Device and system for treating produced gas in core displacement experiment

Abstract

The invention provides a device and a system for treating produced gas in a core displacement experiment, and belongs to the technical field of indoor physical simulation experiments.The device comprises a first absorption bottle, a first indicator bottle and a methane collecting device which are sequentially communicated, and the first absorption bottle is used for absorbing carbon dioxide in the produced gas; the first indicator bottle is used for indicating whether the produced gas output by the first absorption bottle contains carbon dioxide or not. A circulating absorption tube is arranged between the first absorption bottle and the first indicator bottle, an air inlet of the circulating absorption tube is arranged above the liquid level of the first indicator bottle, and an air outlet of the circulating absorption tube extends below the liquid level of the first absorption bottle. A first valve is arranged on the circulating absorption pipe, and a second valve is arranged on an air outlet pipe of the first indicator bottle. By means of the produced gas treatment device in the rock core displacement experiment, produced gas can be effectively separated and collected, potential safety hazards existing in the experiment process are eliminated, and environmental pollution is reduced.

Description

Technical Field

[0001] The 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] The capture, utilization and storage of carbon dioxide are also receiving more and more attention. In the field of oil and gas extraction, carbon dioxide injection to improve oil recovery and geological storage is a new development trend. In indoor physical simulation experiments, core displacement experiments are often used to evaluate the effect of carbon dioxide injection to improve oil and gas reservoir recovery. The application of carbon dioxide injection to improve oil recovery technology has also shifted from conventional medium and high permeability reservoirs to low permeability and tight oil and gas reservoirs. In indoor carbon dioxide injection displacement experiments, the composition of the produced gas is relatively simple, mainly methane and carbon dioxide.

[0003] In the prior art, 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 and there is a safety hazard of explosion or combustion. Summary of the invention

[0004] In view of the fact that the produced gas in the prior art is directly discharged into the atmosphere, polluting the environment, posing a safety hazard of explosion or combustion, and failing to separate carbon dioxide and methane, the present invention provides a produced gas processing device in a core displacement experiment and a produced gas processing system in a core displacement experiment. The method can effectively separate and collect the produced gas, eliminate the safety hazard in the experimental process, and reduce environmental pollution.

[0005] To achieve the above-mentioned purpose, 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 in communication with 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 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.

[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 a 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.

[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 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 device for processing produced gas in a core flooding experiment as described above.

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

[0016] The produced gas processing device in the core displacement experiment of the present invention comprises a first absorption bottle, a first indicator bottle and a methane collecting device which are connected in sequence, wherein 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 outputted from the first absorption bottle contains carbon dioxide. A circulating absorption tube is arranged between the first absorption bottle and the first indicator bottle, wherein the air inlet of the circulating absorption tube is arranged 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 arranged on the circulating absorption tube, and a second valve is arranged on the air outlet pipe of the first indicator bottle. When the produced gas outputted from the first absorption bottle contains carbon dioxide, the first valve is turned on and the second valve is turned off to circulate the produced gas from the first indicator bottle to the first absorption bottle, so that the first absorption bottle circulates and absorbs carbon dioxide in the produced gas; when the produced gas outputted from the first absorption bottle does not contain carbon dioxide, the first valve is turned off and the second valve is turned on to output the produced gas from the first indicator bottle to the methane collecting device to collect the remaining methane in the produced gas. The produced gas processing device in the core displacement experiment provided by the present invention can effectively separate and collect the produced gas, eliminate the potential safety hazards in the experiment 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 specific implementations, they are used to explain the embodiments of the present invention, but do not constitute a limitation on 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 displacement experiment provided by an embodiment of the present invention;

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

[0021] The specific implementation of the embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here 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 with reference to the directions shown in the drawings or are used to describe the relative positional relationships of components in the vertical, perpendicular or gravity direction.

[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 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 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 the embodiment of the present invention, the produced gas processing device in the core displacement experiment includes a first absorption bottle, a first indicator bottle and a methane collection device which are connected in sequence. A circulating absorption tube is arranged between the first absorption bottle and the first indicator bottle, the air inlet of the circulating absorption tube is arranged above the liquid level of the first indicator bottle, the air outlet of the circulating absorption tube extends below the liquid level of the first absorption bottle, and a first valve is arranged on the circulating absorption tube. A second valve is arranged on the air outlet pipe of the first indicator bottle.

[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, separates the carbon dioxide and methane in the produced gas, and then inputs the produced gas 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, part of the carbon dioxide will react with the carbon dioxide indicator, and a color change will occur in the first indicator bottle. Therefore, it can be judged whether the produced gas output from the first absorption bottle contains carbon dioxide based on the color of the carbon dioxide indicator.

[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 turned on to output the produced gas 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 turned on 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. After the produced gas circulates and ventilates between the first absorption bottle and the first indicator bottle through the circulating 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 turned on to output the produced gas from which carbon dioxide has been removed 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 displacement experiment provided by the present invention can effectively separate carbon dioxide and methane in the produced gas, collect the separated methane, eliminate the potential safety hazards in the experimental process, and reduce environmental pollution.

[0030] Further, the carbon dioxide indicator includes calcium hydroxide or bromothymol blue. Calcium hydroxide can react with natural gas to generate calcium carbonate precipitation, and the carbon dioxide indicator is displayed as a turbid color. Bromothymol blue is an acid-base indicator. When carbon dioxide is input, 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 in communication with 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 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.

[0032] Specifically, in an embodiment of the present invention, the produced gas processing device in the core displacement experiment further includes an image acquisition device and a control device. The image acquisition device can acquire the first indicator image of the first indicator bottle and send 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 by 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, the produced gas output from the first absorption bottle contains carbon dioxide. The control device controls the first valve to be turned on and the second valve to be turned off, and the produced gas is circulated from the first indicator bottle to the first absorption bottle, and the first absorption bottle is used to circulate and absorb 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 controlled to be turned off and the second valve is turned on, and the produced gas with carbon dioxide removed is input into the first indicator bottle, and then the first indicator bottle outputs it to the methane collection device to collect the remaining methane in the produced gas.

[0035] The produced gas processing device in the core displacement 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 the embodiment of the present invention, if the circulation time is insufficient, the carbon dioxide absorption may be incomplete, and the carbon dioxide indicator in the first indicator bottle has reacted with part of the carbon dioxide. At this time, judging whether carbon dioxide is contained according to the color of the carbon dioxide indicator is not accurate enough. Therefore, a second indicator bottle is arranged between the first indicator bottle and the methane collection device, and the second indicator bottle contains a carbon dioxide indicator, which is used to indicate whether the produced gas output by the first indicator bottle contains carbon dioxide. After a period of circulation, the control device controls the first valve to be closed and the second valve to be turned on, so that the produced gas is input from the first indicator bottle to the second indicator bottle. The image acquisition device acquires the second indicator image of the second indicator bottle and sends the second indicator image to the control device. The control device performs image recognition and image analysis on the received second indicator image to judge whether carbon dioxide is contained in the produced gas output by the first indicator bottle. In the case that 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. 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 turned on, 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 displacement 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 a 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.

[0040] Specifically, in an embodiment of the present invention, a second absorption bottle is arranged at the air inlet of the air inlet pipe of the first absorption bottle, and the second absorption bottle is filled with a carbon dioxide absorbent for absorbing at least part of the carbon dioxide in the produced gas to achieve primary absorption of carbon dioxide, and then the produced gas is output to the first absorption bottle for secondary absorption of carbon dioxide.

[0041] The produced gas processing device in the core displacement 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 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 arranged 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 in the collection bottle, and the air outlet pipe of the second indicator bottle is connected to the air inlet of the collection bottle. The remaining methane in the produced gas enters the collection bottle through the air inlet, and the corresponding volume of water is discharged from the air outlet pipe to the water tank. Furthermore, the air outlet pipe of the second indicator bottle extends into the top of the collection bottle through the air inlet, which can discharge the water in the collection bottle more quickly.

[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 displacement experiment, a flow meter and a gas sampling bag are provided on the produced gas inlet pipe of the produced gas processing device, and a fourth valve is provided at the gas inlet of the gas sampling bag. Before the produced gas is processed, the first valve is closed, the fourth valve is turned on, and the produced gas enters the gas sampling bag. After a set time period, the fourth valve is closed and the first valve is turned on. The analysis device determines the total volume of the produced gas in the gas sampling bag within the set time period based on the flow rate detected by the flow meter within the set time period, and then detects the concentration of methane in the gas sampling bag to determine the output volume of methane within the set time period.

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

[0053] The core used in the experiment has a specification of 10×30×30cm; the volume of the second absorption bottle is 2.0L, and the carbon dioxide absorbent in the second absorption bottle is a 10.0wt% sodium hydroxide solution; the volume of the first absorption bottle is 1.0L, and the carbon dioxide absorbent in the first absorption bottle is a 5.0%wt% diethanolamine solution; the carbon dioxide indicator in the first indicator bottle and the second indicator bottle is a 0.3wt% calcium hydroxide solution; the pore size of the porous sheet is 45.5μm; the volume of the collection bottle is 5.0L. In the actual indoor simulation experiment, after the carbon dioxide in the produced gas is absorbed by the two-stage absorption bottle, there is no precipitation or turbidity in the solution in the indicator bottle, indicating that the carbon dioxide is completely absorbed.

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

[0055] The core used in the experiment has a size of φ2.5×100cm; the volume of the second absorption bottle is 1.0L, and the carbon dioxide absorbent in the second absorption bottle is 8.5wt% sodium hydroxide solution; the volume of the first absorption bottle is 1L, and the carbon dioxide absorbent in the first absorption bottle is 4.5%wt% diethanolamine solution; the carbon dioxide indicator in the first indicator bottle and the second indicator bottle is 0.4wt% calcium hydroxide solution; the pore size of the porous sheet is 35.5μm; the volume of the collection bottle is 2.5L. In the actual indoor simulation experiment, after the carbon dioxide in the produced gas is absorbed by the two-stage absorption bottle, there is no precipitation or turbidity in the solution in the indicator bottle, indicating that the carbon dioxide is completely absorbed.

[0056] Example 3: Treatment of produced gas from heterogeneous plate-shaped core flooding experiment

[0057] The core used in the experiment has a specification of 2.5×2.5×30cm; the volume of the second absorption bottle is 0.5L, and the carbon dioxide absorbent in the second absorption bottle is a 6.0wt% sodium hydroxide solution; the volume of the first absorption bottle is 0.5L, and the carbon dioxide absorbent in the first absorption bottle is a 3.5%wt% diethanolamine solution; the carbon dioxide indicator in the first indicator bottle and the second indicator bottle is a 0.5wt% calcium hydroxide solution; the pore size of the porous sheet is 25.0μm; the volume of the collection bottle is 1.0L. In the actual indoor simulation experiment, after the carbon dioxide in the produced gas is absorbed by the two-stage absorption bottle, there is no precipitation or turbidity in the solution in the indicator bottle, indicating that the carbon dioxide is completely absorbed.

[0058] Example 4: Separation and measurement of produced gas from columnar short core displacement experiment

[0059] The core used in the experiment has a specification of φ2.5×7.5cm; the volume of the second absorption bottle is 0.5L, and the carbon dioxide absorbent in the second absorption bottle is a 5.0wt% sodium hydroxide solution; the volume of the first absorption bottle is 0.5L, and the carbon dioxide absorbent in the first absorption bottle is a 3.0%wt% diethanolamine solution; the carbon dioxide indicator in the first indicator bottle and the second indicator bottle is a 0.5wt% calcium hydroxide solution; the pore size of the porous sheet is 15μm; the volume of the collection bottle is 0.5L. In the actual indoor simulation experiment, the carbon dioxide in the produced gas has been completely absorbed in the first absorption bottle, and there is no precipitation or turbidity in the solution in the indicator bottle, indicating that the carbon dioxide has been completely absorbed.

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

[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, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope 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 suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0063] In addition, 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 collecting 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, arranged between the first absorption bottle and the first indicator bottle, wherein the air inlet of the circulation absorption tube is arranged 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, arranged on the circulating absorption pipe, for opening 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 arranged on the gas outlet pipe of the first indicator bottle, and is used to shut off when the produced gas outputted from the first absorption bottle contains carbon dioxide, and to open when the produced gas outputted 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 displacement experiment also includes: an image acquisition device, used for acquiring a first indicator image of the first indicator bottle and sending the first indicator image to a control device; A control device is communicatively connected with 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 displacement experiment according to claim 2, characterized in that: The produced gas processing device in the core displacement experiment also includes: A second indicator bottle is arranged between the first indicator bottle and the methane collecting device, wherein the second indicator bottle contains 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 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.

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 displacement 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 a 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 displacement experiment according to claim 4, characterized in that: The produced gas processing device in the core displacement 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 displacement 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 displacement 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, and 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 displacement 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 displacement 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 in a core displacement experiment comprising any one of claims 1 to 9.

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