The effect of in-service degradation on the deformation behavior of the material of gas mains in soil acid electrolytes has been studied, and it has been shown that depending on the concentration of the corrosive components of the environment, the strain increment can be up to 20-30%. It has been found that in soil acid electrolytes, degraded pipeline steel shows a tendency to sudden strain jumps, which can cause spontaneous depressurization of the pipeline.

Purpose: Determination of regularities of joint action of mechanical stresses, formation water and hydrate formation on corrosion of material of flow pipelines. Design/methodology/approach: According to the analysis of reservoir water of the investigated deposits, it was found that the main corrosive component is soluble chlorides. Proposed for corrosion and corrosion-mechanical tests of 6 model environments. An estimation of the influence of stress concentration, depending on the defects of the inner wall of the pipe, was carried out, and the nominal local stresses in the pipeline was carried. Findings: The basic regularities of influence of stress and hydration formation on corrosion and localization of corrosion processes and on the kinetics of deformation of samples are described. For samples made of steel 20 and 17GS, an increase in the velocity of general and local corrosion for samples sustained in the gas hydrate was observed compared to the control results obtained, the coefficient of influence of the gas hydrate on corrosion was calculated. Research limitations/implications: The obtained results are valid for thermobaric operating conditions of well flow lines. Practical implications: The data obtained in the work on the patterns of corrosion processes and the impact of hydrate formation on them will allow to identify potentially dangerous areas of flow lines and prevent emergencies. Originality/value: Based on the analysis of the geometric dimensions of the defects, the effective stress concentration coefficients are calculated, and it is shown that the stresses in the vicinity of corrosion defects in normal operating modes range from 164 to 545 MPa.

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