A flow acquisition control system and method for a CO2 injection well

Abstract

The present application belongs to the technical field of CO2 gas injection in oil field exploitation, and relates to a flow acquisition control system and method for CO2 injection well, comprising a vortex flowmeter body connected with a Christmas tree through a first pipeline and a second pipeline, the first pipeline and the second pipeline being in communication with each other; a vortex generator arranged in the vortex flowmeter body and detachably connected with the second pipeline; a piezoelectric sensor arranged on the second pipeline; an actuator control valve arranged on the vortex flowmeter body and connected with the connection part of the first pipeline and the second pipeline; a first pressure sensor arranged on the second pipeline and close to the front end of the actuator control valve; and a second pressure sensor arranged on the second pipeline and close to the rear end of the actuator control valve. The present application adjusts the CO2 volume flow through the actuator control valve, realizes the constant of the mass flow in the CO2 injection process, and avoids the occurrence of the gas channeling phenomenon caused by the rapid breakthrough of the injected CO2 along the high permeability layer.

Description

Technical Field

[0001] This invention belongs to the field of CO2 gas injection technology in oilfield development, specifically relating to a flow acquisition and control system and method for CO2 injection wells. Background Technology

[0002] In the oil extraction sector, with the continuous development of oil fields, the decline in reservoir pressure has become one of the key factors restricting high and stable oil production. Reduced reservoir pressure leads to significant degassing of underground crude oil, increasing its viscosity, and consequently causing a significant decrease in well production, even resulting in well shutdowns. This not only leaves a large amount of dead oil underground, causing serious resource waste, but also increases the economic costs and environmental risks of oil field development.

[0003] To effectively compensate for underground deficits resulting from crude oil extraction, increase reservoir pressure, and thus maintain or enhance well production, achieving high and stable oilfield production and a high recovery rate, the industry commonly employs water injection into the formation. However, this traditional method presents several problems in low-permeability reservoirs. First, the initial pressure of the injection well is high, and as the injection process progresses, both the formation and injection pressures rise rapidly, which is particularly detrimental to low-permeability reservoirs. Second, the effects of water injection in production wells are often unsatisfactory, with formation pressure and production declining rapidly, making it difficult to achieve the expected production increase. Finally, even if production wells initially show some production increase, the production index drops significantly over time, and oil production decreases rapidly, further limiting the effectiveness of the water injection method.

[0004] In light of the aforementioned problems, oil companies began exploring new technological approaches to address the challenges of developing low-permeability reservoirs. Against this backdrop, oil companies actively explored and implemented a gas injection process involving the injection of CO2 into wells (i.e., "CO2 flooding"). This process utilizes the solubility, expansion, and viscosity-reducing properties of CO2 to effectively improve the flow properties of crude oil, increase reservoir pressure, and thus enhance well production and recovery rates.

[0005] However, CO2 flooding technology also faces challenges in practical applications. In particular, when the injection volume is not properly controlled, the injected CO2 can rapidly surge along high-permeability layers, leading to gas channeling. This not only reduces CO2 utilization efficiency but may also damage the formation structure. Therefore, intelligently controlling the CO2 injection volume based on changes in formation pressure and temperature to achieve balanced injection is crucial for the successful application of CO2 flooding technology. Summary of the Invention

[0006] The purpose of this invention is to provide a flow acquisition and control system and method for CO2 injection wells.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] In a first aspect, this application provides a flow acquisition and control system for CO2 injection wells, comprising:

[0009] The vortex flow meter body is connected to the wellhead via a first pipe and a second pipe, and the first pipe and the second pipe are interconnected.

[0010] A vortex generator is disposed within the vortex flow meter body and is detachably connected to the second pipe;

[0011] A piezoelectric sensor is installed on the second pipe;

[0012] An actuator control valve is mounted on the vortex flow meter body and connected to the connection between the first pipe and the second pipe.

[0013] A first pressure sensor is installed on the second pipeline and close to the front end of the actuator control valve;

[0014] A second pressure sensor is installed on the second pipeline and near the rear end of the actuator control valve.

[0015] A temperature sensor is disposed inside a cavity on the body of the vortex flowmeter.

[0016] The vortex flow meter head is connected to the piezoelectric sensor, the first pressure sensor, the second pressure sensor, the temperature sensor, and the actuator control valve through a conduit and a cavity. The vortex flow meter head is equipped with a control device.

[0017] Furthermore, the control device includes:

[0018] The MCU is installed on the vortex flow meter head and connected to the actuator control valve;

[0019] A pressure signal processing circuit is connected to the first pressure sensor and the second pressure sensor.

[0020] A temperature signal processing circuit is connected to the temperature sensor;

[0021] A valve position signal processing circuit is connected to the valve position sensor in the actuator control valve;

[0022] A flow signal circuit is connected to the piezoelectric sensor;

[0023] The pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, and flow signal circuit are all connected to the MCU through an AD analog-to-digital converter chip.

[0024] The control panel module is connected to the MCU;

[0025] The control algorithm module is connected to the MCU;

[0026] The remote transmission module is connected to the MCU at one end and to a remote host computer at the other end.

[0027] The system power management circuit is connected to the MCU, pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, flow signal circuit, control panel module, control algorithm module and remote transmission module respectively.

[0028] Furthermore, the temperature signal processing circuit includes:

[0029] The first operational amplifier chip U1A has a constant voltage source connected to its third pin. The second pin of the first operational amplifier chip U1A is connected to its first pin. A first resistor R1, a second resistor R2, and a third resistor R3 are connected in series on the first pin of the first operational amplifier chip U1A. The third resistor R3 is grounded. The first resistor R1, the second resistor R2, and the third resistor R3 divide the voltage output by the first operational amplifier chip U1A to form a voltage divider voltage VYL.

[0030] The first filter capacitor C1 has one end connected to the output voltage of the first operational amplifier chip U1A, and the other end grounded.

[0031] The second operational amplifier chip U1B has its fifth pin connected to the voltage divider VYL, and its sixth and seventh pins are both connected to the temperature sensor.

[0032] The temperature sensor is grounded through a fourth resistor R4, and the first voltage T+ and the second voltage T- across the temperature sensor are connected to the input pin of the AD analog-to-digital converter chip.

[0033] Furthermore, the pressure signal processing circuit includes:

[0034] The third operational amplifier chip U2A has its eleventh pin connected to a constant voltage source, its third pin connected to the voltage divider VYL, its second pin grounded through a first current-limiting resistor R5, its first pin connected to the tenth pin of the first pressure sensor through a fifth resistor R6, its eleventh pin grounded through a first current-limiting resistor R5, its twelfth pin connected to a third voltage NO+, its thirteenth pin connected to a fourth voltage NO-, and its third and fourth voltages NO+ and NO- connected to the input pins of the AD analog-to-digital converter chip.

[0035] The fourth operational amplifier chip U2B has its fifth pin connected to the voltage divider VYL, its sixth pin grounded through the second current-limiting resistor R7, its seventh pin connected to the fourteenth pin of the second pressure sensor through the sixth resistor R8, its fifteenth pin grounded through the second current-limiting resistor R7 and connected to the sixth pin of the fourth operational amplifier chip U2B, its sixteenth pin connected to the fifth voltage WO+, its seventeenth pin connected to the sixth voltage WO-, and its fifth voltage WO+ and sixth voltage WO- connected to the input pin of the AD analog-to-digital converter chip.

[0036] Furthermore, the flow signal circuit includes:

[0037] The fifth operational amplifier chip U3 has its third pin connected to the first output signal Wj+ and the second output signal Wj- of the vortex flowmeter body.

[0038] The sixth operational amplifier chip U4A has its third pin connected to the sixth pin of the fifth operational amplifier chip U3.

[0039] The seventh operational amplifier chip U4B has its sixth pin connected to the first pin of the sixth operational amplifier chip U4A via the fifteenth resistor R17 and the sixteenth resistor R18.

[0040] The eighth operational amplifier chip U5A has its second pin connected to the seventh pin of the seventh operational amplifier chip U4B via the eleventh capacitor C12 and the twenty-second resistor R24.

[0041] Analog switch U6, the first pin of which is connected to the first pin of the eighth operational amplifier chip U5A;

[0042] The ninth operational amplifier chip U7 has its third pin connected to the second pin of the analog switch U6, and its sixth pin connected to the input pin of the AD analog-to-digital converter chip.

[0043] Furthermore, the control panel module includes a control mode selection component, an alarm component, and a flow coefficient modification component;

[0044] The control mode selection component includes constant current mode, constant voltage mode, and opening mode;

[0045] The constant flow mode is used to feed back the measured flow rate value to the MCU, and the MCU adjusts the valve of the actuator control valve according to the flow rate value;

[0046] The constant pressure mode is used by the MCU to adjust the valve of the actuator control valve according to the flow rate value in order to maintain constant pressure;

[0047] The opening mode is used to control the opening degree of the actuator control valve to achieve a preset water injection volume or inlet water pressure.

[0048] The alarm component is used to observe the change in flow rate through the host computer when the vortex flow meter issues an alarm signal.

[0049] The flow coefficient modification component is used to adjust the overall flow rate by modifying the coefficients K and B of the vortex flow meter in the host computer when the flow rate exceeds a preset threshold. Here, K represents the linearity of the flow rate and B represents the degree of deviation from the zero point of the flow rate.

[0050] Furthermore, the vortex flow meter body is provided with a valve core, the valve core is provided with an inclined flow hole, and the flow hole is provided with an I-shaped rotary valve plate adapted to it.

[0051] The vortex generator is a double vortex generator in the shape of a triangular prism and a cylinder.

[0052] Secondly, this application provides a control method for a flow acquisition and control system for a CO2 injection well, comprising the following steps:

[0053] Obtain the pressure, temperature, and CO2 volumetric flow rate of the pipeline above the well to be tested;

[0054] The CO2 density value is obtained based on the pressure and temperature, using a three-dimensional model of temperature-pressure-density and the isobaric coefficient lookup table method.

[0055] The mass flow rate of CO2 is calculated based on the CO2 volumetric flow rate and CO2 density value above the well.

[0056] The mass flow rate of CO2 is compared with the preset target mass flow rate of CO2. If there is a deviation between the mass flow rate of CO2 and the preset target mass flow rate of CO2, the volumetric flow rate of CO2 is adjusted by an adaptive integral separation PID control algorithm to achieve a constant mass flow rate during CO2 injection.

[0057] Furthermore, the steps for constructing the temperature-pressure-density three-dimensional model include:

[0058] Obtain CO2 density data and analyze the calculation model;

[0059] Based on the CO2 density data analysis and calculation model, the function coefficients and intercept coefficients corresponding to different isobars are determined.

[0060] Based on the function coefficients and intercept coefficients corresponding to different isobars, a three-dimensional model of temperature-pressure-density is determined.

[0061] Furthermore, the adjustment of CO2 volumetric flow rate using an adaptive integral separation PID control algorithm includes the following steps:

[0062] Determine the volumetric flow rate of CO2 to be injected based on the mass flow rate of CO2.

[0063] The volumetric flow rate deviation is determined based on the volumetric flow rate of the CO2 to be injected and the current daily CO2 volumetric flow rate.

[0064] The adaptive integral separation PID control algorithm is used to adjust the opening of the actuator control valve according to the volumetric flow rate deviation, thereby regulating the volumetric flow rate of CO2.

[0065] The present invention has the following advantages due to the adoption of the above technical solutions:

[0066] The present invention relates to a flow acquisition and control system and method for CO2 injection wells. During CO2 flooding operations in an oil well, data is measured within the pipeline using a first pressure sensor, a second pressure sensor, and a temperature sensor. This measured data is transmitted via a conduit to a control device within a vortex flowmeter. The control device processes this data, calculates the actual CO2 mass flow rate, and, based on preset parameters and instructions, adjusts the CO2 volumetric flow rate via an actuator-controlled valve. This achieves CO2 volumetric flow rate control, ensuring a constant mass flow rate during CO2 injection and preventing rapid propagation of injected CO2 along high-permeability layers, which could lead to gas channeling. Attached Figure Description

[0067] Figure 1 This is a schematic diagram of the vortex flowmeter body structure in the flow acquisition and control system for CO2 injection wells of the present invention.

[0068] Figure 2 This is a schematic diagram of the vortex flowmeter valve core structure in the flow acquisition and control system for CO2 injection wells of the present invention.

[0069] Figure 3 This is a schematic diagram of the rotary valve plate structure of the vortex flowmeter in the flow acquisition and control system for CO2 injection wells of the present invention.

[0070] Figure 4 This is a structural diagram of the triangular and cylindrical vortex generators in the flow acquisition and control system for CO2 injection wells of the present invention.

[0071] Figure 5 This is a block diagram of the control device in the flow acquisition and control system for CO2 injection wells of the present invention.

[0072] Figure 6 This is a circuit diagram of temperature signal processing in the flow acquisition and control system for CO2 injection wells of the present invention.

[0073] Figure 7 This is a circuit diagram of the pressure signal processing in the flow acquisition and control system for CO2 injection wells of the present invention.

[0074] Figure 8 This is a flow signal circuit diagram in the flow acquisition and control system for CO2 injection wells of the present invention.

[0075] Figure 9 This is a flowchart of the vortex flowmeter acquisition and control operation of the flow acquisition and control system for CO2 injection wells according to the present invention.

[0076] Figure 10 This is an anti-interference circuit diagram for the flow acquisition and control system of CO2 injection wells according to the present invention.

[0077] Figure 11 This is a flowchart of the flow acquisition and control method for CO2 injection wells according to the present invention.

[0078] The attached figures are labeled as follows: 1-Vortex flowmeter body, 101-First pipe, 102-Second pipe, 103-Cavity, 104-Valve core, 105-Flow hole, 106-Rotating valve plate, 2-Vortex generator, 3-Piezoelectric sensor, 4-First pressure sensor, 5-Temperature sensor, 6-Second pressure sensor, 7-Drive shaft, 8-Conduit, 9-Vortex flowmeter head, 10-Actuator control valve, 11-Coupling, 12-Flange, 13-Anti-rotation hole. Detailed Implementation

[0079] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so as to better understand the purpose, features and advantages of the present invention. It should be understood that the embodiments shown in the drawings are not intended to limit the scope of the present invention, but are only for illustrating the essential spirit of the technical solution of the present invention.

[0080] This invention provides a flow acquisition and control system for CO2 injection wells, specifically as follows: Figure 1 As shown, the system includes a vortex flowmeter body 1, a vortex generator 2, a piezoelectric sensor 3, a first pressure sensor 4, a second pressure sensor 6, a temperature sensor 5, an actuator control valve 10, and a vortex flowmeter head 9. The vortex flowmeter body 1 is connected to the wellhead via a first pipe 101 and a second pipe 102, with the first pipe 101 and the second pipe 102 interconnected. The vortex generator 2 is located inside the vortex flowmeter body 1 and is detachably connected to the second pipe 102. The piezoelectric sensor 3 is located on the second pipe 102. The actuator control valve 10 is located on the vortex flowmeter body 1 and is connected to the first pipe... The connection between pipe 101 and pipe 102 is made; the first pressure sensor 4 is installed on pipe 102 and close to the front end of actuator control valve 10; the second pressure sensor 6 is installed on pipe 102 and close to the rear end of actuator control valve 10; the temperature sensor 5 is installed in cavity 103 on the body of vortex flowmeter 1; the vortex flowmeter head 9 is connected to piezoelectric sensor 3, first pressure sensor 4, second pressure sensor 6, temperature sensor 5 and actuator control valve 10 through conduit 8 and cavity 103, and a control device is installed on the vortex flowmeter head 9.

[0081] In this embodiment, when the oil well is undergoing CO2 flooding operations, CO2 liquid enters the vortex flowmeter system (i.e., the vortex flowmeter body 1) through the wellhead, specifically through the first pipe 101 and the second pipe 102. The second pipe 102 is the primary measurement channel. As the CO2 liquid passes through the vortex generator 2, the vibration of these vortices causes deformation of the piezoelectric sensor 3, generating an electrical signal. The piezoelectric sensor 3 converts this mechanical vibration into an electrical signal output. The first pressure sensor 4 measures the pressure at the valve's upstream end, and the second pressure sensor 6 measures the pressure at the valve's downstream end to monitor the CO2 liquid state. The temperature sensor 5 measures the temperature within the vortex flowmeter body, as temperature affects flow measurement accuracy. The data collected by the piezoelectric sensor 3, the first pressure sensor 4, the second pressure sensor 6, and the temperature sensor 5 are transmitted through the conduit 8 and cavity 103 to the control device within the vortex flowmeter head 9. The control device processes this data, calculates the actual CO2 mass flow rate, and adjusts the CO2 volumetric flow rate through the actuator control valve 10 according to preset parameters or external commands. When the CO2 volumetric flow rate deviates from the set value, the control device sends a signal to the actuator control valve 10 to adjust the valve opening, thereby changing the fluid flow rate through the vortex flow meter body to achieve the purpose of CO2 volumetric flow rate control, so as to keep the mass flow rate constant during CO2 injection and avoid the rapid advance along the high permeability layer during CO2 injection, which would lead to gas channeling.

[0082] Furthermore, the vortex flow meter body is connected to the first pipe and the second pipe respectively through two flanges 12, and a double-layer sealing ring is added at the connection to meet the sealing performance under high pressure conditions; the piezoelectric sensor 3 is fixed to the surface of the second pipe 102 by screws; the first pressure sensor 4 and the second pressure sensor 6 are fixedly assembled on the second pipe 102 by threads; the temperature sensor 5 is inserted into the cavity 103; the actuator control valve 10 is connected to the vortex flow meter body by screws and nuts.

[0083] In one embodiment, such as Figure 2 The diagram shows the valve core structure of the vortex flow meter. The valve core 104 is installed inside the vortex flow meter body 1, and the valve core 104 is provided with an inclined flow hole 105.

[0084] As a preferred option, the flow orifice 105 is designed with an inclined shape to reduce pressure loss and improve measurement accuracy.

[0085] like Figure 3 The diagram shows the structure of the rotary valve plate 106, which is adapted to the flow passage 105.

[0086] As a preferred option, the rotary valve plate 106 adopts an "I"-shaped structure, primarily used to fit the flow passage 105. The rotary valve plate is made of high-pressure resistant and high-temperature resistant 9Cr18 stainless steel. By using wear-resistant materials and improving the structural design of the valve core flow passage and the rotary valve plate, the rotary valve plate 106 enhances the wear resistance of the valve core, extends its service life, and improves the reliability of the measuring range. Furthermore, through a control device, precise control of the valve core is achieved, automatically adjusting the valve core state according to fluid characteristics and flow requirements, thereby improving the adaptability of the measuring range and the measurement accuracy.

[0087] In this embodiment, by optimizing the valve core design, the range of the vortex flow meter can be effectively increased to meet the flow measurement needs of different application scenarios. This overcomes the problems of limited adjustment range, inaccurate measurement of small flow rates, and large pipeline interference in vortex flow meters, making flow regulation more precise.

[0088] Furthermore, the actuator control valve 10 includes an actuator head, a coupling 11, and a drive shaft 7. The actuator head is located on the top of the vortex flowmeter body. One end of the coupling 11 is connected to the actuator head, and the other end is connected to the drive shaft 7. The drive shaft 7 extends into the vortex flowmeter body and is fitted with the anti-rotation hole 13 inside the valve core, and is connected to the rotary valve plate 106. The anti-rotation hole is fitted with one end of the drive shaft. This fitting method restricts the circumferential rotation of the drive shaft, allowing the drive shaft to move along the axial direction, thereby ensuring the stability and accuracy of the valve core during the opening and closing process.

[0089] When the actuator controls the valve, an external control signal is applied to the actuator head, which converts the signal into a mechanical action. This mechanical action is transmitted to the drive shaft 7 via the coupling 11. The drive shaft 7 further transmits the received power or signal to the rotary valve disc 106. The rotary valve disc 106 performs corresponding actions according to the power or signal transmitted by the drive shaft, thereby achieving the blocking or opening operation of the valve.

[0090] In one embodiment, specifically as follows Figure 4 As shown, the vortex generator 2 adopts a double vortex generator with triangular prism and cylindrical shape.

[0091] Furthermore, the vortex generator is fixed to the vortex flowmeter body using appropriate bolts, nuts, and gaskets. The shape and spacing of the vortex generators can be flexibly designed according to different operating conditions. The vortex generator is detachably connected to the second pipe, allowing for the measurement of media in pipes with different cross-sectional areas to adapt to various operating conditions and ensure high-precision, high-reliability flow measurement. For pipes with different cross-sectional areas, the vortex flowmeter adapts to different pipe diameters by adjusting the size and shape of the vortex generator. Larger diameter pipes can use larger vortex generators, while smaller diameter pipes require smaller vortex generators. In comparing the selection of vortex generator shapes, cylindrical generators have a higher Strouhal number and lower pressure loss, exhibiting good performance at low flow rates; triangular prism generators have higher vortex strength, stronger signal-to-noise ratio, and stronger stability. Therefore, this embodiment combines the advantages of both to design a dual vortex generator structure that combines a triangular prism generator and a cylindrical generator. This structure has the advantages of both, making the signal output of the vortex flowmeter more stable and accurate. In addition, the dual vortex generator has a low signal-to-noise ratio, which comprehensively improves the accuracy and stability of the flow measurement.

[0092] In one embodiment, such as Figure 5 As shown, the control device includes an MCU (microcontroller unit), a pressure signal processing circuit, a temperature signal processing circuit, a valve position signal processing circuit, and a flow signal circuit. The MCU is mounted on the vortex flow meter head 9 and connected to the actuator control valve 10. The pressure signal processing circuit is connected to the first pressure sensor 4 and the second pressure sensor 6. The temperature signal processing circuit is connected to the temperature sensor 5. The valve position signal processing circuit is connected to the valve position sensor in the actuator control valve 10. The flow signal circuit is connected to the piezoelectric sensor 3. The pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, and flow signal circuit are all connected to the MCU via an AD converter chip. The SPI pin of the MCU is connected to the output of the AD converter chip to acquire data such as pressure, temperature, and CO2 volumetric flow rate. The control panel module is connected to the MCU; the control algorithm module is connected to the MCU; the remote transmission module is connected to the MCU on one end and to a remote host computer on the other end; the system power management circuit is connected to the MCU, pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, flow signal circuit, control panel module, control algorithm module, and remote transmission module.

[0093] In this invention, specifically as follows: Figure 1-5As shown, the system first uses a first pressure sensor 4, a second pressure sensor 6, a temperature sensor 5, and a vortex flow meter to collect pressure, temperature, valve opening, and CO2 volumetric flow rate data from the pipeline above the well. After the system is powered on, the MCU initializes. Once initialization is complete, the MCU begins collecting data such as pressure, temperature, valve opening, and CO2 volumetric flow rate, storing this data in an external Flash chip for local storage. After storing the data, the MCU waits for the next data acquisition. The MCU is connected to a storage management circuit via an SPI digital signal interface to store the collected pressure, temperature, and CO2 volumetric flow rate data in real time. This stored data can be replayed. After the MCU processes the collected pressure, temperature, and CO2 volumetric flow rate data, the data is transmitted to the client data monitoring center via a remote host computer and a remote transmission module.

[0094] In one embodiment, such as Figure 6 As shown, the temperature signal processing circuit includes a first operational amplifier chip U1A, a first filter capacitor C1, and a second operational amplifier chip U1B. A constant voltage source is connected to the third pin of the first operational amplifier chip U1A. The second pin of the first operational amplifier chip U1A is connected to the first pin of the first operational amplifier chip U1A. A first resistor R1, a second resistor R2, and a third resistor R3 are connected in series to the first pin of the first operational amplifier chip U1A. The third resistor R3 is grounded. The first resistor R1, the second resistor R2, and the third resistor R3 divide the voltage output by the first operational amplifier chip U1A to form a voltage divider voltage VYL. One end of the first filter capacitor C1 is connected to the output voltage of the first operational amplifier chip U1A, and the other end is grounded. The fifth pin of the second operational amplifier chip U1B is connected to the voltage divider voltage VYL. The sixth and seventh pins of the second operational amplifier chip U1B are both connected to the temperature sensor 5 (i.e., temperature sensor JO). The temperature sensor 5 is grounded through a fourth resistor R4. The first voltage T+ and the second voltage T- across the temperature sensor 5 are connected to the input pin of the AD analog-to-digital converter chip.

[0095] In one embodiment, such as Figure 7As shown, the pressure signal processing circuit includes a third operational amplifier chip U2A and a fourth operational amplifier chip U2B. The eleventh pin of the third operational amplifier chip U2A is connected to a constant voltage source, the third pin of the third operational amplifier chip U2A is connected to a voltage divider voltage VYL, the second pin of the third operational amplifier chip U2A is grounded through a first current-limiting resistor R5, the first pin of the third operational amplifier chip U2A is connected to the tenth pin of the first pressure sensor 4 (i.e., the first pressure sensor P1) through a fifth resistor R6, the eleventh pin of the first pressure sensor 4 is grounded through the first current-limiting resistor R5 and is connected to the second pin of the third operational amplifier chip U2A, the twelfth pin of the first pressure sensor 4 is connected to a third voltage NO+, the thirteenth pin of the first pressure sensor 4 is connected to a fourth voltage NO-, and the third voltage NO+ and the fourth voltage NO- are connected to the input pins of the AD analog-to-digital converter chip.

[0096] The fifth pin of the fourth operational amplifier chip U2B is connected to the voltage divider voltage VYL. The sixth pin of the fourth operational amplifier chip U2B is grounded through the second current-limiting resistor R7. The seventh pin of the fourth operational amplifier chip U2B is connected to the fourteenth pin of the second pressure sensor 6 (i.e., the second pressure sensor P2) through the sixth resistor R8. The fifteenth pin of the second pressure sensor 6 is grounded through the second current-limiting resistor R7 and is connected to the sixth pin of the fourth operational amplifier chip U2B. The sixteenth pin of the second pressure sensor 6 is connected to the fifth voltage WO+, and the seventeenth pin of the second pressure sensor 6 is connected to the sixth voltage WO-. The fifth voltage WO+ and the sixth voltage WO- are connected to the input pins of the AD analog-to-digital converter chip.

[0097] In one embodiment, such as Figure 8As shown, the flow signal circuit includes a fifth operational amplifier chip U3, a sixth operational amplifier chip U4A, a seventh operational amplifier chip U4B, an eighth operational amplifier chip U5A, an analog switch U6, and a ninth operational amplifier chip U7. The third pin of the fifth operational amplifier chip U3 is connected to the first output signal Wj+ and the second output signal Wj- of the vortex flowmeter body through a first capacitor C2 and a second capacitor C3. The third pin of the fifth operational amplifier chip U3 is also connected in series with a seventh resistor R9 and an eighth resistor R10, and in parallel with a 3.3V resistor connected through a ninth resistor R11, a tenth resistor R12, and... The voltage signal after voltage division by the third capacitor C4; the second pin of the feedback terminal of the fifth operational amplifier chip U3 is grounded through the eleventh resistor R13 and the fourth capacitor C5, and connected to the sixth pin of the fifth operational amplifier chip U3 through the twelfth resistor R14 and the fifth capacitor C6. The sixth pin of the fifth operational amplifier chip U3 is connected in series with the thirty-sixth resistor R40 and the thirty-seventh resistor R41. The thirty-eighth resistor R42 and the sixteenth capacitor C18 are connected between the thirty-sixth resistor R40 and the thirty-seventh resistor R41. The thirty-eighth resistor R42 and the sixteenth capacitor C18 are connected in parallel. The seventh and eighth pins of the fifth operational amplifier chip U3 are connected to a 3.3V voltage, and the fourth pin of the fifth operational amplifier chip U3 is grounded. The feedback terminal of the fifth operational amplifier chip U3 adjusts the signal through the resistance values ​​of the eleventh resistor R13 and the twelfth resistor R14. Due to the presence of the fourth capacitor C5 and the fifth capacitor C6, the fifth operational amplifier chip U3 only amplifies the AC signal, while the DC signal remains unchanged. That is, the voltage signal at the sixth pin of the fifth operational amplifier chip U3 is the superposition of the voltage divider signal and the amplified signal between Wj+ and Wj-.

[0098] The third pin of the sixth op-amp chip U4A is connected to the sixth pin of the fifth op-amp chip U3. The second pin of the sixth op-amp chip U4A is grounded through the thirteenth resistor R15 and the sixth capacitor C7. It is connected to the first pin of the sixth op-amp chip U4A through the fourteenth resistor R16 and the seventh capacitor C8. The eleventh pin of the sixth op-amp chip U4A is grounded, and the fourth pin of the sixth op-amp chip U4A is connected to a 3.3V voltage.

[0099] The sixth pin of the seventh operational amplifier chip U4B is filtered by a low-pass filter circuit composed of the fifteenth resistor R17 and the eighth capacitor C9, and then connected to the first pin of the sixth operational amplifier chip U4A through the sixteenth resistor R18. The sixth pin of the feedback terminal of the seventh operational amplifier chip U4B is also connected in parallel with the seventeenth resistor R19 and the ninth capacitor C10. The seventeenth resistor R19 is connected to the tenth capacitor C11. The tenth capacitor C11 is connected in series with two anti-parallel diodes, the first diode D1 and the second diode D2, and the eighteenth resistor R20. The eighteenth resistor R20 is grounded through the eighth capacitor C9. The two anti-parallel diodes, the first diode D1 and the second diode D2, mainly serve to limit voltage and protect against reverse voltage, preventing damage to the operational amplifier due to reverse power supply polarity or external interference. Pin 5 of the seventh op-amp chip U4B is connected to resistors R21 (nineteenth), R22 (twentieth), and R23 (twenty-first). Resistor R22 is grounded, and R23 is connected to 3.3V. Pin 7 of the seventh op-amp chip U4B is connected to pin 2 of the eighth op-amp chip U5A via capacitor C12 (eleventh) and resistor R24 ​​(twenty-second). Pin 7 of the seventh op-amp chip U4B converts the sinusoidal signal into a signal similar to a square wave, which is then filtered by capacitor C12 (eleventh).

[0100] The second pin of the eighth op-amp chip U5A is connected to the seventh pin of the seventh op-amp chip U4B. The third pin of the eighth op-amp chip U5A is connected to resistors R25 (twenty-third), R26 (twenty-fourth), and R27 (twenty-fifth). Resistor R26 is grounded, and resistor R27 is connected to a 3.3V voltage. The third pin of the eighth op-amp chip U5A is connected to its first pin via resistor R28 (twenty-sixth). The 3.3V signal input to the non-inverting input of the eighth op-amp chip U5A is divided by resistors R26 and R27, forming an inverting hysteresis comparator circuit that inverts the rectangular wave signal.

[0101] The first pin of analog switch U6 is connected to the first pin of the eighth operational amplifier chip U5A, the second pin of analog switch U6 is connected to the ninth operational amplifier chip U7, the third pin of analog switch U6 is grounded, and the fifth pin of analog switch U6 is connected to a 5V voltage.

[0102] The third pin of the ninth operational amplifier chip U7 is connected to the second pin of the analog switch U6 via bypass capacitor C13 and pull-down resistor R29. The second pin of the ninth operational amplifier chip U7 is connected to the sixth pin of the ninth operational amplifier chip U7 via resistor R30 (the twenty-seventh resistor). The ninth operational amplifier chip U7 and resistor R30 (the twenty-seventh resistor) form a voltage follower circuit. The sixth pin of the ninth operational amplifier chip U7 is connected to the input pin of the AD converter chip, and the flow rate value is obtained through software algorithm processing. The sixth pin of the ninth operational amplifier chip U7 is grounded via resistor R31 (the twenty-eighth resistor). The fourth pin of the ninth operational amplifier chip U7 is grounded. One end of the seventh pin of the ninth operational amplifier chip U7 is connected to 8V, and the other end is grounded via capacitor C14 (the twelfth capacitor).

[0103] The first pin of the eighth operational amplifier chip U5A is electrically connected to the first pin of the analog switch U6. After passing through the analog switch U6, the output signal is a square wave with a processed frequency. After passing through the pull-down resistor R29 and the bypass capacitor C13, the signal enters the third pin of the ninth operational amplifier chip U7.

[0104] In one embodiment, the control panel module includes a control mode selection component, an alarm component, and a flow coefficient modification component. The control mode selection component includes a constant flow mode, a constant pressure mode, and an opening mode. In constant flow mode, the measured flow rate is fed back to the MCU, which adjusts the actuator control valve based on the flow rate to achieve constant flow. In constant pressure mode, the MCU adjusts the actuator control valve based on the flow rate to maintain constant pressure. Although the vortex flow meter measures flow rate, there is a relationship between flow rate and pressure. While the vortex flow meter cannot directly control pressure, it indirectly participates in the pressure control process by measuring flow rate. When constant pressure needs to be maintained, the MCU adjusts the pump speed or valve opening based on the flow rate measured by the vortex flow meter to maintain pressure stability. The opening mode is used to control the opening degree of the actuator control valve to achieve the preset water injection volume or inlet water pressure; the alarm component is used to observe the flow change through the host computer when the vortex flow meter issues an alarm signal; the flow coefficient modification component is used to adjust the coefficients K and B of the vortex flow meter through the remote host computer when the flow value exceeds the preset threshold, so as to adjust the overall flow. Here, K represents the linearity of the flow, and B represents the degree of deviation from the zero point of the flow.

[0105] In this embodiment, as Figure 9As shown, pressure, temperature, CO2 volumetric flow rate, and valve opening are collected from the pipeline in the well to be logged using pressure sensors, temperature sensors, and a vortex flowmeter. The system observes whether the vortex flowmeter alarms. When no alarm occurs, the fluctuation of CO2 volumetric flow rate is monitored via a display screen or remote computer to see if it exceeds 1 cubic meter per day. If it does, the damping coefficient of the vortex flowmeter is adjusted on the remote computer to stabilize the measured flow rate within 1 cubic meter per day. If it does not exceed this limit, the deviation between the measured instantaneous flow rate and the actual CO2 volumetric flow rate is checked for exceeding θ (this can be set according to actual needs). If the deviation exceeds θ, the coefficients K and B of the vortex flowmeter are adjusted on the remote computer to regulate the overall flow rate. When the deviation does not exceed θ, constant flow mode, constant pressure mode, and opening mode are selected according to the actual operating conditions to maintain a stable flow rate. When temperature and pressure change, the CO2 density is calculated based on a three-dimensional temperature-pressure-density model (which can be simply referred to as the model). The CO2 volumetric flow rate is adjusted in real time through the control algorithm module to achieve balanced CO2 injection.

[0106] Furthermore, the signal processing of the vortex flowmeter employs tracking filters and adaptive filters based on digital technology that adapt to the characteristics of signal and noise changes. The spectral characteristics of the signal and noise are analyzed using spectral analysis to suppress noise and extract useful signals.

[0107] Furthermore, the vortex flow meter employs an anti-interference circuit design. Figure 10 This paper presents a schematic diagram for an anti-interference processing circuit for electrical signals. By processing electrical signals, the circuit can resist external interference and improve the accuracy of measurement results.

[0108] like Figure 10 As shown, the anti-interference circuit design includes the tenth operational amplifier chip U8B, the eleventh operational amplifier chip U8A, and the opto-isolator circuit U10. The fifth pin of the tenth operational amplifier chip U8B is grounded through the twenty-ninth resistor R32, and the sixth pin is connected to the seventh pin of the tenth operational amplifier chip U8B through the thirtieth resistor R33 and the thirteenth capacitor C15 in parallel. The sixth pin of the tenth operational amplifier chip U8B is also connected to the thirty-first resistor R34. The seventh pin of the tenth operational amplifier chip U8B is connected to the input terminal of the opto-isolator circuit U10.

[0109] The third pin of the eleventh operational amplifier chip U8A is connected to the output of the opto-isolator circuit U10 through the thirty-second resistor R35 and the fourteenth capacitor C16; the fourteenth capacitor C16 is grounded. The second pin of the eleventh operational amplifier chip U8A is connected to the first pin of the eleventh operational amplifier chip U8A through the thirty-third resistor R36. The first pin of the eleventh operational amplifier chip U8A is connected to the input pin of the AD converter chip after a voltage divider formed by the thirty-fourth resistor R37 and the thirty-fifth resistor R38; one end of the thirty-fifth resistor R38 is grounded, and the other end is connected in parallel with the fifteenth capacitor C17. The fourth pin of the eleventh operational amplifier chip U8A is grounded. The eighth pin of the eleventh operational amplifier chip U8A is connected to a voltage. The signal passes through the non-inverting amplifier circuit composed of the tenth operational amplifier chip U8B, resulting in high input impedance, large voltage gain, good stability, and resistance to self-oscillation. The signal then enters the opto-isolator circuit U10 from the seventh pin of the tenth operational amplifier chip U8B, providing excellent electrical isolation, unidirectional signal transmission, strong anti-interference capability, and fast response speed. From the output of the opto-isolator circuit U10, the signal enters the low-pass filter circuit composed of the thirty-second resistor R35 and the fourteenth capacitor C16, effectively removing high-frequency noise, retaining low-frequency components, suppressing noise, reducing errors, and amplifying the signal under specific conditions. It then enters the voltage follower circuit composed of the eleventh operational amplifier chip U8A, resulting in high common-mode rejection ratio, wide bandwidth, simplicity, stability, and strong anti-interference capability. Finally, the signal output from the first pin of the eleventh operational amplifier chip U8A is divided by the thirty-fourth resistor R37 and the thirty-fifth resistor R38 before entering the AD converter chip for further processing.

[0110] This invention also provides a control method for a flow acquisition and control device for CO2 injection wells, specifically as follows: Figure 11 As shown, it includes the following steps:

[0111] Step 1: Obtain the pressure, temperature, and CO2 volumetric flow rate of the pipeline above the well to be tested;

[0112] Throughout the CO2 injection process, the pressure, temperature, and CO2 volumetric flow rate in the pipeline above the well need to be monitored in real time. Changes in the pressure and temperature of the pipeline above the well will cause changes in the CO2 density. Based on the principle of CO2 mass conservation, the CO2 mass flow rate needs to be accurately calculated.

[0113] Step 2: Based on pressure and temperature, obtain the CO2 density value using a three-dimensional temperature-pressure-density model and an isobaric coefficient lookup table method;

[0114] The steps for constructing the three-dimensional model of temperature-pressure-density include:

[0115] Step 2.1: Obtain CO2 density data and analyze the calculation model;

[0116] Step 2.2: Based on the CO2 density data analysis and calculation model, determine the function coefficients and intercept coefficients corresponding to different isobars;

[0117] Step 2.3: Determine the three-dimensional model of temperature-pressure-density based on the function coefficients and intercept coefficients corresponding to different isobars.

[0118] This invention establishes a three-dimensional temperature-pressure-density model and uses the isobaric coefficient lookup table method to obtain the density value of CO2. Based on engineering experience, a CO2 density data analysis and calculation model is provided. Through model analysis, the function coefficients and intercept coefficients of different isobars are obtained. Since the function coefficients and intercept coefficients are nonlinear, a two-dimensional data table Factor[a][b] corresponding to the function coefficients and intercept coefficients of different isobars is established. When using this model, the corresponding function coefficient 'a' is obtained by looking up the two-dimensional data table using the measured pressure value. i and intercept coefficient b i This allows us to calculate the CO2 density value at the current pressure and temperature. The formula for calculating the CO2 density value is: ρ = T * a i +b i Where T is the temperature. The CO2 density value at the current pressure and temperature is calculated through the model. The CO2 mass flow rate is obtained based on the CO2 volumetric flow rate at the wellhead. To maintain a constant CO2 mass flow rate, the CO2 volumetric flow rate is adjusted according to the change in CO2 density to ensure balanced CO2 injection.

[0119] Step 3: Calculate the mass flow rate of CO2 based on the CO2 volumetric flow rate and CO2 density value at the well site;

[0120] Step 4: Compare the CO2 mass flow rate with the preset CO2 target mass flow rate. If there is a deviation between the CO2 mass flow rate and the preset CO2 target mass flow rate, adjust the CO2 volume flow rate through an adaptive integral separation PID control algorithm to achieve a constant mass flow rate during CO2 injection.

[0121] Specifically, adjusting the volumetric flow rate of CO2 using an adaptive integral-separated PID control algorithm includes the following steps:

[0122] Step 4.1: Determine the volumetric flow rate of the CO2 to be injected based on the mass flow rate of the CO2;

[0123] Since the pressure inside the well remains constant, the CO2 mass flow rate injected into the well must also remain constant. The CO2 density at this point is multiplied by the CO2 volumetric flow rate to obtain the CO2 mass flow rate, which is then compared with the target CO2 mass flow rate required from the well.

[0124] Step 4.2: Determine the volumetric flow rate deviation based on the volumetric flow rate of the CO2 to be injected and the current daily CO2 volumetric flow rate;

[0125] Step 4.3: Using the adaptive integral separation PID control algorithm, adjust the valve opening of the actuator control valve according to the volumetric flow rate deviation to regulate the volumetric flow rate of CO2.

[0126] Furthermore, let the mass flow rate of CO2 to be injected be m, the volumetric flow rate of CO2 to be injected be V0 = m / ρ, and the current daily volumetric flow rate of CO2 injection be Vi. Then, the volumetric flow rate deviation is ε = Vi - V0. Using this deviation, an adaptive integral-separated PID control algorithm is used to control the opening of the actuator control valve based on the CO2 volumetric flow rate deviation, controlling the flow rate to V0. When the flow rate is constant, the mass flow rate of CO2 is obtained by multiplying the volumetric flow rate and density value of CO2 at this time, keeping the deviation from the set value within the allowable range.

[0127] This invention discloses a flow acquisition and control method for CO2 injection wells. During the injection of CO2 into the well, a vortex flow meter measures the pressure, temperature, and CO2 volumetric flow rate of the pipeline above the well. Based on the pressure and temperature, the CO2 density value is obtained using a three-dimensional model of temperature-pressure-density and a table lookup method of isobaric coefficient. The CO2 mass flow rate can be calculated from the density value, ensuring that the CO2 mass flow rate remains constant, thereby achieving balanced CO2 injection.

[0128] This invention discloses a flow acquisition and control system for CO2 injection wells. A remote transmission module integrated within a vortex flowmeter transmits data such as pressure, temperature, CO2 volumetric flow rate, and valve opening collected by a first pressure sensor, a second pressure sensor, a temperature sensor, the vortex flowmeter, and a valve position sensor to a remote host computer. The host computer displays the data in real time and can remotely observe changes in various parameters of the well, thereby determining the CO2 injection volume and well conditions. The remote host computer, through a control device, performs data acquisition, remote data transmission, and data processing, controlling the valve opening to adjust the flow rate, ensuring accurate CO2 injection and preventing gas leakage.

Claims

1. A flow acquisition and control system for CO2 injection wells, characterized in that, include: The vortex flow meter body (1) is connected to the tree of oil production through a first pipe (101) and a second pipe (102), and the first pipe (101) and the second pipe (102) are interconnected. A vortex generator (2) is disposed inside the vortex flow meter body (1) and is detachably connected to the second pipe (102); A piezoelectric sensor (3) is disposed on the second pipe (102); An actuator control valve (10) is mounted on the vortex flow meter body (1) and connected to the connection between the first pipe (101) and the second pipe (102); The first pressure sensor (4) is installed on the second pipeline (102) and close to the front end of the actuator control valve (10); The second pressure sensor (6) is installed on the second pipeline (102) and close to the rear end of the actuator control valve (10); A temperature sensor (5) is disposed in a cavity (103) on the vortex flowmeter body (1); The vortex flow meter head (9) is connected to the piezoelectric sensor (3), the first pressure sensor (4), the second pressure sensor (6), the temperature sensor (5) and the actuator control valve (10) through the conduit (8) and the cavity (103). The vortex flow meter head (9) is equipped with a control device. The control device calculates the mass flow rate of CO2 based on the data collected by the piezoelectric sensor (3), the first pressure sensor (4), the second pressure sensor (6) and the temperature sensor (5), and adjusts the volume flow rate of CO2 through the actuator control valve (10).

2. The flow acquisition and control system for CO2 injection wells according to claim 1, characterized in that, The control device includes: The MCU is installed on the vortex flow meter head (9) and connected to the actuator control valve (10); The pressure signal processing circuit is connected to the first pressure sensor (4) and the second pressure sensor (6); A temperature signal processing circuit is connected to the temperature sensor (5); The valve position signal processing circuit is connected to the valve position sensor in the actuator control valve (10); The flow signal circuit is connected to the piezoelectric sensor (3); The pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, and flow signal circuit are all connected to the MCU through an AD analog-to-digital converter chip. The control panel module is connected to the MCU; The control algorithm module is connected to the MCU; The remote transmission module is connected to the MCU at one end and to a remote host computer at the other end. The system power management circuit is connected to the MCU, pressure signal processing circuit, temperature signal processing circuit, valve position signal processing circuit, flow signal circuit, control panel module, control algorithm module and remote transmission module respectively.

3. The flow acquisition and control system for CO2 injection wells according to claim 2, characterized in that, The temperature signal processing circuit includes: The first operational amplifier chip U1A has a constant voltage source connected to its third pin. The second pin of the first operational amplifier chip U1A is connected to its first pin. A first resistor R1, a second resistor R2, and a third resistor R3 are connected in series on the first pin of the first operational amplifier chip U1A. The third resistor R3 is grounded. The first resistor R1, the second resistor R2, and the third resistor R3 divide the voltage output by the first operational amplifier chip U1A to form a voltage divider voltage VYL. The first filter capacitor C1 has one end connected to the output voltage of the first operational amplifier chip U1A, and the other end grounded. The second operational amplifier chip U1B has its fifth pin connected to the voltage divider VYL, and its sixth and seventh pins are both connected to the temperature sensor (5). The temperature sensor (5) is grounded through the fourth resistor R4, and the first voltage T+ and the second voltage T- at both ends of the temperature sensor (5) are connected to the input pin of the AD analog-to-digital converter chip.

4. The flow acquisition and control system for CO2 injection wells according to claim 3, characterized in that: The pressure signal processing circuit includes: The third operational amplifier chip U2A has its eleventh pin connected to a constant voltage source, its third pin connected to a voltage divider VYL, its second pin grounded through a first current-limiting resistor R5, its first pin connected to the tenth pin of the first pressure sensor (4) through a fifth resistor R6, its eleventh pin grounded through a first current-limiting resistor R5, its twelfth pin connected to a third voltage NO+, its thirteenth pin connected to a fourth voltage NO-, and its third and fourth voltages NO+ and NO- connected to the input pins of the AD analog-to-digital converter chip. The fourth operational amplifier chip U2B has its fifth pin connected to the voltage divider VYL, its sixth pin grounded through the second current-limiting resistor R7, its seventh pin connected to the fourteenth pin of the second pressure sensor (6) through the sixth resistor R8, its fifteenth pin grounded through the second current-limiting resistor R7 and connected to the sixth pin of the fourth operational amplifier chip U2B, its sixteenth pin connected to the fifth voltage WO+, its seventeenth pin connected to the sixth voltage WO-, and its fifth voltage WO+ and sixth voltage WO- connected to the input pin of the AD analog-to-digital converter chip.

5. The flow acquisition and control system for CO2 injection wells according to claim 3, characterized in that: The flow signal circuit includes: The fifth operational amplifier chip U3 has its third pin connected to the first output signal Wj+ and the second output signal Wj- of the vortex flowmeter body. The sixth operational amplifier chip U4A has its third pin connected to the sixth pin of the fifth operational amplifier chip U3. The seventh operational amplifier chip U4B has its sixth pin connected to the first pin of the sixth operational amplifier chip U4A via the fifteenth resistor R17 and the sixteenth resistor R18. The eighth operational amplifier chip U5A has its second pin connected to the seventh pin of the seventh operational amplifier chip U4B via the eleventh capacitor C12 and the twenty-second resistor R24. Analog switch U6, the first pin of which is connected to the first pin of the eighth operational amplifier chip U5A; The ninth operational amplifier chip U7 has its third pin connected to the second pin of the analog switch U6, and its sixth pin connected to the input pin of the AD analog-to-digital converter chip.

6. The flow acquisition and control system for CO2 injection wells according to claim 5, characterized in that: The control panel module includes a control mode selection component, an alarm component, and a flow coefficient modification component; The control mode selection component includes constant current mode, constant voltage mode, and opening mode; The constant flow mode is used to feed back the measured flow rate value to the MCU, and the MCU adjusts the valve of the actuator control valve according to the flow rate value; The constant pressure mode is used by the MCU to adjust the valve of the actuator control valve according to the flow rate value in order to maintain constant pressure; The opening mode is used to control the opening degree of the actuator control valve to achieve a preset water injection volume or inlet water pressure. The alarm component is used to observe the change in flow rate through the host computer when the vortex flow meter issues an alarm signal. The flow coefficient modification component is used to adjust the overall flow rate by modifying the coefficients K and B of the vortex flow meter in the host computer when the flow rate exceeds a preset threshold. Here, K represents the linearity of the flow rate and B represents the degree of deviation from the zero point of the flow rate.

7. The flow acquisition and control system for CO2 injection wells according to claim 6, characterized in that: The vortex flowmeter body (1) is provided with a valve core (104), and the valve core (104) is provided with an inclined flow hole (105), and the flow hole (105) is provided with an I-shaped rotary valve plate (106) adapted to it. The vortex generator (2) adopts a double vortex generator in the shape of a triangular prism and a cylinder.

8. A control method employing the flow acquisition and control system for a CO2 injection well as described in any one of claims 1-7, characterized in that, Includes the following steps: Obtain the pressure, temperature, and CO2 volumetric flow rate of the pipeline above the well to be tested; The CO2 density value is obtained based on the pressure and temperature, using a three-dimensional model of temperature-pressure-density and the isobaric coefficient lookup table method. The mass flow rate of CO2 is calculated based on the CO2 volumetric flow rate and CO2 density value above the well. The mass flow rate of CO2 is compared with the preset target mass flow rate of CO2. If there is a deviation between the mass flow rate of CO2 and the preset target mass flow rate of CO2, the volumetric flow rate of CO2 is adjusted by an adaptive integral separation PID control algorithm to achieve a constant mass flow rate during CO2 injection.

9. The control method according to claim 8, characterized in that, The steps for constructing the temperature-pressure-density three-dimensional model include: Obtain CO2 density data and analyze the calculation model; Based on the CO2 density data analysis and calculation model, the function coefficients and intercept coefficients corresponding to different isobars are determined. Based on the function coefficients and intercept coefficients corresponding to different isobars, a three-dimensional model of temperature-pressure-density is determined.

10. The control method according to claim 9, characterized in that, The method of adjusting the volumetric flow rate of CO2 using an adaptive integral separation PID control algorithm includes the following steps: Determine the volumetric flow rate of CO2 to be injected based on the mass flow rate of CO2. The volumetric flow rate deviation is determined based on the volumetric flow rate of the CO2 to be injected and the current daily CO2 volumetric flow rate. The adaptive integral separation PID control algorithm is used to adjust the opening of the actuator control valve according to the volumetric flow rate deviation, thereby regulating the volumetric flow rate of CO2.

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