Coral South FLNG Technology from Screening to Real Application
Authors: Rossi Francesco 
Published: November 2017

The present article collects the main activities carried out by Eni on FLNG in the past years. As such, it reports Eni’s view of the FLNG technology and it constitutes a subjective assessment and evaluation of the involved technologies and the associated risks. The same evaluation and assessment may lead to very different results when based on a different risk perception, which is proper of each Oil Company.

At time of writing, Coral South FLNG Project has obtained Final Investment Decisions from all the Project Partners and the FLNF EPC contract has been awarded, with consequent commencement of detailed engineering and construction activities.

The paper will present the activities carried out in Eni about FLNG in the past years, then used to validate and enable the development of Coral South FLNG Project. In particular, it will briefly present the main technological features studied and selected by eni for the Coral South Project. It will summarise the main studies carried out and the main advantages and disadvantages considered by Eni when selecting the technologies adopted in the Coral South FLNG Project.

As a conclusion, the paper will summarise the main technological configuration of Coral South FLNG facilities based on the validation activities carried out.

Coral South FLNG Project finds its basis in an extensive preparation activities, as FLNG technology has been studied in Eni since 2008, when some stranded oil&gas fields required valorisation with offshore LNG technology. A series of activities and project-based pre-feasibility and feasibility studies have been carried out in the following four years, preparing the ground and unlocking Coral South Project in Mozambique.

The main technologies studied and screened are: –Liquefaction process technology;–Refrigerant make-up production technology selection;–LNG offloading system configuration;–Mechanical drivers for liquefaction compressors and generators;–Heating medium system;–Containment system including sloshing issues;–Mooring system;

For each of these systems, a rigorous and common technology validation approach has been adopted, consisting in a screening of different technical alternatives with a qualitative analysis. When necessary a quantitative evaluation has been carried out, including a detailed engineering assessment, scale tests and a cost and risk comparison.

The final selection has been made taking into account safety, costs and operability. For each technology, a preferred one has been selected firstly as Eni Corporate and then checked and validated for the specific Coral South FLNG Project application.

As result of the extensive application of the technology validation procedure, the originally selected technologies for the generic Eni FLNG have all been confirmed for the Coral South FLNG Project even if in some cases scale tests have been required to further assess the identified criticalities.

When it comes to FLNG application, even the most common and widely adopted technology can be considered as a novelty as there are no previous floating and/or LNG application for it.

Eni approach to this novelty-in-complexity environment is based on an internal ad-hoc developed technology validation procedure which has been demonstrated to be very effective even when applied a real demanding Project like Coral South FLNG.