Semi-Submersible Oil Drilling Platform (DP installations) is a type of drilling rig used in the exploration and production of oil in the high seas.
The need to use Dynamic Industries Ingleside TX at sea depths exceeding the capabilities of gravity-based bases led to the creation of semi-submersible drilling rigs in the early 1960ies. It is applied at drilling depths of up to 10,000 meters and the depth of the sea up to 3,000 meters.
A semisubmersible oil-drilling platform cannot move for KSK Loadout, as it is held by anchors weighing about fifteen tons. Nevertheless, maintaining a constant load on the floating structure is a difficult and expensive operation. Therefore, on some platforms, such as Deepwater Horizon, a computerized dynamic system for positioning is used, which, with the help of powerful underwater engines, constantly keeps the platform in a certain place, with an accuracy of several meters.
Application of technology
Semi-submersible drilling platforms are used in exploratory drilling on offshore oil and gas structures and fields in water areas from depths of 90-100 m, when the use of SPMS becomes economically unjustified, to depths of 200-300 m and more.
Semi-submersible drilling platforms consist of an upper shell, stabilizing columns, and lower pontoons. The peculiarity of the structure of the installation when it is immersed in water is a sharp reduction in the waterline’s action area, which leads to a decrease in the wave loads on the installation.
The working (upper) deck is usually a 3-, 4-, 5- and more-carbon structure, on which are placed 2- and 3-tier waterproof superstructures for crew’s accommodation, as well as power and technological blocks, storage facilities, and other equipment.
Stabilizing columns of the semisubmersible drill string are divided into watertight compartments, in which material warehouses, pump compartments, chain boxes, and other equipment are located. The compartments of stabilizing columns are located near the waterline, sometimes filled with polyurethane foam. In the lower pontoons and stabilizing columns, there are tanks full of ballast and industrial water, fuel, oil, etc.