What are the different platforms of offshore drilling?

Question

What are the different platforms of offshore drilling?

Answer 1

Since the land that is going to be drilled through cannot provide a base for offshore drilling as it does for onshore drilling, an artificial platform must be created. This artificial platform can take many forms, depending on the characteristics of the well to be drilled, including how far underwater the drilling target is. One of the most important pieces of equipment for offshore drilling is the subsea drilling template. Essentially, this piece of equipment connects the underwater well site to the drilling platform on the surface of the water. This device, resembling a cookie cutter, consists of an open steel box with multiple holes in it, dependent on the number of wells to be drilled. This drilling template is placed over the well site, usually lowered into the exact position required using satellite and GPS technology. A relatively shallow hole is then dug, in which the drilling template is cemented into place. The drilling template, secured to the sea floor and attached to the drilling platform above with cables, allows for accurate drilling to take place, but allows for the movement of the platform above, which will inevitably be affected by shifting wind and water currents.

In addition to the drilling template, a blowout preventer is installed on the sea floor. This system, much the same as that used in onshore drilling, prevents any oil or gas from seeping out into the water. Above the blowout preventer, a specialized system known as a 'marine riser' extends from the sea floor to the drilling platform above. The marine riser is designed to house the drill bit and drillstring, and yet be flexible enough to deal with the movement of the drilling platform. Strategically placed slip and ball joints in the marine riser allow the subsea well to be unaffected by the pitching and rolling of the drilling platform.

Answer 2

The first offshore oil production was by scooping from seeps near the shoreline when the tide was down.  This was done in California by the Indians in a place called Carpenteria.

Next, people build piers in the early 20th century off California and Texas.

Next came artifical islands, like those in Long Beach Harbor.

Jack-up rigs began in the 1940's.  A Jack-up rig is where they have a large platform whith all the drilling equipment and legs that can be lowered.  Once the legs hit the sea floor the platform rises above the water.  Limits are about 300 feet water depth.

Platforms came in the 1940's in California and Texas.

Drill ships came in the 1940's and 50's.

Semi-submersibles are like drill ships but are not affected by waves as much becuase the "pontoons" are below the surface.

Tension Leg platforms, which float, and are anchored to the bottom is a recent inovation.