Exactly what are oil rigs?
It is a structure that is being used to house workers, oilfield equipment and drill wells for oil and gas. Below are some types of offshore structures:
This kind of rig is made of steel or concrete legs anchored directly to the seabed, supporting a deck with space for drilling rigs, manufacturing facilities and crew quarters. Such structures are, by virtue of their immobility, created for very long term use. Many kinds of structures are used, steel jacket, concrete caisson, etc. Steel jackets are vertical sections made of tubular steel members and are typically piled into the seabed. Fixed platforms are economically practical for setup in water depths up to about 1,700 feet (520 m).
Semi Submersible Platform
The platform has hulls (columns and pontoons) of enough buoyancy to cause the structure to drift, but of adequate weight to keep the structure upright. Semi-submersible is a mobile structure; it can move from place to place. It can be ballasted up or down by changing the amount of flooding in buoyancy tanks; they are typically anchored by combinations of chain, wire rope or polyester rope throughout drilling and manufacturing operations. Although they can also be kept in place by the use of dynamic positioning. Operation area is in water depths from 200 to 10,000 feet (60 to 3,050 m).
As the name of this oil rig states, it is a type of platform that can be jacked up above the sea using its legs that can be lowered like jacks.
Usually used in water depths up to 400 feet (120 m) and some designs up to 170 meters. They are created to move from location to location, and then anchor themselves by deploying the legs to the ocean floor making use of a rack and pinion equipment system on each leg.
A drillship is a ship or vessel that has been fitted with drilling apparatus and devices. It is frequently used for exploratory drilling of new oil or gas wells in deep water but can also be used for scientific drilling. This structure is usually prepared with a dynamic positioning system to preserve the position over the well. They can drill in water depths of approximately 12,000 feet (3,660 m).
Tension Leg Platform
TLPs is a drifting platform tied to the seabed in a manner that removes most vertical motion of the structure. This structure is used in water depths of about 6,000 feet (2,000 m).
There are many other kinds of offshore structures that have been created for the purpose of Oil & Gas exploration and drilling.