LIST AND TYPES OF OF ONSHORE AND OFFSHORE RIG
onshore drilling refers to drilling deep holes under the earth's surface whereas. offshore drilling relates to drilling underneath the seabed. These drilling methods are used in order to extract natural resources – usually oil and gas – from the earth.
ONSHORE RIG.
Land rigs are decided in various power control system
1-Mobile drilling rig.
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2-Heavy drilling which is upto 3000hp.Click here to see photos
OFFSHORE RIG
Barges.
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A barge rig is designed to work in shallow water (less than 20 ft6.096 m
240 in deep). The rig is floated to the drillsite, and the lower hull is sunk to rest on the sea bottom. The large surface area of the lower hull keeps the rig from sinking into the soft mud and provides a stable drilling platform.
240 in deep). The rig is floated to the drillsite, and the lower hull is sunk to rest on the sea bottom. The large surface area of the lower hull keeps the rig from sinking into the soft mud and provides a stable drilling platform.
Submersibles.
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A submersible rig is a barge that is designed to work in deeper water (to 50 ft15.24 m
600 in deep). It has extensions that allow it to raise its upper hull above the water level.
600 in deep). It has extensions that allow it to raise its upper hull above the water level.
Platforms.
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Platforms use a jacket (a steel tubular framework anchored to the ocean bottom) to support the surface production equipment, living quarters, and drilling rig . Multiple directional wells are drilled from the platform by using a rig with a movable substructure. The rig is positioned over preset wellheads by jacking across on skid beams. After all the wells are drilled, the rig and quarters are removed from the platform. Smaller platforms use a jackup rig to drill the wells.
Jackups.
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Jackups are similar to platforms except that the support legs are not permanently attached to the seafloor . The weight of the rig is sufficient to keep it on location. The rig's legs can be jacked down to drill and jacked up to move to a new location. When under tow, a flotation hull buoys the jackup. The derrick is cantilevered over the rear to fit over preset risers if necessary.
Floaters
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Offshore rigs that are not attached to or resting on the ocean bottom are called floaters. These rigs can drill in water depths deeper than jackups or platforms can. They have several special features to facilitate this:
- They are held on location by anchors or dynamic positioning.
- The drill string and riser are isolated from wave motion by motion compensators.
- The wellheads and BOPs are on the ocean bottom and are connected to the rig by a riser to allow circulation of drilling mud.
There are two categories of floaters: semisubmersibles and drill ships.
Semisubmersibles
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Semisubmersibles (also called semis) are usually anchored in place . Although a few semis are self-propelled, most require towing. Because floaters are subject to wave motion, their drilling apparatus is located in the center where wave motion is minimal. Semis are flooded to a drilling draft where the lower pontoons are below the active wave base, thereby stabilizing the motion.
Drill ships
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The drilling apparatus on a drill ship is mounted in the center of the ship over a moon pool, which is a reinforced hole in the bottom of the ship through which the drill string is raised and lowered .The ship can be turned into the oncoming wind or currents for better stability, and it can operate in water too deep for anchors.
Conclusion
Above mention are the list of rigs Including onshore and offshore. Submersible and floating . these rig are becoming very upgraded and full of technology.
Conclusion
Above mention are the list of rigs Including onshore and offshore. Submersible and floating . these rig are becoming very upgraded and full of technology.
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