There are various types of drilling structures and rigs. They are used in the drilling of petroleum or natural gas both offshore (marine) and onshore (land). The specific requirements determine the type of the rig selected for a particular site. Most of the modern rigs are either of “Jack-knife” Derrick or cantilevered mask type. These rigs can be assembled easily on the ground. You can then use power from hoisting system of from the draw-works to raise them to the vertical position.
Most of the modern drilling structures are made using prefabricated sections which are then assembled on the site. The individual parts of these structures are transported to the site by the use of trucks, helicopters, and barge. There are two categories of the offshore drilling rigs. These are floating and the fixed structure types.
This is a rig which is capable of elevating itself. It is meant for smaller and offshore deposits. It has a floating platform which can be towed into its position by use of barges. This is followed by anchoring its legs to the sea floor for support. Finally, the rig is raised above the surface of the water.
Concrete platform or foundation
The offshore structures which are set using concrete are known for showing excellent performance. These structures are strong and very durable. This makes them more suitable for the arctic environment which is very harsh. This is an environment which carries heavy toptides. These structures are also equipped with storage capacities which are economical for the deep areas. Furthermore, the gravity type platforms do not require additional fixing because they have a large foundation.
These are special rigs which are not anchored to the floor of the sea instead they float on the water surface. These are vessels which are not propelled. It is the burge which contains the drilling equipment. This device is towered to its location. Its hull is then filled with water. It is mainly used for drilling oil shallow areas such as swamps having a depth of less than 12 ft. However, the posted burge can be used for drilling at higher depths up to 20 ft.
These ate types of tower rings which are almost similar to the fixed platforms. They are well anchored to hold the equipment above the water surface. It has a simple design which consists of a flexible and a narrow tower. It can, therefore, withstand any deflections caused by lateral forces.