A subsea oil production tree and its control method

Abstract

This invention discloses a subsea wellhead and its control method, belonging to the technical field of subsea oil and gas extraction equipment. The wellhead includes a main frame composed of columns and a top plate, with a vertical main channel in the middle, a detection box fixed on the outer wall, and an internal detection mechanism. The fluid passage of the main channel is connected in series with an electrically controlled throttle valve group and a downhole safety shut-off valve. The system is equipped with an oil production monitoring system and an underwater redundant communication unit, which can collect pressure and temperature parameters, generate operating status feature values ​​through preprocessing, normalization, and multi-parameter fusion calculation, and output opening adjustment, opening correction, or emergency shutdown commands through three-level threshold comparison to achieve local closed-loop control. The detection box is equipped with a sealing plate and a barrier plate to form a double layer of protection, and the detection mechanism adopts a detachable structure. The communication unit supports automatic switching between primary and backup links and breakpoint resume transmission. This invention solves the problems of poor protection, cumbersome maintenance, and low control reliability of existing wellhead detection mechanisms, and improves the equipment's operational stability, monitoring accuracy, and maintenance convenience.

Description

Technical Field

[0001] This invention relates to the field of subsea wellhead technology, and more particularly to a subsea wellhead and its control method. Background Technology

[0002] Subsea wellheads are the core control equipment of subsea oil and gas extraction systems, used to control oil and gas flow, regulate flow, and control pressure. Their operational stability and monitoring reliability directly affect the efficiency and safety of oil and gas field extraction. Existing subsea wellheads mainly consist of a main frame, vertical main channel, valves, and sealing structures. They transport oil and gas through the vertical main channel and isolate the wellbore from the seawater environment through the sealing structures, meeting the oil and gas extraction requirements under high-pressure conditions on the seabed.

[0003] Existing subsea production trees with detection capabilities generally place the detection sensors directly in the seawater environment. The detection facilities do not have dedicated sealing and protection structures. They are subject to long-term seawater corrosion and seabed pressure impacts, which can easily lead to sensor failure, distorted monitoring data, and other problems, making it impossible to stably reflect the actual operating status of the production tree.

[0004] The existing subsea production trees use a fixed installation structure for inspection. Disassembly and maintenance require large surface support vessels and heavy machinery, resulting in complex operation procedures, high maintenance costs, and low efficiency at sea, which affects the continuity of oil and gas production. At the same time, the existing subsea production trees only have data upload functions and lack local computing and autonomous control logic. They rely entirely on commands issued by the surface control terminal, resulting in delayed control response and potential safety risks when communication is interrupted. In addition, the existing subsea production trees have no redundant communication links, leading to poor transmission stability under complex subsea conditions. Furthermore, the actuators lack redundant protection, meaning that a single component failure can cause flow regulation failure, further reducing the reliability of the equipment. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by proposing a subsea oil production tree and its control method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a subsea production tree, comprising a main frame, wherein the main frame is composed of columns and a top plate fixedly connected together, a vertical main channel is vertically installed through the middle of the main frame via a fixing rod, a detection box is fixedly connected to the outer wall of the vertical main channel, and a detection mechanism for real-time monitoring of the subsea production tree's operating status is assembled inside the detection box; an electrically controlled throttle valve group and a downhole safety shut-off valve are connected in series on the fluid passage of the vertical main channel, and the detection mechanism is signal-connected to the electrically controlled throttle valve group and the downhole safety shut-off valve respectively; The system also includes an oil production monitoring system. This system collects pressure and temperature parameters inside the vertical main channel according to a preset sampling cycle. The collected parameters undergo amplification, filtering, and analog-to-digital conversion preprocessing. The preprocessed parameters are then subjected to normalized multi-parameter fusion calculations to generate characteristic values ​​of the tree's operating status. These characteristic values ​​are compared with preset three-level threshold intervals to generate corresponding control commands. The three-level threshold intervals include a normal threshold interval, a warning threshold interval, and an interlocking threshold interval. When the characteristic value is within the normal threshold interval, an opening adjustment command is generated. When the characteristic value is within the warning threshold interval, an opening correction command is generated. When the characteristic value is within the interlocking threshold interval, an emergency shutdown command is generated. The system executes corresponding operations based on the control commands at the corresponding level. Furthermore, an underwater redundant communication unit is configured for bidirectional data interaction with the surface control terminal. This underwater redundant communication unit monitors the connectivity and transmission error rate of the main communication link in real time. When the main communication link is interrupted or the error rate exceeds a preset threshold, it automatically switches to the backup communication link to complete data transmission and command interaction.

[0007] Preferably, the detection mechanism includes four threaded fixing cylinders, a circuit board, a pressure sensor, and a temperature sensor. The four threaded fixing cylinders are fixedly connected to the inner bottom surface of the detection box in a rectangular array. The circuit board is detachably connected to the four threaded fixing cylinders by bolts. Two threaded holes are horizontally opened above the circuit board. The two threaded holes pass through the detection box and the vertical main channel at the same position. The pressure sensor and the temperature sensor are respectively assembled in the two threaded holes by threaded connection, and the sensor detection end extends into the interior of the vertical main channel.

[0008] Preferably, the top of the detection box has an opening communicating with the interior, and a sealing plate is fitted into the opening. The sealing plate is sealed to the edge of the opening of the detection box by sealant.

[0009] Preferably, a barrier plate is detachably installed on the top of the detection box outside the sealing plate. The barrier plate is fixedly connected to the detection box by fixing bolts, and the barrier plate completely covers the sealing plate.

[0010] Preferably, the circuit board integrates a signal processing module and a data transmission module. The pressure sensor and temperature sensor are both electrically connected to the signal processing module, and the signal processing module is electrically connected to the data transmission module for transmitting monitoring data to the sea surface control terminal.

[0011] Preferably, the circuit board also integrates a data processing module, a valve group control module, and a safety interlock module; the signal processing module amplifies, filters, and performs analog-to-digital conversion on the collected pressure and temperature parameters, and outputs standardized digital signals to the data processing module; the data processing module performs normalization processing and multi-parameter fusion calculation on the standardized digital signals to generate operating status feature values, compares the operating status feature values ​​with preset thresholds, and outputs flow regulation commands to the valve group control module, interlock trigger commands to the safety interlock module, and operating data to the underwater redundant communication unit; the valve group control module generates corresponding drive signals according to the flow regulation commands to control the electrically controlled throttle valve group to perform opening adjustment; the safety interlock module generates corresponding drive signals according to the interlock trigger commands to control the downhole safety shut-off valve to perform on / off actions.

[0012] Preferably, the data processing module includes a parameter threshold storage unit, a multi-parameter fusion processing unit, a fault self-diagnosis unit, and a remaining life prediction unit. The parameter threshold storage unit stores the normal, early warning, and interlocking three-level pressure thresholds, temperature thresholds, pressure change rate thresholds, and temperature change rate thresholds corresponding to the vertical main channel. The multi-parameter fusion processing unit performs dimensionless normalization processing on the real-time collected pressure and temperature data, performs weighted fusion processing according to preset weight coefficients, and generates one-dimensional operating status feature values. The fault self-diagnosis unit compares the operating status feature values ​​with the three-level threshold intervals one by one, matches the corresponding fault level, and outputs control commands that match the fault level. The remaining life prediction unit uses the cumulative running time, operating condition fluctuation frequency, and parameter over-threshold duration as input variables, calculates and outputs the remaining life data of the core components through a pre-trained life prediction model.

[0013] Preferably, the underwater redundant communication unit includes a main communication link, a backup communication link, a link status detection submodule, and an automatic switching submodule; the main communication link adopts an underwater optical-electric composite cable wired communication link, and the backup communication link adopts an underwater acoustic communication link; the link status detection submodule collects the signal strength, transmission connectivity, and data error rate of the main communication link at a preset period; when the signal strength of the main communication link is lower than a preset threshold, transmission is interrupted, or the error rate exceeds a preset threshold, the automatic switching submodule triggers a link switching action, suspends the data transmission of the main communication link, caches the data to be transmitted to the local storage unit, and enables the backup communication link to complete the data transmission and command interaction; when the main communication link returns to normal and remains so for a preset duration, the automatic switching submodule switches the data transmission link back to the main communication link and synchronously transmits the cached interrupted data.

[0014] Preferably, the electrically controlled throttle valve assembly includes at least two electrically controlled proportional throttle valves connected in series; each electrically controlled proportional throttle valve is equipped with a valve position feedback unit and a differential pressure detection unit; the valve position feedback unit collects the actual valve core opening data of the electrically controlled proportional throttle valve in real time, and the differential pressure detection unit collects the pressure data before and after the valve in real time and calculates the differential pressure; the detection mechanism receives the actual valve core opening data and the differential pressure data, compares the actual opening data with the commanded opening data to generate an opening deviation value, and corrects the opening adjustment command in combination with the differential pressure data, driving the electrically controlled proportional throttle valve to adjust the valve core opening, forming a single-valve flow closed-loop regulation circuit; the two electrically controlled proportional throttle valves connected in series operate in a preset master / standby mode, with the master valve performing daily flow regulation, and automatically switching to the standby valve to perform flow regulation when the master valve fails.

[0015] This invention also proposes a method for controlling a subsea production tree, based on the aforementioned subsea production tree implementation, comprising the following steps: S1 collects pressure and temperature data in the vertical main channel, valve position and differential pressure data of the electronically controlled throttle valve group, and on / off status data of the downhole safety shut-off valve according to a preset cycle. S2 performs amplification, filtering, analog-to-digital conversion, and dimensionless normalization on all collected data to generate standardized operating data; S3 performs weighted multi-parameter fusion calculations on standardized operating data to generate operating status feature values. It then compares these operating status feature values ​​with preset three-level threshold ranges to match the corresponding fault levels and generate corresponding control commands. When the operating status characteristic value of S4 is in the normal range, it drives the electronically controlled throttle valve group to perform flow closed-loop regulation according to the control command; when it is in the warning range, it drives the electronically controlled throttle valve group to perform opening correction; when it is in the interlock range, it drives the downhole safety shut-off valve to perform emergency shutdown; and simultaneously uploads the operating data to the surface control terminal to receive and execute remote control commands. S5 monitors the status of the main communication link in real time and automatically switches to the backup communication link to complete data interaction when the main link is abnormal. S6 transmits the adjusted real-time operating data back to the sea surface control terminal to complete single-cycle closed-loop control.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. This solution forms a layered, sealed protective structure through a detection box, sealing plate, and barrier plate. Combined with corrosion-resistant alloy material and a waterproof and anti-corrosion coating, it isolates the detection mechanism from the seawater environment, solving the problems of existing wellhead sensors being susceptible to seawater corrosion, pressure shock leading to malfunction, and data distortion. The detection mechanism adopts a detachable assembly structure, which allows for independent disassembly and assembly of circuit boards, pressure sensors, and temperature sensors without the need for large-scale surface operation equipment. This reduces the complexity of maintenance procedures and operating costs, and improves the assembly and maintenance efficiency of the detection mechanism.

[0017] 2. This solution utilizes an oil production monitoring system to acquire, preprocess, normalize, and perform multi-parameter fusion calculations on pressure and temperature data. Combined with three-level threshold ranges, it generates corresponding control commands to complete flow regulation, opening correction, and emergency shutdown actions. This addresses the shortcomings of existing subsea production trees, which can only upload data and lack local autonomous control. The system can independently complete status judgment and action execution without relying on real-time commands from the surface control terminal, improving the response speed of subsea production tree operation control and reducing the safety risks caused by communication delays and interruptions.

[0018] 3. This solution achieves automatic switching between the main and backup communication links through underwater redundant communication units, combined with local data caching and breakpoint resume transmission, to maintain the continuity of data transmission and command interaction, thus solving the problem of poor communication stability under complex seabed conditions; the electrically controlled throttle valve group adopts a main and backup valve operation mode, and forms a closed-loop flow regulation by combining valve position feedback and differential pressure detection. When the main valve fails, the backup valve is automatically switched to maintain the flow regulation function, thereby improving the continuous operation capability and control reliability of the wellhead.

[0019] In summary, this solution simultaneously achieves sealed protection and convenient maintenance of the testing mechanism, autonomous monitoring and hierarchical control of operational status, and redundant protection of communication and actuators. It solves the problems of insufficient protection, cumbersome maintenance, lagging control, and unreliable communication in existing subsea production trees, improves equipment operational stability, control security, and maintenance convenience, and extends equipment service life. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the overall three-dimensional structure proposed in this invention; Figure 2 This is a schematic diagram of the overall three-dimensional structure of the other side proposed in this invention; Figure 3 This is a schematic diagram of the front view structure proposed in this invention; Figure 4 This is a schematic diagram of the three-dimensional structure proposed in this invention from a bottom-view perspective; Figure 5 This is a schematic diagram of the three-dimensional structure of the detection box proposed in this invention; Figure 6 This is a three-dimensional structural diagram of the first partial detection box proposed in this invention; Figure 7 This is a schematic diagram of the three-dimensional structure of the second partial detection box proposed in this invention; Figure 8 This is a top-view schematic diagram of a partial three-dimensional structure of the detection box proposed in this invention; Figure 9 This is a block diagram illustrating the overall principle of the oil production monitoring system proposed in this invention. Figure 10 This is a block diagram of the working logic of the underwater redundant communication unit proposed in this invention. Figure 11 This is a flowchart of the control method proposed in this invention.

[0021] The markings in the diagram are: 1. Column; 2. Top plate; 3. Vertical main channel; 4. Detection box; 5. Barrier plate; 6. Sealing plate; 7. Pressure sensor; 8. Temperature sensor; 9. Circuit board. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0023] See Figures 1 to 8 The present invention discloses a subsea production tree, comprising a main frame consisting of columns 1 and a top plate 2 fixedly connected together. A vertical main channel 3 is vertically installed through the middle of the main frame via a fixing rod. A detection box 4 is fixedly connected to the outer wall of the vertical main channel 3. The detection box 4 is equipped with a detection mechanism for real-time monitoring of the operating status of the subsea production tree. Through the columns 1, top plate 2, vertical main channel 3, detection box 4, and detection mechanism, the main structure of the subsea production tree is easily constructed, and the construction and real-time monitoring of the oil production channel are realized.

[0024] Reference Figures 2 to 8As shown, the detection mechanism includes four threaded fixing cylinders, a circuit board 9, a pressure sensor 7, and a temperature sensor 8. The four threaded fixing cylinders are fixedly connected to the inner bottom surface of the detection box 4 in a rectangular array. The circuit board 9 is detachably connected to the four threaded fixing cylinders by bolts. Two threaded holes are horizontally opened on the top of the circuit board 9. The two threaded holes pass through the detection box 4 and the vertical main channel 3 at the same position. The pressure sensor 7 and the temperature sensor 8 are respectively assembled in the two threaded holes by threaded connection, and the sensor detection end extends into the interior of the vertical main channel 3. The circuit board 9 is easily fixed by the threaded fixing cylinders, the circuit board 9, the pressure sensor 7, the temperature sensor 8, the detection box 4, and the vertical main channel 3, and the pressure and temperature in the vertical main channel 3 are monitored in real time.

[0025] Reference Figures 5 to 6 As shown, the top of the detection box 4 has an opening communicating with the interior. A sealing plate 6 is fitted into the opening and is sealed to the edge of the opening of the detection box 4 with sealant. The detection box 4, sealing plate 6, and sealant facilitate sealing of the internal components of the detection box 4 and prevent seawater from entering and causing damage. A barrier plate 5 is detachably installed on the top of the detection box 4 outside the sealing plate 6. The barrier plate 5 is fixedly connected to the detection box 4 with fixing bolts and completely covers the sealing plate 6. The detection box 4, barrier plate 5, fixing bolts, and sealing plate 6 facilitate protection of the sealing plate 6 and enhance the sealing stability of the detection box 4.

[0026] Reference Figure 1 and Figure 8 As shown, circuit board 9 integrates a signal processing module and a data transmission module. Pressure sensor 7 and temperature sensor 8 are electrically connected to the signal processing module, which in turn is electrically connected to the data transmission module. This allows the monitoring data to be transmitted to the sea surface control terminal. Circuit board 9, signal processing module, data transmission module, pressure sensor 7, and temperature sensor 8 facilitate the processing of monitoring data and the transmission of the data to the sea surface control terminal. Column 1, top plate 2, vertical main channel 3, and detection box 4 are all made of corrosion-resistant alloy material. Detection box 4 is coated with a waterproof and anti-corrosion coating. Column 1, top plate 2, vertical main channel 3, and detection box 4 enhance the corrosion resistance and waterproofness of the wellhead.

[0027] Reference Figure 9 As shown, the subsea production tree proposed in this invention is also equipped with an oil production monitoring system; the oil production monitoring system is bidirectionally connected to the detection mechanism, the electrically controlled throttle valve group, the downhole safety shut-off valve, and the underwater redundant communication unit; the oil production monitoring system performs the following steps: Step a: Collect the pressure parameter P(t) and temperature parameter T(t) inside the vertical main channel 3 according to the preset sampling period T. Perform amplification, filtering, and analog-to-digital conversion preprocessing on the collected parameters. Perform min-max dimensionless normalization on the preprocessed parameters. The normalization formula is: In the formula, Let P(t) be the pressure parameter or T(t) collected at time t. , These are the upper and lower limits of the range for the corresponding parameters, respectively. Step b: Perform a weighted multi-parameter fusion calculation on the normalized pressure and temperature parameters to generate the characteristic value S(t) of the wellhead operating state. The fusion calculation formula is as follows: In the formula, , , , Let represent the weighting coefficients for normalized pressure, normalized temperature, normalized pressure change rate, and normalized temperature change rate, respectively, and satisfy . , Δ is the difference between the normalized pressure at time t and time t-1. This represents the difference between the normalized temperatures at time t and time t-1. Step c: Compare the running state characteristic value S(t) with the preset three-level threshold range to generate control instructions of the corresponding level; wherein, the three-level threshold range includes the normal threshold range. Warning threshold range Interlocking threshold range , The minimum value of the eigenvalue. The maximum value of the eigenvalue. As the warning threshold, This is the interlocking threshold; when When, generate an opening adjustment command; when When, generate an opening correction instruction; when At that time, an emergency shutdown command is generated; Step d: Drive the electrically controlled throttle valve assembly or downhole safety shut-off valve to perform the corresponding operation according to the control command of the corresponding level; Reference Figure 10 As shown, the present invention also includes an underwater redundant communication unit for bidirectional data interaction with the surface control terminal. The underwater redundant communication unit monitors the connectivity status and bit error rate (BER) of the main communication link in real time. When the main communication link is interrupted or the BER exceeds a preset BER threshold, the system will initiate a response. When necessary, it automatically switches to the backup communication link to complete data transmission and command interaction.

[0028] Furthermore, circuit board 9 also integrates a data processing module, a valve group control module, and a safety interlock module; The signal processing module performs adaptive moving average filtering on the acquired pressure parameter P(t) and temperature parameter T(t). The filtering formula is as follows: In the formula, Here are the filtered parameter values, and N is the sliding window length. is the adaptive weighting coefficient for the i-th sampling point within the window. The weighting coefficient is dynamically adjusted according to the deviation between the sampling value and the window mean; the larger the deviation, the smaller the weight. The signal processing module performs analog-to-digital conversion on the filtered parameters and outputs a standardized digital signal to the data processing module. The data processing module performs normalization processing and weighted multi-parameter fusion calculation on the standardized digital signal to generate the operating status feature value S(t). After comparing the operating status feature value S(t) with the preset threshold, it outputs the flow regulation command to the valve group control module, the interlock trigger command to the safety interlock module, and the operating data to the underwater redundant communication unit. The valve group control module generates corresponding drive signals based on the flow regulation command using an incremental PID algorithm, and controls the electronically controlled throttle valve group to perform opening adjustment. The formula for the incremental PID algorithm is: In the formula, This represents the opening adjustment increment for the k-th control cycle. This is the proportionality coefficient. The integral coefficient is... The differential coefficients are... This represents the deviation between the target opening and the actual opening in the k-th control cycle. The safety interlock module generates a corresponding drive signal based on the interlock trigger command, controlling the downhole safety shut-off valve to perform on / off actions. The logic formula for interlock triggering is as follows: In the formula, To trigger an emergency shutdown, in This is the normal on / off state. This is the upper limit of pressure protection. This is the upper limit of temperature protection.

[0029] Furthermore, the data processing module includes a parameter threshold storage unit, a multi-parameter fusion processing unit, a fault self-diagnosis unit, and a remaining life prediction unit; The parameter threshold storage unit stores the normal, warning, and interlocking three-level pressure thresholds, temperature thresholds, pressure change rate thresholds, and temperature change rate thresholds corresponding to the vertical main channel 3. Among them, the warning threshold... Interlocking threshold pass The criteria are determined by calculation, and the calculation formula is as follows: In the formula, Let S(t) be the mathematical expectation of the characteristic value S(t) of the oil well tree under normal operating conditions. This represents the standard deviation of S(t) under normal operating conditions. The multi-parameter fusion processing unit performs dimensionless normalization on the real-time acquired pressure and temperature data, and performs weighted fusion calculations using weight coefficients optimized by the analytic hierarchy process (AHP) to generate a one-dimensional operating state feature value S(t). The weight coefficient optimization formula is as follows: In the formula, Let be the weight coefficient of the i-th parameter, and n be the number of parameters participating in the fusion. To determine the importance scale value of the i-th parameter relative to the j-th parameter in the matrix, the judgment matrix is ​​constructed using the 1-9 scaling method; The fault self-diagnosis unit compares the operating state characteristic value S(t) with the three-level threshold intervals one by one, matches the corresponding fault level through a fuzzy membership function, and outputs a control command matching the fault level. The fuzzy membership function adopts a normal distribution function, and the formula is as follows: In the formula, Let S be the membership degree of the m-th fault level corresponding to the operating state characteristic value S. The eigenvalue center value corresponding to the m-th fault level is... Let m be the standard deviation of the eigenvalue distribution corresponding to the m-th fault level; The remaining life prediction unit uses the cumulative running time t, the frequency of operating condition fluctuations f, and the duration of parameter exceeding the threshold as parameters. Using the three-parameter Weibull distribution model as input variables, the remaining lifetime (RUL) of the core component is calculated and output. The reliability function of the three-parameter Weibull distribution is: In the formula, R(t) represents the reliability of the component during operating time t. For position parameters (minimum lifetime). This is the scale parameter (feature lifetime). For shape parameters; The formula for calculating the remaining useful life (RUL) is: In the formula, The preset minimum permissible reliability, This represents the current cumulative runtime of the component.

[0030] Furthermore, the underwater redundant communication unit includes a main communication link, a backup communication link, a link status detection submodule, an automatic switching submodule, and a local data buffer unit; the main communication link adopts an underwater optical-electric composite cable wired communication link, and the backup communication link adopts an underwater acoustic communication link. The link status detection submodule collects the signal strength RSSI, transmission connectivity, and bit error rate (BER) of the main communication link at preset intervals, and calculates the link health index H. The link health calculation formula is as follows: In the formula, , These are the signal strength weight and the bit error rate weight, respectively. RSSI represents the current main link signal strength. The minimum permissible signal strength; BER is the current main link bit error rate. The maximum permissible bit error rate; The closer H is to 1, the better the link status; The automatic switching submodule uses hysteresis control logic to perform link switching. The switching logic formula is as follows: In the formula, To switch to the backup communication link, To switch back to the main communication link; To switch the lower threshold, To switch back to the upper limit threshold, and ; The threshold for the duration of state retention; When a link switching action is triggered, the automatic switching submodule suspends the main communication link data transmission, caches the data to be transmitted to the local data cache unit, and enables the backup communication link to complete data transmission and command interaction. When the main communication link returns to normal and continues for a preset time, the automatic switching submodule switches the data transmission link back to the main communication link and synchronously transmits the cached breakpoint data. The breakpoint data transmission specifically uses CRC cyclic redundancy check to ensure data integrity.

[0031] Furthermore, the electronically controlled throttle valve assembly includes at least two electronically controlled proportional throttle valves arranged in series, defined as the main throttle valve and the standby throttle valve, respectively; each electronically controlled proportional throttle valve is equipped with a valve position feedback unit and a differential pressure detection unit across the valve. The valve position feedback unit collects the actual valve core opening data L(t) of the electronically controlled proportional throttle valve in real time. The differential pressure detection unit collects the upstream pressure P1(t) and downstream pressure P2(t) of the electronically controlled proportional throttle valve in real time, calculates the pressure difference ΔP(t) = P1(t) - P2(t), and calculates the real-time flow rate Q(t) using the throttle valve flow rate formula. The flow rate calculation formula is as follows: In the formula, The preset flow coefficient is determined by the throttle valve structure calibration; Valve core opening The corresponding throttling orifice flow area; The density of the transported medium; After receiving the actual valve opening data L(t), differential pressure data ΔP(t), and real-time flow data Q(t), the actual flow rate Q(t) is compared with the target flow rate Q_sp to generate the flow deviation. The fuzzy PID algorithm is used to correct the opening adjustment command based on the flow deviation, driving the electronically controlled proportional throttle valve to adjust the valve core opening, forming a single-valve flow closed-loop regulation loop; the adaptive correction formula for the fuzzy PID parameters is as follows: , , In the formula, , , The initial values ​​of the parameters preset for the PID controller. , , This is the maximum adjustment amount of the parameter. , , For the fuzzy membership degree of the corresponding parameter, For flow deviation, The rate of change of flow deviation; Two series-connected electronically controlled proportional throttle valves operate in a preset master / standby mode. The master throttle valve performs daily flow regulation, and the failure rate F of the master throttle valve is calculated in real time. The failure rate calculation formula is as follows: In the formula, , These are the valve position deviation weight and the flow rate deviation weight, respectively. ; This is the actual opening. For instruction opening, This is the maximum opening. This represents the actual traffic volume. For instruction traffic, This is the rated maximum flow rate; When the main throttle valve failure degree F exceeds the preset failure threshold When necessary, it automatically switches to the standby throttle valve to perform flow regulation.

[0032] Reference Figure 11 As shown, the present invention also proposes a method for controlling a subsea production tree, which is based on the above-mentioned subsea production tree and includes the following steps: S1 collects pressure and temperature data in the vertical main channel 3 according to a preset cycle, collects valve position data and differential pressure data of the electronically controlled throttle valve group, and collects the on / off status data of the downhole safety shut-off valve. S2 performs amplification, filtering, analog-to-digital conversion, and dimensionless normalization on all collected data to generate standardized operating data; S3 performs weighted multi-parameter fusion calculations on standardized operating data to generate operating status feature values. It then compares these operating status feature values ​​with preset three-level threshold ranges to match the corresponding fault levels and generate corresponding control commands. When the operating status characteristic value of S4 is in the normal range, it drives the electronically controlled throttle valve group to perform flow closed-loop regulation according to the control command; when it is in the warning range, it drives the electronically controlled throttle valve group to perform opening correction; when it is in the interlock range, it drives the downhole safety shut-off valve to perform emergency shutdown; and simultaneously uploads the operating data to the surface control terminal to receive and execute remote control commands. S5 monitors the status of the main communication link in real time and automatically switches to the backup communication link to complete data interaction when the main link is abnormal. S6 transmits the adjusted real-time operating data back to the sea surface control terminal to complete single-cycle closed-loop control.

[0033] The working principle of the subsea oil production tree and control method proposed in this invention is as follows: The main frame is formed by the fixed connection between the column 1 and the top plate 2, providing structural support for the subsea production tree. The vertical main channel 3 is used for the transportation of oil and gas media. Pressure sensor 7 and temperature sensor 8 collect pressure and temperature data inside the vertical main channel 3 in real time and transmit the collected signals to the signal processing module on the circuit board 9. The signal processing module amplifies, filters, and performs analog-to-digital conversion on the collected signals, outputting standardized digital signals to the data processing module. The data processing module normalizes the standardized digital signals and performs multi-parameter fusion calculations to generate operating status feature values. It compares the operating status feature values ​​with preset three-level threshold ranges, generates corresponding control commands, and outputs them to the valve group control module and the safety interlock module, respectively. At the same time, it transmits the operating data to the underwater redundant communication unit. The valve group control module drives the electrically controlled throttle valve group to perform opening adjustment according to the received control commands, realizing the flow control of oil and gas media. The safety interlock module drives the downhole safety shut-off valve to perform on / off actions according to the received interlock commands, realizing emergency shutdown.

[0034] The underwater redundant communication unit uploads operational status data to the surface control terminal and receives remote control commands from the surface control terminal, transmitting them to the corresponding execution modules. The link status detection submodule monitors the transmission status of the main communication link in real time. When the main communication link malfunctions, the automatic switching submodule switches to the backup communication link for data exchange, while storing the data to be transmitted in the local storage unit. After the main communication link recovers, the system automatically resumes the transmission of interrupted data. The valve position feedback unit and differential pressure detection unit configured in the electronically controlled throttle valve assembly collect valve core opening data and differential pressure data across the valve in real time and feed them back to the signal processing module, forming a flow closed-loop regulation circuit. When the main throttle valve fails, the system automatically switches to the backup throttle valve to perform flow regulation operations.

[0035] The detection box 4, sealing plate 6, and barrier plate 5 work together to form a sealed protective structure, preventing seawater from entering the interior of the detection box 4. The circuit board 9 is connected to the threaded fixing cylinder inside the detection box 4 by bolts. The circuit board 9, pressure sensor 7, and temperature sensor 8 can be disassembled and maintained by removing the barrier plate 5 and sealing plate 6. The data processing module performs fault diagnosis and remaining life calculation based on the collected operating data and operating condition fluctuation data, outputs fault level signals and remaining life data of core components, and uploads them to the surface control terminal through the underwater redundant communication unit.

[0036] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A subsea production tree, comprising a main frame, wherein the main frame is composed of columns (1) and a top plate (2) fixedly connected, characterized in that: A vertical main channel (3) is vertically installed through the middle of the main frame via a fixed rod. A detection box (4) is fixedly connected to the outer wall of the vertical main channel (3). The detection box (4) is equipped with a detection mechanism for real-time monitoring of the operation status of the subsea tree. An electrically controlled throttle valve group and a downhole safety shut-off valve are connected in series on the fluid passage of the vertical main channel (3). The detection mechanism is connected to the electrically controlled throttle valve group and the downhole safety shut-off valve respectively. It is also equipped with an oil production monitoring system; the oil production monitoring system is used to collect pressure and temperature parameters inside the vertical main channel (3) according to a preset sampling cycle, perform amplification, filtering and analog-to-digital conversion preprocessing on the collected parameters, and perform normalization multi-parameter fusion calculation on the preprocessed parameters to generate oil production tree operation status characteristic values; The system compares the operating status characteristic values ​​with preset three-level threshold ranges to generate corresponding control commands. These three threshold ranges include a normal threshold range, a warning threshold range, and an interlocking threshold range. When the operating status characteristic value is within the normal threshold range, an opening adjustment command is generated; when it is within the warning threshold range, an opening correction command is generated; and when it is within the interlocking threshold range, an emergency shutdown command is generated. The system then executes corresponding operations based on the control commands at each level. Furthermore, an underwater redundant communication unit is configured for bidirectional data interaction with the surface control terminal. This unit continuously monitors the connectivity and bit error rate of the main communication link. When the main communication link is interrupted or the bit error rate exceeds a preset threshold, it automatically switches to the backup communication link to complete data transmission and command interaction.

2. The subsea oil production tree according to claim 1, characterized in that: The detection mechanism includes four threaded fixed cylinders, a circuit board (9), a pressure sensor (7), and a temperature sensor (8). The four threaded fixed cylinders are fixedly connected in a rectangular array to the inner bottom surface of the detection box (4). The circuit board (9) is detachably connected to the four threaded fixed cylinders by bolts. Two threaded holes are horizontally opened above the circuit board (9). The two threaded holes pass through the detection box (4) and the vertical main channel (3) at the same position. The pressure sensor (7) and the temperature sensor (8) are respectively assembled in the two threaded holes by threaded connection, and the sensor detection end extends into the vertical main channel (3).

3. The subsea oil production tree according to claim 2, characterized in that: The top of the detection box (4) has an opening that communicates with the interior. A sealing plate (6) is fitted into the opening, and the sealing plate (6) is sealed to the edge of the opening of the detection box (4) with sealant.

4. The subsea oil production tree according to claim 3, characterized in that: The top of the detection box (4) is located outside the sealing plate (6) and a barrier plate (5) is detachably installed. The barrier plate (5) is fixedly connected to the detection box (4) by fixing bolts and the barrier plate (5) completely covers the sealing plate (6).

5. A subsea oil production tree according to claim 2, characterized in that: The circuit board (9) integrates a signal processing module and a data transmission module. The pressure sensor (7) and temperature sensor (8) are both electrically connected to the signal processing module. The signal processing module is electrically connected to the data transmission module and is used to transmit monitoring data to the sea surface control terminal.

6. The subsea oil production tree according to claim 5, characterized in that: The circuit board (9) also integrates a data processing module, a valve group control module, and a safety interlock module; the signal processing module performs amplification, filtering, and analog-to-digital conversion processing on the collected pressure and temperature parameters, and outputs standardized digital signals to the data processing module; the data processing module performs normalization processing and multi-parameter fusion calculation on the standardized digital signals, generates operating status feature values, compares the operating status feature values ​​with preset thresholds, and outputs flow regulation commands to the valve group control module, interlock trigger commands to the safety interlock module, and operating data to the underwater redundant communication unit; The valve group control module generates a corresponding drive signal according to the flow regulation command, and controls the electrically controlled throttle valve group to perform opening adjustment; the safety interlock module generates a corresponding drive signal according to the interlock trigger command, and controls the downhole safety shut-off valve to perform on / off action.

7. A subsea oil production tree according to claim 6, characterized in that: The data processing module includes a parameter threshold storage unit, a multi-parameter fusion processing unit, a fault self-diagnosis unit, and a remaining life prediction unit. The parameter threshold storage unit stores the normal, early warning, and interlocking three-level pressure thresholds, temperature thresholds, pressure change rate thresholds, and temperature change rate thresholds corresponding to the vertical main channel (3). The multi-parameter fusion processing unit performs dimensionless normalization processing on the real-time collected pressure data and temperature data, performs weighted fusion processing according to preset weight coefficients, and generates one-dimensional operating status feature values. The fault self-diagnosis unit compares the operating status feature values ​​with the three-level threshold intervals one by one, matches the corresponding fault level, and outputs control commands that match the fault level. The remaining life prediction unit uses the cumulative running time, operating condition fluctuation frequency, and parameter over-threshold duration as input variables, calculates and outputs the remaining life data of the core components through a pre-trained life prediction model.

8. A subsea oil production tree according to claim 1, characterized in that: The underwater redundant communication unit includes a main communication link, a backup communication link, a link status detection submodule, and an automatic switching submodule; the main communication link adopts an underwater optical-electric composite cable wired communication link, and the backup communication link adopts an underwater acoustic communication link; the link status detection submodule collects the signal strength, transmission connectivity status, and data error rate of the main communication link at a preset period. When the signal strength of the main communication link is lower than the preset threshold, transmission is interrupted, or the bit error rate exceeds the preset threshold, the automatic switching submodule triggers the link switching action, suspends the data transmission of the main communication link, caches the data to be transmitted to the local storage unit, and enables the backup communication link to complete the data transmission and command interaction. Once the main communication link returns to normal and continues for a preset duration, the automatic switching submodule will switch the data transmission link back to the main communication link and synchronously transmit the cached breakpoint data.

9. A subsea oil production tree according to claim 1, characterized in that: The electrically controlled throttle valve assembly includes at least two electrically controlled proportional throttle valves connected in series. Each electrically controlled proportional throttle valve is equipped with a valve position feedback unit and a differential pressure detection unit. The valve position feedback unit collects the actual valve core opening data of the electrically controlled proportional throttle valve in real time, and the differential pressure detection unit collects the pressure data before and after the valve in real time and calculates the differential pressure. The detection mechanism receives the actual valve core opening data and the differential pressure data, compares the actual opening data with the commanded opening data to generate an opening deviation value, and corrects the opening adjustment command in combination with the differential pressure data, driving the electrically controlled proportional throttle valve to adjust the valve core opening, forming a single-valve flow closed-loop regulation circuit. The two electrically controlled proportional throttle valves connected in series operate in a preset master / standby mode. The master valve performs daily flow regulation, and when the master valve fails, it automatically switches to the standby valve to perform flow regulation.

10. A method for controlling a subsea oil production tree, characterized in that, The implementation based on the subsea production tree according to any one of claims 1 to 9 includes the following steps: S1 collects pressure data and temperature data in the vertical main channel (3) according to a preset cycle, collects valve position data and differential pressure data of the electrically controlled throttle valve group, and collects the on / off status data of the downhole safety shut-off valve. S2 performs amplification, filtering, analog-to-digital conversion, and dimensionless normalization on all collected data to generate standardized operating data; S3 performs weighted multi-parameter fusion calculations on standardized operating data to generate operating status feature values. It then compares these operating status feature values ​​with preset three-level threshold ranges to match the corresponding fault levels and generate corresponding control commands. When the operating status characteristic value of S4 is in the normal range, it drives the electronically controlled throttle valve group to perform flow closed-loop regulation according to the control command; when it is in the warning range, it drives the electronically controlled throttle valve group to perform opening correction; when it is in the interlock range, it drives the downhole safety shut-off valve to perform emergency shutdown; and simultaneously uploads the operating data to the surface control terminal to receive and execute remote control commands. S5 monitors the status of the main communication link in real time and automatically switches to the backup communication link to complete data interaction when the main link is abnormal. S6 transmits the adjusted real-time operating data back to the sea surface control terminal to complete single-cycle closed-loop control.

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