At the end of viable production from subsea wells, an abandonment program may be required to render the well safe, remove the subsea infrastructure and return the seabed to its original condition.
The following operations and selected tools are typical of those encountered by an ROV team during this abandonment phase.
Vessel Campaign Pre-Rig Arrival
If the subsea well/field is old, then it is likely that detailed drawings and models will not be available. A seabed as built survey can be conducted using high resolution cameras, laser scanning and 3D acoustic imaging.
1. Conduct Video As Built Survey of the Field Using the Following TMT Tooling Options
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High quality video surveying using the Surveyor-HD Pro
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Capture high resolution digital stills images using the Tiger Shark Digital Stills Camera
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Gather accurate point measurement data of subsea structures in clear water using the Subsea Laser Scanner
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Gather accurate point measurement data of subsea structures in poor visibility using the Coda Echoscope 3D Sonar
2. High Pressure Cleaning of Subsea Trees and Manifolds
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High pressure cleaning using the TMT 420 Water Blaster Tool
Rig Campaign
1. As Found Survey
2. Tree Cap Running Tool Landout
3. Tree Cap Testing
4. Unlock Tree Cap & Recover Tree Cap Running Tool
5. Clean Gasket Profiles / Tree Connector / Acid Caps & Calcium Wash
6. Clean Guide Posts / Connect Guide Wires
7. Run BOP / Tree Running Tool
8. Valve Ops / Inflow Pressure Testing (ROV) Intervention Skid
9. Disconnect HFL / EFL / FLOT & SIT
10. Connect IWOCS, HFL & EFL
11. Suspend & Kill Well
12. Disconnected Flowhubs / TMT Jacks / Gauges
13. Unlock SST Connector / Subsea Jacks
14. Recover Subsea Tree
15. Clean High Pressure Wellhead & Low Pressure Housing
16. Install Gasket
17. Deploy & Land BOP
18. Hook Up BOP Tensioning System / SST & Intervention Skid
19. BSR Test / High Flow BOP Skid
20. Flush Flowlines
