Totally self-contained subsea oil and gas processing system

Abstract

The present application relates to a kind of self-sufficient underwater oil and gas processing system.Compared with prior art, the expander module of the present application utilizes the fluid pressure difference of mixed gas fluid to convert pressure energy into mechanical energy, while further separating the mixed gas fluid, the generator module converts mechanical energy into electrical energy, the secondary separation module separates the further separated mixed gas fluid to obtain natural gas, residual oil and residual water, the oil and gas transfer module combines and transports the oil of pre-separation module and the residual oil of the secondary separation module, and the oil and gas transfer module transports natural gas.The underwater oil and gas processing system is deployed on the seabed as a whole, eliminating the dependence on surface platform and floating production unit, and is modularly designed to adapt to deepwater engineering installation and operation and maintenance, reduce construction investment and operation and maintenance cost, realize energy closed-loop self-sufficiency, adapt to extreme environment, can adapt to long-distance, less intervention deep-sea development scene, and at the same time improve the separation and purification of natural gas and oil.

Description

Technical Field

[0001] This invention relates to the field of marine resource development technology, and in particular to a fully self-sustaining underwater oil and gas processing system. Background Technology

[0002] The continued rise in global energy demand has made deepwater and ultra-deepwater oil and gas fields the core growth point for oil and gas development, but their efficient development is still constrained by multiple key technological bottlenecks.

[0003] Traditional development models rely heavily on floating production facilities (FPSOs) or surface platforms. In extreme environments with water depths exceeding 500 meters, they are susceptible to severe sea conditions, which can lead to a surge in the risk of production stoppages. Furthermore, they involve large initial construction investments, high long-term operation and maintenance costs, and reliance on shore-based power supply or fuel replenishment, making them difficult to adapt to long-distance, low-human-intervention deep-sea development scenarios. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fully self-sustaining underwater oil and gas processing system.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] According to the present invention, a fully self-sustaining underwater oil and gas processing system includes a pre-separation module, an expander module, a generator module, a secondary separation module, and an oil and gas transportation module.

[0007] The feed pipeline of the pre-separation module is used to receive raw gas, and the pre-separation module separates the raw gas to obtain oil, water and mixed gas fluid.

[0008] The pre-separation module's mixed gas fluid discharge pipeline is connected to the expander module's inlet pipeline. The expander module is used to convert pressure energy into mechanical energy using the fluid pressure difference of the mixed gas and to further separate the mixed gas fluid.

[0009] The expander module is coaxially connected to the generator module, which is used to convert mechanical energy into electrical energy; the discharge pipe of the expander module is connected to the inlet pipe of the secondary separation module, which is used to further separate the mixed gas fluid to obtain natural gas, residual oil and residual water;

[0010] The oil discharge pipeline of the pre-separation module and the residual oil discharge pipeline of the secondary separation module are connected to the oil delivery pipeline of the oil and gas delivery module, so that the oil and gas delivery module can combine and deliver the oil from the pre-separation module and the residual oil from the secondary separation module; the natural gas discharge pipeline of the secondary separation module is connected to the natural gas delivery pipeline of the oil and gas delivery module, so that the oil and gas delivery module can deliver natural gas.

[0011] Compared with existing technologies, the pre-separation module of this invention receives raw gas and separates it to obtain oil, water, and a mixed gas fluid. The expander module uses the pressure difference of the mixed gas fluid to convert pressure energy into mechanical energy and further separates the mixed gas fluid. The generator module converts mechanical energy into electrical energy. The secondary separation module separates the further separated mixed gas fluid to obtain natural gas, residual oil, and residual water. The oil and gas transportation module combines and transports the oil from the pre-separation module and the residual oil from the secondary separation module. The oil and gas transportation module also transports the natural gas. This subsea oil and gas processing system is deployed on the seabed, eliminating dependence on surface platforms and floating production units. Its modular design is adaptable to deep-water engineering installation and operation and maintenance, reducing construction investment and operation and maintenance costs. It achieves energy self-sufficiency and adapts to extreme environments. It can be adapted to long-distance, low-intervention deep-sea development scenarios, achieving fully self-sustaining subsea oil and gas processing and long-distance transmission. It is suitable for deep-water and ultra-deep-water oil and gas field development with water depths greater than 500m, and simultaneously improves the separation and purification of natural gas and oil.

[0012] Preferably, the pre-separation module is connected to the expander module via a dehydration module and a carbon dioxide removal module;

[0013] The pre-separation module's mixed gas fluid discharge pipeline is connected to the inlet pipeline of the dehydration module, which is used to remove moisture from the mixed gas fluid.

[0014] The discharge pipe of the dehydration module is connected to the inlet pipe of the carbon dioxide removal module, which is used to remove carbon dioxide from the dehydrated mixed gas fluid.

[0015] The mixed gas fluid discharge pipeline of the carbon dioxide removal module is connected to the expander module so that the expander module can utilize the fluid pressure difference of the mixed gas flow for dehydration and decarbonization.

[0016] Compared with the prior art, this application uses a dehydration module to remove moisture from the mixed gas fluid, a carbon dioxide removal module to remove carbon dioxide from the dehydrated mixed gas fluid, and an expander module to utilize the fluid pressure difference of the dehydrated and decarbonized mixed gas fluid, which can prevent corrosion of the expander module and the power generation module, and the fluid pressure difference is more stable.

[0017] Preferably, the subsea oil and gas processing system further includes a carbon dioxide reinjection module, which includes a carbon dioxide reinjection booster pump and a compressor; the carbon dioxide discharge pipeline of the carbon dioxide removal module is connected to the inlet pipeline of the compressor, the carbon dioxide removal module dries the carbon dioxide, the compressor is used to pressurize the dried carbon dioxide, and the discharge pipeline of the compressor is connected to the carbon dioxide reinjection booster pump; the carbon dioxide reinjection booster pump is used to pressurize the pressurized carbon dioxide for formation sealing.

[0018] Preferably, the underwater oil and gas processing system further includes an underwater control subsystem, which includes sensors, a data processing module, a decision-making module, an energy management module, a control module, and actuators.

[0019] The sensor collects operational data from the underwater oil and gas processing system.

[0020] The sensor module is connected to the data processing module, which is used to process the operating data;

[0021] The data processing module is connected to the decision module, which is used to analyze the processed data and generate decision instructions.

[0022] The decision-making module is connected to the energy management module, and the energy management module dynamically adjusts the energy allocation of the corresponding module according to the decision instructions;

[0023] The decision module is connected to the control module, and the control module is connected to the actuator. The control module controls the actuator to adjust the corresponding module according to the decision instructions.

[0024] Preferably, the sensor is also connected to the control module and the energy management module. When the sensor collects abnormal data, it sends a trigger signal to the control module and the energy management module. The control module controls the actuator to adjust the abnormal module, and the energy management module allocates emergency energy to the abnormal module.

[0025] And / or, the underwater oil and gas processing system also includes an intelligent flow protection module and a chemical injection module. The underwater control subsystem autonomously adjusts the heating unit temperature of the intelligent flow protection module and the chemical injection amount of the chemical injection module based on hydrate generation data.

[0026] Preferably, the underwater oil and gas processing system further includes an energy storage module, which is electrically connected to the generator module. The energy storage module provides initial power to the underwater oil and gas processing system and stores excess electrical energy generated by the generator module.

[0027] Preferably, the underwater oil and gas processing system further includes an underwater foundation support module, which adopts a suction caisson structure. The suction caisson structure is fixed to the seabed by adjusting negative pressure. The outer wall of the caisson of the underwater foundation support module is provided with a nickel-based alloy sacrificial anode anti-corrosion layer. The underwater foundation support module is used to support the pre-separation module, the expander module, the generator module, the secondary separation module, and the oil and gas transportation module.

[0028] Preferably, the subsea oil and gas processing system further includes a produced water treatment module and a water reinjection module; the water discharge pipeline of the pre-separation module is connected to the inlet pipeline of the produced water treatment module, and the produced water treatment module processes the water;

[0029] The water reinjection module includes a water reinjection booster pump and a filtration device; the discharge pipeline of the produced water treatment module and the residual water discharge pipeline of the secondary separation module are connected to the inlet pipeline of the filtration device; the filtration device combines and filters the treated water from the produced water treatment module and the residual water from the secondary separation module.

[0030] The discharge pipeline of the filtration device is connected to a water reinjection booster pump, which is used to pressurize the filtered water for formation sealing.

[0031] Preferably, the pre-separation module and the secondary separation module are connected to the oil and gas transmission module via a pressurization module, and the oil and gas transmission module includes an oil transmission module and a natural gas transmission module;

[0032] The booster module includes a natural gas booster module and an oil booster module; the oil discharge pipe of the pre-separation module and the residual oil discharge pipe of the secondary separation module are connected to the inlet pipe of the oil booster module; the oil booster module uses an underwater positive displacement pump to boost the combined oil; the discharge pipe of the oil booster module is connected to the delivery pipe of the oil delivery module.

[0033] The natural gas discharge pipeline of the secondary separation module is connected to the inlet pipeline of the natural gas booster module. The natural gas booster module uses a pressure-resistant sealed housing with an internal underwater screw compressor. The underwater screw compressor boosts the natural gas. The discharge pipeline of the natural gas booster module is connected to the delivery pipeline of the natural gas delivery module.

[0034] Preferably, the pre-separation module includes a cyclone separator, a tubular separator, and a gravity cyclone composite multiphase separator;

[0035] The raw material gas is a mixture of sand, oil, gas and water;

[0036] The feed pipe of the cyclone separator is used to receive raw material gas. The pressure chamber of the cyclone separator has built-in spiral guide vanes so that the cyclone separator can use centrifugal force to separate sand particles in the raw material gas.

[0037] The discharge pipe of the cyclone desander is connected to the inlet pipe of the tubular separator, and the tubular separator performs preliminary gas-liquid separation on the raw gas after desandering.

[0038] The discharge pipe of the tubular separation device is connected to a gravity cyclone composite multiphase separator. The multiphase separator chamber of the gravity cyclone composite multiphase separator is divided into an upper gas phase zone, a middle liquid phase zone, and a lower water phase zone. The multiphase separator chamber has a built-in cyclone separation core so that the gravity cyclone composite multiphase separator can separate the raw gas from the initial gas-liquid separation, separating the mixed gas fluid to the upper gas phase zone, separating the oil to the middle liquid phase zone, and separating the water to the lower water phase zone. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the fully self-sustaining underwater oil and gas processing system according to an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of the intelligent AI decision-making and control logic in a fully self-sustaining underwater oil and gas processing system according to an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of the specific structure of the fully self-sustaining underwater oil and gas processing system according to an embodiment of the present invention.

[0042] Reference numerals: 1. Pre-separation module; 101. Cyclone desander; 102. Tubular separator; 103. Gravity cyclone composite multiphase separator; 2. Dewatering module; 3. Carbon dioxide removal module; 4. Expander module; 5. Generator module; 6. Energy storage module; 7. Secondary separation module; 701. Axial flow cyclone separator; 8. Booster module; 801. Subsea screw compressor; 802. Subsea positive displacement pump; 9. Produced water treatment module; 10. Carbon dioxide reinjection module; 11. Oil and gas transportation module; 12. Water reinjection module; 13. Subsea support facility subsystem; 14. Subsea control subsystem. Detailed Implementation

[0043] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0044] Through in-depth research and improvement exploration of underwater oil and gas processing systems, the applicant discovered that: in restricted sea areas such as military restricted zones, shipping lanes, and ecological red zones, the deployment of surface facilities limits the economic development of a large amount of high-quality oil and gas resources; although countries such as Norway and Brazil have carried out demonstration applications of single modules such as seabed compression and separation, verifying the potential of underwater processing technology in enhancing recovery rates and reducing energy consumption, existing systems have not yet achieved "fully self-sufficient" underwater deployment. There are technological gaps in core areas such as closed-loop energy supply, adaptability to extreme environments, and intelligent operation and maintenance. Moreover, they generally suffer from insufficient energy self-sufficiency, reliance on shore-based power supply or fuel replenishment, and a lack of mature autonomous decision-making and intelligent operation and maintenance mechanisms, making them unsuitable for long-distance, low-intervention deep-sea development scenarios; at the same time, there is still a gap with traditional deep-sea powers in the industrial application of key technologies such as seabed processing and equipment reliability under extreme conditions. The demand for energy companies to expand into deep-sea and overseas markets is becoming increasingly urgent, and there is an urgent need for independently controllable, fully self-sufficient underwater oil and gas processing technology to break through the bottleneck of energy security.

[0045] Based on this, the technical solutions provided by the various embodiments of this application will be described below with reference to the accompanying drawings.

[0046] This specification presents an embodiment of a fully self-sustaining underwater oil and gas processing system, such as... Figure 1 , Figure 2 as well as Figure 3 As shown, it includes a pre-separation module 1, an expander module 4, a generator module 5, a secondary separation module 7, and an oil and gas transmission module 11.

[0047] The feed line of the pre-separation module 1 is used to receive the raw gas, and the pre-separation module 1 separates the raw gas to obtain oil, water, and a mixed gas fluid. The mixed gas fluid discharge line of the pre-separation module 1 is connected to the inlet line of the expander module 4. The expander module 4 is used to convert pressure energy into mechanical energy using the fluid pressure difference of the mixed gas and to further separate the mixed gas fluid.

[0048] Expander module 4 is coaxially connected to generator module 5, which is used to convert mechanical energy into electrical energy; the discharge pipe of expander module 4 is connected to the inlet pipe of secondary separation module 7, which is used to further separate the mixed gas fluid to obtain natural gas, residual oil and residual water.

[0049] The secondary separation module 7 is the core device for the fine separation of the gas-liquid two-phase fluid discharged from the expander module 4. Its function is to efficiently separate residual oil and residual water entrained in the preceding processes (pre-separation, expander pressure energy conversion) to improve the purity of each phase of oil, gas, and water, while ensuring the stable operation of subsequent power generation, transmission, and reinjection processes. It primarily employs an axial-flow cyclone separator 701, with a shell made of deep-sea pressure-resistant alloy steel, capable of withstanding high hydrostatic pressure in ultra-deep water (>500m). Internally, it features multi-stage cyclone blades and a collection structure. The gas-liquid two-phase fluid (methane-rich gas + trace oil / water droplets) discharged from the expander module 4 enters the separator, forming a high-speed rotating flow field under the action of the cyclone blades. The denser oil and water droplets are thrown towards the cylinder wall under centrifugal force and settle along the wall to the bottom liquid phase collection area; the less dense methane-rich gas converges towards the center and is discharged through the top gas phase outlet, achieving efficient gas-liquid separation.

[0050] The oil discharge pipeline of the pre-separation module 1 and the residual oil discharge pipeline of the secondary separation module 7 are connected to the oil delivery pipeline of the oil and gas delivery module 11, so that the oil and gas delivery module 11 can combine and deliver the oil from the pre-separation module 1 and the residual oil from the secondary separation module 7; the natural gas discharge pipeline of the secondary separation module 7 is connected to the natural gas delivery pipeline of the oil and gas delivery module 11, so that the oil and gas delivery module 11 can deliver natural gas.

[0051] The secondary separation module 7 is located after the dehydration module 2, the carbon dioxide removal module 3, the produced water treatment module 9, and the underwater differential pressure generator system. The secondary separation module 7 is a device for fine separation of gas and liquid phases. The secondary separation module 7 is used to further separate the residual liquid or gas entrained in the previous process to improve the separation purity of oil, gas and water phases and the overall processing efficiency of the system.

[0052] The expander module 4 of the underwater differential pressure generator system is an underwater expander suitable for multiphase flow conditions. It is installed between the high-pressure fluid pipeline and the low-pressure treatment pipeline. Its inlet is connected to the high-pressure fluid pipeline, and its outlet is connected to the low-pressure treatment pipeline. It utilizes the fluid pressure difference formed between the high and low pressures of the oil and gas fluid to convert fluid pressure energy into mechanical energy. The high-pressure fluid pipeline forms a high-pressure network, and the low-pressure treatment pipeline forms a low-pressure network.

[0053] Generator module 5 is an underwater generator suitable for deep-sea operations. It is coaxially connected to expander module 4 and converts mechanical energy into electrical energy under the drive of expander module 4. Generator module 5 supplies power to various modules of the underwater oil and gas processing system.

[0054] This invention is the first to integrate the expander and generator module 5 into a single unit, and proposes a novel concept for the coupled application of underwater differential pressure power generation and oil and gas processing, taking into account the full-process requirements of underwater oil and gas treatment. Based on existing mature expander and generator structures, through system-level architecture design, functional coordination, and operating condition adaptation, it innovatively integrates them into a fully self-sustaining underwater oil and gas treatment system. This allows such equipment to break through traditional application scenario limitations and adapt to the fully self-sustaining operation requirements of deep-sea environments without surface facilities. Its core value lies in the innovation of application concepts and system integration.

[0055] In one embodiment, the pre-separation module 1 is connected to the expander module 4 via the dehydration module 2 and the carbon dioxide removal module 3.

[0056] The pre-separation module 1's mixed gas fluid discharge line is connected to the inlet line of the dehydration module 2, which removes moisture from the mixed gas fluid. The dehydration module 2's discharge line is connected to the inlet line of the carbon dioxide removal module 3, which removes carbon dioxide from the dehydrated mixed gas fluid. The carbon dioxide removal module 3's mixed gas fluid discharge line is connected to the expander module 4, so that the expander module 4 utilizes the fluid pressure difference of the dehydrated and decarbonized mixed gas flow.

[0057] Dehydration module 2 is located on the gas phase outlet pipeline of pre-separation module 1. Dehydration module 2 includes a gas dehydration device, which is a physical dehydration device and / or an adsorption dehydration device suitable for underwater operation. Dehydration module 2 is used to dehydrate the natural gas after preliminary separation to reduce the moisture content in the gas, prevent hydrate formation, and meet the requirements of subsequent processing, pressurization, or transportation. Carbon dioxide removal module 3 is located after dehydration module 2. Carbon dioxide removal module 3 includes a carbon dioxide removal device, which is a physical adsorption removal device and / or a membrane separation removal device. It is used to remove carbon dioxide from the dehydrated natural gas to form methane-rich gas and carbon dioxide-rich gas.

[0058] In one embodiment, the subsea oil and gas processing system further includes a carbon dioxide reinjection module 10, which includes a carbon dioxide reinjection booster pump and a compressor; the carbon dioxide discharge pipeline of the carbon dioxide removal module 3 is connected to the inlet pipeline of the compressor, the carbon dioxide removal module 3 dries the carbon dioxide, the compressor is used to pressurize the dried carbon dioxide, and the discharge pipeline of the compressor is connected to the carbon dioxide reinjection booster pump; the carbon dioxide reinjection booster pump is used to pressurize the pressurized carbon dioxide for formation sealing.

[0059] The carbon dioxide removal module 3 is used to remove carbon dioxide from the dehydrated natural gas to obtain methane-rich gas and carbon dioxide-rich gas. The methane-rich gas enters the differential pressure generator system, and the carbon dioxide-rich gas is pressurized and then enters the carbon dioxide reinjection module 10.

[0060] In one embodiment, the underwater oil and gas processing system further includes an underwater control subsystem 14, which includes sensors, a data processing module, a decision-making module, an energy management module, a control module, and actuators.

[0061] Sensors collect operational data from the underwater oil and gas processing system. The sensor module connects to a data processing module, which processes the operational data. The data processing module then connects to a decision-making module, which analyzes the processed data and generates decision commands. The decision-making module connects to an energy management module, which dynamically adjusts the energy allocation of the corresponding modules based on the decision commands. Finally, the decision-making module connects to a control module, which in turn connects to actuators. The control module then controls the actuators to adjust the corresponding modules based on the decision commands.

[0062] The underwater AI control subsystem adopts an all-electric architecture design, with its core components including an underwater valve actuator, a control module, a data processing module, and an AI decision-making module. These components work together to achieve intelligent system control. The data processing module is responsible for collecting and processing various operational data. The AI ​​decision-making module generates decision commands based on a preset intelligent algorithm model. The control module generates corresponding execution commands based on these decision commands, and the control module's commands are transmitted to the actuator. The AI ​​decision-making module calls the preset intelligent algorithm model to analyze the valid data, combines it with the system's preset control logic to generate corresponding decision commands, and simultaneously distributes these commands to the energy management module and the control module. The actuator is electrically driven and receives command signals from the control module and the energy management module to complete device start / stop and valve opening adjustment actions, thereby controlling the fluid transport path. The underwater valve actuator is electrically driven and is used to perform start / stop and valve opening adjustment actions.

[0063] In one embodiment, the sensor is also connected to a control module and an energy management module. When the sensor collects abnormal data, it sends a trigger signal to the control module and the energy management module. The control module controls the actuator to adjust the abnormal module, and the energy management module allocates emergency energy to the abnormal module.

[0064] And / or, the underwater oil and gas processing system also includes an intelligent flow protection module and a chemical injection module. The underwater control subsystem 14 autonomously adjusts the heating unit temperature of the intelligent flow protection module and the chemical injection amount of the chemical injection module based on the hydrate generation data.

[0065] The underwater support facility subsystem 13 provides fundamental support for the underwater treatment system. Its core components include an intelligent flow support module, a chemical injection module, and an underwater foundation support structure. During operation, the underwater AI control system's real-time monitoring unit collects data related to hydrate formation. The AI ​​control module then generates control commands based on this data. Through coordinated adjustments, the control module regulates the heating temperature of the flow support module's heating unit and the injection volume of the chemical injection module, effectively reducing the amount of chemicals such as ethylene glycol or methanol used while ensuring system safety.

[0066] In one embodiment, the underwater oil and gas processing system further includes an energy storage module 6, which is electrically connected to the generator module 5. The energy storage module 6 provides initial power to the underwater oil and gas processing system and stores excess electrical energy generated by the generator module 5.

[0067] The underwater differential pressure power generation system includes: an underwater expander module 4, a generator module 5, an energy storage module 6, and an energy management module. The energy storage module 6 includes a rechargeable battery and / or a supercapacitor, electrically connected to the generator module 5, and is used to provide initial power during system startup and to store excess energy generated by the generator module 5 during production. The energy management module dynamically adjusts the power output of the generator module 5 and the charging / discharging strategy of the energy storage module 6 according to system load changes. The energy management module of the underwater differential pressure power generation system is electrically connected to the generator module 5, the energy storage module 6, and each electrical load, and has rectification and voltage regulation output functions. During system startup, it prioritizes power supply to the underwater AI control subsystem and key actuators.

[0068] In traditional oil and gas development models, expander module 4 and generator module 5 are highly dependent on surface platforms and floating production facilities (FPSOs) for support, require shore-based power and fuel replenishment, and are heavily influenced by local weather conditions (such as typhoons). This new approach completely eliminates the traditional reliance on surface platforms and FPSOs, deploying all modules on the seabed, enabling fully subsea oil and gas development without surface infrastructure support. It is suitable not only for deep-water / ultra-deep-water oil and gas fields but also for developing high-quality oil and gas resources in military restricted areas, along shipping lanes, and in ecological red zones where surface infrastructure deployment is limited, thus solving the blind spots in development scenarios encountered by traditional solutions.

[0069] Traditional underwater equipment relies entirely on power supply from surface platforms / shore bases. To achieve full underwater deployment, it is necessary to solve the closed-loop problem that "the unit is both a process link and the core of the system's energy." It is also necessary to cover energy supply under all operating conditions, including startup, fluctuations, and emergencies, and completely get rid of energy dependence on surface facilities. This is the core bottleneck to full self-sufficiency.

[0070] The integrated generation-storage-distribution energy closed-loop self-sufficiency system of the present invention: the generator module 5, the energy storage module 6, and the energy management module of the underwater control subsystem 14 work in deep collaboration. The unit uses the electrical energy generated by the pressure difference of oil and gas fluids to directly supply power to all electrical modules in the entire system, and the excess electrical energy is stored in the energy storage module 6. During the system startup phase, the energy storage module 6 provides the initial power supply. Under fluctuating operating conditions, the energy management module dynamically adjusts the energy distribution. Under abnormal operating conditions, emergency energy supply can be directly triggered, completely eliminating the dependence on power supply from the sea surface platform / shore base and achieving complete energy self-sufficiency.

[0071] The all-electric intelligent autonomous control architecture features multi-dimensional sensors built into the unit to collect operational data in real time. This data is then integrated with an underwater AI control subsystem, enabling autonomous adjustment of operating parameters, early warning of faults, and emergency self-handling of abnormal conditions. It can complete most operational and maintenance tasks throughout its entire lifecycle without human intervention, making it suitable for deep-sea development scenarios requiring minimal human intervention. Simultaneously, pre-installed dehydration and decarbonization modules pre-treat the media entering the expander, preventing corrosion and hydrate blockage from the source.

[0072] In one embodiment, the underwater oil and gas processing system further includes an underwater foundation support module. The underwater foundation support module adopts a suction caisson structure, which is fixed to the seabed by adjusting the negative pressure. The outer wall of the caisson of the underwater foundation support module is provided with a nickel-based alloy sacrificial anode anti-corrosion layer. The underwater foundation support module is used to support the pre-separation module 1, the expander module 4, the generator module 5, the secondary separation module 7, and the oil and gas transportation module 11.

[0073] The underwater support facility subsystem 13 includes an underwater foundation support structure. The underwater foundation support module adopts a suction caisson structure. The suction caisson is sunk into the seabed soil by adjusting the negative pressure inside the caisson cylinder. Stable bonding with the seabed soil is achieved by adjusting the negative pressure inside the caisson cylinder, completing the installation and fixing of the various modules of the underwater oil and gas processing system. The outer wall of the suction caisson is equipped with a nickel-based alloy sacrificial anode anti-corrosion layer, which can significantly improve the structure's corrosion resistance in complex underwater environments and extend its service life.

[0074] In ultra-deep waters with depths greater than 500m, there are extreme environmental characteristics such as high hydrostatic pressure, low temperature, and strong corrosion. Conventional land-based / sea-based expanders and generators, lacking dedicated pressure-resistant and corrosion-resistant designs, are prone to problems such as shell rupture and component corrosion failure when directly deployed underwater. At the same time, the low-temperature environment can easily cause fluid hydrate formation, resulting in blockage of the expander's flow channels and seriously compromising the stability of equipment operation.

[0075] To address the three core challenges faced by core power units in ultra-deep water environments—namely, stability, construction adaptability, and corrosion resistance and durability—this invention employs a design scheme that coordinates the deployment of suction-type caisson foundation support modules with an integrated expander-generator unit. All designs are tailored to the unit's operational characteristics, and the core technological advantages are as follows:

[0076] 1. Pile-free construction, adaptable to ultra-deepwater modular installation, reducing the difficulty of unit deployment. The expander-generator unit is the core of the system's energy self-sufficiency and needs to be installed underwater in a modular fashion simultaneously with the pre-separation module and secondary separation module. Traditional pile foundation construction is limited by the space and equipment available in ultra-deepwater operations and cannot match the modular installation process, significantly extending the construction cycle and increasing development costs. The suction caisson adopts a negative pressure self-sinking installation method, eliminating the need for large pile driving equipment. It can be pre-integrated on land and then deployed as a whole to the target seabed. Fixing can be completed by remotely adjusting the negative pressure, perfectly adapting to the modular design concept of the system. This enables the synchronous installation and commissioning of the unit with other modules, significantly reducing the deployment difficulty and construction cost of the core power unit in ultra-deepwater environments.

[0077] 2. The suction caisson forms an integrated embedded structure with the seabed soil through negative pressure. The friction and confining pressure formed between the side wall of the caisson and the seabed soil can effectively resist the external forces brought by strong ocean currents and seabed geological disturbances, providing ultra-high voltage fixed stability for the unit. This ensures that the unit maintains a precise installation position and levelness during long-term operation, and guarantees the accuracy of the coaxial direct drive structure from the basic support level, avoiding power generation efficiency loss and equipment failure caused by equipment displacement.

[0078] 3. A nickel-based alloy sacrificial anode anti-corrosion layer provides overall corrosion protection for the foundation support and the unit, extending the unit's underwater service life. In ultra-deep-water, high-salt, and highly corrosive marine environments, corrosion failure of the equipment's foundation support structure can lead to unit tilting and loosening, indirectly affecting unit operation. Simultaneously, corrosion products from the support structure adhere to the unit's surface with seawater flow, accelerating localized corrosion. This invention incorporates a nickel-based alloy sacrificial anode anti-corrosion layer on the outer wall of the suction caisson. Nickel-based alloys possess excellent corrosion resistance in ultra-deep-water, highly corrosive environments. The sacrificial anode design, through electrochemical protection principles, not only protects the caisson itself from corrosion but also creates a localized anti-corrosion electric field, providing auxiliary anti-corrosion protection for the unit deployed on the caisson, achieving overall corrosion protection for the foundation support module and the core power unit. This significantly extends the underwater service life, making it suitable for deep-sea, long-distance, and minimally manned development scenarios.

[0079] The suction caisson structure, by optimizing the friction coefficient of the cylinder wall and the caisson's insertion depth, can be adapted to various deep-sea bed geologies such as soft clay, sand, silt, and gravel. This solves the problem of poor adaptability of traditional solutions to seabed geology, meets the development needs of different deep-water oil and gas fields, and greatly improves the versatility and practicality of the solution.

[0080] In one embodiment, the underwater oil and gas processing system further includes a produced water treatment module 9 and a water reinjection module 12; the water discharge pipeline of the pre-separation module 1 is connected to the inlet pipeline of the produced water treatment module 9, and the produced water treatment module 9 processes the water.

[0081] The water reinjection module 12 includes a water reinjection booster pump and a filter device; the discharge pipeline of the produced water treatment module 9 and the residual water discharge pipeline of the secondary separation module 7 are connected to the inlet pipeline of the filter device; the filter device combines and filters the treated water of the produced water treatment module 9 and the residual water of the secondary separation module 7.

[0082] The discharge pipeline of the filter device is connected to a water reinjection booster pump, which is used to pressurize the filtered water for formation sealing.

[0083] The produced water treatment module 9 is installed on the water phase outlet pipeline of the pre-separation module 1. The produced water treatment module 9 includes at least one water treatment device, which includes a filtration device and an oil-water separation device. The produced water treatment module 9 is used to treat the separated produced water so that its water quality meets the reinjection requirements. The treated produced water enters the water reinjection module 12 for reinjection treatment.

[0084] The water reinjection module 12 of the subsea reinjection subsystem includes a reinjection booster pump, a filter device, and a flow meter. The reinjection booster pump is a corrosion-resistant centrifugal pump, and the filter device is a high-precision filter screen. The inlet of the water reinjection module 12 is connected to the produced water branch of the media diversion unit, and the outlet is connected to the reinjection well through the reinjection pipeline. It is used to filter and pressurize the qualified produced water and then inject it into the formation. The water reinjection module 12 is used to first perform secondary filtration on the qualified produced water, and then increase the pressure of the produced water through the reinjection booster pump, and finally inject the produced water into the formation to realize the recycling of water resources and avoid environmental pollution caused by marine discharge.

[0085] The carbon dioxide reinjection module 10 of the reinjection subsystem includes core equipment such as a reinjection booster pump and a compressor. The inlet of the carbon dioxide reinjection module 10 is connected to the carbon dioxide branch line, and the outlet is connected to the reinjection well via a carbon dioxide reinjection pipeline. It is used to inject purified carbon dioxide into the formation after drying and pressurization. The carbon dioxide reinjection module 10 is used to dry the separated and purified carbon dioxide, and then inject it into the formation through the compressor to achieve storage. Simultaneously, it can help improve oil and gas recovery rates, meeting the requirements of low-carbon and environmentally friendly development.

[0086] The reinjection subsystem is used to achieve compliant disposal and resource reuse of byproducts from underwater oil and gas processing. The reinjection subsystem includes a water reinjection module 12 and a carbon dioxide reinjection module 10.

[0087] In one embodiment, the pre-separation module 1 and the secondary separation module 7 are connected to the oil and gas transmission module 11 via the pressurization module 8. The oil and gas transmission module 11 includes an oil transmission module and a natural gas transmission module.

[0088] The booster module 8 includes a natural gas booster module 8 and an oil booster module 8; the oil discharge pipe of the pre-separation module 1 and the residual oil discharge pipe of the secondary separation module 7 are connected to the inlet pipe of the oil booster module 8. The oil booster module 8 adopts an underwater positive displacement pump to boost the combined oil; the discharge pipe of the oil booster module 8 is connected to the delivery pipe of the oil delivery module.

[0089] The natural gas discharge pipeline of the secondary separation module 7 is connected to the inlet pipeline of the natural gas booster module 8. The natural gas booster module 8 uses a pressure-resistant sealed shell to build an underwater screw compressor 801. The underwater screw compressor 801 boosts the natural gas. The discharge pipeline of the natural gas booster module 8 is connected to the delivery pipeline of the natural gas delivery module.

[0090] The oil and gas transmission subsystem is connected to the output end of the oil and gas processing subsystem and adopts a deep-water adapted transmission structure. The oil and gas transmission subsystem includes a booster module 8, which is equipped with special booster equipment for the different medium characteristics of natural gas and crude oil to ensure that the requirements for long-distance external transmission are met.

[0091] The booster module 8 of the oil and gas transmission subsystem includes a natural gas booster module 8 and a crude oil booster module 8.

[0092] The natural gas booster module 8 is a submersible screw compressor 801, employing a high-pressure resistant sealed housing. The inlet of the natural gas booster module 8 is connected to the gas phase outlet of the oil and gas processing system, and the outlet is connected to the natural gas transmission pipeline. The natural gas booster module 8 is used to boost the natural gas pressure to a specified pressure value, for example, boosting the natural gas pressure from the initial pressure P1 to the external transmission pressure P2 (meeting long-distance transmission requirements), satisfying the pressure requirements for long-distance (≥X km, where X is set according to the actual transmission distance of the oil and gas field) external transmission. The submersible screw compressor 801 also injects high-pressure gas into the production well via gas lift to produce a fluid, i.e., feedstock gas. The production fluid enters the desander through a buffer container.

[0093] The crude oil booster module 8 is an underwater positive displacement pump 802 with a twin-screw structure. The inlet of the crude oil booster module 8 is connected to the liquid phase branch of the oil and gas processing system, and the outlet is connected to the crude oil transmission pipeline. The crude oil booster module 8 is used to boost the pressure of crude oil and to perform pressurization treatment on crude oil to effectively reduce the friction resistance of crude oil in the pipeline, ensure transportation efficiency, and meet the pressure requirements for long-distance (≥X km, where X is set according to the actual transportation distance of the oil and gas field) external transportation.

[0094] In one embodiment, the pre-separation module 1 includes a cyclone desander 101, a tubular separator 102, and a gravity cyclone composite multiphase separator 103.

[0095] The raw material gas is a mixture of sand, oil, gas, and water. The feed pipe of the cyclone separator 101 is used to receive the raw material gas. The pressure chamber of the cyclone separator 101 has built-in spiral guide vanes so that the cyclone separator 101 can separate sand particles in the raw material gas using centrifugal force. The discharge pipe of the cyclone separator 101 is connected to the inlet pipe of the tubular separator 102, which performs preliminary gas-liquid separation on the raw material gas after sand removal.

[0096] The discharge pipe of the tubular separation device 102 is connected to the gravity cyclone composite multiphase separator 103. The multiphase separator chamber of the gravity cyclone composite multiphase separator 103 is divided into an upper gas phase zone, a middle liquid phase zone, and a lower water phase zone. The multiphase separator chamber has a built-in cyclone separation core so that the gravity cyclone composite multiphase separator 103 can separate the raw gas from the initial gas-liquid separation, separate the mixed gas fluid to the upper gas phase zone, separate the oil to the middle liquid phase zone, and separate the water to the lower water phase zone.

[0097] The pre-separation module 1 includes a desander, which is a cyclone desander device with a conical pressure-resistant chamber as its main body and spiral guide vanes inside. The desander is used to separate sand particles in the oil-gas-water mixture using centrifugal force. The desandered fluid enters the tubular separation device 102. The tubular separation device 102 is a tubular separator.

[0098] The pre-separation module 1 includes a tubular separation device 102. The inlet of the tubular separation device 102 is connected to the outlet of the desander, and the liquid phase outlet is connected to the inlet of the multiphase separator. The tubular separation device 102 is used to perform preliminary gas-liquid separation on the mixed fluid after desanding, and the separated liquid phase is transported to the multiphase separator.

[0099] The pre-separation module 1 includes a multiphase separator, which is a composite device integrating gravity separation and cyclone separation. The chamber is divided into an upper gas phase zone, a middle liquid phase zone, and a lower aqueous phase zone, and is equipped with a cyclone separation core inside. The inlet of the multiphase separator is connected to the liquid phase outlet of the pre-separator for fine separation of the pre-separated fluid.

[0100] This application provides a fully self-sustaining underwater oil and gas processing system, which is deployed on the seabed and includes an oil and gas processing subsystem, an oil and gas transmission subsystem, an underwater reinjection subsystem, an underwater differential pressure electronic system, an underwater AI control subsystem, and an underwater support facility subsystem 13. The subsystems are modularly integrated and work collaboratively. Each subsystem contains multiple functional modules, and the subsystems are modularly connected and operate collaboratively through underwater manifolds, power interfaces, and signal interfaces.

[0101] The oil and gas processing subsystem is integrated into a modular subsea architecture, comprising a pre-separation module 1, a dehydration module 2, a carbon dioxide removal module 3, a produced water treatment module 9, and a secondary separation module 7. The oil and gas processing subsystem adopts a progressive separation structure, sequentially completing preliminary separation, dehydration treatment, carbon dioxide removal, produced water treatment, and secondary separation.

[0102] The oil and gas transmission subsystem is connected to the output end of the oil and gas processing subsystem. It features a deep-water adapted transmission structure and is equipped with dedicated pressurization modules 8 for the different medium characteristics of natural gas and crude oil, enabling long-distance underwater transmission. The reinjection subsystem is also connected to the output end of the oil and gas processing subsystem and mainly includes a water reinjection module 12 and a carbon dioxide reinjection module 10. The underwater reinjection subsystem is used to pressurize and reinject produced water and carbon dioxide. The underwater differential pressure power generation system utilizes fluid pressure differences to generate electricity, providing stable power for the entire underwater system. This system includes an underwater expander module 4, a generator module, an energy storage module 6, and an energy management module. The underwater differential pressure power generation system uses the oil and gas fluid pressure difference to generate electricity and, in conjunction with the energy storage module 6, provides stable power to the system. The underwater AI control subsystem is deployed at various core equipment and control / monitoring points, adopting an all-electric architecture design, and includes an intelligent decision-making module and a real-time monitoring module. The underwater support facility subsystem 13 includes a flow assurance module, a chemical injection module, and an underwater foundation support module, providing basic support for the entire processing system. The underwater AI control subsystem, based on an all-electric architecture, enables intelligent monitoring and autonomous control of the system. The underwater support facility subsystem 13 provides flow assurance, chemical injection, and structural support for the long-term stable operation of the system. This invention enables underwater processing of oil and gas and energy self-sufficiency without a surface platform, offering advantages such as high system integration, strong operational reliability, and good environmental adaptability. The chemical injection module includes an underwater chemical tank.

[0103] like Figure 1 As shown, the oil and gas processing subsystem includes a pretreatment module and a staged processing module for progressively separating the sand-containing oil, gas and water mixture produced from the wellhead. The modules are connected sequentially along the fluid flow direction.

[0104] The dehydration module 2 is located on the gas phase processing branch, and its inlet is connected to the gas phase outlet of the pre-separation module 1. The dehydration module 2 is used to further dehydrate the separated gas to meet the requirements of subsequent operating conditions.

[0105] The carbon dioxide removal module 3 is located on the gas phase processing branch, and its inlet is connected to the gas phase outlet of the dehydration module 2. The carbon dioxide removal module 3 is used to remove carbon dioxide from the separated natural gas to reduce the carbon dioxide content in the gas and meet the requirements of subsequent pressurized external transmission or reinjection.

[0106] The underwater differential pressure power generation system includes an expander module 4, a generator module 5, and an energy storage module 6. The expander module 4 is located between the high-pressure fluid pipeline and the low-pressure treatment pipeline, and outputs mechanical energy under the action of fluid differential pressure. The generator module 5 is coaxially connected to the expander module 4 and converts mechanical energy into electrical energy. The energy storage module 6 is used for system startup power supply and storage of excess electrical energy.

[0107] The gas and liquid phases from the power generation module are further finely separated in the secondary separation module 7.

[0108] The oil and gas transmission subsystem is connected to the output end of the oil and gas processing subsystem and is used to pressurize and transport the separated oil and gas media. The oil and gas transmission subsystem includes an oil and gas mixing module, a natural gas pressurization module 8, and a crude oil pressurization module 8. The natural gas pressurization module 8 is located on the gas phase output pipeline. This natural gas pressurization module 8 adopts an underwater screw compressor structure 801. Its inlet is connected to the gas phase outlet of the multiphase separation module, and its outlet is connected to the natural gas transmission pipeline. It is used to pressurize the natural gas to a pressure level that meets the requirements for long-distance underwater transportation.

[0109] The crude oil booster module 8 is installed on the liquid phase output pipeline. The crude oil booster module 8 is an underwater twin-screw positive displacement pump. Its inlet is connected to the oil phase outlet of the multiphase separation module, and its outlet is connected to the crude oil transportation pipeline to reduce the friction resistance of crude oil during long-distance transportation.

[0110] The subsea reinjection subsystem is used to reinject the produced water and carbon dioxide generated during the separation process. The subsea reinjection subsystem includes a water reinjection module 12 and a carbon dioxide reinjection module 10. The water reinjection module 12 includes a reinjection booster pump, a filter, and a flow meter. After being separated by the multiphase separation module, the produced water enters the produced water branch, and after being pressurized by the filter and the reinjection booster pump, it is injected into the reinjection well through the reinjection pipeline.

[0111] The carbon dioxide reinjection module 10 includes a reinjection booster pump and a compressor. Its inlet is connected to the carbon dioxide separation branch, and its outlet is connected to the reinjection well through the carbon dioxide reinjection pipeline. It is used to compress the separated and purified carbon dioxide and inject it into the formation.

[0112] The underwater support facility subsystem 13 provides a fundamental guarantee for the long-term stable operation of the system. The underwater support facility subsystem 13 includes a flow support module, a chemical agent injection module, and an underwater foundation support module. The underwater foundation support module adopts a suction-type caisson structure, which is fixed to the seabed soil by adjusting the negative pressure inside the cylinder. The outer wall of the caisson is provided with a nickel-based alloy sacrificial anode anti-corrosion layer.

[0113] The underwater AI control subsystem is used to achieve centralized monitoring and intelligent control of the system. The specific control logic is as follows: Figure 2 As shown.

[0114] The system consists of six functional modules working together: sensors, a data processing module, an AI decision-making module, an energy management module, a control module, and actuators. The sensors are data acquisition units; the data processing module is used to transmit pre-processed standardized data; the AI ​​decision-making module is used to synchronously distribute decision instructions; the energy management module is used for energy allocation and support; the control module is used to receive instructions and execute scheduling; and the actuators are used to complete physical actions and provide feedback on the results.

[0115] The sensors, serving as the system's information input units, continuously collect the target object's state parameters (such as flow rate and temperature) and output raw data to the data processing module. This module performs preprocessing operations such as filtering, noise reduction, and normalization on the data to obtain analyzable data. This data is then sent to the AI ​​decision-making module. The AI ​​decision-making module uses a pre-set intelligent algorithm model to analyze the data, combines it with the system's pre-set control logic to generate corresponding decision commands, and simultaneously distributes these commands to the energy management module and control module. The energy management module executes internal energy allocation and power regulation operations based on the decision commands to ensure energy supply to all modules. The module generates corresponding execution commands based on the decision commands. The energy allocation and power regulation operations of the energy management module are transmitted together with the operation commands of the control module to the actuator, which then performs the corresponding physical actions (such as parameter adjustment, pressure regulation, valve opening and closing, etc.). At the same time, the actuator feeds back its execution status to the sensor, forming a closed-loop monitoring and control process for the system. In emergency scenarios, when the sensor collects abnormal data that exceeds the preset safety threshold, it can send an emergency trigger signal directly to the control module through an independent signal channel. At this time, the control module will skip the processing flow of the data processing module and the decision-making module, generate an emergency command and send it to the actuator, and simultaneously link the energy management module to prioritize the allocation of energy supply under emergency conditions, so as to realize the system's rapid response and safe handling of emergencies.

[0116] Through the above structure and their mutual cooperation, the fully self-sustaining subsea oil and gas processing system of this embodiment can complete oil and gas separation, pressurization and external transportation, by-product reinjection, energy self-sufficiency and intelligent control without the support of a sea surface platform, and is suitable for the long-term development of deep-water and ultra-deep-water oil and gas fields.

[0117] This invention provides a fully self-sufficient underwater oil and gas processing system / facility. Through innovative energy supply models, autonomous decision-making and control mechanisms, and modular underwater architecture, it achieves energy self-sufficiency, intelligent operation and maintenance, and full underwater deployment. It breaks through the dependence of traditional technologies on surface facilities, effectively reduces development costs and environmental risks, and provides key technical support for the efficient, safe, and low-carbon development of deep-sea oil and gas resources. It is applicable to fully self-sufficient underwater oil and gas processing systems in deep and ultra-deep water (water depth > 500m), especially focusing on energy self-sufficiency, autonomous control, and underwater deployment. It can get rid of dependence on surface platforms and achieve autonomous processing and stable export of underwater oil and gas throughout the entire process.

[0118] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A fully self-sustaining underwater oil and gas processing system, characterized in that, It includes a pre-separation module, an expander module, a generator module, a secondary separation module, and an oil and gas transmission module; The feed pipeline of the pre-separation module is used to receive raw gas, and the pre-separation module separates the raw gas to obtain oil, water and mixed gas fluid. The pre-separation module's mixed gas fluid discharge pipeline is connected to the expander module's inlet pipeline. The expander module is used to convert pressure energy into mechanical energy using the fluid pressure difference of the mixed gas and to further separate the mixed gas fluid. The expander module is coaxially connected to the generator module, which is used to convert mechanical energy into electrical energy; the discharge pipe of the expander module is connected to the inlet pipe of the secondary separation module, which is used to further separate the mixed gas fluid to obtain natural gas, residual oil and residual water; The oil discharge pipeline of the pre-separation module and the residual oil discharge pipeline of the secondary separation module are connected to the oil delivery pipeline of the oil and gas delivery module, so that the oil and gas delivery module can combine and deliver the oil from the pre-separation module and the residual oil from the secondary separation module; the natural gas discharge pipeline of the secondary separation module is connected to the natural gas delivery pipeline of the oil and gas delivery module, so that the oil and gas delivery module can deliver natural gas.

2. The fully self-sustaining underwater oil and gas processing system according to claim 1, characterized in that, The pre-separation module is connected to the expander module through a dehydration module and a carbon dioxide removal module; The pre-separation module's mixed gas fluid discharge pipeline is connected to the inlet pipeline of the dehydration module, which is used to remove moisture from the mixed gas fluid. The discharge pipe of the dehydration module is connected to the inlet pipe of the carbon dioxide removal module, which is used to remove carbon dioxide from the dehydrated mixed gas fluid. The mixed gas fluid discharge pipeline of the carbon dioxide removal module is connected to the expander module so that the expander module can utilize the fluid pressure difference of the mixed gas flow for dehydration and decarbonization.

3. The fully self-sustaining underwater oil and gas processing system according to claim 2, characterized in that, The subsea oil and gas processing system also includes a carbon dioxide reinjection module, which includes a carbon dioxide reinjection booster pump and a compressor. The carbon dioxide discharge pipeline of the carbon dioxide removal module is connected to the inlet pipeline of the compressor. The carbon dioxide removal module dries the carbon dioxide, and the compressor is used to pressurize the dried carbon dioxide. The discharge pipeline of the compressor is connected to the carbon dioxide reinjection booster pump. The carbon dioxide reinjection booster pump is used to pressurize the pressurized carbon dioxide for formation sealing.

4. The fully self-sustaining subsea oil and gas processing system according to claim 1, characterized in that, The underwater oil and gas processing system also includes an underwater control subsystem, which includes sensors, a data processing module, a decision-making module, an energy management module, a control module, and actuators. The sensor collects operational data from the underwater oil and gas processing system. The sensor module is connected to the data processing module, which is used to process the operating data; The data processing module is connected to the decision module, which is used to analyze the processed data and generate decision instructions. The decision-making module is connected to the energy management module, and the energy management module dynamically adjusts the energy allocation of the corresponding module according to the decision instructions; The decision module is connected to the control module, and the control module is connected to the actuator. The control module controls the actuator to adjust the corresponding module according to the decision instructions.

5. The fully self-sustaining underwater oil and gas processing system according to claim 4, characterized in that, The sensor is also connected to the control module and the energy management module. When the sensor collects abnormal data, it sends a trigger signal to the control module and the energy management module. The control module controls the actuator to adjust the abnormal module, and the energy management module allocates emergency energy to the abnormal module. And / or, the underwater oil and gas processing system also includes an intelligent flow protection module and a chemical injection module. The underwater control subsystem autonomously adjusts the heating unit temperature of the intelligent flow protection module and the chemical injection amount of the chemical injection module based on hydrate generation data.

6. The fully self-sustaining subsea oil and gas processing system according to claim 1, characterized in that, The underwater oil and gas processing system also includes an energy storage module, which is electrically connected to the generator module. The energy storage module provides initial power to the underwater oil and gas processing system and stores excess electrical energy generated by the generator module.

7. The fully self-sustaining subsea oil and gas processing system according to claim 1, characterized in that, The underwater oil and gas processing system also includes an underwater foundation support module, which adopts a suction caisson structure. The suction caisson structure is fixed to the seabed by adjusting the negative pressure. The outer wall of the caisson of the underwater foundation support module is provided with a nickel-based alloy sacrificial anode anti-corrosion layer. The underwater foundation support module is used to support the pre-separation module, the expander module, the generator module, the secondary separation module, and the oil and gas transportation module.

8. The fully self-sustaining underwater oil and gas processing system according to claim 1, characterized in that, The subsea oil and gas processing system also includes a produced water treatment module and a water reinjection module; the water discharge pipeline of the pre-separation module is connected to the inlet pipeline of the produced water treatment module, and the produced water treatment module processes the water; The water reinjection module includes a water reinjection booster pump and a filtration device; the discharge pipeline of the produced water treatment module and the residual water discharge pipeline of the secondary separation module are connected to the inlet pipeline of the filtration device; the filtration device combines and filters the treated water from the produced water treatment module and the residual water from the secondary separation module. The discharge pipeline of the filtration device is connected to a water reinjection booster pump, which is used to pressurize the filtered water for formation sealing.

9. The fully self-sustaining subsea oil and gas processing system according to claim 1, characterized in that, The pre-separation module and the secondary separation module are connected to the oil and gas transmission module via a booster module. The oil and gas transmission module includes an oil transmission module and a natural gas transmission module. The booster module includes a natural gas booster module and an oil booster module; the oil discharge pipe of the pre-separation module and the residual oil discharge pipe of the secondary separation module are connected to the inlet pipe of the oil booster module; the oil booster module uses an underwater positive displacement pump to boost the combined oil; the discharge pipe of the oil booster module is connected to the delivery pipe of the oil delivery module. The natural gas discharge pipeline of the secondary separation module is connected to the inlet pipeline of the natural gas booster module. The natural gas booster module uses a pressure-resistant sealed housing with an internal underwater screw compressor. The underwater screw compressor boosts the natural gas. The discharge pipeline of the natural gas booster module is connected to the delivery pipeline of the natural gas delivery module.

10. The fully self-sustaining subsea oil and gas processing system according to claim 1, characterized in that, The pre-separation module includes a cyclone sand separator, a tubular separation device, and a gravity cyclone composite multiphase separator. The raw material gas is a mixture of sand, oil, gas and water; The feed pipe of the cyclone separator is used to receive raw material gas. The pressure chamber of the cyclone separator has built-in spiral guide vanes so that the cyclone separator can use centrifugal force to separate sand particles in the raw material gas. The discharge pipe of the cyclone desander is connected to the inlet pipe of the tubular separator, and the tubular separator performs preliminary gas-liquid separation on the raw gas after desandering. The discharge pipe of the tubular separation device is connected to a gravity cyclone composite multiphase separator. The multiphase separator chamber of the gravity cyclone composite multiphase separator is divided into an upper gas phase zone, a middle liquid phase zone, and a lower water phase zone. The multiphase separator chamber has a built-in cyclone separation core so that the gravity cyclone composite multiphase separator can separate the raw gas from the initial gas-liquid separation, separating the mixed gas fluid to the upper gas phase zone, separating the oil to the middle liquid phase zone, and separating the water to the lower water phase zone.

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