Subsea equipment operation arrangement for an offshore platform or vessel

Abstract

A subsea equipment operations arrangement for an offshore platform or vessel includes a working deck with an opening to allow passage of subsea operation equipment to and from a position below the working deck, a lifting structure positioned above the opening to lift and handle heavy subsea operation equipment through the opening, and a system for transporting the heavy equipment laterally over the working deck to and from the opening. The system includes a rail structure on the working deck that supports and guides a movable carrier configured to carry the heavy equipment. The opening extends in a lateral direction from a lifting position below the lifting structure to a point aside the lifting position. A first deck section is movably arranged in the opening, covers a portion of the opening, and includes rail members.

1 . A subsea equipment operations arrangement for an offshore platform or vessel, said arrangement comprising:
 a working deck provided with an opening configured to allow passage of subsea operation equipment to and from a position below the working deck;   a lifting structure configured to lift and handle heavy subsea operation equipment, said lifting structure being positioned above said opening and capable of lifting and lowering the heavy subsea operation equipment through the opening; and   a system for transporting the heavy subsea operation equipment laterally over the working deck to and from the opening, said system comprising a rail structure arranged on the working deck for supporting and guiding a movable carrier configured to carry the heavy subsea operation equipment,   wherein the opening extends in a lateral direction from a lifting position below the lifting structure to a point aside of the lifting position of the lifting structure,   wherein a first deck section is movably arranged in the opening,   wherein the first movable deck section is arranged to cover only a portion of the opening and to be movable along the opening between at least a first position, the lifting position below the lifting structure, and a second position, aside of the lifting position of the lifting structure, and   wherein the first movable deck section is provided with rail members configured to, at least when the first movable deck section is in its first position, be operationally aligned with and thereby form part of the rail structure of the working deck.   
     
     
         2 . The subsea equipment operations arrangement according to  claim 1 , wherein the first movable deck section is substantially flush with the working deck adjacent to the opening. 
     
     
         3 . The subsea equipment operations arrangement according to  claim 1 , wherein the rail members extend across the first movable deck section at an upper surface thereof. 
     
     
         4 . The subsea equipment operations arrangement according to  claim 1 , wherein the first movable deck section is equipped with first and second rail members extending in different directions. 
     
     
         5 . The subsea equipment operations arrangement according to  claim 1 , wherein the first movable deck section is equipped with a cut-out at an edge thereof such that the first movable deck section is capable of, when moved towards the first position with said edge forming a leading edge of the deck section, partly surrounding, by the cut-out, a drill pipe or other drilling equipment extending through the opening. 
     
     
         6 . The subsea equipment operations arrangement according to  claim 1 , wherein the rail structure is arranged to extend to the opening so as to provide for operational alignment with the rail members of the first movable deck section when said first movable deck section is set in a first position. 
     
     
         7 . The subsea equipment operations arrangement according to  claim 1 , wherein said working deck is provided with a drilling tubular storage unit arranged in association with the lifting structure. 
     
     
         8 . The subsea equipment operations arrangement according to  claim 7 , wherein said drilling tubular storage unit is arranged above said opening aside of the lifting position of the lifting structure. 
     
     
         9 . The subsea equipment operations arrangement according to  claim 8 , wherein said drilling tubular storage unit extends across the opening in a direction perpendicular to a longitudinal direction of the opening. 
     
     
         10 . The subsea equipment operations arrangement according to  claim 1 , wherein the arrangement comprises a guiding structure arranged to guide heavy subsea operation equipment as it is lowered or hoisted through the opening, said guiding structure comprising at least one guide member extending in a substantially vertical direction from a position above said working deck. 
     
     
         11 . The subsea equipment operations arrangement according to  claim 10 , wherein the at least one guide member extends to a position below said working deck. 
     
     
         12 . The subsea equipment operations arrangement according to  claim 11 , wherein the at least one guide member extends through the opening. 
     
     
         13 . The subsea equipment operations arrangement according to  claim 12 , wherein the at least one guide member is provided with a removable section that includes a portion of the guide member where it extends through the working deck opening. 
     
     
         14 . The subsea equipment operations arrangement according to  claim 10 , wherein the guiding structure comprises at least a first guide unit movably arranged onto the guide member and vertically movable along the guide member, wherein the first guide unit is securable to a lifting unit configured to carry the equipment to be lowered or hoisted, said first guide unit thereby being capable of guiding said lifting unit along the guide member during lowering or lifting. 
     
     
         15 . The subsea equipment operations arrangement according to  claim 14 , wherein the guiding structure further comprises a second guide unit movably arranged onto the guide member and vertically movable along the guide member, wherein the second guide unit is securable to the equipment to be lowered or lifted and thereby being capable of guiding said equipment along the guide member during lowering or lifting. 
     
     
         16 . The subsea equipment operations arrangement according to  claim 1 , wherein a second deck section is movably arranged in the opening. 
     
     
         17 . The subsea equipment operations arrangement according to  claim 12 , wherein the first and second movable deck sections are arranged in the opening on opposite sides of the at least one guide member, wherein at least one of the first and second movable deck sections is provided with cut-outs at the side facing the at least one guide member, wherein the cut-outs are shaped and positioned in accordance with at least one guide members so that the two deck sections can be moved close together at the at least one guide member. 
     
     
         18 . The subsea equipment operations arrangement according to  claim 1 , wherein the arrangement comprises a lower deck arranged below the working deck. 
     
     
         19 . An offshore platform or a vessel provided with the subsea equipment operations arrangement according to  claim 1 . 
     
     
         20 . The subsea equipment operations arrangement according to  claim 1 , wherein the subsea operation equipment is a blowout preventer (BOP).