Calculated-Experimental Estimation of Residual Pipeline Resource for Long-Term Operation

Production and transportation of oil and petroleum products are currently carried out through welded main pipelines, the operational life of which is largely determined by the processes of deformation aging, re-variable loading cycles, the structure and properties of tubular steels, and their welded joints, as well as the type, size, and nature existing defects. Typically, the destruction of such pipelines is due to internal corrosion of the pipes. With the existing estimation of durability and residual life of pipelines, the principle of summation of damages is used, according to which during the operation of pipelines, damage is accumulated in places with a high concentration of stresses. There is a mathematical expectation, the destruction will occur as soon as the total damage is 100%. In this paper, it is shown that the criterion for estimating the longevity of a pipeline (or residual resource) over the entire period of operation depends mainly on two main factors: the ultimate residual plasticity of the metal of the pipe that was in service and the evaluation of the metal damage in the most problematic zone of the pipe. In this case, the decisive influence on the durability with the remaining unchanged parameters of the pipeline is the appearance of the defect, and its geometric characteristics determined during the diagnostic process. The article provides an example of calculating the durability of a pipeline for pumping gas condensate in the area of the Medvezhye deposit (the Kola Peninsula of the reliability site).