Carbon dioxide flooding well three-in-one intelligent monitoring system and monitoring method

Abstract

The application discloses a kind of carbon dioxide oil displacement well three-in-one intelligent monitoring system and monitoring method, comprising: wellhead connector, fixed at casing head gas sampling port, sampling casing gas, determining the pressure value of casing gas, and receiving liquid level reflection wave signal;Automatic liquid level tester, compressed air is manufactured as external pressure type sound emission energy source, and the depth of liquid level is determined;Gas on-line monitor, casing gas collected by wellhead connector is detected, and the carbon dioxide concentration value thereof is determined.Wellhead connector is connected with casing sample gas connector, inner cavity is installed with casing gas solenoid valve for internal pressure sound emission, compressed air solenoid valve for external pressure sound emission and microphone for receiving echo, and internal pressure sound emission or external pressure sound emission is selected according to casing pressure size.The three-in-one intelligent monitoring system can be installed in wellhead for a long time, can simultaneously monitor associated gas carbon dioxide concentration content, casing pressure value and oil well dynamic liquid level data in real time, saves manpower and material resources, and obtains data timely and accurately.

Description

Technical Field

[0001] This invention relates to an oil well monitoring tool, and more particularly to a three-in-one intelligent monitoring system for carbon dioxide-driven oil wells. This invention also relates to a three-in-one intelligent monitoring method for carbon dioxide-driven oil wells, belonging to the technical field of intelligent oil well monitoring instruments. Background Technology

[0002] In recent years, with the increase in the number of carbon dioxide flooding wells, the number of wells requiring monitoring of associated gas has also increased. Current gas sample monitoring methods involve: team members collecting gas samples at the wellhead using a gas extraction device and bringing them back to the plant, where they are then sent to the base monitoring station for analysis. Dynamic fluid level testing requires personnel to carry instruments up to the well for testing, and the fluid level curves are then analyzed using dedicated host computer software to obtain fluid level data. Casing pressure is obtained by manually checking mechanical pressure gauges installed on-site.

[0003] Existing monitoring methods have the following problems: 1. It is labor-intensive and resource-intensive, and the cycle for obtaining the composition of gas samples is long. When monitoring a gas sample from a well, a team of personnel must go to the site to collect the sample, which is then sent to the plant. The plant then dispatches personnel and vehicles to transport the gas sample to the base monitoring station for monitoring and analysis.

[0004] 2. Gas sample data is not timely, and the data is singular and discontinuous. It is impossible to obtain the trend of associated gas carbon dioxide component content, and it is also impossible to analyze well condition information using a single data point.

[0005] 3. Monitoring the fluid level requires manual testing using handheld devices at the well. After testing, the collected curves need to be analyzed using dedicated host computer software to obtain fluid level data. This wastes manpower and resources, and the whole process is cumbersome and has poor real-time performance.

[0006] 4. Checking the casing pressure requires manual inspection of the pressure gauge at the well site, which wastes manpower and has poor real-time performance.

[0007] Chinese invention patent application CN116378638A discloses a dynamic fluid level data monitoring system, device, method, and apparatus, relating to the field of oil well dynamic fluid level monitoring technology. The system includes a remote monitoring device, a sound wave generating device, an echo receiving device, and a data acquisition device. The remote monitoring device sends a first control command to the sound wave generating device; sends a second control command to the echo receiving device; and sends a third control command to the data acquisition device. The sound wave generating device receives the first control command and generates a sound wave based on the first control command. The echo receiving device receives the second control command and acquires the echo signal based on the second control command. The echo signal is then sent to the data acquisition device. The data acquisition device receives the third control command and receives the echo signal based on the third control command. The dynamic fluid level data is calculated from the echo signal and stored.

[0008] This monitoring system can automatically monitor the dynamic fluid level data of oil wells, which improves the efficiency of monitoring work, but it cannot simultaneously monitor the casing gas pressure and the carbon dioxide concentration in the casing gas. Summary of the Invention

[0009] The primary objective of this invention is to overcome the problems existing in the prior art and provide a three-in-one intelligent monitoring system for carbon dioxide flooding wells. This system can be installed at the wellhead for a long period of time and can simultaneously monitor the associated gas carbon dioxide concentration, casing pressure, and oil well dynamic fluid level data in real time, saving manpower and resources, and obtaining data in a timely and accurate manner.

[0010] To solve the above technical problems, the present invention provides a three-in-one intelligent monitoring system for carbon dioxide flooding wells, comprising: The wellhead connector is fixed at the casing gas sampling port to sample casing gas, measure the casing gas pressure, and receive liquid surface reflection wave signals. An automatic liquid level tester uses compressed air as an external pressure sound energy source to measure the depth of the liquid level. The gas online monitoring instrument detects the casing gas collected by the wellhead connector and measures its carbon dioxide concentration.

[0011] Furthermore, the wellhead connector includes: The connector body is cylindrical, with both ends sealed by the connector inner end cap and the connector outer end cap; The wellhead is equipped with a pipe head, the root of which is fixed to the inner end cap of the connector, and the threaded section is screwed onto the wellhead casing gas sampling port to sample the casing gas. The casing sample gas connector is connected to the side wall of the inner end cap of the connector and communicates with the inner cavity of the wellhead assembly pipe head.

[0012] Furthermore, the wellhead connector also includes: The microphone is located inside the wellhead assembly pipe head and fixed at the center of the connector inner end cap. It receives the liquid surface reflected wave signal and converts it into an electrical signal.

[0013] Furthermore, the wellhead connector also includes: The casing gas release pipe has one end passing through the inner end cap of the connector and communicating with the inner cavity of the wellhead assembly pipe head. A casing gas solenoid valve is provided in the middle section, and the other end passes out from the outer end cap of the connector.

[0014] Furthermore, a silencer is installed at the outer port of the sleeve gas release pipe.

[0015] Furthermore, the wellhead connector also includes: The air chamber welding assembly is located inside the connector cylinder. An air chamber injection pipe passes through the outer end cap of the connector and is connected to the inlet of the outer end wall of the air chamber welding assembly; The external pressure sound-generating pipe has one end connected to the outlet of the inner end wall of the gas chamber welding assembly, a compressed air solenoid valve in the middle section, and the other end connected to the inner cavity of the wellhead assembly pipe head.

[0016] Furthermore, a pressure transmitter for detecting the gas pressure in the sleeve is installed inside the connector cylinder.

[0017] Furthermore, the connector outer end cover is equipped with a connector aviation socket for communication connection between the compressed air solenoid valve, the sleeve air solenoid valve, the microphone and the pressure transmitter and the outside world.

[0018] Furthermore, an electric air pump is also installed in the housing of the automatic liquid level tester, and the outlet of the electric air pump is connected to the air chamber injection pipe of the wellhead connector through a compressed air hose.

[0019] Furthermore, the automatic liquid level tester is equipped with an aviation socket for connecting the power supply and signal lines inside and outside the tester.

[0020] Furthermore, the automatic liquid level tester is also equipped with a DTU for wireless communication with the host computer.

[0021] Furthermore, the liquid level tester housing is also equipped with a liquid level test control box, which is used to control the electric air pump when the automatic liquid level tester is used independently.

[0022] Furthermore, the liquid level tester housing is also equipped with a power conversion device to provide power to the electric air pump, the liquid level test control box, and the wellhead connector.

[0023] Furthermore, the housing of the online gas monitor is equipped with: The filter inlet is connected to the casing gas sampling connector via a casing gas sampling hose; The air pump is tested, and its inlet is connected to the outlet of the filter. The carbon dioxide detector has its inlet connected to the outlet of the detection gas pump and is equipped with a carbon dioxide sensor to detect the concentration of carbon dioxide gas. A drain solenoid valve is connected to the drain outlet of the filter and the carbon dioxide detector.

[0024] Furthermore, the gas online monitoring instrument is equipped with an online monitoring power supply in its housing, and the inner wall of the housing is provided with a cable tray.

[0025] Furthermore, the gas online monitor's housing includes an online monitoring and control unit, which comprises an MCU, a detection gas pump control circuit, a carbon dioxide signal acquisition circuit, and a timed drainage control circuit. The MCU uses an STM32F103RET6 chip. The detection gas pump control circuit includes an optocoupler U11 and a transistor Q12. Pin 1 of the optocoupler U11 is connected to a +5V power supply, pin 2 of the optocoupler U11 is connected to the PB3 port of the MCU, pin 3 of the optocoupler U11 is connected to the base of the transistor Q12, the collector of the transistor Q12 is grounded, pin 4 of the optocoupler U11 is connected to a +24V power supply, and the emitter of the transistor Q12 is connected to the +24V power supply and the detection gas pump interface J9.

[0026] Furthermore, in the carbon dioxide signal acquisition circuit: the signal line of the carbon dioxide sensor outputs a carbon dioxide concentration current signal proportional to the carbon dioxide concentration. The negative terminal of the carbon dioxide sensor signal line is grounded, and the positive terminal is connected to one end of resistor R43. The other end of resistor R43 is grounded, converting the carbon dioxide concentration current signal into a voltage sampling signal. After being current-limited by resistor R40, the voltage sampling signal enters the non-inverting input of AD8552 operational amplifier U3A. The output of AD8552 operational amplifier U3A provides the carbon dioxide concentration voltage signal to the PA1 port of the MCU. The MCU calculates the corresponding carbon dioxide concentration value, provides it to the storage unit for storage, and sends it to the display for display.

[0027] Furthermore, the timed drainage control circuit includes an optocoupler U10 and a transistor Q10. Pin 1 of the optocoupler U10 is connected to a +5V power supply, pin 2 of the optocoupler U10 is connected to the PC12 port of the MCU, pin 3 of the optocoupler U10 is connected to the base of the transistor Q10, the collector of the transistor Q10 is grounded, pin 4 of the optocoupler U10 is connected to a +24V power supply, and the emitter of the transistor Q10 is connected to the interface J5 of the +24V power supply and the drainage solenoid valve.

[0028] Furthermore, the online monitoring and control unit is also equipped with a pressure detection circuit, wherein the pressure detection circuit includes: The pressure transmitter outputs a bushing pressure current signal proportional to the bushing pressure. The negative terminal of the pressure transmitter signal line is grounded, and the positive terminal is connected to one end of resistor R42. The other end of resistor R42 is grounded, converting the bushing pressure current signal into a voltage sampling signal. This voltage sampling signal is current-limited by resistor R39 and then enters the non-inverting input of AD8552 operational amplifier U20A. The output of AD8552 operational amplifier U20A provides the bushing pressure voltage signal to the PC2 port of the MCU. The MCU calculates the actual bushing pressure value, stores it in the storage unit, and sends it to the display for display.

[0029] Furthermore, the online monitoring and control unit is also equipped with a bushing gas release control circuit, which includes an optocoupler U9 and a transistor Q8. Pin 1 of the optocoupler U9 is connected to a +5V power supply, pin 2 of the optocoupler U9 is connected to the PC11 port of the MCU, pin 3 of the optocoupler U9 is connected to the base of the transistor Q8, the collector of the transistor Q8 is grounded, pin 4 of the optocoupler U9 is connected to a +24V power supply, and the emitter of the transistor Q8 is connected to the +24V power supply and the interface J4 of the bushing gas solenoid valve.

[0030] Furthermore, the online monitoring and control unit is also equipped with an air chamber inflation control circuit, which includes an optocoupler U7 and a transistor Q11. Pin 1 of the optocoupler U7 is connected to a +5V power supply, pin 2 of the optocoupler U7 is connected to the PD2 port of the MCU, pin 3 of the optocoupler U7 is connected to the base of the transistor Q11, the collector of the transistor Q11 is grounded, pin 4 of the optocoupler U7 is connected to a +24V power supply, and the emitter of the transistor Q11 is connected to the interface J6 of the +24V power supply and the electric air pump.

[0031] Furthermore, the online monitoring and control unit is also equipped with an external pressure sound generation control circuit, which includes an optocoupler U8 and a transistor Q7. Pin 1 of the optocoupler U8 is connected to a +5V power supply, pin 2 of the optocoupler U8 is connected to the PC10 port of the MCU, pin 3 of the optocoupler U8 is connected to the base of the transistor Q7, the collector of the transistor Q7 is grounded, pin 4 of the optocoupler U8 is connected to a +24V power supply, and the emitter of the transistor Q7 is connected to the +24V power supply and the interface J7 of the compressed air solenoid valve.

[0032] Furthermore, the online monitoring and control unit is also equipped with an acoustic signal detection circuit, which includes a microphone interface, a filter circuit, and a TL084 operational amplifier. The signal line of the microphone is connected to the microphone interface. The microphone receives the echo pulse of the liquid surface downhole and converts it into a 0-100mV voltage signal. After being filtered by the filter circuit, the signal enters the non-inverting input of the TL084 operational amplifier. After being amplified by the TL084 operational amplifier, a 0-2.5V acoustic voltage signal is output and provided to the PC0 port of the MCU. The MCU calculates the liquid surface depth value downhole, provides it to the storage unit for storage, and sends it to the display for display.

[0033] Another objective of this invention is to overcome the problems existing in the prior art and provide a three-in-one intelligent monitoring method for carbon dioxide flooding wells, which can simultaneously monitor the associated gas carbon dioxide concentration, casing pressure value and oil well dynamic fluid level data in real time, saving manpower and material resources, and obtaining data in a timely and accurate manner.

[0034] To solve the above technical problems, the present invention provides a three-in-one intelligent monitoring method for carbon dioxide flooding wells, employing a three-in-one intelligent monitoring system for carbon dioxide flooding wells, comprising the following steps in sequence: S1. The pressure transmitter in the wellhead connector measures the casing gas pressure. S2, the MCU calculates the actual bushing pressure value; S3. Determine if the casing gas pressure is greater than the set pressure value. If yes, proceed to step S4; otherwise, proceed to step S5. S4. The MCU sends a signal to open the casing gas solenoid valve. The high-pressure casing gas is suddenly released, causing the gas pressure in the wellhead annular space to fluctuate, thus achieving internal pressure sound generation. Then proceed to step S6. S5. The MCU sends a signal to open the compressed air solenoid valve, and the compressed air enters the wellhead annular space, causing the gas pressure in the wellhead annular space to fluctuate, thus realizing internal pressure sound generation, and then proceeds to step S6. S6. The microphone in the center of the inner end cap of the wellhead connector receives the reflected wave signal from the liquid surface and converts it into an electrical signal. After filtering and amplification, the signal is provided to the MCU, which calculates the liquid surface depth value in the well. S7, the MCU sends a signal to turn on the detection air pump. The gas in the casing enters the carbon dioxide detector after being filtered. The carbon dioxide sensor in the detector outputs a current signal corresponding to the carbon dioxide concentration. S8: The carbon dioxide concentration current signal is converted into a voltage signal and provided to the MCU; S9 and MCU calculate the corresponding carbon dioxide concentration value.

[0035] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. The intelligent monitoring system can be controlled by a remote computer and can test the associated gas carbon dioxide concentration, casing pressure and dynamic fluid level of the well through a remote host computer.

[0036] 2. The remote computer can store, analyze and process the carbon dioxide concentration, casing pressure and dynamic fluid level depth changes obtained from the test, and analyze well condition information based on the curve trend chart.

[0037] 3. It can be installed at the wellhead for a long time to monitor the carbon dioxide concentration, casing pressure and dynamic fluid level in the associated gas of the oil well. The relevant data can be remotely acquired and transmitted via 4G signal. The whole process does not require human intervention, no need to send sample gas for testing and analysis or manually check the mechanical pressure gauge at the wellhead. It has a fast response time, saves manpower and material resources, has strong real-time performance, and greatly improves work efficiency. Attached Figure Description

[0038] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The drawings are provided for reference and illustration only and are not intended to limit the present invention.

[0039] Figure 1 This is a connection diagram of the three-in-one intelligent monitoring system for carbon dioxide-driven oil wells of the present invention; Figure 2 This is a schematic diagram of the internal structure of the automatic liquid level tester in this invention; Figure 3 This is a schematic diagram of the internal structure of the wellhead connector in this invention; Figure 4 This is a diagram showing the internal structure of the online gas monitor in this invention; Figure 5 This is a schematic diagram of the MCU in the electrical control system of this invention; Figure 6 This is a circuit diagram of voltage generation in the electrical control system of the present invention; Figure 7 This is a circuit diagram of the 485 communication circuit in the electrical control system of this invention; Figure 8 This is a circuit diagram of carbon dioxide signal acquisition in the electrical control system of this invention; Figure 9 This is a circuit diagram of the internal pressure sound generation control system in the electrical control system of this invention; Figure 10 This is a circuit diagram of the external pressure sound generation control system in the electrical control system of this invention; In the diagram: 1. Wellhead connector: 1a. Connector inner end cap; 1b. Connector outer end cap; 1c. Wellhead assembly pipe head; 1d. Microphone; 1e. Casing sample gas connector; 1f. External pressure sound-generating pipe; 1g. Compressed air solenoid valve; 1h. Gas chamber welding assembly; 1j. Silencer; 1k. Gas chamber injection pipe; 1m. Casing gas release pipe; 1n. Casing gas solenoid valve; 1p. Pressure transmitter; 1q. Connector aviation socket; 2. Automatic liquid level tester: 2a. Electric air pump; 2b. Air pump outlet; 2c. Liquid level test control box; 2d. Tester aviation socket; 2e. Power adapter; 3. Compressed air hose; 4. Liquid level test harness; 5. Sleeve gas sampling hose; 6. Gas Online Monitoring Instrument: 6a. Filter; 6b. Detection Gas Pump; 6c. Carbon Dioxide Detector; 6d. Drain Solenoid Valve; 6e. Online Monitoring Power Supply; 6f. Online Monitoring Control Unit; 6g. Cable Tray. Detailed Implementation

[0040] In the following description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not mean that the device must have a specific orientation.

[0041] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0043] like Figure 1 , Figure 2 As shown, the three-in-one intelligent monitoring system for carbon dioxide flooding wells of the present invention includes a wellhead connector 1, an automatic fluid level tester 2, and an online gas monitor 6. The wellhead connector 1 includes a connector body, a wellhead assembly pipe head 1c, a casing sample gas connector 1e, a microphone 1d, a casing gas solenoid valve 1n, a gas chamber welding assembly 1h, a compressed air solenoid valve 1g, and a pressure transmitter 1p. The connector body is cylindrical, with both ends sealed by an inner connector end cap 1a and an outer connector end cap 1b. The root of the wellhead assembly pipe head 1c is fixed to the inner connector end cap 1a, and the threaded section is screwed onto the casing gas sampling port at the wellhead to sample casing gas. The casing sample gas connector 1e is connected to the side wall of the inner connector end cap 1a and communicates with the inner cavity of the wellhead assembly pipe head 1c.

[0044] Microphone 1d is located inside the wellhead assembly pipe head 1c and fixed in the center of the connector inner end cap 1a. It receives the liquid surface reflected wave signal and converts it into an electrical signal.

[0045] One end of the casing gas release pipe 1m passes through the inner end cap 1a of the connector and communicates with the inner cavity of the wellhead assembly pipe head 1c. A casing gas solenoid valve 1n is installed in the middle section, and the other end passes through the outer end cap 1b of the connector. A silencer 1j is installed at the outer port of the casing gas release pipe 1m.

[0046] The inner cavity of the connector cylinder is also equipped with a gas chamber welding assembly 1h. The gas chamber injection pipe 1k passes through the outer end cover 1b of the connector and is connected to the inlet of the outer end wall of the gas chamber welding assembly 1h. One end of the external pressure sound-generating pipe 1f is connected to the outlet of the inner end wall of the gas chamber welding assembly 1h. The middle section is equipped with a compressed air solenoid valve 1g, and the other end is connected to the inner cavity of the wellhead assembly pipe head 1c.

[0047] A pressure transmitter 1p is installed inside the connector housing to detect the pressure of the bushing gas.

[0048] The connector aviation socket 1q is installed on the outer end cover 1b of the connector, which is used for the communication connection between the compressed air solenoid valve 1g, the sleeve air solenoid valve 1n, the microphone 1d and the pressure transmitter 1p and the outside world through the liquid level test harness 4.

[0049] like Figure 3 As shown, the automatic liquid level tester 2 also houses an electric air pump 2a within its casing. An air outlet 2b is located on the side wall of the casing, and this outlet 2b is connected to the air chamber injection pipe 1k of the wellhead connector 1 via a compressed air hose 3. An aviation socket 2d is installed on the casing of the automatic liquid level tester 2 for connecting the internal and external power supplies and signal lines. A DTU is also installed within the casing of the automatic liquid level tester 2 for wireless communication with the host computer.

[0050] The electric air pump 2a is centrally controlled by the control unit in the gas online monitor 6. The liquid level tester housing also retains the function of independent use in the non-three-in-one state, including the liquid level test control box 2c and the conversion power supply 2e. The liquid level test control box 2c is used to control the electric air pump 2a when the automatic liquid level tester 2 is used independently. The conversion power supply 2e is used to provide power to the electric air pump 2a, the liquid level test control box 2c and the wellhead connector 1.

[0051] like Figure 4As shown, the gas online monitoring instrument 6 contains a filter 6a, a detection gas pump 6b, a carbon dioxide detector 6c, a drain solenoid valve 6d, an online monitoring control unit 6f, and an online monitoring power supply 6e. The inner wall of the box has a cable tray 6g. The casing sample gas connector 1e on the wellhead connector 1 is connected to the inlet of the filter 6a via the casing gas sampling hose 5. The outlet of the filter 6a is connected to the inlet of the detection gas pump 6b, and the outlet of the detection gas pump 6b is connected to the inlet of the carbon dioxide detector 6c. The carbon dioxide detector 6c contains a carbon dioxide sensor to detect the concentration of carbon dioxide gas. The drain outlets of the filter 6a and the carbon dioxide detector 6c drain water externally through the drain solenoid valve 6d.

[0052] like Figures 5 to 10 As shown, the gas online monitor 6 houses an online monitoring control unit 6f within its enclosure. This unit includes an MCU, a detection gas pump control circuit, a carbon dioxide signal acquisition circuit, a timed drainage control circuit, a casing pressure detection circuit, a casing gas release control circuit, a gas chamber filling control circuit, an external pressure sound generation control circuit, and a sound wave signal detection circuit. The online monitoring control unit 6f also includes a +5V generation circuit and a +3.3V generation circuit, employing a REG1117 voltage regulator chip to provide stable +5V and +3.3V voltages to the control system.

[0053] The MCU uses the STM32F103RET6 chip, which is a microcontroller based on the ARM Cortex-M3 core. It boasts excellent performance and features the following key characteristics: high operating frequency, up to 72 MHz; integrated multiple general-purpose timers, enabling functions such as periodic interrupts, pulse counting, and PWM output; support for various peripheral interfaces, including I2C, SPI, UART, and USB; and built-in 512 KB flash memory and 64 KB SRAM, meeting the storage needs of various complex applications.

[0054] The MCU's PA1 port receives the carbon dioxide concentration signal, the MCU's PC2 port receives the sleeve gas pressure signal, and the MCU's PC0 port receives the echo signal from microphone 1d. The MCU's PC11 port sends a sleeve gas release signal, the MCU's PC12 port sends a timed drainage signal, the MCU's PD2 port sends a gas chamber inflation signal, and the MCU's PC10 port sends an external pressure sound control signal.

[0055] The detection air pump control circuit includes an optocoupler U11 and a transistor Q12. Pin 1 of the optocoupler U11 is connected to the +5V power supply, pin 2 of the optocoupler U11 is connected to the PB3 port of the MCU, pin 3 of the optocoupler U11 is connected to the base of the transistor Q12, the collector of the transistor Q12 is grounded, pin 4 of the optocoupler U11 is connected to the +24V power supply, and the emitter of the transistor Q12 is connected to the +24V power supply and the detection air pump interface J9.

[0056] When the MCU's PB3 port outputs a low level, the output of optocoupler U11 is isolated and connected, and the detection gas pump 6b is powered on and starts working. It collects the gas to be tested on site through the casing sample gas connector 1e of the wellhead connector 1, filters the gas for dust through filter 6a to achieve the cleanliness required by the analyzer, and can also set a pressure reducing valve to reduce the pressure of the casing gas. The filtered casing gas is then sent to the carbon dioxide detector 6c for detection. The carbon dioxide detector 6c is equipped with a carbon dioxide sensor to detect the carbon dioxide concentration in the casing gas. The water generated during the filtration process is discharged periodically through the drain solenoid valve 6d.

[0057] In the carbon dioxide signal acquisition circuit: the carbon dioxide sensor outputs a carbon dioxide concentration current signal proportional to the carbon dioxide concentration. The negative terminal of the carbon dioxide sensor signal line is grounded, and the positive terminal is connected to one end of resistor R43. The other end of resistor R43 is grounded, converting the carbon dioxide concentration current signal into a voltage sampling signal. This voltage sampling signal is current-limited by resistor R40 and then enters the non-inverting input of AD8552 operational amplifier U3A. The output of AD8552 operational amplifier U3A provides the carbon dioxide concentration voltage signal to the PA1 port of the MCU and sends the feedback signal back to the inverting input of AD8552 operational amplifier U3A. The MCU calculates the corresponding carbon dioxide concentration value, provides it to the storage unit for storage, and sends it to the display for display.

[0058] Carbon dioxide sensors can employ NDIR infrared gas sensors, which utilize non-dispersive infrared technology based on gas absorption theory. The working principle of NDIR infrared gas sensors is based on the selective absorption characteristics of different gas molecules in the near-infrared spectrum. It uses the relationship between gas concentration and absorption intensity (Lambert-Beer law) to identify gas components and determine their concentrations.

[0059] When infrared light passes through the gas being measured, the different internal structures of the molecules determine their selective absorption of different wavelengths of light. That is, the substances can only absorb light of a certain wavelength; specifically, these gas molecules absorb infrared light of a particular wavelength, and this absorption follows the Lambert-Beer absorption law. This gas sensor device is an optical sensor composed of an infrared light source, optical path, infrared detector, circuitry, and software algorithms, used to detect compounds.

[0060] The timed drainage control circuit includes an optocoupler U10 and a transistor Q10. Pin 1 of optocoupler U10 is connected to a +5V power supply, pin 2 is connected to the PC12 port of the MCU, pin 3 is connected to the base of transistor Q10, the collector of transistor Q10 is grounded, pin 4 is connected to a +24V power supply, and the emitter of transistor Q10 is connected to the +24V power supply and the interface J5 of the drainage solenoid valve 6d. When drainage is needed, the PC12 port of the MCU outputs a low level, the output of optocoupler U10 is isolated and turned on, the drainage solenoid valve 6d is energized to drain water, and it closes when drainage is finished.

[0061] In the casing pressure detection circuit: a three-wire 4-20mA pressure transmitter is used, which can convert the gas pressure parameter sensed by the pressure sensing element sensor into a standard 4-20mA current signal. The signal line output of pressure transmitter 1p outputs a casing gas pressure current signal proportional to the casing gas pressure. The negative terminal of pressure transmitter 1p signal line is grounded, and the positive terminal is connected to one end of resistor R42. The other end of resistor R42 is grounded, converting the casing gas pressure current signal into a voltage sampling signal. After current limiting by resistor R39, this voltage sampling signal enters the non-inverting input of AD8552 operational amplifier U20A. The output of AD8552 operational amplifier U20A provides the casing gas pressure voltage signal to the PC2 port of the MCU. At the same time, the feedback signal is sent to the inverting input of AD8552 operational amplifier U20A. The MCU calculates the actual casing gas pressure value, provides it to the storage unit for storage, and sends it to the display for display.

[0062] This system uses the echo method to monitor the dynamic liquid level. The principle is to use compressed air or pressurized tubing air as a sound source to generate sound waves. When the instrument is working normally, it can continuously monitor the liquid level without manual intervention. After setting the corresponding parameters through the main control circuit, the corresponding solenoid valve is opened to generate sound waves. The reflected wave signal from the liquid level is then received by the microphone 1D and converted into an electrical signal. After filtering, the MCU will collect the reflected wave data and obtain the liquid level data through the relevant liquid level calculation algorithm.

[0063] The principle of using casing gas within the annular space to generate sound is an internal pressure sound generation method. When the casing gas pressure in the well being logged is greater than 0.5 MPa (adjustable), the casing gas can be directly used as the sound energy source. Its sound generation principle involves suddenly releasing a certain volume of high-pressure casing gas, causing pressure fluctuations in the gas within the annular space at the wellhead to produce sound. The advantages of using casing gas for sound generation are that it requires no auxiliary consumables, generates no heat or ignition source, and is absolutely safe during use.

[0064] The sound generation method utilizes compressed air and is an external pressure type. When the casing gas pressure in the well being logged is less than 0.5 MPa (adjustable), compressed air can be used as a sound source. Its sound generation principle is to suddenly release a certain volume of compressed air, causing the gas pressure in the annular space at the wellhead to fluctuate and generate sound.

[0065] The liquid level test section can be set to different working modes, including compressed air mode and release jacket gas mode. The mode can be set according to the jacket pressure value.

[0066] The online monitoring and control unit 6f also includes a bushing gas release control circuit, which includes an optocoupler U9 and a transistor Q8. Pin 1 of the optocoupler U9 is connected to the +5V power supply, pin 2 of the optocoupler U9 is connected to the PC11 port of the MCU, pin 3 of the optocoupler U9 is connected to the base of the transistor Q8, the collector of the transistor Q8 is grounded, pin 4 of the optocoupler U9 is connected to the +24V power supply, and the emitter of the transistor Q8 is connected to the +24V power supply and the interface J4 of the bushing gas solenoid valve 1n.

[0067] When the MCU's PC11 port outputs a low level, the output of the optocoupler U9 is isolated and turned on, which energizes and opens the bushing gas solenoid valve 1n. The bushing gas is released outward through the bushing gas release pipe 1m, generating internal pressure and producing sound. The outer port of the bushing gas release pipe 1m is silenced by the muffler 1j.

[0068] The air chamber inflation control circuit includes an optocoupler U7 and a transistor Q11. Pin 1 of optocoupler U7 is connected to a +5V power supply, pin 2 is connected to the PD2 port of the MCU, pin 3 is connected to the base of transistor Q11, the collector of transistor Q11 is grounded, pin 4 is connected to a +24V power supply, and the emitter of transistor Q11 is connected to the +24V power supply and the interface J6 of the electric air pump 2a. When the PD2 port of the MCU outputs a low level, its output terminal is isolated and connected, and the electric air pump 2a operates, inflating and pressurizing the inner cavity of the air chamber welding assembly 1h through the compressed air hose 3 and the air chamber injection pipe 1k.

[0069] The online monitoring and control unit 6f also includes an external pressure sound generation control circuit, which comprises an optocoupler U8 and a transistor Q7. Pin 1 of optocoupler U8 is connected to a +5V power supply, pin 2 is connected to the PC10 port of the MCU, pin 3 is connected to the base of transistor Q7, the collector of transistor Q7 is grounded, pin 4 is connected to a +24V power supply, and the emitter of transistor Q7 is connected to the +24V power supply and the interface J7 of the compressed air solenoid valve 1g. When the PC10 port of the MCU outputs a low level, the output of optocoupler U8 is isolated and turned on, the compressed air solenoid valve 1g is energized and opened, and the compressed air in the gas chamber welding assembly 1h is injected into the wellhead casing through the external pressure sound generation pipe 1f.

[0070] The online monitoring and control unit 6f also includes an acoustic signal detection circuit, which includes a microphone interface, a filter circuit, and a TL084 operational amplifier. The signal line of the microphone 1d is connected to the microphone interface. The microphone 1d receives the downhole liquid surface echo pulse and converts it into a 0-100mV voltage signal. The filter circuit includes resistor R25, capacitor C19, resistor R26, resistor R27, capacitor C12, etc. After the liquid surface echo pulse voltage signal is filtered by two stages of RC, it enters the non-inverting input of the TL084 operational amplifier. After being amplified by the TL084 operational amplifier, it outputs a 0-2.5V acoustic voltage signal to the PC0 port of the MCU. The MCU calculates the downhole liquid surface depth value, provides it to the storage unit for storage, and sends it to the display for display.

[0071] The three-in-one intelligent monitoring method for carbon dioxide flooding wells includes the following steps: S1, the pressure transmitter 1p in the wellhead connector 1 measures the casing gas pressure; S2, the MCU calculates the actual bushing pressure value; S3. Determine if the casing gas pressure is greater than the set pressure value. If yes, proceed to step S4; otherwise, proceed to step S5. S4. The MCU sends a signal to open the casing gas solenoid valve 1n. The high-pressure casing gas is suddenly released, causing the gas pressure in the wellhead annulus space to fluctuate, realizing internal pressure sound generation, and then proceeding to step S6. S5. The MCU sends a signal to open the compressed air solenoid valve 1g, and the compressed air enters the wellhead annular space, causing the gas pressure in the wellhead annular space to fluctuate, thus realizing internal pressure sound generation, and then proceeds to step S6. S6. Microphone 1d at the center of the inner end cap of the wellhead connector 1 receives the liquid surface reflected wave signal and converts it into an electrical signal. After filtering and amplification, the signal is provided to the MCU, which calculates the liquid surface depth value in the well. S7. The MCU sends a signal to turn on the detection air pump 6b. The gas in the sleeve enters the carbon dioxide detector 6c after being filtered. The carbon dioxide sensor in the detector outputs a current signal corresponding to the carbon dioxide concentration. S8: The carbon dioxide concentration current signal is converted into a voltage signal and provided to the MCU; S9 and MCU calculate the corresponding carbon dioxide concentration value.

[0072] The online monitoring and control unit 6f is also equipped with a 485 communication circuit, which uses an ADM2587 module. The 485 communication port of the ADM2587 module is connected to the DTU. The DTU is a wireless terminal device used to convert serial port data into IP data or IP data into serial port data for transmission through a wireless communication network.

[0073] The online monitoring and control unit 6f transmits the final liquid level, pressure, and carbon dioxide concentration values ​​to the monitoring center computer via 4G signal. The monitoring center computer stores, analyzes, and processes the data to achieve remote automatic testing. The entire process is automated and can be achieved without human intervention.

[0074] The above description is merely a preferred embodiment of the present invention, showing and describing the basic principles, main features, and advantages of the present invention. It is not intended to limit the scope of patent protection of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. In addition to the above embodiments, the present invention may have other implementations without departing from the spirit and scope of the invention. Various changes and modifications to the present invention are possible, and all technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents. Technical features not described in the present invention can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A three-in-one intelligent monitoring system for carbon dioxide flooding oil wells, characterized in that, include: Wellhead connector (1) is fixed at the wellhead gas sampling port to sample the casing gas, measure the pressure value of the casing gas, and receive the liquid surface reflection wave signal. The wellhead connector (1) includes a connector cylinder, an air passage for collecting casing gas disposed in the connector cylinder, an internal pressure sound-generating air passage for releasing casing gas to generate internal pressure sound waves, and a microphone (1d) for receiving liquid surface reflected waves; the wellhead connector (1) is also provided with a casing sample gas connector (1e) that communicates with the air passage for collecting casing gas. Automatic liquid level tester (2) generates compressed air as an external pressure sound energy source to measure the liquid level depth; The gas online monitoring instrument (6) is connected to the wellhead connector (1) through the casing sample gas connector (1e) to detect the casing gas collected by the wellhead connector (1) and determine its carbon dioxide concentration value. The gas online monitor (6) is equipped with an online monitoring control unit (6f) in its housing. The online monitoring control unit (6f) is equipped with an MCU. The MCU is electrically connected to the automatic liquid level tester (2), the detection component of the gas online monitor (6), and the pressure transmitter (1p), microphone (1d), and internal pressure sound control valve in the wellhead connector (1). It is used to uniformly receive casing pressure signal, carbon dioxide concentration signal and liquid surface reflection wave signal, and control the coordinated operation of the automatic liquid level tester (2) and the gas online monitor (6). The online monitoring and control unit (6f) is also equipped with an acoustic signal detection circuit, which includes a microphone interface, a filter circuit and a TL084 operational amplifier. The signal line of the microphone (1d) is connected to the microphone interface. The microphone (1d) receives the liquid surface echo pulse from the well and converts it into a 0-100mV voltage signal. After being filtered by the filter circuit, the signal enters the non-inverting input of the TL084 operational amplifier. After being amplified by the TL084 operational amplifier, the 0-2.5V acoustic voltage signal is output and provided to the PC0 port of the MCU. The online monitoring and control unit (6f) is also equipped with a carbon dioxide signal acquisition circuit. The signal line of the carbon dioxide sensor outputs a carbon dioxide concentration current signal that is proportional to the carbon dioxide concentration. The negative end of the carbon dioxide sensor signal line is grounded, and the positive end is connected to one end of resistor R43. The other end of resistor R43 is grounded, converting the carbon dioxide concentration current signal into a voltage sampling signal. After being current-limited by resistor R40, the voltage sampling signal enters the non-inverting input of AD8552 operational amplifier U3A. The output of AD8552 operational amplifier U3A provides the carbon dioxide concentration voltage signal to the PA1 port of the MCU. The online monitoring and control unit (6f) is also equipped with a casing pressure detection circuit. In the casing pressure detection circuit, the signal line of the pressure transmitter (1p) outputs a casing pressure current signal that is proportional to the casing pressure. The negative terminal of the signal line of the pressure transmitter (1p) is grounded, and the positive terminal is connected to one end of the resistor R42. The other end of the resistor R42 is grounded. The casing pressure current signal is converted into a voltage sampling signal. After being current-limited by the resistor R39, the voltage sampling signal enters the non-inverting input of the AD8552 operational amplifier U20A. The output of the AD8552 operational amplifier U20A provides the casing pressure voltage signal to the PC2 port of the MCU.

2. The carbon dioxide flooding well three-in-one intelligent monitoring system according to claim 1, characterized in that, The wellhead connector (1) also includes: The connector body is cylindrical and its two ends are closed by the connector inner end cap (1a) and the connector outer end cap (1b); The wellhead is equipped with a pipe head (1c), the root of which is fixed to the inner end cap (1a) of the connector, and the threaded section is screwed onto the wellhead casing gas sampling port to sample the casing gas. The casing sample gas connector (1e) is connected to the side wall of the inner end cap (1a) of the connector and communicates with the inner cavity of the wellhead assembly pipe head (1c).

3. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 2, characterized in that, The microphone (1d) is located inside the wellhead assembly pipe head (1c) and fixed to the center of the connector inner end cap (1a).

4. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 3, characterized in that, The internal pressure sound-generating air path includes: The casing gas release pipe (1m) has one end passing through the inner end cap (1a) of the connector and communicating with the inner cavity of the wellhead assembly pipe head (1c). The middle section is equipped with a casing gas solenoid valve (1n) as an internal pressure sound control valve, and the other end passes through the outer end cap (1b) of the connector.

5. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 4, characterized in that: A silencer (1j) is installed at the outer port of the gas release pipe (1m).

6. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 4, characterized in that: The wellhead connector (1) also includes: The air chamber welding assembly (1h) is located inside the connector cylinder. The air chamber injection pipe (1k) passes through the outer end cap (1b) of the connector and is connected to the inlet of the outer end wall of the air chamber welding assembly (1h); The external pressure sound-generating pipe (1f) is connected at one end to the outlet of the inner end wall of the gas chamber welding assembly (1h), and is equipped with a compressed air solenoid valve (1g) in the middle section. The other end is connected to the inner cavity of the wellhead assembly pipe head (1c).

7. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 6, characterized in that: The inner cavity of the connector cylinder is equipped with a pressure transmitter (1p) for detecting the gas pressure in the sleeve.

8. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 7, characterized in that: The connector outer end cover (1b) is equipped with a connector aviation socket (1q) for communication connection between the compressed air solenoid valve (1g), the sleeve air solenoid valve (1n), the microphone (1d) and the pressure transmitter (1p) and the outside world.

9. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 6, characterized in that: The automatic liquid level tester (2) is also equipped with an electric air pump (2a) in its housing. The outlet of the electric air pump (2a) is connected to the air chamber injection pipe (1k) of the wellhead connector (1) through a compressed air hose (3).

10. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 9, characterized in that: The automatic liquid level tester (2) is equipped with an aviation socket (2d) for connecting the power supply and signal lines inside and outside the box.

11. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 10, characterized in that: The automatic liquid level tester (2) is also equipped with a DTU for wireless communication with the host computer.

12. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 9, characterized in that: The liquid level tester housing is also equipped with a liquid level test control box (2c) for controlling the electric air pump (2a) when the automatic liquid level tester (2) is used independently.

13. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 12, characterized in that: The liquid level tester housing is also equipped with a power conversion power supply (2e) for supplying power to the electric air pump (2a), the liquid level test control box (2c), and the wellhead connector (1).

14. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 9, characterized in that, The housing of the gas online monitoring instrument (6) is equipped with: The filter (6a) has its inlet connected to the casing gas sampling hose (5) via the casing gas sampling hose (1e); The air pump (6b) is connected at its inlet to the outlet of the filter (6a); The carbon dioxide detector (6c) has its inlet connected to the outlet of the detection gas pump (6b) and is equipped with a carbon dioxide sensor to detect the concentration of carbon dioxide gas. The drain solenoid valve (6d) is connected to the drain outlet of the filter (6a) and the carbon dioxide detector (6c).

15. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 14, characterized in that, The gas online monitoring instrument (6) is equipped with an online monitoring power supply (6e) in its housing and a wire groove (6g) on ​​the inner wall of the housing.

16. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 14, characterized in that, The online monitoring and control unit (6f) is also equipped with a detection air pump control circuit. The MCU adopts an STM32F103RET6 chip. The detection air pump control circuit includes an optocoupler U11 and a transistor Q12. Pin 1 of the optocoupler U11 is connected to a +5V power supply. Pin 2 of the optocoupler U11 is connected to the PB3 port of the MCU. Pin 3 of the optocoupler U11 is connected to the base of the transistor Q12. The collector of the transistor Q12 is grounded. Pin 4 of the optocoupler U11 is connected to a +24V power supply. The emitter of the transistor Q12 is connected to the +24V power supply and the detection air pump interface J9.

17. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 11, characterized in that, The online monitoring and control unit (6f) is also equipped with a timed drainage control circuit, which includes an optocoupler U10 and a transistor Q10. Pin 1 of the optocoupler U10 is connected to a +5V power supply, pin 2 of the optocoupler U10 is connected to the PC12 port of the MCU, pin 3 of the optocoupler U10 is connected to the base of the transistor Q10, the collector of the transistor Q10 is grounded, pin 4 of the optocoupler U10 is connected to a +24V power supply, and the emitter of the transistor Q10 is connected to the +24V power supply and the interface J5 of the drainage solenoid valve (6d).

18. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 11, characterized in that, The online monitoring and control unit (6f) is also equipped with a bushing gas release control circuit, which includes an optocoupler U9 and a transistor Q8. Pin 1 of the optocoupler U9 is connected to a +5V power supply, pin 2 of the optocoupler U9 is connected to the PC11 port of the MCU, pin 3 of the optocoupler U9 is connected to the base of the transistor Q8, the collector of the transistor Q8 is grounded, pin 4 of the optocoupler U9 is connected to a +24V power supply, and the emitter of the transistor Q8 is connected to the +24V power supply and the interface J4 of the bushing gas solenoid valve (1n).

19. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 11, characterized in that, The online monitoring and control unit (6f) is also equipped with an air chamber inflation control circuit, which includes an optocoupler U7 and a transistor Q11. Pin 1 of the optocoupler U7 is connected to a +5V power supply, pin 2 of the optocoupler U7 is connected to the PD2 port of the MCU, pin 3 of the optocoupler U7 is connected to the base of the transistor Q11, the collector of the transistor Q11 is grounded, pin 4 of the optocoupler U7 is connected to a +24V power supply, and the emitter of the transistor Q11 is connected to the +24V power supply and the interface J6 of the electric air pump (2a).

20. The three-in-one intelligent monitoring system for carbon dioxide flooding wells according to claim 11, characterized in that, The online monitoring and control unit (6f) is also equipped with an external pressure sound generation control circuit, which includes an optocoupler U8 and a transistor Q7. Pin 1 of the optocoupler U8 is connected to a +5V power supply, pin 2 of the optocoupler U8 is connected to the PC10 port of the MCU, pin 3 of the optocoupler U8 is connected to the base of the transistor Q7, the collector of the transistor Q7 is grounded, pin 4 of the optocoupler U8 is connected to a +24V power supply, and the emitter of the transistor Q7 is connected to the +24V power supply and the interface J7 of the compressed air solenoid valve (1g).

21. A three-in-one intelligent monitoring method for carbon dioxide flooding wells, employing the three-in-one intelligent monitoring system for carbon dioxide flooding wells as described in claim 1, characterized in that, The steps are as follows: S1, the pressure transmitter (1p) in the wellhead connector (1) measures the casing gas pressure; S2, the MCU calculates the actual bushing pressure value; S3. Determine if the casing gas pressure is greater than the set pressure value. If yes, proceed to step S4; otherwise, proceed to step S5. S4. The MCU sends a signal to open the casing gas solenoid valve (1n). The high-pressure casing gas is suddenly released, causing the gas pressure in the wellhead annular space to fluctuate, thus achieving internal pressure sound generation. Then proceed to step S6. S5. The MCU sends a signal to open the compressed air solenoid valve (1g), and the compressed air enters the wellhead annular space, causing the gas pressure in the wellhead annular space to fluctuate, thereby realizing external pressure sound generation, and then proceeds to step S6. S6, Wellhead Connector (1) The microphone (1d) in the center of the inner end cap receives the liquid surface reflected wave signal and converts it into an electrical signal. After filtering and amplification, it is provided to the MCU, and the MCU calculates the liquid surface depth value in the well. S7. The MCU sends a signal to turn on the detection gas pump (6b). The gas in the casing enters the carbon dioxide detector (6c) after being filtered. The carbon dioxide sensor in the detector outputs a current signal corresponding to the carbon dioxide concentration. S8: The carbon dioxide concentration current signal is converted into a voltage signal and provided to the MCU; S9, the MCU calculates the corresponding carbon dioxide concentration value; S10, the MCU stores and analyzes the casing pressure value obtained in step S2, the carbon dioxide concentration value obtained in step S9, and the liquid level depth value obtained in step S6, and sends them to the host computer through the remote communication unit.

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