Cable-stayed externally-hung platform system of large-span deepwater jacket platform

Abstract

A large-span deepwater jacket platform cable-stayed external hanging platform system comprises a mother platform, an external hanging platform and a cable-stayed connecting system, the cable-stayed connecting system comprises a base, a trestle and a stay cable, and a triangular stable structure is formed by connecting lines or intersection points of extension lines of end points of the base, the stay cable, the external hanging platform and the trestle. By means of a stay cable-trestle composite connection structure, flexible transition and multidirectional load transmission of the structure are achieved, additional stress concentration of the platform is relieved, waves, wind loads and self-weight coupling loads are effectively dispersed under the extreme sea condition, and the structural stability and safety redundancy of the externally-hung platform in the deepwater complex environment are improved. The system remarkably improves the stability and the bearing capacity of the externally-hung platform, solves the problems that platform externally-hung transformation in a medium-deep water area is difficult, and the cost of an independent newly-added platform is high, achieves efficient installation and reliable bearing under the medium-deep water large-span condition, remarkably reduces the externally-hung production increasing cost of a deep-sea oil and gas development platform, and improves the development efficiency of the deep-sea oil and gas development platform. And an economical and efficient solution is provided for marginal oilfield development.

Description

Technical Field

[0001] The present invention relates to offshore oilfield development and ocean engineering technologies, and particularly to a cable-stayed external platform system for a large-span deep-water jacket platform. Background Art

[0002] For shallow-water (<40 m water depth) oilfields, the industry has accumulated mature application experience of external pile leg structures, and can flexibly respond by expanding the deck operation area, setting up external well slots, adding treatment facilities, etc. However, in the medium-deep water area with a water depth of 100 - 300 m, the platform structure is complex and the underwater jacket space is crowded. Traditional external transformation methods are difficult to implement, and independently adding a new platform has high costs and a long cycle, with poor economic benefits.

[0003] Existing offshore oil and gas stable production and increased production technologies are mainly applicable to shallow-water areas. Usually, the deck operation area of the main platform is expanded through external pile leg structures, and measures such as adjusting well position arrangements, adding treatment facilities, and setting internal or close external well slots are combined to achieve production capacity improvement. These technologies have been widely applied to fixed shallow-water platforms and have mature engineering experience and implementation systems. However, for the medium-deep water area with a water depth of 100 - 300 m, there is currently no mature and feasible external type production-increasing platform product and system solution in the industry. The technical system is still in the exploration stage, and there are the following prominent problems and technical gaps: 1. The underwater structure of the medium-deep water jacket platform is much larger than the top deck area. The jacket structure is dense and intertwined complexly, resulting in the need to expand the horizontal distance between the newly added well slot and the existing well slots to more than 50 - 60 m, far exceeding the conventional layout standard of within 15 m in shallow water, and the space layout is extremely limited.

[0004] 2. After the span is significantly increased, the external platform needs to bear greater wave, wind load and platform self-weight effects. The structure is affected by complex coupled loads, and the difficulty of stability and reliability design is significantly improved. The shallow-water technical route is not competent.

[0005] 3. If a newly added independent fixed platform is used for function expansion, a complete jacket and upper module need to be newly built, with huge engineering investment. At the same time, the demolition and recovery costs after the platform is scrapped are extremely high, and the economic benefits are low, making it difficult to meet the cost control requirements of small-scale development of marginal oilfields.

[0006] In summary, the existing external platform technology in shallow-water areas cannot meet the engineering requirements of medium-deep water oilfield development.

[0007] It should be noted that the information disclosed in the above background art section is only used for understanding the background of the present application, and thus may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0008] The main object of the present invention is to overcome the defects existing in the above-mentioned background art, and to provide a cable-stayed external hanging platform system for a large-span deep-water jacket platform.

[0009] To achieve the above object, the present invention adopts the following technical solutions: A cable-stayed external hanging platform system for a large-span deep-water jacket platform, comprising: A mother platform, which includes a fixed jacket and original facilities; An external hanging platform, which is used to carry new facilities; A cable-stayed connection system, which connects the mother platform and the external hanging platform, and includes: A base, fixed on the top of the mother platform, and cable-stayed connection devices are provided on the base; A trestle, one end of which is connected to the mother platform and the other end is connected to the external hanging platform; Cable-stayed cables, which connect the cable-stayed connection devices on the base with the connection points of the external hanging platform; Wherein, the connection points of the base, the cable-stayed cables, the external hanging platform and the endpoints of the trestle or the intersection points of their extension lines form a triangular stable structure.

[0010] Further, the geometric size of the external hanging platform is smaller than that of the mother platform, and the bottom deck of the external hanging platform is at the same horizontal plane as the bottom deck of the mother platform.

[0011] Further, the number of the bases is at least 1, and the number of the trestles is at least two.

[0012] Further, the two trestles are arranged non-parallel with a predetermined included angle, so that the mother platform, the trestles and the external hanging platform form a trapezoidal stable structure in the top view plane.

[0013] Further, the connecting pipe section at one end of the trestle is connected to the main support pipe of the mother platform, and the connecting pipe section at the other end is connected to the main support pipe of the external hanging platform; the structural height of the connecting pipe section on the mother platform side of the trestle is greater than the structural height of the connecting pipe section on the external hanging platform side.

[0014] Further, the number of the cable-stayed cables is at least four, and the cable-stayed cables connect the cable-stayed connection devices on the base with the connection points at the top of the external hanging platform.

[0015] Further, the horizontal position of the connection point of the base and the cable-stayed cable is higher than the horizontal position of the connection point of the trestle and the mother platform.

[0016] Further, the cable-stayed connection devices on the base include mechanical locking devices.

[0017] Further, it further includes a boom, the bottom of the boom is fixedly mounted on the mother platform at an adjustable angle, and a pulley system is provided at the top of the boom; the stay cable passes through the pulley system at the top of the boom and then is connected to the external hanging platform.

[0018] Further, the external hanging platform is a single-layer structure or a multi-layer structure.

[0019] The present invention has the following beneficial effects: The present invention provides a cable-stayed external hanging platform system for a large-span deep-water jacket platform. The cable-stayed external hanging platform system is an economic, efficient, stable, reliable and easy-to-install cable-stayed external hanging production-increasing system for a 100-300-meter-class deep-water fixed platform to increase production. It significantly reduces the construction cost of deep-sea oil and gas development in a deep-sea complex environment, and is beneficial to realizing the reserve increase and production increase of an efficient and economic oil and gas field. This system is connected through a trestle and supported by stay cables, and is externally expanded relying on the original platform structure. Without changing the main structure of the main platform, it effectively improves the operation space and equipment layout ability.

[0020] Aiming at the defect that the traditional shallow-water external hanging pile leg technology cannot adapt to the deep-water large span, the system of the present invention innovatively adopts a cable-stayed cable-trestle composite connection structure. In the system, a triangular stable structure is formed by the base, the stay cable, the external hanging platform and the intersection point of the connecting line of the endpoints of the trestle or its extension line, which significantly improves the stability and bearing capacity of the external hanging platform. The designed "stay cable + trestle" combined connection mechanism realizes the flexible transition of the structure and the multi-directional load transfer, effectively relieves the concentrated additional stress of the platform, and effectively disperses the coupled loads of waves, wind loads and self-weight under extreme sea conditions, significantly improving the structural stability and safety redundancy of the external hanging platform in a deep-sea complex environment, and ensuring the long-term service safety of the system. This design breakthroughly realizes the flexible load transfer between the external hanging platform and the mother platform, which not only avoids the impact of stress concentration on the original platform, but also guarantees the efficient layout space for newly added well slots and other treatment facilities. At the same time, by means of modular prefabrication and stay cable tensioning technology, the on-site installation efficiency and construction adaptability can be significantly improved. In the preferred solution, the mother platform, the trestle and the external hanging platform form a trapezoidal stable structure in the top view plane, further improving the structural stability and reliability of the external hanging platform in a deep-sea complex environment. In the preferred solution, a boom with a pulley system at the top is introduced. The stay cable passes through the pulley system at the top of the boom and then is connected to the external hanging platform, which can dynamically optimize the tension distribution of the stay cable and improve the hoisting safety and structural bearing efficiency of a large-tonnage external hanging platform. The position of the boom can be adjusted according to the space of the mother platform and is not limited to a fixed position, greatly enhancing the feasibility of the system. The present invention can well meet the dual goals of new reserve access and stable production increase of a deep-water fixed platform, and has outstanding advantages such as high stability, strong bearing capacity, rapid deployability, light weight and good economy.

[0021] Other beneficial effects in the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the cable-stayed scheme of the non-boom - single-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0023] Figure 2 It is a schematic diagram of the cable-stayed scheme of the boom - single-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0024] Figure 3 It is a schematic diagram of the cable-stayed scheme of the boom - single-layer external hanging - far-external hanging platform of the base in the embodiment of the present invention.

[0025] Figure 4 It is a schematic diagram of the cable-stayed scheme of the boom - multi-layer external hanging - far-external hanging platform of the base in the embodiment of the present invention.

[0026] Figure 5 It is a schematic diagram of the cable-stayed scheme of the boom - multi-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0027] Figure 6 It is a front view of the cable-stayed scheme of the non-boom - single-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0028] Figure 7 It is a partial side view of the cable-stayed scheme of the non-boom - single-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0029] Figure 8 It is a top view of the cable-stayed scheme of the non-boom - single-layer external hanging - near-external hanging platform of the base in the embodiment of the present invention.

[0030] Figure 9 It is a schematic diagram of the trestle in the embodiment of the present invention.

[0031] Figure 10 It is a schematic diagram of the single-layer external hanging platform in the embodiment of the present invention.

[0032] Reference numerals: 1 - fixed jacket, 2 - mother platform, 3 - base, 4 - cable stay, 5 - external hanging platform, 6 - trestle, 7 - new well slot, 8 - dust-proof plate, 9 - original well slot, 10 - boom, 61 - connecting pipe section at one end of the trestle, 62 - connecting pipe section at the other end of the trestle, 51 - first connection point between the external hanging platform and the cable stay, 52 - second connection point between the external hanging platform and the trestle. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The following provides a detailed description of the embodiments of the present invention. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0034] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. Additionally, the connection can be for a fixing function or for a coupling or communicating function.

[0035] It should be understood that the orientation or positional relationship indicated by terms such as "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention.

[0036] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0037] The present invention aims to overcome the problems that it is difficult to implement the external modification method of the main platform in the medium and deep water area, and the independent addition of a new platform has high costs and a long cycle. It provides an economically efficient, stable and reliable, and easily installed large-span deep-water jacket platform cable-stayed external production increase system for the production increase of 100 - 300-meter-class deep-water fixed platforms.

[0038] Refer to Figures 1 to 8 , an embodiment of the present invention provides a large-span deep-water jacket platform cable-stayed external platform system, including a mother platform 2, an external platform 5, and a cable-stayed connection system. The mother platform 2 includes a fixed jacket 1 and original facilities such as an original well slot 9. The external platform 5 is used to carry new facilities. The cable-stayed connection system connects the mother platform 2 and the external platform 5. The cable-stayed connection system includes: a base 3, fixed to the top of the mother platform 2, on which there is a cable-stayed cable connection device; a trestle 6, one end of which is connected to the mother platform 2, and the other end is connected to the external platform 5 through a second connection point 52; a cable-stayed cable 4, connected between the cable-stayed cable connection device on the base 3 and a first connection point 51 of the external platform 5; wherein, the base 3, the cable-stayed cable 4, the external platform 5, and the intersection point of the endpoint connection line or its extension line of the trestle 6 form a triangular stable structure.

[0039] In some embodiments, the geometric size of the external hanging platform 5 is smaller than that of the mother platform 2, and the bottom deck of the external hanging platform 5 is at the same horizontal plane as the bottom deck of the mother platform 2.

[0040] In some embodiments, the number of the bases 3 is at least 1, and the number of the trestles 6 is at least two.

[0041] Refer to Figures 1 to 6 , in some embodiments, the horizontal position of the connection point between the base 3 and the stay cable 4 is higher than the horizontal position of the connection point between the trestle 6 and the mother platform 2. The position of the base 3 on the top of the mother platform 2 can be adjusted according to actual space requirements.

[0042] In some embodiments, the stay cable connection device on the base 3 may include a mechanical locking device.

[0043] Refer to Figure 8 , in some embodiments, the two trestles 6 are arranged non-parallelly with a predetermined included angle, so that the mother platform 2, the trestles 6 and the external hanging platform 5 form a trapezoidal stable structure in the top view plane.

[0044] Refer to Figure 9 , in some embodiments, one end connecting pipe section 61 of the trestle 6 is connected to the main support pipe of the mother platform 2, and the other end connecting pipe section 62 is connected to the main support pipe of the external hanging platform 5; the structural height of the mother platform side connecting pipe section 61 of the trestle 6 is greater than the structural height of the external hanging platform side connecting pipe section 62. It should be understood that the connection can be a weld connection formed by various welding methods. Of course, in addition to welding, it can also be achieved by other operations such as mechanical connection, bolt connection, hinge connection and internal penetration to achieve the same effect as welding.

[0045] In some embodiments, the number of the stay cables 4 is at least four, and the stay cables 4 connect the stay cable connection devices on the base 3 to the first connection points 51 at the top of the external hanging platform 5.

[0046] In some embodiments, the large-span deep-water jacket platform stay cable type external hanging platform system further includes a jib 10. The bottom of the jib 10 is fixedly mounted on the mother platform 2 at an adjustable angle, and a pulley system is provided at the top of the jib 10. The stay cable 4 passes through the pulley system at the top of the jib 10 and then is connected to the external hanging platform 5.

[0047] In some embodiments, the external hanging platform 5 is a single-layer structure (see Figure 1 , Figure 2 , Figure 3 , Figure 6 , Figure 7 , Figure 8 andFigure 10 ). In other embodiments, the external platform 5 may also be a multi-layer structure, such as a double-layer structure (see Figure 4 and Figure 5 ).

[0048] Refer to Figures 1 to 6 , in some embodiments, the new facilities carried by the external platform 5 may include a new well slot 7. A dust-proof plate 8 may be installed at the bottom end of the new well slot 7.

[0049] The system of the present invention utilizes the above-mentioned cable-stayed bridge composite connection structure to achieve flexible structural transition and multi-directional load transfer, effectively relieve the concentrated additional stress of the platform, and can effectively disperse the coupled loads of waves, wind loads and self-weight under extreme sea conditions, significantly improving the structural stability and safety redundancy of the external platform in deep-water complex environments. This system can significantly improve the stability and bearing capacity of the external platform, solve the problems of difficult external transformation of platforms in medium and deep water areas in the past and high cost of independent new platforms, realize efficient installation and reliable bearing under the conditions of large spans in medium and deep water, and significantly reduce the cost of external production increase of deep-sea oil and gas development platforms.

[0050] The following further describes specific embodiments of the present invention and their implementation principles.

[0051] A cable-stayed external platform system for a large-span deep-water jacket platform mainly includes a mother platform, a cable-stayed connection system and one or more external platforms. The mother platform 2 includes a fixed jacket 1. The geometric size of the external platform 5 is smaller than that of the mother platform 2, and the bottom deck of the external platform 5 is on the same horizontal line as the bottom deck of the mother platform 2 and is not lower than the sea level. The cable-stayed connection system includes several cable-stayed cables 4, several trestles 6, a base 3 and other optional equipment (such as a jib 10). The connection system includes more than one base 3, more than two trestles 6 and more than four cable-stayed cables 4 connected, as Figures 1 to 8 shown. In the front view, the intersection of the connecting lines of the endpoints of the sub-parts of the connection system or the extension line of its structure forms a triangular stable shape. In the top view, the trestle 6, the mother platform 2 and the external platform 5 form a trapezoidal stable shape. In the connection system, the trestle 6 is connected to the mother platform 2 and the external platform 5 by welding or other forms, as Figures 1 to 8 shown. In the connection system, the base 3 can be arranged at any position on the premise of ensuring that the horizontal position of the connection point of the cable-stayed cable 4 is higher than the horizontal position of the trestle 6 and the actual requirements. The cable-stayed cable 4 connection device on the base 3 can have a mechanical locking mechanism in addition to a lifting system to maintain the long-term service condition of the cable-stayed cable 4.

[0052] The overall structure of the cable-stayed external platform system for a large-span deep-water jacket platform is as Figure 1As shown in the figure. The external hanging platform solution includes the original fixing device, the connection system and the external hanging platform system. This external hanging platform solution adopts the form of long-span stay cables, fully considering the reasonable layout and safety of the structure.

[0053] Among them, the original fixing device includes the fixed jacket 1, the mother platform 2, and the original well slot 9, all of which are existing fixed facilities for oil and gas production.

[0054] The connection system includes the base 3, the trestle 6, multiple stay cables 4, and the jib 10. The base 3 is fixed on the top of the mother platform, and has a lifting system on it to realize the tension adjustment and mechanical locking function of the stay cables; the trestle 6 connects the external hanging platform 5 and the mother platform 2, one end is connected to the main support steel pipe of the mother platform, and the other end is connected to the main support steel pipe of the external hanging platform 5; the multiple stay cables connect the top of the external hanging platform and the base. The jib 10 is used to adjust the angle of the stay cables to improve the lifting capacity of the base and the stay cables. The jib 10 is used when the external hanging platform has a large weight. The bottom of the jib 10 is fixed on the mother platform 2 and has an angle adjustment function, and the top has a pulley system, as Figures 2 to 5 shown.

[0055] The external hanging platform system includes the external hanging platform 5, the new well slot 7 and the dust-proof plate 8. The top of the external hanging platform has multiple stay cable connection points and is connected to the base through multiple stay cables. The main support steel pipe of the external hanging platform is connected to the mother platform 2 through the trestle 6. The new well slot 7 is installed on the external hanging platform, and its installation and production methods are the same as or similar to those of the original well slot 9. The dust-proof plate 8 is installed at the bottom end of the new well slot 7.

[0056] The trestle 6 is connected to the mother platform 2 and the external hanging platform by welded fixed connections. The platform system is connected by two trestles 6, and the two trestles 6 are arranged non-parallelly, that is, the mother platform 2, the trestle 6, and the external hanging platform 5 are arranged in a trapezoid to enhance the structural stability.

[0057] The number of the multiple stay cables 4 in the schematic diagram is only for illustration, and the actual number of roots is based on ensuring the safety and reliability of the project. The material of the stay cables needs to meet the requirements of high strength and corrosion resistance (including necessary anti-corrosion measures such as coating and electrochemistry), and the fatigue caused by wind and wave loads and the vibration of platform machinery and equipment needs to be considered. The position of the base 3 in the external hanging platform system is a standard schematic diagram, and the actual size can be adjusted according to the actual space of the mother platform, as Figures 2 to 5 shown.

[0058] The stay cable type external hanging platform system of the large-span deep-water jacket platform in this embodiment is a new system for the expansion of fixed offshore structures. It can expand the fixed offshore oil and gas production platform, greatly increase the oil and gas production, and create considerable economic benefits on the premise of ensuring safety and reliability.

[0059] During implementation, first, based on theoretical calculations, the shape and weight of the external hanging platform allowed by the scheme are determined. On the premise of meeting the requirements of stable and increased production, a single-layer structure external hanging platform can be preferentially considered, and then a double-layer structure external hanging platform can be considered. As Figures 1 to 3 shown, the external hanging platform is of a single-layer structure, Figure 4 and Figure 5 shown, the external hanging platform is of a double-layer structure. Taking the single-layer structure external hanging platform 5 shown in Figure 10 as an example, it is first built in an onshore factory and then transported to a designated offshore location. As Figure 10 shown, the top of the external hanging platform 5 is designed with a first connection point 51 for the stay cable, and the side facing the mother platform is designed with a second connection point 52 for the trestle. The connection system in the present invention has various derivative layout forms, specifically referring to that the position of the base 3 can be changed according to the actual deck space of the mother platform 2, such as Figure 1 , Figure 2 , Figure 5 shown, the two bases 3 are arranged on the side close to the external hanging platform, such as Figure 3 and Figure 4 shown, the two bases 3 are arranged on the side far from the external hanging platform 5. In addition, it is not limited to the above two forms, and any position combination can be considered. The boom 10 in the connection system, the common form is such as the A-type structure, with angle adjustment and mechanical locking functions at the bottom, and the top and intermediate links should meet the requirements for the arrangement of multiple stay cables, such as Figures 2 to 5 shown. The boom 10 structure plays a role in adjusting the angle of the stay cable and improving the lifting capacity.

[0060] Taking the single-layer external hanging platform - without boom form in Figure 1 as an example, it includes two trestles 6 at a certain angle (as Figure 8 shown). The trestles adopt a steel pipe frame structure, and all pipe ends are welded. In order to better match with the platforms on both sides, one end connecting pipe section 61 and the other end connecting pipe section 62 of the trestle 6 are designed with different heights (as Figure 9 shown). The two trestles are arranged in a trapezoidal hypotenuse layout and are welded together, and need to bear the wind and wave loads from the marine environment. As Figure 6 shown, there is a height difference between the trestle 6 and the base 3, so as to ensure that the base, stay cable, external hanging platform and trestle present a triangular structure and ensure the stability of the structure. As Figure 7 shown in the front view, each base 3 contains (at least) two stay cable lifting devices, and multiple stay cables cross the reel and are connected to the preset devices at the top of the external hanging platform.

[0061] The installation operations of the long-span cable-stayed external hanging platform system are as follows: Before the installation operation process of the long-span cable-stayed external hanging platform system, first investigate the geological conditions around the fixed platform to identify the location of the new wellhead. Then, based on the existing facilities layout of the mother platform, plan the position and height of the foundation, and conduct theoretical calculations to determine the maximum weight of the external hanging platform. The installation operations of the long-span cable-stayed external hanging platform system include: (1) onshore manufacturing and transportation; (2) hoisting operation; (3) welding operation; (4) pre-tensioning and fixing of the cable-stayed cables.

[0062] (1) Onshore manufacturing: Design and process the external hanging platform and the trestle in an onshore factory. The trestle and the external hanging platform are welded together at a certain angle on land, and then transported to the designated area.

[0063] (2) Hoisting operation: Connect the cable-stayed cable 4 to the external hanging platform 5, and use the hoisting equipment on the tugboat to lift the combined body of the external hanging platform 5 and the trestle 6. The above two hoisting equipment cooperate with each other to lift the combined body to the appropriate position.

[0064] (3) Welding and pre-tensioning: Adopt temporary fixing methods, such as ropes, to ensure the relative position between the trestle 6 and the mother platform 2. Weld the other end of the trestle 6 to the mother platform 2. During the welding process, pay attention to the change of the cable-stayed cable tension to prevent the combined body from shaking due to being too loose and the internal force of the combined body from concentrating due to being too tight, thus affecting the welding effect.

[0065] (4) Pre-tensioning and fixing of the cable-stayed cables: After welding, remove the hoisting equipment on the tugboat. Adjust the lifting system on the foundation 3 in real time. When the cable-stayed cable tension reaches the preset value, enable the mechanical locking device in the lifting system to reduce the risk of failure of the lifting equipment due to long-term high-load work.

[0066] Compared with the traditional technology, the significant advantages of the present invention are reflected in the following aspects: 1. Overcome the difficulty of layout expansion of well slots in medium-depth platforms Due to the complex underwater structure of the jacket platform in waters with a depth of 100 - 300 meters, the distance between the new well slot and the original well slot far exceeds the design standard of shallow platforms, and the layout space of the conventional external hanging structure is severely limited. The present invention breakthroughly provides a structural solution with the ability to arrange well slots with a large span.

[0067] 2. Solve the stability problem of the external hanging platform under large-span conditions The structure response of the traditional external hanging platform is unstable when facing large spans and complex sea conditions, and the coupling of its own weight and ocean loads is significant. The present invention improves the stability and bearing capacity of the external hanging platform through the cable-stayed cable structure to ensure the long-term service safety of the system.

[0068] 3. Solve the problem of flexible connection between the external hanging platform and the main platform The existing connection methods cannot balance the requirements of large span, small node displacement, and reliable connection. The "cable-stayed + trestle" combined connection mechanism designed in the present invention realizes the flexible transition of the structure and multi-directional load transfer, effectively alleviating the additional stress concentration on the platform.

[0069] 4. Solve the problem that the existing shallow water outboard technology cannot be applied to deep water The outboard pile leg structure used in shallow water areas is limited by the structural length and installation process and cannot be extended to medium and deep water areas. The cable-stayed outboard platform of the present invention provides a new structural logic for medium and deep water development, breaking through the adaptation boundary of shallow water technology.

[0070] 5. Solve the problem of low construction and installation efficiency of the outboard platform The traditional fixed platform has a long construction period and complex installation steps, especially with high risks in the deep water environment. The present invention can utilize modular prefabrication and cable-stayed tensioning technology to improve the on-site installation efficiency and construction adaptability.

[0071] 6. Solve the problems of high cost and difficult abandonment of the new fixed platform solution Constructing a new independent fixed platform not only has high costs and a long cycle, but also faces high environmental and economic costs during later decommissioning. The system of the present invention relies on the existing platform structure, can be recycled and disassembled, and has good life cycle economy.

[0072] 7. Solve the problem of poor economic efficiency in marginal oilfield development Marginal oilfield development has a small scale and a short cycle, with extremely high requirements for the economy of facilities. The outboard platform system of the present invention has a lightweight structure, flexible deployment, and can be expanded as needed, adapting to the development scenarios of small-scale and high-benefit marginal oilfields.

[0073] The beneficial effects of the embodiments of the present invention specifically further include: 1. The present invention designs a cable-stayed outboard platform system for a large-span deepwater jacket platform. Compared with the traditional 40-meter shallow water outboard well slot facility, by introducing the concept of cable-stayed cables, on the premise of ensuring safety and reliability, the platform area and the number of new well slots are significantly increased, greatly improving the output of existing oilfields and having huge potential economic value.

[0074] 2. In the present invention, the structural layout fully considers structural stability. The number of bases is at least two, the number of trestles is at least two, and the trestles are arranged in a trapezoidal hypotenuse shape. There is a height difference between the base and the trestle to form a triangular stability. After the installation operation is completed, the lifting system fixes the cable-stayed cables through a mechanical locking device, effectively reducing the risk of long-term high-load operation of the crane. Multiple cable-stayed cables are respectively connected to the top of the outboard platform and are made of high-strength and highly corrosion-resistant materials. Even when one cable-stayed cable fails, the remaining cable-stayed cables can still maintain the stability of the outboard platform without overturning, having sufficient safety redundancy.

[0075] 3. The system proposed by the present invention meets the long-term production requirements of offshore oil and gas platforms. For the deep-water environment of 100 - 300 meters, the solution of the present invention meets the production increase requirements and new reserve requirements of offshore marginal oilfields.

[0076] 4. The system proposed by the present invention has extremely strong adaptability and can be adjusted according to specific platforms and marine environments. The position of the base and the boom scheme are adjusted according to the space of the mother platform, not limited to a fixed position, greatly enhancing the feasibility of the system.

[0077] 5. In addition to meeting the production maintenance of the new well slots, the external platform of the present invention can add many auxiliary devices such as storage and processing facilities according to specific needs when necessary, improving the crude oil production capacity of the platform.

[0078] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments. It cannot be determined that the specific implementation of the present invention is only limited to these descriptions. For those of ordinary skill in the technical field to which the present invention belongs, without departing from the concept of the present invention, they can make several substitutions or modifications to these described embodiments, and these substitution or modification methods should all be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description with reference to terms such as "an embodiment", "some embodiments", "preferred embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. Without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made herein without departing from the protection scope of the patent application.

Claims

1. A cable-stayed external hanging platform system for a large-span deep-water jacket platform, characterized in that Comprising: A mother platform, which includes a fixed jacket and original facilities; An external hanging platform, which is used to carry additional facilities; A cable-stayed connection system, which connects the mother platform and the external hanging platform, and includes: A pedestal, fixed to the top of the mother platform, and cable-stayed connection devices are provided on the pedestal; A trestle, one end of which is connected to the mother platform and the other end is connected to the external hanging platform; Cable-stayed cables, which connect the cable-stayed connection devices on the pedestal to the connection points of the external hanging platform; Wherein, the connection points of the pedestal, the cable-stayed cables, the external hanging platform and the endpoints of the trestle or the intersection points of their extension lines form a triangular stable structure.

2. The cable-stayed external platform system of the long-span deep-water jacket platform according to claim 1, characterized in that, The geometric size of the external hanging platform is smaller than that of the mother platform, and the bottom deck of the external hanging platform is at the same horizontal plane as the bottom deck of the mother platform.

3. The cable-stayed externally hung platform system of the long-span deep-water jacket platform according to claim 1 or 2, wherein The number of the pedestals is at least 1, and the number of the trestles is at least two.

4. The cable-stayed externally suspended platform system of the long-span deep-water jacket platform according to claim 3, characterized in that, The two trestles are arranged non-parallel with a predetermined included angle, so that the mother platform, the trestles and the external hanging platform form a trapezoidal stable structure in the top view plane.

5. The cable-stayed externally suspended platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that One end connecting pipe section of the trestle is connected to the main support pipe of the mother platform, and the other end connecting pipe section is connected to the main support pipe of the external hanging platform; the structural height of the connecting pipe section on the mother platform side of the trestle is greater than the structural height of the connecting pipe section on the external hanging platform side.

6. The cable-stayed external hanging platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that The number of the cable-stayed cables is at least four, and the cable-stayed cables connect the cable-stayed connection devices on the pedestal to the connection points at the top of the external hanging platform.

7. The cable-stayed external hanging platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that, The horizontal position of the connection point of the pedestal and the cable-stayed cable is higher than the horizontal position of the connection point of the trestle and the mother platform.

8. The cable-stayed externally suspended platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that The cable-stayed connection devices on the pedestal include mechanical locking devices.

9. The cable-stayed externally hung platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that It further includes a jib, the bottom of the jib is adjustably fixed to the mother platform, and a pulley system is provided at the top of the jib; the cable-stayed cable passes through the pulley system at the top of the jib and then is connected to the external hanging platform.

10. The cable-stayed externally hung platform system of the long-span deep-water jacket platform according to claim 1 or 2, characterized in that, The external hanging platform is a single-layer structure or a multi-layer structure.

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