Module 6 2012
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Transcript of Module 6 2012
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Oil & Gas introduction Course for Non-Engineers SEC
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Module 6Dredging
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Oil & Gas introduction Course for Non-Engineers SEC
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1. Capital Dredging vs Maintenance Dredging
Dredging is the under water removal of soil and subsequent transportation to another place, either for deepening or for profitable use
Drivers: Swift population towards coastal areas, Economic growth, World population growth.
DEFINITION:
CAPITAL MAINTENANCE
New IslandsNew Ports
Remove silt/sand from to keep existing water ways to the required depth
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2. Draught
Water depth in the Port or Shipping channel required
Desired depth in Vietnam -12/14m
Tide Vungtau = 3 m Cai Mep/Thi Vai -10 to -13m; TOA/Van Oord 2010
100.000 DWT = 8.000 TEU = approx. 16 m80.000 DWT = 6.000 TEU = approx. 14 m60.000 DWT = 4.000 TEU = approx. 12 m
Soai Rap river / Hiep Phuoc -12? Currently -5/6
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3. Soil conditions
Type of soil and the condition it is in
- Sand (Loose or Compacted)- Silt- Clay (Soft or Stiff)- Gravel- Rock- Coral
Round
Sharp
Silt
Gravel
Modern Soil
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4. Reclamation
Creating Land in the Sea by dumping sand
Maasvlakte 2 Netherlands
Project Vungtau
WHY?
Hai phong
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5. Soil improvement
Improve the bearing capacity from reclaimed land
Kansai Airport sinks 50 cm per year
Methods:- Compaction- Wick/Vertical drains- Vibro floatation- Soil mixing
Consolidation
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6. Beach Nourishment
Replenish sand removed by currents
Break water
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7. Dredging Contractor
THE BIG 4:- Boskalis (Netherlands)- Van Oord (Netherlands)- Jan de Nul (Belgium)- Dredging International (Belgium)
Together hold 60% of the world Dredging market.
VINAWACO
Why they are BIG?:- Buy best equipment (IHC)- In house training school- Large versatile fleet- OPEX over CAPEX
Company to carry out the Dredging work
Link with Offshore?
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8. TSHD
Trailing Suction Hopper Dredger
Long Chau 1969
Trailing is to moving in one direction with something resting on the ground.
Hopper is area to contain the dredged material.
Suction stand for the pump action, vacuuming the seabed.
Hopper capacity can vary from 1.500 m3 up to 34.000 m3.
How long to fill up?Slurrification
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Oil & Gas introduction Course for Non-Engineers SEC
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9. Cutter Dredger
A stationary dredger that can mechanically excavate the seabed
SlurryApplication?
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10. Beaver DredgerSmaller cutter dredger by IHC
Application?
Vietnam owns 9 IHC Beaver Dredgers and about 10 more from other manufacturers
Vietnam has 3 Hopper Dredgers operational between 1.500 m3 and 4.000 m3.
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11. Dipper Dredger
A stationary dredger that uses a bucket to excavate the seabed
Vietnam: Clamshell or Grab Dredging
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12. Excavator
Dredging using an excavator on a pontoon
Application?
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13. Split Hopper
Barge to transport dredged material that can dump quickly by splitting the hull
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14. Multi CatWork boat to assist a cutter dredger with different tasks
- Personnel transfer- Change cutter head or teeth- Hook-up of floating pipe line- Towing Dredger to site
MOVIES
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15. ProductionHow much dry material is dredged per second
m = Density Mixturew = Density Water g = Density In situ
Critical velocity 3 m/s
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16. Suction/Drag head
Suction mouth that is trailing on the seabed at the end of the suction tube
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17. Cutter teeth
Rock / Coral
Sand / Gravel
Clay / Silt
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18. Impeller / Pump Housing
Double walled pump
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19. Discharge pressurePressure at the pressure side of the dredge pump
Pressure
Pressure
Cavitation
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20. Rain bowingEmptying the hopper by re-slurrifying the sand and spraying it from the bow
How Far?
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21. Floating PipelinePipe line to transport mixture from the dredger to the dump site
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22. Booster StationInstallation in the pipeline to bring the pressure back up
Booster
Dumpsite
6 km6 km
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23. Bottom DoorsUnloading the hopper by dumping through bottom doors
Bottom door
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24. Barge LoadingPump the mixture in a barge that is moored next to the Hopper or Cutter
The Dredging Cycle