An offshore construction platform and a design method and a construction method thereof

Abstract

The offshore construction platform provided by the embodiments of the present disclosure, the design method thereof and the construction method thereof comprise a platform main body, a plurality of pile legs arranged circumferentially along the platform main body and a suction pile foundation corresponding to each pile leg; the suction pile foundation comprises a suction pile cylinder; one end of the pile leg is connected with the platform main body, for providing support for the platform main body; the other end of the pile leg is connected with the top of the corresponding suction pile cylinder, and the suction pile cylinder is used for penetrating into the seabed of a construction area and fixing the platform main body. The offshore construction platform provided by the embodiments of the present disclosure has the self-lifting ability and can be moved by towing to a construction position, and the suction pile foundation can penetrate into the seabed, so that the platform can remain stable even in extreme weather conditions, ensuring the smooth progress of the construction operation. The offshore construction platform has strong mobility and adjustability, can be moved to different operation areas for construction operation, and improves the exploration and development efficiency; and due to the mobility, the offshore construction platform can be repeatedly used, further reducing the construction cost.

Description

Technical Field

[0001] This disclosure relates to the field of marine pipeline construction, and in particular to an offshore construction platform and its design and construction methods. Background Technology

[0002] The application of directional drilling technology for marine pipelines is becoming increasingly widespread, offering advantages such as protecting the seabed environment, ensuring pipeline safety, and minimizing impact on shipping traffic. Currently, most marine directional drilling is land-to-sea directional drilling, where the drilling rig is deployed on land, the pipeline begins its ascent from the land, crosses to the target sea area, and emerges from the seabed. Construction vessels then retrieve the pipeline at the exit point for further operations.

[0003] However, due to the increasing number of marine pipelines crossing shipping lanes and intersecting with existing pipelines, sea-to-sea directional drilling is required. This means that both the entry and exit points of the directional drilling are located at sea, necessitating the deployment of directional drilling equipment at sea. However, directional drilling places extremely high demands on the horizontal and vertical bearing capacity of the construction platform. Ordinary floating barges, which rely on anchoring for positioning, suffer from insufficient anchoring force and are significantly affected by wind and waves, making it difficult to meet the required construction efficiency and capacity. Fixed construction platforms are costly and cannot flexibly change the construction location. Summary of the Invention

[0004] This disclosure provides an offshore construction platform and its design and construction methods to address the problems of insufficient anchoring force and significant susceptibility to wind and wave conditions in ordinary floating barges, and the high cost and inflexible construction location of fixed construction platforms.

[0005] Based on the above problems, in a first aspect, the present disclosure provides an offshore construction platform, comprising: a platform body, a plurality of pile legs arranged circumferentially along the platform body, and suction pile foundations corresponding to each pile leg; the suction pile foundations include suction pile cylinders;

[0006] One end of the pile leg is connected to the platform body to provide support for the platform body;

[0007] The other end of the pile leg is connected to the top of the corresponding suction pile cylinder, which is used to penetrate the seabed of the construction area and fix the main body of the platform.

[0008] In conjunction with the first aspect, in one possible implementation, the offshore construction platform further includes: a lifting system for each leg; the lifting system includes: a transmission device and a locking device, the transmission device including a drive device, a gear and a rack disposed inside the platform body and disposed on the leg; the locking device including a pin disposed inside the platform body and a hole disposed on the leg.

[0009] The lifting system is used to drive the gear to rotate in the corresponding adjustment direction through the drive device when the height of the platform body needs to be adjusted, and to drive the pile leg to move through the rack, so that the platform body moves in the target direction until it stops moving at the target position, and inserts the pin into the socket on the pile leg corresponding to the position of the pin.

[0010] In conjunction with the first aspect, in one possible implementation, the offshore construction platform further includes: a suction pump;

[0011] The suction pump is connected to the top of the suction pile cylinder and is used to extract water from the suction pile cylinder during the process of driving the suction pile cylinder into the seabed; and to inject water into the suction pile cylinder during the process of pulling the suction pile cylinder out of the seabed; and / or

[0012] The top of the suction pile cylinder is provided with a manhole and a drainage hole, the drainage hole being used to discharge water pumped out by the suction pump; and / or

[0013] The construction platform also includes a ballast system installed inside the main body of the platform.

[0014] In conjunction with the first aspect, in one possible implementation, the offshore construction platform further includes: a pile driving system;

[0015] The pile driving system includes: a pile driving water pump, a pile driving nozzle, a pile driving pipeline, and a surfactant storage tank;

[0016] The pile driving nozzle is located at the top of the suction pile cylinder and the bottom of the pile leg; one end of the pile driving pipeline is connected to the pile driving water pump, and the other end is connected to the pile driving nozzle; the surfactant storage tank is connected to the pile driving water pump; the pile driving water pump is used to draw in seawater, mix the seawater with the surfactant to form a pile driving fluid, and pressurize and pump the pile driving fluid into the pile driving pipeline.

[0017] In conjunction with the first aspect, in one possible implementation, the platform body further includes: functional modules and supporting modules, and a deck;

[0018] The functional module and supporting module are fixedly connected to the upper surface of the deck;

[0019] The functional modules and supporting modules include at least one of the following: directional drilling rig module, directional drilling control module, power module, drill rod stacking area, office module, mud material storage area, and construction platform crane.

[0020] Secondly, embodiments of this disclosure provide a method for designing an offshore construction platform based on the offshore construction platform described in the first aspect; including:

[0021] Obtain the design basis; the design basis includes engineering geology, hydrological data, operational capabilities, and operational environment requirements.

[0022] Based on the requirements of the operating capacity and operating environment, the weight and dimensions of each piece of equipment are determined;

[0023] Obtain the equipment parameters of each device, and based on the equipment parameters, determine the overall layout of the platform and perform weight and center of gravity analysis;

[0024] Based on the overall layout, the main structure design and compartment division of the platform are determined;

[0025] Based on the marine environment conditions of the platform operation area, the main platform structure and the weight of each piece of equipment, the pile leg structure was determined.

[0026] The structure of the lifting system is determined based on the main dimensions of the platform, the leg structure, and the total weight of each piece of equipment.

[0027] Determine the structural strength of the platform body under towing operations, operational conditions, and storm self-sustaining conditions, and output the load and bending moment at the foundation.

[0028] Based on the platform's main structure, pile leg structure, and in-situ analysis output data, the suction pile foundation structure and the percussion pile system structure are determined.

[0029] Based on the design of the main structure of the platform, the division of the compartments, the leg structure, the structure of the lifting system, the suction pile foundation structure and the pile driving system structure, the design scheme of the target offshore construction platform is obtained.

[0030] In conjunction with the second aspect, in one possible implementation, determining the weight and dimensions of each piece of equipment based on the operational capabilities and operational environment requirements includes:

[0031] Based on the requirements of the operational capabilities and the operational environment, the equipment operational capability parameters are determined; wherein, the operational capabilities include: the target operational pipeline length and the target operational pipeline diameter; the operational environment includes: the operational sea area depth and the operational sea area geological parameters;

[0032] Based on the equipment's working capacity parameters, the weight and dimensions of the construction equipment are obtained; wherein, the construction equipment includes: a drilling rig module; the auxiliary equipment includes at least one of the following: a directional drilling control module, a power module, a drill rod stacking area, and an office module;

[0033] The weight and dimensions of the auxiliary equipment are obtained based on the weight and dimensions of the construction equipment.

[0034] In conjunction with the second aspect, in one possible implementation, determining the leg structure based on the marine environmental conditions of the platform's operation area, the main platform structure, and the weight of each piece of equipment includes:

[0035] The length of the pile leg is determined based on the marine environmental conditions of the platform's operating area;

[0036] Based on the main platform structure and the weight of each piece of equipment, the number and location of the pile legs are determined;

[0037] Based on the length, number, location, and maximum load of the pile legs, the cross-sectional dimensions of the pile legs are obtained; wherein, the maximum load includes the maximum weight of the platform body and the total weight of all equipment.

[0038] Thirdly, embodiments of this disclosure provide a method for constructing an offshore construction platform based on the offshore construction platform described in the first aspect; including:

[0039] After receiving the penetration command, the suction pile system starts the suction pump to extract the seawater inside the suction pile cylinder; under the action of negative pressure, the suction pile cylinder penetrates into the seabed; after the suction pile cylinder reaches the preset penetration depth, the lifting system raises the main body of the platform, so that its air gap height reaches the preset height, and the locking device locks it; the suction pile penetration operation is completed.

[0040] After receiving the pile extraction command, the pile flushing system starts the pile flushing water pump and uses flushing fluid to strip away the mud and sand near the pile shoe of the suction pile, expanding the upward channel of the suction pile. After receiving the penetration command, the lifting system unlocks the locking device and lowers the main body of the platform to the sea surface to provide buoyancy. After receiving the penetration command, the suction pile system starts the suction pump, injects water into the suction pile, and then the lifting system raises the pile legs to pull the suction pile from the seabed, thus completing the suction pile extraction operation.

[0041] In conjunction with the third aspect, in one possible implementation, the construction method further includes:

[0042] During the suction pile driving operation, at least one of the following adjustments are made to control the tilt angle of the construction platform: the driving sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump.

[0043] During the extraction of the suction pile, at least one of the following adjustments is made to control the tilt angle of the construction platform: the extraction sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump.

[0044] The beneficial effects of the embodiments disclosed herein include:

[0045] This disclosure provides an offshore construction platform and its design and construction methods, comprising: a platform body, multiple legs arranged circumferentially along the platform body, and suction pile foundations corresponding to each leg; the suction pile foundation includes a suction pile cylinder; one end of each leg is connected to the platform body to provide support; the other end of each leg is connected to the top of the corresponding suction pile cylinder, which is used to penetrate the seabed of the construction area to fix the platform body. In this embodiment, the offshore construction platform uses suction piles as its foundation, giving it self-elevating capability and allowing it to be towed to a new construction location. During lifting and lowering, it maintains stability, reduces the risk of accidents, and ensures the safety of personnel and equipment. The suction pile foundation can penetrate the seabed, providing stable support and ensuring the platform remains stable even under extreme weather conditions such as storms. Compared to floating barge construction platforms, the offshore construction platform provided in this disclosure can adapt to different marine environments, including rough sea conditions such as waves and storms, ensuring the smooth progress of construction operations. Compared with fixed offshore construction platforms, the offshore construction platform provided in this disclosure has strong mobility and adjustability, can be quickly moved to different work areas for construction operations, and can adapt to different work environments, thereby improving the efficiency of exploration and development; and due to its mobility, it can be reused, further reducing construction costs. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the planar structure of the offshore construction platform provided in an embodiment of this disclosure;

[0047] Figure 2 This is a schematic diagram of the elevation structure of an offshore construction platform provided in an embodiment of this disclosure;

[0048] Figure 3 This is a schematic diagram of the offshore construction platform design method provided in the embodiments of this disclosure;

[0049] Figure 4 This is a schematic diagram of the design process of an offshore construction platform provided in an embodiment of the present disclosure;

[0050] Figure 5 This is a schematic diagram of the construction process of an offshore construction platform provided in an embodiment of this disclosure. Detailed Implementation

[0051] This disclosure provides an offshore construction platform and its design and construction methods. Preferred embodiments of this disclosure are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of this disclosure. Furthermore, the embodiments and features described herein can be combined with each other unless otherwise specified.

[0052] This disclosure provides an embodiment of an offshore construction platform, such as... Figure 1 and Figure 2 As shown, it includes: a platform body 1, multiple pile legs 2 arranged along the circumference of the platform body, and suction pile foundations 3 arranged for each pile leg. The suction pile foundation includes a suction pile cylinder 301.

[0053] One end of the pile leg 2 is connected to the platform body 1 to provide support for the platform body 1;

[0054] The other end of the pile leg 2 is connected to the top of the corresponding suction pile cylinder 301, which is used to penetrate the seabed of the construction area and fix the platform body 1.

[0055] In this embodiment, the offshore construction platform can be towed using external power, such as a tugboat. The platform's main body has a closed bottom structure, allowing it to float on the sea surface using its own buoyancy and be towed to the intended construction area by external power.

[0056] The suction pile foundation 3 is a foundation structure that relies primarily on negative pressure for installation. By creating negative pressure within the suction pile cylinder 301, the cylinder is driven into the seabed until the designed depth is reached, thus securing the suction pile foundation 3 and the entire offshore construction platform. The suction pile foundation provides sufficient anchoring capacity for the offshore construction platform. Compared to floating barge construction platforms in related technologies, the offshore construction platform provided in this embodiment is more stable during operation, has stronger resistance to harsh sea conditions, and improves the efficiency and safety of directional drilling operations. Simultaneously, the suction pile foundation 3 can be pulled out of the seabed, releasing the offshore construction platform from its fixed state, allowing it to be flexibly moved to different construction areas for operation, further improving the efficiency of marine directional drilling operations.

[0057] The offshore construction platform has multiple legs 2. During construction operations, the legs 2 can be lowered to the seabed, and the suction pile foundations 3 at the bottom of the legs 2 are driven into the seabed to secure the offshore platform. The number and length of the legs 2 can be determined according to the marine environment and construction requirements of the construction area.

[0058] In yet another embodiment provided in this disclosure, such as Figure 2 As shown, the offshore construction platform also includes: a lifting system 4 for each leg; the lifting system 4 includes: a transmission device and a locking device, the transmission device including a drive device, gears and racks installed inside the platform body; the locking device including a pin installed inside the platform body and a socket 201 installed in the leg.

[0059] The lifting system 4 is used to drive the gear to rotate in the corresponding adjustment direction when the height of the platform body 1 needs to be adjusted, and to drive the pile leg 2 to move in the direction of adjustment through the rack, so that the platform body 1 moves in the target direction until it stops moving at the target position, and inserts the pin into the socket 201 on the pile leg 2 corresponding to the position of the pin.

[0060] In this embodiment, the lifting system 4 is used to raise or lower the pile legs 2, enabling the switching between construction and towing states. The transmission device of the lifting system 4 drives the lifting of the platform body, and its lifting capacity is determined according to the weight of the platform body 1. The drive device can be driven by a motor or a hydraulic system. The drive device drives the gear to rotate, and the gear drives the rack to move in the vertical direction, thereby causing the pile legs 2 to move vertically relative to the platform. The locking device can be a pin type. When the pile legs 2 are moved into position, the pin inside the platform body is inserted into the insertion hole 201 of the pile legs, thereby locking the position of the platform body in the vertical direction.

[0061] In yet another embodiment provided in this disclosure, the offshore construction platform further includes: a suction pump;

[0062] A suction pump is connected to the top of the suction pile cylinder 301 and is used to extract water from the suction pile cylinder 301 during the process of driving the suction pile cylinder 301 into the seabed; and to inject water into the suction pile cylinder during the process of pulling the suction pile cylinder 301 out of the seabed; and / or

[0063] The top of the suction pile cylinder 301 is equipped with a manhole and a drainage hole, the drainage hole being used to discharge water pumped out by the suction pump; and / or

[0064] The offshore construction platform also includes a ballast system 101 installed inside the main body of the platform 1.

[0065] In this embodiment, a suction pump is disposed at the top of the suction pile cylinder 301. When the suction pile cylinder 301 needs to be driven into the seabed, it is used to pump out the water inside the suction pile cylinder 301, so that the pressure inside the cylinder is lower than the pressure outside the cylinder, and the suction pile cylinder 301 is driven into the seabed by the pressure of the seawater. When the suction pile cylinder 301 needs to be pulled out of the seabed, it is used to pump seawater into the suction pile cylinder 301 to balance the pressure inside and outside the suction pile cylinder 301, making it easier to pull out of the seabed.

[0066] The manhole at the top of the suction pile cylinder 301 is used to facilitate personnel access during the maintenance or cleaning of the suction pile cylinder 301.

[0067] The ballast system 101 inside the platform body 1 is used to adjust the platform ballast by sucking in or expelling seawater. During the process of driving the suction pile cylinder 301 into the seabed, the ballast system 101 sucks in seawater to increase the weight of the offshore construction platform, thereby increasing the vertical pressure on the suction pile cylinder 301 and driving it deeper into the seabed, thus increasing the stability of the offshore construction platform. During the process of pulling the suction pile cylinder 301 out of the seabed, the platform body descends to the sea surface and expels the seawater from the ballast system 101. The platform body provides buoyancy to the entire system, and the buoyancy increases the upward force on the suction pile cylinder 301, making it easier to pull the suction pile cylinder 301 out of the seabed.

[0068] During towing, the ballast system 101 can be adjusted according to the sea conditions. In severe sea conditions, the load on the ballast system 101 can be appropriately increased to improve the stability of the platform during towing.

[0069] In yet another embodiment provided in this disclosure, the offshore construction platform further includes: a pile driving system;

[0070] The pile driving system includes: a pile driving water pump, a pile driving nozzle 5, a pile driving pipeline, and a surfactant storage tank;

[0071] The pile driving nozzle 5 is located at the top of the suction pile cylinder 301 and the bottom of the pile leg 2; one end of the pile driving pipeline is connected to the pile driving water pump, and the other end is connected to the pile driving nozzle 5; the surfactant storage tank is connected to the pile driving water pump; the pile driving water pump is used to draw in seawater, mix the seawater with the surfactant to form the pile driving fluid, and pressurize the pile driving fluid to pump the pile driving pipeline.

[0072] In this embodiment, the pile driving pipeline is connected to a pile driving water pump located on the platform body and is arranged inside the pile leg 2. The pile driving system is used to disperse the silt attached to the suction pile cylinder 301 during the process of pulling the suction pile cylinder 301 out of the seabed using high-pressure water flow, making the process of pulling the suction pile cylinder 301 out of the seabed smoother. During the process of pulling the suction pile cylinder 301 out of the seabed, the pressure of the high-pressure water flow can be periodically adjusted to accelerate the hydration and peeling of the silt attached to the suction pile cylinder 301, thereby reducing the resistance of the silt in the seabed to the extraction process of the suction pile cylinder 301. During the pile driving operation, surfactants can be mixed into the high-pressure water flow to more effectively disperse the silt in the water, expand the rising channel of the suction pile foundation, and lubricate the longitudinal stratum cross section, thereby improving the pile driving efficiency.

[0073] In yet another embodiment provided in this disclosure, such as Figure 1 As shown, the main body of the platform also includes: functional modules and supporting modules and deck 102;

[0074] The functional modules and supporting modules are fixedly connected to the upper surface of the deck;

[0075] The functional modules and supporting modules include at least one of the following: directional drilling rig module 103, directional drilling control module 104, power module 105, drill rod stacking area 106, office module 107, mud material storage area 108, and construction platform crane 109.

[0076] In this embodiment of the disclosure, the construction equipment is fixed on the deck, and a support frame is arranged below the deck, which bears the load of the entire deck and all equipment.

[0077] The directional drilling rig module 103 is the core of the entire offshore construction platform's construction operations, and the directional drilling rig's construction capacity needs to be determined according to the operational requirements.

[0078] The directional drilling directional control module 104 is used to control the drilling direction of the directional drilling rig module. This is achieved through directional tools and measuring instruments. The directional tools adjust the drill bit direction based on real-time measured direction information, and the measuring instruments monitor the drill bit position and direction in real time to ensure the accuracy and safety of directional drilling construction.

[0079] The power module 105 is used to provide power to the drill bit of the directional drilling rig module 103, transmit the rotational power to the drill bit, and support the drill bit in directional drilling operations.

[0080] Drill pipe stacking area 106 is a centralized area for storing drill pipes used in construction. The size of this area is determined based on the target pipeline length of the directional drilling operation.

[0081] Office module 107 is the area for staff to work and live, and its size is determined according to the number of staff stationed on the platform.

[0082] Mud material storage area 108 collects mud returned from the borehole during construction, processes it, and then pumps it into the storage tank for recycling.

[0083] This disclosure provides a design method for an offshore construction platform, such as... Figure 3 As shown, it includes:

[0084] S601. Obtain the design basis; the design basis includes engineering geology, hydrological data, operational capabilities, and operational environment requirements.

[0085] S602. Determine the weight and dimensions of each piece of equipment based on the requirements of operational capacity and operating environment;

[0086] S603. Obtain the equipment parameters of each device, and based on the equipment parameters, determine the overall layout of the platform body and perform weight center of gravity analysis;

[0087] S604. Based on the overall layout, determine the main structure design and compartment division of the platform;

[0088] S605. Based on the marine environmental conditions of the platform operation area, the main platform structure and the weight of each piece of equipment, determine the pile leg structure;

[0089] S606. Based on the main dimensions of the platform, the structure of the pile legs, and the total weight of each piece of equipment, determine the structure of the lifting system;

[0090] S607. Determine the structural strength of the platform body under towing operations, working conditions, and storm self-sustaining conditions, and output the load and bending moment at the foundation.

[0091] S608. Based on the platform's main structure, pile leg structure, and in-situ analysis output data, determine the suction pile foundation structure and the percussion pile system structure.

[0092] S609. Based on the design of the main structure of the platform, the division of the compartments, the leg structure, the structure of the lifting system, the suction pile foundation structure and the pile driving system structure, the design scheme of the target offshore construction platform is obtained.

[0093] In this embodiment of the disclosure, the executing entity may be a computer system with design and simulation functions. The computer system can obtain the engineering geological and hydrological data of the corresponding sea area based on the input construction location, operation capability and operation environment requirements; and use the obtained engineering geological, hydrological data, operation capability and operation environment requirements to execute the design process and output the design scheme of the target offshore construction platform.

[0094] In this embodiment of the disclosure, during the design process of the offshore construction platform, the computer system first needs to obtain information about the target construction sea area (i.e., the location of the directional drilling entry point). This engineering geology may include data such as seabed strata parameters. These seabed strata parameters include physical properties of the seabed strata, such as porosity, permeability, and cohesion. These physical parameters reflect the frictional forces experienced by the drilling rig as it penetrates the seabed during construction. Seabed strata parameters can be obtained from a marine information database.

[0095] Operational capabilities can include: the length of the directional drilling work area, the drilling depth, etc. The required drill pipe length can be determined based on the length of the directional drilling work area and the drilling depth.

[0096] The operational environment requirements may include: the weather conditions and sea ice conditions of the target sea area during the operation period, and the determination of the maximum load that the offshore construction platform may encounter based on the weather conditions, sea ice conditions and wave conditions, and the determination of the structure of the offshore construction platform.

[0097] In one possible implementation, step S603 can be implemented as follows: Based on the marine directional drilling operation process, a preliminary arrangement is made of the drilling rig module, directional drilling control module, power module, and drill pipe stacking area, taking into account the weight and required area, combined with the operation process and safety distance requirements. The drilling rig module can be located on the side of the platform near the subsea pipeline entry point, close to the center of the platform; the drilling rig module should maintain a safe distance from other adjacent modules; the drill pipe stacking area can be located on the side of the platform near the crane for easy hoisting and stacking; the directional drilling control module and power module are adjacent to the drilling rig module.

[0098] Furthermore, considering the safety and efficiency of construction operations, supporting modules such as office modules are arranged. The office modules can be placed on the side of the ship away from the stacking area and drilling rig operation area, maintaining a safe distance from the construction modules.

[0099] After completing the initial layout, based on the module weights in the weight and dimension statistics table and the positions of each module, the weight distribution of the platform's main body was analyzed and calculated. The layout of the functional modules was then optimized and adjusted. Without violating safety regulations, the arrangement of the offshore construction platform's main body was adjusted so that the center of gravity of the platform's superstructure was located near the main body's centerline, resulting in a balanced overall weight distribution.

[0100] In one possible implementation, step S604 can be performed as follows: The platform is divided into compartments based on construction needs, ballast requirements, and stability requirements. Trusses and structural members are uniformly arranged according to the weight distribution of the main body of the offshore construction platform, the compartment division, and the deck load. Stress concentration areas are identified through structural analysis, and trusses and structural members are added and adjusted accordingly to strengthen local structures. This yields the final platform structure and compartment division.

[0101] In one possible implementation, step S606 can be performed as follows: Based on the technical requirements of the lifting system under different construction conditions, and considering loads such as the platform's main body weight, module system weight, and construction loads, calculate the minimum lifting weight of the lifting system; based on the minimum lifting weight and the number of pile legs, and taking redundancy into account, obtain the design lifting weight; and complete the selection and design of the lifting system based on the design lifting weight.

[0102] In one possible implementation, step S607 can be performed as follows: analyzing the construction conditions of the offshore construction platform, which may include: towing operation condition, operational condition, and storm self-sustaining condition. For the towing operation condition, based on the platform characteristics under towing conditions, the towing stability and structural strength of the pile legs are checked when the pile legs are retracted (i.e., the pile legs are raised to their maximum height by the lifting system) and the offshore construction platform is towed at sea by external power. For the operational condition, based on the platform characteristics under operational conditions, the structural strength of the platform body and pile legs is checked under the influence of its own weight, environmental conditions, and drilling rig loads after the suction pile cylinder has fully penetrated the seabed and the directional drilling rig performs the preset construction task, thus determining the load and bending moment borne by the suction pile foundation. For the storm self-sustaining condition, based on harsh environmental conditions and the cessation of directional drilling operations, the structural strength of the offshore construction platform body and pile legs is checked, thus determining the load and bending moment borne by the suction pile foundation.

[0103] In one possible implementation, step S608 can be performed as follows:

[0104] Step 1: Determine the foundation dimensions of the suction piles. Based on the maximum load and bending moment experienced by the suction pile foundation in step S607 above, obtain parameters such as the diameter of the suction pile cylinder, the target penetration depth of the suction pile cylinder, the wall thickness, spacing, and installation method. A pile shoe is also installed at the top of the suction pile foundation to ensure platform stability. The wall thickness of the suction piles can be calculated using the diameter of the suction pile cylinder, and the minimum wall thickness... In the formula: t is the wall thickness of the suction pile; D S The diameter of the suction pile cylinder is denoted as .

[0105] Step 2: Determine the penetration depth of the suction pile cylinder. Based on the engineering geological conditions of the operating sea area, determine the initial depth at which the suction pile cylinder can penetrate the seabed of the operating sea area using only the load of the offshore construction platform. Then, based on the calculated values ​​of the seabed bearing capacity and the pull-out force of the lifting system, and combined with the safety factor, determine the penetration depth that can ensure the stability of the offshore construction platform and the normal extraction of the suction pile cylinder by the lifting system.

[0106] Step 3: Penetration Feasibility Analysis. Analyze the relationship between the critical suction, allowable suction, and required suction of the suction pile foundation in the seabed soil layer of the operating area, and calculate the operating power of the suction pump. Based on the operating power of the suction pump, select a suction pump with suction power sufficient to penetrate the suction pile cylinder to the specified depth.

[0107] Step 4: Bearing Capacity and Stability Verification. Verify the bearing capacity and stability under various operating conditions, including operational conditions, storm self-sustaining conditions, suction pile penetration conditions, pile extraction conditions, and towing conditions. Bearing capacity verification includes assessing the resistance of the system comprised of the seabed soil and suction pile foundation to loads transferred to the superstructure of the offshore construction platform. Stability verification includes assessing the strength and stability of the suction pile foundation itself under different operating conditions.

[0108] Furthermore, to reduce the resistance to pile extraction, the suction pile foundation is equipped with a pile driving system. The selection of the pile driving system and the design of the nozzle layout are completed based on the characteristics of the suction pile penetration depth and the seabed soil of the operating area.

[0109] In one possible implementation, step S609 can be performed as follows: based on the stress relationship between the platform body, the legs, and the suction pile foundation, structural optimization of the main structure, legs, and suction pile foundation is carried out. Stress analysis is performed on local structures in stress concentration areas such as the connection between the platform body and the legs, and the connection between the legs and the suction pile foundation. Based on the stress analysis results, the aforementioned local structures are adjusted to ultimately complete the offshore construction platform design and obtain the target offshore construction platform design scheme.

[0110] Based on the above steps, the offshore operation platform design method provided in this disclosure, in one possible implementation, can be implemented as follows: Figure 4 The design process for offshore operation platforms is shown.

[0111] In another embodiment provided in this disclosure, the above step S602, "determining the weight and dimensions of each piece of equipment based on the requirements of operational capabilities and the working environment," can be implemented as follows:

[0112] Step 1: Determine the equipment's operational capability parameters based on the requirements of operational capacity and the operational environment; operational capacity includes: target operational pipeline length and target operational pipeline diameter; operational environment includes: operational sea area depth and operational sea area geological parameters.

[0113] Step 2: Based on the equipment's working capacity parameters, obtain the weight and dimensions of the construction equipment; wherein, the construction equipment includes: a drilling rig module; the auxiliary equipment includes at least one of the following: a directional drilling control module, a power module, a drill pipe stacking area, and an office module.

[0114] Step 3: Based on the weight and dimensions of the construction equipment, obtain the weight and dimensions of the auxiliary equipment;

[0115] In this embodiment of the disclosure, based on the needs of the construction operation, parameters such as the depth H of the operating sea area, the geological parameters G of the operating sea area, the length L of the target operating pipeline, and the diameter D of the target operating pipeline are obtained for the directional drilling operation area. The required drilling capacity parameter K is obtained by the following drilling capacity calculation formula (1).

[0116] K=L*π*d*f(G)*α (1)

[0117] Wherein, α is the safety risk coefficient, which should be greater than 1 to ensure construction safety. The larger the safety risk coefficient, the greater the safety redundancy of the selected drilling rig. f(G) is the frictional load calculated based on the formation parameter G, which characterizes the frictional load experienced by the directional drilling bit in the seabed of the construction area.

[0118] Based on the drilling rig's capacity parameters, the required drilling rig modules are selected. Based on the control system and corresponding power requirements of the drilling rig modules, the technical selection of the directional drilling control module and power module is completed. Based on the submarine pipeline crossing distance L and pipeline diameter D, the design of the drill pipe stacking area is completed. Based on the on-site needs of construction personnel, vessel operators, inspection personnel, and other parties necessary for construction, the design of the office module is completed. The module weight and dimensional parameters of the above modules are clarified, and the weight and dimensions of each piece of equipment are determined.

[0119] In another embodiment provided in this disclosure, step S605 above, "determining the leg structure based on the marine environmental conditions of the platform operation area, the main platform structure, and the weight of each piece of equipment," can be implemented as follows:

[0120] Step 1: Determine the length of the pile legs based on the environmental conditions of the sea area where the platform is operating;

[0121] Step 2: Based on the main platform structure and the weight of each piece of equipment, determine the number and location of the pile legs;

[0122] Step 3: Based on the length of the pile legs, the number of pile legs, the location of the pile legs, and the maximum load, obtain the cross-sectional structural dimensions of the pile legs; wherein, the maximum load includes: the maximum weight of the platform body and the total weight of all equipment.

[0123] In this embodiment, based on the overall layout of the platform obtained in step S603 above and combined with the environmental conditions of the work area, the required parameters for the construction platform, such as the dimensions, number, location, and spacing of the pile legs, are initially determined. The load on each pile leg is analyzed, and the load on the pile legs is balanced by adjusting the equipment and pile leg positions. The spacing of the pile legs is adjusted so that the center of gravity of the platform and the centroid of the pile legs are basically coincident, allowing the load of the entire platform to be evenly distributed on each pile leg, which is beneficial to the stress stability of the pile legs.

[0124] Furthermore, the leg length is determined based on factors such as the water depth of the proposed operating area, the required air gap height, the platform depth, the pile driving depth, and the allowance. Leg length L s =H S +S+H P +D+γ, where H SWhere S is the water depth of the operating area, S is the air gap height representing the vertical distance between the deck of the offshore construction platform and the sea surface, and H is the depth of the operating area. P γ represents the height of the offshore construction platform, D represents the depth of the suction pile cylinder penetrating the seabed, and γ represents the redundancy reserved for safety factors and extreme situations.

[0125] The influence of shear deformation on the pile leg was calculated using beam theory, and the cross-sectional dimensions of the pile leg were initially determined. Further, a finite element model of the pile leg was built in the simulation system, and preset loads were applied to the model. These preset loads included vertical loads from the platform body, the weight of various equipment, and the lifting system; horizontal loads from the marine environment; and construction loads under different construction conditions. Construction loads included the loads exerted on the pile leg by construction operations during the construction of the offshore platform. By analyzing the stress state of the pile leg finite element model, the diameter and wall thickness of the pile leg cross-section were adjusted accordingly. Reinforcing trusses and supporting structures were added inside the pile leg cylinder until the stress state of the finite element model met the target performance. Finally, the target pile leg finite element model was obtained, and the pile leg design was completed based on its parameters.

[0126] This disclosure provides a construction method for an offshore construction platform, such as... Figure 5 As shown, it includes:

[0127] After receiving the penetration command, the suction pile system starts the suction pump to extract the seawater inside the suction pile cylinder; under the action of negative pressure, the suction pile cylinder penetrates into the seabed; after the suction pile cylinder reaches the preset penetration depth, the lifting system raises the main body of the platform, so that its air gap height reaches the preset height, and the locking device locks it; the suction pile penetration operation is completed.

[0128] After receiving the pile extraction command, the pile flushing system starts the pile flushing water pump and uses flushing fluid to strip away the mud and sand near the pile shoe of the suction pile, widening the upward channel of the suction pile. After receiving the penetration command, the lifting system unlocks the locking device and lowers the main body of the platform to the sea surface to provide buoyancy. After receiving the penetration command, the suction pile system starts the suction pump, injects water into the suction pile, and then the lifting system raises the pile legs to pull the suction pile from the seabed, completing the suction pile extraction operation.

[0129] In this embodiment, the executing entity can be a computer system on an offshore construction platform with control, detection, monitoring, and judgment functions. This computer system can determine whether the offshore construction platform has reached the predetermined construction position based on detected positioning data; and determine whether corresponding operations can be performed based on detected sea state and weather information; it can also control the lifting system, suction pump, and ballast system to perform corresponding operations based on command information; and simultaneously monitor the status of the offshore construction platform, adjusting the lifting system, suction pump, and ballast system according to the platform's status. The suction pile system can be a device including suction pile foundations and a suction pump, capable of executing penetration and extraction commands, and controlling the suction pile foundation and suction pump according to the commands.

[0130] In this embodiment of the disclosure, the offshore construction platform is towed to the target construction sea area by external power in towing mode. During this process, the offshore construction platform can adjust the load of the ballast system inside the platform according to different sea conditions, so that the offshore construction platform is in a stable towing state.

[0131] Furthermore, once the offshore construction platform arrives at the work area, and if the sea conditions and weather conditions in the work area meet the requirements for carrying out construction operations, the offshore construction platform issues a penetration command, and all equipment on the offshore construction platform enters the penetration operation process.

[0132] The offshore construction platform's lifting system slowly lowers the pile legs, bringing the suction pile foundation closer to the seabed. When the bottom of the suction pile foundation reaches a preset distance from the seabed, the lifting system stops lowering the pile legs. The suction pile system then executes the penetration command, activating the suction pump connected to the top of the suction pile cylinder to extract seawater from inside the cylinder. The lifting system continues to descend, and under the combined action of negative pressure and the lifting system, the suction pile cylinder penetrates into the seabed.

[0133] Furthermore, once the suction pile has penetrated to the preset depth, the suction pump stops operating, and the lifting system raises the platform body, maintaining a certain distance from the sea level. This distance is determined by the air gap height of the operating area. After the platform body reaches the preset height, the lifting system uses a locking device to lock the platform body at that height. After completing the above operations, directional drilling operations for offshore pipelines can begin.

[0134] Furthermore, when the offshore construction platform needs to leave the sea area, it issues a pile extraction command, and all equipment on the platform enters the pile extraction operation process. Based on engineering geological data, the performance of the lifting system, and hull parameters, the required pile extraction force is initially calculated. After the offshore construction platform enters the pile extraction operation, the pile flushing system executes the extraction operation, activating the pile flushing water pump to purge the suction pile cylinder until the manhole and drainage outlet at the top of the suction pile cylinder are fully exposed and not covered by seabed silt. Simultaneously, the high-pressure water flow provided by the pile flushing water pump flushes the soil around the suction pile foundation shoe, widening the upward channel of the suction pile cylinder. According to the pile flushing command, the lifting system unlocks the locking device, adjusts the lifting system of the construction platform to lower the platform body to the sea surface, and adjusts the ballast system to provide buoyancy for the pile extraction process. The suction pile system activates the suction pump to inject water into the suction pile cylinder. Under the combined action of the lifting system and the suction pile system, the suction pile cylinder is gradually pulled out of the seabed by the lifting system.

[0135] Furthermore, the ballast system and lifting system of the construction platform are adjusted to towing mode, and the platform is towed to the next location.

[0136] In another embodiment provided in this disclosure, the construction method for the offshore construction platform further includes:

[0137] During the suction pile driving operation, at least one of the following adjustments shall be made to control the inclination angle of the construction platform: the driving sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump;

[0138] During the extraction of suction piles, at least one of the following adjustments shall be made to control the tilt angle of the construction platform: the extraction sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump.

[0139] In this embodiment, the tilt angle of the offshore construction platform can be monitored by sensors pre-installed on the platform. During the penetration or extraction of the suction pile cylinder into the seabed, the operating power of the lifting system and suction pump is adjusted in real time by monitoring the tilt angle of the offshore construction platform to ensure that the construction platform remains level. Furthermore, a pre-defined sequence for the penetration or extraction of the suction pile cylinder can be used to maintain the levelness of the offshore construction platform.

[0140] Optionally, the preset driving sequence of the suction pile cylinder can be implemented as follows: driving them in one by one in a diagonal order or driving two suction piles on the diagonal simultaneously. The preset extraction sequence of the suction pile cylinder can be implemented as follows: extracting them one by one in a diagonal order or extracting a pair of suction piles on the diagonal simultaneously.

[0141] Through the above description of the embodiments, those skilled in the art can clearly understand that the embodiments of this disclosure can be implemented in hardware or by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solutions of the embodiments of this disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, external hard drive, etc.) and includes several instructions to cause a computer device (such as a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments of this disclosure.

[0142] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the modules or processes in the drawings are not necessarily essential for implementing this disclosure.

[0143] Those skilled in the art will understand that the modules in the apparatus of the embodiments can be distributed in the apparatus of the embodiments as described in the embodiments, or they can be located in one or more devices different from this embodiment with corresponding changes. The modules of the above embodiments can be combined into one module, or they can be further divided into multiple sub-modules.

[0144] The sequence numbers of the embodiments disclosed above are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0145] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. An offshore construction platform, characterized in that, include: The platform body, multiple pile legs arranged circumferentially along the platform body, and suction pile foundations corresponding to each pile leg; the suction pile foundation includes a suction pile cylinder; One end of the pile leg is connected to the platform body to provide support for the platform body; The other end of the pile leg is connected to the top of the corresponding suction pile cylinder, which is used to penetrate the seabed of the construction area and fix the main body of the platform.

2. The offshore construction platform as described in claim 1, characterized in that, Also includes: A lifting system is installed for each pile leg; The lifting system includes a transmission device and a locking device. The transmission device includes a drive unit, a gear, and a rack disposed inside the platform body. The locking device includes a pin disposed inside the platform body and a hole disposed in the pile leg. The lifting system is used to drive the gear to rotate in the corresponding adjustment direction through the drive device when the height of the platform body needs to be adjusted, and to drive the pile leg to move through the rack, so that the platform body moves in the target direction until it stops moving at the target position, and inserts the pin into the socket on the pile leg corresponding to the position of the pin.

3. The offshore construction platform as described in claim 1, characterized in that, Also includes: Suction pump; The suction pump is connected to the top of the suction pile cylinder and is used to extract water from the suction pile cylinder during the process of driving the suction pile cylinder into the seabed. And injecting water into the suction pile cylinder during the process of pulling the suction pile cylinder out of the seabed; and / or The top of the suction pile cylinder is provided with a manhole and a drainage hole, the drainage hole being used to discharge water pumped out by the suction pump; and / or The construction platform also includes a ballast system installed inside the main body of the platform.

4. The offshore construction platform as described in claim 1, characterized in that, Also includes: Piling system; The pile driving system includes: a pile driving water pump, a pile driving nozzle, a pile driving pipeline, and a surfactant storage tank; The pile driving nozzle is located at the top of the suction pile cylinder and the bottom of the pile leg; one end of the pile driving pipeline is connected to the pile driving water pump, and the other end is connected to the pile driving nozzle; the surfactant storage tank is connected to the pile driving water pump; the pile driving water pump is used to draw in seawater, mix the seawater with the surfactant to form a pile driving fluid, and pressurize and pump the pile driving fluid into the pile driving pipeline.

5. The offshore construction platform as described in claim 1, characterized in that, The main body of the platform also includes: functional modules and supporting modules, and a deck; The functional module and supporting module are fixedly connected to the upper surface of the deck; The functional modules and supporting modules include at least one of the following: directional drilling rig module, directional drilling control module, power module, drill rod stacking area, office module, mud material storage area, and construction platform crane.

6. A design method for an offshore construction platform based on any one of claims 1-5, characterized in that, include: Obtain the design basis; the design basis includes engineering geology, hydrological data, operational capabilities, and operational environment requirements. Based on the requirements of the operating capacity and operating environment, the weight and dimensions of each piece of equipment are determined; Obtain the equipment parameters of each device, and based on the equipment parameters, determine the overall layout of the platform and perform weight and center of gravity analysis; Based on the overall layout, the main structure design and compartment division of the platform are determined; Based on the marine environment conditions of the platform operation area, the main platform structure and the weight of each piece of equipment, the pile leg structure was determined. The structure of the lifting system is determined based on the main dimensions of the platform, the leg structure, and the total weight of each piece of equipment. Determine the structural strength of the platform body under towing operations, operational conditions, and storm self-sustaining conditions, and output the load and bending moment at the foundation. Based on the platform's main structure, pile leg structure, and in-situ analysis output data, the suction pile foundation structure and the percussion pile system structure are determined. Based on the design of the main structure of the platform, the division of the compartments, the leg structure, the structure of the lifting system, the suction pile foundation structure and the pile driving system structure, the design scheme of the target offshore construction platform is obtained.

7. The design method for an offshore construction platform as described in claim 6, characterized in that, The determination of the weight and dimensions of each piece of equipment based on the requirements of the operational capabilities and working environment includes: Based on the requirements of the operational capabilities and the operational environment, the equipment operational capability parameters are determined; wherein, the operational capabilities include: the target operational pipeline length and the target operational pipeline diameter; the operational environment includes: the operational sea area depth and the operational sea area geological parameters; Based on the equipment's working capacity parameters, the weight and dimensions of the construction equipment are obtained; wherein, the construction equipment includes: a drilling rig module; the auxiliary equipment includes at least one of the following: a directional drilling control module, a power module, a drill rod stacking area, and an office module; The weight and dimensions of the auxiliary equipment are obtained based on the weight and dimensions of the construction equipment.

8. The design method for an offshore construction platform as described in claim 6, characterized in that, The determination of the pile leg structure based on the marine environmental conditions of the platform operation area, the main platform structure, and the weight of each piece of equipment includes: The length of the pile leg is determined based on the marine environmental conditions of the platform's operating area; Based on the main platform structure and the weight of each piece of equipment, the number and location of the pile legs are determined; Based on the length, number, location, and maximum load of the pile legs, the cross-sectional dimensions of the pile legs are obtained; wherein, the maximum load includes the maximum weight of the platform body and the total weight of all equipment.

9. A construction method for an offshore construction platform based on any one of claims 1-5, characterized in that, Includes the following steps: After receiving the penetration command, the suction pile system starts the suction pump to extract the seawater inside the suction pile cylinder; under the action of negative pressure, the suction pile cylinder penetrates into the seabed; after the suction pile cylinder reaches the preset penetration depth, the lifting system raises the main body of the platform, so that its air gap height reaches the preset height, and the locking device locks it; the suction pile penetration operation is completed. After receiving the pile extraction command, the pile flushing system starts the pile flushing water pump and uses flushing fluid to strip away the mud and sand near the pile shoe of the suction pile, expanding the upward channel of the suction pile. After receiving the penetration command, the lifting system unlocks the locking device and lowers the main body of the platform to the sea surface to provide buoyancy. After receiving the penetration command, the suction pile system starts the suction pump, injects water into the suction pile, and then the lifting system raises the pile legs to pull the suction pile from the seabed, thus completing the suction pile extraction operation.

10. The construction method for the offshore construction platform as described in claim 9, characterized in that, Also includes: During the suction pile driving operation, at least one of the following adjustments are made to control the tilt angle of the construction platform: the driving sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump. During the extraction of the suction pile, at least one of the following adjustments is made to control the tilt angle of the construction platform: the extraction sequence of the suction pile cylinder, the working power of the lifting device corresponding to different suction pile cylinders, and the working power of the suction pump.

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