A kind of S-lay online installation construction method of riser flexible joint

Abstract

The present invention discloses a method for online installation and construction of a riser flexible joint S-lay, which includes the following steps: inspecting and preparing the flexible joint; centering and welding the flexible joint with the prefabricated extension pipe on the operation line, performing non-destructive testing on the weld position and coating the outer surface; installing the towing head, and performing an external back pressure test to check the sealing performance; installing a strain control transition device, which is connected to the winch by steel cable power; moving the ship forward and releasing the prefabricated extension pipe synchronously, monitoring the process of the flexible joint passing through the stern and the roller of the stinger rack to avoid jamming; until the flexible joint is placed on the seabed, the connection of the steel cable is released, and the installation process of the flexible joint is completed. The present invention solves the problem of local stress concentration when the flexible joint passes through the operation line through the flexible joint installation process and the strain control transition device, which can greatly improve the installation operation efficiency, reduce the operation risk, and save the project cost.

Description

Technical Field

[0001] The invention relates to the technical field of riser facility installation, and in particular to an online installation construction method for a riser flexible joint S-lay. Background Art

[0002] In the development of deepwater oil and gas fields, steel catenary risers have the characteristics of low cost, great adaptability to floating body movement, and suitability for high temperature and high pressure working environment. They account for a large proportion of various types of risers on deep-sea platforms and have broad application prospects.

[0003] There are two main types of load-bearing joint components for steel catenary risers. One is the flexible joint, which is composed of a combination of rigid and elastomeric materials and can adapt to deformation caused by angle changes within a certain range. The other is the tapered stress joint, which is a specially designed riser joint with a tapered cross-section to control curvature and reduce local bending stress. In engineering, installing a flexible joint on the top of the steel catenary riser can reduce the angle of connection between the riser and the floating catenary. The flexible joint is a passive elastic element and is widely used in deepwater steel catenary risers.

[0004] In most cases, the external dimensions of the flexible joint are several times the outer diameter of the pipe connected thereto. When an S-shaped pipe-laying vessel is used for installation, greater local stress and / or strain will be generated near the flexible joint, causing the pipe to buckle. Summary of the invention

[0005] The purpose of the present invention is to provide an online installation construction method for a riser flexible joint S-lay, so as to solve the problem of local stress concentration when the flexible joint passes through an operation line.

[0006] In order to achieve the purpose of the present invention, the present invention provides a riser flexible joint S-lay online installation construction method, comprising the following steps:

[0007] S1. Take the flexible joint and perform pre-installation inspection and preparation on the flexible joint;

[0008] S2, aligning and welding the flexible joint and the prefabricated extension pipe on the production line, performing non-destructive testing on the weld position of the flexible joint and the prefabricated extension pipe and performing external surface coating treatment;

[0009] S3, installing a drag seal at the end of the flexible joint away from the prefabricated extension pipe, and performing an external back pressure test to check the sealing performance;

[0010] S4, connecting a strain control transition device to the end of the towing head away from the flexible joint, wherein the strain control transition device is connected to the winch through a steel cable power;

[0011] S5, moving the ship forward and releasing the prefabricated extension pipe synchronously, converting the laying tension of the prefabricated extension pipe from the tensioner to the winch, and monitoring the process of the flexible joint passing through the stern and the roller of the stinger to avoid jamming;

[0012] S6. Continue to move the ship forward and simultaneously release the prefabricated extension pipe until the flexible joint is placed on the seabed, the connection of the steel cable is released, and the installation process of the flexible joint is completed.

[0013] As a preferred technical solution of the present invention, a flexible joint protection cover is provided on the surface of the flexible joint.

[0014] As a preferred technical solution of the present invention, the dragging head is fixedly connected to the end of the flexible joint away from the prefabricated extension pipe through a flange, and a lifting ring is provided at the end of the dragging head away from the flange.

[0015] As a preferred technical solution of the present invention, the strain control transition device includes a transition tube body, the outer diameter of the transition tube body is close to the outer diameter of the flexible joint, and the two ends of the transition tube body are respectively connected with a hook and an ear plate, the outer diameter of the hook and the ear plate are smaller than the outer diameter of the transition tube body, the hook is connected to the lifting ring, and the ear plate is connected to the steel cable.

[0016] As a preferred technical solution of the present invention, a plurality of water-permeable holes are provided on the outer wall of the transition tube body.

[0017] As a preferred technical solution of the present invention, the hook is connected to the lifting ring through a ring buckle, and a shackle is provided at the connection between the ring buckle and the lifting ring.

[0018] Compared with the prior art, the present invention provides an online installation construction method for a riser flexible joint S-lay, which has the following beneficial effects:

[0019] The present invention can achieve the purpose of strain control by connecting a strain control transition device with an outer diameter similar to that of the flexible joint, and the two ends of the strain control transition device have a smooth transition, which can simultaneously meet the needs of pipe abandonment and recovery, and at the same time reduce the risk of the flexible joint getting stuck when passing through the rollers of the stinger rack. The length of the strain control transition device depends on the roller spacing of the stinger rack, and the design basis is to meet the requirement of spanning the spacing of two groups of rollers at the same time. The transition pipe body is designed with a water-permeable hole, which can achieve internal and external water pressure balance in water, and is suitable for deep-water pipeline installation operations. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the connection between the flexible joint and the strain control transition device of the present invention;

[0021] Figure 2 It is a schematic diagram of the structure of the flexible joint of the present invention;

[0022] Figure 3 It is a schematic diagram of the structure of the strain control transition device of the present invention.

[0023] 1 is a flexible joint, 2 is a prefabricated extension pipe, 3 is a drag head, 4 is a strain control transition device, 5 is a flexible joint protective cover, 6 is a flange, 7 is a lifting ring, 8 is a transition pipe body, 9 is a lifting hook, 10 is an ear plate, 11 is a water permeable hole, 12 is a ring buckle, and 13 is a shackle. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] See also Figure 1-Figure 3 The embodiment of the present invention provides a method for online installation and construction of a riser flexible joint S-lay, comprising the following steps:

[0026] S1. Take the flexible joint 1 and perform pre-installation inspection and preparation on the flexible joint 1;

[0027] S2, aligning and welding the flexible joint 1 and the prefabricated extension pipe 2 on the production line, performing non-destructive testing on the weld position of the flexible joint 1 and the prefabricated extension pipe 2 and performing external surface coating treatment;

[0028] S3, installing a drag seal 3 at the end of the flexible joint 1 away from the prefabricated extension pipe 2, and performing an external back pressure test to check the sealing performance;

[0029] S4, connecting a strain control transition device 4 to the end of the dragging head 3 away from the flexible joint 1, wherein the strain control transition device 4 is connected to the winch through a steel cable power;

[0030] S5, moving the ship forward and releasing the prefabricated extension pipe 2 synchronously, converting the laying tension of the prefabricated extension pipe 2 from the tensioner to the winch, monitoring the process of the flexible joint 1 passing through the stern and the roller of the stinger to avoid jamming;

[0031] S6. Continue to move the ship forward and simultaneously release the prefabricated extension pipe 2 until the flexible joint 1 is placed on the seabed, the connection of the steel cable is released, and the installation process of the flexible joint 1 is completed.

[0032] In one embodiment of the present invention, a flexible joint protection cover 5 is provided on the surface of the flexible joint 1 .

[0033] In one embodiment of the present invention, the dragging head 3 is fixedly connected to the end of the flexible joint 1 away from the prefabricated extension pipe 2 through a flange 6, and a lifting ring 7 is provided at the end of the dragging head 3 away from the flange 6.

[0034] In one embodiment of the present invention, the strain control transition device 4 includes a transition tube body 8, the outer diameter of the transition tube body 8 is similar to the outer diameter of the flexible joint 1, and the two ends of the transition tube body 8 are respectively connected to a hook 9 and an ear plate 10, the outer diameters of the hook 9 and the ear plate 10 are smaller than the outer diameter of the transition tube body 8, the hook 9 is connected to the lifting ring 7, and the ear plate 10 is connected to the steel cable.

[0035] In one embodiment of the present invention, a plurality of water permeable holes 11 are formed on the outer wall of the transition pipe body 8 .

[0036] In one embodiment of the present invention, the hook 9 is connected to the lifting ring 7 via a ring buckle 12 , and a shackle 13 is provided at the connection between the ring buckle 12 and the lifting ring 7 .

[0037] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for online installation and construction of a riser flexible joint S-lay, characterized in that: The following steps are involved: S1. Take the flexible joint (1), and perform pre-installation inspection and preparation on the flexible joint (1); S2, aligning and welding the flexible joint (1) and the prefabricated extension pipe (2) on the operation line, performing non-destructive testing on the weld position of the flexible joint (1) and the prefabricated extension pipe (2), and performing coating treatment on the outer surface; S3, installing a drag seal (3) at the end of the flexible joint (1) away from the prefabricated extension pipe (2), and performing an external back pressure test to check the sealing performance, wherein the drag seal (3) is fixedly connected to the end of the flexible joint (1) away from the prefabricated extension pipe (2) via a flange (6), and a lifting ring (7) is provided at the end of the drag seal (3) away from the flange (6); S4, a strain control transition device (4) is connected to the end of the towing head (3) away from the flexible joint (1), the strain control transition device (4) is connected to the winch through the power of the steel cable, the strain control transition device (4) comprises a transition tube (8), the outer diameter of the transition tube (8) is close to the outer diameter of the flexible joint (1), the two ends of the transition tube (8) are respectively connected with a hook (9) and an ear plate (10), the outer diameter of the hook (9) and the ear plate (10) are smaller than the outer diameter of the transition tube (8), the hook (9) is connected to the lifting ring (7), and the ear plate (10) is connected to the steel cable; S5, moving the ship forward and simultaneously releasing the prefabricated extension pipe (2), converting the laying tension of the prefabricated extension pipe (2) from the tensioner to the winch, and monitoring the process of the flexible joint (1) passing through the stern and the stinger roller to avoid jamming; S6. Continue to move the ship forward and simultaneously release the prefabricated extension pipe (2) until the flexible joint (1) is placed on the seabed, the connection of the steel cable is released, and the installation process of the flexible joint (1) is completed.

2. According to claim 1, a method for online installation and construction of a riser flexible joint S-lay, characterized in that: A flexible joint protection cover (5) is provided on the surface of the flexible joint (1).

3. According to claim 1, a method for online installation and construction of a riser flexible joint S-lay, characterized in that: The outer wall of the transition pipe body (8) is provided with a plurality of water permeable holes (11).

4. According to claim 1, a method for online installation and construction of a riser flexible joint S-lay, characterized in that: The hook (9) is connected to the lifting ring (7) via a ring buckle (12), and a shackle (13) is provided at the connection between the ring buckle (12) and the lifting ring (7).

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