A Method for Evaluating the Effectiveness of Carbon Dioxide Sealing in the Roof of Different Types of Coal Seams

Abstract

A method for evaluating the effectiveness of carbon dioxide sequestration in different types of coal seams includes the following steps: 1. Assembling an experimental system for evaluating the effectiveness of carbon dioxide sequestration in different types of coal seams, comprising a coal seam roof simulation system, a carbon dioxide injection system, and a sequestration monitoring and evaluation system; 2. Creating a coal seam roof using the coal seam roof simulation system and simulating real coal seam pressure; 3. Injecting carbon dioxide into the coal seam using the carbon dioxide injection system; 4. Monitoring and recording the pressure at different locations on the coal seam roof using the sequestration monitoring and evaluation system to evaluate the effectiveness of carbon dioxide sequestration; 5. Changing the coal seam roof type, coal seam pressure, and carbon dioxide injection pressure, and then evaluating the carbon dioxide sequestration effect again. This invention can simulate real coal seams and different types of coal seam roofs, enabling the evaluation of the effectiveness of carbon dioxide sequestration in different types of coal seams, reducing investment risk, and providing a basis for on-site carbon dioxide coal seam sequestration.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide geological storage technology, specifically to a method for evaluating the effectiveness of carbon dioxide storage in the roof of different types of coal seams. Background Technology

[0002] With global economic development and continuous improvement in industrialization, the consumption of fossil energy (coal, oil, natural gas, etc.) has grown rapidly, leading to large-scale emissions of greenhouse gases, primarily carbon dioxide, resulting in continuous global warming over the past 100 years. Reducing atmospheric carbon dioxide concentration through carbon dioxide storage is an effective means of mitigating the global greenhouse effect. Carbon dioxide storage technologies can be broadly categorized into geological storage, biological storage, marine storage, mineral storage (ore carbonization), and industrial utilization. Geological storage is the most effective and economical permanent carbon dioxide storage technology, including storage in depleted oil and gas reservoirs, enhanced oil recovery through carbon dioxide injection, deep saline aquifer storage, and deep coal seam sequestration (CO2-ECBM) for enhanced coalbed methane extraction.

[0003] Coal-sea carbon dioxide geological storage and methane-enhanced development (CO2-ECBM) technology can improve methane recovery in coal seams while also effectively storing the greenhouse gas CO2. However, due to the potential leakage risk associated with CO2 storage in coal seams, the effectiveness of different types of roof-based CO2 storage needs to be evaluated.

[0004] The lack of objective evaluation regarding which types of coal seam roof sealing are effective and which are ineffective has led to blind spots in engineering projects and increased investment risks, thus limiting the on-site promotion and application of carbon dioxide coal seam sealing to some extent.

[0005] How to evaluate the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams has become a widely concerned topic. Currently, there is an urgent need for a method to evaluate the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams, enabling efficient and accurate evaluation and providing a theoretical basis for on-site carbon dioxide sequestration in coal seams. Summary of the Invention

[0006] The purpose of this invention is to provide a method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams. This invention can simulate real coal seams and roofs of different types of coal seams, enabling the evaluation of the effectiveness of carbon dioxide sequestration in the roofs of different types of coal seams, reducing investment risks, and providing a basis for on-site carbon dioxide sequestration in coal seams.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams includes the following steps:

[0009] I. Assemble an experimental system for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams, which includes a coal seam roof simulation system, a carbon dioxide injection system, and a sequestration monitoring and evaluation system;

[0010] 2. Based on the actual coal seam roof type, a coal seam roof simulation system is used to create the coal seam roof and simulate the actual coal seam pressure.

[0011] 3. Inject carbon dioxide into the coal seam through a carbon dioxide injection system until the design pressure is reached;

[0012] IV. The pressure at different locations on the roof of the coal seam is monitored and recorded through the sealing monitoring and evaluation system. The effect of sealing carbon dioxide on the roof of the coal seam is evaluated based on the recorded pressure data.

[0013] Fifth, by changing the type of coal seam roof, coal seam pressure, and carbon dioxide injection pressure, different coal seam roof conditions are simulated, and then the carbon dioxide sequestration effect is evaluated through a sequestration monitoring and evaluation system.

[0014] The coal seam roof simulation system includes a housing, a temperature controller, a water tank, and a water injection pump. The housing is made of tempered glass and has an open front. A tempered sliding door slides left and right on the front of the housing. The inner wall of the housing is equipped with an electric heating interlayer. The temperature controller is located outside the housing and is connected to the electric heating interlayer. The interior of the housing is laid from bottom to top as follows: coal seam floor, coal seam, several layers of different types of coal seam roof, steel plate, and pressure bladder. The water tank and water injection pump are both located outside the housing. The outlet of the water tank is connected to the inlet of the water injection pump through an outlet pipe. The outlet of the water injection pump is connected to an injection pipe. The outlet of the injection pipe passes through the upper part of the side plate of the housing and extends into the housing. The outlet of the injection pipe is connected to the inlet of the pressure bladder.

[0015] The carbon dioxide injection system includes a carbon dioxide cylinder. The top outlet of the carbon dioxide cylinder is connected to an injection pipe. An injection valve, a carbon dioxide delivery pump, and a first pressure sensor are sequentially installed on the injection pipe along the gas flow direction. The outlet of the injection pipe passes vertically downward through the top plate of the box, the pressurized bag, and the top plate of each coal seam and is inserted into the coal seam.

[0016] The sealing monitoring and evaluation system includes a computer and several rows of second pressure sensors. Each row of second pressure sensors is installed vertically and vertically in the roof of each coal seam. The distances between each row of second pressure sensors and the top surface of the coal seam are x, 3x, and 5x, respectively. Each row of second pressure sensors includes three second pressure sensors, which are evenly spaced horizontally in the corresponding coal seam roof. The computer is connected to the first pressure sensor and each of the second pressure sensors.

[0017] Step (II) is as follows: Open the tempered sliding door, and according to the actual coal seam roof type and similarity ratio, lay the coal seam floor, coal seam, each layer of coal seam roof, steel plate and pressure bag in the box from bottom to top. During the laying process, install the second pressure sensor of each row in the roof of each different type of coal seam at intervals. Then, vertically pass the outlet end of the gas injection pipe through the roof of the box, the pressure bag and each layer of coal seam roof and insert it into the coal seam. Then close the tempered sliding door and seal the front opening of the box. Then start the water injection pump. The water injection pump injects water from the water tank into the pressure bag through the water injection pipe, so that the pressure bag applies downward pressure to simulate the pressure of the real coal seam and form a complete experimental system.

[0018] Step (3) is as follows: Open the gas injection valve, start the carbon dioxide delivery pump, and inject the carbon dioxide gas in the carbon dioxide cylinder into the coal seam through the gas injection pipe. The pressure in the gas injection pipe is monitored in real time by the first pressure sensor. When the pressure in the gas injection pipe reaches the design pressure, close the gas injection valve and the carbon dioxide delivery pump to stop injecting carbon dioxide.

[0019] Step (iv) is as follows: Each row of second pressure sensors monitors the gas pressure in the roof of each coal seam and transmits the monitored pressure data to the computer. The pressure data monitored by the first row of second pressure sensors are X1, X2, and X3, so the gas pressure record in the roof of the first coal seam is (X1+X2+X3) / 3; the pressure data monitored by the second row of second pressure sensors are X4, X5, and X6, so the gas pressure record in the roof of the second coal seam is (X4+X5+X6) / 3; the pressure data monitored by the third row of second pressure sensors are X7, X8, and X9, so the gas pressure record in the roof of the third coal seam is (X7+X8+X9) / 3. The gas pressure record in the roof of each coal seam is obtained through the monitoring of the corresponding row of second pressure sensors. Based on the recorded pressure data, the effect of carbon dioxide sealing in the coal seam roof is evaluated.

[0020] This invention has outstanding substantive features and significant progress compared with the prior art. Specifically, this invention can simulate real coal seams and different types of coal seam roofs, realize the evaluation of the carbon dioxide sealing effect of different types of coal seam roofs, reduce investment risks, and provide a basis for on-site carbon dioxide coal seam sealing.

[0021] The enclosure is made of tempered glass, which can withstand a certain amount of pressure and allows staff to easily observe the coal seams and the roof of each coal seam inside the enclosure. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the experimental system of the present invention.

[0023] Figure 2 This is a schematic diagram of the coal seam roof simulation system of the present invention.

[0024] Figure 3 This is a distribution diagram of the second pressure sensors of each row in the roof of each coal seam according to the present invention. Detailed Implementation

[0025] The embodiments of the present invention are further described below with reference to the accompanying drawings.

[0026] like Figure 1-3 As shown, a method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams includes the following steps:

[0027] I. Assemble an experimental system for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams, which includes a coal seam roof simulation system, a carbon dioxide injection system, and a sequestration monitoring and evaluation system;

[0028] 2. Based on the actual coal seam roof type, coal seam roof 1 is created using a coal seam roof simulation system, and the actual coal seam pressure is simulated.

[0029] 3. Inject carbon dioxide into the coal seam through a carbon dioxide injection system until the design pressure is reached;

[0030] IV. The pressure at different locations of the coal seam roof 1 is monitored and recorded through the sealing monitoring and evaluation system. The effect of sealing carbon dioxide in the coal seam roof 1 is evaluated based on the recorded pressure data.

[0031] 5. By changing the type of coal seam roof, coal seam pressure, and carbon dioxide injection pressure, different coal seam roof conditions are simulated, and the carbon dioxide sequestration effect is evaluated through a sequestration monitoring and evaluation system.

[0032] The coal seam roof simulation system includes a housing 2, a temperature controller 3, a water tank 4, and a water injection pump 5. The housing 2 is made of tempered glass and has an open front. A tempered sliding door 6 is installed on the front opening of the housing 2. The inner wall of the housing 2 is equipped with an electric heating interlayer (not shown in the figure). The temperature controller 3 is located outside the housing 2 and is connected to the electric heating interlayer. The interior of the housing 2 is laid from bottom to top with a coal seam floor 7, a coal seam 8, three different types of coal seam roof 1, a steel plate 9, and a pressure bag 10. The water tank 4 and the water injection pump 5 are both located outside the housing 2. The water outlet of the water tank 4 is connected to the water inlet of the water injection pump 5 through a water outlet pipe 11. The water outlet of the water injection pump 5 is connected to a water injection pipe 12. The water outlet of the water injection pipe 12 passes through the upper part of the side plate of the housing 2 and extends into the housing 2. The water outlet of the water injection pipe 12 is connected to the water inlet of the pressure bag 10.

[0033] The carbon dioxide injection system includes a carbon dioxide cylinder 13. The top outlet of the carbon dioxide cylinder 13 is connected to an injection pipe 14. An injection valve 15, a carbon dioxide delivery pump 16, and a first pressure sensor 17 are sequentially arranged on the injection pipe 14 along the gas flow direction. The outlet of the injection pipe 14 passes vertically downward through the top plate of the box 2, the pressurized bag 10, and the top plate 1 of each coal seam and is inserted into the coal seam 8.

[0034] The sealing monitoring and evaluation system includes a computer 18 and three rows of second pressure sensors 19. Each row of second pressure sensors 19 is installed vertically and vertically in the roof of each coal seam 8. The distances between each row of second pressure sensors 19 and the top surface of the coal seam 8 are x, 3x, and 5x, respectively. Each row of second pressure sensors 19 includes three second pressure sensors 19. The three second pressure sensors 19 are evenly spaced horizontally in the corresponding coal seam roof 1. The computer 18 is connected to the first pressure sensor 17 and each of the second pressure sensors 19.

[0035] Step (II) is as follows: Open the tempered sliding door 6. According to the actual coal seam roof type and similarity ratio, lay the coal seam floor 7, coal seam 8, each coal seam roof 1, steel plate 9, and pressure bag 10 in the box 2 from bottom to top. During the laying process, install each row of second pressure sensors 19 in the roof 1 of each different type of coal seam at intervals. Then, vertically and downwardly pass the outlet end of the gas injection pipe 14 through the roof 2, pressure bag 10, and each coal seam roof 1 and insert it into the coal seam 8. Then close the tempered sliding door 6 and seal the front opening of the box 2. Then start the water injection pump 5. The water injection pump 5 injects water from the water tank 4 into the pressure bag 10 through the water injection pipe 12, so that the pressure bag 10 applies downward pressure to simulate the actual coal seam pressure and form a complete experimental system.

[0036] Step (3) is as follows: Open the gas injection valve 15, start the carbon dioxide delivery pump 16, and the carbon dioxide delivery pump 16 injects the carbon dioxide gas in the carbon dioxide cylinder 13 into the coal seam 8 through the gas injection pipe 14. The pressure in the gas injection pipe 14 is monitored in real time by the first pressure sensor 17. When the pressure in the gas injection pipe 14 reaches the design pressure, close the gas injection valve 15 and the carbon dioxide delivery pump 16 to stop injecting carbon dioxide.

[0037] Step (iv) is as follows: Each row of second pressure sensors 19 monitors the gas pressure in the roof 1 of each coal seam and transmits the monitored pressure data to the computer 18. The pressure data monitored by the first row of second pressure sensors 19 are X1, X2, and X3, so the gas pressure in the roof 1 of the first coal seam is recorded as (X1+X2+X3) / 3; the pressure data monitored by the second row of second pressure sensors 19 are X4, X5, and X6, so the gas pressure in the roof 1 of the second coal seam is recorded as (X4+X5+X6) / 3; the pressure data monitored by the third row of second pressure sensors 19 are X7, X8, and X9, so the gas pressure in the roof 1 of the third coal seam is recorded as (X7+X8+X9) / 3. The gas pressure records in the roof 1 of each coal seam are obtained through the monitoring of the corresponding rows of second pressure sensors 19. Based on the recorded pressure data, the effect of carbon dioxide sealing in the roof 1 of the coal seam is evaluated.

[0038] This invention can simulate real coal seams and different types of coal seam roofs, enabling the evaluation of carbon dioxide sequestration effects on different types of coal seam roofs, reducing investment risks, and providing a basis for on-site carbon dioxide coal seam sequestration.

[0039] The box 2 is made of tempered glass. Tempered glass can not only withstand a certain amount of pressure, but also allows staff to easily observe the coal seam and the roof of each coal seam inside the box.

[0040] Temperature controller 3, electric heating interlayer, tempered sliding door 6, water injection pump 5, carbon dioxide delivery pump 16, first pressure sensor 17 and second pressure sensor 19 are all conventional technologies, and their specific structures and working principles will not be described in detail.

[0041] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams, characterized in that: Includes the following steps: I. Assemble an experimental system for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams, which includes a coal seam roof simulation system, a carbon dioxide injection system, and a sequestration monitoring and evaluation system; 2. Based on the actual type of coal seam roof, a coal seam roof simulation system is used to create the coal seam roof and simulate the actual coal seam pressure.

3. Inject carbon dioxide into the coal seam through a carbon dioxide injection system until the design pressure is reached; IV. The pressure at different locations on the roof of the coal seam is monitored and recorded through the sealing monitoring and evaluation system. The effect of sealing carbon dioxide on the roof of the coal seam is evaluated based on the recorded pressure data.

5. By changing the type of coal seam roof, coal seam pressure, and carbon dioxide injection pressure, different coal seam roof conditions are simulated, and then the carbon dioxide sequestration effect is evaluated through a sequestration monitoring and evaluation system. The coal seam roof simulation system includes a housing, a temperature controller, a water tank, and a water injection pump. The housing is made of tempered glass and has an open front. A tempered sliding door is installed on the front of the housing. The inner wall of the housing is equipped with an electric heating interlayer. The temperature controller is located outside the housing and is connected to the electric heating interlayer. The interior of the housing is laid from bottom to top with the coal seam floor, coal seam, several layers of different types of coal seam roof, steel plate, and pressure bladder. The water tank and water injection pump are both located outside the housing. The water outlet of the water tank is connected to the water inlet of the water injection pump through a water outlet pipe. The water outlet of the water injection pump is connected to a water injection pipe. The water outlet of the water injection pipe passes through the upper part of the side plate of the housing and extends into the housing. The water outlet of the water injection pipe is connected to the water inlet of the pressure bladder. The carbon dioxide injection system includes a carbon dioxide cylinder. The top outlet of the carbon dioxide cylinder is connected to an injection pipe. An injection valve, a carbon dioxide delivery pump, and a first pressure sensor are sequentially installed on the injection pipe along the gas flow direction. The outlet of the injection pipe passes vertically downward through the top plate of the box, the pressurized bag, and the top plate of each coal seam and is inserted into the coal seam. The sealing monitoring and evaluation system includes a computer and several rows of second pressure sensors. Each row of second pressure sensors is installed vertically and vertically in the roof of each coal seam. The distances between each row of second pressure sensors and the top surface of the coal seam are x, 3x, and 5x, respectively. Each row of second pressure sensors includes three second pressure sensors, which are evenly spaced horizontally in the corresponding coal seam roof. The computer is connected to the first pressure sensor and each of the second pressure sensors.

2. The method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams according to claim 1, characterized in that: Step (II) is as follows: Open the tempered sliding door, and according to the actual coal seam roof type and similarity ratio, lay the coal seam floor, coal seam, each layer of coal seam roof, steel plate and pressure bag in the box from bottom to top. During the laying process, install the second pressure sensor of each row in the roof of each different type of coal seam at intervals. Then, vertically pass the outlet end of the gas injection pipe through the roof of the box, the pressure bag and each layer of coal seam roof and insert it into the coal seam. Then close the tempered sliding door and seal the front opening of the box. Then start the water injection pump. The water injection pump injects water from the water tank into the pressure bag through the water injection pipe, so that the pressure bag applies downward pressure to simulate the pressure of the real coal seam and form a complete experimental system.

3. The method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams according to claim 2, characterized in that: Step (3) is as follows: Open the gas injection valve, start the carbon dioxide delivery pump, and inject the carbon dioxide gas in the carbon dioxide cylinder into the coal seam through the gas injection pipe. The pressure in the gas injection pipe is monitored in real time by the first pressure sensor. When the pressure in the gas injection pipe reaches the design pressure, close the gas injection valve and the carbon dioxide delivery pump to stop injecting carbon dioxide.

4. The method for evaluating the effectiveness of carbon dioxide sequestration in the roof of different types of coal seams according to claim 3, characterized in that: Step (iv) is as follows: Each row of second pressure sensors monitors the gas pressure in the roof of each coal seam and transmits the monitored pressure data to the computer. The pressure data monitored by the first row of second pressure sensors are X1, X2, and X3, so the gas pressure record in the roof of the first coal seam is (X1+X2+X3) / 3; the pressure data monitored by the second row of second pressure sensors are X4, X5, and X6, so the gas pressure record in the roof of the second coal seam is (X4+X5+X6) / 3; the pressure data monitored by the third row of second pressure sensors are X7, X8, and X9, so the gas pressure record in the roof of the third coal seam is (X7+X8+X9) / 3. The gas pressure record in the roof of each coal seam is obtained through the monitoring of the corresponding row of second pressure sensors. Based on the recorded pressure data, the effect of carbon dioxide sealing in the coal seam roof is evaluated.

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