Method for laying submarine cable based on discarded marine oil and gas pipeline

Abstract

The invention relates to a method for laying a submarine cable based on a discarded marine oil and gas pipeline. The method comprises the following steps: presetting four bidirectional hanging rings on a steel cable; a steel cable with four bidirectional hanging rings is arranged in an oil and gas pipeline of the old offshore facility in a penetrating mode; a first expansion bend and a second expansion bend of an oil and gas pipeline of the old offshore facility are dismantled; the underwater robot repairs the originally damaged steel cables to form a traction steel cable; and a cable is tied on the traction steel cable, and the cable is pulled through the traction steel cable, so that the cable penetrates through the second connecting vertical pipe, the discarded and sealed offshore oil and gas pipeline and the first connecting vertical pipe. According to the method for laying the submarine cable based on the discarded marine oil and gas pipeline, the submarine cable is laid in the discarded or sealed marine oil and gas pipeline, an independent routing right does not need to be applied, the approval period can be shortened, ditching burying is not needed, and the problems of seabed disturbance and sediment diffusion are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of integrated development of marine oil and gas and marine wind power resources, and in particular to a method for laying submarine cables based on abandoned marine oil and gas pipelines. Background Art

[0002] In the development of offshore oil and gas, submarine pipelines are abandoned and sealed when they reach the end of their service life or are corroded and perforated and have no value for repair. As offshore wind power is increasingly used in offshore oil and gas development, the oil and gas field power grid needs to be adaptively transformed and new submarine cables laid.

[0003] In the existing technology, submarine cable laying construction requires applying for separate route rights and using special cable laying vessels and burying plows. The construction approval cycle is long, and trenching and burying facilities will disturb the seabed and cause sediment to spread. At the same time, the cable trench takes a long time to silt up naturally, and it takes a long time to silt up to the designed burial depth. This problem is particularly serious for engineering projects where the pipeline cable route crosses the waterway.

[0004] At present, when laying cables near abandoned marine oil and gas pipelines, new pipelines are generally laid, which causes waste. There is a lack of a method for laying cables through old pipelines without laying new pipelines. Summary of the invention

[0005] In view of the above problems, the purpose of the present invention is to provide a method for laying submarine cables based on abandoned marine oil and gas pipelines, which is used to solve the problem that when laying cables near abandoned marine oil and gas pipelines, new pipelines are generally laid, resulting in waste, and there is a lack of a method for laying cables through old pipelines without laying new pipelines.

[0006] To achieve the above object, the present invention adopts the following technical solutions: The invention discloses a method for laying submarine cables based on abandoned marine oil and gas pipelines, comprising: Step A: Preset four two-way hanging rings on the steel cable; Step B: a steel cable with four bidirectional hanging rings is passed through the oil and gas pipeline of the old offshore facility until two of the bidirectional hanging rings on the steel cable correspond to the two ends of the first expansion bend respectively, and the other two bidirectional hanging rings correspond to the two ends of the second expansion bend respectively; Step C: dismantling the first expansion bend and the second expansion bend of the oil and gas pipeline of the old offshore facility, wherein the steel cable between the two corresponding bidirectional hanging rings in the first expansion bend is lifted away, and the steel cable between the two corresponding bidirectional hanging rings in the second expansion bend is lifted away; Step D: The underwater robot connects the two corresponding bidirectional hanging rings in the first expansion bend through hooks, and connects the two corresponding bidirectional hanging rings in the second expansion bend through hooks, and repairs the damaged steel cable to form a traction steel cable; Step E: Tie the cable to the traction steel cable, and pull the cable through the traction steel cable to make the cable pass through the second connecting riser, the abandoned and sealed marine oil and gas pipeline, and the first connecting riser, wherein the cable is passed through the oil and gas channel to become a submarine cable, and the first marine platform and the second marine platform are connected together through the submarine cable.

[0007] Specifically, step A includes the following steps: according to the positions of the first expansion bend and the second expansion bend in the oil and gas channel of the old offshore facility, a first two-way hanging ring, a second two-way hanging ring, a third two-way hanging ring and a fourth two-way hanging ring are respectively set on the steel cable in advance, wherein the first two-way hanging ring and the second two-way hanging ring respectively correspond to the two ends of the first expansion bend when the steel cable is completely passed through the oil and gas channel, and the third two-way hanging ring and the fourth two-way hanging ring respectively correspond to the two ends of the second expansion bend when the steel cable is completely passed through the oil and gas channel.

[0008] Specifically, the first bidirectional hanging ring, the second bidirectional hanging ring, the third bidirectional hanging ring and the fourth bidirectional hanging ring each include two hanging rings, and the outer diameter of the hanging ring is smaller than the inner diameter of the oil and gas channel; Both the first two-way hanging ring, the second two-way hanging ring, the third two-way hanging ring and the fourth two-way hanging ring can be hung with hooks; the hooks can connect the first two-way hanging ring and the second two-way hanging ring together or connect the third two-way hanging ring and the fourth two-way hanging ring together.

[0009] Specifically, the step B comprises the following steps: Step B1: a pulling construction vessel stops near the first offshore platform, the pulling construction vessel is loaded with a steel cable with four bidirectional hanging rings, one end of the steel cable is fixed on the pulling construction vessel, and the other end is fixed with a pipe cleaning ball; Step B2: Put the pipe cleaning ball into the ball launching tube of the first offshore platform, and launch the pipe cleaning ball into the first connecting riser through the ball launching tube of the first offshore platform; Step B3: The cleaning ball with the steel cable first passes through the first connecting riser, then passes through the abandoned and sealed marine oil and gas pipeline, and finally passes through the second connecting riser to reach the second marine platform, and the first two-way hanging ring and the second two-way hanging ring on the steel cable correspond to the two ends of the first expansion bend respectively, and the third two-way hanging ring and the fourth two-way hanging ring correspond to the two ends of the second expansion bend respectively.

[0010] Specifically, before the cleaning ball is arranged, a lubricating paste is applied on the cleaning ball.

[0011] Specifically, step C comprises the following steps: Step C1: first remove the first expansion bend, including the following specific steps: Dismantle the expansion bend flanges at both ends of the first expansion bend respectively connected to the first connecting riser and the abandoned and sealed marine oil and gas pipeline; Arranging a first steel cable connection joint on the first expansion bend; A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is docked with the first steel cable connection joint, the lifting steel cable is recovered and the first expansion bend is lifted away. At the same time, the steel cable between the first bidirectional hanging ring and the second bidirectional hanging ring corresponding to the first expansion bend is damaged due to being lifted away, and the removal of the first expansion bend is completed; Step C2: Removing the second expansion bend includes the following specific steps: Remove the expansion bend flanges at both ends of the second expansion bend that are respectively connected to the abandoned and sealed marine oil and gas pipeline and the second connecting riser; Arranging a second steel cable connection joint on the second expansion bend; A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is connected to the second steel cable connection joint, the lifting steel cable is recovered and the second expansion bend is lifted away. At the same time, the steel cable between the corresponding third two-way hanging ring and the fourth two-way hanging ring in the second expansion bend is damaged due to being lifted away, thereby completing the dismantling of the second expansion bend.

[0012] Specifically, in step D, the underwater robot connects the hanging ring of the first two-way hanging ring and the hanging ring of the second two-way hanging ring together through a hook, connects the hanging ring of the third two-way hanging ring and the hanging ring of the fourth two-way hanging ring together through a hook, and repairs the originally damaged steel cable to form a traction steel cable.

[0013] Specifically, the step E comprises the following steps: Step E1: a cable laying work vessel is pre-parked near the second offshore platform. The cable laying work vessel is loaded with cables. The cleaning ball on the traction steel cable is removed, and the cable is docked with the end of the traction steel cable from which the cleaning ball is removed; Step E2: Start the winch on the pulling construction ship to pull and recover the traction cable. Pull the traction cable at the end of the traction cable where no cable is passed through, so that the cable passes through the second connecting riser in turn, enters the abandoned and sealed marine oil and gas pipeline, and finally comes out of the first connecting riser until the cable reaches the pulling construction ship parked near the first marine platform.

[0014] Furthermore, the method further comprises: Step F: placing a first concrete bundling and a second concrete bundling respectively for protection at the exposed section of the submarine cable between the first offshore platform and the second offshore platform at both ends of the abandoned and sealed offshore oil and gas pipeline.

[0015] Specifically, the first concrete row and the second concrete row are both row assemblies composed of concrete test blocks.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (I) The present invention discloses a method for laying a submarine cable based on an abandoned marine oil and gas pipeline, comprising the following steps: presetting four bidirectional hanging loops on a steel cable; passing a steel cable with four bidirectional hanging loops through an oil and gas pipeline of an old offshore facility until two of the bidirectional hanging loops on the steel cable correspond to the two ends of a first expansion bend, respectively, and the other two bidirectional hanging loops correspond to the two ends of a second expansion bend, respectively; removing the first expansion bend and the second expansion bend of the oil and gas pipeline of the old offshore facility, wherein the steel cable between the two bidirectional hanging loops corresponding to the first expansion bend is lifted away, and the steel cable between the two bidirectional hanging loops corresponding to the second expansion bend is lifted away. The steel cable between the two connecting risers is lifted; the underwater robot connects the corresponding two bidirectional hanging rings in the first expansion bend together through hooks, and connects the corresponding two bidirectional hanging rings in the second expansion bend together through hooks, and the originally damaged steel cable is repaired and connected into a traction steel cable; the cable is tied to the traction steel cable, and the cable is towed by the traction steel cable, so that the cable passes through the second connecting riser, the abandoned and sealed marine oil and gas pipeline, and the first connecting riser, wherein the cable is passed through the oil and gas channel to become a submarine cable, and the first marine platform and the second marine platform are connected together through the submarine cable. The method for laying submarine cables based on abandoned marine oil and gas pipelines disclosed in the present invention utilizes the interior of abandoned or sealed marine oil and gas pipelines to lay submarine cables, which not only does not require the application of separate routing rights, but can also reduce the approval cycle, and does not require trenching and burying, avoiding the problem of disturbing the seabed and spreading sediment.

[0017] (II) The present invention discloses a method for laying submarine cables based on abandoned marine oil and gas pipelines, which also includes the steps of: placing first concrete row 31 and second concrete row for protection at the exposed sections of the submarine cables from the two ends of the abandoned and sealed marine oil and gas pipelines to the first marine platform and the second marine platform, i.e., at the positions of the original first expansion bend and the second expansion bend. The method for laying submarine cables based on abandoned marine oil and gas pipelines disclosed by the present invention utilizes the steel structure and covering soil of the submarine pipeline to provide better safety protection for the submarine cables, thereby reducing the risk of damage to the cables by the outside world. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of an old offshore facility with an abandoned marine oil and gas pipeline before construction provided by Example 1 of the present invention; Figure 2 is a schematic diagram of the structure of a new offshore facility with an abandoned marine oil and gas pipeline after construction provided by Example 2 of the present invention; Figure 3 It is a schematic diagram of the structure of the steel cable installed in the oil and gas channel of the old offshore facility provided by Example 3 of the present invention.

[0019] Explanation of reference numerals: 100 - abandoned and sealed marine oil and gas pipeline, 200 - submarine cable; A-first offshore platform, 11-first connecting riser, 21-first expansion bend, 31-first concrete row; B-second offshore platform, 12-second connecting riser, 22-second expansion bend, 32-second concrete bunk bed; 4-steel cable, 40-pipe cleaning ball; 41-a first two-way hanging ring, 42-a second two-way hanging ring, 43-a third two-way hanging ring, 44-a fourth two-way hanging ring. DETAILED DESCRIPTION

[0020] The exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0021] In order to solve the problem that at present, when laying cables near abandoned marine oil and gas pipelines, new pipelines are generally laid, resulting in waste, and there is a lack of a method for laying cables through old pipelines without laying new pipelines, the present invention discloses a method for laying submarine cables based on abandoned marine oil and gas pipelines, in which a submarine cable is inserted inside the abandoned or sealed submarine pipeline to provide a routing channel for the submarine cable, and at the same time, the steel structure of the submarine pipeline and the good covering conditions formed over the years are utilized to provide better safety protection for the submarine cable.

[0022] In order to explain the present invention in detail, a specific implementation case is used for description. A new submarine cable is needed between the two offshore platforms to transmit the current generated by the offshore wind turbine. It should be noted that a steel submarine oil and gas pipeline with a diameter of 406.4 mm has been sealed between the two offshore platforms. At the same time, the two offshore platforms are located on both sides of a busy offshore waterway, and the distance between the two offshore platforms is 2 kilometers. In the process of laying submarine cables, there are problems such as difficulty in approving the pipeline and cable routes and high protection requirements for crossing the waterway area.

[0023] Example 1: An old offshore facility with an abandoned marine oil and gas pipeline before construction Embodiment 1 of the present invention provides an old offshore facility with an abandoned marine oil and gas pipeline before construction, and its structure and connection relationship are described in detail below with reference to the accompanying drawings.

[0024] refer to Figure 1 The old offshore facility includes two offshore platforms, namely the first offshore platform A and the second offshore platform B.

[0025] The first offshore platform A and the second offshore platform B are both equipped with jackets; A first connecting riser 11 is arranged on the jacket of the first offshore platform A, and a second connecting riser 12 is arranged on the jacket of the second offshore platform B; An abandoned and sealed marine oil and gas pipeline 100 is laid on the seabed between the first marine platform A and the second marine platform B. The abandoned and sealed marine oil and gas pipeline 100 is an abandoned marine oil and gas pipeline.

[0026] The bottom end of the first connecting riser 11 is butted against the left end of the abandoned and sealed marine oil and gas pipeline 100 via a first expansion bend 21, and the right end of the abandoned and sealed marine oil and gas pipeline 100 is butted against the bottom end of the second connecting riser 12 via a second expansion bend 22, thereby realizing the sequential connection of the first connecting riser 11, the abandoned and sealed marine oil and gas pipeline 100, and the second connecting riser 12, forming an oil and gas channel between the first marine platform A and the second marine platform B.

[0027] Specifically, both ends of the first expansion bend 21 are connected to the first connecting riser 11 and the abandoned and sealed marine oil and gas pipeline 100 through expansion bend flanges; both ends of the second expansion bend 22 are connected to the abandoned and sealed marine oil and gas pipeline 100 and the second connecting riser 12 through expansion bend flanges.

[0028] The first offshore platform A and / or the second offshore platform B is provided with a ball launcher, which can launch a pipe cleaning ball 40 toward the first connecting riser 11 or the second connecting riser 12 , and the pipe cleaning ball 40 can move forward in the first connecting riser 11 or the second connecting riser 12 .

[0029] Example 2: A new offshore facility with an abandoned marine oil and gas pipeline after construction The new offshore facility with an abandoned marine oil and gas pipeline after construction provided in Example 2 of the present invention is described in detail below with reference to the accompanying drawings.

[0030] refer to Figure 2 And compare Figure 1 The new offshore facility is an improvement on the old offshore facility in Example 1, and the improvements are as follows: First, in order to reduce the influence of the expansion elbow on the towing load of the submarine cable and increase the towing length, based on Example 1, Example 2 removes the first expansion elbow 21 and the second expansion elbow 22 at both ends of the abandoned and sealed marine oil and gas pipeline 100.

[0031] Secondly, the route and pipeline facilities of the abandoned and sealed marine oil and gas pipeline 100 are fully utilized to realize the integration of marine oil and gas development and marine wind power resource development, and a submarine cable 200 is newly installed between the first marine platform A and the second marine platform B as a marine wind power submarine cable. The free end of the submarine cable 200 first passes through the first connecting riser 11, then passes through the abandoned and sealed marine oil and gas pipeline 100, and finally passes through the second connecting riser 12, or passes through the second connecting riser 12, then passes through the abandoned and sealed marine oil and gas pipeline 100, and finally passes through the first connecting riser 11, so as to connect the first marine platform A and the second marine platform B together.

[0032] Finally, in order to protect the exposed sections of the submarine cables between the two ends of the abandoned and sealed marine oil and gas pipeline 100 and the first marine platform A and the second marine platform B, the first concrete row 31 and the second concrete row 32 are placed respectively for protection on the exposed sections of the submarine cables between the left end of the abandoned and sealed marine oil and gas pipeline 100 and the first marine platform A and between the right end of the abandoned and sealed marine oil and gas pipeline 100 and the second marine platform B.

[0033] Specifically, the first concrete row 31 and the second concrete row 32 are both formed by connecting a plurality of concrete blocks in series in a row.

[0034] Example 3: A method for laying submarine cables based on abandoned marine oil and gas pipelines Embodiment 3 of the present invention provides a method for laying submarine cables based on abandoned marine oil and gas pipelines, which is used to change the old offshore facility of embodiment 1 into the new offshore facility of embodiment 2, and the method comprises the following steps: Step A: Preset four bidirectional hanging rings on the steel cable 4.

[0035] Specifically, according to the positions of the first expansion bend 21 and the second expansion bend 22 in the oil and gas channel of the old offshore facility, a first two-way hanging ring 41, a second two-way hanging ring 42, a third two-way hanging ring 43 and a fourth two-way hanging ring 44 are pre-arranged on the steel cable 4, respectively, wherein the first two-way hanging ring 41 and the second two-way hanging ring 42 respectively correspond to the two ends of the first expansion bend 21 when the steel cable 4 is completely passed through the oil and gas channel, and the third two-way hanging ring 43 and the fourth two-way hanging ring 44 respectively correspond to the two ends of the second expansion bend 22 when the steel cable 4 is completely passed through the oil and gas channel.

[0036] More specifically, the position of the first two-way hanging ring 41 on the steel cable 4 corresponds to the connection between the bottom end of the first connecting riser 11 of the steel cable 4 passing through the oil and gas channel and the left end of the first expansion bend 21; the position of the second two-way hanging ring 42 on the steel cable 4 corresponds to the connection between the right end of the first expansion bend 21 of the steel cable 4 passing through the oil and gas channel and the left end of the abandoned and sealed marine oil and gas pipeline 100; the position of the third two-way hanging ring 43 on the steel cable 4 corresponds to the connection between the right end of the abandoned and sealed marine oil and gas pipeline 100 of the steel cable 4 passing through the oil and gas channel and the left end of the second expansion bend 22; the position of the fourth two-way hanging ring 44 on the steel cable 4 corresponds to the connection between the right end of the second expansion bend 22 of the steel cable 4 passing through the oil and gas channel and the bottom end of the second expansion bend 22, as shown in FIG. Figure 3 shown.

[0037] The first two-way hanging ring 41 , the second two-way hanging ring 42 , the third two-way hanging ring 43 and the fourth two-way hanging ring 44 each include two hanging rings, and the outer diameter of the hanging ring is smaller than the inner diameter of the oil and gas channel.

[0038] Both the first two-way hanging ring 41, the second two-way hanging ring 42, the third two-way hanging ring 43 and the fourth two-way hanging ring 44 can be hung with hooks, and the hooks can connect the first two-way hanging ring 41 and the second two-way hanging ring 42 together or connect the third two-way hanging ring 43 and the fourth two-way hanging ring 44 together.

[0039] Step B: A steel cable 4 with four bidirectional hanging loops is inserted into the oil and gas pipeline of the old offshore facility of Example 1 until the first bidirectional hanging loop 41 and the second bidirectional hanging loop 42 on the steel cable 4 correspond to the two ends of the first expansion bend 21 respectively, and the third bidirectional hanging loop 43 and the fourth bidirectional hanging loop 44 correspond to the two ends of the second expansion bend 22 respectively, comprising the following steps: Step B1: a pulling construction vessel stops near the first offshore platform A, and a steel cable 4 with four bidirectional hanging rings is loaded on the pulling construction vessel, one end of the steel cable 4 is fixed on the pulling construction vessel, and a pipe cleaning ball 40 is fixed on the other end; Step B2: Put the pipe cleaning ball 40 into the ball launching tube of the first offshore platform A, and launch the pipe cleaning ball 40 into the first connecting riser 11 through the ball launching tube of the first offshore platform A; Step B3: The cleaning ball 40 with the steel cable 4 first passes through the first connecting riser 11, then passes through the abandoned and sealed marine oil and gas pipeline 100, and finally passes through the second connecting riser 12 to reach the second marine platform B, and the first two-way hanging ring 41 and the second two-way hanging ring 42 on the steel cable 4 correspond to the two ends of the first expansion bend 21 respectively, and the third two-way hanging ring 43 and the fourth two-way hanging ring 44 correspond to the two ends of the second expansion bend 22 respectively. Figure 3 shown.

[0040] Before the cleaning ball 40 is provided, a lubricating paste is applied to the cleaning ball 40 so that the cleaning ball 40 can lubricate the inside of the pipeline during the cleaning process to reduce friction during cable dragging.

[0041] In addition to the above-mentioned method, it is feasible to interchange the first offshore platform A and the second offshore platform B. This interchange is a common technical means in the art and should not be understood as a limitation on the method disclosed in Example 3 of the present invention. Another method is: A pulling construction vessel is parked near the second offshore platform B. A steel cable 4 with four bidirectional hanging rings is loaded on the pulling construction vessel. One end of the steel cable 4 is fixed on the pulling construction vessel, and a cleaning ball 40 is fixed on the other end. The cleaning ball 40 is then placed on the ball launcher of the second offshore platform B, and is sent into the second connecting riser 12 through the ball launcher of the second offshore platform B. The cleaning ball 40 carries the steel cable 4 and first passes through the second connecting riser 12, then passes through the abandoned and sealed offshore oil and gas pipeline 100, and finally passes through the first connecting riser 11 to reach the first offshore platform A. The first two-way hanging ring 41 and the second two-way hanging ring 42 on the steel cable 4 correspond to the two ends of the first expansion bend 21 respectively, and the third two-way hanging ring 43 and the fourth two-way hanging ring 44 correspond to the two ends of the second expansion bend 22 respectively.

[0042] For the convenience of description, Example 3 of the present invention continues to be described in the former manner.

[0043] Step C: dismantling the first expansion bend 21 and the second expansion bend 22 of the oil and gas pipeline of the old offshore facility, wherein the steel cable 4 between the first two-way hanging ring 41 and the second two-way hanging ring 42 corresponding to the first expansion bend 21 is lifted away, and the steel cable 4 between the third two-way hanging ring 43 and the fourth two-way hanging ring 44 corresponding to the second expansion bend 22 is lifted away, comprising the following steps: Step C1: first remove the first expansion bend 21, including the following specific steps: Dismantle the expansion bend flanges at both ends of the first expansion bend 21 that are respectively connected to the first connecting riser 11 and the abandoned and sealed marine oil and gas pipeline 100; A first steel cable connection joint is provided on the first expansion bend 21; A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is docked with the first steel cable connection joint, the lifting steel cable is recovered and the first expansion bend 21 is lifted away. At the same time, the steel cable 4 between the first bidirectional hanging ring 41 and the second bidirectional hanging ring 42 corresponding to the first expansion bend 21 is damaged by being lifted away, and the removal of the first expansion bend 21 is completed; Step C2: removing the second expansion bend 22, including the following specific steps: Remove the expansion bend flanges at both ends of the second expansion bend 22 that are respectively connected to the abandoned and sealed marine oil and gas pipeline 100 and the second connecting riser 12; A second steel cable connection joint is provided on the second expansion bend 22; A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is docked with the second steel cable connection joint, the lifting steel cable is recovered and the second expansion bend 22 is lifted away. At the same time, the steel cable 4 between the corresponding third two-way hanging ring 43 and fourth two-way hanging ring 44 in the second expansion bend 22 is damaged due to being lifted away, and the removal of the second expansion bend 22 is completed.

[0044] Among them, the floating crane can be replaced by a pulling construction vessel or a submarine cable laying work vessel that meets the functional requirements.

[0045] Step D: The underwater robot connects the first two-way hanging ring 41 and the second two-way hanging ring 42 together through a hook, and connects the third two-way hanging ring 43 and the fourth two-way hanging ring 44 together through a hook, and repairs the originally damaged steel cable to form a traction steel cable.

[0046] Wherein, the traction cable is arranged between the first offshore platform A and the second offshore platform B.

[0047] Step E: tying the cable to the traction steel cable, traction the cable by the traction steel cable, and passing the cable through the second connection riser 12, the abandoned and sealed marine oil and gas pipeline 100, and the first connection riser 11, wherein the cable is passed through the oil and gas channel to become a submarine cable 200, and the first marine platform A and the second marine platform B are connected together through the submarine cable 200, including the following steps: Step E1: a cable laying work vessel is pre-parked near the second offshore platform B. The cable laying work vessel is loaded with cables. The cleaning ball 40 on the traction steel cable is removed, and the cable is docked with one end of the traction steel cable from which the cleaning ball 40 is removed. Step E2: Start the winch on the pulling construction ship to pull and recover the traction cable. Pull the traction cable at the end of the traction cable where no cable is passed through, so that the cable passes through the second connecting riser 12 in turn, and enters the abandoned and sealed marine oil and gas pipeline 100, and finally comes out of the first connecting riser 11, until the cable reaches the pulling construction ship parked near the first marine platform A.

[0048] Step F: Place the first concrete bunk bed 31 and the second concrete bunk bed 32 for protection at the exposed section of the submarine cable 200 between the first offshore platform A and the second offshore platform B at both ends of the abandoned and sealed offshore oil and gas pipeline 100, i.e., at the positions of the original first expansion bend 21 and the second expansion bend 22.

[0049] The first concrete row 31 and the second concrete row 32 are both row assemblies composed of concrete test blocks.

[0050] By implementing the technical solution of the present invention, it is possible to realize that newly built submarine cables and abandoned submarine oil and gas pipelines share a route, and the submarine cables can be effectively protected by external submarine oil and gas pipelines, thereby simplifying the submarine cable route approval cycle, without affecting waterways or routes and reducing damage to the marine environment.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for laying submarine cables based on abandoned marine oil and gas pipelines, characterized in that: include Step A: Preset four bidirectional hanging rings on the steel cable (4); Step B: inserting a steel cable (4) with four bidirectional hanging rings into the oil and gas pipeline of the old offshore facility until two of the bidirectional hanging rings on the steel cable (4) correspond to the two ends of the first expansion bend (21) respectively, and the other two bidirectional hanging rings correspond to the two ends of the second expansion bend (22) respectively; Step C: dismantling the first expansion bend (21) and the second expansion bend (22) of the oil and gas pipeline of the old offshore facility, wherein the steel cable (4) between the two corresponding bidirectional hanging rings in the first expansion bend (21) is lifted away, and the steel cable (4) between the two corresponding bidirectional hanging rings in the second expansion bend (22) is lifted away; Step D: The underwater robot connects the corresponding two bidirectional hanging rings in the first expansion bend (21) together through hooks, and connects the corresponding two bidirectional hanging rings in the second expansion bend (22) together through hooks, and repairs the damaged steel cable to form a traction steel cable; Step E: The cable is tied to a traction steel cable, and the traction steel cable is used to pull the cable so that the cable passes through the second connection riser (12), the abandoned and sealed marine oil and gas pipeline (100), and the first connection riser (11), wherein the cable is passed through the oil and gas channel to become a submarine cable (200), and the first marine platform (A) and the second marine platform (B) are connected together through the submarine cable (200).

2. The method according to claim 1, characterized in that The step A comprises the following specific steps: According to the positions of the first expansion bend (21) and the second expansion bend (22) in the oil and gas channel of the old offshore facility, a first two-way hanging ring (41), a second two-way hanging ring (42), a third two-way hanging ring (43) and a fourth two-way hanging ring (44) are respectively arranged on the steel cable (4) in advance, wherein the first two-way hanging ring (41) and the second two-way hanging ring (42) respectively correspond to the two ends of the first expansion bend (21) when the steel cable (4) is completely inserted into the oil and gas channel, and the third two-way hanging ring (43) and the fourth two-way hanging ring (44) respectively correspond to the two ends of the second expansion bend (22) when the steel cable (4) is completely inserted into the oil and gas channel.

3. The method according to claim 2, characterized in that The first bidirectional hanging ring (41), the second bidirectional hanging ring (42), the third bidirectional hanging ring (43) and the fourth bidirectional hanging ring (44) each include two hanging rings, and the outer diameter of the hanging ring is smaller than the inner diameter of the oil and gas channel; Two of the first two-way hanging ring (41), the second two-way hanging ring (42), the third two-way hanging ring (43) and the fourth two-way hanging ring (44) can be provided with hooks; the hooks can connect the first two-way hanging ring (41) and the second two-way hanging ring (42) together or connect the third two-way hanging ring (43) and the fourth two-way hanging ring (44) together.

4. The method according to claim 2, characterized in that: The step B comprises the following steps: Step B1: a pulling construction vessel is parked near the first offshore platform (A), and a steel cable (4) with four bidirectional hanging rings is loaded on the pulling construction vessel, one end of the steel cable (4) is fixed to the pulling construction vessel, and a pipe cleaning ball (40) is fixed to the other end; Step B2: placing the pipe cleaning ball (40) on the ball launching tube of the first offshore platform (A), and launching the pipe cleaning ball (40) into the first connecting riser (11) through the ball launching tube of the first offshore platform (A); Step B3: The cleaning ball (40) carrying the steel cable (4) first passes through the first connecting riser (11), then passes through the abandoned and sealed marine oil and gas pipeline (100), and finally passes through the second connecting riser (12) to reach the second marine platform (B), and the first two-way hanging ring (41) and the second two-way hanging ring (42) on the steel cable (4) respectively correspond to the two ends of the first expansion bend (21), and the third two-way hanging ring (43) and the fourth two-way hanging ring (44) respectively correspond to the two ends of the second expansion bend (22).

5. The method according to claim 4, characterized in that Before the cleaning ball (40) is arranged, a lubricating paste is applied to the cleaning ball (40).

6. The method according to claim 4, characterized in that The step C comprises the following steps: Step C1: first remove the first expansion bend (21), including the following specific steps: Disassembling expansion bend flanges at both ends of the first expansion bend (21) that are respectively connected to the first connection riser (11) and the abandoned and sealed marine oil and gas pipeline (100); A first steel cable connection joint is provided on the first expansion bend (21); A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is docked with the first steel cable connection joint, the lifting steel cable is recovered and the first expansion bend (21) is lifted away. At the same time, the steel cable (4) between the first bidirectional hanging ring (41) and the second bidirectional hanging ring (42) corresponding to the first expansion bend (21) is damaged by being lifted away, thereby completing the removal of the first expansion bend (21); Step C2: removing the second expansion bend (22), including the following specific steps: Removing the expansion bend flanges at both ends of the second expansion bend (22) that are respectively connected to the abandoned and sealed marine oil and gas pipeline (100) and the second connecting riser (12); A second steel cable connection joint is provided on the second expansion bend (22); A lifting steel cable is lowered from the sea surface by a floating crane. After the lifting steel cable is docked with the second steel cable connection joint, the lifting steel cable is recovered and the second expansion bend (22) is lifted away. At the same time, the steel cable (4) between the corresponding third bidirectional hanging ring (43) and the fourth bidirectional hanging ring (44) in the second expansion bend (22) is damaged due to being lifted away, thereby completing the removal of the second expansion bend (22).

7. The method according to claim 6, characterized in that In step D, the underwater robot connects the first two-way hanging ring (41) and the second two-way hanging ring (42) together through a hook, and connects the third two-way hanging ring (43) and the fourth two-way hanging ring (44) together through a hook, and the previously damaged steel cable is repaired to form a traction steel cable.

8. The method according to claim 7, characterized in that The step E comprises the following steps: Step E1: a cable laying work vessel is pre-stationed near the second offshore platform (B), the cable laying work vessel is loaded with cables, the cleaning ball (40) on the traction steel cable is removed, and the cable is docked with one end of the traction steel cable from which the cleaning ball (40) is removed; Step E2: Start the winch on the pulling construction ship to pull and recover the traction steel cable. Pull the traction steel cable at the end of the traction steel cable where no cable is passed through, so that the cable passes through the second connecting riser (12) in turn, enters the abandoned and sealed marine oil and gas pipeline (100), and finally comes out of the first connecting riser (11), until the cable reaches the pulling construction ship parked near the first marine platform (A).

9. The method according to claim 8, characterized in that Also includes: Step F: A first concrete bundling (31) and a second concrete bundling (32) are respectively placed on the exposed sections of the submarine cable (200) between the two ends of the abandoned and sealed marine oil and gas pipeline (100) and the first marine platform (A) and the second marine platform (B) for protection.

10. The method according to claim 9, characterized in that The first concrete row (31) and the second concrete row (32) are both row assemblies composed of concrete test blocks.

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