the period of normal transportation and in the period of shutdown, respectively. Furthermore, the effect of water facies in the early stage of operation is taken into consideration, and the positions of internal corrosion risk in this section are analyzed comprehensively. In the third step, the internal corrosion of this pipeline section is confirmed by means of detailed excavation examination. And in the post-evaluation step, re-assessment time interval of this pipeline section is analyzed. It is shown that this pipeline section suffers internal corrosion, but the pipeline strength is not affected significantly, so it can be still operated under the allowable safety pressure.