A method for underwater online replacement of dynamic cable-distributed floats

Abstract

This invention discloses a method for underwater online replacement of dynamic cable-driven distributed floats, comprising the following steps: developing a diving and surfacing operation plan based on the required water depth for float replacement; divers underwater dismantling the dynamic cable-driven float and its inner clamp; divers determining and marking the float installation position based on the float spacing information in the dynamic cable configuration diagram; the work vessel lowering the new float inner clamp and hydraulic installation tools to the vicinity of the marked position, where divers install the new float inner clamp; the work vessel lowering buoyancy blocks and installation fixtures to the vicinity of the marked position, where divers assemble the buoyancy blocks and the new float inner clamp, and then double-tightening them using fasteners and external clamping strips; and the work vessel retrieving the installation fixtures, completing the underwater online float replacement. This invention eliminates the need to detach the dynamic cable from the float, return it to the engineering vessel for repair, and then re-lay and reconnect it to the float, reducing construction work, optimizing the construction procedure, and achieving cost reduction and efficiency improvement.

Description

Technical Field

[0001] This invention relates to the field of cable maintenance technology, and in particular to a method for underwater online replacement of dynamic cable distributed floats. Background Technology

[0002] Floating production facilities are widely used in the oil and gas and offshore wind power sectors, with their underwater facilities such as mooring systems and cable systems also being extensively deployed. Among these, the dynamic cable serves as the sole transmission channel for signals, energy, and production materials within the floating production facility, and its integrity is crucial for the facility itself and the entire oilfield and wind farm. The buoy, a vital component of the dynamic cable, is essential for maintaining its catenary configuration in seawater and resisting the effects of wave and current loads, thus ensuring the safety and integrity of the dynamic cable buoy.

[0003] Currently, the underwater dynamic cable design for FPSOs in China has been in service for many years. However, the distributed buoyancy blocks of the dynamic cable have experienced displacement or detachment. Except for some facilities that have been evaluated and allowed to be abandoned, most of the underwater dynamic cables of FPSOs require repair work. For example, the dynamic cable is detached from a single point, pulled back to the engineering vessel for repair, and then re-laid and reconnected to the single point. This involves a large amount of construction work, complicated procedures, and requires a lot of ship days. In order to save ship days and achieve cost reduction and efficiency improvement, it is necessary to study and design an underwater online replacement method for the distributed buoyancy blocks of the dynamic cable. Summary of the Invention

[0004] The purpose of this invention is to provide a method for underwater online replacement of dynamic cable distributed floats. This method allows for the maintenance and replacement of floating facilities on-site without detaching the dynamic cable. It eliminates the need to detach the dynamic cable from the float, return it to the engineering vessel for repair, and then re-lay and reconnect it to the float. This reduces the amount of construction work, optimizes the construction process, saves engineering vessel days, and achieves cost reduction and efficiency improvement.

[0005] To achieve the objective of this invention, a method for underwater online replacement of a dynamic cable-driven distributed float is provided, comprising the following steps:

[0006] S1. Develop a diving and surfacing operation plan based on the water depth at which the float needs to be replaced;

[0007] S2. Divers go underwater to remove the dynamic cable float, and then remove the float inner clamp underwater. The float and float inner clamp are then hoisted to the deck by the engineering vessel.

[0008] S3. Divers determine and mark the float installation positions based on the float spacing information in the dynamic cable configuration diagram.

[0009] S4. The work vessel lowers the new float inner clamp and hydraulic installation tools to the vicinity of the marked position, and the divers install the new float inner clamp at the marked position;

[0010] S5. The work vessel lowers the buoyancy block and installs the tooling to the vicinity of the marked position. After the divers complete the assembly of the buoyancy block and the new float inner clamp, they double-tighten it with fasteners and outer strips.

[0011] S6. The work vessel retrieves and installs the tooling, completing the underwater online replacement of the float.

[0012] As a preferred technical solution of the present invention, the underwater removal of the float in step S2 includes: a diver going underwater to find the float that needs to be repaired and removing marine organisms from the float; the engineering vessel lowering a counterweight to the vicinity of the float, and the diver connecting the float to the counterweight; the diver disconnecting the float from the outer tread of the dynamic cable, and the engineering vessel lifting and recovering the float to the deck of the work vessel.

[0013] As a preferred technical solution of the present invention, the underwater removal of the float inner clamp in step S2 includes: the engineering vessel lowering the hydraulic tooling for the float inner clamp; the diver using the hydraulic tooling to fix it to the float inner clamp and connecting the hydraulic pipe; the engineering vessel pressurizing the hydraulic tooling to squeeze the fasteners of the float inner clamp, loosening the nuts on the fasteners of the float inner clamp, and then removing the bolts and nuts; the engineering vessel depressurizing the hydraulic tooling, and the diver removing the float inner clamp and the hydraulic tooling; the engineering vessel lifting and recovering the float inner clamp and the hydraulic tooling to the deck of the work vessel.

[0014] As a preferred technical solution of the present invention, in step S3, the float spacing information of the dynamic cable configuration diagram is based on the floats near the float that need to be repaired that have not been displaced.

[0015] As a preferred technical solution of the present invention, the installation of the new float inner clip in step S4 includes: at the marked new float installation position, the engineering vessel lowers the inner clip and hydraulic tooling; the diver opens the inner clip and fixes it at the marked position of the dynamic cable; after wrapping the fastening tape and inserting the fastener, the float is tightened using a hydraulic installation tool; the engineering vessel retrieves the hydraulic tooling.

[0016] As a preferred technical solution of the present invention, the installation of the buoyancy blocks in step S5 includes: hoisting the buoyancy blocks onto the installation fixture on the deck of the engineering vessel for assembly, and adjusting the angle of the hoisting rigging of the installation fixture according to the angle of the float at the installation position; lowering the buoyancy blocks and installation fixture from the engineering vessel; divers pulling the buoyancy blocks and installation fixture to the inner clamp position of the float, adjusting to complete the assembly of the buoyancy blocks and the inner clamp of the float; fixing the two buoyancy blocks onto the inner clamp of the float using fasteners and external cable ties; and retrieving the installation fixture from the engineering vessel.

[0017] As a preferred technical solution of the present invention, the installation fixture is adapted to the shape and size of the buoyancy block. The installation fixture is designed as a half-box structure with a hinge structure for opening and closing the fixture. After the hinge structure is opened, the opening of the fixture is at a fixed angle. The opening angle of the installation fixture is adapted to the inner size of the float. The steel structure beam of the installation fixture has several water inlet and outlet holes. The side end of the installation fixture is equipped with a counterweight and a lifting lug. The counterweight is adapted to the net buoyancy of the buoyancy block. The installation fixture is fixed to the buoyancy block by a pin, and the pin is fixed to the installation fixture by a chain.

[0018] As a preferred technical solution of the present invention, the cranes of engineering vessels are all equipped with counterweights when they are launched into the water.

[0019] Compared with the prior art, the present invention provides a method for underwater online replacement of dynamic cable-distributed floats, which has the following advantages:

[0020] This invention comprises two aspects: underwater removal of dynamic cable floats and online underwater installation of dynamic cable floats. First, a diving and surfacing operation plan is specified based on the water depth required for float replacement. After entering the water, the diver locates the float to be removed, clears away marine life, and observes the float's displacement. The diver checks if the displaced float is close to the nearest float. If not, a small-tonnage sling or nylon rope is threaded through the buoyancy block's lifting hole, and then a counterweight is lowered and connected to it; alternatively, the engineering vessel directly lowers the installation tool, and the diver pulls the tool to the float removal location, adjusts its position, secures the old float, removes the old cable ties from the old float, and retrieves it to the deck. If a float is found to be close to an adjacent float, a lever hoist needs to be installed on the cable near the float to be replaced. The float is then pulled to allow a small-tonnage sling or nylon rope to pass through the lifting hole on the float's buoyancy block. Then, a counterweight is lowered and connected to the already installed sling or nylon rope. After removing the old cable ties on the buoyancy block, the net buoyancy of the buoyancy block will not cause it to float up and affect diving safety due to the effect of the counterweight. Finally, hydraulic tools are lowered to apply pressure, the fastening nuts on the inner buoy clamp are removed, and the inner buoy clamp is then removed. Based on the buoy spacing information on the dynamic cable configuration diagram, the original position of the displaced buoy is determined and marked. The new inner buoy clamp and hydraulic installation tools are lowered to the marked position. The diver pulls the inner buoy clamp and hydraulic installation tools to the installation position and installs the inner buoy clamp at the marked position. The buoyancy blocks are hoisted onto the installation fixture from the deck of the engineering vessel and assembled. According to the buoy angle at the installation position, the angle of the hoisting rigging of the installation fixture is adjusted so that the buoyancy blocks and the installation fixture enter the water at a certain angle. After reaching the designated depth, the diver pulls the fixture to the inner buoy position, adjusts it so that the buoyancy blocks and the inner buoy clamp are assembled, closes the installation fixture, and then inserts fasteners and outer cable ties to fix the two buoyancy blocks on the inner buoy clamp. Finally, the installation fixture is retrieved.

[0021] The beneficial effects of this invention are as follows: Currently, there is no precedent in China for underwater online replacement of dynamic cable floats. The implementation of this method provides certain experience for subsequent similar projects and is applicable to the repair of dynamic cable floats in water depths of up to 300 meters. Furthermore, compared to detaching the dynamic cable, transferring it to an engineering vessel for repair, and then laying and reconnecting it, this method improves construction efficiency, saves construction costs, and makes dynamic cable repair operations more energy-efficient and effective. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the removal of the float buoyancy block and the float internal clip of the present invention;

[0023] Figure 2 This is a schematic diagram of the installation of the float internal card of the present invention;

[0024] Figure 3 This is a schematic diagram of the installation of the float buoyancy block of the present invention.

[0025] 1 is the dynamic cable, 2 is the float, 3 is the engineering vessel, 4 is the counterweight, 5 is the diver, 6 is the float internal clamp, 7 is the hydraulic installation tool, and 8 is the installation fixture. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Please see Figures 1-3 This invention provides a method for underwater online replacement of a dynamic cable-driven distributed float, comprising the following steps:

[0028] S1. Develop a diving and surfacing operation plan based on the water depth at which the float needs to be replaced;

[0029] S2. Divers go underwater to remove the dynamic cable float, and then remove the float inner clamp underwater. The float and float inner clamp are then hoisted to the deck by the engineering vessel.

[0030] S3. Divers determine and mark the float installation positions based on the float spacing information in the dynamic cable configuration diagram.

[0031] S4. The work vessel lowers the new float inner clamp and hydraulic installation tools to the vicinity of the marked position, and the divers install the new float inner clamp at the marked position;

[0032] S5. The work vessel lowers the buoyancy block and installs the tooling to the vicinity of the marked position. After the divers complete the assembly of the buoyancy block and the new float inner clamp, they double-tighten it with fasteners and outer strips.

[0033] S6. The work vessel retrieves and installs the tooling, completing the underwater online replacement of the float.

[0034] In one embodiment of the present invention, the underwater removal of the float in step S2 includes: a diver going underwater to find the float that needs to be repaired and removing marine organisms from the float; the engineering vessel lowering a counterweight to the vicinity of the float, and the diver connecting the float to the counterweight; the diver disconnecting the float from the outer strip of the dynamic cable, and the engineering vessel lifting and recovering the float to the deck of the work vessel.

[0035] In one embodiment of the present invention, the underwater removal of the float inner clamp in step S2 includes: the engineering vessel lowering the hydraulic tooling for the float inner clamp; the diver using the hydraulic tooling to fix it to the float inner clamp and connecting the hydraulic pipe; the engineering vessel pressurizing the hydraulic tooling to squeeze the fasteners of the float inner clamp, loosening the nuts on the fasteners of the float inner clamp, and then removing the bolts and nuts; the engineering vessel depressurizing the hydraulic tooling, and the diver removing the float inner clamp and the hydraulic tooling; and the engineering vessel lifting and recovering the float inner clamp and the hydraulic tooling to the deck of the work vessel.

[0036] In one embodiment of the present invention, the float spacing information in the dynamic cable configuration diagram in step S3 is based on the floats near the float that need to be repaired that have not been displaced.

[0037] In one embodiment of the present invention, the installation of the new float inner clip in step S4 includes: at the marked new float installation position, the engineering vessel lowers the inner clip and hydraulic tooling; the diver opens the inner clip and fixes it at the marked position on the dynamic cable; after wrapping with fastening tape and inserting fasteners, the float is tightened using a hydraulic installation tool; the engineering vessel retrieves the hydraulic tooling.

[0038] In one embodiment of the present invention, the installation of the buoyancy blocks in step S5 includes: hoisting the buoyancy blocks onto the installation fixture on the deck of the engineering vessel for assembly, and adjusting the angle of the hoisting rigging of the installation fixture according to the angle of the float at the installation position; lowering the buoyancy blocks and installation fixture from the engineering vessel; divers pulling the buoyancy blocks and installation fixture to the inner clamp position of the float, adjusting to complete the assembly of the buoyancy blocks and the inner clamp of the float; fixing the two buoyancy blocks onto the inner clamp of the float using fasteners and external cable ties; and retrieving the installation fixture from the engineering vessel.

[0039] In one embodiment of the present invention, the installation fixture is adapted to the shape and size of the buoyancy block. The installation fixture is a half-box structure with a hinge structure for opening and closing the fixture. After the hinge structure is opened, the opening of the fixture is at a fixed angle. The opening angle of the installation fixture is adapted to the inner size of the float. The steel structure beam of the installation fixture has several water inlet and outlet holes. The side end of the installation fixture is equipped with a counterweight and a lifting lug. The counterweight is adapted to the net buoyancy of the buoyancy block. The installation fixture is fixed to the buoyancy block by a pin, and the pin is fixed to the installation fixture by a chain.

[0040] In one embodiment of the present invention, the cranes of the engineering vessels are all equipped with counterweights when they are launched into the water.

[0041] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for underwater online replacement of a dynamic cable-driven distributed float, characterized in that, Includes the following steps: S1. Develop a diving and surfacing operation plan based on the water depth at which the float needs to be replaced; S2. Divers go underwater to remove the dynamic cable float, and then remove the float inner clamp underwater. The float and float inner clamp are then hoisted to the deck by the engineering vessel. S3. Divers determine and mark the float installation positions based on the float spacing information in the dynamic cable configuration diagram. S4. The work vessel lowers the new float inner clamp and hydraulic installation tools to the vicinity of the marked position, and the divers install the new float inner clamp at the marked position; S5. The work vessel lowers the buoyancy block and installs the tooling to the vicinity of the marked position. After the divers complete the assembly of the buoyancy block and the new float inner clip, they double-tighten it with fasteners and external straps. S6. The work vessel retrieves and installs the tooling, completing the underwater online replacement of the float.

2. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: The underwater removal of the float in step S2 includes: divers going underwater to locate the float that needs repair and removing marine organisms from the float; the engineering vessel lowering a counterweight to the vicinity of the float, and the divers connecting the float to the counterweight; the divers disconnecting the float from the external cable tie of the dynamic cable, and the engineering vessel lifting and recovering the float to the deck of the work vessel.

3. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: The underwater removal of the float inner clamp in step S2 includes: the engineering vessel lowering the hydraulic tooling for the float inner clamp; the diver using the hydraulic tooling to fix it to the float inner clamp and connecting the hydraulic pipe; the engineering vessel pressurizing the hydraulic tooling, which squeezes the fasteners of the float inner clamp, loosening the nuts on the fasteners of the float inner clamp, and then removing the bolts and nuts; the engineering vessel depressurizing the hydraulic tooling, and the diver removing the float inner clamp and the hydraulic tooling; and the engineering vessel lifting and recovering the float inner clamp and the hydraulic tooling to the deck of the work vessel.

4. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: In step S3, the float spacing information in the dynamic cable configuration diagram is based on the floats near the float that need to be repaired that have not been displaced.

5. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: The installation of the new float inner clamp in step S4 includes: at the marked new float installation position, the engineering vessel lowers the inner clamp and hydraulic tooling; the diver opens the inner clamp and fixes it at the marked position on the dynamic cable; after wrapping with fastening tape and inserting fasteners, the float is tightened using hydraulic installation tools; the engineering vessel retrieves the hydraulic tooling.

6. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: The installation of the buoyancy blocks in step S5 includes: hoisting the buoyancy blocks onto the installation fixture on the deck of the engineering vessel for assembly, and adjusting the angle of the hoisting rigging of the installation fixture according to the angle of the float at the installation position; lowering the buoyancy blocks and installation fixture from the engineering vessel; divers pulling the buoyancy blocks and installation fixture to the inner clamp position of the float, and adjusting to complete the assembly of the buoyancy blocks with the inner clamp of the float; fixing the two buoyancy blocks to the inner clamp of the float using fasteners and external cable ties; and retrieving the installation fixture from the engineering vessel.

7. A method for underwater online replacement of a dynamic cable-driven distributed float according to claim 6, characterized in that: The installation fixture is adapted to the shape and size of the buoyancy block. The installation fixture is designed as a half-box structure with a hinge structure for opening and closing the fixture. After the hinge structure is opened, the opening of the fixture is at a fixed angle. The opening angle of the installation fixture is adapted to the size of the inner clip of the float. Several water inlet and outlet holes are opened on the steel structure beam of the installation fixture, and a counterweight and lifting lug are installed on the side of the installation fixture. The counterweight is adapted to the net buoyancy of the buoyancy block. The installation fixture is fixed to the buoyancy block by a pin, and the pin is fixed to the installation fixture by a chain.

8. The method for underwater online replacement of a dynamic cable-driven distributed float according to claim 1, characterized in that: The cranes on engineering vessels are all equipped with counterweights when they are launched into the water.

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