A gas-water alternating injection device and method based on carbon dioxide enhanced recovery

Abstract

The application discloses a kind of gas-water alternating injection device and method based on carbon dioxide extraction, to solve the technical problem of long response time of existing gas channeling control technology depends on manual analysis, the gas-water alternating injection device includes production well monitoring device, injection well monitoring device and control device, by integrated monitoring and control technology, overall monitoring and accurate control to oil and gas exploitation process are realized.The gas-water alternating injection method is based on the optimization of gas-water alternating injection strategy by gas-water alternating injection device, the maximum injection capacity is obtained by dynamic seepage capacity, and the control effect of gas channeling is ensured by accurate water slug injection.The above-mentioned device and method reduce the system fluctuation caused by manual operation, improve the response speed and the accuracy of operation, and the reliability and stability of the system.

Description

Technical Field

[0001] This invention relates to the field of oilfield production and gas extraction, and mainly to a gas-water alternating injection device and method based on carbon dioxide extraction. Background Technology

[0002] Traditional oilfield development methods often fail to effectively recover residual oil from reservoirs, leading to resource waste and environmental burden. Therefore, developing new technologies to improve oil and gas recovery rates is of paramount importance.

[0003] Currently, commonly used methods for enhancing oil recovery in oilfield development include waterflooding, steam flooding, and gas flooding. While these methods improve oil and gas extraction efficiency to some extent, they also have limitations. Waterflooding is ineffective in high water-cut conditions, and steam flooding is costly and energy-intensive. With the maturation of CCUS-EOR (Carbon Capture, Utilization, and Storage - Enhanced Oil Recovery) technology, more and more oilfields are adopting carbon dioxide flooding technology. Carbon dioxide flooding technology captures carbon dioxide emitted from industry and injects it into the reservoir, reducing the viscosity of crude oil, increasing reservoir pressure, and driving the crude oil towards the wellhead. However, during carbon injection, carbon dioxide channeling may occur, affecting oil and gas recovery efficiency and potentially causing well failure and environmental pollution.

[0004] To prevent gas channeling, actual oil and gas reservoir management often employs alternating injection of carbon dioxide and water slugs. Water slugs are used to prevent rapid carbon dioxide channeling. When gas channeling occurs in the affected well, manual analysis confirms the situation, and water injection is initiated in the carbon injection well. After a period of water injection, carbon injection is resumed to prevent gas channeling. However, in practice, determining gas channeling in the affected well and initiating water injection in the carbon injection well requires time. Often, reservoir engineers analyze the affected well's condition, and on-site production engineers shut down the affected well while simultaneously closing the carbon injection valve and opening the water injection valve to resume the water injection process. This process is not only time-consuming but also carries operational risks. Therefore, a device and method are needed to control the alternating gas-water injection process during carbon dioxide recovery. This method should monitor changes in parameters such as carbon content, production rate, and water cut in the affected well in real time, determine the gas channeling time, and achieve rapid response and effective control of gas channeling, thereby improving oil and gas recovery and reducing on-site operational risks. Summary of the Invention

[0005] The purpose of this invention is to provide a gas-water alternating injection device and method based on carbon dioxide extraction, so as to overcome the shortcomings of existing technologies that rely on manual analysis and have long response times.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A gas-water alternating injection device based on carbon dioxide extraction includes a production well monitoring device, an injection well monitoring device, and a control device. The control device, as the central hub of the entire gas-water alternating injection device, is responsible for receiving monitoring data and controlling the opening and closing of various valves. It is equipped with a control program to respond to and process the received signals. The control device is connected to the production well monitoring device and the injection well monitoring device respectively to realize automated gas-water alternating injection, quickly control gas leakage, and reduce wellhead operation risks. The well monitoring device is installed in the well and on the pipeline connected to the well; The injection well monitoring device is arranged on the injection well and the water injection pipeline and carbon injection pipeline connected to the injection well.

[0007] Production wells serve as the extraction points for oil and gas, while injection wells serve as the injection points for carbon dioxide and water.

[0008] Furthermore, the produced well is connected to a separator via a pipeline. The separator is connected to one end of a gas phase pipeline and one end of a liquid phase pipeline to separate the produced oil and gas mixture into gas and liquid. The gas and liquid enter different pipelines for easy detection. The other ends of the gas phase pipeline and the other ends of the liquid phase pipeline are connected to the oil pipeline, respectively. After being detected in the gas phase pipeline and the liquid phase pipeline, the gas and liquid are output from the oil pipeline.

[0009] Furthermore, the production well monitoring device includes: The produced pressure detector is installed on the pipeline connecting the produced well to the separator to collect pressure data of the produced material in the produced well in real time, providing operating parameters for the control device; The production control valve is located on the pipeline connecting the production well to the separator. It controls the flow of the produced fluid from the production well and can be opened and closed according to the signal from the control device. It is closed when the control device receives a gas leakage signal and opened when mining operations are carried out. A carbon dioxide gas detector is installed on the gas phase pipeline to collect real-time data on the carbon dioxide content in the sample and send a signal to the control device when the carbon dioxide concentration is abnormal. The flow meter is installed on the liquid phase pipeline to measure the flow rate in the liquid phase pipeline, provide parameters of fluid flow rate to the control device, and provide the control device with the basic data required to calculate the maximum injection pressure. A water content analyzer is installed on the liquid phase pipeline to monitor the water content of the liquid in the pipeline, providing basic data on changes in the water content of the extracted material for the control device.

[0010] Furthermore, the injection well monitoring device includes: The water injection control valve is located on the water injection pipeline to control the fluid flow on the pipeline and adjust the water injection volume according to the instructions of the control device. The water injection pressure detector is installed on the water injection pipeline to monitor the pressure changes of the liquid in the pipeline and transmit the data to the control device. Carbon injection control valve, located on the carbon injection pipeline, controls the injection of carbon dioxide and opens and closes according to the signal from the control device. The carbon injection pressure detector is installed on the carbon injection pipeline to detect changes in gas pressure in the pipeline and transmit the data to the control device in real time.

[0011] A gas-water alternating injection method based on carbon dioxide extraction is implemented using the aforementioned gas-water alternating injection device based on carbon dioxide extraction; the gas-water alternating injection method based on carbon dioxide extraction includes the following steps: S1, the control device collects parameters of the production well and injection well obtained in real time by the production well monitoring device and the injection well monitoring device; S2, the control device receives a signal that gas leakage has occurred in the production well, sends a signal to the production well monitoring device to shut down the production well, and at the same time sends a signal to the injection well monitoring device to initiate water injection slug. S3, the control device calculates the maximum water injection capacity and controls the injection well monitoring device to inject water into the injection well at a certain flow rate; S4, after the set water injection volume is reached, the control device sends a signal to the injection well monitoring device to stop water injection and resume carbon injection; S5. After gas leakage is effectively controlled, the control device sends a signal to the production well monitoring device to reopen the production well.

[0012] Furthermore, the control device calculates the maximum water injection capacity using the following method: S301, the carbon injection pipeline pressure data is obtained through the injection well monitoring device, and the reservoir injection pressure is calculated.

[0013] Where Pinjection is the reservoir injection pressure, Py is the pressure data monitored by the carbon injection pressure detector, ρ(CO2) is the density of carbon dioxide, g is the gravitational acceleration, and h is the reservoir injection depth. Pressure data and product water cut of the produced well are obtained through the production well monitoring device, and the bottom hole flowing pressure of the produced well is calculated by combining the wellbore gradient.

[0014]

[0015] Wherein, Pflow is the bottom-hole flowing pressure of the production well, Pd is the pressure data monitored by the production pressure detector, ρ(mixture) is the density of the mixture, ρw is the density of water, fw is the water cut, and ρo is the density of oil. S302, calculate the dynamic seepage capacity.

[0016]

[0017] Where Δ is the dynamic seepage capacity, qw is the water production, Kw is the water phase permeability, h is the formation thickness, B is the volume coefficient, μ is the fluid viscosity, re is the supply radius, and rw is the well radius. S303, the maximum injection pressure at the bottom of the well is calculated based on the maximum injection pressure of the injection pump.

[0018] The injection pressure differential was calculated using the maximum injection pressure at the bottom of the well.

[0019] The maximum injection capacity is calculated using injection pressure differential and dynamic seepage capacity.

[0020] Where p_water is the maximum injection pressure at the bottom of the well, p_ppump is the maximum injection pressure of the injection pump, ρ(water) is the density of water, g is the acceleration due to gravity, h is the depth at the bottom of the well, and q_injection is the maximum injection capacity.

[0021] Furthermore, the control device determines the sampling frequency of parameters such as flow rate and carbon dioxide content of the well by measuring the changes in water content and flow rate of the extracted material.

[0022] Furthermore, if the change in moisture content is less than 5% or the change in flow rate is less than 20%, the flow rate and carbon dioxide content values ​​should be recorded every 3 days.

[0023] Furthermore, if the water content changes by more than 5% or the flow rate changes by more than 20%, the flow rate and carbon dioxide content values ​​should be recorded every 3 hours. Furthermore, when the production well monitoring device detects that the carbon dioxide content in the produced material of the production well is greater than 20%, it sends a gas leakage signal from the production well to the control device.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects: A gas-water alternating injection device based on carbon dioxide extraction achieves comprehensive monitoring and precise control of the oil and gas extraction process through integrated monitoring and control technology. This device can collect key parameters from both production and injection wells in real time, rapidly responding to changes in reservoir conditions, thereby improving oil and gas recovery rates and operational safety. Automated operation reduces manual intervention, lowers operating costs and human error, while improving response speed and operational accuracy. The device can also effectively detect and control gas channeling, protecting well production efficiency, reducing greenhouse gas emissions, and meeting environmental protection requirements. Furthermore, the integrated design and automated operation of this gas-water alternating injection device improve reservoir management efficiency, extend well lifespan, and provide a new solution for oilfield development.

[0025] A gas-water alternating injection method based on carbon dioxide extraction significantly improves oil and gas recovery and reduces environmental impact by optimizing the gas-water alternating injection strategy. This method can respond rapidly upon detecting signs of gas channeling, closing the production channel and carbon injection channel while simultaneously opening the water injection channel to prevent gas channeling and reduce its impact on oil and gas recovery. The method also includes dynamically adjusting water and carbon injection strategies based on real-time data. Maximum water injection capacity is determined through dynamic seepage capacity, and precise injection of water slugs ensures effective control of gas channeling, ensuring effective distribution of carbon dioxide or water slugs in the reservoir, reducing oil and gas loss and environmental impact. Simultaneously, automated control reduces on-site operations and lowers safety risks for operators. Furthermore, the automated system reduces system fluctuations caused by manual operation, minimizes human intervention, lowers operating costs and human error, while improving response speed and operational accuracy, thus enhancing the reliability and stability of the entire injection system. The flexibility and adaptability of the gas-water alternating injection method based on carbon dioxide extraction allow it to be flexibly adjusted according to changes in reservoir conditions, enabling data-driven decision-making and providing a new and efficient solution for oilfield development. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a gas-water alternating injection device based on carbon dioxide extraction in an embodiment of the present invention.

[0027] Figure 2 This is a schematic diagram of a gas-water alternating injection method based on carbon dioxide extraction in an embodiment of the present invention.

[0028] Figure 3 This is a schematic diagram illustrating the calculation of maximum water injection capacity in a gas-water alternating injection method based on carbon dioxide extraction in an embodiment of the present invention.

[0029] In the diagram, 1 is a carbon dioxide gas detector; 2 is a flow meter; 3 is a water cut detector; 4 is a produced pressure detector; 5 is a water injection control valve; 6 is a carbon injection control valve; 7 is a produced control valve; 8 is a water injection pressure detector; 9 is a carbon injection pressure detector; 10 is an oil pipeline; 11 is a water injection pipeline; 12 is a carbon injection pipeline; 13 is a produced well; 14 is an injection well; 15 is a separator; 16 is a control device; 17 is a gas phase pipeline; and 18 is a liquid phase pipeline. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0032] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0033] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a number" means two or more, unless otherwise explicitly specified.

[0034] Example 1: like Figure 1The diagram shown is a structural schematic of a gas-water alternating injection device based on carbon dioxide extraction provided in an embodiment of the present invention. It includes a production well monitoring device, an injection well monitoring device, and a control device 16. The control device 16 serves as the central hub of the entire gas-water alternating injection device, responsible for receiving monitoring data and controlling the opening and closing of each valve. It is equipped with a control program to respond to and process the received signals. The control device 16 is connected to the production well monitoring device and the injection well monitoring device respectively to realize automated gas-water alternating injection, quickly control gas leakage, and reduce wellhead operation risks. The well monitoring device is installed in well 13 and on the pipeline connected to well 13; The injection well monitoring device is arranged on the injection well 14 and the water injection pipeline 11 and carbon injection pipeline 12 connected to the injection well 14.

[0035] Well 13 is the production point for oil and gas, and well 14 is the injection point for carbon dioxide and water.

[0036] Preferably, in this embodiment, the production well 13 is connected to a separator 15 via a pipeline. The separator 15 is connected to one end of a gas phase pipeline 17 and one end of a liquid phase pipeline 18 to separate the produced oil and gas mixture into gas and liquid. The gas and liquid enter different pipelines for easy detection. The other end of the gas phase pipeline 17 and the other end of the liquid phase pipeline 18 are respectively connected to the oil pipeline 10. After being detected in the gas phase pipeline 17 and the liquid phase pipeline 18, the gas and liquid are output from the oil pipeline 10.

[0037] Preferably, the well monitoring device in this embodiment includes: The pressure detector 4 is installed on the pipeline connecting the separator 15 to the production well 13 to collect pressure data of the produced material in the production well 13 in real time, and to provide operating parameters for the control device 16. The production control valve 7 is arranged on the pipeline connecting the production well 13 to the separator 15 to control the flow of the produced fluid from the production well 13. It can be opened and closed according to the signal of the control device 16. It is closed when the control device 16 receives the gas leakage signal and opened when mining is carried out. A carbon dioxide gas detector 1 is installed on the gas phase pipeline 17 to collect real-time data on the carbon dioxide content in the sample and send a signal to the control device 16 when the carbon dioxide concentration is abnormal. Flow meter 2 is arranged on liquid phase pipeline 18 to measure the flow rate in liquid phase pipeline 18, and provides parameters of fluid flow rate to control device 16, providing basic data for control device 16 to calculate the maximum water injection pressure. The water content detector 3 is installed on the liquid phase pipeline 18 to monitor the water content of the liquid in the liquid phase pipeline 18, providing basic data on the changes in the water content of the extracted material for the control device 16.

[0038] Preferably, the injection well monitoring device in this embodiment includes: Water injection control valve 5 is arranged on water injection pipeline 11 to control the fluid flow on water injection pipeline 11 and adjust the water injection volume according to the instructions of control device 16. The water injection pressure detector 8 is installed on the water injection pipeline 11 to monitor the pressure change of the liquid in the water injection pipeline 11 and transmit the data to the control device 16. Carbon injection control valve 6 is arranged on carbon injection pipeline 12 to control the injection of carbon dioxide and is opened and closed according to the signal of control device 16. Carbon injection pressure detector 9 is installed on carbon injection pipeline 12; it detects the pressure change of gas in carbon injection pipeline 12 and transmits it to control device 16 in real time.

[0039] Example 2: like Figure 2 As shown, this is a gas-water alternating injection method based on carbon dioxide extraction in an embodiment of the present invention. The gas-water alternating injection method is based on the gas-water alternating injection device described in Embodiment 1. The gas-water alternating injection method based on carbon dioxide extraction includes the following steps: S1, the control device 16 collects the parameters of the production well 13 and the injection well 14 obtained in real time by the production well monitoring device and the injection well monitoring device; S2, the control device 16 receives a signal that gas leakage has occurred in the production well 13, sends a signal to the production well monitoring device to close the production well 13, and at the same time sends a signal to the injection well monitoring device to initiate water injection slug. S3, the control device 16 calculates the maximum water injection capacity and controls the injection well monitoring device to inject water into the injection well 14 at a certain flow rate; S4, after the set water injection volume is reached, the control device 16 sends a signal to the injection well monitoring device to stop water injection and resume carbon injection.

[0040] S5. After gas leakage is effectively controlled, the control device 16 sends a signal to the production well monitoring device to reopen the production well 13.

[0041] Preferably, in this embodiment, the control device 16 calculates the maximum water injection capacity in the following way: S301, the carbon injection pipeline pressure data is obtained through the injection well monitoring device, and the reservoir injection pressure is calculated.

[0042] Where Pinjection is the reservoir injection pressure, Py is the pressure data monitored by the carbon injection pressure detector 9, ρ(CO2) is the density of carbon dioxide, g is the gravitational acceleration, and h is the reservoir injection depth. Pressure data and product water cut of production well 13 were obtained through the production well monitoring device. The bottom hole flowing pressure of the production well was calculated by combining the production wellbore gradient.

[0043]

[0044] Wherein, Pflow is the bottom flow pressure of the production well, Pd is the pressure data monitored by the production pressure detector 4, ρ(mixture) is the density of the mixture, ρw is the density of water, fw is the water cut, and ρo is the density of oil.

[0045] S302, calculate the dynamic seepage capacity;

[0046]

[0047] Where Δ is the dynamic seepage capacity, qw is the water production, Kw is the water phase permeability, h is the formation thickness, B is the volume coefficient, μ is the fluid viscosity, re is the supply radius, and rw is the well radius. S303, the maximum injection pressure at the bottom of the well is calculated based on the maximum injection pressure of the injection pump.

[0048] The injection pressure differential was calculated using the maximum injection pressure at the bottom of the well.

[0049] The maximum injection capacity is calculated using injection pressure differential and dynamic seepage capacity.

[0050] Where p_water is the maximum injection pressure at the bottom of the well, p_ppump is the maximum injection pressure of the injection pump, ρ(water) is the density of water, g is the acceleration due to gravity, h is the depth at the bottom of the well, and q_injection is the maximum injection capacity.

[0051] Preferably, in this embodiment, the control device 16 determines the sampling frequency of the flow rate and carbon dioxide content parameters of the extraction well 13 by the changes in the water content and flow rate of the extracted material from the extraction well 13.

[0052] Preferably, in this embodiment, if the change in moisture content is less than 5% or the change in flow rate is less than 20%, the flow rate and carbon dioxide content values ​​are recorded every 3 days.

[0053] Preferably, in this embodiment, if the water content change is greater than 5% or the flow rate change is greater than 20%, the flow rate and carbon dioxide content values ​​are recorded every 3 hours. Preferably, in this embodiment, when the production well monitoring device detects that the carbon dioxide content in the produced material of production well 13 is greater than 20%, it sends a gas leakage signal from production well 13 to control device 16.

[0054] Example 3: This embodiment provides a usage scenario for the gas-water alternating injection device and method based on carbon dioxide extraction described in the above embodiments.

[0055] First, the gas-water alternating injection system is deployed. Production well monitoring devices and injection well monitoring devices are deployed in production well 13 and injection well 14 of the oilfield, respectively. These devices are connected to control device 16. The production well monitoring device includes a carbon dioxide gas detector 1, a flow meter 2, a water cut detector 3, and a production pressure detector 4, used to monitor the fluid state of the production well in real time. The injection well monitoring device includes a water injection control valve 5, a water injection pressure detector 8, a carbon injection control valve 6, and a carbon injection pressure detector 9, used to control and monitor the operation of the injection well. Control device 16 collects real-time parameter values ​​from the production well monitoring device and the injection well monitoring device to detect the status of production well 13 and injection well 14.

[0056] The control device 16 monitors the water cut and flow rate of the production well in real time via the flow meter 2 and the water cut detector 3. If the recorded data shows a water cut change of less than 5% or a flow rate change of less than 20%, the flow rate and carbon dioxide content values ​​are recorded every 3 days to alleviate the pressure on the control device 16 for calculation and storage. If the water cut change exceeds 5% or the flow rate change exceeds 20%, it indicates that the production well has begun to gradually fail, so the data recording frequency of the production well is increased to record the flow rate and carbon dioxide content values ​​every 3 hours.

[0057] When the carbon dioxide gas detector 1 detects that the carbon dioxide content in the produced material is greater than 20%, it indicates that gas channeling has occurred. At this time, the control device 16 receives the gas channeling signal from the carbon dioxide gas detector 1 and sends a valve closing signal to the production control valve 7 and the carbon injection control valve 6 to stop the carbon injection and production operations and prevent further carbon dioxide leakage. Simultaneously, the control device 16 sends a valve opening signal to the water injection control valve 5 to start injecting water into the well.

[0058] The purpose of injecting water into the well is to prevent gas channeling. Therefore, water should be injected at maximum flow rate to ensure that the injected water enters rapidly along the high-permeability zone, achieving the goal of increasing resistance and preventing gas channeling. Since carbon dioxide in the reservoir forms carbonic acid, it has a modifying effect on the reservoir, thus changing the reservoir's permeability, formation flow capacity, and water absorption capacity. Consequently, the maximum water injection capacity also changes, requiring quantitative and dynamic calculation. Because carbon dioxide and crude oil are miscible in some reservoirs, the reservoir still maintains both oil and water phases. After gas channeling, the oil and gas production of well 13 will change significantly, while the water production will not change significantly due to carbon dioxide. Therefore, the water production is used to back-calculate the water phase flow capacity. Based on the calculated dynamic flow capacity, the maximum water injection capacity is determined, and the opening and closing degree of the water injection control valve 5 is then controlled.

[0059] Once the injection well 14 reaches the required water injection volume, the water injection control valve 5 is closed, and the carbon injection control valve 6 is reopened to continue carbon injection-driven oil recovery. After the production well 13 is shut in for three months, it is generally considered that gas channeling has been effectively controlled. The control device 16 automatically opens the production control valve 7, and the production well continues production.

[0060] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas-water alternating injection device based on carbon dioxide extraction, characterized in that, It includes a production well monitoring device, an injection well monitoring device, and a control device (16), wherein the control device (16) is connected to the production well monitoring device and the injection well monitoring device respectively; The well monitoring device is arranged in the well (13) and on the pipeline connected to the well (13); The injection well monitoring device is arranged on the injection well (14) and the water injection pipeline (11) and carbon injection pipeline (12) connected to the injection well (14).

2. The gas-water alternating injection device based on carbon dioxide extraction according to claim 1, characterized in that, The production well (13) is connected to a separator (15) via a pipeline. The separator (15) is connected to one end of a gas phase pipeline (17) and one end of a liquid phase pipeline (18). The other ends of the gas phase pipeline (17) and the liquid phase pipeline (18) are respectively connected to the oil pipeline (10).

3. A gas-water alternating injection device based on carbon dioxide extraction according to claim 2, characterized in that, The production well monitoring device includes: The pressure detector (4) is installed on the pipeline connecting the separator (15) to the well (13); The production control valve (7) is located on the pipeline connecting the production well (13) to the separator (15); A carbon dioxide gas detector (1) is installed on the gas phase pipeline (17); A flow meter (2) is installed on the liquid phase pipeline (18); A water content detector (3) is placed on the liquid phase pipeline (18).

4. The gas-water alternating injection device based on carbon dioxide extraction according to claim 1, characterized in that, The injection well monitoring device includes: Water injection control valve (5) is arranged on water injection pipeline (11); The water injection pressure detector (8) is installed on the water injection pipeline (11); Carbon injection control valve (6) is arranged on carbon injection pipeline (12); The carbon injection pressure detector (9) is placed on the carbon injection pipeline (12).

5. A gas-water alternating injection method based on carbon dioxide extraction, characterized in that, The gas-water alternating injection device based on carbon dioxide extraction is used as described in any one of claims 1 to 4; the gas-water alternating injection method based on carbon dioxide extraction includes the following steps: S1, the control device (16) collects the parameters of the production well (13) and the injection well (14) obtained in real time by the production well monitoring device and the injection well monitoring device; S2, the control device (16) receives a signal that gas leakage has occurred in the production well (13), sends a signal to the production well monitoring device to close the production well (13), and at the same time sends a signal to the injection well monitoring device to initiate water injection slug. S3, the control device (16) calculates the maximum water injection capacity and controls the injection well monitoring device to inject water into the injection well (14) at a certain flow rate; S4, after the set water injection volume is reached, the control device (16) sends a signal to the injection well monitoring device to stop water injection and resume carbon injection; S5. After gas leakage is effectively controlled, the control device (16) sends a signal to the well monitoring device to reopen the well (13).

6. The gas-water alternating injection method based on carbon dioxide extraction according to claim 5, characterized in that, The control device (16) calculates the maximum water injection capacity in the following way: S301, the carbon injection pipeline pressure data is obtained through the injection well monitoring device, and the reservoir injection pressure is calculated. in, Py is the pressure data monitored by the carbon injection pressure detector (9), ρ(CO2) is the density of carbon dioxide, g is the gravitational acceleration, and h is the reservoir injection depth. The pressure data and product water cut of the production well (13) are obtained through the production well monitoring device, and the bottom flow pressure of the production well is calculated by combining the production wellbore gradient. Wherein, P_flow is the bottom flow pressure of the production well, P_d is the pressure data monitored by the production pressure detector (4), ρ(mixture) is the density of the mixture, ρ_w is the density of water, f_w is the water cut, and ρ_o is the density of oil. S302, calculate the dynamic seepage capacity. Where Δ is the dynamic seepage capacity, qw is the water production, Kw is the water phase permeability, h is the formation thickness, B is the volume coefficient, μ is the fluid viscosity, re is the supply radius, and rw is the well radius. S303, the maximum injection pressure at the bottom of the well is calculated based on the maximum injection pressure of the injection pump. The injection pressure differential was calculated using the maximum injection pressure at the bottom of the well. The maximum injection capacity is calculated using injection pressure differential and dynamic seepage capacity. Where p_water is the maximum injection pressure at the bottom of the well, p_ppump is the maximum injection pressure of the injection pump, ρ(water) is the density of water, g is the acceleration due to gravity, h is the depth at the bottom of the well, and q_injection is the maximum injection capacity.

7. A gas-water alternating injection method based on carbon dioxide extraction according to claim 5, characterized in that, The control device (16) determines the flow rate and carbon dioxide content parameter acquisition frequency of the well (13) by the changes in water content and flow rate of the extracted material from the well (13).

8. A gas-water alternating injection method based on carbon dioxide extraction according to claim 7, characterized in that, If the change in moisture content is less than 5% or the change in flow rate is less than 20%, the flow rate and carbon dioxide content values ​​should be recorded every 3 days.

9. A gas-water alternating injection method based on carbon dioxide extraction according to claim 7, characterized in that, If the water content changes by more than 5% or the flow rate changes by more than 20%, the flow rate and carbon dioxide content values ​​will be recorded every 3 hours.

10. A gas-water alternating injection method based on carbon dioxide extraction according to claim 5, characterized in that, When the well monitoring device detects that the carbon dioxide content in the produced material of well (13) is greater than 20%, it sends a gas leakage signal from well (13) to the control device (16).

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