Offshore wellhead platform

Abstract

An unmanned offshore wellhead platform 10 for use in the oil and gas industry, the platform comprising: riser hang-off equipment 13 for connection to at least one riser for flow of hydrocarbon fluids from at least one well; and process equipment 14 for processing the hydrocarbon fluids to produce processed or part processed hydrocarbon fluids for storage and/or transport to another installation, wherein all of the process equipment 14 is on a single process deck 12 of the platform 10.

1 . An unmanned offshore wellhead platform for use in the oil and gas industry, the platform comprising:
 riser hang-off equipment for connection to at least one riser for flow of hydrocarbon fluids from at least one well; and   process equipment for processing the hydrocarbon fluids to produce processed or part processed hydrocarbon fluids for storage and/or transport to another installation,   wherein all of the process equipment is on a single process deck of the platform.   
     
     
         2 . A platform as claimed in  claim 1 , wherein the single process deck is the main deck of the platform and there are no other decks for equipment relating to the processing or handling of hydrocarbon fluids. 
     
     
         3 . A platform as claimed in  claim 2 , wherein there are no other decks aside from more decks provided for the purpose of facilitating weather protection, materials handling and/or access to the single process deck. 
     
     
         4 . A platform as claimed in  claim 1 ,  2  or  3 , wherein the processing equipment includes equipment for processing or part processing the hydrocarbon fluids, such as equipment for water handling and separation for re-injection, hydrocarbon separation, and/or gas reinjection equipment such as via ESP. 
     
     
         5 . A platform as claimed in any preceding claim, comprising ancillary equipment required for operation of the wellhead platform, wherein all of this ancillary equipment is located on the single process deck along with the process equipment. 
     
     
         6 . A platform as claimed in  claim 5 , wherein the ancillary equipment comprises an electrical cabinet holding an electrical control system for the wellhead platform. 
     
     
         7 . A platform as claimed in any preceding claim, wherein the single process deck is arranged to allow personnel to access the process equipment for maintenance purposes via a walkway for enabling personnel to access the process equipment, wherein the walkway also forms an evacuation route for personnel to leave the platform single process deck in the event of an emergency such as a fire. 
     
     
         8 . A platform as claimed in any preceding claim, wherein the single process deck is arranged with the riser hang-off equipment at the centre. 
     
     
         9 . A platform as claimed in any preceding claim, wherein the processing equipment is located at an outer part of the single process deck in one or more location spaced apart from the centre of the deck. 
     
     
         10 . A platform as claimed in any preceding claim, wherein the single process deck includes one or more materials handling device(s) for movement of materials about the plane of the single process deck. 
     
     
         11 . A platform as claimed in any preceding claim, comprising a weather deck for shielding the single process deck from the weather. 
     
     
         12 . A platform as claimed in  claim 11 , wherein the weather deck supports a crane for lifting heavy items to and from the single process deck. 
     
     
         13 . A platform as claimed in  claim 11  or  12 , wherein the weather deck and the single process deck are arranged such that there is access to certain equipment on the single process deck from above. 
     
     
         14 . A platform as claimed in  claim 13 , wherein the weather deck does not fully cover the single process deck and instead the single process deck extends horizontally outward below the weather deck at the locations of said certain equipment. 
     
     
         15 . A platform as claimed in  claim 13  or  14 , comprising a first crane on the single process deck for moving equipment in the plane of the single process deck; a second crane on the weather deck for lifting equipment vertically from the single process deck; and a laydown area on the single process deck that is accessible to both the first crane and the second crane. 
     
     
         16 . A platform as claimed in any preceding claim, comprising an access level beneath the single process deck allowing for access for maintenance. 
     
     
         17 . A platform as claimed in any preceding claim, comprising a single process deck holding all of the process equipment on the platform, a weather deck located above the single process deck, an access deck located below the single process deck, and no further decks or floor levels. 
     
     
         18 . A platform as claimed in any preceding claim, comprising:
 equipment and piping associated with the oil and gas installation;   a hydrocarbon inventory including hydrocarbons in the equipment and piping; and   no mechanism for emergency depressurisation of a hydrocarbon inventory of the platform in the event of a fire;   wherein the size of the platform is restricted such that evacuation of personnel can be achieved prior to escalation of a fire due to the lack of depressurisation; and   the platform is arranged to permit a fire to escalate by combustion of the hydrocarbon inventory after evacuation of the personnel.   
     
     
         19 . A platform as claimed in  claim 18 , comprising isolation valves arranged to isolate the hydrocarbon inventory of the platform from external hydrocarbons in the event of a fire. 
     
     
         20 . A platform as claimed in  claim 18  or  19 , wherein the restricted size is such that evacuation of personnel can be achieved within an evacuation time that is at most 15 minutes, optionally 10 minutes or below. 
     
     
         21 . A platform as claimed in any preceding claim, wherein the unmanned platform has no provision of facilities for personnel to stay on the platform, for example there may be no shelters for personnel, no toilet facilities, no drinking water, no personnel operated communications equipment, no heli-deck and/or no lifeboat; and/or wherein the unmanned platform is arranged such that personnel are required to be present for fewer than 10,000 maintenance hours per year. 
     
     
         22 . A platform as claimed in any preceding claim, comprising a gangway and/or a bridge for connecting the platform to a vessel and/or another platform. 
     
     
         23 . A platform as claimed in  claim 22 , wherein the platform includes passive fire protection for at least some of the equipment on the platform; wherein the platform is arranged to have an evacuation time of at most 15 minutes or less using one or more evacuation route(s) via the gangway or bridge allowing personnel to escape to a vessel or to another platform; and wherein the passive fire protection is installed on the equipment and/or piping in order to prevent escalation of the fire that would create a risk to personnel on the evacuation route(s) during a determined maximum evacuation time.