Combined efforts on TOTAL’s CLOV FPSO

MARIN carried out model tests, real-time simulations and a full-scale monitoring campaign considering different operational

and design aspects of the CLOV FPSO, installed off Angola. Dimitri van Heel, Janou Hennig & Pieter Aalberts,


OTAL operates the Block 17 oil field, which is located approxi- mately 80 miles off the coast of

Angola. CLOV is the fourth FPSO installed in this area and like the other FPSOs, it is spread moored to the seabed. An offshore offloading buoy (SPM) is installed in the same field.

Model tests Seakeeping, towing stability and mooring tests, tug optimisation and hull integrity have all been examined over the last three years. In 2011, MARIN carried out model tests on the CLOV FPSO on behalf of DSME, examining seakeeping, towing stability and mooring. Apart from the wide range of model tests and para- meter variations, some challenges were encountered in realising asymmetrical weight distributions at relatively low pitch- roll coupled moments of inertia. While the model dimensions and scale could be called standard, a slight change in the weight distribution could lead to a signifi- cant change in the FPSO model’s motion behaviour; this order of magnitude corre- sponds to the shift of a small ballasting weight by a centimetre. DSME and MARIN were able to quantify the effect on motion RAOs and the MARIN project team made

20 report

sure that the weight calibration was to the point by using very accurate measurement and calibration methods.

Tug optimisation study During the start-up period drill ships may be operating in the vicinity of the FPSO and their pres- ence constitutes a possible risk to offloading operations at the FPSO or SPM. In a study

executed by MSCN, simulator runs were conducted to determine the number of tugs needed for operations at CLOV. The simula- tions focused on emergency situations in adverse weather conditions (strong currents, squalls) and looked at the tug assistance required to resolve the situations and keep the export tanker clear from any objects in the area.

CLOV FPSO model tests


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