A device and method for studying dynamic dissolution law of acid gas in cracks

Abstract

The application discloses a device and method for researching dynamic dissolution law of acid gas in cracks, belongs to the field of acid gas dissolution experiments in oil and gas field development, and comprises a formation acidification simulation structure which is used for fixing a core slice and simulating a high-temperature and high-pressure environment, a laser image scanning structure which is used for high-DPI color scanning of the core slice, a high-definition microscope structure which is used for providing a high-definition microscopic image of the core slice in multidimensional observation, an acid gas circulation structure which is used for conveying acid gas to the core slice, controlling the flow rate of the acid gas, purifying the acid gas and recovering waste gas, and a computer which is used for receiving and analyzing experimental data. The device simulates a high-temperature and high-pressure formation environment, conveys acid gas to the core slice, and realizes dynamic collection of experimental data of acid gas dissolution through cooperation of the high-definition microscope structure and the laser image scanning structure.

Description

Technical Field

[0001] This invention relates to the field of acid gas dissolution experimental technology in oil and gas field development, and in particular to an apparatus and method for studying the dynamic dissolution law of acid gas in fractures. Background Technology

[0002] In oil and gas field development, geothermal resource utilization, and CO2 geological storage, the interaction mechanism between gas and rock fractures is a core issue affecting engineering efficiency and safety. However, existing technologies for studying the dissolution patterns of acidic gases within fractures still have significant limitations. Traditional experiments are mostly based on homogeneous rock samples or simple porous structures, using methods such as static immersion followed by permeability measurement to characterize the effects, and can only measure macroscopic parameters before and after dissolution.

[0003] Currently, the equipment and methods for measuring surface characteristics are relatively mature, but most are limited to post-experiment measurements and macroscopic parameter characterization, lacking real-time detection of parameters during the experiment. Furthermore, the proposed evaluation methods for the dynamic dissolution characteristics of acidic gases are still lacking. Rock surface dissolution characteristics, surface roughness, and the microscopic flow characteristics of acidic gases can significantly affect the effectiveness of reservoir acidizing, but real-time characterization methods for these parameters are still imperfect and lack rigorous evaluation indicators. Summary of the Invention

[0004] The purpose of this invention is to provide an apparatus and method for studying the dynamic dissolution law of acidic gases in fractures. It simulates a controllable high-temperature and high-pressure formation environment, continuously delivers acidic gases to core slices, and achieves dynamic acquisition of acidic gas dissolution experimental data through high-definition microstructure combined with laser image scanning structure.

[0005] To achieve the above objectives, the present invention provides an apparatus for studying the dynamic dissolution law of acidic gas in fractures, including a formation acidification simulation structure for installing and fixing core slices, and simulating a high-temperature and high-pressure environment to conduct acid gas dissolution core slice observation experiments.

[0006] Laser image scanning structure for high-DPI color scanning of core slices;

[0007] High-resolution microstructure, used to provide high-resolution microscopic images of core slices for multi-dimensional observation;

[0008] The acid gas circulation structure is used to transport acid gas to core slices, control the acid gas flow rate, purify acid gas, and recover waste gas.

[0009] The computer is used to control the various structures, including the layer acidification simulation structure, the laser image scanning structure, the acid gas circulation structure, and the temperature and pressure detection and control structure, and to connect with each structure via circuits, receive and transmit experimental data, and analyze and process the experimental data.

[0010] Preferably, the formation acidification simulation structure includes a high-temperature and high-pressure chamber, which is used to pressurize and heat the formation to simulate the high-temperature and high-pressure environment. An acrylic clamp is provided at the top of the high-temperature and high-pressure chamber, and core slices are fixed in the center of the acrylic clamp. The two sides of the acrylic clamp are connected to the high-temperature and high-pressure chamber through sealing sleeves.

[0011] Preferably, the laser image scanning structure includes a scanner cover for illuminating and scanning the experimental object. The scanner cover is positioned above the acrylic clamping plate, and one side of the scanner cover is hinged to the high-temperature and high-pressure chamber.

[0012] Preferably, the high-definition microstructure includes a high-definition electron microscope for taking high-definition images of core slices in experiments. The high-definition electron microscope is mounted on an adjustment assembly, which is used to adjust the height and horizontal position of the high-definition electron microscope. The high-definition electron microscope is equipped with a level for adjusting it to be horizontal.

[0013] Preferably, the adjustment components include a vertical adjustment frame and a horizontal adjustment frame. The vertical adjustment frame is used to adjust the height and horizontal position of the high-definition electron microscope, and the horizontal adjustment frame is used to adjust the horizontal position of the high-definition electron microscope.

[0014] Preferably, the acid gas circulation structure includes a gas storage tank, which is connected to a high-temperature and high-pressure enclosure via a high-pressure resistant gas pipeline. A gas dryer and a flow controller are installed on the gas pipeline, which are used to dry the gas and control the gas flow rate through the pipeline.

[0015] Preferably, the high-temperature and high-pressure chamber is connected to the waste gas recovery tank through an acid gas purification chamber.

[0016] Preferably, the acrylic clamp is provided with a pipeline interface, and the gas pipeline is connected to the pipeline interface.

[0017] Preferably, it also includes a scanning switch for controlling the scanning cover and a gas delivery switch for controlling the acid gas delivery.

[0018] This invention provides a method for studying the dynamic dissolution behavior of acidic gases within cracks, comprising the following steps:

[0019] Step 1: Take a natural fractured core or a complete core, slice the core to make core slices (for complete cores, the core to be studied needs to be fractured (artificially created fractures) and then assembled), select the feature surface to be observed, and fix the core slices to an acrylic plate.

[0020] Step 2: Install the acrylic clamping plate inside the high-temperature and high-pressure chamber and connect the gas pipeline to the pipeline interface;

[0021] Step 3: Test the sealing performance of the acid gas delivery system;

[0022] Step 4: With the scanner cover open, adjust the position of the high-definition microscope using the longitudinal adjustment bracket, the transverse adjustment bracket, and the level, so that the high-definition microscope can observe and record the characteristic surfaces of the core slice.

[0023] Step 5: Close the scanner cover, adjust the lighting, and perform laser scanning;

[0024] Step 6: Open the gas storage tank, adjust the acid flow rate, and perform a laser scan every 0.1 seconds using computer-designed scanning parameters and record the data. The high-definition sample data acquired by the high-definition microscope and the laser scan image data are transmitted to the computer.

[0025] Step 7: The experimenters use a computer to retrieve the acid flow rate, temperature, and pressure, retrieve images under the corresponding conditions, generate image files, and create analysis reports and logs.

[0026] Therefore, the apparatus and method described above for studying the dynamic dissolution law of acidic gases in cracks have the following beneficial effects:

[0027] 1. This invention solves the problem of observing the static effects of acidification by integrating a laser image scanning structure and a high-definition microstructure. By scanning and transmitting laser images and high-definition images during the experiment in real time, dynamic observation is achieved so as to observe the changing characteristics during the experiment.

[0028] 2. Laser image scanning structure captures the dynamic evolution of the three-dimensional morphology of the rock surface during acidification at high frequency. Combined with high-definition images of high-definition microstructure, it realizes full-scale dynamic monitoring from macro-roughness changes to micro-pore structure evolution, and can accurately capture the transient interface behavior of acid gas diffusion front.

[0029] 3. The acrylic clamp is detachable and adopts a modular design, which can be adapted to core slice samples of different sizes. With the help of computers, high-definition microstructures, and laser image scanning structures, it can generate a comprehensive evaluation report including three-dimensional morphology reconstruction and pore network evolution parameters.

[0030] 4. The device in this invention features a gas storage tank that is easily replaceable via gas pipeline connection, adjustable acid flow rate, adjustable magnification and position of the high-definition electron microscope, and replaceable core slices. The entire experimental condition is easily controlled, enabling observation of various types of experiments.

[0031] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the overall structure of the device used to study the dynamic dissolution law of acidic gas in cracks according to an embodiment of the present invention.

[0033] Figure 2 This is a schematic diagram of the acrylic clamping plate structure according to an embodiment of the present invention;

[0034] Figure 3 This is a schematic diagram of the pipeline interface structure according to an embodiment of the present invention;

[0035] Figure 4 These are high-resolution electron microscope observation sample images from an embodiment of the present invention;

[0036] Figure 5 This is a grayscale image of a high-resolution electron microscope observation sample from an embodiment of the present invention;

[0037] Figure 6 This is a laser scan image from an embodiment of the present invention.

[0038] In the diagram: 1. Gas storage tank; 2. Gas pipeline; 3. Gas dryer and flow controller; 4. Longitudinal adjustment frame; 5. Lateral adjustment frame; 6. High-definition electron microscope; 7. Level; 8. Scanner cover; 9. Computer; 10. Scanning switch; 11. Gas delivery switch; 12. Wiring; 13. High-temperature and high-pressure chamber; 14. Acid gas purification chamber; 15. Waste gas recovery tank; 16. Sealing sleeve; 17. Core slice; 18. Acrylic clamp; 19. Pipeline interface. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0040] It should be noted that the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0041] Similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0042] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0043] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" 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 of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0044] like Figure 1 As shown, the device for studying the dynamic dissolution law of acidic gas in fractures according to the present invention includes a formation acidification simulation structure, a laser image scanning structure, a high-definition microstructure, an acid gas circulation structure, a temperature and pressure detection and control structure, and a computer.

[0045] The formation acidification simulation structure is used to mount and fix core slices 17 and to simulate the high-temperature and high-pressure environment for acid gas dissolution observation experiments on core sections. The formation acidification simulation structure includes a high-temperature and high-pressure chamber 13, which utilizes an existing fully transparent high-temperature and high-pressure reactor to simulate the high-temperature and high-pressure environment of the formation. Figure 2 As shown, an acrylic clamping plate 18 is installed at the top of the high-temperature and high-pressure chamber 13. Core slices 17 are fixed to the center of the acrylic clamping plate 18 (requiring only simple fixing, preventing slippage, eliminating the need for sealing the core slices 17, and minimizing angle changes during the experiment; they also exhibit almost no displacement when placed horizontally). The two sides of the acrylic clamping plate 18 are connected to the high-temperature and high-pressure chamber 13 via sealing sleeves 16. Different core slices 17 can be customized and installed inside the acrylic clamping plate 18. The high-temperature and high-pressure chamber 13 can measure and control temperature and pressure changes during the experiment.

[0046] The laser image scanning structure is used for high-DPI color scanning of core slice 17. The laser image scanning structure includes a scanner cover 8 for illuminating and scanning the experimental object. The scanner cover 8 is positioned above an acrylic clamping plate 18, and one side of the scanner cover 8 is hinged to the high-temperature, high-pressure chamber 13. The scanner cover 8 is a conventional printer scanner cover.

[0047] A high-resolution microstructure is used to provide high-resolution microscopic images of core slice 17 for multi-dimensional observation, allowing for detailed observation of the pore structure of core slice 17. The high-resolution microstructure includes a high-resolution electron microscope 6 for capturing high-resolution images of core slice 17 during experiments. The high-resolution electron microscope 6 is mounted on an adjustment assembly. The adjustment assembly is used to adjust the height and horizontal position of the high-resolution electron microscope 6, and a level 7 is installed on the high-resolution electron microscope 6 to adjust it to a horizontal position. The adjustment assembly includes a longitudinal adjustment frame 4 and a transverse adjustment frame 5. The longitudinal adjustment frame 4 is used to adjust the height and horizontal position of the high-resolution electron microscope 6, and the transverse adjustment frame 5 is used to adjust the horizontal position of the high-resolution electron microscope 6. The longitudinal adjustment frame 4 and the transverse adjustment frame 5 of the adjustment assembly utilize existing XY two-dimensional moving platforms, and the level 7 utilizes existing devices.

[0048] The acid gas circulation structure is used to transport acid gas to the core slice 17, control the acid gas flow rate, purify the acid gas, and recover waste gas. The acid gas circulation structure includes a gas storage tank 1, which is connected to a high-temperature, high-pressure chamber 13 via a high-pressure resistant gas pipeline 2. A gas dryer and a flow controller 3 are installed on the gas pipeline 2. The gas dryer and flow controller 3 are used to dry the gas and control the gas flow rate through the pipeline. The gas dryer and flow controller 3 adopt existing structures. The high-temperature, high-pressure chamber 13 is connected to the waste gas recovery tank 15 via an acid gas purification chamber 14 (the acid gas purification chamber 14 adopts an existing acid gas purification device; in this embodiment, the acid gas purification chamber 14 is a sealed water tank). Figure 3 As shown, the acrylic clamp 18 is provided with a pipeline interface 19, and the gas pipeline 2 is connected to the pipeline interface 19. The gas pipeline 2 needs to be a steel high-pressure displacement pipeline.

[0049] The apparatus for studying the dynamic dissolution behavior of acidic gases within cracks also includes a scanning switch 10 for controlling the scanning cover 8 and a gas delivery switch 11 for controlling the delivery of acidic gases.

[0050] Computer 9 is used to control the various structures, including the acidification simulation structure, the laser image scanning structure, the acid gas circulation structure, and the temperature and pressure detection and control structure, and is electrically connected to each structure (including scanning switch 10, gas delivery switch 11, etc.) via line 12 using existing methods. The computer is also used to receive transmitted experimental data and analyze and process it.

[0051] The method for studying the dynamic dissolution law of acidic gas in cracks according to the present invention includes the following steps:

[0052] Step 1: Take a natural fractured core or a complete core, slice the core to make core slice 17 (for complete cores, the core to be studied needs to be fractured (artificially created fractures) and then assembled), select the feature surface to be observed, and fix core slice 17 to an acrylic plate.

[0053] Step 2: Install the acrylic clamp 18 inside the high temperature and high pressure chamber 13, and connect the gas pipeline 2 to the pipeline interface 19.

[0054] Step 3: Test the airtightness of the acid gas delivery to ensure experimental safety; fix the core slice 17, cover it with the scanner cover 8, prepare for the experiment, only introduce carbon dioxide, and observe the pressure change inside the high temperature and high pressure chamber 13 to test the airtightness.

[0055] Step four: With the scanner cover 8 open, adjust the position of the high-definition microscope using the longitudinal adjustment frame 4 and the transverse adjustment frame 5 in conjunction with the level 7, so that the high-definition microscope can observe and record the characteristic surfaces of the core slice 17.

[0056] Step 5: Close the scanner cover 8, adjust the lighting, and perform laser scanning.

[0057] Step 6: Open gas storage tank 1, adjust acid flow rate, and use computer 9 to design scanning parameters to perform a laser scan every 0.1s and record the data. The high-definition sample acquired by the high-definition microscope and the image data from the laser scan are transmitted to computer 9.

[0058] Step 7: The experimenter uses computer 9 to retrieve the acid flow rate, temperature, and pressure, retrieves images under the corresponding conditions, generates image files, and produces analysis reports and logs.

[0059] The same method is used for cores of different sizes; repeat the steps described above.

[0060] The above experimental methods yielded the following results. Figures 4-6 :

[0061] Figure 4 These are observation samples from a high-resolution electron microscope (HEM) 6. The pore structure of the rock can be clearly observed from the images, which are used to study the changes in rock characteristics before and after acidification. Figure 5 It is based on Figure 4 The generated grayscale images are processed to visually observe the protrusions and depressions of the rocks, thus characterizing the surface features of the rocks.

[0062] Figure 6 These are images processed by laser scanning, scanned at a frequency of 0.1 seconds, to obtain continuous samples of gas flowing through rock pores, used to observe the flow characteristics of fluid in rock fissures and channels and the changing characteristics of rock channels.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A device for studying the dynamic dissolution law of acid gas in a fracture, characterized in that: The acidizing simulation structure is used for fixing the core slice and simulating the high-temperature and high-pressure environment for the acid gas dissolution core slice observation experiment. The laser image scanning structure is used for high-DPI color scanning of the core slice. The high-definition microscope structure is used for providing the high-definition microscopic image of the core slice. The acid gas circulation structure is used for delivering the acid gas to the core slice, controlling the acid gas flow rate, purifying the acid gas and recovering the waste gas. The computer is used for controlling the acidizing simulation structure, the laser image scanning structure, the acid gas circulation structure, the temperature and pressure detection and control structure, receiving the experimental data transmitted by the structures through the lines and analyzing and processing the experimental data. The acidizing simulation structure comprises a high-temperature and high-pressure box body, which is used for pressurizing and heating to simulate the high-temperature and high-pressure environment of the formation. The top end of the high-temperature and high-pressure box body is provided with an acrylic clamp plate. The core slice is fixed at the center of the acrylic clamp plate. The two sides of the acrylic clamp plate are connected with the high-temperature and high-pressure box body through a sealing rubber sleeve. The laser image scanning structure comprises a scanner cover used for illuminating the experimental object and scanning the experimental object. The scanner cover is arranged above the acrylic clamp plate. One side of the scanner cover is hinged to the high-temperature and high-pressure box body. The high-definition microscope structure comprises a high-definition electronic microscope used for shooting the high-definition sample of the core slice in the experiment. The high-definition electronic microscope is arranged on an adjusting assembly. The adjusting assembly is used for adjusting the height and horizontal position of the high-definition electronic microscope. A level is arranged on the high-definition electronic microscope and used for adjusting the high-definition electronic microscope to be horizontal. 2.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 1, characterized in that: The adjusting assembly comprises a longitudinal adjusting frame and a transverse adjusting frame. The longitudinal adjusting frame is used for adjusting the height and horizontal position of the high-definition electronic microscope. The transverse adjusting frame is used for adjusting the horizontal position of the high-definition electronic microscope. 3.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 1, characterized in that: The acid gas circulation structure comprises a gas storage tank. The gas storage tank is connected with the high-temperature and high-pressure box body through a high-pressure-resistant gas pipeline. A gas dryer and a flow controller are arranged on the gas pipeline. The gas dryer and the flow controller are used for drying the gas and controlling the gas flow rate of the pipeline.

4. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 3, characterized in that: The high-temperature and high-pressure box body is connected with a waste gas recovery tank through an acid gas purification tank.

5. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 3, characterized in that: A pipeline interface is arranged on the acrylic clamp plate. The gas pipeline is connected with the pipeline interface.

6. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 1, characterized in that: A scanning switch used for controlling the scanner cover and a gas delivery switch used for controlling the acid gas delivery are further arranged.

7. A method for studying the dynamic dissolution rule of acid gas in a fracture, using the device for studying the dynamic dissolution rule of acid gas in a fracture according to any one of claims 1-6, characterized in that: The method comprises the following steps: In step one, a natural core with cracks or a complete core is taken. The core is sliced to form a core slice. A characteristic surface to be observed is selected. The core slice is fixed on the acrylic clamp plate. In step two, the acrylic clamp plate is installed in the high-temperature and high-pressure box body. The gas pipeline is connected with the pipeline interface. In step three, the sealing property of the acid gas delivery is tested. In step four, the position of the high-definition microscope is adjusted by the longitudinal adjusting frame, the transverse adjusting frame and the level under the condition that the scanner cover is opened. The high-definition microscope observes and records the characteristic surface of the core slice. In step five, the scanner cover is closed. The illumination is adjusted. The laser scanning is performed. In step six, the gas storage tank is opened. The acid gas flow rate is adjusted. The laser scanning is performed every 0.1 s according to the scanning parameters designed by the computer. The high-definition sample and the image data of the laser scanning are transmitted to the computer. Step seven, the experimenter operates the computer to retrieve the acid gas flow rate, temperature and pressure, retrieve the images under the corresponding conditions, generate image files, analysis reports and logs.

Images