Comparing and Interpreting Results of Processing In-Line Inspection Data for Corrosive Gas Transportation Conditions

Abstarct

—Many gas and gas condensate fields (Bovanenkovskoe, Urengoiskoe, Kirinskoe, etc.) are distinguished by the presence of corrosive carbon dioxide in the extracted products, which, in the presence of moisture, leads to the formation of local corrosion damage (pits and their accumulations). One of the methods for monitoring the corrosion state of pipelines is in-line inspection (ILI), carried out by the magnetic flux leakage method. ILI is especially relevant for underground and underwater pipelines when the use of other methods of corrosion monitoring is limited or costly. Under conditions of gas production, unlike oil production, corrosion can take place both along the lower part of the pipe (6‑hour corrosion) and during condensation of moisture on the upper part of the pipe (12-hour corrosion). An important process is the correct planning of the ILI, the subsequent processing and interpretation of the obtained data set, which should be carried out taking into account the peculiarities of the development of carbon dioxide corrosion in the gas pipeline and in a comparative analysis with other corrosion monitoring data. When interpreting the ILI data, one should take into account the mechanisms of corrosion development, operating conditions (path profile, etc.), and corrosion monitoring data obtained by other testing methods (simulation tests, results obtained at other, adjacent sections of pipelines, etc.). Correct and useful information according to ILI data will ensure reliable protection of gas pipelines and planning of measures to protect them against internal corrosion.