초록 ▼

An oil production floating support having a mooring device for mooring anchor lines anchoring to the bottom of the sea and bottom-to-surface connection pipes. The device has two mooring buoys having the anchor lines and the bottom-to-surface connection pipes moored respectively thereto. The said two

An oil production floating support having a mooring device for mooring anchor lines anchoring to the bottom of the sea and bottom-to-surface connection pipes. The device has two mooring buoys having the anchor lines and the bottom-to-surface connection pipes moored respectively thereto. The said two mooring buoys being connectable and disconnectable to a turret under which they are fastened, independently of each other.

대표청구항 ▼

1. An oil production floating support, comprising: a hull;a deck;a mooring device for mooring anchor lines at the bottom of the sea and first bottom-to-surface connection pipes extending from said mooring device where they are moored down to the bottom of the sea, said mooring device comprising at l

1. An oil production floating support, comprising: a hull;a deck;a mooring device for mooring anchor lines at the bottom of the sea and first bottom-to-surface connection pipes extending from said mooring device where they are moored down to the bottom of the sea, said mooring device comprising at least one annular mooring buoy, said mooring device being connected reversibly to a turret; andsaid turret comprising at least one watertight tubular structure having a bottom wall assembled in watertight manner to the bottom end of a tubular side wall of said watertight tubular structure, said turret extending in a through cavity passing within the hull of the floating support, said turret being rotatably mounted relative to said hull by means of at least one rolling or friction bearing to allow said floating support to turn about a substantially vertical axis ZZ′ of said turret and of said cavity without causing said mooring buoy to turn relative to the same vertical axis ZZ′; andsecond connection pipes between the top ends of said first bottom-to-surface connection pipes to which they are connected and the deck of the floating support, said second connection pipes passing through the bottom wall of the turret in watertight manner and rising within the cavity to a coupling for coupling a plurality of said second pipes, said coupling being secured to the floating support level with the deck of the floating support, said coupling being of a rotary joint coupling type, being rotatably mounted so as to allow said floating support to turn without turning said coupling, the bottom ends of said second connection pipes under said bottom wall of the turret being connected to the top ends of said first connection pipes by means of connectors co-operating with valves;wherein:said mooring device comprises two mooring buoys disposed coaxially one relative to the other and about the axis of the bottom wall of said turret, a first buoy being an annular buoy having said anchor lines moored thereto, and said annular first buoy including a central orifice containing a second mooring buoy having said first bottom-to-surface connection pipes moored thereto, said second mooring buoy having a top tubular wall within which said valves and connectors are situated at the top ends of said first connection pipes; andsaid floating support includes a connection/disconnection system for connecting/disconnecting said first and/or said second mooring buoy(s) respectively relative to said bottom wall of the turret, enabling each of said respective first or second mooring buoys to be connected/disconnected independently of the other, the connection/disconnection system comprising: two sealing gaskets on the top face of said annular first buoy, said gaskets being coaxial about the axis of the central orifice of said first buoy, defining a first watertight chamber or interstitial annular chamber between the bottom wall of said turret and the top face of said first buoy when said top face of said first buoy is pressed against the bottom wall of said turret; andsaid tubular top wall of said second buoy co-operating with the bottom wall of said turret to define a second watertight chamber referred to as the valve chamber, when a sealing gasket on the top edge of said tubular top wall of the second buoy is pressed against the bottom wall of said turret, against the underface thereof; anda plurality of hoist cables fastened to said mooring buoy; andat least two vent tubes extending vertically inside the turret from a level above a water line to the bottom wall of the turret through which they pass in watertight manner via each of said first and second chambers respectively; andpump means for pumping the water in each of said first and second chambers respectively when said first and second corresponding buoy is respectively pressed against the bottom wall of the turret; andthe dead weight of said first mooring buoy and anchor lines and respectively the dead weight of said second mooring buoy and of said first bottom-to-surface connection pipes is less than the weight of the volume of water corresponding to the volume of said first and second chambers, where Vi=Si×(H0−H2i) in which:H0 is the height of water at the water line;H2i is the height of the top portion of the bottom wall of the turret defining said first chamber or said second chamber respectively;Si is the area of the cross-section of said first chamber or of said second chamber respectively; andi=a for said first buoy and said first chamber and i=b for said second buoy and said second chamber. 2. The floating support according to claim 1, wherein said plurality of said hoist cables extends from winches located on the deck of the floating support or at the top of said turret, above the water line, said cables where appropriate extending inside a plurality of vent and guide tubes extending vertically inside the turret from a level above the water line down to the bottom of the turret through which they pass in watertight manner. 3. The floating support according to claim 1, wherein, for at least one of said first and second buoys, said connection/disconnection system includes at least three said cables and at least three said guide tubes, the bottom ends of said cables being fastened to the top face of said first buoy, or respectively to the top edge of said top tubular wall of said second buoy. 4. The floating support according to claim 1, wherein the diameter of said guide tubes and the immersion depths of the portion of the bottom wall of the turret on which said guide tubes rest, where i=a or b, are such that the inside volume of the guide tubes is less than 15 m3 for a turret having an immersed height H0−H2 within said cavity of at least 20 m. 5. The floating support according to claim 1, wherein said top tubular wall of said second buoy includes, at its bottom end, a bottom wall to which it is assembled in watertight manner, forming the bottom wall of the valve chamber supporting said valves and/or automatic connector portions, and said buoy includes, in its bottom portion, a buoyancy tank constituting a float against the underface of the bottom wall of the valve chamber. 6. The floating support according to claim 1, including at least one said pump, said pump co-operating with a suction pipe passing in watertight manner through said bottom wall of the turret, said suction pipe coming close to the wall of each of said first and second chambers when said first or second buoy is respectively in position pressed against said bottom wall of the turret, and said pump co-operating with a delivery pipe for each of said first and second chambers, each said delivery pipe opening out into said cavity. 7. The floating support according to claim 1, wherein the bottom wall of said turret comprises: a central portion assembled in watertight manner with said side tubular wall of said turret inside it and above the bottom end of said side tubular wall, and a peripheral portion surrounding said central portion, said peripheral portion being offset downwards relative to said central portion in such a manner that the bottom ends of said second link pipes are situated above the bottom end of the side tubular wall of the watertight tubular structure of the turret. 8. The floating support according to claim 1, including reversible mechanical safety locking or retaining means for locking or retaining each of said first and second mooring buoys against the underface of the bottom wall of said turret. 9. The floating support according to claim 8, wherein each of said first or second mooring buoys includes abutments or protective guide members for limiting the flattening of said gaskets and for transferring vertical loads between said first or second buoy and the turret when said first or second buoy is pressed against the bottom wall of said turret, said annular gaskets being compressed between the underface of the bottom wall of said turret and said first or second mooring buoy, said protective guide member being suitable for co-operating with a hinged movable safety latch secured to the underface of the bottom wall of said turret, whereby said first or second mooring buoy is secured to said turret when said safety latch is engaged under said protective guide member. 10. The floating support according to claim 1, wherein said top tubular wall of the second buoy and/or the tubular side wall of the watertight tubular structure of said turret include(s) a filler valve co-operating with filler pipes for putting sea water into communication with the inside of said valve chamber. 11. The floating support according to claim 1, wherein the bottom wall of the turret includes an inspection hatch for inspecting said valve chamber. 12. A method of operating the floating support according to claim 1, wherein a said first or second mooring buoy is connected to the underface against the bottom wall of a said turret by performing the following steps: a) immersing a said first or second buoy, said anchor lines or said first bottom-to-surface connection pipes being moored respectively thereto; andb) securing the bottom ends of hoist cables to said first or second buoy, respectively, said floating support being positioned in such a manner that said first or second buoy, respectively, is substantially on the vertical axis of said cavity; andc) actuating said winches to raise said first or second mooring buoy until said sealing gaskets for said first mooring buoy or said sealing gasket for said second mooring buoy is/are pressed against the underface of the bottom wall of said turret, thereby forming a said first or second chamber respectively that is filled with sea water, said guide tubes co-operating with said first or second chamber respectively being likewise filled with sea water up to a height H0 corresponding substantially to the level of the water surface at the water line; andd) pumping out the water from inside said first or second chamber respectively, using said pump means until the level of water in said guide tubes co-operating with said first or second chamber, respectively, is less than the height H1i, the height H1i being such that the buoyancy corresponding to the weight of the volume of water V1i=Si×(H0−H1i) where i=a for the first buoy and the first chamber and i=b for the second buoy and the second chamber, is greater than the weight of the assembly of said first mooring buoy and said anchor lines for said first watertight chamber or respectively greater than the weight of the assembly of said second mooring buoy and said link pipes for said second watertight chamber. 13. The method according to claim 12, wherein a further step is performed comprising completely emptying said first or second chamber respectively and then making said emptied first or second chamber watertight, and after said first or second chamber has been emptied, the bottom ends of said hoist cables are detached from said first or second mooring buoy, respectively, and retaining means for mechanically retaining said first or said second mooring buoy, respectively, are engaged, thereby securing it to the bottom wall of said turret. 14. The method according to claim 13, wherein a said first or second buoy connected to a said turret is disconnected, wherein after the bottom ends of said hoist cables have been separated from said first or second mooring buoy, the method comprises the following steps: a) causing water to enter at least into said first or second watertight chamber respectively in such a manner that the level of water in said guide tubes co-operating with said first or second chamber respectively comes just above said level H1i with i=a for the first chamber and i=b for the second chamber; andb) for disconnecting said second buoy, unlocking said connectors between said first and second connection pipes; andc) releasing said mechanical retaining means to separate said first or second mooring buoy respectively from said bottom wall of the turret; andd) ending by filling the guide tubes in communication with the chamber, thereby causing said buoy to be disconnected. 15. The method according to claim 14, wherein for disconnecting from said second mooring buoy, the following steps are performed: a) depressurizing said first and second bottom-to-surface connection pipes; andb) filling said second chamber or valve chamber up to said height H2b from the underface of the bottom wall of the turret, and stopping filling as soon as said valve chamber is completely filled with water; andc) releasing said connectors between said first and second connection pipes;d) where appropriate, releasing said mechanical safety latches; ande) continuing to fill said valve chamber so as to fill the guide tubes up to said height H1b. 16. The method according to claim 14, wherein the following steps are performed: 1) disconnecting said second buoy relative to said turret while keeping said first buoy connected to said turret; and2) lowering said second buoy to a certain depth of immersion below said floating support while keeping the first link pipes moored to the second buoy.