The ExxonMobil-operated Hibernia platform is located in the Jeanne d’Arc Basin, approximately 315 km east of St John’s, Newfoundland, and Labrador in Canada. They required two new 60t platform cranes to replace the two existing 45t platform cranes. Conbit was asked to perform the feasibility study to provide an efficient concept for the task. In collaboration with Wood and ExxonMobil, Conbit gathered all the necessary information, explored various engineering ideas and equipment, and presented a feasibility report to shape an effective solution for the project.
Dynamic lifting with a temporary crane
The principle is that before dismantling the existing platform cranes, they will be used to lift the new and temporary crane parts onto the platform. The entire replacement can be performed with the temporary crane working from the deck with no offshore lifting.
Detailed information about the deck loads coming from the selected temporary crane and items on the deck will be provided to match them with the structural feasibility of the platform. The temporary crane was planned to be installed on the pipe deck with drilling operations on hold, allowing the deck to be freed up completely.
Conbit’s solution offers an alternative to using a large crane vessel. The client was committed to evaluating the option to save costs and increase project flexibility.
The feasibility report
Conbit presented the gathered information and analysis of the study. They proposed the temporary crane position, types and loads, laydown areas, deck space and deck loads for/from all lifted items, and the working order of replacement. The report also includes the procedure of lifting items from and to the deck for both the east and west crane exchange. Furthermore, the execution schedule and budget estimate were prepared to align with the presented concept.
Based on this feasibility study and initial structural checks, Conbit is convinced that the proposed solution would efficiently replace the two platform cranes.