Method and apparatus for connecting two or more components of an

Abstract

Method and apparatus for joining two or more substructure components of an offshore platform in the water to form a unitary substructure component or jacket. An offshore platform to be located in deep water includes a jacket having at least two sections each composed of at least three legs. The legs are hollow and compartmented and provided with means to adjust the buoyancy of each leg. Each section is launched separately and floated in the at least one leg at or above the water's surface. One of the sections is floated toward a selected shore site until its submerged leg or legs are grounded and the jacket section made negatively buoyant. Another jacket section is floated to the shore site and its legs are aligned with the legs of the already grounded section. The companion legs of each section are then joined to form a unitized jacket. The other jacket section may also be grounded and made negatively buoyant prior to joining the two sections. Support means, such as skids and/or jacks may be used to transform the sea floor at the shore site to a deisred, proper grade or slope for joining the jacket sections. The unitized jacket is floated to the deep water location at which the offshore platform is to be installed and the sections are controllably ballasted to position the jacket upright. The jacket is then anchored to the sea floor and the deck of the platform is placed or stabbed onto the anchored jacket.