Mooring system suitable for dry tree cylinder platform, dry tree oil extraction system and design method

Abstract

The invention provides a mooring system suitable for a trunk tree cylinder platform, a trunk tree oil extraction system and a design method, the mooring system comprises m * n mooring cables, m is the number of groups of the mooring cables and is larger than or equal to 3, n is the number of each group of mooring cables and is larger than or equal to 2, the top ends of the m groups of mooring cables are distributed in the circumferential direction of the trunk tree cylinder platform, and every two adjacent groups of mooring cables are arranged at the interval of 360 / m degrees; every two adjacent mooring cables in each set of mooring cables are arranged at the interval of 2-8 degrees, the bottom ends of the mooring cables are connected with the seabed, the connecting line between the top ends and the bottom ends of the mooring cables passes through the central axis of the trunk tree cylinder platform, and the mooring radius of the mooring cables is smaller than or equal to 1200 meters. According to the mooring system suitable for the dry tree cylinder platform, the multiple sets of mooring cables are evenly arranged in the circumferential direction of the dry tree cylinder platform, it can be guaranteed that the maximum horizontal offset of the dry tree cylinder platform in all directions is close, and the mode that a single mooring cable is adopted in the prior art is changed into the mode that multiple mooring cables are arranged in each set; and the cost of the mooring rope is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of marine engineering, and in particular to a mooring system suitable for a dry tree cylinder platform, a dry tree oil production system and a design method. Background Art

[0002] At present, in order to exploit the oil and gas in the deep sea, it is usually necessary to build an oil and gas production platform on the surface of the deep sea, which integrates deep-sea drilling, oil and gas processing, oil storage, oil unloading, power generation, heating and living functions, and then transport the oil and natural gas to oil tankers or oil or gas tanks on land through pipelines. The oil and gas production platform is generally suspended on the surface of the deep sea. In order to drill in the deep sea and transport the drilled oil and gas, the current mainstream deep-sea oil and gas field development solutions mainly include semi-submersible platforms with column support structures, floating production storage and offloading units (FPSO), SPAR and tension leg platforms. These production platforms have different economic and technical applicability for different sea conditions and different stages of oil field development.

[0003] The dry tree cylindrical platform has a simple structure. Compared with the ship-type FPSO, it has high oil storage efficiency per unit steel and low construction cost. It has no single-point device and does not require a turret structure. It has low maintenance costs in the later stage. It has no wind direction requirements and is insensitive to the direction of environmental loads. It has a high deck bearing capacity and small fatigue load caused by waves. The dry tree oil production technology places the oil production equipment on a floating platform, which is convenient for the control and operation of oil production. The equipment cost is lower and it is very suitable for the secondary development of isolated oil fields and marginal oil fields that have reached the middle and late stages of development.

[0004] The Ganshu oil production technology requires that the floating platform has a small motion amplitude, especially the heave, which places high demands on the mooring system of the cylindrical platform. For sea areas with large wave heights, high flow velocities and frequent typhoons, the floating platform will have large heave and offset, affecting the Ganshu oil production equipment. At present, in order to ensure the motion performance of the floating platform, a larger mooring radius is generally used while ensuring that the tension meets the requirements. The cost of a single mooring cable of a gravity mooring with a conventional anchor chain-steel cable structure is relatively expensive, which will lead to a significant increase in the construction cost of the mooring system. In order to meet the motion performance of the Ganshu cylindrical floating platform and effectively control the cost of the mooring system, the design of the mooring system faces great challenges. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a mooring system, a dry tree oil production system and a design method suitable for a dry tree cylinder platform, aiming to solve the problem in the related art that in order to meet the requirement of small motion amplitude of the dry tree cylinder platform, a single mooring cable with a large mooring radius and high cost is used, resulting in a significant increase in the construction cost of the mooring system.

[0006] The present invention provides a mooring system suitable for a trunk tree cylindrical platform, comprising m×n mooring cables, wherein m is the number of groups of the mooring cables, and m≥3, n is the number of mooring cables in each group, and n≥2, the top ends of the m groups of mooring cables are distributed around the circumference of the trunk tree cylindrical platform, and two adjacent groups of mooring cables are arranged at an interval of 360 / m degrees, two adjacent mooring cables in each group of mooring cables are arranged at an interval of 2-8 degrees, the bottom ends of the mooring cables are connected to the seabed, and the connecting line between the top ends and the bottom ends of the mooring cables passes through the central axis of the trunk tree cylindrical platform, and the mooring radius of the mooring cables is less than or equal to 1200 meters.

[0007] According to the mooring system suitable for the trunk tree cylinder platform provided by the present invention, the mooring cable includes an upper anchor chain, an upper installation chain, a steel cable, a lower installation chain and a lower anchor chain connected in sequence, an end of the upper anchor chain away from the upper installation chain is used to be connected to the trunk tree cylinder platform, and an end of the lower anchor chain away from the lower installation chain is used to be connected to the seabed.

[0008] According to the mooring system suitable for the trunk tree cylinder platform provided by the present invention, the upper anchor chain is connected to the trunk tree cylinder platform through a platform chain, and the platform chain is connected to the upper anchor chain through the upper and lower fairlead holes of the trunk tree cylinder platform in turn.

[0009] According to the mooring system suitable for the trunk tree cylinder platform provided by the present invention, the upper fairlead is arranged at the outer edge of the main deck of the trunk tree cylinder platform, and the lower fairlead is arranged at the outer edge of the heave plate of the trunk tree cylinder platform.

[0010] According to the mooring system suitable for the dry tree cylinder platform provided by the present invention, m=4 and n=4.

[0011] According to the mooring system suitable for the trunk tree cylinder platform provided by the present invention, two adjacent groups of mooring cables are arranged at an interval of 90 degrees, and the interval between two adjacent mooring cables in each group of mooring cables is 4 degrees.

[0012] The present invention also provides a dry tree oil production system, comprising a dry tree cylinder platform and the mooring system suitable for the dry tree cylinder platform as described above.

[0013] The present invention also provides a design method for a mooring system suitable for a trunk tree cylinder platform, which is used to design a mooring system suitable for the trunk tree cylinder platform as described above, and the design method comprises: Based on the environmental data of the target sea area, the number of mooring cables is determined to be m×n, where m is the number of groups of mooring cables and n is the number of mooring cables contained in each group, and the setting orientation of each group of mooring cables is determined to ensure that the difference of the maximum horizontal deviation of the trunk cylinder platform in each direction is less than a preset value; Based on the geological data of the target sea area, determine the location of the anchor point where the mooring cable is connected to the seabed, and then determine the mooring radius of the mooring system; Determining the component structures of a single mooring cable, the length of each component structure, and the product grade of each component structure based on the mooring radius, the tension and fatigue requirements of the mooring system; The mooring system is analyzed by frequency domain and time domain calculation using calculation software, and the calculation results are evaluated. If the mooring system meets the tension requirements, fatigue requirements, riser stroke requirements, the lifting force at the anchor point is acceptable to the pile foundation professionals, and the mooring cable does not touch the bottom, the mooring system is determined to be reasonably designed. If at least one of the requirements is not met, the length of each component structure of a single mooring cable and the product grade of each component structure are re-determined.

[0014] According to the design method of a mooring system suitable for a trunk tree cylinder platform provided by the present invention, the mooring radius is less than or equal to 1200 meters.

[0015] According to the design method of the mooring system applicable to the dry tree cylinder platform provided by the present invention, the frequency domain-time domain calculation analysis of the mooring system using the calculation software includes: Obtaining the ship class corresponding to the dry tree cylinder platform; Based on the ship class corresponding to the trunk cylinder platform, the applicable safety factor of the mooring cable is selected, and it is analyzed whether each component structure of the mooring cable meets the tension requirement. The safety factor includes the safety factor required by DNV, ABS, CCS or BV classification societies.

[0016] The present invention adopts the above technical solution, which has the following advantages: The mooring system suitable for a trunk tree cylindrical platform provided by the present invention comprises m×n mooring cables, wherein m is the number of groups of mooring cables, and m≥3, n is the number of mooring cables in each group, and n≥2, the top ends of the m groups of mooring cables are distributed around the circumference of the trunk tree cylindrical platform, and two adjacent groups of mooring cables are arranged at an interval of 360 / m degrees, two adjacent mooring cables in each group of mooring cables are arranged at an interval of 2-8 degrees, the bottom ends of the mooring cables are connected to the seabed, and the connecting line between the top and the bottom ends of the mooring cables passes through the central axis of the trunk tree cylindrical platform, and the mooring radius of the mooring cables is less than or equal to 1200 meters. The mooring system applicable to the trunk tree cylinder platform provided by the present invention has multiple groups of mooring cables evenly arranged along the circumference of the trunk tree cylinder platform, which can ensure that the maximum horizontal offset of the trunk tree cylinder platform in all directions is close, and the form of a single mooring cable used in the prior art is changed to a form of multiple mooring cables per group, so that the mooring radius is greatly reduced and controlled within 1200 meters, thereby also reducing the cost of the mooring cable. For sea areas with large wave heights, high flow rates and frequent typhoons, this solution can control the mooring radius within 1200m, and is suitable for water depths of 500m and below. Under the combined action of extreme wind, waves and currents, the offset of the trunk tree cylinder platform can be controlled within 10% of the water depth, and the mooring cable can be guaranteed not to touch the bottom under extreme environmental conditions. The mooring system applicable to the trunk tree cylinder platform provided by the present invention solves the problems of large platform offset amplitude and large mooring radius, and effectively saves construction and procurement costs while improving the operational safety of the trunk tree cylinder platform.

[0017] Furthermore, in the dry tree oil production system provided by the present invention, since the mooring system applicable to the dry tree cylinder platform as described above is provided, it has the same advantages as described above.

[0018] Furthermore, the design method of the mooring system applicable to the dry tree cylinder platform provided by the present invention is used to design the mooring system applicable to the dry tree cylinder platform as described above, so the designed mooring system has the same advantages as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a top view of a mooring system applicable to a dry tree cylinder platform provided by an embodiment of the present invention; Figure 2 is a side view of a mooring system applicable to a dry tree cylinder platform provided by one embodiment of the present invention; Figure 3It is a flow chart of a design method of a mooring system suitable for a dry tree cylinder platform provided by the present invention.

[0021] Reference numerals: 100: mooring rope; 110: upper anchor chain; 120: upper installation chain; 130: steel cable; 140: lower installation chain; 150: lower anchor chain; 200: dry tree cylinder platform. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0024] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is more than two, unless otherwise clearly and specifically defined.

[0025] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0026] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction 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 may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0028] The present invention provides a mooring system suitable for a trunk tree cylinder platform, comprising m×n mooring cables, wherein m is the number of mooring cable groups, and m≥3, n is the number of mooring cables in each group, and n≥2, the top ends of the m groups of mooring cables are distributed around the circumference of the trunk tree cylinder platform, and two adjacent groups of mooring cables are arranged at an interval of 360 / m degrees, and two adjacent mooring cables in each group of mooring cables are arranged at an interval of 2-8 degrees, the bottom ends of the mooring cables are connected to the seabed, and the connecting line between the top and the bottom ends of the mooring cables passes through the central axis of the trunk tree cylinder platform, and the mooring radius of the mooring cables is less than or equal to 1200 meters. The mooring system suitable for the trunk tree cylinder platform provided by the present invention evenly arranges multiple groups of mooring cables along the circumference of the trunk tree cylinder platform, which can ensure that the maximum horizontal offset of the trunk tree cylinder platform in all directions is close, and the form of a single mooring cable in the prior art is changed to a form of multiple mooring cables in each group, thereby shortening the mooring radius and reducing the cost of the mooring cable.

[0029] Combine the following Figure 1 to Figure 2 The present invention discloses a mooring system suitable for a dry tree cylinder platform and a dry tree oil production system.

[0030] An embodiment of the present invention provides a mooring system suitable for a trunk tree cylindrical platform, comprising m×n mooring cables 100, wherein m is the number of groups of mooring cables 100, n is the number of mooring cables 100 in each group of mooring cables 100, and m≥3 and n≥2. The top ends of the m groups of mooring cables 100 are distributed around the circumference of the trunk tree cylindrical platform 200, and the two adjacent groups of mooring cables 100 are arranged at an interval of 360 / m degrees, and the two adjacent mooring cables 100 in each group of mooring cables 100 are arranged at an interval of 2 to 8 degrees. The bottom ends of the mooring cables 100 are connected to the seabed, and the line between the top and bottom ends of the mooring cables 100 passes through the central axis of the trunk tree cylindrical platform 200. In this way, the maximum horizontal offset of the trunk tree cylinder platform 200 in all directions can be ensured to be close, and the form of a single mooring cable 100 used in the prior art is changed to a form of multiple mooring cables 100 per group, which greatly shortens the mooring radius and allows the mooring radius to be controlled within 1,200 meters, thereby reducing the procurement cost of the mooring cable 100.

[0031] The mooring system for the dry tree cylinder platform provided by the present invention can control the mooring radius within 1200m for sea areas with high wave height, high flow velocity and frequent typhoons, and is applicable to water depths of 500m and below. Under the combined action of extreme wind, waves and currents, the offset of the dry tree cylinder platform 200 can be controlled within 10% of the water depth, and the mooring cable 100 is ensured not to touch the bottom under extreme environmental conditions. The mooring system for the dry tree cylinder platform provided by the present invention solves the problems of large platform offset amplitude and large mooring radius, and effectively saves construction and procurement costs while improving the operating safety of the dry tree cylinder platform 200.

[0032] In some embodiments of the present invention, the mooring line 100 includes an upper anchor chain 110, an upper installation chain 120, a steel cable 130, a lower installation chain 140, and a lower anchor chain 150. The top end of the upper anchor chain 110 is used to connect to the dry tree cylinder platform 200, the bottom end of the upper anchor chain 110 is connected to the top end of the steel cable 130 through the upper installation chain 120, the bottom end of the steel cable 130 is connected to the top end of the lower anchor chain 150 through the lower installation chain 140, and the lower anchor chain 150 is connected to the seabed.

[0033] In some embodiments of the present invention, a platform chain is arranged between the upper anchor chain 110 and the trunk tree cylindrical platform 200, the platform chain is connected to the upper cable guide hole and the lower cable guide hole on the trunk tree cylindrical platform 200, and the top end of the upper anchor chain 110 is connected to the platform chain, thereby realizing the connection between the upper anchor chain 110 and the trunk tree cylindrical platform 200.

[0034] In a specific embodiment, the upper fairlead hole is arranged at the outer edge of the main deck of the trunk tree cylinder platform 200 , and the lower fairlead hole is arranged at the outer edge of the heave plate of the trunk tree cylinder platform 200 .

[0035] In a specific embodiment, the mooring system includes 4 groups of mooring cables 100, each group includes 4 mooring cables 100. The interval between two adjacent groups of mooring cables 100 is 90 degrees, and the interval between two adjacent mooring cables 100 in each group is 4 degrees.

[0036] Of course, the number of groups of mooring cables 100 of the mooring system, the angles between groups, and the angles between single mooring cables 100 in the above embodiments are merely exemplary descriptions and do not limit the protection scope of the present application.

[0037] In a specific embodiment, a mooring system suitable for a trunk tree cylinder platform is provided, and the operating water depth of the trunk tree cylinder platform 200 connected by the mooring system is 340 meters. The following table shows the detailed parameters of each component structure thereof.

[0038]

[0039] The mooring system is composed of 5 sections in total. In order to limit the deviation of the trunk cylinder platform 200, the design pre-tension is generally set to 3000KN. The stiffness of the steel cable 130 can be adjusted to match the design pre-tension.

[0040] An embodiment of the present invention further provides a dry tree oil production system, comprising a dry tree drum platform 200 and the mooring system applicable to the dry tree drum platform as described above. Since the mooring system as described above is provided, the system has the same advantages as described above.

[0041] Combine the following Figure 3 The present invention discloses a design method of a mooring system suitable for a dry tree cylinder platform.

[0042] An embodiment of the present invention further provides a design method for a mooring system applicable to a dry tree cylinder platform, which is used to design a mooring system applicable to the dry tree cylinder platform as described above, and the design method comprises the following steps: Step S100, based on the environmental data of the target sea area, determining the number of mooring cables 100 to be m×n, wherein m is the number of groups of mooring cables 100, and n is the number of mooring cables 100 contained in each group, and determining the setting orientation of each group of mooring cables 100 to ensure that the difference of the maximum horizontal deviation of the trunk cylinder platform 200 in each direction is less than a preset value; Step S200: based on the geological data of the target sea area, determine the location of the anchor point where the mooring cable 100 is connected to the seabed, and then determine the mooring radius of the mooring system; Step S300, determining the component structures of a single mooring cable 100, the length of each component structure, and the product grade of each component structure based on the mooring radius, the tension and fatigue requirements of the mooring system; Step S400: Use calculation software to perform frequency domain-time domain calculation analysis on the mooring system, and evaluate the calculation results. If the mooring system meets the tension requirements, fatigue requirements, riser stroke requirements, the lifting force at the anchor point can be accepted by the pile foundation professionals, and the mooring cable 100 does not touch the bottom, it is determined that the mooring system is reasonably designed. If at least one of the requirements is not met, the length of each component structure of the single mooring cable 100 and the product grade of each component structure are re-determined.

[0043] Specifically, for the trunk cylinder platform 200, at least three groups of mooring cables 100 can be provided, and the three groups of mooring cables 100 are evenly distributed along the circumference of the trunk cylinder platform 200, so that the maximum horizontal deviation of the trunk cylinder platform 200 in all directions can be ensured to be close. Each group includes at least two mooring cables 100. Compared with the form of using a single mooring cable 100 in the prior art, dividing a single mooring cable 100 into multiple mooring cables can greatly shorten the mooring radius, thereby greatly reducing the purchase cost of the mooring cable 100.

[0044] Specifically, the mooring cables 100 may be arranged in a 4×4 form, that is, 4 groups of mooring cables 100, with the groups spaced 90 degrees apart, and each group including 4 mooring cables 100, so that the mooring recovery performance in each direction can be ensured to be close.

[0045] The locations of the multiple groups of mooring cables 100 are determined based on the environmental data of the target sea area. The multiple groups of mooring cables 100 are distributed at equal intervals. When the location of one group of mooring cables 100 is known, the locations of the remaining groups of mooring cables 100 can be obtained.

[0046] Further collect marine geological data of the target sea area and determine the location of the anchor point based on the marine geological data. For example, in order to limit the horizontal deviation of the platform and ensure that the mooring tension meets the requirements, combined with the special environmental conditions and geological conditions of the South China Sea, after optimization analysis, the mooring radius of the mooring system with a water depth of 300m-500m can be set within 1200m.

[0047] Based on the above-determined mooring radius, tension and fatigue requirements of the mooring system, a single mooring cable 100 is generally composed of 5 component structures, which mainly include an upper anchor chain 110, an upper installation chain 120, a steel cable 130, a lower installation chain 140 and a lower anchor chain 150.

[0048] The above five parts also need to determine the length and product grade of each component structure respectively.

[0049] When the above data are determined, the frequency domain-time domain calculation and analysis of the preliminarily selected mooring system can be carried out through potential flow analysis commercial software combined with mooring time domain analysis software, such as aqwa, HydroD, Orcaflex or Sima.

[0050] The calculation results are then evaluated, and the evaluation not only needs to consider the tension and fatigue requirements of the mooring system itself and the requirement that the steel cable 130 cannot touch the bottom, but also needs to meet other professional requirements, such as whether the maximum deflection can meet the stroke requirements of the riser and whether the lifting force at the anchor point can be accepted by the pile foundation professional, etc. Based on these requirements, the length and product grade of each component structure in the mooring cable 100 are continuously adjusted until all requirements are met.

[0051] In some embodiments of the present invention, using computing software to perform frequency domain-time domain computing analysis on the mooring system comprises the following steps: Step S410, obtaining the ship class corresponding to the trunk cylinder platform 200; Step S420, based on the ship class corresponding to the trunk cylinder platform 200, select the safety factor applicable to the mooring cable 100, and analyze whether each component structure of the mooring cable 100 meets the tension requirement, and the safety factor includes the safety factor required by DNV, ABS, CCS or BV classification society.

[0052] Specifically, for the trunk tree cylinder platform 200, in the process of analyzing the mooring system, the mooring tension and the maximum deviation of the trunk tree cylinder platform 200 are equally important. The tension analysis needs to fully consider the tension of each section of the mooring cable 100, and meet the safety factor required by classification societies such as DNV, ABS, CCS, and BV to ensure that the tension meets the requirements. The specific requirements in the specification that are applicable depend on which class the platform will eventually enter.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application 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 replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A mooring system suitable for a dry tree cylinder platform, characterized in that: The invention comprises m×n mooring cables (100), wherein m is the number of groups of the mooring cables (100), and m≥3, n is the number of mooring cables (100) in each group, and n≥2, the top ends of the m groups of mooring cables (100) are distributed around the circumference of a trunk tree cylindrical platform (200), and two adjacent groups of mooring cables (100) are arranged at an interval of 360 / m degrees, and two adjacent mooring cables (100) in each group of mooring cables (100) are arranged at an interval of 2 to 8 degrees, the bottom ends of the mooring cables (100) are connected to the seabed, and the line between the top and bottom ends of the mooring cables (100) passes through the central axis of the trunk tree cylindrical platform (200), and the mooring radius of the mooring cables (100) is less than or equal to 1200 meters.

2. The mooring system for a dry tree cylinder platform according to claim 1, characterized in that: The mooring cable (100) comprises an upper anchor chain (110), an upper installation chain (120), a steel cable (130), a lower installation chain (140) and a lower anchor chain (150) connected in sequence, wherein one end of the upper anchor chain (110) away from the upper installation chain (120) is used to connect to the trunk cylinder platform (200), and one end of the lower anchor chain (150) away from the lower installation chain (140) is used to connect to the seabed.

3. The mooring system for a dry tree cylinder platform according to claim 2, characterized in that: The upper anchor chain (110) is connected to the trunk tree cylindrical platform (200) via a platform chain, and the platform chain is connected to the upper anchor chain (110) via an upper cable guide hole and a lower cable guide hole of the trunk tree cylindrical platform (200) in sequence.

4. The mooring system for a dry tree cylinder platform according to claim 3, characterized in that: The upper cable guide hole is arranged at the outer edge of the main deck of the trunk tree cylindrical platform (200), and the lower cable guide hole is arranged at the outer edge of the heave plate of the trunk tree cylindrical platform (200).

5. The mooring system for a dry tree cylinder platform according to any one of claims 1 to 4, characterized in that: m=4 and n=4.

6. The mooring system for a dry tree cylinder platform according to claim 5, characterized in that: Two adjacent groups of mooring cables (100) are arranged at an interval of 90 degrees, and two adjacent mooring cables (100) in each group of mooring cables (100) are arranged at an interval of 4 degrees.

7. A dry tree oil production system, characterized in that: It comprises a trunk tree cylinder platform (200) and a mooring system suitable for the trunk tree cylinder platform as described in any one of claims 1 to 6.

8. A design method for a mooring system suitable for a dry tree cylinder platform, characterized in that: Used for designing a mooring system suitable for a dry tree cylinder platform as claimed in any one of claims 1 to 6, the design method comprising: Based on the environmental data of the target sea area, the number of mooring cables (100) is determined to be m×n, wherein m is the number of groups of the mooring cables (100), and m≥3, n is the number of mooring cables (100) contained in each group, and n is greater than or equal to 2, and the setting orientation of each group of the mooring cables (100) is determined to ensure that the difference in the maximum horizontal offset of the trunk cylinder platform (200) in each direction is less than a preset value; Based on geological data of the target sea area, determining the position of the anchor point where the mooring cable (100) is connected to the seabed, and then determining the mooring radius of the mooring system; Determining the component structures of a single mooring cable (100), the length of each component structure, and the product grade of each component structure based on the mooring radius, the tension and fatigue requirements of the mooring system; The mooring system is subjected to frequency domain-time domain calculation and analysis using calculation software, and the calculation results are evaluated. If the mooring system meets the tension requirements, fatigue requirements, riser stroke requirements, the lifting force at the anchor point can be accepted by the pile foundation professionals, and the mooring cable (100) does not touch the bottom, it is determined that the mooring system is reasonably designed. If at least one of the requirements is not met, the length of each component structure of a single mooring cable (100) and the product grade of each component structure are re-determined.

9. The design method of a mooring system for a dry tree cylinder platform according to claim 8, characterized in that: The mooring radius is less than or equal to 1,200 meters.

10. The design method of a mooring system for a dry tree cylinder platform according to claim 8, characterized in that: The frequency domain-time domain calculation and analysis of the mooring system using the calculation software includes: Obtaining the ship class corresponding to the trunk cylinder platform (200); Based on the ship class corresponding to the trunk cylinder platform (200), a safety factor applicable to the mooring cable (100) is selected, and it is analyzed whether each component structure of the mooring cable (100) meets the tension requirement, wherein the safety factor includes the safety factor required by DNV, ABS, CCS or BV classification societies.

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