Definition: “Jack-up” is the name given to a category of offshore drilling rigs. These Jack-up rigs are easy to recognize by their long steel frame legs supporting the platform.
Comments: There are three basic types of offshore drilling rigs, Jack-up, Drilling ships and Semi-submersible. These types have different design and costs, the choice depends on the drilling conditions such as the water depth.
In that respect the Jack-up drilling rigs will be used in shallow water where the water depth will not exceed 160 meters (492ft).
Once a jack-up rig is towed to the drilling site, three or four ‘legs’ are lowered until they rest on the sea bottom. This allows the working platform to rest above the surface of the water, as opposed to a floating barge. These rigs are typically safer to operate than drilling ships, as their working platform is elevated above the water level.