CN116714717A - Method for pre-tensioning offshore floating body mooring system on seabed - Google Patents
Method for pre-tensioning offshore floating body mooring system on seabed Download PDFInfo
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- CN116714717A CN116714717A CN202310898672.8A CN202310898672A CN116714717A CN 116714717 A CN116714717 A CN 116714717A CN 202310898672 A CN202310898672 A CN 202310898672A CN 116714717 A CN116714717 A CN 116714717A
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- 238000000034 method Methods 0.000 title claims abstract description 38
- 238000009434 installation Methods 0.000 claims abstract description 48
- 229910000831 Steel Inorganic materials 0.000 claims description 45
- 239000010959 steel Substances 0.000 claims description 45
- 238000006243 chemical reaction Methods 0.000 claims description 3
- 238000011900 installation process Methods 0.000 abstract description 2
- 230000009286 beneficial effect Effects 0.000 description 3
- 238000010276 construction Methods 0.000 description 1
- 230000008878 coupling Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
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- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/04—Fastening or guiding equipment for chains, ropes, hawsers, or the like
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/18—Stoppers for anchor chains
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/20—Adaptations of chains, ropes, hawsers, or the like, or of parts thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/20—Adaptations of chains, ropes, hawsers, or the like, or of parts thereof
- B63B2021/203—Mooring cables or ropes, hawsers, or the like; Adaptations thereof
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B21/00—Tying-up; Shifting, towing, or pushing equipment; Anchoring
- B63B21/50—Anchoring arrangements or methods for special vessels, e.g. for floating drilling platforms or dredgers
- B63B2021/505—Methods for installation or mooring of floating offshore platforms on site
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Ocean & Marine Engineering (AREA)
- Revetment (AREA)
Abstract
The invention relates to a method for pre-tensioning a marine floating body mooring system on the seabed, which belongs to the technical field of ships and ocean engineering and comprises the steps of arranging anchor piles, connecting a mooring chain and anchor end chain links on a seabed tensioner, sinking the seabed tensioner to the seabed and pre-tensioning. The method for pretensioning the offshore floating body mooring system on the seabed disclosed by the invention has the advantages of simple installation process, reduced installation requirements, effectively improved installation efficiency, reduced installation cost and realization of rapid pretensioning.
Description
Technical Field
The invention belongs to the technical field of ships and ocean engineering, and particularly relates to a method for pre-tensioning a marine floating body mooring system on the seabed.
Background
The mooring system is important equipment for positioning the offshore floating body and generally comprises an anchor, a mooring chain, a connecting assembly, a chain stopper and a tensioning device, wherein one end of the mooring chain is tied on the offshore floating body (such as a floating production platform or a floating fan), and the chain stopper is arranged on the mooring chain connected with the offshore floating body and is used for adjusting the length of the mooring chain to achieve a set tensioning force; the other end is tied on the anchor and fixed with the sea bottom. The existing pretensioning method is realized by adopting a mode of matching a crane and a chain stopper, but the method has higher requirements on a mounting ship, has high cost and great difficulty, and is not beneficial to large-scale mounting operation.
Disclosure of Invention
Aiming at the problems, the invention aims to provide a method for pretensioning an offshore floating body mooring system on the seabed, which is used for solving the problems that the existing pretensioning method has higher requirements on a mounting ship, has high cost and high difficulty and is not beneficial to large-scale mounting operation.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the invention discloses a method for pre-tensioning a marine floating body mooring system on the seabed, which comprises the following steps:
setting anchor piles: selecting a preset position on the sea floor, arranging an anchor at the preset position, tying an anchor end chain link at the end part of the anchor, connecting a steel wire rope at the free end of the anchor end chain link, and marking the top of the steel wire rope by a first buoy;
the mooring chain and anchor end links are connected to the subsea tensioner: connecting the free ends of the mooring chain and the free ends of the anchor end links to a subsea tensioner on the deck of the installation vessel;
the subsea tensioner is submerged to the sea floor: the submarine tensioners and anchor end links and mooring chains connected with the submarine tensioners are slowly lowered onto the seabed between the offshore floating body and the preset position of the anchor by installing a ship traction steel wire rope:
pretensioning is carried out: the anchor end chain links or mooring chains are towed by using the towing steel wire rope of the installation vessel, pretensioning is carried out on the whole chain to be tensioned until the expected tensioning force is reached, and the towed steel wire rope is released.
Specifically, the method for connecting the mooring chain and the anchor end chain link to the subsea tensioner is as follows:
the free end of the mooring chain is towed to a position between the offshore floating body and the anchor through the installation vessel, and the free end of the mooring chain is connected with the seabed tensioner through the connecting shackle on the deck of the installation vessel:
simultaneously, according to the mark of the first buoy, a steel wire rope connected with the anchor end chain link is pulled to a mounting ship, the steel wire rope is penetrated from the chain inlet end of the seabed tensioner, passes through the lower part of the chain stopper and penetrates out from the chain wheel side of the chain guide module:
and the connection of the free end of the mooring chain and the free end of the anchor end chain link at the seabed tensioner is completed, so that the mooring chain, the seabed tensioner and the anchor end chain link are connected into a whole chain to be tensioned.
Specifically, the method for implementing pretension is as follows:
the anchor end chain links are towed by using the installation vessel to drag the steel wire rope, the seabed tensioner is close to the anchor, the anchor end chain links connecting the seabed tensioner and the anchor are shortened, the pretension of the whole chain to be tensioned is realized, and the towed steel wire rope is released after the expected tensioning force is reached.
Preferably, the mooring chain and anchor end links are attached to the subsea tensioner by:
finding and releasing a steel wire rope tied at the free end of the anchor end chain link according to the identification of the first buoy, and connecting the free end of the anchor end chain link with a seabed tensioner through a connecting shackle on a deck of an installation ship;
simultaneously, the free end of the mooring chain penetrates through the chain inlet end of the submarine tensioner, passes through the lower part of the chain stopper and penetrates out of the chain wheel side of the chain guide module to expose the end, the exposed end is tied with a steel wire rope, and the other end of the steel wire rope is arranged on a winch of the installation vessel, so that the free end of the mooring chain is pulled by the steel wire rope;
and the connection of the free end of the mooring chain and the free end of the anchor end chain link at the seabed tensioner is completed, so that the mooring chain, the seabed tensioner and the anchor end chain link are connected into a whole chain to be tensioned.
Specifically, the method for implementing pretension is as follows:
the installation ship is used for dragging the steel wire rope to drag the mooring chain, so that the seabed tensioner is close to the offshore floating body, the mooring chain connecting the seabed tensioner and the offshore floating body is shortened, the pretension of the whole chain to be tensioned is realized, and the dragged steel wire rope is released after the expected tensioning force is reached.
Specifically, in the process of pre-tensioning the whole chain to be tensioned, once the tensioning force exceeds a set value, an ROV robot is used to submerge the chain stopper to reach the vicinity of the seabed tensioner, the chain stopper of the seabed tensioner is shifted to loosen the free end of the mooring chain or the free end of the anchor end chain link, the chain automatically falls back under the reaction of the tensioning force, the tensioning force is made to be close to or lower than the set value, the chain stopper is released to automatically lock the chain, and the pre-tensioning is repeatedly performed.
Specifically, the offshore floating body is a floating production platform or a floating fan.
Compared with the prior art, the invention has the beneficial effects that:
the invention discloses a method for pre-tensioning an offshore floating body mooring system on the seabed, which is characterized in that a mooring chain and an anchor end chain link are connected to a seabed tensioner, an installation ship is used for dragging the anchor end chain link in a direction far away from an offshore floating body or dragging the mooring chain in a direction near the offshore floating body, pre-tensioning is carried out on the whole chain to be tensioned until the expected tensioning force is reached, and the dragged steel wire rope is released, so that the pre-tensioning of the offshore floating body mooring system on the seabed is realized, the pre-tensioning difficulty is reduced, the purposes of improving the installation efficiency and reducing the installation cost are achieved, the large-scale installation operation is facilitated, and the offshore floating body mooring system has higher practical value.
Drawings
FIG. 1 is a schematic diagram of a prior art subsea tensioner;
FIG. 2 is a schematic illustration of a method of pretensioning a marine floating body mooring system at the sea floor provided by an embodiment of the invention;
figure 3 is a schematic illustration of a method of pretensioning a marine floating body mooring system at the sea floor according to another embodiment of the invention.
Reference numerals illustrate: 1-a base and 11-a boss; a 2-connection assembly; 3-tensioner, 31-main body structure, 32-chain guide module, 33-chain stopper, 34-chain inlet end; 4-reinforcing ribs; 5-sacrificial anode;
10-an offshore floating body; 20-anchor piles, 21-anchor end chain links and 22-steel wire ropes; 30-subsea tensioners; 40-installing a ship; 50-mooring chain.
Detailed Description
Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
The invention discloses a method for pre-tensioning an offshore floating body mooring system on the seabed, which adopts the existing seabed tensioner, connects the free end of a mooring chain 50 and the free end of an anchor end chain link 21 on a deck of a mounting ship 40 to the seabed tensioner 30, pulls a wire rope 22 to drag the anchor end chain link 21 or the mooring chain 50 by using the mounting ship 40, pre-tensions the whole chain to be tensioned until the expected tensioning force is reached, and releases the pulled wire rope 22. The invention does not require the use of a special mooring chain installation vessel, pulls the top and middle links onto the deck and connects to tensioners, then releases into the water and pretensions; the method for pre-tensioning the offshore floating body mooring system on the seabed disclosed by the invention is simple in installation process, reduces the installation requirement, can effectively improve the installation efficiency and reduce the installation cost, and realizes rapid pre-tensioning.
Example 1: seabed tensioner
Embodiment 1 provides a subsea tensioner, the structure of which is described in detail below with reference to the accompanying drawings.
Referring to fig. 1, the subsea tensioner comprises a base 1, a tensioner 3, a connection assembly 2, a stiffener 4 and a sacrificial anode 5.
Wherein, the base 1 is located on the seabed to play an anti-sinking role.
Specifically, base 1 sets up to the H type, and base 1 four corners symmetry is provided with boss 11, and boss 11 sets up to middle part hollow out construction, and boss 11 cross section sets up to the trapezoid.
Reinforcing ribs 4 are symmetrically arranged in the middle of two sides of the base 1.
In order to improve stability, the side surface of the base 1 is provided with a skirt.
The middle part of base 1 is provided with tensioning ware 3, and tensioning ware 3 one end is connected through coupling assembling 2 and other chain links, and the other end sets up to hollow structure and is convenient for the chain to pass.
The tensioner 3 comprises a main body structure 31, the middle part of the base 1 is provided with a bottom concave structure, and the main body structure 31 is fixed at the middle part of the base 1 through bolts.
The main body structure 31 is provided with a chain entry end 34.
The middle part of the main body structure 31 is provided with a chain guide module 32, one end of the main body structure 31 is provided with a chain stopper 33, and two sides of the main body structure 31 are symmetrically provided with a plurality of sacrificial anodes 5.
The use method of the seabed tensioner comprises the following steps:
one end of the anchor is reserved with an anchor end chain link with enough length and marked by a pontoon;
the installation vessel pulls the mooring chain all the way to a position near the anchor;
the pontoon pulls the end head of the anchor end chain link to the installation vessel, and the anchor end chain link is connected with the tensioner 3 through the connecting component 2;
the bottom end of the mooring chain is penetrated into the chain stopper 33 from the chain inlet end 34 of the tensioner 3 and penetrated out from the chain wheel side of the chain guide module 32 by the traction of the steel wire rope;
slowly lowering the tensioner 3 and chain to the seabed;
the installation ship tows the mooring chains in the opposite direction through the steel wire rope, and pretensions the whole mooring chains;
the chain stopper 33 is connected with a spring, has unidirectional automatic locking capability, and the chain stopper 33 completely bears the tension of the anchor leg after locking.
Among them, the subsea tensioner is the prior art, and more structural details are found in chinese patent application No. 202211157055.4, a mooring tensioner near the anchor end.
Example 2: marine floating body mooring system
Embodiment 2 provides an offshore floating body mooring system, the structure of which is described in detail below with reference to the accompanying drawings.
The offshore floating body mooring system comprises an offshore floating body 10, anchors 20, a subsea tensioner 30, a mounting vessel 40, a mooring chain 50,
the anchor 20 is fixed to the sea floor, and anchor end links 21 are tied to the ends of the anchor 20.
Specifically, the anchor 2 may be a pile anchor, or may be a suction anchor, a gravity anchor, or the like.
The subsea tensioner 30 employs the subsea tensioner of embodiment 1, and the subsea tensioner connection assembly 2 of embodiment 1 is a connection shackle.
The fixed end of the mooring chain 50 is tied to the offshore floating body 10, the free end is fixed to the subsea tensioner 30, the free end of the anchor end link 21 is fixed to the subsea tensioner 30, whereby the mooring chain 50, the subsea tensioner 30, the anchor end link 21 are connected to one whole chain to be tensioned, connecting the offshore floating body 10 with the anchor 20.
The connection of the free ends of the mooring chain 50 and the free ends of the anchor end links 21, respectively, with the sea floor tensioners 30 is performed on the deck of the installation vessel 40 until after the connection of the free ends of the mooring chain 50 and the free ends of the anchor end links 21 at the sea floor tensioners 30 is completed, the sea floor tensioners 30 sink to the sea floor and are located between the offshore floating body 10 and the anchors 20, the installation vessel 40 pulls the free ends of the mooring chain 50 or the free ends of the anchor end links 21 through the steel ropes 22 to effect the tensioning of the whole chain to be tensioned.
There are two ways in which the free ends of the mooring chain 50 and the free ends of the anchor end links 21 are connected to the subsea tensioner 30:
the first way is: the free end of the mooring chain 50 is connected to the subsea tensioner 30 by a connection shackle, the free end of the anchor end link 21 penetrating from the chain entry end 34 of the subsea tensioner 30, passing under the chain stopper 33 and out the sprocket side of the chain guide module 32, exposing the end, which is pulled by the wire rope 22;
correspondingly, the method for realizing the tensioning of the whole chain to be tensioned is as follows:
the anchor chain links 21 are towed by the installation vessel 40 towing the wire ropes 22, the subsea tensioners 30 are brought close to the anchors 20, the anchor chain links 21 connecting the subsea tensioners 30 with the anchors 20 are shortened, a pretensioning of the whole chain to be tensioned is achieved, and the towed wire ropes 22 are released after the desired tensioning force has been reached, as shown in fig. 2.
The second way is: the steel wire rope 22 tied at the free end of the anchor end chain link 21 is found and released according to the identification of the first buoy, the free end of the anchor end chain link 21 is connected with the seabed tensioner 30 through a connecting shackle, the free end of the mooring chain 50 penetrates from the chain inlet end 34 of the seabed tensioner 30, passes through the lower part of the chain stopper 33 and penetrates out from the chain wheel side of the chain guide module 32 to expose the end, the exposed end is tied with the steel wire rope 22, and the other end of the steel wire rope 22 is arranged on a winch of the installation vessel 40, so that the free end of the mooring chain 50 is pulled by the steel wire rope 22;
correspondingly, the method for realizing the tensioning of the whole chain to be tensioned is as follows:
the installation vessel 40 is used to pull the steel wire rope 22 to drag the mooring chain 50, the subsea tensioner 30 is brought close to the offshore floating body 10, the mooring chain 50 connecting the subsea tensioner 30 and the offshore floating body 10 is shortened, pretensioning of the whole chain to be tensioned is achieved, and the pulled steel wire rope 22 is released after the desired tensioning force is reached, as shown in fig. 3.
In particular, the offshore floating body 10 is on a floating production platform or a floating wind turbine.
Example 3: method for pre-tensioning offshore floating body mooring system on seabed
Embodiment 3 provides a method of pretensioning an offshore floating body mooring system on the seafloor, employing the offshore floating body mooring system of embodiment 2, comprising the steps of:
step one: arrangement of anchor piles
At the seabed a predetermined position is selected, at which position an anchor 20 is arranged, the end of the anchor 20 is tied with an anchor end link 21, the free end of the anchor end link 21 is connected to the buoy via a wire line 22 and is identified by a first buoy.
The "floating body" to which the wire rope 22 is connected may be the above-mentioned offshore floating body 10, or other floating bodies floating on the sea surface.
Step two: connection of mooring chain and anchor end links to a subsea tensioner
On the deck of the installation vessel 40, the free ends of the mooring chains 50 and the free ends of the anchor end links 21 are connected to the subsea tensioners 30, specifically including two implementations.
In a first form, the free end of the mooring chain 50 is towed by the installation vessel 40 to a position between the offshore buoy 10 and the anchor 20, and the free end of the mooring chain 50 is connected to the subsea tensioner 30 by a connection shackle: at the same time, according to the identity of the first buoy, the wire rope 22 connected to the anchor end link 21 is pulled onto the installation vessel 40, the wire rope 22 is threaded from the chain entry end 34 of the subsea tensioner 30, through under the chain stopper 33 and out the sprocket side of the chain guide module 32: the connection of the free end of the mooring chain 50 and the free end of the anchor end chain link 21 at the subsea tensioner 30 is completed, such that the mooring chain 50, the subsea tensioner 30, the anchor end chain link 21 are connected into one whole chain to be tensioned.
In the second form, the wire rope 22 tied at the free end of the anchor end link 21 is found and released according to the identification of the first buoy, and the free end of the anchor end link 21 is connected with the seabed tensioner 30 through the connection shackle; simultaneously, the free end of the mooring chain 50 penetrates from the chain inlet end 34 of the seabed tensioner 30, passes under the chain stopper 33 and penetrates from the chain wheel side of the chain guide module 32 to expose the end, the exposed end is tied with the steel wire rope 22, and the other end of the steel wire rope 22 is arranged on a winch of the installation vessel 40, so that the free end of the mooring chain 50 is pulled by the steel wire rope 22; the connection of the free end of the mooring chain 50 and the free end of the anchor end chain link 21 at the subsea tensioner 30 is completed, such that the mooring chain 50, the subsea tensioner 30, the anchor end chain link 21 are connected into one whole chain to be tensioned.
Wherein one end of the mooring chain 50 is tied to the offshore floating body 10 to form a fixed end and the other end is a free end.
Step three: the subsea tensioner 30 is submerged to the sea floor
The subsea tensioner 30, with the anchor end links 21 connected thereto, the mooring chain 50 is slowly lowered onto the seabed at a position between the offshore buoy 10 and the predetermined position of the anchor 20 by pulling the steel line 22 by the installation vessel 40.
Specifically, the traction of the wire rope 22 by the installation vessel 40 includes two implementations:
in the first form, the installation vessel 40 is provided with a winch, the winch is provided with a threading wheel, the wire rope 22 is wound on the threading wheel of the winch, and the winch of the installation vessel 40 is rotated to drive the wire rope 22 to be released and recovered, so that the wire rope 22 is pulled.
In the second form, to keep the subsea tensioner 30 stable against rollover, a winch or crane may be used to connect a large loop with an ROV-operable hook, first four separate pre-configured lifting lugs of the subsea tensioner 30, and 4 pre-configured steel wire ropes on the large loop are threaded onto the four lifting lugs of the subsea tensioner 30, then the subsea tensioner 30 is placed on the seabed, but this solution eventually requires opening the ROV hook by an ROV robot, releasing the steel wire ropes 22 to complete the installation.
Step four: implementing pretensioning
Pulling the wire rope 22 with the installation vessel 40 tows the anchor end links 21 or mooring chains 50, effecting pretensioning of the whole chain to be tensioned, until the desired tensioning force is reached, after which the towed wire rope 22 is released.
In particular, when the connection of the mooring chain 50 and the anchor end links 21 to the subsea tensioner 30 is of a first form, the corresponding method of performing the pretensioning is: the anchor end links 21 are towed by the installation vessel 40 towing the wire rope 22, the subsea tensioner 30 is brought close to the anchor 20, the anchor end links 21 connecting the subsea tensioner 30 and the anchor 20 are shortened, a pretensioning of the whole chain to be tensioned is achieved, and the towed wire rope 22 is released after the desired tensioning force has been reached.
When the connection of the mooring chain 50 and the anchor end links 21 to the subsea tensioner 30 is of the second type, the corresponding method of performing the pretensioning is: the installation vessel 40 is used to pull the steel wire rope 22 to drag the mooring chain 50, the seabed tensioner 30 is made to approach the offshore floating body 10, the mooring chain 50 connecting the seabed tensioner 30 and the offshore floating body 10 is shortened, the pretensioning of the whole chain to be tensioned is achieved, and the pulled steel wire rope 22 is released after the expected tensioning force is reached.
In the pre-tensioning of the whole chain to be tensioned, once the tensioning force exceeds a set value, the ROV robot is used to submerge near the seabed tensioner 30, the chain stopper 33 of the seabed tensioner 30 is shifted to loosen the free end of the mooring chain 50 or the free end of the anchor end chain link 21, the chain automatically falls back under the reaction of the tensioning force, the tensioning force is close to or lower than the set value, the chain stopper 33 is released to automatically lock the chain, and the pre-tensioning is repeated.
In particular, the offshore floating body 10 is on a floating production platform or a floating wind turbine.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims (7)
1. A method of pre-tensioning an offshore floating body mooring system at the seafloor, comprising:
setting anchor piles: an anchor (20) is arranged at a preset position on the sea floor, an anchor end chain link (21) is tied at the end part of the anchor (20), a steel wire rope (22) is connected with the free end of the anchor end chain link (21), and a first buoy is used for marking the top of the steel wire rope (22);
the mooring chain and anchor end links are connected to the subsea tensioner: on the deck of the installation vessel (40), connecting the free ends of the mooring chain (50) and the free ends of the anchor end links (21) to the subsea tensioner (30);
the subsea tensioner is submerged to the sea floor: the submarine tensioners (30) and the anchor end links (21) and the mooring chains (50) connected with the submarine tensioners are slowly lowered onto the seabed between the offshore floating body (10) and the preset position of the anchor (20) by the installation vessel (40) pulling the steel wire rope:
pretensioning is carried out: the anchor chain links (21) or mooring chains (50) are towed by the installation vessel (40) towing the wire ropes (22), pretensioning is applied to the whole chain to be tensioned until the desired tensioning force is reached, and the towed wire ropes (22) are released.
2. Method for pretensioning an offshore floating body mooring system on the sea floor according to claim 1, characterized in that,
the method for connecting the mooring chain and the anchor end chain link to the seabed tensioner comprises the following steps:
the free end of the mooring chain (50) is towed to a position between the offshore floating body (10) and the anchor (20) by the installation vessel (40), and the free end of the mooring chain (50) is connected with the seabed tensioner (30) by a connecting shackle on the deck of the installation vessel (40):
simultaneously, according to the identification of the first buoy, the steel wire rope (22) connected with the anchor end chain link (21) is pulled to the installation vessel (40), the steel wire rope (22) is penetrated from the chain inlet end (34) of the seabed tensioner (30), passes under the chain stopper (33) and penetrates out from the chain wheel side of the chain guide module (32):
the connection of the free end of the mooring chain (50) and the free end of the anchor end chain link (21) at the seabed tensioner (30) is completed, so that the mooring chain (50), the seabed tensioner (30) and the anchor end chain link (21) are connected into a whole chain to be tensioned.
3. A method of pretensioning an offshore floating body mooring system in the sea floor according to claim 2, characterized in that the method of performing pretensioning is:
the anchor end chain links (21) are towed by a mounting vessel (40) through the use of a towing wire rope (22), the seabed tensioners (30) are brought close to the anchors (20), the anchor end chain links (21) connecting the seabed tensioners (30) and the anchors (20) are shortened, pretensioning of the whole chain to be tensioned is achieved, and the towed wire rope (22) is released after the desired tensioning force is reached.
4. Method for pretensioning an offshore floating body mooring system on the sea floor according to claim 1, characterized in that,
the method for connecting the mooring chain and the anchor end chain link to the seabed tensioner comprises the following steps:
finding and releasing a steel wire rope (22) tied at the free end of the anchor end chain link (21) according to the identification of the first buoy, and connecting the free end of the anchor end chain link (21) with a seabed tensioner (30) through a connecting shackle on the deck of the installation vessel (40);
simultaneously, the free end of the mooring chain (50) penetrates from the chain inlet end (34) of the submarine tensioner (30), passes under the chain stopper (33) and penetrates from the chain wheel side of the chain guide module (32) to expose the end, the exposed end is tied with the steel wire rope (22), and the other end of the steel wire rope (22) is arranged on a winch of the installation vessel (40) so that the free end of the mooring chain (50) is pulled by the steel wire rope (22);
the connection of the free end of the mooring chain (50) and the free end of the anchor end chain link (21) at the seabed tensioner (30) is completed, so that the mooring chain (50), the seabed tensioner (30) and the anchor end chain link (21) are connected into a whole chain to be tensioned.
5. The method of pretensioning an offshore floating body mooring system in the sea floor according to claim 4, wherein the method of performing pretensioning is:
the installation vessel (40) is used for towing the steel wire rope (22) to tow the mooring chain (50), the seabed tensioner (30) is close to the offshore floating body (10), the mooring chain (50) connecting the seabed tensioner (30) and the offshore floating body (10) is shortened, pretensioning of the whole chain to be tensioned is achieved, and the towed steel wire rope (22) is released after the expected tensioning force is reached.
6. Method for pretensioning an offshore floating body mooring system on the sea floor according to claim 1, characterized in that,
in the process of pre-tensioning the whole chain to be tensioned, once the tensioning force exceeds a set value, an ROV robot is used for submerging to the vicinity of the seabed tensioner (30), the chain stopper (33) of the seabed tensioner (30) is shifted to loosen the free end of the mooring chain (50) or the free end of the anchor end chain link (21), the chain automatically falls back under the reaction of the tensioning force, the tensioning force is close to or lower than the set value, the chain stopper (33) is released to automatically lock the chain, and the pre-tensioning is repeatedly performed.
7. Method for pretensioning an offshore floating body mooring system on the sea floor according to claim 1, characterized in that,
the offshore floating body (10) is a floating production platform or a floating fan.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117284935A (en) * | 2023-09-19 | 2023-12-26 | 华东送变电工程有限公司 | Remote control device of split type hydraulic grinding system and control method thereof |
| CN117702795A (en) * | 2023-12-14 | 2024-03-15 | 江苏科技大学 | Pile foundation capable of preventing anchor chain from being stretched and seabed groove from being formed and implementation method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117284935A (en) * | 2023-09-19 | 2023-12-26 | 华东送变电工程有限公司 | Remote control device of split type hydraulic grinding system and control method thereof |
| CN117702795A (en) * | 2023-12-14 | 2024-03-15 | 江苏科技大学 | Pile foundation capable of preventing anchor chain from being stretched and seabed groove from being formed and implementation method thereof |
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