Dual-mode interconnection driving simulation device of liquid-gas combined tensioner

Abstract

The application provides a double-mode interconnected driving simulation device of a liquid-gas combined tensioner, relates to the field of ocean engineering equipment testing, and comprises a translation mechanism, a rotation adjusting mechanism, a vertical movement and inclination simulation mechanism, a riser, a support and a combined tensioner mechanism. The application adopts a positive configuration of active control simulation at the bottom and passive response verification at the top. The device is sequentially composed of a bottom drilling platform translation mechanism, a rotation adjusting mechanism, a middle drilling platform vertical movement and inclination simulation mechanism, a top ring direct-acting liquid-gas combined tensioner at the top of a riser assembly and the like from bottom to top, so that the translation mechanism can simulate the horizontal drift movement of the ocean platform, the rotation adjusting mechanism can reproduce the yaw movement posture of the platform, the vertical movement and inclination simulation mechanism can simulate the inclination posture of the offshore platform under different sea conditions, and the combined tensioner mechanism can simulate the mechanical characteristics of the real wellhead connection of the tensioner.

Description

Technical Field

[0001] This invention relates to the field of marine engineering equipment testing, specifically to a dual-mode interconnected drive simulation device for a liquid-gas composite tensioner. Background Technology

[0002] The current status of deepwater oil and gas development and the application of dry production trees: As offshore oil and gas exploration and development moves towards ultra-deep waters (depths exceeding 1500m), reducing equipment investment and operating costs has become a core challenge in engineering design. Against this backdrop, dry production tree floating production systems with top-tensioned risers are gradually becoming the preferred solution for deepwater development due to their wellhead equipment being located on the platform deck, facilitating maintenance and reducing operating costs. Among these, tension leg platforms, as a typical dry production tree floating production facility, are anchored to the seabed through a high-strength cable structure, utilizing buoyancy to maintain the platform's stability on the sea surface.

[0003] Due to limitations in the stiffness of the chain-link structure and material costs, tension leg platforms are typically suitable for development in water depths up to 1500m; for deeper waters, deep-draft column platforms are more commonly used. Because floating platforms experience six degrees of freedom of motion (heave, pitch, roll, etc.) under the influence of waves, tides, and currents, while the seabed wellhead remains relatively fixed, a tension compensation device, i.e., a tensioner, must be installed between the platform and the top of the riser to prevent the rigidly connected riser from breaking or buckling under pressure due to platform movement.

[0004] In existing technologies, tension leg platforms mainly employ hydraulic-pneumatic tensioners. Among them, the Ram-type riser tensioner is widely used in deep-water operations under harsh sea conditions due to its compact structure and high load-bearing capacity. This type of tensioner utilizes the compressibility of high-pressure gases such as nitrogen to store energy, and compensates for platform displacement through the extension and retraction of hydraulic cylinders, maintaining a constant tension at the top of the riser.

[0005] Due to the limitations and shortcomings of existing dynamic experimental techniques, the dynamic performance of Ram-type tensioners must be verified in a terrestrial environment before they can be put into practical engineering applications. However, for such special equipment with large tonnage, long stroke, and high pressure, existing experimental simulation techniques have significant technical bottlenecks and safety hazards, specifically in the following two aspects: First, the experimental setup presents structural safety risks: existing tensioner test benches mostly use a "gantry suspension" structure, which involves building a giant frame tens of meters high to suspend the riser and tensioner in the air. This top-heavy, high-center-of-gravity structure is prone to significant swaying or even resonance when simulating dynamic loads and high-frequency wave conditions, posing a great risk of collapse. Furthermore, the installation and maintenance of the equipment are extremely difficult.

[0006] Second, there is a lack of capability to simulate complex sea conditions. In real sea conditions, the motion of a tension leg platform is multi-dimensional; the platform's heave is often accompanied by pitching, rolling, and horizontal drift. This means that the tensioner's piston rod must withstand not only axial tension but also enormous lateral loads. Lateral forces cause severe nonlinear friction between the piston rod and the seal, accelerating seal failure. Most existing experimental setups can only provide a single vertical reciprocating motion, failing to physically reproduce this complex "axial motion + lateral eccentricity" condition, resulting in severely distorted assessments of seal life and lateral force resistance. Summary of the Invention

[0007] To address the shortcomings of the existing technology, the present invention aims to provide a dual-mode interconnected drive simulation device for a liquid-gas composite tensioner. This device ensures the structural stability of the tensioner test bench and can perform multi-dimensional movements such as pitching, rolling, and horizontal drift to simulate complex sea conditions. The specific technical solution is as follows: A dual-mode interconnected drive simulation device for a liquid-gas composite tensioner, comprising: Translation mechanism; Rotary adjustment mechanism: It is mounted on the translation mechanism and can be driven by the translation mechanism to move horizontally in the orthogonal direction; Vertical movement and tilting simulation mechanism: includes a fixed platform mounted on a rotary adjustment mechanism, which can be driven by the rotary adjustment mechanism to rotate along a vertical axis; several active hydraulic cylinders are vertically mounted on the fixed platform in a circular array, with the movable end of each active hydraulic cylinder facing upwards, and the piston rod of each active hydraulic cylinder is connected to a third Hooke hinge, and several third Hooke hinges converge to connect to the riser fixing ring; each active hydraulic cylinder is connected to a corresponding second accumulator, the number of active hydraulic cylinders is even, and the several active hydraulic cylinders are divided into several linkage units, each linkage unit includes any two adjacent active hydraulic cylinders in the circular array, and the rodless chambers of the two active hydraulic cylinders in each linkage unit are connected to the second accumulator through an oil supply pipe, forming an interconnected hydraulic pipeline structure; Riser: Installed vertically inside the riser fixing ring; The support frame has several top rings arranged in a circular array on its top. Composite tensioner mechanism: includes a tensioner base connected to the riser and several passive hydraulic cylinders. Several second Hooke hinges are installed in a circular array on the tensioner base. A first Hooke hinge is installed on each top ring. The number and position of the second Hooke hinges correspond one-to-one with the first Hooke hinges and are used to install several passive hydraulic cylinders. The rear cover end of the passive hydraulic cylinder is connected to the first Hooke hinge, and the piston rod is connected to the second Hooke hinge.

[0008] Furthermore: the translation mechanism includes a first moving unit and a second moving unit. The first moving unit is provided with a plurality of first slide rails that are parallel to each other, and the second moving unit is slidably mounted on the plurality of first slide rails on the first moving unit. The second moving unit is provided with several parallel second slide rails, and a rotary working adjustment mechanism pad is slidably mounted on the several second slide rails for mounting the rotary adjustment mechanism.

[0009] Furthermore: the first slide rail includes a base plate disposed on the first moving unit and a slide base disposed on the base plate. The top of the base plate is also provided with a slide top plate, thereby forming a slide groove between the base plate, the slide base and the slide top plate. The movable slide is slidably installed in the slide groove. The movable slide is connected to the second moving unit to drive the second moving unit to translate. The structure of the second slide rail is the same as that of the first slide rail.

[0010] Furthermore, slide baffles are installed at both ends of the base plate along its length to prevent the movable slide from detaching from the slide groove.

[0011] Furthermore, each oil pipeline is connected to a solenoid valve, and each solenoid valve is connected to a control unit to control the opening and closing of the solenoid valve, so as to realize the switching between linkage mode and independent mode.

[0012] Furthermore: each second accumulator is connected to its corresponding active hydraulic cylinder via an oil supply pipe, and is also connected to one of the active hydraulic cylinders adjacent to the corresponding active hydraulic cylinder.

[0013] Furthermore, each passive hydraulic cylinder is equipped with a first accumulator and a first nitrogen cylinder. Each first nitrogen cylinder is connected to its corresponding first accumulator, and each first accumulator is connected to its corresponding passive hydraulic cylinder to provide hydraulic energy to each passive hydraulic cylinder.

[0014] Furthermore, each active hydraulic cylinder is equipped with a second nitrogen cylinder, and several second accumulators are connected to the second nitrogen cylinders to provide hydraulic energy to each active hydraulic cylinder.

[0015] Furthermore, each active hydraulic cylinder and the second accumulator connected thereto are also connected by a backflow valve oil supply pipe, which is equipped with a backflow valve to limit the oil supply speed and prevent backflow impact in the event of system failure.

[0016] Furthermore, each passive hydraulic cylinder is inclined from top to bottom and positioned towards the inner side of the circumferential array.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a dual-mode interconnected drive simulation device for a hydraulic-gas composite tensioner, employing an upright configuration of "bottom active control simulation + top passive response verification". The device, from bottom to top, consists of a bottom drilling platform translation mechanism, a rotation adjustment mechanism, a middle drilling platform vertical movement and tilting simulation mechanism, and a top-ring direct-acting hydraulic-gas composite tensioner at the top of the riser assembly. Thus, the translation mechanism can simulate the horizontal drift motion of an offshore platform, the rotation adjustment mechanism can reproduce the platform's yaw motion attitude, the vertical movement and tilting simulation mechanism can simulate the tilting attitude of an offshore platform under different sea conditions, and the composite tensioner mechanism can simulate the mechanical characteristics of a real wellhead connection for the tensioner.

[0018] 2. This invention employs a unique hydraulic pipeline design. To address the issues of slow hydraulic response and single-point failure under high-flow conditions, it combines independent and joint control of the active hydraulic cylinders, adopting a parallel structure of "one cylinder connected to two accumulators, one accumulator supplying two cylinders." This allows each hydraulic cylinder to have double the oil inlet and outlet paths simultaneously during high-frequency, high-amplitude extension and retraction movements, greatly improving the hydraulic oil throughput efficiency and eliminating action lag. If one of the second accumulators fails, other second accumulators in the network can still provide pressure to that hydraulic cylinder, preventing experimental interruption.

[0019] 3. In this invention, solenoid valves are installed on each oil supply pipe between the active hydraulic cylinder and the second accumulator, and controlled by a control unit. The on / off state between each hydraulic cylinder chamber and the interconnection network can be flexibly adjusted according to the experimental task. When the valves are fully open, the pressure of each power unit is complementary, providing extremely high operational stability and fault tolerance for long-cycle experiments. When the system is switched to an independent control mode of 'one accumulator corresponding to one hydraulic cylinder' by closing specific valves, the system can adjust the pressure of the high-pressure hydraulic chamber of each hydraulic cylinder to extend the piston rod of the actuator cylinder by different lengths, thereby accurately simulating the different tilting conditions of the platform under different sea conditions. This allows for obtaining the working data of the tested top ring direct-push hydraulic-gas composite tensioner under different sea conditions, facilitating subsequent related research. This special connection structure not only enhances the simulation realism of the entire device to the variable deep-sea environment but also significantly expands the testing range and control accuracy of the entire simulation experimental device. Furthermore, a backflow valve oil supply pipe is integrated into the hydraulic pipeline to ensure system safety.

[0020] 4. In the composite tensioner mechanism at the top of this invention, when the central motion simulation system generates an upward swaying displacement, the cylinder of the top tensioner moves upward synchronously. At this time, the hydraulic oil in the high-pressure hydraulic chamber (i.e., the pressure chamber) of the passive hydraulic cylinder is squeezed and discharged into the first accumulator through the pipeline, inducing the piston rod to generate an upward retraction motion relative to the cylinder. Conversely, when the bottom motion simulation system is in the descending phase, the passive hydraulic cylinder moves downward as a whole. Under the pressure of the first accumulator, the hydraulic oil is injected in reverse into the working chamber of the passive hydraulic cylinder, driving the piston rod to generate a downward extension motion relative to the cylinder. Through this relative motion logic of cylinder follow-up and piston compensation, the top ring direct-acting hydraulic-pneumatic composite tensioner component under test can accurately provide constant tension and displacement compensation for the riser under platform fluctuations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of the simulation device disclosed in this invention; Figure 2 This is a three-dimensional structural diagram of the deep-sea state simulation system disclosed in this invention; Figure 3 This is a partially enlarged schematic diagram of the deep-sea state simulation system disclosed in this invention; Figure 4 This is a schematic diagram of the vertical movement and tilting simulation mechanism of the central drilling platform of the present invention. Figure 5 This is a schematic diagram of the bottom drilling platform translation mechanism disclosed in this invention; Figure 6 This is a schematic diagram of the overall structure of the first slide rail disclosed in this invention; Figure 7 This is a schematic diagram of the movable slide structure disclosed in this invention; Figure 8 This is a schematic diagram of the rotary table component disclosed in this invention; Figure 9 This is a schematic diagram of the structure of the first slide plate part disclosed in this invention; Figure 10 This is a schematic diagram of the slide baffle part structure disclosed in this invention.

[0022] Key reference numerals: 1. Top ring; 2. First Hooke hinge base; 3. First accumulator; 4. First nitrogen cylinder; 5. Passive hydraulic cylinder; 6. Clamp; 7. Accumulator mounting base; 8. First Hooke hinge; 9. Tensioner base; 10. Top connector; 11. Riser; 12. Second Hooke hinge base; 13. Second Hooke hinge; 14. Rotary worktable; 15. Cross slide system; 16. Second accumulator; 17. Active hydraulic cylinder; 18. Second nitrogen cylinder; 19. Riser mounting ring; 20. Third 21. Hooke's hinge; 22. Backflush valve oil supply pipe; 23. Oil supply pipe; 24. Rotary worktable pad; 25. First slide pad; 26. Base pad; 27. Slide base; 28. Slide top plate; 29. ​​Movable slide baffle; 30. Movable slide; 31. First built-in rail; 32. Second built-in rail; 33. First slide pad; 34. Second slide pad; 35. Slide rail baffle; 36. Slide baffle; 37. Second slide pad; 38. Fixed platform. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0024] This invention provides a dual-mode interconnected drive simulation device for a liquid-gas composite tensioner, which includes an upright configuration employing "bottom active control simulation + top passive response verification". From bottom to top, the simulation device mainly consists of a translation mechanism for the bottom drilling platform, a rotation adjustment mechanism, a vertical movement and tilting simulation mechanism for the middle drilling platform, a riser 11, and a composite tensioner mechanism at the top.

[0025] Combination Figure 1 , Figures 5-7 , Figures 9-10 As shown, the translation mechanism serves as the base of the simulation device and is designed with a heavy-duty cross slide system 15. This system achieves composite motion of the X and Y axes through layered installation. Specifically, the bottommost first moving unit has several parallel first slide rails, and slide rail baffles 35 are installed at both ends of the first moving unit along the length of the first slide rails for limiting movement. Second moving units are slidably mounted on the first slide rails. The bottom of the second moving unit is slidably connected to the first slide rails via a first slide plate 24, a slide limiter 34, and a second slide plate 37. The slide limiter 34 is installed on the second slide plate 37 to limit the position of the slide.

[0026] The first slide rail has the same structure as the second slide rail, including a base plate 25, a slide base 26 mounted on the base plate 25, and a slide top plate 27 mounted on the top of the base plate 25. This forms a U-shaped groove between the base plate 25 and the slide base 26, and a sliding groove between the U-shaped groove and the slide top plate 27. A movable slide 29 is slidably connected within the sliding groove. The two inner sides of the movable slide 29 are respectively provided with a first built-in rail 30 and a second built-in rail 31. Several movable slide baffles 28 are provided at both ends of the slidably connected guide rails along their length. The bottom of the movable slide 29 is also provided with a first slide pad 32 and a second slide pad 33 to reduce wear on the movable slide 29. Slide baffles 36 are installed at both ends of the first and second slide rails along their length to prevent the movable slide 29 from detaching from the slide rails.

[0027] like Figure 8 As shown, a rotating worktable 23 is connected above the translation mechanism for connecting the rotation adjustment mechanism. The rotation adjustment mechanism carries the hydraulic system above via the rotating worktable 14, driving the entire upper structure to rotate around the vertical centerline, thereby simulating the platform's yaw motion.

[0028] Combination Figures 1 to 4As shown, the core of this simulation device is mounted above the rotating worktable: the platform's vertical movement and tilting simulation mechanism. This mechanism includes a fixed platform 38 at the bottom, on which several active hydraulic cylinders 17 are vertically arranged in a circular array. Each active hydraulic cylinder has a second accumulator 16 mounted externally, and a second nitrogen cylinder 18 that provides high-pressure gas to the second accumulator 16. In this part, the invention employs a unique hydraulic pipeline design: to solve the problems of slow hydraulic response and single-point failure under high-flow conditions, the system abandons the traditional hydraulic pipeline design of "one accumulator supplies only one cylinder," instead combining independent control with joint control. Specifically, each second accumulator 16 is connected to a hydraulic oil supply pipe 22. The supply pipe 22 branches into two lines, each connecting to the high-pressure hydraulic chamber (rodless chamber) of two adjacent actuator hydraulic cylinders. The high-pressure hydraulic chamber of each actuator hydraulic cylinder also simultaneously receives hydraulic oil from two different second accumulators 16 via pipelines. This parallel structure, where "one cylinder connects to two accumulators, and one accumulator supplies two cylinders," allows each hydraulic cylinder to have double the oil inlet and outlet paths simultaneously when performing high-frequency, large-amplitude extension and retraction movements. This significantly improves the hydraulic oil throughput efficiency and eliminates motion lag. Furthermore, if one of the second accumulators 16 fails, the other second accumulators 16 in the network can still provide pressure to the active hydraulic cylinder 17 connected to that accumulator, preventing experimental interruption. Additionally, a solenoid valve with a shut-off function is installed at the connection point between the oil supply pipe 22 and the oil inlet of each active hydraulic cylinder 17. These solenoid valves act as switches controlling the connection between the second accumulator 16 and the active hydraulic cylinder 17. They can flexibly adjust the on / off state between each hydraulic cylinder chamber and the interconnection network according to the experimental task. When the solenoid valves are fully open, the pressure of each power unit is complementary, providing extremely high operational stability and fault tolerance for long-cycle experiments. When the system is switched to an independent control mode of "one accumulator corresponding to one hydraulic cylinder" by closing specific valves, the system can adjust the pressure of the high-pressure hydraulic chamber of each active hydraulic cylinder 17 to extend the piston rod of the actuator cylinder by different lengths. This accurately simulates the different tilting conditions of the platform under different sea conditions, thus obtaining the working data of the tested top ring direct-push hydraulic-gas composite tensioner under different sea conditions, and facilitating subsequent related research. This special connection structure not only enhances the simulation realism of the entire device to the variable deep-sea environment but also significantly expands the testing capability range and control accuracy of the entire simulation experimental device. Each solenoid valve is controlled by a PLC control unit to open or close.

[0029] First, independent control can be achieved by controlling the electromagnetic shut-off valve to be in the closed state via PLC control unit commands: one accumulator corresponds to one hydraulic cylinder. The system can precisely adjust the pressure of each cylinder, driving the piston rod to generate differential displacement, thereby simulating the tilting attitude of an offshore platform under different sea conditions. This innovative structure ensures the comprehensiveness and accuracy of the experimental data of the tested "top ring direct-push hydraulic-gas composite tensioner," significantly improving the simulation realism, testing range, and control precision of the entire device.

[0030] Secondly, by controlling the electromagnetic shut-off valve to be in the open state via PLC control unit commands, combined control can be achieved: one hydraulic cylinder connects to two accumulators, and one accumulator supplies power to two hydraulic cylinders. This hydraulic pipeline network provides each hydraulic cylinder with double the oil flow path during high-frequency lifting and lowering movements, fundamentally solving the industry bottleneck of slow response under high-flow simulation conditions. The hydraulic pipeline structure breaks away from the traditional one-to-one connection, linking multiple hydraulic components together and enabling structural adjustments to the pressure supply pipeline. This ensures that even if a part of the vertical movement and tilting simulation mechanism of the central drilling platform malfunctions, the entire system can still function.

[0031] Specifically, when the second accumulator 16 or its connecting pipeline at a certain location experiences a sudden pressure drop, seal failure, or even pipeline rupture during the experiment, thanks to the hydraulic pipeline design of the present invention (one cylinder connecting two accumulators), the direct-push hydraulic cylinder 17 at the fault location will not experience instantaneous subsidence due to the loss of its original pressure source. This fault-tolerant design structurally avoids riser instability and collision caused by instantaneous pressure loss, as well as damage to the experimental equipment. This ensures that the precision dynamics experiment can remain uninterrupted and continuous in simulating complex sea conditions, significantly improving the reliability of the entire experimental device in maintaining normal operation under abnormal conditions. Simultaneously, the backflow valve oil supply pipe 21 in the pipeline is equipped with an anti-backflow control valve to limit the oil supply rate and prevent backflow impact in the event of system failure.

[0032] Furthermore, in the hydraulic pipeline, a backflow valve oil supply pipe 21 is integrated on the pipeline connecting the active hydraulic cylinder 17 and the second accumulator 16. The backflow valve oil supply pipe has a built-in backflow valve internally integrated to limit the instantaneous backflow speed of the oil, ensuring system safety. All oil supply pipes 22 in the ring array are designed with equal length. By ensuring the consistency of the physical path length, the time difference in hydraulic signal transmission to each actuating hydraulic cylinder is minimized, thereby improving the accuracy of the tilting motion of the multi-cylinder synchronous simulation platform.

[0033] Meanwhile, the top of each active hydraulic cylinder 17 is connected to the riser fixing ring 19 via the third Hooke hinge 20. The riser fixing ring 19 is used to install the vertical riser 11. The top of the riser 11 is connected to the upper composite tensioner mechanism via the top connector 10, which is the passive response system at the top.

[0034] The top connector 10 employs a special mechanical design, primarily composed of a split nut, support ring, installation tool, and flexible body. This design prevents rigid connection breakage while providing both axial tensile strength and compressive rigidity. When the central motion simulation system generates an upward swaying displacement, the cylinder of the top tensioner moves upward synchronously. At this time, the hydraulic oil in the high-pressure hydraulic chamber (pressure chamber) of the passive hydraulic cylinder 5 is squeezed and discharged into the first accumulator 3 through the pipeline, inducing the piston rod to retract upward relative to the cylinder. Conversely, when the bottom motion simulation system is in the descending phase, the passive hydraulic cylinder 5 descends as a whole. Under the pressure of the first accumulator 3, hydraulic oil is injected in reverse into the high-pressure hydraulic chamber (working chamber) of the passive hydraulic cylinder 5, driving the piston rod to extend downward relative to the cylinder. Through this relative motion logic of cylinder follow-up and piston compensation, the top ring direct-acting hydraulic-pneumatic composite tensioner assembly under test can accurately provide constant tension and displacement compensation for the riser under platform fluctuations.

[0035] like Figure 1 As shown, the composite tensioning mechanism includes a tensioner base 9 fixedly connected above the top connector 10. Several second Hooke hinge bases 12 are arranged in a circumferential array on the tensioner base 9 for mounting second Hooke hinges 13. Above the composite tensioner mechanism are several top rings 1 mounted via brackets. Each top ring 1 has a first Hooke hinge base 2 for mounting first Hooke hinges 8. The number and position of the first Hooke hinges 8 correspond one-to-one with the second Hooke hinges 13, and are used to mount passive hydraulic cylinders 5. The supporting column below the top rings 1 is a hollow steel pipe structure, and the inside of the column is filled with high-damping concrete or stone chips to suppress mechanical resonance generated during the experiment.

[0036] The rear cover of the passive hydraulic cylinder 5 is shortly connected to the first Hooke hinge 8, and the piston rod at the movable end is connected to the second Hooke hinge 13 and installed upside down, tilting towards the inner side of the circumferential array from top to bottom. Each passive hydraulic cylinder 5 is equipped with a first nitrogen cylinder 4 and a first accumulator 3 via clamps 6 and accumulator mounting bases 7. The first nitrogen cylinder 4 provides high-pressure gas to the first accumulator 3, thereby providing hydraulic energy to the passive hydraulic cylinder 5. The first accumulator 3 and the first nitrogen cylinder 4 are symmetrically mounted along the circumference of the top ring, and a counterweight balance design counteracts the eccentric torque generated on the frame when the hydraulic cylinder operates.

[0037] This simulation device is designed with reference to the API standard calculation method of the offshore oil industry. It accurately simulates the actual stress on the riser in the sea through a bottom actuator, thereby comprehensively testing the performance of the top tensioner. In the specific simulation process, the bottom active hydraulic cylinder 17 first applies a downward pulling force, according to the formula: T min =(T Srmin ·N) / [R f (Nn)]; In the formula: R f -- indicates the tension coefficient, which is usually between 0.9 and 0.95; T Srmin --Indicates the minimum vertical tension required for the riser to bend on the tensioning ring; N-- indicates the total number of top tensioners; n-- represents the number of items that broke; The dynamic changes in the bottom tension are used to verify whether the remaining tensioner at the top can still hold the riser steady to prevent failure when some tension is lost.

[0038] Meanwhile, in order to reproduce the complex stress state of the riser under the combined action of seawater, mud, and waves, the bottom annular array hydraulic cylinder adjusts the output force in real time according to the top tension formula, which is expressed as follows: T top =T e +W riser -W water +W fluid； In the formula: W riser --The weight of the riser; W fluid --Heavy drilling mud inside the pipe; W water --Seawater buoyancy; T e --Safe over-increase dosage; By varying the load output, both heavy and light, high and low, the stress requirements of risers under different environments can be simulated. Regardless of whether the riser has a buoyancy block, this device can perform targeted dynamic performance tests on the tensioner under test at the top by adjusting the thrust and range of movement at the bottom. It has strong engineering versatility and practical reference value.

[0039] The simulation effect of the simulation device of the present invention will be verified through experiments below: This device adopts an upright configuration, meaning the entire device uses a heavy-duty structure placed at the bottom for stable standing. This design features a low center of gravity and high safety performance, demonstrating extremely high structural stability during various tests. The overall experiment follows the logic of active simulation of motion by the bottom experimental device and passive response feedback by the top tested device. The aim is to study the working capability of the top-ring direct-push liquid-gas composite tensioner under different sea conditions and obtain various data during its operation.

[0040] The first experimental task was to study the effectiveness of the tested liquid-gas composite tensioner in relative motion compensation. The second experimental task was to verify, through a simulation mechanism of vertical movement and tilting of the central drilling platform, whether the tensioner could provide the corresponding force to keep the riser taut and upright in deep sea conditions while filled with silt or other liquids of different densities. The third experimental task was to verify, through a simulation mechanism of vertical movement and tilting of the central drilling platform, whether the tested tensioner had the ability to cope with extreme dangerous situations, such as blowouts, and whether the tensioner could provide sufficient tension to lift the riser as a whole, thereby preventing the riser from colliding with the blowout preventer.

[0041] For the first experimental task, the standard operating procedure is as follows: Based on the specific sea conditions to be simulated, the operator closes one of the valves connecting the oil supply pipe 22 and the active hydraulic cylinder 17 via the control system, thus forming a specific loop connection structure between the single second accumulator 16 and the single active hydraulic cylinder 17. At this time, the multiple active hydraulic cylinders 17 arranged in a ring array can extend and retract to different degrees according to control commands, meeting the conditions for simulating complex sea conditions. The control system issues a command to lift the first part of the active hydraulic cylinders 17, making the lifting height greater than that of the second part of the active hydraulic cylinders 17. The high-pressure hydraulic chamber of the first part of the lifted active hydraulic cylinders 17 draws oil from the second accumulator 16, the piston rod lifts upward, and the force is transmitted to the riser fixing ring 19. The second part of the active hydraulic cylinders 17 also lifts under the control system, making the lifting height of the active hydraulic cylinders 17 lower than that of the first part of the active hydraulic cylinders 17, and the force is transmitted to the riser fixing ring 19. At this point, the riser fixing ring 19 can be tilted differently by varying the lifting height of each active hydraulic cylinder 17, simulating the tilting of the platform under extreme sea conditions and sudden events. Simultaneously, the bottom drilling platform translation mechanism responds, with the bottom motor synchronously driving the moving slide 29 to displace along the fixed track on the slide base 26, physically replicating the platform's horizontal drift on the sea surface—that is, the forward / backward or left / right horizontal displacement caused by wind and waves. Next, the rotating worktable 14 drives the upper mechanism to rotate around the vertical axis, simulating the platform's yaw—that is, the horizontal rotational motion of the platform around its vertical central axis. The tested hydraulic cylinder 5, located below the top ring 1 (which is used to fix the top of the hydraulic cylinder and bear the upward pulling force of the entire system), senses the load and, utilizing its hydraulic-gas composite characteristics, guides hydraulic oil into the first accumulator 3 or the passive hydraulic cylinder 5, thereby causing the tested tensioner to extend or retract to compensate for the riser's movement.

[0042] The second experimental task aims to verify the constant tension maintenance capability and buckling resistance of the tested tensioner under varying fluid density inside the riser or different operating conditions. Specifically, the PLC control unit commands all electromagnetic shut-off valves to be open, switching the vertical movement and tilting simulation mechanism of the central drilling platform to a combined control mode. The parallel pressure self-balancing network formed by each active hydraulic cylinder 17 and the second accumulator 16 ensures the stability of high-load output. The system operates according to the formula: T top =T e +W riser -W water +W fluid .

[0043] In the formula, T top Indicates the tension at the top of the tensioner; T e Indicates the overlift of the bottom assembly of the riser pipe; Wriser W represents the total weight of all risers; water W represents the buoyancy of the riser in seawater; fluid This indicates the weight of the drilling fluid inside the riser.

[0044] The simulated load is calculated in real time, and the active hydraulic cylinder 17 is driven to apply a precise downward dynamic tension to the riser fixing ring 19, thereby reproducing the effective weight change of the riser when filled with drilling mud of different densities, seawater, or when performing different deep-water operations. During this process, the sensors monitor whether the top ring direct-acting hydraulic-pneumatic composite tensioner can respond quickly and provide sufficient compensation tension by utilizing its hydraulic-pneumatic energy storage characteristics, ensuring that the riser 11 always remains taut and upright, and verifying its adaptability to working conditions under complex variable load environments.

[0045] The third experimental task aims to verify the rapid response and emergency recovery capabilities of the tested tensioner under extreme and dangerous conditions such as blowouts, riser breakage, or emergency disconnection (EDS). In practice, the system first drives the active hydraulic cylinder 17 to apply downward tension to simulate the enormous tension load on the riser under normal operating conditions. Then, the control system simulates a "sudden load loss" scenario: instructing the bottom hydraulic circuit to quickly unload or driving the bottom active hydraulic cylinder 17 to retract at high speed in a controlled manner, physically replicating the instantaneous separation of the riser bottom from the subsea wellhead blowout preventer (BOP). At this instant, the system focuses on observing and recording whether the tested liquid-gas composite tensioner at the top can immediately utilize the enormous potential energy stored in the first accumulator 3 to drive the passive hydraulic cylinder 5 to generate sufficient instantaneous upward acceleration and tension, rapidly lifting the entire riser 11 upward and retracting it to a safe stroke range, thereby verifying its ability to prevent secondary collisions between the bottom of the riser and the subsea wellhead device.

[0046] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A dual-mode interconnected drive simulation device for a liquid-gas composite tensioner, characterized in that, It includes: Translation mechanism; Rotary adjustment mechanism: It is mounted on the translation mechanism and is driven by the translation mechanism to move horizontally in the orthogonal direction; Vertical movement and tilting simulation mechanism: includes a fixed platform (38) set on a rotary adjustment mechanism, the fixed platform (38) is driven by the rotary adjustment mechanism to rotate along a vertical axis; a number of active hydraulic cylinders (17) arranged in a circular array are vertically set on the fixed platform (38), the movable end of the active hydraulic cylinder (17) is set upward, the piston rod of each active hydraulic cylinder (17) is connected to a third Hooke hinge (20), and the number of third Hooke hinges (20) converges to connect to the riser fixing ring (19); a second accumulator (16) is connected to each active hydraulic cylinder (17), the number of active hydraulic cylinders (17) is even, the number of active hydraulic cylinders (17) is divided into several linkage units, each linkage unit includes any two adjacent active hydraulic cylinders (17) in the circular array, the rodless chambers of the two active hydraulic cylinders (17) in each linkage unit are connected to the second accumulator (16) through the oil supply pipe (22) to form an interconnected hydraulic pipeline structure; Riser (11): Vertically installed inside riser fixing ring (19); The support has several top rings (1) installed in a ring array on its top. Composite tensioner mechanism: includes tensioner base (9) connected to riser (11) and several passive hydraulic cylinders (5). Several second Hooke hinges (13) are installed in a ring array on tensioner base (9). A first Hooke hinge (8) is installed on each top ring (1). The number and position of the second Hooke hinges (13) correspond one-to-one with the first Hooke hinges (8) and are used to install several passive hydraulic cylinders (5). The rear cover end of the passive hydraulic cylinder (5) is connected to the first Hooke hinge (8), and the piston rod is connected to the second Hooke hinge (13).

2. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: The translation mechanism includes a first moving unit and a second moving unit. The first moving unit is provided with a plurality of parallel first slide rails, and the second moving unit is slidably mounted on the plurality of first slide rails on the first moving unit. The second moving unit is provided with several parallel second slide rails, and a rotating worktable pad (23) is slidably installed on the several second slide rails for installing the rotation adjustment mechanism.

3. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 2, characterized in that: The first slide rail includes a base plate (25) disposed on the first moving unit and a slide base (26) disposed on the base plate (25). The top of the base plate (25) is also provided with a slide top plate (27), thereby forming a slide groove between the base plate (25), the slide base (26) and the slide top plate (27). A movable slide (29) is slidably installed in the slide groove. The movable slide (29) is connected to the second moving unit to drive the second moving unit to translate. The structure of the second slide rail is the same as that of the first slide rail.

4. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 3, characterized in that: The base plate (25) has slide baffles (36) installed at both ends along its length to prevent the movable slide (29) from detaching from the slide groove.

5. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: Each oil pipeline (22) is connected to a solenoid valve, and each solenoid valve is connected to a control unit to control the opening and closing of the solenoid valve in order to switch between linkage mode and independent mode.

6. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: Each second accumulator (16) is connected to its corresponding active hydraulic cylinder (17) via an oil supply pipe (22) and to one of the active hydraulic cylinders (17) adjacent to its corresponding active hydraulic cylinder (17).

7. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: Each passive hydraulic cylinder (5) is equipped with a first accumulator (3) and a first nitrogen cylinder (4). Each first nitrogen cylinder (4) is connected to its corresponding first accumulator (3), and each first accumulator (3) is connected to its corresponding passive hydraulic cylinder (5) to provide hydraulic energy to each passive hydraulic cylinder (5).

8. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: Each active hydraulic cylinder (17) is equipped with a second nitrogen cylinder (18), and several second accumulators (16) are connected to the second nitrogen cylinders (18) respectively to provide hydraulic energy to each active hydraulic cylinder (17).

9. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in claim 1, characterized in that: Each active hydraulic cylinder (17) is also connected to a second accumulator (16) connected thereto via a backflow valve oil supply pipe (21). The backflow valve oil supply pipe (21) is equipped with a backflow valve to limit the oil supply speed and prevent backflow impact when the system fails.

10. The dual-mode interconnected drive simulation device for the liquid-gas composite tensioner as described in any one of claims 1-9, characterized in that: Each passive hydraulic cylinder (5) is inclined from top to bottom toward the inner side of the circumferential array.

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