Test system simulating a steel catenary riser touchdown point fault sea bed disturbance

Abstract

The application discloses a test system for simulating seabed disturbance of a steel catenary riser touchdown point fault, which comprises a concrete tank, a riser, a seabed fault simulation device and a riser loading device. The concrete tank is internally formed with a test space. The riser is defined in the test space. The seabed fault simulation device comprises a seabed fault disc, a vertical moving assembly and a horizontal moving assembly. The seabed fault disc comprises a first disc body and a second disc body. The vertical moving assembly enables the first disc body and the second disc body to relatively move along a Z-axis direction, so that a first fault is generated in a seabed soil body. The horizontal moving assembly enables the second disc body and the first disc body to relatively move in an XY plane, so that a second fault is generated in the soil body. The riser loading device adjusts a position of the riser and forms a gully on the soil body. The application can enable the seabed soil body to generate different forms of faults, and further study influences of the seabed fault on gully formation of a riser touchdown point and fatigue life of the riser, so as to ensure accuracy and reliability of the test, and provide a reliable basis for design of the steel catenary riser.

Description

Technical Field

[0001] This invention relates to the field of experimental technology for simulating seabed disturbance caused by faults at the contact point of a steel catenary riser, and particularly to an experimental system for simulating seabed disturbance caused by faults at the contact point of a steel catenary riser. Background Technology

[0002] In the study of seabed disturbance at riser contact points, many issues are related to seabed and riser vibration, such as fatigue life studies at the contact points of steel catenary risers, seabed groove formation, and the influence of riser vibration on the shape of grooves at the contact points. Studying the aforementioned phenomena requires various forms of simulated seabed to conduct scaled-down tests in order to derive solutions through macroscopic measurements and theoretical derivations.

[0003] For the seabed test tanks required for the experiments, the fault patterns of the seabed significantly affect the fatigue life of the riser and the trench formation process. Currently, there are few test methods and systems capable of simulating seabed faults at the riser contact point, and most seabeds use fixed earthen trenches. Furthermore, the fluid inside the riser is usually non-uniform, including multiple liquids such as water, air, and crude oil. This multiphase flow transmission can cause pipe vibration, affecting trench formation at the riser contact point. Currently, there are few test systems that consider the effects of multiphase flow in riser contact point simulation tests.

[0004] Therefore, it is necessary to develop a test system that can generate different types of faults in the seabed soil, and then study the impact of seabed faults on the formation of trenches at riser contact points and riser fatigue life, so as to ensure the accuracy and reliability of the test and provide a reliable basis for the design of steel catenary risers. Summary of the Invention

[0005] To address at least one of the aforementioned problems, this invention provides a test system for simulating seabed disturbance caused by faults at the contact point of a steel catenary riser. The system aims to simulate seabed disturbance caused by faults at the contact point of a steel catenary riser. It can simulate multi-angle faults in the seabed at the riser contact point, including vertical faults (first faults), oblique faults, and horizontal faults (second faults). Furthermore, it can simulate the impact of vibrations caused by multiphase flow within the riser on seabed trenches and riser fatigue life.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A test system for simulating seabed disturbance caused by a fault at the contact point of a steel catenary riser includes: a concrete trough containing a test space; a riser confined within the test space; a seabed fault simulation device located below the riser and adapted to accommodate soil, comprising a seabed fault disk, a vertical movement component, and a lateral movement component. The seabed fault disk comprises a first disk and a second disk separated from each other. The vertical movement component is adapted to cause relative movement between the first and second disks along the Z-axis in a Cartesian coordinate system, thereby forming a first fault in the soil. The lateral movement component is adapted to cause relative movement between the first and second disks in the XY plane spanned by the X and Y axes in the Cartesian coordinate system, thereby forming a second fault in the soil. A riser loading device is adapted to move the riser along the X-axis, Y-axis, and Z-axis directions to adjust the riser position and form trenches in the soil. A multiphase flow simulation device is also included, adapted to input a gas and liquid of a preset type into the riser.

[0008] In the experimental system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, a gap is formed between the first disk and the second disk, and the gap forms an inclination angle with the Y-axis; the seabed fault disk is adapted to rotate in the XY plane to change the value of the inclination angle.

[0009] In the experimental system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the tilt angle is selected from the range (0°, 90°); the lateral movement component is adapted to drive the second disk and the first disk to move relative to each other along an oblique direction, the oblique direction forming an angle with the Y-axis equal to the tilt angle.

[0010] In the experimental system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the seabed fault simulation device further includes lateral baffles. The lateral baffles extending upward are connected to both sides of the lateral moving component, the oblique moving component, the first disk and the second disk along the Y-axis direction to form a soil trough suitable for accommodating soil.

[0011] In the experimental system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the outer periphery of the seabed fault disk is arc-shaped, and the first disk and the second disk are centrally symmetrically arranged; the vertical movement component includes a vertical movement base plate and a first hydraulic cylinder, one end of the vertical movement base plate is configured as a semi-circular end face to fixally connect the side edge of the first disk away from the gap, and its lower side is connected to the bottom wall of the concrete trough through a plurality of spaced first hydraulic cylinders, the first hydraulic cylinder being adapted to drive the vertical movement base plate to move along the Z-axis direction.

[0012] In the test system for simulating seabed disturbance at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the lateral movement component includes an inclined motion base plate, an inclined baffle, a second hydraulic cylinder, and a third hydraulic cylinder. One end of the inclined motion base plate is configured with a semi-circular end face to be fixedly connected to the side edge of the second disc away from the gap. The inclined baffle is provided on both sides along the Y-axis direction. The second hydraulic cylinder is adapted to adjust the inclined baffle so that the inclined baffle is perpendicular to the inclined direction. The third hydraulic cylinder is fixedly disposed relative to the concrete trough and has a hemispherical end for slidably pushing against the outer side surface of the inclined baffle.

[0013] In the test system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the vertical motion base plate and the inclined motion base plate are provided with mounting grooves on both sides along the Y-axis direction; the lateral baffle includes multiple independent baffles, the lower ends of the multiple independent baffles are adapted to be installed in the mounting grooves and are connected in sequence by hinges, the upper ends of the multiple independent baffles are fixed by fixing rods, and the lateral baffles cover the end position of the gap after installation.

[0014] In the test system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the first and second discs are provided with downwardly extending vertical baffles on the lower edge near the gap, so as to prevent the soil from falling from the gap created by the height difference between the first and second discs when a vertical fault is formed.

[0015] In the experimental system for simulating seabed disturbance at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the riser loading device includes a fourth hydraulic cylinder, a slide rail, a fixed support, a fifth hydraulic cylinder, a base, a sixth hydraulic cylinder, a connecting rod, and a crossbeam; the slide rail is configured as two and is respectively located on the upper ends of the two side walls of the concrete trough along the Y-axis direction; the fourth hydraulic cylinder is located on the upper end of the concrete trough wall near the slide rail; the lower side of the fixed support is provided with a plurality of first directional slip rings for slidably connecting to the slide rail, and the upper side is provided with the fifth hydraulic cylinder and at least two sliding rods along the X-axis direction at intervals; The base has multiple second directional slip rings on its lower side for slidably connecting to the slide rod. The upper side has upwardly extending sixth hydraulic cylinders spaced apart, with a first through hole in the middle for mounting the connecting rod. A crossbeam is mounted on the upper end of the sixth hydraulic cylinder. The connecting rod has a water passage and its upper end is fixedly connected to the crossbeam, while its lower end is adapted to be fixedly connected to the end of the riser away from the interface. A fourth hydraulic cylinder moves the fixed support along the Y-axis, a fifth hydraulic cylinder moves the base along the X-axis, and a sixth hydraulic cylinder moves the crossbeam along the Z-axis.

[0016] In the experimental system for simulating seabed disturbance of a fault at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, a first flange is welded to the lower end of the connecting rod, and a second flange connected to the first flange and a third flange connected to the output end of the multiphase flow simulation device are respectively welded to both ends of the riser.

[0017] In the experimental system for simulating seabed disturbance at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the base is provided with a second through hole that connects to the side wall of the first through hole. A watertight valve is provided in the first through hole. The outer peripheral wall of the watertight valve is provided with a first water outlet that communicates with the second through hole, and the inner peripheral wall is provided with a watertight interface. The connecting rod is provided with a second water outlet. When the connecting rod moves along the Z-axis, the movement range of the second water outlet is limited to the range of the watertight interface so that water can be drained into the watertight valve. The second through hole drains liquid to a waste liquid collection device through an external pipe.

[0018] In the experimental system for simulating seabed disturbance at the contact point of a steel catenary riser provided in at least one embodiment of the present invention, the multiphase flow simulation device includes a dual-port pipe, a first three-way valve, a second three-way valve, a first servo motor, a second servo motor, a high-pressure air pump, and a high-pressure fluid chamber; the end of the concrete trough is provided with an interface for the dual-port pipe to pass through, and the output end of the dual-port pipe is provided with a fourth flange for connecting the riser; the first of the two input ends is connected to the high-pressure air pump through the first three-way valve, and the second is connected to the high-pressure fluid chamber through the second three-way valve; the first servo motor and the second servo motor are respectively adapted to control the flow rate of the first three-way valve and the second three-way valve.

[0019] Because the present invention adopts the above technical solution, it has at least the following advantages:

[0020] Soil is placed on the upper side of the seabed fault disc, and a concrete trough can be filled with water and left to stand until the soil solidifies. One end of the riser is connected to a multiphase flow simulation device, and the other end is connected to a riser loading device. The seabed fault disc includes a first disc and a second disc, which are separated from each other. A vertical movement component is adapted to cause relative movement between the first and second discs along the Z-axis in a Cartesian coordinate system, thereby creating a first fault in the Z-axis direction on the soil of the first and second discs. This first fault is a vertical fault. A lateral movement component is adapted to cause relative movement between the first and second discs in the XY plane spanned by the X and Y axes in the Cartesian coordinate system, thereby forming a second fault on the soil of the first and second discs. This second fault includes a horizontal fault formed by relative movement along the X and Y axes, and an oblique fault formed by oblique relative movement between the X and Y axes. In other words, this invention can simulate multi-angle faults on the seabed at the riser's contact point.

[0021] Furthermore, the riser loading device is adapted to move the riser in the X-axis, Y-axis and Z-axis directions, thereby controlling the position and attitude of the riser, allowing the riser to approach, contact and move away from the soil on the seabed fault simulation device. Through repeated collisions of the riser with the soil, grooves are generated on it. In addition, different types of mixed fluids, including gas-liquid mixtures of different proportions, can be input into the riser by a multiphase flow simulation device, thereby simulating the impact of vibrations caused by multiphase flow in the riser on the seabed grooves and the fatigue life of the riser. Attached Figure Description

[0022] Figure 1 A schematic diagram of the structure of a test system for simulating seabed disturbance at the contact point of a steel catenary riser, provided in at least one embodiment of the present invention;

[0023] Figure 2A schematic diagram of the structure from another perspective of the test system for simulating seabed disturbance at the contact point of a steel catenary riser, provided in at least one embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of a seabed formed by soil in at least one embodiment of the present invention;

[0025] Figure 4 A schematic diagram of the structure of the seabed fault simulation device with zinc alloy strip anchors provided in at least one embodiment of the present invention;

[0026] Figure 5 An exploded view of an experimental system for simulating seabed disturbance at the contact point of a steel catenary riser, provided in at least one embodiment of the present invention;

[0027] Figure 6 A schematic diagram of the base and adjacent structural parts of the test system for simulating seabed disturbance at the contact point of a steel catenary riser, provided in at least one embodiment of the present invention.

[0028] Figure 7 This is a schematic diagram of the structure of a multiphase flow simulation device for an experimental system that simulates seabed disturbance at the contact point of a steel catenary riser, as provided in at least one embodiment of the present invention.

[0029] Marked in the attached diagram:

[0030] 1 is a seabed fault simulation device;

[0031] 2 is the riser loading device;

[0032] 3 is a multiphase flow simulation device;

[0033] 4 is the riser;

[0034] 5 represents a concrete trough;

[0035] 6 represents soil;

[0036] 7 represents a trench;

[0037] 8 represents the vertically moving base plate;

[0038] 9 is the first hydraulic cylinder;

[0039] 10 is a side baffle;

[0040] 11 is an independent baffle;

[0041] 12 represents the hinge;

[0042] 13 is the mounting groove on the vertically movable base plate;

[0043] 14 is a fixed rod;

[0044] 15 represents a seabed fault disk;

[0045] 16 is a vertical baffle;

[0046] 17 is an inclined motion base plate;

[0047] 18 is the mounting groove on the inclined moving base plate;

[0048] 19 is an inclined baffle;

[0049] 20 is the second hydraulic cylinder;

[0050] 21 is the third hydraulic cylinder;

[0051] 22 is the first flange;

[0052] 23 is the connecting rod;

[0053] 24 is a watertight valve;

[0054] 25 is the second water outlet;

[0055] 26 is a watertight interface;

[0056] 27 is the second through hole;

[0057] 28 is a crossbeam;

[0058] 29 is the base;

[0059] 30 is the second directional slip ring;

[0060] 31 is a sliding rod;

[0061] 32 is the fifth hydraulic cylinder;

[0062] 33 represents the slide rail;

[0063] 34 is the fourth hydraulic cylinder;

[0064] 35 is the fourth flange;

[0065] 36 is the sixth hydraulic cylinder;

[0066] 37 is the first three-way valve;

[0067] 38 is the first servo motor;

[0068] 39 is the first of the two input terminals of the dual-pass transistor;

[0069] 40 is a high-pressure fluid chamber;

[0070] 41 is the second three-way valve;

[0071] 42 is the seventh flange;

[0072] 43 is the second of the two input terminals of the two-way transistor;

[0073] 44 is the sixth flange. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0075] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the system or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0076] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "assembly," "setup," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0077] In the study of seabed disturbance at riser contact points, many issues are related to seabed and riser vibration, such as fatigue life studies at the contact point of steel catenary risers, seabed groove formation, and the influence of riser vibration on the shape of grooves at the contact point. Researching these phenomena requires scaled-down experiments using various forms of simulated seabed to derive solutions through macroscopic measurements and theoretical derivations. For the seabed test tanks required for these experiments, the fault patterns of the seabed significantly affect the riser's fatigue life and groove formation process. Currently, there are few experimental methods and systems capable of simulating seabed faults at riser contact points; most seabed tests use fixed earthen trenches. Furthermore, the fluid within the riser is typically non-uniform, containing multiple liquids such as water, air, and crude oil. This multiphase flow transmission leads to pipe vibration, affecting groove formation at the riser contact point. Currently, there are few experimental systems that consider the effects of multiphase flow in riser contact point simulation experiments.

[0078] In view of this, embodiments of the present invention provide a test system for simulating seabed disturbance caused by faults at the contact point of a steel catenary riser. Specifically, by causing relative movement of the first and second disks along the Z-axis in the Cartesian coordinate system and within the XY plane spanned by the X and Y axes in the Cartesian coordinate system using a seabed fault simulation device, it is possible to simulate multi-angle faults in the seabed at the riser contact point, including vertical faults (first faults), oblique faults, and horizontal faults (second faults). Furthermore, it can also simulate the impact of vibrations caused by multiphase flow within the riser on the seabed trench and the riser's fatigue life.

[0079] Reference Figures 1 to 7 As shown, at least one embodiment of the present invention provides a test system for simulating seabed disturbance caused by a fault at the contact point of a steel catenary riser, comprising: a concrete tank 5, a riser 4, a seabed fault simulation device 1, a riser loading device 2, and a multiphase flow simulation device 3. A test space is formed within the concrete trough 5; the riser 4 is confined within the test space; the seabed fault simulation device 1 is located below the riser 4 and is adapted to place soil 6 on it, which includes a seabed fault disk 15, a vertical movement component, and a lateral movement component. The seabed fault disk 15 includes a first disk and a second disk that are separated from each other. The vertical movement component is adapted to cause the first disk and the second disk to move relative to each other along the Z-axis in the Cartesian coordinate system, thereby forming a first fault in the soil 6. The lateral movement component is adapted to cause the first disk and the second disk to move relative to each other in the XY plane spanned by the X-axis and Y-axis in the Cartesian coordinate system, thereby forming a second fault in the soil 6; the riser loading device 2 is adapted to move the riser 4 in the X-axis, Y-axis, and Z-axis directions, thereby adjusting the position of the riser 4 and forming trenches on the soil 6; the multiphase flow simulation device 3 is adapted to input a preset type of gas and liquid into the riser 4.

[0080] In the above embodiment of the test system for simulating seabed disturbance of the fault at the contact point of the steel catenary riser, soil 6 is set on the upper side of the seabed fault disk 15, etc., and the concrete trough 5 can be filled with water and left to stand until the soil 6 is solidified. One end of the riser 4 is connected to the multiphase flow simulation device 3, and the other end is connected to the riser loading device 2. The seabed fault disk 15 includes a first disk and a second disk that are separated from each other. The vertical moving component is adapted to cause the first disk and the second disk to move relative to each other along the Z-axis in the Cartesian coordinate system, thereby causing the soil 6 on the first disk and the second disk to form a first fault in the Z-axis direction. The first fault is a vertical fault. The lateral moving component is adapted to cause the first disk and the second disk to move relative to each other in the XY plane spanned by the X-axis and the Y-axis in the Cartesian coordinate system, thereby causing the soil 6 on the first disk and the second disk to form a second fault. The second fault includes a horizontal fault formed by relative movement along the X-axis and the Y-axis, and an oblique fault formed by oblique relative movement between the X-axis and the Y-axis. That is, the present invention can simulate the multi-angle faults of the seabed in the section where the riser 4 touches the ground.

[0081] Furthermore, the riser loading device 2 is adapted to move the riser 4 in the X-axis, Y-axis and Z-axis directions, thereby controlling the position and attitude of the riser 4, allowing the riser 4 to approach, contact and move away from the soil 6 on the seabed fault simulation device 1. The riser 4 repeatedly collides with the soil 6 to create trenches on it. In addition, different types of mixed fluids, including gas-liquid mixed fluids of different proportions, can be input into the riser 4 by the multiphase flow simulation device 3, thereby simulating the effect of vibration caused by multiphase flow in the riser 4 on the seabed trench 7 and the fatigue life of the riser 4.

[0082] The following is a detailed description of the experimental system for simulating seabed disturbance at the contact point of a steel catenary riser, provided in an embodiment of the present invention, with reference to the accompanying drawings.

[0083] For example, the concrete trough 5 is configured as a semi-enclosed box structure, and its overall shape is cuboid or close to cuboid.

[0084] For example, in this embodiment of the invention, the overall length direction of the riser 4 is consistent with the length direction of the concrete trough 5, but during the movement of the riser 4, the overall length direction of the riser 4 and the length direction of the concrete trough 5 may be adapted to deviate.

[0085] It should be noted that, for example, regarding the limitation of directions, for ease of description, at least one embodiment of the present invention establishes a Cartesian coordinate system with the width direction of the concrete trough 5 as the X-axis, the length direction as the Y-axis, and the height direction as the Z-axis. However, the specific directions of the present invention are relative to each other's components or actions, and are not restrictive.

[0086] For example, the seabed fault simulation device 1 is set at the middle of the bottom of the test space, and the two ends of the riser 4 are respectively set close to the two ends of the concrete trough 5 along its length. For example, one end of the riser 4 along its length is fixedly connected to the first end of the concrete trough 5 along its length, and the other end of the riser 4, which is opposite to the first end of the concrete trough 5 along its length, extends towards the second end and is driven and connected by the riser loading device 2. The riser loading device 2 drives the riser 4 to move.

[0087] For example, in at least one embodiment of the present invention, a gap is formed between the first and second discs, and the gap forms an inclination angle with the Y-axis; the seabed fault disk 15 is adapted to rotate in the XY plane, thereby changing the value of the inclination angle. In this way, the first and second discs move relative to each other, forming gaps of different sizes and / or different directions and / or different shapes, thereby causing soil 6 to fall from the gaps and form various types of faults. For example, the rotation of the seabed fault disk 15 can change the direction of the gap, i.e., the fault, and can alter the angle formed between the fault and the riser 4.

[0088] For example, refer to Figure 4 As shown, in at least one embodiment of the present invention, the tilt angle is selected from the range (0°, 90°); the lateral movement component is adapted to drive the second disk and the first disk to move relative to each other along an oblique direction, the oblique direction forming an angle with the Y-axis equal to the tilt angle. Thus, the direction of relative movement between the second disk and the first disk is between the X-axis and the Y-axis, and the extension direction of the gap between the first disk and the second disk is also between the X-axis and the Y-axis, thus forming an oblique fault.

[0089] For example, in one embodiment of the present invention, the tilt angle is 10°, 20°, 30°, 40°, 50°, 60°, 70°, or 80°. It should be noted that the orientation of the tilt angle opening is not specifically limited.

[0090] For example, refer to Figure 4 As shown, in at least one embodiment of the present invention, the seabed fault simulation device 1 further includes lateral baffles 10. Lateral baffles 10 extending upwards are connected to both sides of the lateral moving assembly, the oblique moving assembly, the first disc, and the second disc along the Y-axis direction to form a soil trough suitable for accommodating the soil 6. Thus, the lateral baffles 10 form a soil trough for accommodating the soil 6 within the lateral moving assembly, the oblique moving assembly, the first disc, and the second disc, confining the soil 6 within the trough. When the riser 4 is repeatedly vibrated, the soil 6 can be confined to its original position to facilitate the experiment.

[0091] For example, refer to Figure 4As shown, in at least one embodiment of the present invention, the outer periphery of the seabed fault disk 15 is arc-shaped, and the first disk and the second disk are centrally symmetrically arranged; the vertical moving assembly includes a vertical moving base plate 8 and a first hydraulic cylinder 9. One end of the vertical moving base plate 8 is configured as a semi-circular end face to fixally connect to the side edge of the first disk away from the gap, and its lower side is connected to the bottom wall of the concrete trough 5 through a plurality of spaced first hydraulic cylinders 9. The first hydraulic cylinders 9 are adapted to drive the vertical moving base plate 8 to move along the Z-axis direction.

[0092] In this way, the first and second disks can be driven to move relative to each other along the Z-axis.

[0093] For example, the vertical motion base plate 8 is located on the side of the first disc body away from the second disc body.

[0094] For example, the outer periphery of the seabed fault disk 15 is arc-shaped, that is, the outer periphery of the first disk is arc-shaped. This allows it to fit with the semi-circular end face of the vertically moving base plate 8. After the first disk rotates, the contact point between the two remains compatible, ensuring a seal against the soil 6. For example, in one embodiment of the invention, the outer periphery of the first disk is provided with a radially extending groove, and the semi-circular end face of the vertically moving base plate 8 is provided with a protrusion that engages with the groove. In another embodiment of the invention, the first disk and the vertically moving base plate 8 can also be connected via a magnetic component.

[0095] For example, the first and second discs have the same shape, both being semi-circular. Of course, in other embodiments, the shapes of the first and second discs may not be the same; for example, both the first and second discs may be configured as cleft circumferences, and the notch in the first disc may be larger than the notch in the second disc.

[0096] For example, four first hydraulic cylinders 9 may be configured, and the four first hydraulic cylinders 9 are arranged in a rectangular pattern near the corners of the vertical motion base plate 8.

[0097] However, this design is not limited to this. In other embodiments, the first hydraulic cylinder 9 may also be configured as, for example, an electric motor drive.

[0098] For example, refer to Figure 4 As shown, in at least one embodiment of the present invention, the lateral movement assembly includes an inclined motion base plate 17, an inclined baffle 19, a second hydraulic cylinder 20, and a third hydraulic cylinder 21. One end of the inclined motion base plate 17 is configured with a semi-circular end face to be fixedly connected to the side edge of the second disc away from the gap. Inclined baffles 19 are provided on both sides along the Y-axis direction. The second hydraulic cylinder 20 is adapted to adjust the inclined baffles 19 so that the inclined baffles 19 are perpendicular to the inclined direction. The third hydraulic cylinder 21 is fixedly disposed relative to the concrete trough 5 and has a hemispherical end for slidably pushing against the outer surface of the inclined baffles 19.

[0099] In this way, it is possible to drive the first and second discs to move relative to each other along an oblique direction.

[0100] For example, the inclined motion base plate 17 is located on the side of the second plate that is away from the first plate.

[0101] For example, the semi-circular end face of the inclined motion base plate 17 is adapted to the arc-shaped outer periphery of the second disc. After the second disc rotates by a predetermined angle, the contact point between the two remains adapted to ensure the sealing of the soil 6. For example, in one embodiment of the present invention, the outer periphery of the second disc is provided with a radially extending female buckle, and the semi-circular end face of the inclined motion base plate 17 is provided with a male buckle adapted to the female buckle. In another embodiment of the present invention, the second disc and the inclined motion base plate 17 can also be connected by a magnetic component.

[0102] For example, four inclined baffles 19, four second hydraulic cylinders 20, and four third hydraulic cylinders 21 are provided. The four inclined baffles 19 are rectangularly distributed and hinged to the side edge of the inclined moving base plate 17. The second hydraulic cylinder 20 is located on the inner side of the inclined baffles 19 to adjust the inclination angle of the inclined baffles 19. The third hydraulic cylinder 21 is fixedly installed on, for example, the inner wall of the concrete trough 5, corresponding to the outer side of the inclined baffles 19. When the third hydraulic cylinder 21 is in operation, its end pushes against the outer side of the inclined baffles 19, causing the inclined moving base plate 17 to move obliquely.

[0103] However, this design is not limited to this. In other embodiments, the second hydraulic cylinder 20 and the third hydraulic cylinder 21 may also be configured as, for example, motor-driven devices.

[0104] For example, refer to Figure 4 As shown, in at least one embodiment of the present invention, both sides of the vertical moving base plate 8 and the inclined moving base plate 17 along the Y-axis direction are provided with mounting grooves 13 (18); the lateral baffle 10 includes a plurality of independent baffles 11, the lower ends of the plurality of independent baffles 11 are adapted to be installed in the mounting grooves 13 (18) and are connected in sequence by hinges 12, the upper ends of the plurality of independent baffles 11 are fixed by fixing rods 14, and the lateral baffle 10 is installed to cover the end position of the gap so as to maintain the soil 6 on the first and second discs. In this way, the lateral baffle 10 can be bent and extended to adapt to the setting position and extension direction of the vertical moving base plate 8 and the inclined moving base plate 17, etc., and it has different lengths by disassembling and assembling different numbers of independent baffles 11.

[0105] For example, refer to Figure 4As shown, in at least one embodiment of the present invention, the first and second discs are provided with downwardly extending vertical baffles 16 near the lower edge of the gap to prevent soil 6 from falling through the gap created by the height difference between the first and second discs when a vertical fault is formed. For example, the downwardly extending dimension of the vertical baffles 16 is greater than or equal to the height difference between the first and second discs when a vertical fault is formed.

[0106] For example, refer to Figure 5 As shown, in at least one embodiment of the present invention, the riser loading device 2 includes a fourth hydraulic cylinder 34, a slide rail 33, a fixed support, a fifth hydraulic cylinder 32, a base 29, a sixth hydraulic cylinder 36, a connecting rod 23, and a crossbeam 28.

[0107] For example, two slide rails 33 are configured and are respectively located on the upper ends of the two side walls of the concrete trough 5 along the Y-axis direction, and the fourth hydraulic cylinder 34 is located on the upper end of the concrete trough 5 wall near the slide rails 33.

[0108] For example, the lower side of the fixed support is provided with multiple first directional slip rings for slidably connecting to the slide rail 33, and the upper side is provided with a fifth hydraulic cylinder 32 and at least two slide rods 31 along the X-axis direction. Optionally, the first directional slip rings can be configured as four in a rectangular distribution. Further, the slide rods 31 can be configured as, for example, two.

[0109] For example, the lower side of the base 29 is provided with a plurality of second directional slip rings 30 for slidably connecting to the slide rod 31, and the upper side is provided with upwardly extending sixth hydraulic cylinders 36 spaced apart. A first through hole is opened in the middle for mounting a connecting rod 23, and a crossbeam 28 is provided at the upper end of the sixth hydraulic cylinder 36. Optionally, the second directional slip rings 30 can be configured as four in a rectangular arrangement. Further, the sixth hydraulic cylinder 36 can be configured as, for example, two. However, this design is not limited to this; in other embodiments, the sixth hydraulic cylinder 36 can also be configured as, for example, a motor drive assembly.

[0110] For example, the connecting rod 23 has a water passage and is fixedly connected to the crossbeam 28 at the upper end, and is suitable for fixedly connecting to the end of the riser 4 away from the interface at the lower end.

[0111] For example, the fourth hydraulic cylinder 34 is used to move the fixed support along the Y-axis, the fifth hydraulic cylinder 32 is used to move the base 29 along the X-axis, and the sixth hydraulic cylinder 36 is used to move the crossbeam 28 along the Z-axis. In this way, the riser loading device 2 can drive the riser 4 to move in the X-axis, Y-axis, and Z-axis directions.

[0112] For example, refer to Figure 5As shown, in at least one embodiment of the present invention, a first flange 22 is welded to the lower end of the connecting rod 23, and a second flange connected to the first flange 22 and a third flange connected to the output end of the multiphase flow simulation device 3 are respectively welded to both ends of the riser 4. In this way, the riser 4 can be detachably connected to the connecting rod 23 and the multiphase flow simulation device 3.

[0113] For example, refer to Figure 6 As shown, in at least one embodiment of the present invention, the base 29 has a second through hole 27 communicating from the first through hole to its side wall. A watertight valve 24 is provided in the first through hole. The outer peripheral wall of the watertight valve 24 has a first water outlet communicating with the second through hole 27, and the inner peripheral wall has a watertight interface 26. The connecting rod 23 has a second water outlet. When the connecting rod 23 moves along the Z-axis, the movement range of the second water outlet is limited to the range of the watertight interface 26, so that water can be drained into the watertight valve 24. The second through hole 27 drains liquid to a waste liquid collection device through an external pipe. In this way, the fluid in the riser 4 enters the second through hole 27 through the watertight interface 26 and the watertight valve 24, and then drains liquid through the external pipe to, for example, a waste liquid collection tank for collection.

[0114] For example, refer to Figure 7 As shown, in at least one embodiment of the present invention, the multiphase flow simulation device 3 includes a dual-port pipe, a first three-way valve 37, a second three-way valve 41, a first servo motor 38, a second servo motor, a high-pressure air pump, and a high-pressure fluid chamber 40. The concrete tank 5 has an interface at its end for the dual-port pipe to pass through, and the output end of the dual-port pipe is provided with a fourth flange 35 for connecting to the third flange of the riser pipe 4. The first input end 39 is connected to the high-pressure air pump through the first three-way valve 37, and the second input end 43 is connected to the high-pressure fluid chamber 40 through the second three-way valve 41. The first servo motor 38 and the second servo motor are respectively adapted to control the flow rates of the first three-way valve 37 and the second three-way valve 41.

[0115] Furthermore, referring to Figure 7 As shown, the fluid inlet of the first three-way valve 37 is provided with a fifth flange, the output of the high-pressure air pump is provided with a sixth flange 44 for connecting to the fifth flange, the fluid inlet of the second three-way valve 41 is provided with a seventh flange 42, and the output of the high-pressure fluid chamber 40 is provided with an eighth flange for connecting to the seventh flange 42.

[0116] For example, refer to Figures 1 to 7 As shown, the following provides an operation method for the test system for simulating seabed disturbance at the contact point of a steel catenary riser according to at least one embodiment of the present invention:

[0117] The angle between the seabed (soil 6) fault and the trench 7 is defined as the inclination angle θ; the distance between the seabed trench 7 and the fault is defined as the horizontal displacement distance l; the vertical height difference of the seabed plane is defined as the seabed uplift height h. The inclination angle θ of the seabed fault disc 15 is adjusted to ensure that the initial state of the seabed is on the same horizontal plane. The lateral baffle 10 is laid out, with its end fixed to the seabed fault disc 15 near the fault, its lower end fixed to the groove, and its upper end fixed with the fixing rod 14. The inclination angle of the inclined baffles 19 on both sides of the inclined motion base plate 17 is adjusted so that the third hydraulic cylinder 21 can push the inclined baffles 19 to make the seabed move in an inclined direction. After installing the riser loading device 2 and the riser 4, the multiphase flow simulation device 3 is connected and turned on to make the riser 4 vibrate, simulating the state of the riser 4 under real working conditions.

[0118] The riser loading device 2 is activated, causing the riser 4 to move repeatedly, forming a groove 7 on the seabed. When the groove 7 no longer shows significant changes, the riser 4 is lifted away from the seabed, and the hydraulic cylinders on the seabed are activated to create a fault in the seabed soil 6, for example, raising the height of one side of the seabed by h, and moving the fault along the X-axis by l. Because of the fault in the soil 6, when the riser 4 contacts the seabed again, a new groove 7 will form. During this process, the fatigue life of the riser 4 will be significantly reduced, thus studying the influence of seabed faults on the fatigue life of the riser 4.

[0119] It should be noted that the "and / or" in the text includes three options. Taking "A and / or B" as an example, it includes technical option A, technical option B, and technical option that satisfies both A and B.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A test system for simulating seabed disturbance caused by a fault at the contact point of a steel catenary riser, characterized in that, include: A concrete trough, with an experimental space inside; The riser is confined within the test space; The seabed fault simulation device is located below the riser and is adapted to be placed on the soil. It includes a seabed fault disk, a vertical moving component and a horizontal moving component. The seabed fault disk includes a first disk body and a second disk body that are separated from each other. The vertical moving component is adapted to cause the first disk body and the second disk body to move relative to each other along the Z-axis in the Cartesian coordinate system, thereby causing the soil body to form a first fault. The lateral movement component is adapted to cause relative movement between the first and second disks in the XY plane spanned by the X and Y axes in the Cartesian coordinate system, thereby forming a second fault in the soil. A gap is formed between the first disk and the second disk, and the gap forms an inclination angle with the Y-axis; the seabed fault disk is adapted to rotate in the XY plane to change the value of the inclination angle; The lateral movement assembly includes an inclined motion base plate, an inclined baffle, a second hydraulic cylinder, and a third hydraulic cylinder. One end of the inclined motion base plate is configured with a semi-circular end face to be fixedly connected to the side edge of the second disc away from the gap. The inclined baffle is provided on both sides along the Y-axis direction. The second hydraulic cylinder is adapted to adjust the inclined baffle so that the inclined baffle is perpendicular to the inclined direction. The third hydraulic cylinder is fixedly disposed relative to the concrete trough and has a hemispherical end for slidably pushing against the outer side of the inclined baffle. A riser loading device is adapted to move the riser in the X-axis direction, the Y-axis direction and the Z-axis direction, thereby adjusting the position of the riser and forming trenches in the soil. as well as A multiphase flow simulation device, suitable for inputting a preset type of gas and liquid into the riser.

2. The experimental system for simulating seabed disturbance at the contact point of a steel catenary riser according to claim 1, characterized in that, The tilt angle is selected from the range (0°, 90°); The lateral movement component is adapted to drive the second disk and the first disk to move relative to each other along an oblique direction, the oblique direction forming an angle with the Y-axis equal to the tilt angle.

3. The experimental system for simulating seabed disturbance at the contact point of a steel catenary riser according to claim 2, characterized in that, The seabed fault simulation device also includes lateral baffles. The lateral moving component, the oblique moving component, the first disk and the second disk are all connected to the upward-extending lateral baffles on both sides along the Y-axis to form a soil trough suitable for accommodating soil.

4. The test system for simulating seabed disturbance at the contact point of a steel catenary riser according to claim 3, characterized in that, The outer periphery of the seabed fault disk is arc-shaped, and the first disk and the second disk are arranged in a centrally symmetrical manner; The vertical moving assembly includes a vertical moving base plate and a first hydraulic cylinder. One end of the vertical moving base plate is configured with a semi-circular end face to be fixedly connected to the side edge of the first disc away from the gap. Its lower side is connected to the bottom wall of the concrete trough through a plurality of spaced first hydraulic cylinders. The first hydraulic cylinder is adapted to drive the vertical moving base plate to move along the Z-axis direction.

5. The test system for simulating seabed disturbance at the contact point of a steel catenary riser according to claim 4, characterized in that, The vertical motion base plate and the inclined motion base plate are each provided with mounting grooves along both sides of the Y-axis. The lateral baffle includes multiple independent baffles, the lower ends of which are adapted to be installed in the mounting grooves and are connected sequentially by hinges. The upper ends of which are fixed by fixing rods, and the lateral baffles, after installation, cover the end of the gap; and / or The first and second discs are provided with downwardly extending vertical baffles on their lower edges near the gap, to prevent the soil from falling through the gap created by the height difference between the first and second discs when a vertical fault is formed.

6. The test system for simulating seabed disturbance at the contact point of a steel catenary riser according to any one of claims 1 to 5, characterized in that, The riser loading device includes a fourth hydraulic cylinder, a slide rail, a fixed support, a fifth hydraulic cylinder, a base, a sixth hydraulic cylinder, a connecting rod, and a crossbeam. The slide rails are configured as two and are respectively located on the upper ends of the two side walls of the concrete trough along the Y-axis direction. The fourth hydraulic cylinder is located on the upper end of the concrete trough wall near the slide rails. The lower side of the fixed support is provided with a plurality of first directional slip rings for slidably connecting to the slide rail, and the upper side is provided with the fifth hydraulic cylinder and at least two slide rods along the X-axis direction at intervals. The base has multiple second directional slip rings on its lower side for slidably connecting to the slide rod, and the upper side has upwardly extending sixth hydraulic cylinders spaced apart. A first through hole is provided in the middle for the connecting rod, and the crossbeam is provided at the upper end of the sixth hydraulic cylinder. The connecting rod is provided with a water passage and its upper end is fixedly connected to the crossbeam, while its lower end is adapted to be fixedly connected to the end of the riser that is away from the interface. The fourth hydraulic cylinder is used to move the fixed support along the Y-axis direction, the fifth hydraulic cylinder is used to move the base along the X-axis direction, and the sixth hydraulic cylinder is used to move the crossbeam along the Z-axis direction.

7. The test system for simulating seabed disturbance at the contact point of a steel catenary riser according to claim 6, characterized in that, The lower end of the connecting rod is welded with a first flange, and both ends of the riser are respectively welded with a second flange connected to the first flange and a third flange connected to the output end of the multiphase flow simulation device; and / or The base has a second through hole that connects to the first through hole and its side wall. A watertight valve is installed in the first through hole. The outer peripheral wall of the watertight valve has a first water outlet that communicates with the second through hole, and the inner peripheral wall has a watertight interface. The connecting rod has a second water outlet. When the connecting rod moves along the Z-axis, the movement range of the second water outlet is limited to the range of the watertight interface so that water can be drained into the watertight valve. The second through hole drains liquid to the waste liquid collection device through an external pipe.

8. The test system for simulating seabed disturbance at the contact point of a steel catenary riser according to any one of claims 1 to 5, characterized in that, The multiphase flow simulation device includes a dual-pass pipe, a first three-way valve, a second three-way valve, a first servo motor, a second servo motor, a high-pressure air pump, and a high-pressure fluid chamber. The concrete trough end is provided with an interface for the double-pass pipe to pass through, and the output end of the double-pass pipe is provided with a fourth flange for connecting the riser. The first of the two input ends is connected to the high-pressure air pump through the first three-way valve, and the second is connected to the high-pressure fluid chamber through the second three-way valve. The first servo motor and the second servo motor are respectively adapted to control the flow of the first three-way valve and the second three-way valve.

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