Petroleum industry rapid development requires prompt decision-making. The main focus is given to the industrial risks at offshore facilities, since this allows forecasting possible failures and avoiding explosions, fire or hydrocarbon spills. The offshore structures risk mitigation program contains technical, technological and organizational solutions, which allows converting the marine facilities to the recoverable systems and prolong their service life. As of today, Vietsovpetro operates the offshore facilities of fixed and wellhead platform type, the most of which have been built over 25 years ago and running out of their initially designed lifespans. Moreover, due to the long operation, many facilities had undergone changes of initial deck structure and equipment layout and have new unplanned wells. Besides man-induced operational factors it is required to consider the environment impact, which weakens the structures by corrosion and fouling leading to increased load from waves and currents. All these aspects lead to the reduced integrity of supporting frames and emergency stop risks of the platform or even collapsing. To ensure safety during operational and critical conditions, the support frames should undergo the reanalysis.
The article covers the stages of reanalysis for the support frames of the offshore fixed platform jacket. The calculation is made in DNV GL SESAM software complying API standards under operational and critical storm conditions. It is determined the period for removing the fouling from the support frames within the high-wave loads areas in order to reduce the cyclic impact to the structure, dismantling the non-required equipment and structures for off-loading the jackets. In case of need to install the unplanned additional wells at the offshore fixed platforms, authors propose the reduction of the existing tilting moment by decreasing the impact area of waves and currents.
References
1. Le Minh Tuan, Aleksan’yan A.A., Veliev M.M., Safe operation of the offshore oil and gas field facilities at Vietsovpetro JV (In Russ.), Problemy sbora, podgotovki i transporta nefti i nefteproduktov, 2011, no. 2 (84), pp. 116–123.
2. Veliev M.M., Bondarenko V.A., Zung L.V. et al., Sbor, podgotovka i transport produktsii skvazhin shel’fovykh mestorozhdeniy SP “V’etsovpetro” (Collection, preparation and transport of production wells of offshore fields of Vietsovpetro JV), St. Petersburg: Nedra Publ., 2020, 456 p.
3. API RP 2A-WSD. Recommended practice for planning, designing and constructing fixed offshore platforms – Working stress design, 22nd edition, 2014, 310 p.
4. AISC-ASD. Manual of steel construction – Allowable stress design, 9th Edition, 1989.
5. Local and technical conditions for 2007 “Gidrometeorologicheskie usloviya i iskhodnye raschetnye dannye dlya proektirovaniya ob”ektov obustroystva mestorozhdeniy “Belyy Tigr” i “Drakon” (Hydrometeorological conditions and initial design data for the design of the White Tiger and Dragon fields).
