Patent Application
20220009595
The present invention concerns a floating fluid loading/offloading structure moored in a body of water, having
Such a floating structure is for example a Floating Storage and Regasification Unit (FSRU) able to receive liquid natural gas (LNG) from a LNG tanker and to gasify the LNG to form a natural gas to be exported onshore.
In variant, the floating structure is a Floating Liquefied Natural Gas unit (FLNG) able to receive natural gas from a reservoir and to liquefy the natural gas to form LNG.
In another variant, the floating structure is a Floating Production Storage and Offloading unit (FPSO) intended to receive fluid produced from the bottom of the body of water for processing the hydrocarbons.
Such structures can be spread moored i.e. moored with mooring lines at least at the four corners of the hull. The mooring lines protrude from the hull away to the bottom of the body of water into which they are anchored.
Such structures are relatively easy to anchor. They are moreover very stable. Nevertheless, these structures are not entirely satisfactory. The structures cannot be easily freed from their mooring equipment, in case the atmospheric conditions become inappropriate for fluid offloading. Moreover, when the loading/offloading of the fluid has to be carried out side by side with a ship, the mooring lines prevent access of the ship in the vicinity of the hull.
To overcome this problem, WO2006/101395 discloses a floating structure which is moored totally underwater. Mooring lines extend from the bottom wall of the hull to the bottom of the body of water.
Nevertheless, underwater mooring is quite complex. The connection of the mooring lines to the hull requires using specific equipment, divers and/or ROV to put in place the mooring lines. Similarly, specific equipment, divers and/or ROV must also be used to disconnect the mooring lines in case of necessity.
The underwater mooring requires many specific equipment and structural modifications on the hull. Hence, it is not very economical and it makes the structure not easily disconnectable.
One aim of the invention is therefore to provide a floating fluid loading/offloading structure which is robustly moored on the bottom of the body of water, but which remains easily disconnectable and economically attractive, while allowing an easy approach of a loading/offloading ship close to the structure.
To this aim, the subject-matter of the invention is a floating fluid loading/offloading structure of the above-mentioned type, characterized in that the mooring lines of the first group are connected above the surface of the body of water on the first side of the hull, the space facing the second lateral wall being free of mooring lines.
The floating structure according to the invention may comprise one or more of the following features, taken alone or according to any technical feasible combination:
The invention also relates to a fluid loading/offloading installation comprising:
The fluid loading/offloading installation according to the invention may comprise one or more of the following features, taken alone or according to any technical feasible combination:
The invention also concerns a method of installing a floating fluid loading/offloading structure moored in a body of water comprising the following steps:
The invention also relates to a process for loading/offloading a fluid comprising the following steps:
The invention will be better understood based on the following description, given solely as an example, and made in accordance with the appended drawings, in which:
A first loading/offloading installation 10 according to the invention, placed in a body of water 12, is shown schematically in
The fluid is for example a hydrocarbon fluid such as liquid natural gas (LNG). The liquid natural gas is intended to be transferred in the installation 10 and conveyed from the installation 10 to a network after regasification (not represented) to be used by users.
The body of water 12 is here a lake, a river, a sea, and/or an ocean. The depth of the body of water, in the vicinity of the installation is comprised between 15 m and 150 m.
The loading/offloading installation 10 here comprises a fluid collecting and/distributing structure 16, a floating fluid loading/offloading structure 18 according to the invention, and at least a pipe 20 connecting the floating fluid loading/offloading structure 18 and the fluid collecting and/or distributing structure 16.
In the example shown in
In a variant (not shown), the fluid collecting and/or distributing structure 16 is a floating structure such as spread moored barge.
The fluid collecting and/or distributing structure for example comprises at least a fluid distributor 24 intended to collect and/or distribute a fluid from the pipe 20 to an external network.
The floating fluid offloading/loading structure 18 comprises a hull 30, floating at the surface of the body of water 12, at least a fluid processing unit 32, carried by the hull 30 and a mooring equipment 34 able to moor the hull 30 at a specific position in the body of water 12.
In this example, the floating fluid loading/offloading structure 18 is a FSRU (Floating Storage and Regasification Unit). The fluid processing unit 32 comprises at least a regasification unit able to transform liquid natural gas into a gas form.
In a variant (not shown), the floating fluid loading/offloading structure 18 is a FLNG (Floating Liquefied Natural Gas), intended to receive fluid gaseous hydrocarbons produced from the bottom of the body of water to produce LNG. The fluid processing unit 32 comprises a liquefying unit able to liquefy natural gas into LNG.
In another variant (not shown), the floating fluid loading/offloading structure 18 is a FPSO (Floating Production Storage and/offloading) intended to collect liquid and gaseous hydrocarbons from the bottom of the body of water 12. The fluid processing unit 32 is then a purification and treatment unit of the liquid and gaseous hydrocarbons.
As shown in
The hull 30 comprises a bottom wall 44, located below the first lateral wall 36 and the second lateral wall 40, and at least a deck 46. The first lateral wall 36, and the second lateral wall 40 are partially immersed in the body of water 12.
The first lateral wall 36 and the first side 38 are located facing the fluid collecting and/or distributing structure 16.
The second wall 40 and the second side 42 are located opposite the fluid collecting and/or distributing structure 16. The ship 14 is able to approach the hull 30 on the second side 42 and to moor to the hull 30 along the second side 42, as it will be described later.
The first lateral wall 36 and the second lateral wall 40 are partially in contact with the body of water 12. They define the most exterior surface of the hull 30 on their respective side 38, 42.
The bottom wall 44 connects the first lateral wall 36 to the second lateral wall 40. The bottom wall 44 is totally immersed in the body of water 12, below the surface. In the figures, the bottom wall 44 is represented flat, however it can be of any shape.
The first lateral wall 36, the second lateral wall 40 and the bottom wall 44 together define an inner space 48 of the hull 30, which is upwardly closed by the deck 46.
The deck 46 is here located above the surface of the body of water 12. It for example comprises a guard-rail at its periphery 50.
The fluid processing unit 32, as described above, is located on the deck 46 and/or in the inner space 48. It advantageously comprises at least a fluid reservoir and fluid processing equipment, such as pumps, evaporators, heat exchanger, separators, compressors . . .
The first side 38 of the hull 30 is generally delimited inwards by a vertical plane containing the longitudinal axis A-A′, downwards by the bottom wall 44, and outwards by the first lateral wall 36.
The second side 42 of the hull 30 is generally delimited inwards by a vertical plane containing the longitudinal axis A-A′, downwards by the bottom wall 44, and outwards by the second lateral wall 40.
The mooring equipment 34 comprises a first group 60 of mooring lines 62, extending laterally apart from the hull 30 from the first side 38, and a second group 64 of mooring lines 66, extending laterally apart from the hull 30, away from the second side 42 of the hull 30.
The mooring equipment 34 further comprises, for the mooring lines 62 of the first group 60, at least a tensioning winch 68 and for each mooring line 62, at least a deck stopper 70.
The mooring equipment 34 comprises, for the mooring lines 66 of the second group 64, at least a pad eye 72 connected to the bottom wall 44 of the hull 30, or to the first lateral wall 36 and apart from the second lateral wall 40.
Each mooring line 62 of the first group 60 extends in a catenary shape from a first point 74 located above the surface of the body of water 12 on a first side 38 of the longitudinal axis A-A′ to a second point 76 anchored in the bottom 22 of the body of water 12, laterally away from the first lateral wall 36 on the first side 38 of the hull 30. Each mooring line 62 extends facing the first lateral wall 36 away from the first lateral wall 36.
Each mooring line 62 is preferably formed of a rope and/or of a chain.
The first point 74 of each mooring line 62 is preferably located on the deck 46, and is maintained on the deck 46 with a deck stopper 70. The second point 76 is preferably provided with an anchor inserted in the bottom 22 of the body of water 12.
At least the mooring line 62, preferentially at least three mooring lines 62, extend from a first point 74 located in the vicinity of the first hull end 37.
The second point 76 of each mooring line 62 extending from the vicinity of the first hull end 37 protrudes away from the hull 30 beyond the first end 37, in projection on the longitudinal axis A-A′.
Preferably, in projection in a horizontal plane (see
At least one mooring line 62, preferentially at least three mooring lines 62, also extends from a first point located in the vicinity of the second hull end 39.
The second point 76 of each mooring line 62 extending from the vicinity of the second hull end 39 protrudes away from the hull 30 beyond the second end 39 in projection on the longitudinal axis A-A′.
Preferably, in projection in a horizontal plane (see
Each mooring line 66 of the second group 64 extends in a catenary shape from a first point 78 located below the surface of water, away from the second lateral wall 40 and from the first lateral wall 36, to a second point 80 anchored in the bottom 22 of the body of water 12, laterally away from the second lateral wall 40 on the second side 42 of the hull 30.
Each mooring line 66 is preferably formed of a rope and/or of a chain.
Preferentially, the first point 78 of each mooring line 66 is connected to the pad eye 72, below the bottom wall 44, laterally away from the second lateral wall 40. The second point 80 is preferably provided with an anchor inserted in the bottom 22 of the body of water 12.
At least the mooring line 66, preferentially at least three mooring lines 66, extend from a first point 78 located in the vicinity of the first hull end 37.
The second point 80 of each mooring line 66 extending from the vicinity of the first hull end 37 protrudes away from the hull beyond the first hull end 37, in projection on the longitudinal axis A-A′.
Preferably, in projection in an horizontal plane (see
At least one mooring line 66, preferentially at least three mooring lines 66, extend from a second point 80 located in the vicinity of the second hull end 39.
The second point 80 of each mooring line 66 extending from the vicinity of the second hull end 39 protrudes away from the hull 30 beyond the second hull end 39, in projection on the longitudinal axis A-A′.
Preferably, in projection in a horizontal plane (see
Each mooring line 66 of the second group 64 extends to a second point 80 located away from the hull 30 beyond the second lateral wall 40 on the bottom of the body of water 12.
Hence, each mooring line 62 of the first group 60 protrudes away from the hull 30 on the first side of the hull 38, and each mooring line 66 of the second group 64 protrudes away beyond the second lateral wall 40 of the hull 30.
The first point 78 and the second point 80 of each second mooring line 66 are located below the body of water 12.
Hence, the space 82 located facing the second lateral wall 40 away from the hull 30 is free of mooring lines 66. The space 82 is therefore totally available for the approach and mooring of a ship 14, without interference with any mooring lines and the ship 14.
In reference to
The deck stopper 70 comprises a channel 90 receiving and guiding each mooring line 66, and a blocker 92 selectively operable between an inactive configuration, in which the mooring line 66 is free to translate in the channel 90, and a blocking configuration, in which the mooring line 62 is blocked in the channel 90.
Preferentially, the mooring equipment 34 comprises at least a pad eye 72 located in the vicinity of the first hull end 37, and at least a pad eye 72, located in the vicinity of the second hull end 39.
In the example of
As shown in
In the example of
The ship 14 is able to position itself in the space 82 facing the second wall 40. It is able to be moored to the hull 30. The hull 30 and/or the ship 14 are equipped with a discharging equipment comprising at least a fluid conveying element 98 such as but not limited to a marine loading arm of hose, a pipe, a hose, or/and a riser.
The set-up of the loading/offloading installation 10 will be now briefly described. Initially, a first point 78 on a first section of each mooring line 66 of the second group 64 is attached underwater to the pad eye 72.
A second section of each mooring line 66 of the second group 64 is laid on the bottom of the body of water 12 and it is anchored at a second point 80 on the bottom of the body of water 12, at a position defined above.
Then, the respective free ends of the first section and of the second section of each mooring line 66 are connected together. The mooring line 66 then adopts a catenary shape.
Subsequently, each mooring line 62 of the first group 60 is laid in the body of water 12 and is anchored at its second point 76 in the bottom 22 of the body of water 12. A buoy (not shown) is placed around the first point 74 of each mooring line 62.
Then, the free end of each mooring line 62 of the first group 60 is pulled by the tensioning winch 68 to be inserted into the deck stopper 70 in its inactive configuration. When the mooring line 62 is sufficiently tensioned so that the hull 30 occupies its nominal position, the blocker 92 of the corresponding deck stopper 70 is activated and the first point 74 of each mooring line 62 of the first group 60 is blocked on the deck 46.
In use, a ship 14 containing fluid, in particular a LNG tanker, can freely approach the hull 30 on the second side 42, without interfering with mooring lines 66 or with any other mooring equipment 34. The ship 14 preferentially adopts an orientation parallel to the longitudinal axis A-A′ of the hull 30. The hull 30 and the ship 14 are then placed side by side. Then, the ship 14 is advantageously moored to the hull 30 and the fluid conveying element 98 is put in place.
In the example of a FSRU, the fluid, preferentially LNG, circulates from the ship 14 reservoir to the fluid processing unit 32, to be loaded in a reservoir of the fluid processing unit 32. Then, the fluid is evaporated and is conveyed towards the fluid collecting and/or distributing structure 16 through the pipe 20.
When the ship 14 has discharged all the required fluid, it is able to move away from the hull 30 without interference with mooring lines 62.
Thanks to the invention, the connection/disconnection of the hull 30 to its mooring equipment 34 is very simple to carry out, since all the mooring lines 62 of the first group 60 located on the first side 38 can easily be connected/disconnected from the surface. Only the mooring lines 66 of the second group 64 must be disconnected from under water. Moreover, there is no interference between the ships 14 intended to load/unload the fluid and the hull 30, allowing a safe and efficient approach of the ship towards the hull 30.
A second installation 110 according to the invention is shown in
The second installation 110 differs from the first installation 10 by the configuration of the second group 64 of mooring lines 66.
Each mooring line 66 of the second group 64 is connected to the hull 30 at a first point 78 located on the first side 38 of the hull 30. The first point 78 is preferentially located on the deck 46, above the surface of the body of water 12.
The mooring equipment 34 of the second installation 110 further differs from the mooring equipment 34 of the first installation 10 in that it comprises a deck stopper 70 for each mooring line 66 of the second group 64, in addition to the deck stopper 70 for each mooring line 62 of the first group 60.
Moreover, the mooring equipment 34 comprises a tensioning winch 68 which can be specific to the mooring lines 66 of the second group 64, or which can be the same as the mooring lines 62 of the first group 60.
Preferentially, the mooring equipment 34 further comprises, for each mooring line 66 of the second group 64, a bending shoe 112 fixed on the first lateral wall 36 and/or on the bottom wall 44, in the vicinity of the transition between the first lateral wall 36 and the bottom wall 44.
The bending shoe 112 provides an external guiding surface 114 onto which each mooring line 66 of the second group 64 is able lay. The guiding surface 114 has a controlled radius of curvature, e.g. comprised between 1 m and 10 m.
Hence, each mooring line 66 of the second group 64 has a bent section 116 extending from the first point 78 downwardly along the first lateral wall 36 to the bending shoe 112, from the bending shoe 112 below the bottom wall 44, and beyond the second lateral wall 40 to the second point 78.
As in the first installation 10, the space 82 located facing the second lateral wall 40 is therefore free of mooring lines 66.
The setup of the second installation 110 is particularly easy, since it does not require the use of a diver to connect the mooring lines 66 of the second group 64. As for the mooring lines 62 of the first group 60, the mooring lines 66 of the second group 64 are laid in the water, with a buoy at the first point 78. Then, the hull 30 is passed above the mooring lines 66 of the second group 64. The free ends of the mooring lines 66 are pulled to the deck 46 on the first side 38 of the longitudinal axis A-A′, advantageously by using a tensioning winch 68.
Each mooring line 66 of the second group 64 is inserted in the channel 90 of a deck stopper 70 with the blocker 92 in the inactive configuration and is progressively tensioned. When the tensioning of the mooring line 66 is sufficient, the blocker 92 is activated to block the first point 78 of the mooring line in the channel 90.
Thereafter, the mooring lines 62 of the first group 60 are put in place, as described above for the first installation 10.
The second installation 110 according to the invention is therefore very easy to connect or disconnect.
A third installation 120 according to the invention is shown in
The third installation 120 differs from the first installation 10 by the configuration of the second group 64 of mooring lines 66.
Each mooring line 66 of the second group 64 is connected to the hull 30 at an underwater stopper 122 located on the first side 38 or the bottom side 40 of the hull 30. The first point 78 is preferentially located on the deck 46, above the surface of the body of water 12.
The mooring equipment 34 of the third installation 122 further differs from the mooring equipment 34 of the first installation 10 in that it comprises a split pipe 124 for each mooring line 66 of the second group 64, connected to the underwater stopper 122. The split pipe 124 guides the first chain link i.e. the chain link at first point 78 on each mooring line 66 of the second group to its position in the underwater stopper 122.
Moreover, the mooring equipment 34 comprises a tensioning winch 68 which can be specific to the mooring lines 66 of the second group 64, or which can be the same as the mooring lines 62 of the first group 60.
As in the first installation 10, the space 82 located facing the second lateral wall 40 is therefore free of mooring lines 66.
The setup of the third installation 120 is particularly easy, since it does not require the use of a diver to connect the mooring lines 66 of the second group 64. As for the mooring lines 62 of the first group 60, the mooring lines 66 of the second group 64 are laid in the water, with a buoy at the first point 78. Then, the hull 30 is passed above the mooring lines 66 of the second group 64. The free ends of the mooring lines 66 are pulled to the deck 46 on the first side 38 of the longitudinal axis A-A′, advantageously by using a tensioning winch 68.
Each first link of the mooring line 66 of the second group 64 is inserted in a corresponding split pipe 124 sliding towards the underwater stopper 122.
Thereafter, the mooring lines 62 of the first group 60 are put in place, as described above for the first installation 10.
The third installation 120 according to the invention is therefore very easy to connect or disconnect with decreased risk of chain link twist compared to second installation.
A variant of the installations 10, 110, 120 disclosed above is shown in
The pipe 20 is for example a flexible riser having as shown in
The present application is a U.S. National Phase Application under 35 U.S.C. § 371 of International Patent Application No. PCT/IB2018/001405, filed Nov. 6, 2018. The entire contents of which are hereby incorporated by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2018/001405 | 11/6/2018 | WO | 00 |
