Deepwater drilling, or deep well drilling, is the process of creating holes in the using a for under the deep sea. There are approximately 3400 deepwater wells in the with depths greater than 150 meters. Deepwater drilling has not been technologically or economically feasible for m.
[pdf] 
These platforms can take the form of either floating semisubmersible platforms or drill ships. The basic idea behind their design is that, once the well has been drilled, much of the production equipment can be mounted on the seafloor and the petroleum pumped to the surface facilities through flexible risers.. .
This platform is essentially a king-sized version of the Sea Star platform, except the tension legs extend from the ocean floor to the platform itself. It experiences more horizontal motion and a certain degree of vertical motion, but it allows oil companies to drill at. .
Finally, if you absolutely need to drill a hole at a depth of 10,000 feet (3,048 meters), then the spar platform is the oil rig for you. With this design, the drilling platform sits atop a giant, hollow cylindrical hull. The other end of the cylinder descends around. .
This approach takes the idea of mounting the wellhead on the seafloor and applies it to even greater depths — 7,000 feet (2,134 meters) or more. Once the well has been drilled by a. .
Deep-sea waters reach nearly freezing temperatures, contain pressures great enough to crack iron casings and are subject to rough, deep-sea currents. Engineers have to design equipment that can stand up to the pressure, while also preventing boiling oil.
[pdf] 
Mobile offshore Drilling Units (MODU) This type of rig is commonly used in connection with oil and/or natural gas drilling. There are more jackup rigs in the worldwide offshore rig fleet than other type of mobile offshore drilling rig. Other types of offshore rigs include semi-submersibles (which float on pontoon-like. .
A jackup rig or a self-elevating unit is a type of mobile platform that consists of a buoyant fitted with a number of movable legs, capable of raising its hull over the surface of the sea. The buoyant hull enables. .
Jackup rigs are so named because they are self-elevating with three, four, six and even eight movable legs that can be extended (“jacked”) above or below the hull. Jackups are. .
A jackup rig is a barge fitted with long support legs that can be raised or lowered. The jackup is maneuvered (self-propelled or by towing) into. .
An early design was the DeLong platform, designed by Leon B. DeLong. In 1949 he started his own company, DeLong Engineering & Construction Company. In 1950 he constructed.
[pdf] 