Produced gas processing device and system in core flooding experiment

Abstract

The present invention provides a produced gas processing device and system in a core displacement experiment, which belongs to the field of indoor physical simulation experiment technology. The device includes: a first absorption bottle, a first indicator bottle and a methane collection device connected in sequence, the first absorption bottle is used to absorb carbon dioxide in the produced gas, and the first indicator bottle is used to indicate whether the produced gas output by the first absorption bottle contains carbon dioxide. A circulating absorption tube is provided between the first absorption bottle and the first indicator bottle, the air inlet of the circulating absorption tube is provided above the liquid level of the first indicator bottle, and the air outlet of the circulating absorption tube extends below the liquid level of the first absorption bottle. A first valve is provided on the circulating absorption tube, and a second valve is provided on the air outlet pipe of the first indicator bottle. The produced gas processing device in a core displacement experiment provided by the present invention can effectively separate and collect produced gas, eliminate safety hazards existing in the experimental process, and reduce environmental pollution.

Description

Technical Field

[0001] The present invention relates to the technical field of indoor physical simulation experiments, and in particular to a produced gas processing device in a core displacement experiment and a produced gas processing system in a core displacement experiment. Background Art

[0002] Research on the capture, utilization, and storage of carbon dioxide is also gaining increasing attention. In the oil and gas extraction sector, CO2 injection to enhance oil and gas recovery and geological storage is a new development trend. In laboratory physical simulations, core flooding experiments are often used to evaluate the effectiveness of CO2 injection in enhancing oil and gas reservoir recovery. The application of CO2 injection-enhanced oil and gas recovery technology is also shifting from conventional medium- and high-permeability reservoirs to low-permeability and tight reservoirs. In laboratory CO2 injection flooding experiments, the produced gas composition is relatively simple, primarily consisting of methane and CO2.

[0003] In the existing technology, during indoor simulation experiments, due to the relatively small amount of gas produced, the produced gas is usually discharged directly into the atmosphere, which does not meet environmental protection requirements and cannot separate carbon dioxide and methane. Methane is a flammable and explosive gas, posing a safety hazard of explosion or combustion. Summary of the Invention

[0004] In response to existing technologies that directly discharge produced gas into the atmosphere, polluting the environment and posing safety risks of explosion or combustion, and failing to separate carbon dioxide and methane, the present invention provides a produced gas processing device and a produced gas processing system for core flooding experiments. This method can effectively separate and collect produced gas, eliminating safety risks during the experiment and reducing environmental pollution.

[0005] To achieve the above-mentioned objectives, the first aspect of the present invention provides a produced gas processing device in a core displacement experiment, comprising: a first absorption bottle, a first indicator bottle and a methane collection device connected in sequence, the first absorption bottle containing a carbon dioxide absorbent for absorbing carbon dioxide in the produced gas, the first indicator bottle containing a carbon dioxide indicator for indicating whether the produced gas output by the first absorption bottle contains carbon dioxide; a circulating absorption tube, arranged between the first absorption bottle and the first indicator bottle, the air inlet of the circulating absorption tube being arranged above the liquid level of the first indicator bottle, and the air outlet of the circulating absorption tube extending below the liquid level of the first absorption bottle; a first valve, arranged on the circulating absorption tube, for conducting when the produced gas output by the first absorption bottle contains carbon dioxide, and for shutting off when the produced gas output by the first absorption bottle does not contain carbon dioxide; a second valve, arranged on the air outlet pipe of the first indicator bottle, for shutting off when the produced gas output by the first absorption bottle contains carbon dioxide, and for conducting when the produced gas output by the first absorption bottle does not contain carbon dioxide.

[0006] Furthermore, the produced gas processing device in the core displacement experiment also includes: an image acquisition device, used to acquire the first indicator image of the first indicator bottle and send the first indicator image to the control device; a control device, which is communicatively connected to the image acquisition device, the first valve and the second valve, and is used to determine whether the produced gas output by the first absorption bottle contains carbon dioxide based on the received first indicator image; when the produced gas output by the first absorption bottle contains carbon dioxide, the first valve is controlled to be turned on and the second valve is controlled to be turned off, so as to circulate the produced gas from the first indicator bottle to the first absorption bottle, so that the first absorption bottle circulates and absorbs the carbon dioxide in the produced gas; when the produced gas output by the first absorption bottle does not contain carbon dioxide, the first valve is controlled to be turned off and the second valve is controlled to be turned on, so as to output the produced gas from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0007] Furthermore, the produced gas processing device in the core displacement experiment also includes: a second indicator bottle, arranged between the first indicator bottle and the methane collection device, the second indicator bottle containing a carbon dioxide indicator for indicating whether the produced gas output by the first indicator bottle contains carbon dioxide; a third valve, arranged on the gas outlet pipe of the second indicator bottle; the image acquisition device is also used to acquire a second indicator image of the second indicator bottle and send the second indicator image to the control device; the control device is connected to the third valve and is also used to determine whether the produced gas output by the first indicator bottle contains carbon dioxide based on the received second indicator image; when the produced gas output by the first indicator bottle does not contain carbon dioxide, the third valve is controlled to be turned on to output the produced gas from the second indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0008] Furthermore, the produced gas processing device in the core displacement experiment also includes: a second absorption bottle, which is arranged at the air inlet of the air inlet pipe of the first absorption bottle, and the second absorption bottle is filled with carbon dioxide absorbent, which is used to absorb at least part of the carbon dioxide in the produced gas and output the produced gas to the first absorption bottle.

[0009] Furthermore, the produced gas processing device in the core displacement experiment also includes: a porous air inlet sheet, which is respectively arranged at the air outlet of the air inlet pipe of the first absorption bottle and the second absorption bottle, and the configuration of the porous air inlet sheet matches the configuration of the cross section of the air inlet pipe of the first absorption bottle and the second absorption bottle. A plurality of air inlet holes are evenly distributed on the porous air inlet sheet, which is used to increase the contact area between the produced gas and the carbon dioxide absorbent.

[0010] Furthermore, the pore size of the porous sheet is between 10.0-50.0 μm.

[0011] Furthermore, the methane collection device includes: a water tank; a collecting bottle arranged above the water tank, the collecting bottle is a sealed cavity structure with an air inlet and a water outlet at the bottom, water is sealed in the collecting bottle, and the air outlet pipe of the second indicator bottle is connected to the air inlet of the collecting bottle.

[0012] Furthermore, the first absorption bottle and the second absorption bottle are made of alkali-resistant polypropylene material.

[0013] Furthermore, the carbon dioxide absorbent contained in the second absorption bottle includes sodium hydroxide or potassium hydroxide.

[0014] A second aspect of the present invention provides a system for processing produced gas in a core flooding experiment, comprising the above-mentioned device for processing produced gas in a core flooding experiment.

[0015] The technical solution provided by the present invention has at least the following technical effects:

[0016] The produced gas processing device for core flooding experiments of the present invention comprises a first absorption bottle, a first indicator bottle, and a methane collection device, which are sequentially connected. The first absorption bottle is used to absorb carbon dioxide from the produced gas, and the first indicator bottle is used to indicate whether the produced gas output from the first absorption bottle contains carbon dioxide. A circulating absorption tube is disposed between the first absorption bottle and the first indicator bottle. The gas inlet of the circulating absorption tube is disposed above the liquid level of the first indicator bottle, and the gas outlet of the circulating absorption tube extends below the liquid level of the first absorption bottle. A first valve is disposed on the circulating absorption tube, and a second valve is disposed on the gas outlet pipe of the first indicator bottle. If the produced gas output from the first absorption bottle contains carbon dioxide, the first valve is opened and the second valve is closed to circulate the produced gas from the first indicator bottle to the first absorption bottle, allowing the first absorption bottle to absorb the carbon dioxide in the produced gas. If the produced gas output from the first absorption bottle does not contain carbon dioxide, the first valve is closed and the second valve is opened to output the produced gas from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas. The produced gas processing device in the core flooding experiment provided by the present invention can effectively separate and collect the produced gas, eliminate potential safety hazards in the experimental process, and reduce environmental pollution.

[0017] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following detailed description, they are used to explain the embodiments of the present invention, but do not constitute a limitation of the embodiments of the present invention. In the accompanying drawings:

[0019] Figure 1 A schematic diagram of a produced gas processing device in a core flooding experiment provided by an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of a produced gas processing device in a core flooding experiment provided by another embodiment of the present invention. DETAILED DESCRIPTION

[0021] The following describes the specific implementation of the embodiment of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the embodiment of the present invention and is not used to limit the embodiment of the present invention.

[0022] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0023] In the present invention, unless otherwise specified, directional words such as "up, down, top, bottom" are usually used to describe the relative positions of components in the directions shown in the drawings or in the vertical, perpendicular or gravity directions.

[0024] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0025] Please refer to Figure 1 According to a first aspect of an embodiment of the present invention, there is provided a produced gas processing device in a core displacement experiment, the method comprising the following steps: a first absorption bottle, a first indicator bottle and a methane collection device connected in sequence, the first absorption bottle containing a carbon dioxide absorbent for absorbing carbon dioxide in the produced gas, the first indicator bottle containing a carbon dioxide indicator for indicating whether the produced gas outputted from the first absorption bottle contains carbon dioxide; a circulating absorption pipe arranged between the first absorption bottle and the first indicator bottle, the air inlet of the circulating absorption pipe being arranged above the liquid level of the first indicator bottle, and the air outlet of the circulating absorption pipe extending below the liquid level of the first absorption bottle; a first valve arranged on the circulating absorption pipe, for conducting when the produced gas outputted from the first absorption bottle contains carbon dioxide, and for shutting off when the produced gas outputted from the first absorption bottle does not contain carbon dioxide; a second valve arranged on the air outlet pipe of the first indicator bottle, for shutting off when the produced gas outputted from the first absorption bottle contains carbon dioxide, and for conducting when the produced gas outputted from the first absorption bottle does not contain carbon dioxide.

[0026] Specifically, in an embodiment of the present invention, the produced gas processing device in a core flooding experiment includes a first absorption bottle, a first indicator bottle, and a methane collection device, which are sequentially connected. A circulating absorption tube is disposed between the first absorption bottle and the first indicator bottle. The gas inlet of the circulating absorption tube is located above the liquid level in the first indicator bottle, and the gas outlet of the circulating absorption tube extends below the liquid level in the first absorption bottle. The circulating absorption tube is provided with a first valve. The gas outlet pipe of the first indicator bottle is provided with a second valve.

[0027] The first absorption bottle contains a carbon dioxide absorbent. After the produced gas is input into the first absorption bottle, the carbon dioxide absorbent absorbs the carbon dioxide in the produced gas, separating the carbon dioxide and methane in the produced gas before it is input into the first indicator bottle. The first indicator bottle contains a carbon dioxide indicator. If the produced gas does not react completely in the first absorption bottle, some carbon dioxide will react with the carbon dioxide indicator, causing a color change in the first indicator bottle. Therefore, the color of the carbon dioxide indicator can be used to determine whether the produced gas output from the first absorption bottle contains carbon dioxide.

[0028] If the color does not change, it means that the produced gas output by the first absorption bottle does not contain carbon dioxide. The first valve is closed and the second valve is opened, and the produced gas is output from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas. If the color changes, it means that the produced gas output by the first absorption bottle contains carbon dioxide. The second valve is closed and the first valve is opened, and the produced gas is circulated from the first indicator bottle to the first absorption bottle, so that the first absorption bottle circulates and absorbs the carbon dioxide in the produced gas. After the produced gas circulates and ventilates between the first absorption bottle and the first indicator bottle through the circulation absorption tube for a period of time, the color of the carbon dioxide indicator no longer changes, and the carbon dioxide in the produced gas is completely absorbed. The first valve is closed and the second valve is opened, and the produced gas from which carbon dioxide has been removed is output from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0029] The produced gas processing device in the core flooding experiment provided by the present invention can effectively separate carbon dioxide and methane in the produced gas, collect the separated methane, eliminate safety hazards in the experimental process, and reduce environmental pollution.

[0030] Furthermore, the carbon dioxide indicator includes calcium hydroxide or bromothymol blue. Calcium hydroxide reacts with gas dioxide to form calcium carbonate precipitate, which the carbon dioxide indicator displays as a turbid color. Bromothymol blue is an acid-base indicator. When carbon dioxide is introduced, the solution changes from blue to green and then to yellow.

[0031] Furthermore, the produced gas processing device in the core displacement experiment also includes: an image acquisition device, used to acquire the first indicator image of the first indicator bottle and send the first indicator image to the control device; a control device, which is communicatively connected to the image acquisition device, the first valve and the second valve, and is used to determine whether the produced gas output by the first absorption bottle contains carbon dioxide based on the received first indicator image; when the produced gas output by the first absorption bottle contains carbon dioxide, the first valve is controlled to be turned on and the second valve is controlled to be turned off, so as to circulate the produced gas from the first indicator bottle to the first absorption bottle, so that the first absorption bottle circulates and absorbs the carbon dioxide in the produced gas; when the produced gas output by the first absorption bottle does not contain carbon dioxide, the first valve is controlled to be turned off and the second valve is controlled to be turned on, so as to output the produced gas from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0032] Specifically, in an embodiment of the present invention, the produced gas processing device in a core flooding experiment further includes an image acquisition device and a control device. The image acquisition device is capable of capturing a first indicator image from a first indicator bottle and transmitting the first indicator image to the control device. The control device performs image recognition and image analysis on the received first indicator image to determine whether the solution in the first indicator bottle changes color, thereby determining whether the produced gas output from the first absorption bottle contains carbon dioxide.

[0033] If the color does not change, the produced gas output from the first absorption bottle does not contain carbon dioxide. The control device controls the first valve to close and the second valve to open, and outputs the produced gas from the first indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0034] If the solution changes color, it indicates that the produced gas output from the first absorption bottle contains carbon dioxide. The control device controls the first valve to open and the second valve to close, circulating the produced gas from the first indicator bottle to the first absorption bottle, where the first absorption bottle absorbs the carbon dioxide in the produced gas. After the produced gas circulates between the first absorption bottle and the first indicator bottle through the circulation absorption tube for a period of time, the color of the carbon dioxide indicator no longer changes, indicating that the carbon dioxide in the produced gas has been completely absorbed. The first valve is then controlled to close and the second valve to open, and the produced gas, free of carbon dioxide, is input into the first indicator bottle. The first indicator bottle then outputs the produced gas to the methane collection device to collect the remaining methane in the produced gas.

[0035] The produced gas processing device in the core flooding experiment provided by the present invention can accurately determine whether the produced gas contains carbon dioxide, thereby effectively separating carbon dioxide and methane and improving the separation effect.

[0036] Furthermore, the produced gas processing device in the core displacement experiment also includes: a second indicator bottle, arranged between the first indicator bottle and the methane collection device, the second indicator bottle containing a carbon dioxide indicator for indicating whether the produced gas output by the first indicator bottle contains carbon dioxide; a third valve, arranged on the gas outlet pipe of the second indicator bottle; the image acquisition device is also used to acquire a second indicator image of the second indicator bottle and send the second indicator image to the control device; the control device is connected to the third valve and is also used to determine whether the produced gas output by the first indicator bottle contains carbon dioxide based on the received second indicator image; when the produced gas output by the first indicator bottle does not contain carbon dioxide, the third valve is controlled to be turned on to output the produced gas from the second indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

[0037] Please refer to Figure 2 Specifically, in embodiments of the present invention, if the cycle time is insufficient, incomplete carbon dioxide absorption may occur. The carbon dioxide indicator in the first indicator bottle may have reacted with some carbon dioxide. At this point, determining the presence of carbon dioxide based on the color of the carbon dioxide indicator may be inaccurate. Therefore, a second indicator bottle is positioned between the first indicator bottle and the methane collection device. The second indicator bottle contains a carbon dioxide indicator that indicates whether the produced gas output from the first indicator bottle contains carbon dioxide. After a certain period of cycle time, the control device controls the first valve to close and the second valve to open, transferring the produced gas from the first indicator bottle to the second indicator bottle. An image acquisition device captures an image of the second indicator bottle's second indicator and transmits it to the control device. The control device performs image recognition and analysis on the received second indicator image to determine whether the produced gas output from the first indicator bottle contains carbon dioxide. If the produced gas output from the first indicator bottle does not contain carbon dioxide, the control device controls the third valve to open, transferring the produced gas from the second indicator bottle to the methane collection device to collect the remaining methane in the produced gas. When the produced gas output from the first indicator bottle contains carbon dioxide, the third valve and the second valve are controlled to be closed, and the first valve is controlled to be opened, so that the produced gas continues to be circulated and absorbed in the first absorption bottle.

[0038] The produced gas processing device in the core flooding experiment provided by the present invention can determine whether the produced gas after cyclic absorption contains carbon dioxide, improve the accuracy of carbon dioxide detection, and accurately separate carbon dioxide and methane.

[0039] Furthermore, the produced gas processing device in the core displacement experiment also includes: a second absorption bottle, which is arranged at the air inlet of the air inlet pipe of the first absorption bottle, and the second absorption bottle is filled with carbon dioxide absorbent, which is used to absorb at least part of the carbon dioxide in the produced gas and output the produced gas to the first absorption bottle.

[0040] Specifically, in an embodiment of the present invention, a second absorption bottle is provided at the air inlet of the air inlet pipe of the first absorption bottle. The second absorption bottle contains a carbon dioxide absorbent for absorbing at least part of the carbon dioxide in the produced gas, thereby achieving primary absorption of the carbon dioxide. The produced gas is then output to the first absorption bottle for secondary absorption of the carbon dioxide.

[0041] The produced gas processing device in the core flooding experiment provided by the present invention can process carbon dioxide in stages, improve the absorption effect of carbon dioxide, and thus effectively separate carbon dioxide and methane.

[0042] Furthermore, the carbon dioxide absorbent contained in the second absorption bottle includes sodium hydroxide or potassium hydroxide. Sodium hydroxide or potassium hydroxide can absorb a large amount of carbon dioxide to generate sodium bicarbonate or potassium bicarbonate, thereby achieving primary absorption of carbon dioxide.

[0043] Furthermore, the carbon dioxide absorbent contained in the first absorption bottle includes one or more of sodium hydroxide, potassium hydroxide, diethanolamine and N-methyldiethanolamine solution. The carbon dioxide absorbent in the first absorption bottle can achieve secondary absorption of carbon dioxide.

[0044] Furthermore, the first absorption bottle and the second absorption bottle are made of alkali-resistant polypropylene material.

[0045] Furthermore, the produced gas processing device in the core displacement experiment also includes: a porous air inlet sheet, which is respectively arranged at the air outlet of the air inlet pipe of the first absorption bottle and the second absorption bottle, and the configuration of the porous air inlet sheet matches the configuration of the cross section of the air inlet pipe of the first absorption bottle and the second absorption bottle. A plurality of air inlet holes are evenly distributed on the porous air inlet sheet, which is used to increase the contact area between the produced gas and the carbon dioxide absorbent.

[0046] Specifically, in an embodiment of the present invention, a porous air inlet sheet is provided at the air outlet of the air inlet pipe of the first absorption bottle and the second absorption bottle. The porous air inlet sheet is a sheet-like porous structure, and its configuration matches the configuration of the cross-section of the air inlet pipe of the first absorption bottle and the second absorption bottle. A plurality of air inlet holes are evenly distributed on the porous air inlet sheet. The porous air inlet sheet can allow the produced gas to enter the carbon dioxide absorbent through the plurality of air inlet holes, thereby increasing the contact area between the produced gas and the carbon dioxide absorbent, improving the absorption effect of the carbon dioxide absorbent on carbon dioxide, and shortening the produced gas processing time.

[0047] Furthermore, the pore size of the porous sheet is between 10.0-50.0 μm.

[0048] Furthermore, the methane collection device includes: a water tank; a collecting bottle arranged above the water tank, the collecting bottle is a sealed cavity structure with an air inlet and a water outlet at the bottom, water is sealed in the collecting bottle, and the air outlet pipe of the second indicator bottle is connected to the air inlet of the collecting bottle.

[0049] Specifically, in an embodiment of the present invention, the methane collection device includes a water tank and a collection bottle positioned above the water tank. The collection bottle is a sealed cavity structure with an air inlet and a water outlet at the bottom. Water is sealed within the collection bottle, and the outlet pipe of a second indicator bottle is connected to the air inlet of the collection bottle. Remaining methane in the produced gas enters the collection bottle through the air inlet, discharging a corresponding volume of water through the outlet pipe into the water tank. Furthermore, the outlet pipe of the second indicator bottle extends through the air inlet to the top of the collection bottle, enabling more rapid drainage of water from the collection bottle.

[0050] The produced gas processing device in the core flooding experiment provided by the present invention can realize the sealed collection of methane, prevent methane leakage, and improve the experimental safety of the core flooding experiment.

[0051] Furthermore, in the core flooding experiment, the produced gas processing device's produced gas inlet pipe was equipped with a flow meter and a gas sampling bag. A fourth valve was installed at the gas sampling bag's inlet. Before processing the produced gas, the first valve was closed and the fourth valve was opened, allowing the produced gas to enter the gas sampling bag. After a set period of time, the fourth valve was closed and the first valve was opened. An analysis device determined the total volume of produced gas in the gas sampling bag during the set period based on the flow rate detected by the flow meter. The analysis device then measured the methane concentration in the gas sampling bag to determine the methane production volume during the set period.

[0052] Example 1: Produced gas treatment from a large flat core flooding experiment

[0053] The core used in the experiment measured 10×30×30 cm. The second absorption bottle had a capacity of 2.0 L, containing a 10.0 wt% sodium hydroxide solution as the carbon dioxide absorbent. The first absorption bottle had a capacity of 1.0 L, containing a 5.0 wt% diethanolamine solution as the carbon dioxide absorbent. The first and second indicator bottles contained a 0.3 wt% calcium hydroxide solution as the carbon dioxide indicator. The porous sheet had a pore size of 45.5 μm, and the collection bottle had a capacity of 5.0 L. During the actual indoor simulation experiment, after the carbon dioxide in the produced gas was absorbed by the two-stage absorption bottles, the solution in the indicator bottle showed no precipitation or turbidity, indicating complete absorption of the carbon dioxide.

[0054] Example 2: Produced gas treatment from a 1 m long columnar core flooding experiment

[0055] The core used in the experiment measured 2.5 x 100 cm in diameter. The second absorption bottle had a capacity of 1.0 L, containing an 8.5 wt% sodium hydroxide solution as the carbon dioxide absorbent. The first absorption bottle had a capacity of 1 L, containing a 4.5 wt% diethanolamine solution as the carbon dioxide absorbent. The first and second indicator bottles contained a 0.4 wt% calcium hydroxide solution as the carbon dioxide indicator. The porous sheet had a pore size of 35.5 μm, and the collection bottle had a capacity of 2.5 L. During the actual laboratory simulation, after the carbon dioxide in the produced gas was absorbed by the two-stage absorption bottles, the solution in the indicator bottle showed no precipitation or turbidity, indicating complete absorption of the carbon dioxide.

[0056] Example 3: Produced gas treatment from heterogeneous plate-shaped core flooding experiment

[0057] The core used in the experiment measured 2.5 × 2.5 × 30 cm. The second absorption bottle had a capacity of 0.5 L, and the carbon dioxide absorbent in the second absorption bottle was a 6.0 wt% sodium hydroxide solution. The first absorption bottle had a capacity of 0.5 L, and the carbon dioxide absorbent in the first absorption bottle was a 3.5 wt% diethanolamine solution. The carbon dioxide indicators in the first and second indicator bottles were 0.5 wt% calcium hydroxide solutions. The pore size of the porous sheet was 25.0 μm, and the collection bottle had a capacity of 1.0 L. During the actual indoor simulation experiment, after the carbon dioxide in the produced gas was absorbed by the two-stage absorption bottles, the solution in the indicator bottle showed no precipitation or turbidity, indicating that the carbon dioxide was completely absorbed.

[0058] Example 4: Separation and measurement of produced gas from a short cylindrical core flooding experiment

[0059] The core used in the experiment measured 2.5 x 7.5 cm in diameter. The second absorption bottle had a capacity of 0.5 L and contained a 5.0 wt% sodium hydroxide solution as the carbon dioxide absorbent. The first absorption bottle had a capacity of 0.5 L and contained a 3.0 wt% diethanolamine solution as the carbon dioxide absorbent. The first and second indicator bottles contained a 0.5 wt% calcium hydroxide solution as the carbon dioxide indicator. The porous sheet had a pore size of 15 μm. The collection bottle had a capacity of 0.5 L. During the actual indoor simulation experiment, the carbon dioxide in the produced gas was completely absorbed by the first absorption bottle, and the solution in the indicator bottle showed no precipitation or turbidity, indicating complete absorption of the carbon dioxide.

[0060] A second aspect of the present invention provides a system for processing produced gas in a core flooding experiment, comprising the above-mentioned device for processing produced gas in a core flooding experiment.

[0061] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0062] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0063] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A produced gas processing device in a core flooding experiment, characterized in that: The produced gas processing device in the core flooding experiment includes: A first absorption bottle, a first indicator bottle and a methane collection device connected in sequence, wherein the first absorption bottle contains a carbon dioxide absorbent for absorbing carbon dioxide in the produced gas, and the first indicator bottle contains a carbon dioxide indicator for indicating whether the produced gas outputted from the first absorption bottle contains carbon dioxide; a circulation absorption tube, disposed between the first absorption bottle and the first indicator bottle, wherein the air inlet of the circulation absorption tube is disposed above the liquid level of the first indicator bottle, and the air outlet of the circulation absorption tube extends below the liquid level of the first absorption bottle; a first valve, provided on the circulating absorption pipe, for conducting when the produced gas outputted from the first absorption bottle contains carbon dioxide, and closing when the produced gas outputted from the first absorption bottle does not contain carbon dioxide; The second valve is provided on the gas outlet pipe of the first indicator bottle, and is used to shut off when the produced gas output from the first absorption bottle contains carbon dioxide, and to open when the produced gas output from the first absorption bottle does not contain carbon dioxide.

2. The produced gas processing device in the core flooding experiment according to claim 1, characterized in that: The produced gas processing device in the core flooding experiment also includes: an image acquisition device, configured to acquire a first indicator image of the first indicator bottle and send the first indicator image to a control device; A control device is communicatively connected to the image acquisition device, the first valve, and the second valve, and is used to determine whether the produced gas output by the first absorption bottle contains carbon dioxide based on the received first indicator image; when the produced gas output by the first absorption bottle contains carbon dioxide, the first valve is controlled to be turned on and the second valve is controlled to be turned off, so as to circulate the produced gas from the first indicator bottle to the first absorption bottle, so that the first absorption bottle circulates and absorbs the carbon dioxide in the produced gas; when the produced gas output by the first absorption bottle does not contain carbon dioxide, the first valve is controlled to be turned off and the second valve is controlled to be turned on, so as to output the produced gas from the first indicator bottle to the methane collection device, so as to collect the remaining methane in the produced gas.

3. The produced gas processing device in the core flooding experiment according to claim 2, characterized in that: The produced gas processing device in the core flooding experiment also includes: a second indicator bottle, disposed between the first indicator bottle and the methane collection device, containing a carbon dioxide indicator for indicating whether the produced gas outputted from the first indicator bottle contains carbon dioxide; a third valve, disposed on the air outlet pipe of the second indicator bottle; The image acquisition device is further configured to acquire a second indicator image of the second indicator bottle and send the second indicator image to the control device; The control device is connected to the third valve and is also used to determine whether the produced gas output by the first indicator bottle contains carbon dioxide based on the received second indicator image; when the produced gas output by the first indicator bottle does not contain carbon dioxide, the control device controls the third valve to be turned on to output the produced gas from the second indicator bottle to the methane collection device to collect the remaining methane in the produced gas.

4. The produced gas processing device in the core flooding experiment according to claim 1, characterized in that: The produced gas processing device in the core flooding experiment also includes: The second absorption bottle is arranged at the air inlet of the air inlet pipe of the first absorption bottle. The second absorption bottle contains carbon dioxide absorbent for absorbing at least part of the carbon dioxide in the produced gas and outputting the produced gas to the first absorption bottle.

5. The produced gas processing device in the core flooding experiment according to claim 4, characterized in that: The produced gas processing device in the core flooding experiment also includes: The porous air inlet sheet is respectively arranged at the air outlet of the air inlet pipe of the first absorption bottle and the second absorption bottle. The configuration of the porous air inlet sheet matches the configuration of the cross section of the air inlet pipe of the first absorption bottle and the second absorption bottle. A plurality of air inlet holes are evenly distributed on the porous air inlet sheet to increase the contact area between the produced gas and the carbon dioxide absorbent.

6. The produced gas processing device in the core flooding experiment according to claim 5, characterized in that: The pore size of the porous sheet is between 10.0 and 50.0 μm.

7. The produced gas processing device in the core flooding experiment according to claim 3, characterized in that: The methane collection device comprises: sink; A collecting bottle is arranged above the water tank. The collecting bottle is a sealed cavity structure with an air inlet and a water outlet at the bottom. Water is sealed in the collecting bottle. The air outlet pipe of the second indicator bottle is connected to the air inlet of the collecting bottle.

8. The produced gas processing device in the core flooding experiment according to claim 4, characterized in that: The first absorption bottle and the second absorption bottle are made of alkali-resistant polypropylene material.

9. The produced gas processing device in the core flooding experiment according to claim 4, characterized in that: The carbon dioxide absorbent contained in the second absorption bottle includes sodium hydroxide or potassium hydroxide.

10. A produced gas processing system in a core flooding experiment, characterized in that: A produced gas processing device for a core flooding experiment comprising any one of claims 1 to 9.

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