Congo LNG – Creating a New Fast Track Offshore LNG Terminal Re-Utilizing Existing Assets

Abstract Objectives/Scope After Tango FLNG became commercially available, a new Client was found for the floating liquefaction unit at the Marine XII oil and gas field in Congo. To implement a fast-track LNG export solution, a solution needed to be found to moor Tango FLNG offshore Congo. Moreover, an FSU needed to be placed adjacent to Tango FLNG to ensure the terminal had sufficient LNG storage capacity. Tango FLNG, which has a liquefaction capacity of approximately 1 billion cubic meters per annum of gas (BCMA), had to be moored 3 kilometers offshore along with the Excalibur FSU. Excalibur was an existing 138,000 m³ LNG carrier from the Exmar fleet, delivered by Daewoo in 2001. Methods, Procedures, Process The entire upgrading and conversion of both the FSU and FLNG were done in less than 12 months. Several success factors have contributed to the fast delivery time of the complex project whereby engineering, procurement and construction were all done in parallel. Once completed from the conversion yard, both units went to Congo and in about 1 month time the split mooring system installation was completed, and first gas was received. With feed gas available the Exmar teams started to commission the unit and only 2 months later the first LNG cargo was exported from the new LNG terminal. Results, Observations, Conclusions The paper will discuss from a high-level point of view the EPCIC management of the complex conversion project and will explain how all tasks were completed in parallel to achieve a successful and safe project completion within a set timeframe Novel/Additive Information: A novel mooring system was invented by Exmar, acting as EPC and Commissioning contractor for the terminal, to moor both units together in shallow water near shore conditions. The "split mooring" is a combination between a spread mooring system and a side-by-side mooring system. Since the split mooring was a completely new and before non-existent concept it meant that the EXMAR teams had to prove via a technology qualification assessment (TQA) by the classification society Bureau Veritas that it will work and remain intact up to the 100-year storm conditions. Apart from the mooring system and the required mooring upgrades on Tango FLNG and Excalibur, several other systems had to be implemented to ensure both units could act as one terminal: