Research of precipitations in assessing the causes of corrosion at gas facilities

Various methods of corrosion monitoring are used to control the aggressiveness of the operating conditions of oil and gas facilities and ensure their safe and reliable operation. One of them is the analysis of the resulting corrosion products and other sediments and deposits to obtain data on their composition. We present the results of studying sediments when determining the mechanisms and causes of corrosion processes followed by the development of measures aimed at the elimination of the factors promoting the corrosion development. The composition of sediments formed at the facilities of a gas complex was studied. Inorganic compounds and elemental composition were analyzed by X-ray diffraction and scanning electron microscopy. It is revealed that elemental sulfur is present in the composition of sediments, indicating the presence of dangerous sulfur-containing compounds in the system (for example, H 2 S). Using IR spectroscopy and chromate-mass spectrometry, the organic components of sediments formed during preparation of the methanol solution of a corrosion inhibitor were determined. It is shown that the reason for their formation is the presence of oil hydrocarbons in the solution. When analyzing the sediments formed inside the water transport pipe, it was shown that they include iron oxides and hydroxyoxides. At the same time, in places of a through defect on the outer surface of the pipe, corrosion products consisting of Fe(II) or Fe(III) hydroxides with layers of anions and water molecules, the so-called «green rust», are formed. Unstable under operating conditions, such a sediment is unable to protect the steel surface from corrosion. The results obtained can be used in conducting corrosion monitoring at gas facilities to identify corrosion factors affecting the formation of sediments and deposits.