CN114198569A

CN114198569A - Underwater connection method of dynamic flexible pipe cable and anchoring base

Info

Publication number: CN114198569A
Application number: CN202111516165.0A
Authority: CN
Inventors: 齐金龙; 段立志; 石锦坤; 周健伟; 高超; 李国毅; 马庆林; 刘耀江; 陈晓东; 张云鹏; 梁光强; 张凯
Original assignee: COOEC Subsea Technology Co Ltd
Current assignee: COOEC Subsea Technology Co Ltd
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2022-03-18
Anticipated expiration: 2041-12-06
Also published as: CN114198569B

Abstract

The invention discloses an underwater connection method of a dynamic flexible pipe cable and an anchoring base, which comprises the following steps: s1, connecting the permanent anchor rigging and the suspension rigging to the attachment element of the dynamic flexible umbilical; s2, laying the dynamic flexible pipe cable under water until the pipe section with the attachment element enters water, and suspending a first temporary counterweight connected with a suspension rigging below the attachment element through the action of gravity; s3, continuing to lower the dynamic flexible pipe cable until the first temporary counterweight is lowered on the seabed near the anchoring base; s4, the ship crane puts the second temporary counterweight down into the water to be close to the attachment element, the second temporary counterweight is hung on the attachment element, and the attachment element is pulled down to be close to the anchoring base under the action of gravity; s5, connecting the permanent anchor rigging to the anchor base at the tie-down point. The underwater connection method of the dynamic flexible pipe cable and the anchoring base is simple, safe and reliable, and solves the operation problem that the dynamic pipe cable with positive buoyancy is connected to the anchoring base on the seabed.

Description

Underwater connection method of dynamic flexible pipe cable and anchoring base

Technical Field

The invention relates to the technical field of underwater pipe cable installation, in particular to an underwater connection method of a dynamic flexible pipe cable and an anchoring base.

Background

In the development of deepwater offshore oil, dynamic flexible umbilical means oil and gas pipelines, cables and umbilicals connecting subsea umbilical terminals and floating facilities (such as FPSO) on the sea surface. The wave configuration is one of the commonly used configurations for dynamic flexible umbilicals. The wave configuration is that a floating body material is arranged on a dynamic pipe cable between a mud point on the sea bottom and a floating facility on the sea surface, the dynamic pipe cable close to one end of the mud point is lifted to form an upward bending section in water, and the dynamic pipe cable between the upward bending section and the top forms a downward bending section through a counterweight material or the dead weight of the pipe cable. Whether the dynamic tube cable has an anchoring wave configuration near a mud point is divided into two forms of anchoring and non-anchoring. The dynamic pipe cable with anchored wave structure has one anchoring cable to anchor the dynamic pipe cable to the anchoring base on the seabed near the mud depositing point of the dynamic pipe cable. Therefore, in order to connect the dynamic tube cable to the anchoring base with the anchored wave-shaped dynamic tube cable, the dynamic tube cable needs to be pulled down against the buoyancy of the upward bent section of the dynamic tube cable, so that the anchoring connection element of the dynamic tube cable and the anchoring base are close to each other, and then the permanent anchoring rigging between the fastening point of the dynamic tube cable and the anchoring base is connected.

For the connection between the permanent anchor rigging and the anchor base of the dynamic umbilical, the currently used method is: and arranging a winch on the laying ship, performing route steering on a steel wire rope of the winch through the seabed, connecting the steel wire rope to a dynamic pipe cable anchoring point, and finishing the connection of the permanent anchoring rigging in a mode that the winch pulls down the dynamic pipe cable anchoring point. However, the method is difficult to realize due to the arrangement of the route steering of the winch steel wire rope, the existing of the winch steel wire rope limits the heading of the laying ship and the like, the laying operation is influenced, and the applicability is poor.

Disclosure of Invention

The invention aims to provide an underwater connection method of a dynamic flexible pipe cable and an anchoring base.

The technical scheme adopted by the invention for solving the technical problems is as follows: the underwater connection method of the dynamic flexible pipe cable and the anchoring base comprises the following steps:

s1, connecting the permanent anchor rigging and the suspension rigging to the attachment element of the dynamic flexible umbilical;

s2, laying the dynamic flexible pipe cable under water until the pipe section with the attachment element enters water, and suspending a first temporary counterweight connected with the suspension rigging below the attachment element through gravity;

s3, continuing to lower the dynamic flexible pipe cable until the first temporary counterweight is lowered on the seabed near the anchoring base, and temporarily anchoring the dynamic flexible pipe cable;

s4, the ship crane puts a second temporary counterweight into water to be close to the attachment element, the second temporary counterweight is hung on the attachment element, and the second temporary counterweight pulls the attachment element to be close to the anchoring base through the action of gravity;

s5, connecting one end of the permanent anchor rigging remote from the attachment element to a mooring point of the anchor base, completing the subsea connection of the dynamic flexible umbilical to the anchor base.

Preferably, in step S1, one end of a permanent anchoring rigging is connected to the attachment element of the dynamic flexible umbilical on the laying vessel; temporarily fixing the permanent anchor rigging axially to the dynamic flexible umbilical;

in step S5, the temporary fixation of the permanent anchor rigging on the dynamic flexible umbilical is released, the permanent anchor rigging is pulled apart, and the end of the permanent anchor rigging remote from the attachment element is connected to the mooring point of the anchor base by the ROV.

Preferably, in step S1, one end of the suspension rigging is connected to the attachment element, and the suspension rigging is folded and temporarily fixed on the attachment element;

in step S2, after the pipe section with the attachment element is filled with water, the first temporary counterweight is suspended in the water by a ship crane; connecting the other end of the suspension rigging to the first temporary counterweight under water, and disconnecting the vessel crane from the first temporary counterweight.

Preferably, in step S1, one end of the suspension rigging is first connected to the attachment element, and the other end of the suspension rigging is connected to the first temporary weight;

step S2 further includes: and putting the first temporary counterweight into water.

Preferably, in step S2, the portion of the dynamically flexible umbilical above the attachment element is buoyant and the first temporary weight pulls the portion of the dynamically flexible umbilical above the attachment element away from the hull structure under the influence of gravity.

Preferably, in step S3, along with the lowering depth of the dynamic flexible pipe cable, a third temporary counterweight is lowered into the water and connected in series with the first temporary counterweight, so as to counteract the buoyancy caused by the float on the dynamic flexible pipe cable, so that the dynamic flexible pipe cable is always far away from the hull structure during the lowering process.

Preferably, in step S1, a branch rigging is connected to the suspension rigging;

in step S4, after the second temporary counterweight is lowered to the vicinity of the attachment element, connecting the second temporary counterweight to the branch rigging by an ROV so that the second temporary counterweight is suspended on the attachment element; the vessel crane continues lowering the second temporary counterweight to pull down the attachment element until the distance between the attachment element and the anchoring base is less than the length of the permanent anchoring rigging.

Preferably, the second temporary weight is landed on the seabed or suspended below the attachment element when the distance between the attachment element and the anchoring base is less than the length of the permanent anchoring rigging.

Preferably, the underwater connection method of the dynamic flexible pipe cable and the anchoring base further comprises the following steps:

and S6, recovering the first temporary counterweight and the second temporary counterweight.

Preferably, step S6 includes:

s6.1, lifting the second temporary counterweight to the state that the rigging between the second temporary counterweight and the attachment element is loosened by the ship crane, and unlocking the rigging by an ROV;

s6.2, the ship crane continuously lifts and recovers the second temporary counterweight to a ship;

s6.3, the ship crane continues to lower the hook into water, the connection between the suspension rigging and the attachment element is released through the ROV, and after the first temporary counterweight is connected with the hook, the first temporary counterweight is lifted and recovered to a ship.

The underwater connection method of the dynamic flexible pipe cable and the anchoring base has the advantages that the temporary counter weight is hung on the dynamic flexible pipe cable to assist the connection of the permanent anchoring rigging and the anchoring base on the seabed, the operation is simple, safe and reliable, and the operation problem that the dynamic flexible pipe cable with positive buoyancy is connected to the anchoring base on the seabed is solved.

Drawings

The invention will be further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic illustration of the process of the present invention for connecting a permanent anchor rigging to an anchor base by an ROV;

fig. 2 is a schematic illustration of the present invention after the permanent anchor rigging has been attached to the anchor base.

Detailed Description

For a more clear understanding of the technical features, objects and effects of the present invention, embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

The underwater connection method of the dynamic flexible pipe cable and the anchoring base is mainly applied to the laying process of the dynamic flexible pipe cable, and the dynamic flexible pipe cable and the anchoring base are connected underwater. When the dynamic flexible pipe cable is laid, one end of the dynamic flexible pipe cable is connected with a submarine pipe cable terminal, then the dynamic flexible pipe cable is laid on the seabed along a route, finally the dynamic flexible pipe cable is connected to an anchoring base of the seabed through a permanent anchoring rigging, and the other end of the dynamic flexible pipe cable is connected with a sea surface floating facility (such as FPSO), so that the whole dynamic flexible pipe cable is laid.

Referring to fig. 1 and 2, a method for connecting a dynamic flexible pipe string to an anchoring base underwater according to an embodiment of the present invention may include the following steps:

s1, connecting the permanent anchor rigging 30 and the suspension rigging 40 to the attachment element 20 of the dynamic flexible umbilicus 10, respectively.

The suspension rigging 40 is used for the attachment of a first temporary weight 50.

In this step, on the laying vessel, the corresponding anchoring position on the dynamic flexible umbilical 10 is determined based on the position of the anchoring base 100 on the seabed, and the attachment element (structure such as an anchoring clip) 20 is installed at the anchoring position. Further, one end of the permanent anchoring rigging 30 is connected with the attachment element 20.

Considering that the permanent anchor rigging 30 has a certain length and avoids floating underwater or winding with the dynamic flexible pipe cable 10, the permanent anchor rigging 30 may be temporarily fixed to the dynamic flexible pipe cable 10 by a binding band or the like along the axial direction of the dynamic flexible pipe cable 10; the permanent anchor rigging 30 can then be deployed by subsequently pulling the tie-up strap apart by the ROV.

Wherein one end of the suspension rigging 40 can be connected to the attachment element 20 on the laying vessel in advance. After the subsequent attachment element 20 is submerged, the first temporary weight 50 is again connected underwater to the suspension rigging 40. Alternatively, on the laying vessel, one end of the suspension rigging 40 is connected to the attachment element 20 and the other end is connected to the first temporary counterweight 50 by means of a connection rigging 51.

In addition, in order to facilitate the connection of the subsequent second temporary weights 60, the branch rigging 41 is connected to the suspension rigging 40 in advance.

S2, the dynamic flexible umbilical 10 is laid underwater until the pipe section with the attachment element 20 is submerged, and the first temporary weight 50 is suspended below the attachment element 20 by gravity.

Wherein, after the above steps are completed to connect the permanent anchoring rigging 30, the dynamic flexible pipe cable 10 is continuously lowered on the laying vessel, the pipe section with the attachment element 20 is also submerged, the subsequent pipe section (the dynamic flexible pipe cable part above the attachment element 20) of the dynamic flexible pipe cable 10 is also continuously submerged and is provided with a floater (floater block), and the pipe section in which the floater floats in the water under the buoyancy of the floater.

When the first temporary weight 50 is connected under water, after the pipe section with the attachment element 20 is submerged to a certain depth (for example, but not limited to, a water depth of 80 m), the first temporary weight 50 is then hoisted into the water by the vessel crane 300. Under water, the other end of the suspension rigging 40, which is remote from the attachment element 20, is connected to the first temporary counterweight 50, and then the connection of the vessel crane 300 with the first temporary counterweight 50 is released. The first temporary counterweight 50 is connected to the suspension rigging 40 primarily by a connection rigging 51 thereon. And, in order to facilitate the connection of the ROV200 while being grabbed underwater, a hericium punch is installed at the connection end of the connection rigging 51 and the suspension rigging 40.

When the first temporary weight 50 has been connected to the suspension rigging 40 by the connection rigging 51 on the laying vessel, the first temporary weight 50 is also lowered into the water when the dynamic flexible umbilical 10 is laid under water until the pipe section with the attachment element 20 is launched into the water.

The first temporary counterweight 50 is suspended below the attachment element 20 by the connecting rigging 51 and the suspension rigging 40, and has a pull-down effect on the pipe section where the attachment element 20 is located under the action of gravity, so as to pull down the dynamic flexible pipe cable 10 against the buoyancy of the upward bent section of the dynamic flexible pipe cable (the pipe section where the float is located) behind the attachment element 20, and pull down the upward bent section of the dynamic flexible pipe cable to be close to the vertical state, so as to be away from the hull structure, and avoid collision with the hull structure.

S3, continuing to lower the dynamic flexible umbilical 10 until the first temporary weight 50 is lowered onto the seabed adjacent the anchor base 100, temporarily anchoring the dynamic flexible umbilical 10.

The first temporary counterweight 50 is arranged based on buoyancy consumed by a floater when the dynamic flexible pipe cable 10 is lowered and the buoyancy caused by the floater on the dynamic flexible pipe cable, so that the first temporary counterweight 50 can sufficiently pull down the dynamic flexible pipe cable 10 under the action of gravity to avoid collision with a hull structure, and meanwhile, along with lowering of the dynamic flexible pipe cable 10 and laying on a seabed, the first temporary counterweight 50 can be located on the seabed near the anchoring base 100.

With the first temporary weight 50 positioned on the seabed, the dynamic flexible umbilical 10 connected thereto is positioned underwater, also positioning the attachment element 20 above the anchoring base.

As for the landing position of the first temporary weight 50, the first temporary weight 50 can be laid down and lowered onto the seabed near the anchor base 100 by controlling the ship position or controlling the direction and position of the first temporary weight 50 by a ship crane operation.

Additionally, on the laying vessel, the dynamic flexible conduit 10 is lowered into the water behind tensioners that provide a clamping force to clamp the dynamic flexible conduit 10. When the tensioner provides a clamping force large enough to bear the first temporary weight 50 suspended by the dynamic flexible umbilical 10, but the weight of the first temporary weight 50 is not enough to counteract the buoyancy of the float in the subsequent laying to control the dynamic flexible umbilical 10 to be plumb without colliding with the hull structure, the tensioner can wait until the dynamic flexible umbilical 10 is lowered deeper, and when more floats are installed, one or more third temporary weights 70 are lowered into the water and connected in series with the first temporary weight 50 to counteract the buoyancy caused by the float on the dynamic flexible umbilical 10, so that the dynamic flexible umbilical 10 is kept plumb or nearly plumb to be far away from the hull structure all the time during the lowering process, and the clamping force of the tensioner is not allowed to exceed the allowable value of the dynamic flexible umbilical 10. To the third temporary counter weight 70 that needs two or more, the third temporary counter weight 70 is transferred in proper order and is connected gradually, forms series connection structure with first temporary counter weight 50 to guarantee that counter weight satisfies the requirement of dynamic flexible pipe cable design requirement and the requirement of laying equipment ability. And when the temporary balance weight is lowered to the seabed, the operation is also performed in sequence.

S4, the boat crane 300 lowers the second temporary weight 60 into the water to the vicinity of the attachment member 20, hangs the second temporary weight 60 on the attachment member 20, and the second temporary weight 60 pulls the attachment member 20 down by gravity to be close to the anchor base 100.

Before the second temporary counter weight 60 is lowered, a tail rope is connected. When the ship crane 300 lifts the second temporary counterweight 60 and puts it into water, the worker can restrict the second temporary counterweight 60 from shaking by pulling the tail rope; the tail rope is withdrawn after the second temporary weight 60 is submerged.

When the vessel crane 300 lowers the second temporary counterweight 60 to a depth close to the attachment element 20, the vessel crane 300 starts the heave compensation mode. In the heave compensation mode, the vessel crane 300 continues the lowering of the second temporary counterweight 60.

Under water, after the second temporary counterweight 60 is lowered to the vicinity of the attachment element 20, the second temporary counterweight 60 is connected by the ROV200 with the branch rigging 41 on the suspension rigging 40, so that the second temporary counterweight 60 is suspended on the attachment element 20. The vessel crane 300 continues to lower the second temporary weight 60 until it pulls the attachment element 20 down by gravity until the distance between the attachment element 20 and the anchoring base 100 is less than the length of the permanent anchoring rigging 30.

The second temporary weights 60 are connected to the branch rigging 41 primarily by means of connecting rigging 61 thereon. In addition, in order to facilitate the connection of the ROV200 by grabbing under water, a monkey head is installed at the connecting end of the connecting rigging 61.

After the connection rigging 61 of the second temporary weight 60 is connected to the suspension rigging 40 by the branch rigging 41, its length lowered on the attachment element 20 is smaller than that of the first temporary weight 50 lowered on the attachment element 20, whereby the connection of the dynamic flexible umbilical 10 to the anchor base 100 can be completed by the second temporary weight 60 pulling down the attachment element 20.

The second temporary weight 60 pulls down the attachment element 20 by gravity, so that its distance from the anchoring base 100 is less than the length of the permanent anchoring rigging 30. When the distance between the attachment element 20 and the anchoring base 100 is less than the length of the permanent anchoring rigging 30, the second temporary weight 60 can be either landed on the seabed or suspended below the attachment element 20, depending mainly on the weight of the second temporary weight 60 and the length of the rigging 61 connected thereto.

S5, connecting the end of the permanent anchor rigging 30 remote from the attachment element 20 to the mooring point of the anchor base 100, completing the underwater connection of the dynamic flexible umbilical 10 to the anchor base 100, the completed connection being shown in fig. 2.

Specifically, the temporary fixation of the permanent anchor rigging 30 on the dynamic flexible umbilical 10 may be first released by the ROV200, the permanent anchor rigging 30 is pulled apart, and then an end of the permanent anchor rigging 30 remote from the attachment element 20 is connected (e.g., hitched) to a tie point of the anchor base 100 by the ROV 200.

S6, recovering the first temporary weight 50 and the second temporary weight 60.

In one embodiment, the step S6 may further include:

s6.1, when the vessel crane 300 lifts the second temporary counterweight 60 to slacken the rigging (including the connecting rigging 61, the branch rigging 41 and the suspension rigging 40) between the second temporary counterweight 60 and the attachment element 20, the rigging is released by the ROV 200. Specifically, the connection of the connection rigging 61 and the branch rigging 41 is released.

S6.2, the vessel crane 300 continues to lift and retrieve the second temporary counterweight 60 onto the vessel, thereby retrieving the second temporary counterweight 60 and its connected connecting rigging 61 together onto the vessel.

S6.3, the vessel crane 300 continues lowering the hook into the water, disconnecting the suspension rigging 40 from the attachment element 20 by the ROV200, and after connecting the first temporary counterweight 50 with the hook, lifting and retrieving the first temporary counterweight 50 onto the vessel.

Structurally, the middle of the suspension rigging 40 is configured to allow the ROV200 to connect to a disconnected suspension member (such as a long-handled ROV hook or ROV shackle); to which the branch rigging 41 is connected. When ROV200 disconnects suspension rigging 40 from attachment element 20, the suspension components of suspension rigging 40 are primarily disconnected, thereby disconnecting suspension rigging 40; the lower part of the suspension rigging (the part below the suspension element) remains connected to the connection rigging 51 and can be retrieved to the vessel together with the connection rigging 51, the first temporary counterweight 50. The rigging part of the upper part of the suspension rigging is connected with the attachment element 20 by a shackle, which rigging part can be extracted for recovery after the suspension member is disconnected; in the event that the attachment element 20 connection point is limited in space, not facilitating the ROV200 to remove a shackle connected to the attachment element 20, the shackle may be left on the attachment element 20 if permitted.

The invention is further illustrated below by way of a dynamic riser vertical lay as an example.

The dynamic riser begins to be laid with the underwater end as a first end, the laying of the ship is suspended when the anchoring point position of the dynamic riser reaches the position above the ship moon pool cover, and the anchoring clamp (namely an attachment element) of the dynamic riser is installed at the anchoring point position. And a section of suspension rigging (including branch rigging) is respectively connected to the lifting lugs on the two sides of the anchoring clamp and temporarily fixed. White paint is coated on the suspension riggings on one side and the lifting rings at the tail ends of the branch riggings to distinguish the suspension riggings on the left side and the right side, and the permanent anchoring rigging is connected to the middle lifting lug of the anchoring clamp and is temporarily fixed.

The laying of the dynamic risers is continued and one hoisting rigging and two connecting rigging of the temporary counterweight are prepared in advance on the deck of the laying vessel. The hoisting rigging must be long enough to ensure that the crane wire rope does not interfere with the ship's side when the ship crane on the ship's side transfers the temporary counterweight to the dynamic riser anchor clamp located in the ship. The connecting rigging needs to be bound into a group and temporarily fixed on the temporary balance weight. The long handle ROV hook attached to one end of the rigging is marked with white paint to distinguish the left and right side rigging.

The anchor clamp is laid to the designed depth, the ship is suspended, the ship crane lifts the first temporary counterweight to be launched to the depth where the anchor clamp is located, the ship crane starts a heave compensation mode, the ROV pulls off the temporary fixation of the connecting rigging on the anchor clamp and the first temporary counterweight, and the connecting rigging is connected with the anchor clamp. The ship crane transfers the first temporary counter weight, the weight of the first temporary counter weight is transferred to the anchoring clamp, the ROV unlocks the hoisting rigging of the first temporary counter weight, the ROV is connected to the hoisting rigging in a folding mode on a lifting hook of the ship crane, the hoisting rigging is shortened in two modes, and therefore the whole hoisting rigging can be directly hoisted to a ship deck within the range of the hoisting capacity of the ship crane.

And continuously laying the dynamic stand pipe, enabling the anchoring card on the dynamic stand pipe to reach the design depth, suspending a third temporary counterweight to the bottom of the first temporary counterweight according to the steps, and connecting the two temporary counterweights in series.

And continuously laying the dynamic riser, and sequentially dropping the third temporary counter weight and the first temporary counter weight on the seabed, so that the horizontal distance (layback) between the laying ship and the mud landing point of the dynamic riser can be properly increased to ensure that the temporary counter weight is closer to the anchoring base of the dynamic riser when the temporary counter weight is dropped on the seabed. The dynamic riser laying continues until the transfer of the dynamic riser to the FPSO tanker and the pulling of the dynamic riser into position on the tanker turret is completed. The dynamic riser forms a wave configuration in water, the temporary counter weight forms a gravity base on the seabed, and an upward bending section with positive buoyancy of the dynamic riser at the upper part of the anchoring clamp is temporarily anchored near the anchoring base through a suspension rigging of the anchoring clamp connecting the temporary counter weight and the dynamic riser.

The laying vessel comes above the dynamic riser anchoring base and to the side of the dynamic riser by a distance of about 50 meters and cannot go directly above the anchoring base to prevent a risk of falling objects. Connecting the attachment rigging to the lifting point of the second temporary counterweight at the deck and tying the attachment rigging into a mass temporarily secured to the second temporary counterweight. And a hoisting rigging is connected between the hook head of the crane and the second temporary counterweight hoisting point. The total length of the connecting rigging of the second temporary counterweight is controlled to be shorter than that of the connecting rigging of the first temporary counterweight by a certain length, so that the second temporary counterweight does not need to be lowered to the seabed when the second temporary counterweight is lowered to complete the connection of the permanent anchoring rigging of the dynamic riser, and the collision to the anchoring base of the dynamic riser can be effectively avoided.

And the ship crane lifts the second temporary counterweight into water to the depth of the anchoring clamp of the dynamic riser, the crane heave compensation function is started, the laying ship approaches the anchoring clamp from the side surface of the dynamic riser route, and the ROV is used for connecting the connecting rigging of the second temporary counterweight with the branch rigging on the suspension rigging.

The temporary counter weight of second is transferred to the boats and ships loop wheel machine, and the hoist rigging of the temporary counter weight of second should have sufficient length and use soft suspender, and the temporary counter weight of second is transferred to the loop wheel machine like this, lets soft suspender contact dynamic riser, guarantees that the lifting hook does not contact with dynamic riser in the top of dynamic riser to guarantee that dynamic riser is not damaged. The ROV follows the downward movement of the second temporary counter weight, the second temporary counter weight pulls down the anchoring card of the dynamic riser, the ROV pulls the permanent anchoring rigging apart, the tail end of the permanent anchoring rigging is pulled to the anchoring point position of the anchoring base, attention is paid to the pulling route, the permanent anchoring rigging is prevented from being wound or interfered with the suspension rigging, and then the permanent anchoring rigging is connected to the anchoring point of the anchoring base.

The ship crane lifts the second temporary counterweight, the connecting rigging and the hanging rigging between the second temporary counterweight and the dynamic vertical pipe anchoring clamp are loosened, the permanent anchoring rigging pulls the anchoring clamp with force, and the ROV unlocks the loosened connecting rigging.

The ship crane switches the heave compensation mode to the normal hoisting mode, the second temporary counter weight is recovered to the ship deck, the ROV unlocks a loose suspension rigging, a rigging for arranging the first temporary counter weight and the third temporary counter weight on the seabed, and the ship crane enters water and recovers the first temporary counter weight and the third temporary counter weight to the deck.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes performed by the present specification and drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. An underwater connection method of a dynamic flexible pipe cable and an anchoring base is characterized by comprising the following steps:

2. The underwater connection method of a dynamic flexible umbilical to an anchor base of claim 1, wherein in step S1, one end of a permanent anchor rigging is connected to the attachment element of the dynamic flexible umbilical on a laying vessel; temporarily fixing the permanent anchor rigging axially to the dynamic flexible umbilical;

3. The underwater connection method of a dynamic flexible umbilical to an anchor base of claim 1, wherein in step S1, one end of a suspension rigging is connected to the attachment element and the suspension rigging is folded and temporarily fixed to the attachment element;

4. The underwater connection method of a dynamic flexible umbilical to an anchor foundation of claim 1 wherein in step S1, one end of a suspension rigging is first connected to the attachment element and the other end of the suspension rigging is connected to a first temporary counterweight;

5. The method of claim 1, wherein in step S2, the portion of the dynamic flexible umbilical above the attachment element is buoyant and the first temporary weight pulls the portion of the dynamic flexible umbilical above the attachment element away from the hull structure under the influence of gravity.

6. The method of claim 5, wherein in step S3, a third temporary weight is lowered into the water and connected in series with the first temporary weight to counteract the buoyancy of the float on the dynamic flexible umbilical so that the dynamic flexible umbilical is always far away from the hull structure during lowering.

7. The method of claim 1, wherein in step S1, a branch rigging is connected to the suspension rigging;

8. The method of subsea connection of a dynamic flexible umbilical to an anchor base of claim 7, wherein the second temporary weight is landed on the sea bed or suspended below the attachment element when the distance between the attachment element and the anchor base is less than the length of the permanent anchor rigging.

9. The method of subsea connection of a dynamic flexible umbilical to an anchor base as claimed in any of claims 1 to 8, further comprising the steps of:

10. The method of claim 9, wherein step S6 includes: