Carbon dioxide huff and puff experimental device for tight oil reservoir

Abstract

The embodiment of the present application provides a kind of carbon dioxide huff and puff experimental device under compact oil reservoir, it is related to oil and gas development technical field.The experimental device includes: sample chamber, sample chamber has accommodating cavity;Injection structure is used to inject water and oil to accommodating cavity, to make rock core sample be filled with water and oil, and injection structure is used to inject carbon dioxide into accommodating cavity, to make carbon dioxide enter rock core sample and produce part water oil;Pressure control system is used to apply pressure to rock core sample;Heating device is used to heat rock core sample;Pore detection device is used to detect the pressure in sample chamber;Resistance meter is used to detect the resistance parameter of water and oil in rock core sample.Compared with prior art, the amount of water and oil contained in rock core sample can be detected and calculated using pore detection device and resistance meter, with high precision and small error, which can adjust the injection parameters of carbon dioxide according to the water and oil content in rock core sample, and improve the experimental efficiency.

Description

Technical Field

[0001] This application relates to the field of oil and gas development technology, and in particular to a carbon dioxide huff and puff experimental apparatus in tight oil reservoirs. Background Technology

[0002] Tight oil reservoirs are characterized by low porosity and low permeability. These reservoirs are typically found in sandstone or limestone, where the tightness of the rock results in high viscosity and poor flowability of the crude oil. To further improve oil recovery, carbon dioxide (CO2) gas is often injected into tight oil reservoirs. CO2's viscosity-reducing and high-emission properties allow it to mix with the crude oil, enhancing its flowability and displacing residual oil from the reservoir's pores. The appropriateness of parameters such as the CO2 injection pressure and rate directly affects the extraction of residual oil from the reservoir's pores. Therefore, CO2 huff and puff testing is typically conducted using multiple experiments to determine the optimal injection parameters.

[0003] In related technologies, the carbon dioxide huff and puff experimental device includes an injection structure, a pressure control structure, a heating device, and a recovery and metering system. Water and oil are injected into the core sample through the injection structure, resulting in water and oil content within the core pores. The pressure control structure and heating device apply pressure and heat to the core sample, simulating a primitive underground tight oil reservoir. Carbon dioxide is then injected into the core sample through the injection structure, and the well is left to stand for a period of time to extract some of the water and oil. The recovery and metering system measures the amount of water and oil extracted. The carbon dioxide injection parameters are adjusted multiple times to increase the amount of water and oil extracted.

[0004] However, the adjustment of carbon dioxide injection parameters is related to the water and oil content in the core pores. Since the water and oil content in the core pores cannot be accurately obtained, the direction of carbon dioxide injection parameter adjustment is deviated, which in turn increases the number of experiments and makes the experiments more complicated. Utility Model Content

[0005] This application provides a carbon dioxide injection and release experimental device for tight oil reservoirs to overcome the limitations of existing technologies where the water and oil content in the core pores cannot be accurately obtained. However, the adjustment of carbon dioxide injection parameters is related to the water and oil content in the core pores, which leads to deviations in the direction of carbon dioxide injection parameter adjustment, resulting in an increase in the number of experiments and making the experiments cumbersome.

[0006] This application provides a carbon dioxide huff and puff experimental apparatus for tight oil reservoirs, comprising: a sample chamber having a receiving cavity, the sample chamber being used to contain core samples.

[0007] An injection structure is provided, which is connected to the sample chamber. The injection structure is used to inject water and oil into the receiving cavity respectively, so that the pores of the core sample are filled with water and oil. The injection structure is also used to inject carbon dioxide into the receiving cavity, so that the carbon dioxide enters the core sample and extracts part of the injected water and oil from the core sample.

[0008] A pressure control system is used to apply pressure to the core sample.

[0009] A heating device for heating the core sample.

[0010] A pore detection device is connected to the sample chamber and is used to detect the pressure inside the sample chamber.

[0011] A resistance meter is connected to the core sample and is used to detect the resistance parameters of water and oil within the core sample.

[0012] In one possible implementation, the porosity detection device includes a gas measurement standard chamber, a pressure gauge, and a shut-off valve. The gas measurement standard chamber is connected to the sample chamber via a pipeline. The pressure gauge and the shut-off valve are installed on the pipeline. The pressure gauge is used to detect the initial pressure of a fixed amount of gas sealed in the gas measurement standard chamber and the stable pressure of the gas after it expands into the sample chamber.

[0013] In one possible implementation, the injection structure includes a water tank, an oil tank, and a carbon dioxide collecting cylinder.

[0014] The water storage tank is connected to the sample chamber via a water injection pipe, which is used to inject water into the sample chamber so that the water is injected into the pores of the rock core sample.

[0015] The oil storage tank is connected to the sample chamber via an oil injection pipe, which is used to inject oil into the sample chamber so that the oil is injected into the pores of the core sample.

[0016] The carbon dioxide collecting bottle is connected to the sample chamber via a gas delivery pipe. The gas delivery pipe is used to inject carbon dioxide into the sample chamber so that the carbon dioxide enters the pores of the core sample to extract some of the water and oil injected into the core sample.

[0017] In one possible implementation, the injection structure further includes a cooling assembly and a carbon dioxide collection bottle, the carbon dioxide collection bottle being connected to the carbon dioxide gas collection bottle via the cooling assembly, and the outlet end of the carbon dioxide collection bottle being connected to the sample chamber.

[0018] The carbon dioxide collecting bottle is used to store gaseous carbon dioxide, the carbon dioxide liquid collecting bottle is used to store liquid carbon dioxide, and the cooling assembly is used to condense the gaseous carbon dioxide into liquid carbon dioxide.

[0019] In one possible implementation, the cooling assembly includes a condenser tube and a cooling fan, the carbon dioxide gas collecting bottle and the carbon dioxide liquid collecting bottle are connected through the condenser tube, and the cooling fan is used to blow cooling air toward the condenser tube.

[0020] In one possible implementation, a data acquisition and monitoring system is also included, which comprises a first pressure regulating pump, a second pressure regulating pump, a temperature controller, and a carbon dioxide electromagnetic flow meter.

[0021] Both the water storage tank and the oil storage tank are connected to the first pressure regulating pump, which is used to detect and regulate the pressure of the water and the oil being transported.

[0022] The second pressure regulating pump is connected to the carbon dioxide collection bottle, and the second pressure regulating pump is used to detect and regulate the pressure of delivering the carbon dioxide.

[0023] The temperature controller is located downstream of the carbon dioxide collecting bottle and is used to monitor the temperature of the carbon dioxide.

[0024] The carbon dioxide electromagnetic flow meter is located downstream of the temperature controller and is used to detect the amount of carbon dioxide injected.

[0025] In one possible implementation, the data acquisition and monitoring system further includes a monitoring display, wherein the first pressure regulating pump, the second pressure regulating pump, the temperature controller, and the carbon dioxide electromagnetic flow meter are all electrically connected to the monitoring display.

[0026] In one possible implementation, the pressure control system includes a confining pressure pump and an axial pressure pump. The confining pressure pump is connected to the side of the sample chamber and is used to apply lateral confining pressure to the core sample. The axial pressure pump is connected to both ends of the sample chamber and is used to apply axial pressure to the core sample.

[0027] In one possible implementation, a recovery metering system is also included, which is connected to the outlet of the sample chamber and is used to measure the amount of water and oil extracted from the core sample by the carbon dioxide.

[0028] In one possible implementation, the recovery metering system includes an oil-water-gas three-phase separator, a flow meter, and a carbon dioxide monitor. The oil-water-gas three-phase separator is connected to the sample chamber via the carbon dioxide monitor, which is used to detect whether carbon dioxide is discharged from the core sample. The flow meter is connected to the outlet of the oil-water-gas three-phase separator and is used to measure the amount of water and oil extracted from the core sample by the carbon dioxide.

[0029] The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs provided in this application includes a porosity detection device to monitor the pressure within the sample chamber containing the core sample. The core sample is pressurized and heated using a pressure control system and a heating device. Water and oil are injected into the containment cavity of the sample chamber using an injection structure, ensuring that the pores of the core sample are filled with water and oil, simulating a formation environment. The resistance parameters of the water and oil within the pores of the core sample are detected and obtained using a resistance meter. By combining these resistance parameters with the pressure data obtained from the porosity detection device, the amount of water and oil contained in the core sample can be calculated.

[0030] Therefore, the carbon dioxide injection and release experimental device for tight oil reservoirs provided in this application embodiment, compared with the prior art, allows the amount of water and oil contained in the core sample to be detected and calculated using a porosity detection device and a resistance meter. This method is highly accurate and has a small error, making it convenient to adjust the carbon dioxide injection parameters according to the water-oil content ratio in the core sample during subsequent experiments. For example, when the oil content is high, the carbon dioxide injection pressure and injection volume can be appropriately increased and the well simmering time can be extended during subsequent experiments so that the carbon dioxide can be fully mixed with the oil in the core sample. This ensures that the direction of adjusting the carbon dioxide injection parameters during subsequent experiments is correct and improves experimental efficiency. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] Figure 1 This is a schematic diagram of the carbon dioxide huff and puff experimental apparatus in tight oil reservoirs provided in this application.

[0033] Explanation of reference numerals in the attached figures:

[0034] 100 - Sample chamber; 110 - Reception cavity;

[0035] 200 - Injection structure; 210 - Water storage tank; 211 - Water injection pipe; 220 - Oil storage tank; 221 - Oil injection pipe; 230 - Carbon dioxide gas collecting bottle; 231 - Gas delivery pipe; 240 - Carbon dioxide liquid collecting bottle; 250 - Cooling assembly; 251 - Condenser pipe; 252 - Cooling fan; 260 - Input pipe;

[0036] 300 - Pressure control system; 310 - Confining pressure pump; 320 - Axial pressure pump;

[0037] 400 - Heating device;

[0038] 500 - Porosity detection device; 510 - Gas testing standard chamber; 520 - Pressure gauge; 530 - Shut-off valve; 540 - Pipeline;

[0039] 600-ohmmeter;

[0040] 700 - Data acquisition and monitoring system; 710 - First pressure regulating pump; 711 - Multi-way valve; 720 - Second pressure regulating pump; 730 - Temperature controller; 740 - Carbon dioxide electromagnetic flow meter; 750 - Monitoring display;

[0041] 800 - Recovery metering system; 810 - Oil-water-gas three-phase separator; 820 - Flow meter; 830 - Carbon dioxide monitor;

[0042] 900-core sample.

[0043] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0044] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0045] The terms "first," "second," "third," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0046] Secondly, it should be noted that in the description of this application, the terms "inner", "outer", "first direction", "second direction", etc., which indicate the direction or positional relationship, are based on the direction or positional relationship shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or component must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this application.

[0047] Furthermore, it should be noted that, in the description of this application, unless otherwise expressly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0048] As described in the background section, the related technology includes a carbon dioxide injection experimental device comprising an injection structure, a pressure control structure, a heating device, and a recovery metering system. Water and oil are injected into the core sample through the injection structure, resulting in water and oil content within the core pores. The pressure control structure and heating device apply pressure and heat to the core sample, simulating a primitive underground tight oil reservoir. Carbon dioxide is then injected into the core sample through the injection structure, and the well is left to stand for a period of time to extract some of the water and oil. The recovery metering system measures the amount of water and oil extracted. The carbon dioxide injection parameters are adjusted multiple times to increase the amount of water and oil extracted.

[0049] However, the adjustment of carbon dioxide injection parameters is related to the water and oil content in the core pores. Since the water and oil content in the core pores cannot be accurately obtained, the direction of carbon dioxide injection parameter adjustment is deviated, which in turn increases the number of experiments and makes the experiments more complicated.

[0050] To address the aforementioned technical problems, this application provides a carbon dioxide huff and puff experimental apparatus for tight oil reservoirs. The apparatus includes: a sample chamber having a receiving cavity for containing a core sample; an injection structure connected to the sample chamber for injecting water and oil into the receiving cavity to fill the pores of the core sample with water and oil, and for injecting carbon dioxide into the receiving cavity to allow carbon dioxide to enter the core sample and extract a portion of the injected water and oil from the core sample; a pressure control system for applying pressure to the core sample; a heating device for heating the core sample; a porosity detection device connected to the sample chamber for detecting the pressure within the sample chamber; and a resistance meter connected to the core sample for detecting the resistance parameters of water and oil within the core sample.

[0051] Compared to existing technologies, the amount of water and oil contained in core samples can be detected and calculated using a porosity detection device and a resistance meter. This method offers high accuracy and low error, allowing experimenters to adjust carbon dioxide injection parameters based on the water and oil content in the core sample, thereby improving experimental efficiency.

[0052] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0053] This application provides a carbon dioxide huff and puff experimental apparatus for tight oil reservoirs, combined with Figure 1 As shown, it includes: a sample chamber 100, the sample chamber 100 having a receiving cavity 110, the sample chamber 100 being used to receive a core sample 900.

[0054] The injection structure 200 is connected to the sample chamber 100. The injection structure 200 is used to inject water and oil into the receiving cavity 110 respectively, so that the pores of the core sample 900 are filled with water and oil. The injection structure 200 is also used to inject carbon dioxide into the receiving cavity 110, so that carbon dioxide enters the core sample 900 and extracts part of the water and oil injected into the core sample 900.

[0055] Pressure control system 300 is used to apply pressure to core sample 900.

[0056] Heating device 400 is used to heat core sample 900.

[0057] A pore detection device 500 is connected to the sample chamber 100 and is used to detect the pressure inside the sample chamber 100.

[0058] Rheometer 600 is connected to core sample 900 and is used to detect the resistance parameters of water and oil in core sample 900.

[0059] It is understandable that introducing carbon dioxide into an underground oil reservoir and allowing the well to remain saturated for a period of time allows the carbon dioxide to mix with the crude oil, enhancing its fluidity and enabling the extraction of residual oil from the reservoir pores. However, in actual operation, it is difficult to accurately control parameters such as the injection volume, pressure, and rate of carbon dioxide. Therefore, the injection parameters need to be repeatedly adjusted using an experimental setup to obtain oil recovery rates under different conditions, thus determining the appropriate carbon dioxide injection parameters. The direction of these parameter adjustments is related to the water and oil content within the core pores. For example, when the oil content in the core pores is high, the carbon dioxide injection pressure and volume can be appropriately increased, and the saturation time extended, to ensure sufficient miscibility between the carbon dioxide and the oil in the core. Therefore, the experimental setup needs to accurately obtain the water and oil content within the core to ensure the correct direction of carbon dioxide injection parameter adjustments during subsequent experiments and improve experimental efficiency.

[0060] Specifically, a porosity detection device 500 is used to detect the pressure inside the sample chamber 100 containing the core sample 900. The core sample 900 is pressurized and heated via a pressure control system 300 and a heating device 400. Water and oil are injected into the receiving cavity 110 within the sample chamber 100 using an injection structure 200, ensuring the pores of the core sample 900 are filled with water and oil, simulating a formation environment. A resistance meter 600 detects and obtains the resistance parameters of the water and oil within the pores of the core sample 900. Combining these resistance parameters with the pressure data obtained from the porosity detection device 500 allows for the calculation of the amount of water and oil contained in the core sample 900. This method is highly accurate with minimal error, enabling experimenters to adjust the carbon dioxide injection parameters based on the water and oil content within the core sample 900, thus improving experimental efficiency.

[0061] It should be noted that blindly increasing or decreasing the amount and pressure of carbon dioxide injection may not only lead to energy waste, but may also cause a decrease in oil recovery rate and irreversible damage to underground rock reservoirs.

[0062] In one possible implementation, reference is made to Figure 1 As shown, the porosity detection device 500 includes a gas measurement standard chamber 510, a pressure gauge 520, and a shut-off valve 530. The gas measurement standard chamber 510 is connected to the sample chamber 100 through a pipe 540. The pressure gauge 520 and the shut-off valve 530 are installed on the pipe 540. The pressure gauge 520 is used to detect the initial pressure of a quantitative gas sealed in the gas measurement standard chamber 510 and the stable pressure after the gas expands into the sample chamber 100.

[0063] Specifically, the porosity detection device 500 also includes a vacuum pump (not shown in the figure). When using the porosity detection device 500, the core sample 900 is first placed in the sample chamber 100, the sample chamber 100 is sealed, and the shut-off valve 530 is closed to prevent gas flow. Then, the vacuum pump is turned on to evacuate the sample chamber 100 until a vacuum level is reached. A quantitative amount of inert gas is then injected into the gas standard chamber 510, and the pressure of the sealed quantitative gas in the gas standard chamber 510 is detected using a pressure gauge 520.

[0064] Finally, the shut-off valve 530 is opened, allowing the gas in the gas measurement standard chamber 510 to expand and flow into the sample chamber 100. After the pressure stabilizes, the pressure gauge 520 can be used to detect the stable pressure after the gas expands into the sample chamber 100. Thus, the pore volume and porosity of the rock core sample 900 in the sample chamber 100 can be calculated. This allows for the calculation of the amount of water and oil contained in the rock core sample 900 by combining the resistivity parameters of the water and oil contained in the rock core sample 900. The calculation is accurate with small error.

[0065] Furthermore, during the operation, a vacuum operation is first performed to ensure that there are no other types of gases in the sample chamber except for the inert gas that is circulating within it. This avoids competitive adsorption of multiple gases, which could cause errors in the experiment. As a result, the equilibrium pressure detected is more accurate, and the experimental precision is improved.

[0066] In one possible implementation, reference is made to Figure 1 As shown, the injection structure 200 includes a water storage tank 210, an oil storage tank 220, and a carbon dioxide collection cylinder 230.

[0067] The water storage tank 210 is connected to the sample chamber 100 through the water injection pipe 211, which is used to inject water into the sample chamber 100 so that the water is injected into the pores of the core sample 900.

[0068] The oil storage tank 220 is connected to the sample chamber 100 through the oil injection pipe 221. The oil injection pipe 221 is used to inject oil into the sample chamber 100 so that the oil is injected into the pores of the core sample 900.

[0069] The carbon dioxide collecting bottle 230 is connected to the sample chamber 100 through the gas supply pipe 231. The gas supply pipe 231 is used to inject carbon dioxide into the sample chamber 100 so that the carbon dioxide enters the pores of the core sample 900 to extract part of the water and oil injected into the core sample 900.

[0070] Specifically, in combination Figure 1As shown, the water storage tank 210, the oil storage tank 220, and the carbon dioxide gas collecting cylinder 230 are independent of each other. Control valves are installed on the water injection pipe 211 connected to the water storage tank 210, the oil injection pipe 221 connected to the oil storage tank 220, and the gas transmission pipe 231 connected to the carbon dioxide gas collecting cylinder 230.

[0071] The outlet ends of the water injection pipe 211, oil injection pipe 221 and gas transmission pipe 231 can converge to the input pipe 260. The input pipe 260 is connected to the sample chamber 100 to deliver water, oil and carbon dioxide into the sample chamber 100 to simulate carbon dioxide huff and puff oil production under the formation environment.

[0072] Furthermore, such as Figure 1 As shown, the injection structure 200 also includes a cooling assembly 250 and a carbon dioxide collection bottle 240. The carbon dioxide collection bottle 240 is connected to the carbon dioxide collection bottle 230 through the cooling assembly 250, and the outlet end of the carbon dioxide collection bottle 240 is connected to the sample chamber 100.

[0073] The carbon dioxide collecting bottle 230 is used to store gaseous carbon dioxide, the carbon dioxide liquid collecting bottle 240 is used to store liquid carbon dioxide, and the cooling component 250 is used to condense gaseous carbon dioxide into liquid carbon dioxide.

[0074] It's understandable that carbon dioxide is a gas at room temperature, while the underground environment is characterized by high temperature and pressure. When carbon dioxide is injected into the rock beneath the surface, it will become liquid or supercritical. When gaseous carbon dioxide suddenly enters this high-temperature, high-pressure environment, it will expand, potentially damaging pipelines. Therefore, before being transported into the underground rock, gaseous carbon dioxide can be condensed into liquid carbon dioxide and transported in liquid form to improve safety.

[0075] Furthermore, such as Figure 1 As shown, the cooling assembly 250 includes a condenser pipe 251 and a cooling fan 252. The carbon dioxide gas collecting bottle 230 and the carbon dioxide liquid collecting bottle 240 are connected through the condenser pipe 251, and the cooling fan 252 is used to blow cooling air toward the condenser pipe 251.

[0076] Specifically, such as Figure 1 As shown, the cooling fan 252 can blow cooling air toward the condenser tube 251 to condense gaseous carbon dioxide into liquid carbon dioxide.

[0077] The condenser tube 251 can be arranged in a serpentine bend to increase the cooling area.

[0078] Of course, in other embodiments, the cooling component 250 may also be a heat exchanger, without specific limitations.

[0079] In one possible implementation, reference is made to Figure 1 As shown, it also includes a data acquisition and monitoring system 700, which includes a first pressure regulating pump 710, a second pressure regulating pump 720, a temperature controller 730, and a carbon dioxide electromagnetic flow meter 740.

[0080] Both the water storage tank 210 and the oil storage tank 220 are connected to the first pressure regulating pump 710, which is used to detect and regulate the pressure of the water and oil being transported.

[0081] The second pressure regulating pump 720 is connected to the carbon dioxide collecting bottle 240 and is used to detect and regulate the pressure of the delivered carbon dioxide.

[0082] The temperature controller 730 is located downstream of the carbon dioxide collecting bottle 240 and is used to monitor the temperature of the carbon dioxide.

[0083] The carbon dioxide electromagnetic flow meter 740 is located downstream of the temperature controller 730 and is used to detect the amount of carbon dioxide injected.

[0084] Specifically, both the first pressure regulating pump 710 and the second pressure regulating pump 720 can display the pressure application time and the flow rate, so as to accurately adjust the pressure and flow rate delivered to the sample chamber 100.

[0085] Furthermore, all pipes in the experimental setup are opaque to simulate the process of using carbon dioxide for oil recovery in a formation environment. Therefore, a temperature controller 730 can be installed on the input pipe 260, located downstream of the carbon dioxide collection bottle 240, to detect whether the liquid carbon dioxide output from the collection bottle 240 meets the standards, ensuring that the carbon dioxide delivered to the core sample 900 is liquid carbon dioxide, thus further improving the safety factor.

[0086] And, as Figure 1 As shown, the first pressure regulating pump 710 is connected to the water storage tank 210 and the oil storage tank 220 through the multi-way valve 711. Before the experiment begins, the first pressure regulating pump 710 can be used to pressurize the multi-way valve 711 and observe whether water is flowing out of the multi-way valve 711 to determine whether the airtightness of the experimental device is good, so as to avoid the entry of impurities and gases that may affect the experimental results.

[0087] Of course, pressure gauges can be installed on the water injection pipe 211, oil injection pipe 221 and gas transmission pipe 231 to further ensure the airtightness of each pipeline.

[0088] The carbon dioxide electromagnetic flow meter 740 is located downstream of the temperature controller 730. After the temperature controller 730 confirms that the carbon dioxide can be delivered to the core sample 900, the carbon dioxide electromagnetic flow meter 740 can detect the amount of carbon dioxide injected into the core sample 900.

[0089] Furthermore, such as Figure 1 As shown, the data acquisition and monitoring system 700 also includes a monitoring display 750, and the first pressure regulating pump 710, the second pressure regulating pump 720, the temperature controller 730 and the carbon dioxide electromagnetic flow meter 740 are all electrically connected to the monitoring display 750.

[0090] Understandably, the first pressure regulating pump 710, the second pressure regulating pump 720, the temperature controller 730, and the carbon dioxide electromagnetic flow meter 740 are all electrically connected to the monitoring display 750 so that the data on carbon dioxide temperature, injection volume, and injection pressure obtained from monitoring can be transmitted to the monitoring display 750 in real time. The monitoring display 750 can display the current data in real time so that the experimenter can observe and record it.

[0091] In one possible implementation, such as Figure 1 As shown, the pressure control system 300 includes a confining pressure pump 310 and an axial pressure pump 320.

[0092] The confining pressure pump 310 is connected to the side of the sample chamber 100 and is used to apply lateral confining pressure to the core sample 900.

[0093] The axial pressure pump 320 is connected to both ends of the sample chamber 100 and is used to apply axial pressure to the core sample 900.

[0094] It is understandable that rock cores are subjected to all-directional pressures under formation conditions. Therefore, confining pressure pump 310 and axial pressure pump 320 can be set to apply lateral confining pressure and axial pressure to the rock core sample 900 to simulate the formation environment and improve experimental accuracy.

[0095] Furthermore, under the pressure of the confining pressure pump 310 and the axial pressure pump 320, the core sample 900 can be fixed, preventing the core sample 900 from moving and affecting the experimental results.

[0096] In one possible implementation, combined with Figure 1 As shown, it also includes a recovery metering system 800, which is connected to the sample chamber 100. The recovery metering system 800 is used to measure the amount of water and oil extracted by carbon dioxide in the core sample 900.

[0097] Specifically, in combination Figure 1As shown, the inlet of sample chamber 100 is connected to injection structure 200, and the outlet of sample chamber 100 is connected to recovery metering system 800. Carbon dioxide enters core sample 900 through injection structure 200 to extract some of the water and oil contained in core sample 900. The water and oil extracted by carbon dioxide injection can be transported to recovery metering system 800. Recovery metering system 800 can detect the amount of water and oil extracted, and thus the recovery rate can be calculated based on the amount of water and oil extracted and the initial amount of water and oil contained in core sample 900 calculated above. This allows the experimenter to confirm whether the carbon dioxide injection parameters have reached the optimal level based on the obtained recovery rate.

[0098] Furthermore, the recovery metering system 800 includes an oil-water-gas three-phase separator 810, a flow meter 820, and a carbon dioxide monitor 830. The oil-water-gas three-phase separator 810 is connected to the sample chamber 100 through the carbon dioxide monitor 830. The carbon dioxide monitor 830 is used to detect whether carbon dioxide is discharged from the core sample 900. The flow meter 820 is connected to the outlet end of the oil-water-gas three-phase separator 810. The flow meter 820 is used to measure the amount of water and oil extracted from the core sample 900 through carbon dioxide.

[0099] Specifically, such as Figure 1 As shown, the oil-water-gas three-phase separator 810 is connected to the sample chamber 100 via an output pipe, and a carbon dioxide monitor 830 is installed on the output pipe. The carbon dioxide monitor 830 is used to detect whether carbon dioxide is emitted from the core sample 900 to determine whether the experiment has been completed. The oil-water-gas three-phase separator 810 can receive the water and oil extracted from the core sample 900 by carbon dioxide. After the experiment is completed, the water and oil received by the oil-water-gas three-phase separator 810 can be separated. A flow meter 820 is connected to the oil-water-gas three-phase separator 810, and the flow meter 820 can be used to detect the amount of extracted water and oil.

[0100] It should be noted that when conducting carbon dioxide swallowing and releasing experiments, the following steps can be followed: First, select the rock core sample 900 required for the experiment, place the rock core sample 900 in the sample chamber 100, and seal the sample chamber 100.

[0101] Then, the pressure data inside the sample chamber 100 was measured using the pore detection device 500, and the pore volume of the core sample 900 was calculated. and core porosity .

[0102] Then, the pore detection device 500 is turned off, the pressure control system 300 is turned on, and pressure is applied to the core sample 900 until the preset pressure value under the simulated strata is reached.

[0103] Then, the airtightness of each pipeline in the experimental setup was tested using a pressure gauge and a multi-way valve 711.

[0104] After confirming good airtightness, prepare water with the same salinity as the simulated formation, open the water storage tank 210 of the injection structure 200, and inject the water into the sample chamber 100 so that the water enters the core sample 900; when the flow rate entering the sample chamber 100 is the same as the flow rate exiting the sample chamber 100, close the water storage tank 210 to ensure that the pores of the core sample 900 are filled with water.

[0105] Turn on the heating device 400 to heat the core sample 900 to the preset temperature simulating the strata below.

[0106] The oil storage tank 220 of the injection structure 200 is opened, and oil is injected into the sample chamber 100. This oil displaces most of the water in the core sample 900 and stores it in the pores. When the flow rate entering the sample chamber 100 matches the flow rate exiting the sample chamber 100, and when water can no longer be displaced, the oil storage tank 220 is closed, ensuring that the pores of the core sample 900 are filled with oil, simulating an underground oil reservoir. At this time, the pores of the core sample 900 are enriched with undisplaced water (bound water) and oil. It should be noted that the oil injection pressure can be less than the confining pressure applied in the pressure control system 300 to avoid crossflow within the core sample 900 during the oil injection process.

[0107] Then, turn on the resistance meter 600 and use the resistance meter 600 to detect the resistivity of water and oil in the core sample 900 at this time. Combined with the porosity and pore volume of the core sample 900, the content of water and oil in the core sample 900 is calculated.

[0108] Subsequently, the carbon dioxide collecting bottle 230 of the injection structure 200 can be opened to introduce carbon dioxide into the pores of the core sample 900 within the sample chamber 100, thereby displacing water and oil from the core sample 900. When the flow rate of carbon dioxide injected into the sample chamber 100 matches the flow rate exiting the sample chamber 100, the carbon dioxide collecting bottle 230 is closed. At this point, the more fluid water and oil within the core sample 900 have been displaced. The sample chamber 100 is then sealed to perform a well-clogging operation, allowing the carbon dioxide to fully mix with the remaining oil, increasing oil fluidity and improving oil recovery.

[0109] It should be noted that after the carbon dioxide in the core sample 900 has fully dissipated, the sample chamber 100 and the recovery metering system 800 can be opened. Some of the water and oil in the core sample 900 will flow through the sample chamber 100 to the oil-water-gas three-phase separator 810 in the recovery metering system 800. The oil-water-gas three-phase separator 810 will be used to separate the discharged water, oil and carbon dioxide and obtain the extracted volume of the three, thereby obtaining the carbon dioxide sequestration amount.

[0110] In addition, the amount of water and oil contained in the core sample 900 can be determined based on the resistance parameters of the water and oil contained in the core sample 900 and the pressure data detected by the pore detection device 500. The calculation of the amount of water and oil contained in the core sample 900 includes the following steps.

[0111] The pressure in the sample chamber 100 is detected by the porosity detection device 500, and the volume inside the sample chamber 100 containing the core sample 900 is calculated using Formula 1. .

[0112]

[0113] In the formula: The volume of the gas measurement standard chamber 510 in the porosity detection device 500 is given. This refers to the volume within sample chamber 100, which contains 900 core samples. The volume of pipe 540 between gas measurement standard chamber 510 and sample chamber 100. The initial pressure inside the gas measurement standard chamber 510, The equilibrium pressure after the gas measurement standard chamber 510 and the sample chamber 100 are balanced.

[0114] Based on the volume of sample chamber 100 containing core sample 900 The pore volume within 900 mm of the core sample was calculated using Formula 2. .

[0115]

[0116] In the formula: This refers to the volume within sample chamber 100, which contains 900 core samples. This represents the apparent volume of core sample 900. The volume of sample chamber 100 is for a sample chamber without a core sample of 900. This represents the pore volume within 900 mm of the core sample.

[0117] Based on the internal pore volume of the core sample (900 mm) The porosity of core sample 900 was calculated using Formula 3. .

[0118]

[0119] In the formula: This represents the apparent volume of core sample 900. This represents the pore volume within 900 mm of the core sample. The porosity is 900 for the core sample.

[0120] The resistivity of the oil-bearing rock core sample 90 mm was measured using a 600Ω resistance meter. and water resistivity And combined with the porosity of core sample 900 The water saturation of the core sample at 900°C was calculated using Formula 4. .

[0121]

[0122] In the formula: , Lithology coefficient ( , Use 0.5~1.5, generally 1) under normal laboratory conditions. The resistivity of the water injected into core sample 900. The resistivity of the oil in core sample 900 is given. The porosity of the core sample is 900. The bonding coefficient is denoted as . This is the saturation index.

[0123] According to water saturation The water volume in core sample 900 was calculated using formulas 5 and 6 respectively. and oil saturation .

[0124]

[0125] In the formula: This represents the pore volume within 900 mm of the core sample. The water saturation level in the core sample is 900.

[0126] Based on oil saturation The oil-bearing volume in core sample 900 was calculated using Formula 7. .

[0127]

[0128] In the formula, This represents the pore volume within 900 mm of the core sample. The water saturation level in the core sample is 900.

[0129] Understandably, the porosity detection device 500 can detect the pressure data inside the sample chamber 100, and combined with Formula 1, can calculate the volume inside the sample chamber 100 containing the core sample 900. The volume refers to the remaining volume in the sample chamber 100 after removing the volume occupied by the outer surface of the core sample 900, as well as the volume of the pores on the back of the core sample 900.

[0130] Since core sample 900 and sample chamber 100 were selected by the user, the apparent volume of the outer surface of core sample 900 is... And the volume of sample chamber 100 without core sample 900. To ensure consistent data, the pore volume of core sample 900 can be obtained by combining Formula 2. Therefore, the porosity of the core sample 900 can be obtained using Formula 3. .

[0131] Among them, the resistivity of water and oil contained in core sample 900 can be directly measured by the resistance meter, and the lithology of core sample 900 is known data. Therefore, the water saturation in core sample 900 can be obtained by combining formula five. This allows for accurate determination of the water and oil content within 900 mm of the core sample, with high calculation precision. Furthermore, it facilitates the adjustment of the direction of carbon dioxide injection parameters by the experimenter based on the ratio of water to oil content, enabling the rapid acquisition of optimal injection parameters and improving experimental efficiency.

[0132] It should be noted that the amount of carbon dioxide injected into the core sample 900 was detected using a carbon dioxide electromagnetic flowmeter 740. The carbon dioxide emissions from the core sample 900 were obtained by monitoring with a carbon dioxide monitor 830. The amount of carbon dioxide produced by the oil-water-gas three-phase separator 810 is detected. And calculate the carbon dioxide sequestration capacity using Formula 8. .

[0133]

[0134] In the formula, This refers to the amount of carbon dioxide stored. This refers to the amount of carbon dioxide injected. This represents the amount of carbon dioxide extracted. This represents carbon dioxide emissions.

[0135] Among them, the carbon dioxide sequestration capacity is calculated using Formula 8. During the experiment, the carbon dioxide sequestration capacity under different carbon dioxide injection parameters was obtained by adjusting the carbon dioxide injection parameters. This process continues until the maximum amount of carbon dioxide is obtained, thereby determining the carbon dioxide injection parameters and ensuring experimental accuracy.

[0136] Finally, it should be noted that other embodiments of this application will readily conceive of by those skilled in the art upon consideration of the specification and practice of the application disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and alterations may be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A carbon dioxide huff and puff experimental apparatus for tight oil reservoirs, characterized in that, include: The sample chamber (100) has a receiving cavity (110) for receiving a core sample (900). An injection structure (200) is connected to the sample chamber (100). The injection structure (200) is used to inject water and oil into the receiving cavity (110) respectively, so that the pores of the core sample (900) are filled with water and oil. The injection structure (200) is also used to inject carbon dioxide into the receiving cavity (110), so that the carbon dioxide enters the core sample (900) and extracts part of the water and oil injected into the core sample (900). A pressure control system (300) is used to apply pressure to the core sample (900); A heating device (400) is used to heat the core sample (900). A pore detection device (500) is connected to the sample chamber (100) and is used to detect the pressure inside the sample chamber (100). A resistance meter (600) is connected to the core sample (900) and is used to detect the resistance parameters of water and oil in the core sample (900).

2. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 1, characterized in that, The porosity detection device (500) includes a gas measurement standard chamber (510), a pressure gauge (520), and a shut-off valve (530). The gas measurement standard chamber (510) is connected to the sample chamber (100) through a pipe (540). The pressure gauge (520) and the shut-off valve (530) are installed on the pipe (540). The pressure gauge (520) is used to detect the initial pressure of a quantitative gas sealed in the gas measurement standard chamber (510) and the stable pressure of the gas after it expands into the sample chamber (100).

3. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 1, characterized in that, The injection structure (200) includes a water storage tank (210), an oil storage tank (220), and a carbon dioxide collection cylinder (230). The water storage tank (210) is connected to the sample chamber (100) through a water injection pipe (211). The water injection pipe (211) is used to inject water into the sample chamber (100) so that water is injected into the pores of the core sample (900). The oil storage tank (220) is connected to the sample chamber (100) through an oil injection pipe (221). The oil injection pipe (221) is used to inject oil into the sample chamber (100) so that the oil is injected into the pores of the core sample (900). The carbon dioxide collecting bottle (230) is connected to the sample chamber (100) through a gas supply pipe (231). The gas supply pipe (231) is used to inject carbon dioxide into the sample chamber (100) so that the carbon dioxide enters the pores of the core sample (900) to drive out some of the water and oil injected into the core sample (900).

4. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 3, characterized in that, The injection structure (200) further includes a cooling assembly (250) and a carbon dioxide collection bottle (240). The carbon dioxide collection bottle (240) is connected to the carbon dioxide collection bottle (230) through the cooling assembly (250), and the outlet end of the carbon dioxide collection bottle (240) is connected to the sample chamber (100). The carbon dioxide collecting bottle (230) is used to store gaseous carbon dioxide, the carbon dioxide liquid collecting bottle (240) is used to store liquid carbon dioxide, and the cooling assembly (250) is used to condense the gaseous carbon dioxide into liquid carbon dioxide.

5. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 4, characterized in that, The cooling assembly (250) includes a condenser tube (251) and a cooling fan (252). The carbon dioxide gas collecting bottle (230) and the carbon dioxide liquid collecting bottle (240) are connected through the condenser tube (251). The cooling fan (252) is used to blow cooling air toward the condenser tube (251).

6. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 4, characterized in that, It also includes a data acquisition and monitoring system (700), which includes a first pressure regulating pump (710), a second pressure regulating pump (720), a temperature controller (730), and a carbon dioxide electromagnetic flow meter (740). Both the water storage tank (210) and the oil storage tank (220) are connected to the first pressure regulating pump (710), which is used to detect and regulate the pressure of the water and oil being transported. The second pressure regulating pump (720) is connected to the carbon dioxide collecting bottle (240), and the second pressure regulating pump (720) is used to detect and regulate the pressure of delivering the carbon dioxide; The temperature controller (730) is located downstream of the carbon dioxide collecting bottle (240) and is used to monitor the temperature of the carbon dioxide. The carbon dioxide electromagnetic flow meter (740) is located downstream of the temperature controller (730) and is used to detect the amount of carbon dioxide injected.

7. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 6, characterized in that, The data acquisition and monitoring system (700) also includes a monitoring display (750), and the first pressure regulating pump (710), the second pressure regulating pump (720), the temperature controller (730) and the carbon dioxide electromagnetic flow meter (740) are all electrically connected to the monitoring display (750).

8. The experimental apparatus for carbon dioxide huff and puff in tight oil reservoirs according to claim 1, characterized in that, The pressure control system (300) includes a confining pressure pump (310) and an axial pressure pump (320). The confining pressure pump (310) is connected to the side of the sample chamber (100), and the confining pressure pump (310) is used to apply lateral confining pressure to the core sample (900); The axial pressure pump (320) is connected to both ends of the sample chamber (100) and is used to apply axial pressure to the core sample (900).

9. The experimental apparatus for carbon dioxide huff and puff in tight oil reservoirs according to any one of claims 1-8, characterized in that, It also includes a recovery metering system (800), which is connected to the outlet of the sample chamber (100) and is used to measure the amount of water and oil extracted by carbon dioxide in the core sample (900).

10. The carbon dioxide huff and puff experimental apparatus for tight oil reservoirs according to claim 9, characterized in that, The recovery metering system (800) includes an oil-water-gas three-phase separator (810), a flow meter (820), and a carbon dioxide monitor (830). The oil-water-gas three-phase separator (810) is connected to the sample chamber (100) through the carbon dioxide monitor (830). The carbon dioxide monitor (830) is used to detect whether carbon dioxide is discharged from the core sample (900). The flow meter (820) is connected to the outlet end of the oil-water-gas three-phase separator (810). The flow meter (820) is used to measure the amount of water and oil extracted from the core sample (900) through the carbon dioxide.

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