University scientists have developed an accurate method for assessing the remaining service life of offshore oil platforms.

Scientists from the Gubkin Russian State University of Oil and Gas (National Research University) have developed a method for determining the remaining service life of welded joints and supporting structures of fixed offshore platforms with accumulated fatigue damage. This development will extend the safe operation of offshore facilities.

"This technology will help reduce the risk of accidents that can lead to loss of life and significant environmental damage," emphasized Ivan Starokon, project manager and head of the Department of Automated Design of Oil and Gas Industry Structures at Gubkin University.

One of the main causes of platform accidents is fatigue failure of metal due to exposure to an aggressive marine environment and corrosion.

"An example of such an accident is the destruction of the Alexander L. Killand platform, which resulted in the deaths of 120 people. Today, production on the shelves of the Caspian, Black, Baltic, Arctic, Sakhalin, and many other regions is carried out using precisely these types of fixed platforms. Many of them have been in operation for over 20-30 years—a period that cannot be considered reliable. This requires special attention to ensuring their safety," noted Ivan Starokon.

Scientists from Gubkin University have for the first time compared three methods for repairing welds at such facilities: conventional crack welding with the installation of crack arrestors, welding in a new section of metal to replace the damaged one, and applying a reinforcing overlay over the crack.

"Until now, there was no theory that could calculate the service life of a repaired joint—its fatigue limit could not be determined analytically. To obtain more accurate data, we built special rigs where we tested the repaired welds until they failed again," explained Ivan Starokon.

Tests demonstrated how many load cycles (such as wave impacts and other loads) the repaired structures could withstand before a new crack appeared, and also identified the maximum allowable load. The fatigue limit for repaired welded joints, depending on the chosen repair technology, ranged from 13 to 15 megapascals.

Research showed that regulatory documentation often underestimated the remaining service life, leading to premature decommissioning of platforms and, consequently, significant costs. On the other hand, there was no accurate prediction of the structural endurance after repair, potentially leading to safety violations.

"If metal fatigue is not detected in time, the consequences can be catastrophic—just recall the major accident at the Deepwater Horizon in the Gulf of Mexico, where dozens of people died and oil spills led to environmental consequences. Our method allows us to accurately assess the actual condition of the metal and understand which repairs will truly extend the life of the platform, rather than simply create the appearance of safety," explained Ivan Starokon.

Scientists hope to integrate this development into the industrial safety system during mandatory platform assessments after 20 years of operation, as required by federal law. This will not only ensure personnel safety but also economically extend the service life of existing platforms without constructing new ones.

The Russian Government has approved a strategy for the development of the mineral resource base through 2035, which identifies the development of the continental shelf as a key priority. The document, developed by the Russian Ministry of Natural Resources, calls for active geological exploration of the Arctic seas, the Caspian Sea, the Black Sea, and the Sakhalin shelf, where significant hydrocarbon reserves are concentrated. With onshore deposits depleting, offshore projects are becoming a strategic reserve for maintaining Russia's energy independence and export potential.

Research and development to improve the operational safety of offshore production platforms and extend their effective service life are consistent with the objectives of this strategy.