A method of constructing a semi-submersible vessel using dry dock mating

Abstract

A method of constructing a semi-submersible drilling rig in a shipyard and fully assembling it in a shipyard. The upper hull (1) is built on land adjacent to the dry dock in which the lower hull (2) is built and the joining of the upper and lower hulls is finally done in the dry dock. The upper shell slides to a position above the lower shell, and the lower shell is floated up by injecting water into the dry dock, and the position of the lower shell is adjusted through the ballast tank in the lower shell. Once the upper and lower hulls are in contact alignment, they are permanently welded together, completing the rig assembly in dry dock.

Description

technical field [0001] The present invention relates generally to a method of building an off-shore structure, and in particular to a method of building a semi-submersible drilling rig, vessel or structure (referred to as a "drilling rig") in a dock. Background technique [0002] There is an increasing demand in the market for semi-submersible drilling equipment capable of oil and gas exploration at depths of more than 150 meters. [0003] There are currently two conventional methods of constructing semi-submersible drilling rigs. The first, the so-called "sequential block build-up" method, provides a method of sequentially building semi-submersible rigs "from bottom to top". According to this method, the lower shell of the platform is floating, and the pillars and connecting supports are first erected piece by piece using a shore crane or a floating crane on water. The upper housing which then stands on the lower housing is assembled in the same way. A major disadvantage...

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