T.I. Lapteva, Cand. Sci. (Eng.), Deputy Head, T_Lapteva@vniigaz.gazprom.ru M.N. Mansurov, Dr. Sci. (Eng.), Prof., Head of Department M.V. Shabarchina, Research Associate S.D. Kim, Cand. Sci. (Eng.), Senior Research Assistant L.A. Kopaeva, Research Associate ОOO Gazprom VNIIGAS, Razvilka, Russia
The issues are considered concerning the assessment of reliability of the offshore pipelines by creation of the theoretical approach with the development of the relevant methodical base, which will allow to assess the design and operational reliability of the offshore pipelines in the severe engineering-geological conditions of the continental shelf. Neglect of such factors as subaqueous permafrost rocks in the transit area, increase in density of the sea water as a result the dredging works, unevenness along the route of the offshore pipeline can lead to serious consequences up to its depressurization. The results are given related to the estimate of the conditions of the offshore pipeline steady state position with the indication of dependence of the offshore pipeline steady state position against surfacing on the type of bottom soil. The results are shown concerning the theoretical researches of substantiation of strength and stability of the offshore pipelines at change of bottom soil properties, which consist of friable subaqueous permafrost rocks at the sites of landfall of the continental shelf zone. Frost penetration and thawing of subaqueous permafrost soil results in emergence of additional longitudinal sresses owing to what there is a change of the planned-high-altitude position of the offshore pipeline. The issues are highlighted concerning possible economic damage as a result of depressurization of the offshore pipeline depending on the pumped product against the background of essential uncertainty in the basic data caused by the probable nature of natural processes and the phenomena.
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