Exxon Production Research Company

Stephen D Vaughn

George F Davenport

Ray L Steinmetz

John B Wardell

Robert B Campbell

A method of installing an integrated deck onto an offshore platform substructure. The integrated deck is held by a support structure on a barge and transported to a preinstalled offshore platform substructure which is adapted to receive the barge and allow aligning of the integrated deck with the substructure for mating operations. Once the barge is positioned within the substructure, tethers are connected between the barge and anchoring foundation elements to moor the barge. Then the tethers are tensioned to minimize both vertical movement and lateral movement caused by wave action. Mating of the integrated deck and the substructure proceeds while tension loads in the tethers are maintained.

Method of offshore platform construction using a tension-moored barge

An improved apparatus is disclosed for setting a deck structure or other marine superstructure using a barge mounted cantilevered support structure. The cantilevered support structure is attached at one end of a floating vessel. The cantilevered support structure extends past the edge of the vessel and, in one embodiment, includes means for rotating parallel support members about the deck of the floating vessel permitting the cantilevered support structure to be raised and lowered while it remains substantially parallel with the top of the offshore platform enabling the superstructure to engage the top of a previously installed offshore platform in a synchronized manner. Alternatively, this superstructure may be aligned directly over the platform. A cantilevered drilling rig is then aligned over the cantilevered support structure and used to lift the deck structure or marine superstructure, permitting the vessel and cantilevered support structure to move. The drilling rig is then used to lower the marine superstructure onto the top of the previously installed offshore platform.

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Houston, TX, United States of America

Stephen D Vaughn