Buoy For The Processing Of Production Fluids

Abstract

A buoy comprising a hydrocarbon processing facility for processing production fluids received from an offshore well, the facility being disposed in a portion of the buoy that is submerged below the waterline, has a pressure relief channel for venting gas above the waterline. The pressure relief channel is in fluid communication with a chamber in the buoy which may contain the processing facility, or other equipment presenting an explosive hazard, and is the only conduit through which high pressure is exhausted. In particular, the pressure relief channel can contain the effects of an over-pressurisation event within the chamber such as ignition of flammable gas, and mitigate structural damage to the buoy.

We claim: 
     
         1 . A buoy for the processing of production fluids from an offshore well, the buoy comprising a hydrocarbon processing facility adapted to process production fluids received from the offshore well, the hydrocarbon processing facility being submerged below the operating waterline of the buoy, wherein the buoy has a pressure relief channel adapted to relieve pressure within a chamber below the operating water line of the buoy in the event of over-pressurisation within the chamber, the pressure relief channel being in fluid communication with chamber and wherein the pressure relief channel is adapted to vent gas pressure above the operating waterline of the buoy. 
     
     
         2 . A buoy as claimed in  claim 1 , wherein the chamber is a gas tight chamber. 
     
     
         3 . A buoy as claimed in  claim 1 , wherein the chamber contains the hydrocarbon processing facility. 
     
     
         4 . A buoy as claimed in  claim 1 , wherein the chamber is divided into separate rooms that are linked to one another by fluid conduits allowing gas flow between the rooms within the chamber, and wherein at least two of the rooms incorporate hydrocarbon processing equipment. 
     
     
         5 . A buoy as claimed in  claim 1 , wherein the pressure relief channel is routed through sequential decks of the buoy parallel to the vertical axis. 
     
     
         6 . A buoy as claimed in  claim 1 , wherein the upper end of the pressure relief channel comprises a cover adapted to close an upper end opening of the pressure relief channel; and wherein the cover is adapted to release from the upper end opening during an over-pressurisation event within the chamber. 
     
     
         7 . A buoy as claimed in  claim 1 , wherein the pressure relief channel is adapted to mitigate structural damage to the buoy resulting from an over-pressurisation event in the chamber. 
     
     
         8 . A buoy as claimed in  claim 1 , wherein the pressure relief channel is at least partially lined with a material comprising a metal. 
     
     
         9 . A buoy as claimed in  claim 1 , wherein the pressure relief channel is at least partially lined with a composite material. 
     
     
         10 . A buoy as claimed in  claim 1 , wherein the buoy has multiple layers of decks and comprises a central access shaft adapted to facilitate movement of machinery and other components between upper and lower decks of the buoy, wherein the central access shaft extends parallel to a vertical axis of the buoy from a lower deck of the buoy on which the hydrocarbon processing facility is disposed to an upper deck of the buoy above the waterline. 
     
     
         11 . (canceled) 
     
     
         12 . (canceled) 
     
     
         13 . (canceled) 
     
     
         14 . A buoy for the processing of production fluids from an offshore well, the buoy comprising a hydrocarbon processing facility adapted to process production fluids received from the offshore well, the hydrocarbon processing facility being submerged below the operating waterline of the buoy, the buoy having a fluid flowline connector interface adapted to connect a fluid flowing from a marine riser to admit production fluids from a well into the hydrocarbon processing facility. 
     
     
         15 . A buoy as claimed in  claim 14 , wherein the fluid flowline connector interface penetrates a wall of the buoy below the operating waterline. 
     
     
         16 . A buoy as claimed in  claim 14 , wherein the fluid flowline connector interface is protected from damage by a protective covering disposed on the buoy. 
     
     
         17 . A method of venting gas from an offshore production buoy in the event of over-pressurisation, the method comprising channelling the gas through a pressure relief channel, wherein the pressure relief channel is in fluid communication with a chamber disposed below the operating waterline of the buoy and venting the gas to atmosphere from the pressure relief channel above the operating waterline of the buoy. 
     
     
         18 . A method as claimed in  claim 17 , wherein the cavity contains a hydrocarbon processing facility. 
     
     
         19 . A method as claimed in  claim 17 , the method including releasing a closure member covering an external opening of the pressure relief channel when the pressure within the pressure relief channel rises above a threshold pressure. 
     
     
         20 . A method as claimed in  claim 17 , the method including locating the hydrocarbon processing facility and apparatus in one location and directing the pressure relief channel vertically upwards from this one location. 
     
     
         21 . A method as claimed in  claim 17 , the method including distributing plant and other equipment necessary for functionality of the buoy around a central access shaft, wherein the central access shaft extends vertically from the a lower deck of the buoy below the operating waterline to an upper deck disposed above the operating waterline. 
     
     
         22 . A method as claimed in  claim 17 , the method including flowing production fluids from a well into the hydrocarbon processing facility, stabilising the production fluids by heating them to flash off gas, and utilising the gas that is flashed off to at least partially fuel heat and power generation within the buoy. 
     
     
         23 . A method as claimed in  claim 17 , the method including transiently storing the processed hydrocarbons within the buoy during the processing phase. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled)