Tuned mass damping device for cylindrical FPSO

Abstract

The invention discloses a tuned mass damping device for a cylindrical FPSO (floating production storage and offloading), and belongs to the technical field of damping shock absorption, the tuned mass damping device comprises an FPSO main body, an annular sleeve and a damper, the annular sleeve is arranged on the outer side of the FPSO main body, the damper is arranged between the FPSO main body and the annular sleeve, the FPSO main body comprises a platform moon pool, a conical heaving plate and a first hanging lug, and the first hanging lug is arranged on the platform moon pool. The conical heaving plate is arranged below the platform moon pool, and the first hanging lug is arranged above the conical heaving plate. According to the tuned mass damping device for the cylindrical FPSO, the waterplane width of the whole structure can be increased, and therefore the swinging motion of the FPSO body is further restrained.

Description

Technical Field

[0001] The present invention relates to the technical field of damping and vibration reduction, in particular to a tuned mass damping device for a cylindrical FPSO. Background Art

[0002] The cylindrical floating production, storage and offloading (FPSO) vessel, due to its rotationally symmetrical design, possesses excellent isotropic hydrodynamic performance and is insensitive to environmental loads from various directions in terms of its swinging freedom. Therefore, this structure is suitable for mooring systems with low technical difficulty and low cost, thereby improving overall economic efficiency. Furthermore, its large oil storage capacity, simple design, and short construction cycle make it particularly suitable for the development of small or marginal oil fields. In recent years, cylindrical FPSOs have been widely used in offshore oil and gas development due to these advantages.

[0003] However, due to its cylindrical structure, FPSOs experience more intense vertical motion, posing a potential threat to the safety of drilling and oil production operations. This can also exacerbate structural fatigue damage and affect long-term service performance. Therefore, effective measures are urgently needed to suppress the vertical motion of cylindrical FPSOs, thereby improving their operational stability and safety. Summary of the Invention

[0004] The object of the present invention is to provide a tuned mass damping device for a cylindrical FPSO to solve the problems mentioned in the background art.

[0005] To achieve the above-mentioned objectives, the present invention provides a tuned mass damping device for a cylindrical FPSO, comprising an FPSO body, an annular sleeve and a damper, wherein the annular sleeve is arranged on the outside of the FPSO body, and the damper is arranged between the FPSO body and the annular sleeve. The FPSO body comprises a platform moon pool, a conical heave plate and a first hanging ear, wherein the conical heave plate is arranged below the platform moon pool, and the first hanging ear is arranged above the conical heave plate.

[0006] Preferably, the annular sleeve includes an inner shell, an upper shell, an outer shell and a bottom shell, the upper shell and the bottom shell are respectively arranged at the top and bottom ends of the inner shell, and the inner shell and the outer shell are arranged between the upper shell and the bottom shell.

[0007] Preferably, the internal space of the annular sleeve is divided by twelve vertically arranged main partitions to form twelve independent compartments, each of which is provided with three vertical and radially arranged transverse control bulkheads and one vertical and perpendicular radially arranged longitudinal control bulkhead.

[0008] Preferably, the transverse sweep bulkhead and the longitudinal sweep bulkhead are provided with water holes at the bottom and the middle respectively, and a ballast pump is arranged at the bottom of each cabin.

[0009] Preferably, a second hanging ear is arranged on the inner shell.

[0010] Preferably, the first hanging lug is provided in twelve groups, and the number of the second hanging lug is the same as that of the first hanging lug.

[0011] Preferably, both ends of the damper are connected to the FPSO body and the annular sleeve respectively through the first hanging ear and the second hanging ear.

[0012] Preferably, the damper includes an outer shell tube and a push rod arranged at one end of the outer shell tube, the bottom of the outer shell tube is hingedly connected to the first hanging ear through bolt one; the top of the push rod is hingedly connected to the second hanging ear through bolt two.

[0013] Preferably, a hydraulic chamber and a lubrication chamber are sequentially provided inside the outer shell, and the push rod passes through the lubrication chamber and the hydraulic chamber in sequence along the geometric center axis of the outer shell, and the end of the push rod in the hydraulic chamber is connected to a piston, and the piston is slidably arranged in the hydraulic chamber.

[0014] Preferably, the piston is provided with a plurality of through holes, a damping spring is provided at one end of the piston, sealing gaskets are provided at both ends of the lubrication cavity, and the sealing gaskets are both sleeved on the push rod.

[0015] Therefore, the present invention adopts the above-mentioned tuned mass damping device for cylindrical FPSO, which has the following beneficial effects:

[0016] (1) Through the resonance principle, an additional tuned mass damping device is used to absorb the energy of vertical movement, thereby reducing the vertical disturbance force of the FPSO body. The device can regulate the system mass through ballast water and adjust the natural frequency of the system according to the wave period to absorb the wave frequency energy in a targeted manner and slow down the vertical movement of the FPSO body.

[0017] (2) This device can increase the waterline width of the overall structure, thereby further suppressing the swaying motion of the FPSO body; each compartment can further increase the oil storage capacity of the FPSO.

[0018] (3) The device is detachable and can be installed on an existing cylindrical FPSO platform without the need to redesign the main body of the FPSO platform.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of a tuned mass damping device for a cylindrical FPSO according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic structural diagram of an annular sleeve according to an embodiment of the present invention;

[0022] Figure 3 A top view of an annular sleeve according to an embodiment of the present invention;

[0023] Figure 4 is a connection diagram of a damper according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the structure of a damper according to an embodiment of the present invention;

[0025] Reference numerals

[0026] 1. FPSO body; 1-1. Platform moon pool; 1-2. Conical heave plate; 1-3. Hanging ear 1; 1-3B. Bolt 1; 2. Annular sleeve; 2-1A. Inner outer shell; 2-1B. Upper outer shell; 2-1C. Outer outer shell; 2-1D. Bottom outer shell; 2-3. Main bulkhead; 2-4. Transverse sweep bulkhead; 2-5. Longitudinal sweep bulkhead; 2-6. Water hole; 2-7. Ballast pump; 2-8. Hanging ear 2; 2-8B. Bolt 2; 3. Damper; 3-1. Outer shell; 3-1A. Hydraulic chamber; 3-1B. Lubrication chamber; 3-2. Push rod; 3-3. Sealing gasket; 3-4. Shock-absorbing spring; 3-5. Piston. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0029] Example:

[0030] like Figure 1-5 As shown, the present invention provides a tuned mass damping device for a cylindrical FPSO, comprising an FPSO body 1 , an annular sleeve 2 and a damper 3 , wherein the damper 3 is arranged between the FPSO body 1 and the annular sleeve 2 .

[0031] The FPSO body 1 comprises a platform moonpool 1-1, a conical heave plate 1-2, and hanging lugs 1-3. The conical heave plate 1-2 is positioned below the platform moonpool 1-1, and hanging lugs 1-3 are positioned above the conical heave plate 1-2. In this embodiment, twelve sets of dampers 3 are evenly arranged around the FPSO body 1. Consequently, twelve sets of hanging lugs 1-3 are also positioned on the conical heave plate 1-2, and twelve sets of hanging lugs 2-8 are also positioned on the annular sleeve 2.

[0032] In this embodiment, an annular sleeve 2 is located outside the FPSO body 1, and a corresponding number of lugs 2-8 are attached to the inside of the annular sleeve 2. The damper 3 is connected to the FPSO body 1 and annular sleeve 2 at both ends via lugs 1-3 and lugs 2-8, respectively. This connection is a free-hinged connection, allowing the annular sleeve 2 to be coaxial with the FPSO body 1 and vertical movement along its central axis. Because each damper 3 connection is a free-hinged bolt connection, only one degree of rotational freedom is retained. Therefore, when more than two dampers 3 are installed, the annular sleeve 2 cannot rotate relative to the FPSO body 1. Increasing the number of dampers 3 can strengthen the restriction on the freedom of movement of the annular sleeve 2.

[0033] like Figure 2As shown, the annular sleeve 2 includes an inner shell 2-1A, an upper shell 2-1B, an outer shell 2-1C and a bottom shell 2-1D. The upper shell 2-1B and the bottom shell 2-1D are respectively arranged at the top and bottom ends of the inner shell 2-1A, and the inner shell 2-1A and the outer shell 2-1C are arranged between the upper shell 2-1B and the bottom shell 2-1D. The inner shell 2-1A, the upper shell 2-1B, the outer shell 2-1C and the bottom shell 2-1D form a watertight hollow annular structure at the bottom; the internal space of the annular sleeve 2 is divided by twelve vertically arranged main bulkheads 2-3 to form twelve independent cabins; each cabin is arranged with three vertical and radially arranged transverse sweep bulkheads 2-4 and one vertical and perpendicular radially arranged longitudinal sweep bulkhead 2-5. Water holes 2-6 are provided at the bottom and the middle of the transverse control bulkhead 2-4 and the longitudinal control bulkhead 2-5, respectively, to reduce the sloshing effect of the ballast water in the cabin when the annular sleeve 2 moves, and to enhance the hydrodynamic performance of the annular sleeve 2. A ballast pump 2-7 is arranged at the bottom of the cabin as the only path for each cabin to exchange with seawater. The ballast pump 2-7 is in a closed state when the device is working normally. When the device needs to change the target wave frequency according to environmental conditions, the ballast pump 2-7 is turned on to change the volume of ballast water in the cabin, thereby regulating the overall mass of the annular sleeve 2, thereby changing the natural frequency of the device, and the ballast pump 2-7 is turned off when the target frequency is reached. Due to the relative independence of the cabins in the annular sleeve 2, some of the cabins can be selected as oil storage tanks, and the remaining cabins still retain their ballast control capabilities, and can also achieve the natural frequency control function. Two lugs 2-8 are arranged on the inner shell 2-1A according to the connection position; such as Figure 3 As shown, the main partition 2-3 is arranged in the same radial direction as the second lug 2-8, and the main partition 2-3 can play a local reinforcement role at the position of the second lug 2-8. The arrangement spacing of the main partition 2-3 can be determined by the number n of the second lug 2-8 to be α = 360° / n.

[0034] In this embodiment, the connection method of the damper 3 is as follows: Figure 4 As shown, the damper 3 includes an outer shell tube 3-1 and a push rod 3-2 arranged at one end of the outer shell tube. The outer shell tube 3-1 is freely hinged to the hanging ear 1-3 through a bolt 1-3B; the push rod 3-2 is freely hinged to the hanging ear 2-8 through a bolt 2-8B.

[0035] In this embodiment, the specific structure of the damper 3 is as follows: Figure 5As shown. The outer shell 3-1 is provided with two chambers, a hydraulic chamber 3-1A and a lubrication chamber 3-1B, in sequence. A push rod 3-2 passes through the lubrication chamber 3-1B and the hydraulic chamber 3-1A along the geometric center axis of the outer shell 3-1. The push rod 3-2 is connected to a piston 3-5 at its distal end within the hydraulic chamber 3-1A. The piston 3-5 can only slide along the axial direction within the hydraulic chamber 3-1A. The piston 3-5 is provided with a plurality of through-holes 3-6, ensuring that when the piston 3-5 reciprocates within the hydraulic chamber 3-1A, the liquid in the chambers on both sides of the piston 3-5 can and only can flow through the holes 3-6, thereby achieving a damping effect. A damping spring 3-4 is provided at one end of the piston 3-5 and is connected to the inner wall of the hydraulic chamber 3-1A via the damping spring 3-4. Sealing pads 3-3 are located at both ends of the lubrication chamber 3-1B, respectively sleeved on the push rod 3-2, to prevent air from entering the chamber and liquid from flowing out of the chamber, respectively.

[0036] Working Principle: After the damper 3 is installed, the damping ratio of the device cannot be changed. Therefore, the total weight of the tuned mass damping device needs to be adjusted to the mass required for the target frequency ratio through ballast pump 2-7. The center of gravity of the system is also adjusted to the axis through ballast pump 2-7. After completion, the ballast pump 2-7 is turned off and the annular sleeve 2 is allowed to reach a balanced state. Based on the principle of resonance tuning, when the wave frequency is consistent with the heave frequency of the FPSO body 1, the demand for heave suppression is the highest. The target tuning frequency can be determined to be within the range of 0.9-1.1 times the natural frequency of the FPSO body 1. The direct restoring force stiffness of the water body on the device is calculated based on the waterplane area of the annular sleeve 2. The total weight of the annular sleeve 2 after ballasting is determined to be within the range of 0.05-0.1 times the mass of the FPSO body. Considering the damping ratio of 0.05-0.2, it is expected that 30-60% heave motion suppression can be achieved. When the device encounters waves of the target frequency, annular sleeve 2 only produces heave motion relative to FPSO body 1. Due to the presence of damper 3, the heave motion of annular sleeve 2 will generate a damping force on FPSO body 1 in the vertical direction with the same frequency as the wave force, but with different phase and amplitude. Therefore, through the rational design and arrangement of damper 3, the vertical wave force can be offset to a certain extent, thereby slowing the heave motion of the FPSO. At the same time, annular sleeve 2 increases the waterline area of the entire structure, indirectly enhancing the stability of FPSO body 1 and reducing its response in the swing degree of freedom.

[0037] Therefore, the present invention adopts the above-mentioned tuned mass damping device for cylindrical FPSO, which can adjust the overall mass of the annular sleeve through ballast water, thereby changing the natural frequency of the system to accurately correspond to the wave frequency in the environmental load.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solutions of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A tuned mass damping device for a cylindrical FPSO, characterized by: The FPSO comprises an FPSO body, an annular sleeve and a damper, wherein the annular sleeve is arranged outside the FPSO body, and the damper is arranged between the FPSO body and the annular sleeve. The FPSO body comprises a platform moon pool, a conical heave plate and a first hanging ear, wherein the conical heave plate is arranged below the platform moon pool, and the first hanging ear is arranged above the conical heave plate.

2. A tuned mass damping device for a cylindrical FPSO according to claim 1, characterized in that: The annular sleeve includes an inner shell, an upper shell, an outer shell and a bottom shell, the upper shell and the bottom shell are respectively arranged at the top and bottom ends of the inner shell, and the inner shell and the outer shell are arranged between the upper shell and the bottom shell.

3. The tuned mass damping device for a cylindrical FPSO according to claim 2, characterized in that: The internal space of the annular sleeve is divided by twelve vertically arranged main partitions to form twelve independent compartments, each of which is provided with three vertical and radially arranged transverse sweep bulkheads and one vertical and perpendicular radially arranged longitudinal sweep bulkhead.

4. The tuned mass damping device for a cylindrical FPSO according to claim 3, characterized in that: The transverse and longitudinal sweep bulkheads are provided with water holes at the bottom and the middle respectively, and a ballast pump is arranged at the bottom of each compartment.

5. The tuned mass damping device for a cylindrical FPSO according to claim 4, characterized in that: A second hanging ear is arranged on the inner shell.

6. The tuned mass damping device for a cylindrical FPSO according to claim 5, characterized in that: The first hanging ears are provided in twelve groups, and the number of the second hanging ears is the same as that of the first hanging ears.

7. The tuned mass damping device for a cylindrical FPSO according to claim 6, characterized in that: The two ends of the damper are connected to the FPSO body and the annular sleeve respectively through the first hanging ear and the second hanging ear.

8. The tuned mass damping device for a cylindrical FPSO according to claim 7, characterized in that: The damper includes an outer shell tube and a push rod arranged at one end of the outer shell tube. The bottom of the outer shell tube is hingedly connected to the first hanging ear through a first bolt; the top of the push rod is hingedly connected to the second hanging ear through a second bolt.

9. The tuned mass damping device for a cylindrical FPSO according to claim 8, characterized in that: A hydraulic chamber and a lubrication chamber are sequentially provided inside the outer shell, and the push rod passes through the lubrication chamber and the hydraulic chamber in sequence along the geometric center axis of the outer shell, and the end of the push rod in the hydraulic chamber is connected to a piston, and the piston is slidably provided in the hydraulic chamber.

10. The tuned mass damping device for a cylindrical FPSO according to claim 9, characterized in that: The piston is provided with a plurality of through holes, one end of the piston is provided with a damping spring, both ends of the lubrication cavity are provided with sealing pads, and the sealing pads are both sleeved on the push rod.

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