Prediction of Residual Service Life of Oil Pipeline Under Non-stationary Oil Flow Taking into Account Steel Degradation

Analytical researches of growth of internal surface cracks in oil pipeline pipe wall under real conditions of operation and determination of its residual service life were carried out. The analysis of the operating conditions of the pipeline was carried out during the research. It is believed that the flow of oil is turbulent with possible hydraulic shocks; produced water is collected at the bottom of the pipe, which causes corrosion in contact with a crack in the pipe wall. An important point in these studies is to consider the corrosion-hydrogen degradation of the pipe material (X60 steel) when calculating its residual life. Such calculations are based on a mathematical model of corrosion crack growth in metallic materials under appropriate loading conditions, in particular time variables (turbulent oil flow with hydraulic shocks), the action of the corrosive environment (groundwater) and the change in the characteristics of X60 steel over time as a result of its degradation. It is shown that the turbulence of the oil flow and the shocks significantly reduce the residual life of the pipeline. The degradation of its material (X60 steel) over time puts the value of this resource in the interval between the values of the residual life of the degraded and not degraded pipe.