A large-span deepwater jacket platform with an inclined-stayed external platform system

Abstract

A cable-stayed external platform system for a large-span deepwater jacket platform comprises a mother platform, an external platform, and a cable-stayed connection system. The cable-stayed connection system includes a base, a trestle, and cable stays. The triangular structure formed by the intersection of the base, cable stays, external platform, and trestle endpoints, and the cable-stayed-trestle composite connection structure achieves flexible structural transitions and multi-directional load transfer, alleviating additional stress concentration on the platform. It effectively disperses the coupled loads of waves, wind, and deadweight in extreme sea conditions, enhancing the external platform's structural stability and safety redundancy in complex deepwater environments. The system significantly improves the external platform's stability and load-bearing capacity, addressing the difficulties of platform externalization modification in medium- and deepwater areas and the high cost of adding independent platforms. It enables efficient installation and reliable load-bearing in medium- and deepwater conditions over large spans, significantly reducing the cost of increasing production from external platforms in deepwater oil and gas development platforms, and providing a cost-effective solution for marginal oilfield development.

Description

Technical Field

[0001] The present invention relates to offshore oilfield development and marine engineering technology, and in particular to a large-span deepwater jacket platform oblique-stayed external platform system. Background Art

[0002] For shallow-water oilfields (less than 40 meters in depth), the industry has accumulated mature experience in the application of external pile-leg structures, allowing for flexible adaptation through expanding deck operating areas, installing external well slots, and adding processing facilities. However, in medium- to deep-water areas (100 to 300 meters in depth), the platform structure is complex and the space for underwater jackets is crowded, making traditional external pile-leg modification difficult to implement. Adding a separate platform is also costly and time-consuming, with poor economic benefits.

[0003] Existing offshore oil and gas production stabilization and production increase technologies are mainly applicable to shallow water areas. They often expand the main platform deck operating area through external pile leg structures, and cooperate with measures such as adjusting well layout, adding processing facilities, and setting up internal or close-range external well slots to achieve production capacity improvement. These technologies have been widely used on fixed shallow water platforms and have mature engineering experience and implementation systems. However, for medium and deep water areas with a water depth of 100 to 300 meters, there are currently no mature and feasible external production increase platform products and system solutions in the industry. The technical system is still in the exploratory stage, and there are the following outstanding problems and technical gaps:

[0004] 1. The underwater structure of a mid- to deep-water jacket platform is much larger than the top deck area. The jacket structure is dense and complex, requiring the horizontal distance between new well slots and existing ones to be extended to more than 50 to 60 meters, far exceeding the conventional shallow-water layout standard of less than 15 meters. This severely limits the space for layout.

[0005] 2. With the significant increase in span, the external platform needs to withstand greater wave and wind loads and the platform's own weight. The structure faces the influence of complex coupled loads, and the difficulty of stability and reliability design increases significantly. The shallow water technology route is not competent.

[0006] 3. If a new independent fixed platform is used for functional expansion, a complete jacket and topsides must be newly constructed, which requires a huge investment. Furthermore, the cost of dismantling and recycling the platform after it is scrapped is high, resulting in low economic benefits and making it difficult to meet the cost control requirements of small-scale development of marginal oil fields.

[0007] In summary, the existing external platform technology in shallow water areas cannot meet the engineering requirements of medium and deep water oilfield development.

[0008] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0009] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a large-span deep-water jacket platform inclined-stayed external platform system.

[0010] To achieve the above object, the present invention adopts the following technical solutions:

[0011] A large-span deepwater jacket platform inclined-stayed external platform system, comprising:

[0012] The mother platform, which contains the fixed jacket and primary facilities;

[0013] External platform, which is used to carry new facilities;

[0014] A diagonal connection system connects the mother platform and the external platform and includes:

[0015] A base is fixed to the top of the mother platform, and a stay cable connection device is provided on the base;

[0016] a trestle, one end of which is connected to the mother platform and the other end of which is connected to the external platform;

[0017] A stay cable connecting the stay cable connection device on the base and a connection point of the external platform;

[0018] Wherein, the intersection of the end points of the base, the inclined cable, the external platform and the pier or their extended lines forms a triangular stable structure.

[0019] Furthermore, the geometric dimensions of the external platform are smaller than those of the mother platform, and the bottom deck of the external platform and the bottom deck of the mother platform are on the same horizontal plane.

[0020] Furthermore, the number of the bases is at least one, and the number of the piers is at least two.

[0021] Furthermore, the two trestles are arranged non-parallel with a predetermined angle, so that the mother platform, the trestles and the external platform form a trapezoidal stable structure when viewed from above.

[0022] Furthermore, one end connecting pipe section of the pier 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 platform; the structural height of the connecting pipe section on the mother platform side of the pier is greater than the structural height of the connecting pipe section on the external platform side.

[0023] Furthermore, the number of the stay cables is at least four, and the stay cables connect the stay cable connection device on the base and the connection point on the top of the external platform.

[0024] Furthermore, the horizontal position of the connection point between the base and the inclined cable is higher than the horizontal position of the connection point between the pier and the mother platform.

[0025] Furthermore, the stay cable connection device on the base includes a mechanical locking device.

[0026] Furthermore, it also includes a boom, the bottom of which is fixed on the mother platform at an adjustable angle, and the top of the boom is provided with a pulley system; the inclined cable passes through the pulley system on the top of the boom and is connected to the external platform.

[0027] Furthermore, the external platform is a single-layer structure or a multi-layer structure.

[0028] The present invention has the following beneficial effects:

[0029] This invention proposes a cable-stayed external platform system for a large-span deepwater jacket platform. This system provides an economical, efficient, stable, reliable, and easy-to-install solution for increasing production from fixed platforms in deepwater depths of 100 to 300 meters. This significantly reduces construction costs for deepwater oil and gas development in complex deepwater environments, facilitating efficient and economical reserve and production increases in oil and gas fields. The system utilizes trestle connections and cable-stayed support, allowing for external expansion within the existing platform structure. This effectively increases working space and equipment layout capabilities without altering the main platform structure.

[0030] In response to the defect that traditional shallow-water external pile leg technology cannot adapt to large spans in deep water, the system of the present invention innovatively adopts a cable-stayed-bridge composite connection architecture. The system uses the intersection of the base, cable-stayed cables, external platform and trestle end points or their extension lines to form a triangular stable structure, which significantly improves the stability and carrying capacity of the external platform. The designed "cable-stayed cable + trestle" joint connection mechanism realizes structural flexible transition and multi-directional load transfer, effectively alleviates the additional stress concentration of the platform, and effectively disperses the wave, wind load and deadweight coupling load under extreme sea conditions, significantly improving the structural stability and safety redundancy of the external platform in complex deep-water environments, ensuring the long-term service safety of the system. This design has achieved a breakthrough in the flexible load transfer between the external platform and the mother platform, which not only avoids the impact of stress concentration on the original platform, but also ensures the efficient layout space of new wellbore and other processing facilities. At the same time, with the help of modular prefabrication and cable-stayed tensioning technology, the on-site installation efficiency and construction adaptability can also be significantly improved. In the preferred solution, the mother platform, the pier and the external platform form a trapezoidal stable structure when viewed from above, further improving the structural stability and reliability of the external platform in complex deep-water environments. In the preferred solution, a boom with a pulley system on the top is introduced, and the inclined cable passes through the pulley system on the top of the boom and is connected to the external platform. This can dynamically optimize the tension distribution of the inclined cable and improve the hoisting safety and structural load-bearing efficiency of the large-tonnage external platform. The position of the boom can be adjusted with the space of the mother platform and is not limited to a fixed position, which greatly enhances the feasibility of the system. The present invention can well meet the dual goals of new reserve access and stable production and increased production for deep-water fixed platforms, and has outstanding advantages such as high stability, strong load-bearing capacity, rapid deployment, lightweight structure, and good economy.

[0031] Other beneficial effects of the embodiments of the present invention will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of a cable-stayed scheme of a platform with no boom, a single-layer external hanging, and a base close to the external hanging, according to an embodiment of the present invention.

[0033] Figure 2 It is a schematic diagram of an inclined-stayed scheme with a boom, a single-layer external hanging, and a base close to the external hanging platform according to an embodiment of the present invention.

[0034] Figure 3 It is a schematic diagram of an inclined-stayed scheme with a boom, a single-layer external hanging, and a base remote external hanging platform according to an embodiment of the present invention.

[0035] Figure 4 It is a schematic diagram of an inclined-stayed scheme with a boom, multi-layer external hanging, and a base remote external hanging platform according to an embodiment of the present invention.

[0036] Figure 5 It is a schematic diagram of an inclined-stayed scheme with a boom, multi-layer external hangings, and a base close to the external hanging platform according to an embodiment of the present invention.

[0037] Figure 6 It is a front view of a cable-stayed solution of a platform with no boom, a single-layer external hanger, and a base close to the external hanger in an embodiment of the present invention.

[0038] Figure 7 It is a partial side view of the inclined-stayed scheme of no boom, single-layer external hanging, and base close to the external hanging platform in an embodiment of the present invention.

[0039] Figure 8 It is a top view of the inclined-stayed scheme of the embodiment of the present invention, which has no boom, a single-layer external hanging, and a base close to the external hanging platform.

[0040] Figure 9 2 is a schematic diagram of a trestle according to an embodiment of the present invention.

[0041] Figure 10 Schematic diagram of a single-layer plug-in platform according to an embodiment of the present invention.

[0042] Figure numerals: 1-fixed jacket, 2-mother platform, 3-base, 4-stayed cable, 5-external platform, 6-trestle, 7-new well slot, 8-dustproof plate, 9-original well slot, 10-jib, 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 platform and the stay cable, 52-second connection point between the external platform and the trestle. DETAILED DESCRIPTION

[0043] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0044] 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. In addition, connection can be used for both fixing and coupling or communication.

[0045] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0047] The present invention aims to overcome the problems of difficult implementation of external plug-in modification of the main platform in medium-deep water areas and the high cost and long cycle of adding independent platforms. It provides an economical, efficient, stable, reliable and easy-to-install large-span deep-water jacket platform inclined external plug-in production increase system for increasing production of fixed platforms in deep waters of 100 to 300 meters.

[0048] See Figures 1 to 8 An embodiment of the present invention provides a long-span deepwater jacket platform inclined-stayed external platform system, comprising a mother platform 2, an external platform 5, and an inclined-stayed connection system. The mother platform 2 comprises a fixed jacket 1 and original facilities such as an original wellbore 9. The external platform 5 is used to carry newly added facilities. The inclined-stayed connection system connects the mother platform 2 and the external platform 5. The inclined-stayed connection system comprises: a base 3 fixed to the top of the mother platform 2, on which is provided an inclined 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 via a second connection point 52; an inclined cable 4, which is connected between the inclined cable connection device on the base 3 and the first connection point 51 of the external platform 5; wherein the intersection of the end points of the base 3, the inclined cable 4, the external platform 5, and the trestle 6 or their extended lines forms a triangular stable structure.

[0049] In some embodiments, the geometric dimensions of the external platform 5 are smaller than those of the mother platform 2 , and the bottom deck of the external platform 5 and the bottom deck of the mother platform 2 are on the same horizontal plane.

[0050] In some embodiments, the number of the bases 3 is at least one, and the number of the piers 6 is at least two.

[0051] See Figures 1 to 6 In some embodiments, the horizontal position of the connection point between the base 3 and the inclined 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.

[0052] In some embodiments, the stay cable connection device on the base 3 may include a mechanical locking device.

[0053] See Figure 8In some embodiments, the two piers 6 are arranged non-parallel with a predetermined angle, so that the mother platform 2, the pier 6 and the external platform 5 form a trapezoidal stable structure in a top view.

[0054] See Figure 9 In some embodiments, a connecting pipe section 61 at one end of the trestle 6 is connected to the main support pipe of the mother platform 2, and a connecting pipe section 62 at the other end is connected to the main support pipe of the external platform 5. The structural height of the connecting pipe section 61 on the mother platform side of the trestle 6 is greater than the structural height of the connecting pipe section 62 on the external platform side. It should be understood that the connection can be a weld connection formed by various welding methods. Of course, in addition to welding, other methods such as mechanical connection, bolt connection, hinge connection, and internal penetration can also achieve an equivalent effect to welding.

[0055] In some embodiments, the number of the stay cables 4 is at least four, and the stay cables 4 connect the stay cable connection device on the base 3 and the first connection point 51 on the top of the external platform 5 .

[0056] In some embodiments, the large-span deepwater jacket platform cable-stayed external platform system further includes a boom 10, the bottom of which is fixed to the mother platform 2 at an adjustable angle, and a pulley system is provided at the top of the boom 10. The stay cable 4 passes through the pulley system at the top of the boom 10 and is then connected to the external platform 5.

[0057] In some embodiments, the external platform 5 is a single-layer structure (see Figure 1 、 Figure 2 、 Figure 3 、 Figure 6 、 Figure 7 、 Figure 8 and Figure 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 ).

[0058] See Figures 1 to 6 In some embodiments, the newly added facilities carried by the external platform 5 may include a new well trough 7. A dustproof plate 8 may be installed at the bottom of the new well trough 7.

[0059] The system of the present invention utilizes the aforementioned cable-stayed-bridge composite connection architecture to achieve flexible structural transitions and multi-directional load transfer, effectively alleviating additional stress concentration on the platform. It can effectively disperse the coupled loads of waves, wind, and deadweight in extreme sea conditions, significantly enhancing the structural stability and safety redundancy of the externally mounted platform in complex deepwater environments. This system can significantly improve the stability and load-bearing capacity of the externally mounted platform, and address the previous difficulties in retrofitting externally mounted platforms in medium- and deepwater areas and the high cost of adding independent new platforms. It enables efficient installation and reliable load-bearing in medium- and deepwater areas over large spans, significantly reducing the cost of externally mounted production increases for deepwater oil and gas development platforms.

[0060] The following further describes specific embodiments of the present invention and their implementation principles.

[0061] A cable-stayed external platform system for a large-span deepwater 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 external platform 5 is smaller in geometric size than 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, not lower than the sea level. The cable-stayed connection system includes several cable stays 4, several trestles 6, a base 3 and other optional equipment (such as a boom 10). The connection system includes one or more bases 3, two or more trestles 6 and four or more cable stays 4, such as Figures 1 to 8 As shown. In the front view, the intersection of the end lines connecting the sub-parts of the system or their structural extension lines 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 means, such as Figures 1 to 8 As shown in the figure, the base 3 of the connection system can be positioned anywhere, provided that the horizontal position of the cable 4 connection point is above that of the trestle 6 and meets actual requirements. The cable 4 connection device on the base 3, in addition to a lifting system, also features a mechanical locking mechanism to maintain the long-term serviceability of the cable 4.

[0062] The overall structure of the large-span deepwater jacket platform cable-stayed external platform system is as follows: Figure 1 The external platform solution includes the original fixing device, connection system, and external platform system. This external platform solution adopts a large-span cable-stayed structure, fully considering the rational layout and safety of the structure.

[0063] The original fixed devices include a fixed jacket 1, a mother platform 2, and an original well slot 9, all of which are existing fixed oil and gas production facilities.

[0064] The connection system includes a base 3, a trestle 6, a plurality of inclined cables 4, and a boom 10. The base 3 is fixed to the top of the mother platform, and has a lifting system on it to realize the tension adjustment and mechanical locking function of the inclined cables; the trestle 6 connects the external platform 5 and the mother platform 2, one end of which 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 platform 5; the plurality of inclined cables connect the top of the external platform and the base. The boom 10 is used to adjust the angle of the inclined cables and improve the lifting capacity of the base and the inclined cables. The boom 10 is used when a heavy external platform is used. The bottom of the boom 10 is fixed on the mother platform 2 and has an angle adjustment function, and the top has a pulley system, such as Figures 2 to 5 shown.

[0065] The external platform system includes an external platform 5, a new well trough 7, and a dust shield 8. The external platform has multiple cable connection points on its top, connecting it to the base via multiple cables. The external platform's main support steel pipes are connected to the mother platform 2 via a trestle 6. The new well trough 7 is installed on the external platform using the same or similar installation and production methods as the original well trough 9. The dust shield 8 is installed at the bottom of the new well trough 7.

[0066] The platform system is connected by two trestles 6, which are arranged in a non-parallel manner, that is, the mother platform 2, the trestles 6 and the external platform 5 are arranged in a trapezoidal shape to enhance structural stability.

[0067] The number of the multiple stay cables 4 in the diagram is for reference only. The actual number is based on the premise of ensuring the safety and reliability of the project. The cable material must be high-strength and corrosion-resistant (including necessary anti-corrosion measures such as coating and electrochemical treatment), and must take into account the fatigue caused by wind and wave loads and vibration of platform equipment. The position of the base 3 in the external platform system is a standard diagram. The actual size can be adjusted according to the actual space of the mother platform, such as Figures 2 to 5 shown.

[0068] The large-span deepwater jacket platform cable-stayed external platform system of this embodiment is a new system for the expansion of fixed offshore structures. It can expand fixed offshore oil and gas production platforms while ensuring safety and reliability, significantly increasing oil and gas production and creating considerable economic benefits.

[0069] During implementation, first, the shape and weight of the external platform allowed by the plan should be calculated based on theory. Under the premise of meeting the demand for stable production and increased production, the external platform with a single-layer structure can be given priority, followed by the external platform with a double-layer structure. Figures 1 to 3 The external platform shown is a single-layer structure. Figure 4 and Figure 5 The external platform shown is a double-layer structure. Figure 10Taking the single-layer external platform 5 as an example, it is first built in an onshore factory and then transported to a designated location at sea. Figure 10 As shown, the top of the external platform 5 is designed with a first connection point 51 with the inclined cable, and the side facing the mother platform is designed with a second connection point 52 with the pier. The connection system in the present invention has a variety of derivative arrangements, specifically 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 The two bases 3 are arranged on one side close to the external platform, as shown in FIG. Figure 3 and Figure 4 The two bases 3 are arranged on the side away from the external platform 5. In addition, it is not limited to the above two forms and any position combination can be considered. The so-called boom 10 in the connection system is commonly in the form of an A-type structure, with angle adjustment and mechanical locking functions at the bottom, and the top and middle links should meet the requirements of multiple inclined cable arrangements, such as Figures 2 to 5 The boom 10 structure is used to adjust the angle of the inclined cable and improve the lifting capacity.

[0070] by Figure 1 For example, the single-layer external platform without a boom includes two trestles 6 at a certain angle (such as Figure 8 As shown in FIG), the trestle adopts a steel pipe frame structure, and all pipe ends are connected by welding. In order to better match the platforms on both sides, the connecting pipe section 61 at one end of the trestle and the connecting pipe section 62 at the other end are designed to be of different heights (such as Figure 9 As shown). The two piers are arranged in a trapezoidal oblique pattern and are welded together, and need to withstand wind and wave loads from the marine environment. Figure 6 As shown, there is a height difference between the trestle 6 and the base 3, so as to ensure that the base, the inclined cable, the external platform and the trestle present a triangular structure, thereby ensuring the stability of the structure. Figure 7 As shown in the front view, each base 3 contains (at least) two inclined cables 4 lifting equipment, and multiple inclined cables cross the reels and are connected to the preset device on the top of the external platform.

[0071] The installation process of the large-span cable-stayed external platform system is as follows: Before the installation process of the large-span cable-stayed external platform system, the geological conditions around the fixed platform are first investigated to determine the location of the new wellhead. Then, based on the existing facility layout of the mother platform, the base position and height are planned, and theoretical calculations are carried out to determine the maximum weight of the external platform. The installation process of the large-span cable-stayed external platform system includes: (1) onshore manufacturing and transportation; (2) hoisting operations; (3) welding operations; and (4) pre-tensioning and fixing of the cable stays.

[0072] (1) Onshore manufacturing: The external platform and trestle are designed and processed in an onshore factory. The trestle and external platform are installed on land at a certain angle and welded together, and then transported to the designated area.

[0073] (2) Hoisting operation: Connect the inclined cable 4 and the external platform 5, and use the hoisting equipment on the tugboat to lift the combination of the external platform 5 and the pier 6. The above two hoisting equipment cooperate with each other to lift the combination to a suitable position.

[0074] (3) Welding and pre-tensioning: Use a temporary fixing method, such as a rope, to ensure the relative position between the trestle 6 and the mother platform 2, and weld the other end of the trestle 6 to the mother platform 2. During the welding process, attention should be paid to the changes in the tension of the inclined cable to prevent the assembly from shaking due to being too loose, and from being concentrated inside the assembly due to being too tight, thereby affecting the welding effect.

[0075] (4) Pre-tensioning and fixing of the inclined cable: After welding is completed, the lifting equipment on the tugboat is removed, and the lifting system on the base 3 is adjusted in real time. When the tension of the inclined cable reaches the preset value, the mechanical locking device in the lifting system is activated to reduce the risk of failure of the lifting equipment due to long-term high-load operation.

[0076] Compared with traditional technologies, the significant advantages of this invention are embodied in the following aspects:

[0077] 1. Overcoming the difficulties in slot expansion layout on mid- to deep-water platforms

[0078] Due to the complex underwater structure of the jacket platform in water depths of 100 to 300 meters, the distance between the newly added well slots and the original well slots far exceeds the design standards for shallow water platforms, and the space for arranging conventional external structures is severely limited. The present invention provides a breakthrough structural solution capable of arranging large-span well slots.

[0079] 2. Solve the stability problem of the external platform under long span conditions

[0080] Traditional external platforms experience structural instability when exposed to large spans and complex sea conditions, with significant coupling between their own weight and ocean loads. This invention utilizes a stay-cable structure to enhance the stability and load-bearing capacity of the external platform, ensuring the long-term operational safety of the system.

[0081] 3. Solve the problem of flexible connection between the plug-in platform and the main platform

[0082] The existing connection method cannot take into account the requirements of large span, small node displacement and reliable connection. The "cable + trestle" combined connection mechanism designed in this invention realizes structural flexible transition and multi-directional load transfer, effectively alleviating the additional stress concentration on the platform.

[0083] 4. Solve the problem that existing shallow water plug-in technology cannot be applied to deep water

[0084] The external pile leg structure used in shallow waters is limited by its length and installation process, making it difficult to expand to medium- and deep-water areas. The cable-stayed external platform of this invention provides a new structural logic for medium- and deep-water development, breaking through the technical limitations of shallow waters.

[0085] 5. Solve the problem of low efficiency in the construction and installation of external platforms

[0086] Traditional fixed platforms have long construction periods and complex installation steps, especially in deepwater environments, which poses high risks. This invention utilizes modular prefabrication and cable-stayed tensioning technology to improve on-site installation efficiency and construction adaptability.

[0087] 6. Solve the problem of high cost and difficult disposal of new fixed platform solutions

[0088] Building a new independent fixed platform is not only costly and time-consuming, but also faces high environmental and economic costs when scrapped later. The system of the present invention relies on the existing platform structure, is recyclable and disassembled, and has good life cycle economics.

[0089] 7. Poor economics of developing marginal oil fields

[0090] Marginal oilfield development is small-scale and short-term, placing high demands on facility economics. The plug-in platform system of the present invention is lightweight, flexible in deployment, and scalable on demand, making it suitable for small-scale, high-efficiency marginal oilfield development scenarios.

[0091] The beneficial effects of the embodiments of the present invention also include:

[0092] 1. The present invention designs a large-span deepwater jacket platform cable-stayed external platform system. Compared with the traditional 40-meter shallow-water external well slot facilities, by introducing the concept of cable stays, it significantly expands the platform area and the number of newly added well slots while ensuring safety and reliability, greatly improving the production of existing oil fields and having huge potential economic value.

[0093] 2. The structural layout of this invention fully considers structural stability. There are at least two bases and at least two trestles, and the trestles are arranged in a trapezoidal, hypotenuse shape. The height difference between the base and the trestles creates a stable triangle. After installation, the lifting system secures the stay cables with a mechanical locking device, effectively reducing the risk of long-term high-load operation of the crane. Multiple stay cables are connected to the top of the external platform and are made of high-strength, highly corrosion-resistant materials. Even if one cable fails, the remaining cables can still maintain the stability of the external platform and prevent it from capsizing, providing sufficient safety redundancy.

[0094] 3. The system proposed by the present invention meets the long-term production needs of offshore oil and gas platforms. Targeting deepwater environments of 100 to 300 meters, the solution of the present invention meets the production increase needs and new reserve requirements of offshore marginal oil fields.

[0095] 4. The system proposed in this invention is highly adaptable and can be adjusted according to the specific platform and marine environment. The base position and boom design can be adjusted according to the space of the mother platform, not limited to a fixed position, which greatly enhances the feasibility of the system.

[0096] 5. In addition to meeting the production and maintenance needs of newly added well slots, the external platform of the present invention can also add a variety of auxiliary equipment, such as storage and processing facilities, according to specific needs when necessary to improve the platform's crude oil production capacity.

[0097] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A large-span deepwater jacket platform inclined-stayed external platform system, characterized in that: include: The mother platform, which contains the fixed jacket and primary facilities; External platform, which is used to carry new facilities; A diagonal connection system connects the mother platform and the external platform and includes: A base is fixed to the top of the mother platform, and a stay cable connection device is provided on the base; a trestle, one end of which is connected to the mother platform and the other end of which is connected to the external platform; A stay cable connecting the stay cable connection device on the base and a connection point of the external platform; Among them, the number of the bases is at least 1, the number of the piers is at least two, the horizontal position of the connection point between the base and the inclined cable is higher than the horizontal position of the connection point between the pier and the mother platform, and the intersection of the connection line of the end points of the base, the inclined cable, the external platform and the pier or their extended lines forms a triangular stable structure.

2. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1, characterized in that: The geometric dimensions of the external platform are smaller than those of the mother platform, and the bottom deck of the external platform and the bottom deck of the mother platform are on the same horizontal plane.

3. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: The two trestles are arranged non-parallel with a predetermined angle, so that the mother platform, the trestles and the external platform form a trapezoidal stable structure when viewed from above.

4. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: One end connecting pipe section of the pier 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 platform; the structural height of the connecting pipe section on the mother platform side of the pier is greater than the structural height of the connecting pipe section on the external platform side.

5. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: The number of the stay cables is at least four, and the stay cables connect the stay cable connection device on the base and the connection point on the top of the external platform.

6. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: The stay cable connection device on the base includes a mechanical locking device.

7. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: It also includes a boom, the bottom of which is fixed on the mother platform at an adjustable angle, and the top of the boom is provided with a pulley system; the inclined cable passes through the pulley system on the top of the boom and is connected to the external platform.

8. The large-span deepwater jacket platform oblique-stayed external platform system according to claim 1 or 2, characterized in that: The external platform is a single-layer structure or a multi-layer structure.

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