Recuperation of Oil Trapped in Ship-Wrecks: The DIFIS Concept Jean-François Drogou Ifremer

1. Recuperation of Oil Trapped in Ship-Wrecks: The DIFIS Concept Jean-François Drogou Ifremer SAFER SEAS 2007 - BREST 9-12 october 2007

2. Issue • Maritime disasters leading to major environmental pollution happen almost regularly • AMOCO-CADIZ in 1978, TANIO in 1980, AEGEAN SEA in 1992, ERIKA in 1999, PRESTIGE in 2002 • Existing wrecks all over the world with smaller or bigger quantities of hydrocarbons trapped in their tanks constitute a more or less serious threat at shorter or longer term SAFER SEAS 2007 - BREST 9-12 october 2007

3. Need • The REPSOL YPF solution, designed and implemented under emergency conditions for the particular PRESTIGE case, constitutes the state of the art in ROV based interventions at great depths. • The PRESTIGE case has put in evidence, among other things, the lack of tools, systems and methodologies for the prompt intervention on the ship wrecks in order to confine the pollution and, successively, eliminate the source of the pollution threat. • This is exactly the aim of DIFIS project: a method of wide applicability for the prompt intervention on ship wrecks. SAFER SEAS 2007 - BREST 9-12 october 2007

4. Objectives • Stop the pollution Rapid deployment • Eliminate pollution threat Permanent solution At very short term contain / seal any leakages Successively, at a longer term, remove the pollutant from the wreck SAFER SEAS 2007 - BREST 9-12 october 2007

5. Requirements • General: adaptable / applicable in most possible cases • Of rapid deployment / Implementation so that to contain any leaking as promptly as possible • No risk for the structural stability of the wreck • Implemented in phases allowing, with the same system / procedure, both the prompt containment of the leaks and the subsequent removal of the remaining hydrocarbons • As simple and economical as possible SAFER SEAS 2007 - BREST 9-12 october 2007

6. DIFISDouble Inverted Funnel for Intervention on Ship wrecks • The scope of this project is the study, design (including costing, planning, deployment procedures etc) of an EU reference method for the prompt and cost-effective intervention and remediation of tanker wrecks dealing with eventual leaks and recuperating the fuel trapped in their tanks even at considerable depths. • The proposed method will be of general applicability as long as the trapped pollutant does not dissolve and is of lower density than sea water SAFER SEAS 2007 - BREST 9-12 october 2007

7. The DIFIS consortium SAFER SEAS 2007 - BREST 9-12 october 2007

8. DIFIS concept & main components • -Buffer Bell • -Riser Tube stiffening lines • Riser tube • Dome Housing Unit • Dome • Anchoring System Designed by CYBERNETYX SAFER SEAS 2007 - BREST 9-12 october 2007

9. Conceptconceptual study initiated in the frame of ROBMAR network Buffer Bell Dome and Riser tube SAFER SEAS 2007 - BREST 9-12 october 2007

10. Main anticipated issues • Hydrodynamics & structural • Deployment (surface & bottom) • Anchoring • Operations & planning • Costs– regulations IPR SAFER SEAS 2007 - BREST 9-12 october 2007

11. Reference scenarios (1) • A deep waterreference scenario based on the environmental conditions of the PRESTIGE accident: wreck lying at 4,000 m deep, slightly inclined seabed, low temperature, no sea current at sea-bed; strong currents near the surface and adverse sea conditions • A shallow waterreference scenario based on the fact that a DIFIS system would be feasible in terms of design from around 400 m SAFER SEAS 2007 - BREST 9-12 october 2007

12. Reference scenarios (2) • The “PRESTIGE grade” heavy fuel oil is the reference cargo in both scenarios. Moreover, in order to accurately define a range of oils, heaviest and lightest cases of oil cargo are included, to allow for a definition of multiple cargo scenarios. • The wreck of half of a standard double hull ULCCwas opted as the reference target. • Deployment time(as soon as possible) and safety of deployment operations is one of the key design criteria. SAFER SEAS 2007 - BREST 9-12 october 2007

13. Preliminary design • Early design and DIFIS system behaviour • Main elements evolutions • Load calculations • Preliminary Deployment • DIFIS Internal flow analysis • Scaled Model Test SAFER SEAS 2007 - BREST 9-12 october 2007

14. DIFIS system behaviour(4000m) • Pre-tension 1000 ton • Horizontal displacement, 306 m • Vertical displacement – 13.6 m Datas from SENER SAFER SEAS 2007 - BREST 9-12 october 2007

15. System behaviour (400m) • Pre-tension 1000 ton • Horizontal displacement, 4.7 m • Vertical displacement - 0.1 m Datas from SENER SAFER SEAS 2007 - BREST 9-12 october 2007

16. Flow analysis • Flow calculations (Sirehna) SAFER SEAS 2007 - BREST 9-12 october 2007

17. Main elements evolution Buffer bell Diam:14m L:20m Rigid rings,dyneema lines Riser Tube PE-pipe diam.2m 6 mooring lines Steel rings every 50 m Dome Geo-textile-Diam 100 & 200m 12 mooring lines diam 98 mm SENER SAFER SEAS 2007 - BREST 9-12 october 2007

18. 2 m DIFIS internal flow analysis Sirehna SAFER SEAS 2007 - BREST 9-12 october 2007

19. Preliminary principle of deployment • Safe and rapid deployment is the main challenge, and Bulkiness, sizes, and complexity rise as depth of operation increases. • Phase 1: deployment of the mooring anchorage dead weights • Phase 2: Surface deployment of the dome and dome housing • Phase 3: Lowering the Riser tubes along the guidelines • Phase 4: Surface deployment of the buffer bell. • Phase 5: Connecting buffer bell to tensionning lines • Phase 6: Ballasting the Buffer bell • Phase 7: Clamping the buffer bell onto the guidelines • Phase 8: Anchoring the dome using mooring lines • Phase 9: Tightening of the Mooring lines • Phase 10: Freeing the lifting bags for anchoring tensioning • Phase 11: Deploying the dome • Phase 12 : End of deployment and complete survey. SAFER SEAS 2007 - BREST 9-12 october 2007

20. Scaled model test Scale 1:60 Marin Offshore Bassin SAFER SEAS 2007 - BREST 9-12 october 2007

21. DIFIS life cycle SAFER SEAS 2007 - BREST 9-12 october 2007

22. Readiness • It includes all the activities prior to an eventual accident (or the manifestation of a need for a specific DIFIS intervention). • It includes all the activities related to the readiness for intervention. The prime requirement during this phase is preparedness to intervene, within the DIFIS operational envelope, in a) time as short as possible, while (b) tying-down the less capital and human resources as possible. • Activities like design, costing, deployment and tender procedures, eventual pre-fabrication and storage of components, integration of the system in emergency plans and contingency procedures and training of the personnel are included. SAFER SEAS 2007 - BREST 9-12 october 2007

23. Deployment • All the pre-intervention activities after an accident has taken place (or a specific DIFIS intervention need has been manifested) till the beginning of the recuperation phase. 6 broad classes of deployment operations : • 1. Planning and managing the whole project of the specific intervention • 2. On-site survey of the wreck, the sea-bottom and the other local environmental conditions (i.e. sea current profiles, waves etc) • 3. Engineering and implementing the case specific aspects of the intervention • 4. On-site surface deployment: vessel positioning, deployment, assembly of submerged platform (SUP), ROV installation • 5. On-site underwater deployment: anchoring, deployment, positioning, assembly of riser tube and stiffening lines, dome unfolding, buffer bell • 6. Support operations SAFER SEAS 2007 - BREST 9-12 october 2007

24. Intervention • It covers the period after the deployment of the system, where the wreck is covered and all the trapped pollutants are channeled to the Buffer Bell. • The most important operation during this phase is the periodic recuperation of the pollutant from the Buffer Bell, most likely by means of a small, suitably equipped shuttle tanker. • Another important class of operations performed during the intervention phase has to do with the monitoring activities (of the structure and wreck) and, eventually, maintenance of the DIFIS structure. SAFER SEAS 2007 - BREST 9-12 october 2007

25. Post- intervention • It covers the period after the end of the operation phase, when the pollution threat can be considered eliminated. It deals mainly with the recuperation of the system, the evaluation of the intervention as well as eventual feedback, changes and upgrading of the system and / or procedures. • Processing of recuperated pollutant is also a task that needs to be performed in this phase, but remains outside the scope of the DIFIS project. Processing of pollutant oil is most probable to take place on shore and it is something that is case specific, depending on each oil physical properties, oil/sea-water percentage mix and evaporation of oil components. SAFER SEAS 2007 - BREST 9-12 october 2007

26. Planning • Scaled model validation • Final design • Deployment procedures • Planning & Costing evaluation • Exploitation & promotional activities More information www.difis.eu SAFER SEAS 2007 - BREST 9-12 october 2007