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Ocean General Overview05-1c-DH-1X

Offshore Training Report

10th Feb 2007 – 9th Mar 2007

Nguyễn Việt Hùng

Exploration Group

Japan Vietnam Petroleum Company

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Ocean General is a semi-submersible rig owned by Diamond Offshore Drilling. It was used for Nam Côn Sơn Basin as there is a deep water area (245m), out of jack-up rig range.

Tension leg Production Platform Drilling vessel Semi-submersible rig

Jack-up rig

Jacket Production Platform Onshore rig

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Main parts of Ocean General

Cranes

Derrick

Helideck

Main deck

Anchor Controllers

Life boat

Tensioners

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1. DerrickIt is 50m high, can load 250 tons drill string.

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Derrick’s function is to support rotating systems loading and drilling equipments’ traveling.

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Drill floor is under derrick, it is the place where floormen and driller work.

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2. Main deckFor units, equipments occupied and workers do their jobs.

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3. Helideck deckSupports taking off and landing of helicopter. Its diameter is 22m.

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4. CraneThere are always 2 cranes on each rig. They are for transporting containers, equipments and people within the rig and to supply boat.

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5. Ballasts

A typical part of a semi-sub rig, they are floatable buoys with occupied water inside.

Ballasts

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6. Tensioners

It is available on a semi-sub rig only. It consist of hydraulic cylinders and cables system.

Tensioners work automatically and continously to minimize the rig’s heave due to sea wave.

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7. Anchors and anchor controllers

Each semi-sub rig has 8-12 anchors. They keep the rig’s stability and were handled by Anchor Handling Vessel.

The anchor controllers were controlled automatically by Dynamic Balance System to balance the tension of each opposite anchor cables.

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8. Generators and Power supply systemThere are 4 engines use diesel to ensure the power for system operation and other life activities.

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9. Circulating system

Circulates the drill mud into the bore hole and support mud logging job.

This system will be regarded with more details in following section.

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10. Transportationa. Helicopter:

For personnel changeout and moving small items. It takes 1.5 hour from Vũng Tàu Airport to Ocean General by helicopter.