Device and method for researching dynamic corrosion rule of acid gas in crack

Abstract

The invention discloses a device and method for researching the dynamic corrosion law of acid gas in a crack, and belongs to the field of acid gas corrosion experiments in oil and gas field development, and the device comprises a stratum acidification simulation structure which is used for fixing a rock core slice and simulating a high-temperature and high-pressure environment; the laser image scanning structure is used for performing high-DPI color scanning on the rock core slices; the high-definition microscopic structure is used for providing a high-definition microscopic image of a multi-dimensional observation rock core slice; the acid gas circulation structure is used for conveying acid gas to the rock core slices and carrying out acid gas flow rate control, acid gas purification and waste gas recovery; and the computer is used for receiving the transmitted experimental data and analyzing and processing the experimental data. According to the device, a high-temperature and high-pressure stratum environment is simulated, acid gas is conveyed to a rock core slice, and dynamic acquisition of experimental data of acid gas dissolution is realized through cooperation of a high-definition microstructure and a laser image scanning structure.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of acid gas corrosion experiment in oil and gas field development, and particularly relates to a device and method for researching dynamic acid gas corrosion law in fractures. BACKGROUND

[0002] In the fields of oil and gas field development, geothermal resource utilization and CO2 geological storage, the interaction mechanism of gas and rock fractures is a core problem affecting the efficiency and safety of engineering. However, the existing technology still has significant limitations in the research on the acid gas corrosion law in fractures. Traditional experiments are mostly based on homogeneous rock samples or simple pore structures, and use methods such as measuring permeability after static soaking to characterize the effect, and can only measure macroscopic parameters before and after corrosion.

[0003] Currently, the equipment and method for measuring surface characteristics are relatively mature, but most of them are limited to post-experiment measurement and macroscopic parameter characterization, lacking real-time detection of parameters during the experiment. The evaluation of dynamic acid gas corrosion characteristics is still missing. Rock surface corrosion characteristics, surface roughness, and acid gas microflow characteristics can greatly affect the effect of reservoir acidification reconstruction, but the real-time characterization method of these parameters is not perfect, and there is a lack of strict evaluation index. SUMMARY

[0004] The purpose of the present application is to provide a device and method for researching dynamic acid gas corrosion law in fractures, which simulates a controllable high temperature and high pressure formation environment, continuously delivers acid gas to the core slice, and realizes dynamic acquisition of acid gas corrosion experiment data through high-definition microscopic structure and laser image scanning structure.

[0005] To achieve the above purpose, the present application provides a device for researching dynamic acid gas corrosion law in fractures, comprising a formation acidification simulation structure for installing and fixing a core slice and simulating a high temperature and high pressure environment to perform acid gas corrosion core section observation experiment; a laser image scanning structure for high DPI color scanning of the core slice; a high-definition microscopic structure for providing high-definition microscopic images of the core slice in multiple dimensions; an acid gas circulation structure for delivering acid gas to the core slice, controlling acid gas flow rate, purifying acid gas and recovering waste gas; a computer for controlling the formation acidification simulation structure, the laser image scanning structure, the acid gas circulation structure, the temperature and pressure detection and control structure, and connecting with each structure through a line, receiving and transmitting experimental data, and analyzing and processing the experimental data.

[0006] Preferably, the stratum acidification simulation structure comprises a high-temperature and high-pressure box for pressurizing and warming the high-temperature and high-pressure environment of the simulated stratum, and a top end of the high-temperature and high-pressure box is provided with an acrylic clamp plate, a core slice is fixed at a center of the acrylic clamp plate, and both sides of the acrylic clamp plate are connected with the high-temperature and high-pressure box through sealing rubber sleeves.

[0007] Preferably, the laser image scanning structure comprises a scanner cover for illuminating and scanning the experimental object, and the scanner cover is arranged above the acrylic clamp plate and hinged to the high-temperature and high-pressure box.

[0008] Preferably, the high-definition microscopic structure comprises a high-definition electron microscope for shooting high-definition sample images of the core slice in the experiment, and the high-definition electron microscope is arranged on an adjusting assembly for adjusting the height and horizontal position of the high-definition electron microscope, and a level meter is arranged on the high-definition electron microscope for adjusting the high-definition electron microscope to be horizontal.

[0009] Preferably, 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 electron microscope, and the transverse adjusting frame is used for adjusting the horizontal position of the high-definition electron microscope.

[0010] Preferably, the acid gas circulation structure comprises a gas storage tank, the gas storage tank is connected with the high-temperature and high-pressure box through a high-pressure-resistant gas pipeline, and a gas dryer and a flow controller are arranged on the gas pipeline, and the gas dryer and the flow controller are used for drying the gas and controlling the gas flow through the pipeline.

[0011] Preferably, the high-temperature and high-pressure box is connected with a waste gas recovery tank through an acid gas purification tank.

[0012] Preferably, a pipeline interface is arranged on the acrylic clamp plate, and the gas pipeline is connected with the pipeline interface.

[0013] Preferably, the method further comprises a scanning switch for controlling the scanner cover and a gas delivery switch for controlling the acid gas delivery.

[0014] The application provides a method for researching the dynamic dissolution law of acid gas in a fracture, comprising the following steps: Step one, taking a natural core with a fracture or a complete core, slicing the core to obtain a core slice (the complete core needs to be fractured (artificially manufactured fracture) and then spliced), and selecting a characteristic surface to be observed, and fixing the core slice on an acrylic clamp plate; Step two, installing the acrylic clamp plate in a high-temperature and high-pressure box, and connecting a gas pipeline with a pipeline interface; Step three, testing the sealing property of acid gas delivery; Step four, under the condition that the scanning machine cover is opened, the position of the high-definition microscope is adjusted through the longitudinal adjustment frame support, the horizontal adjustment frame and the level, so that the high-definition microscope observes and records the characteristic surface of the core slice; Step five, the scanning machine cover is closed, the illumination is adjusted, and the laser scanning is performed; Step six, the gas storage tank is opened, the acid gas flow rate is adjusted, the scanning parameters are designed through the computer, the laser scanning is performed every 0.1 s and recorded, and the high-definition sample image collected by the high-definition microscope and the image data of the laser scanning are transmitted to the computer; Step seven, the experimental personnel operate the computer to call the acid gas flow rate, temperature and pressure, call the image under the corresponding condition, generate the image file, analysis report and log.

[0015] Therefore, the device and method for researching the dynamic dissolution rule of acid gas in a fracture have the following beneficial effects: 1. The device integrates the laser image scanning structure and the high-definition microscope structure, solves the problem of observing the static effect after acidification, realizes dynamic observation by transmitting the laser image and high-definition image in the experimental process in real time, and observes the change characteristics in the experimental process; 2. The laser image scanning structure captures the dynamic evolution of the three-dimensional topography of the rock surface in the acidification process at a high frequency, combines the high-definition image of the high-definition microscope structure, realizes full-scale dynamic monitoring from macro roughness change to micro pore structure evolution, and can accurately capture the transient interface behavior of the acid gas diffusion front; 3. The acrylic plate is detachably designed in a modular manner, can adapt to core slice samples of different sizes, and can generate a comprehensive evaluation report containing three-dimensional topography reconstruction and pore network evolution parameters in cooperation with the computer, the high-definition microscope structure and the laser image scanning structure; 4. The device in the application has the advantages that the gas storage tank is connected with a gas pipeline, is easy to replace, has adjustable acid gas flow rate, adjustable magnification and position of the high-definition electronic microscope, and replaceable core slice, the experimental conditions are easy to control, and observation of various types of experiments can be realized.

[0016] The technical solutions of the application will be further described in detail below with reference to the drawings and embodiments. DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the device for researching the dynamic dissolution rule of acid gas in a fracture in the embodiment of the application. Figure 2 It is a schematic diagram of the acrylic plate structure in the embodiment of the application. Figure 3 It is a schematic diagram of the pipeline interface structure in the embodiment of the application. Figure 4A high-definition electron microscope observation sample chart of an embodiment of the present application; Figure 5 A gray scale chart of a high-definition electron microscope observation sample of an embodiment of the present application; Figure 6 A laser scanning chart of an embodiment of the present application.

[0018] In the figure: 1, gas tank; 2, gas pipeline; 3, gas drying and flow controller; 4, longitudinal adjusting frame; 5, transverse adjusting frame; 6, high-definition electron microscope; 7, level meter; 8, scanning machine cover; 9, computer; 10, scanning switch; 11, gas delivery switch; 12, line; 13, high-temperature and high-pressure box; 14, acid gas purification box; 15, waste gas recovery tank; 16, sealing rubber sleeve; 17, core slice; 18, acrylic splint; 19, pipeline interface. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the embodiments of the present application are further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present application and not to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present application. Examples of the embodiments are shown in the drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout.

[0020] It should be noted that the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or server comprising a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0021] Similar reference signs and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0022] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0023] In the description of the present application, it is also necessary to explain that, unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection" should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or integrally connected; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0024] As shown in Figure 1 The device for researching the dynamic dissolution law of acid gas in cracks according to the present application comprises a formation acidification simulation structure, a laser image scanning structure, a high-definition microscopic structure, an acid gas circulation structure, a temperature and pressure detection and control structure, and a computer 9.

[0025] The formation acidification simulation structure is used for installing and fixing the core slice 17 and simulating a high-temperature and high-pressure environment to perform acid gas dissolution core slice observation experiments. The formation acidification simulation structure comprises a high-temperature and high-pressure box 13, which adopts an existing full-transparent high-temperature and high-pressure reaction kettle for pressurizing and heating to simulate a high-temperature and high-pressure environment of a formation. As shown in Figure 2 The top end of the high-temperature and high-pressure box 13 is provided with a plexiglass clamp plate 18, and the core slice 17 is fixed at the center of the plexiglass clamp plate 18 (only needs to be simply fixed and placed, does not slip off, and does not need to seal the core slice 17, and the angle is not changed during the experiment process, and is almost not displaced after being placed horizontally). The two sides of the plexiglass clamp plate 18 are connected with the high-temperature and high-pressure box 13 through sealing rubber sleeves 16. Different core slices 17 can be self-defined and installed in the plexiglass clamp plate 18. The high-temperature and high-pressure box 13 can measure and control the change of temperature and pressure during the experiment process.

[0026] The laser image scanning structure is used for high-DPI color scanning of the core slice 17. The laser image scanning structure comprises a scanner cover 8 for illuminating and scanning the experimental object. The scanner cover 8 is arranged above the plexiglass clamp plate 18, and one side of the scanner cover 8 is hingedly connected with the high-temperature and high-pressure box 13. The scanner cover 8 adopts an existing printer scanner cover.

[0027] The high-definition microstructure is used for providing high-definition micro images of the core slice 17 for multi-dimensional observation of the core slice 17, and for observing the pore structure of the core slice 17 in detail. The high-definition microstructure comprises a high-definition electron microscope 6 used for shooting high-definition micro images of the core slice 17 in the experiment, and the high-definition electron microscope 6 is arranged on an adjusting assembly. The adjusting assembly is used for adjusting the height and horizontal position of the high-definition electron microscope 6, and a level 7 is arranged on the high-definition electron microscope 6 and used for adjusting the high-definition electron microscope 6 to be horizontal. The adjusting assembly comprises a longitudinal adjusting frame 4 and a transverse adjusting frame 5, the longitudinal adjusting frame 4 is used for adjusting the height and horizontal position of the high-definition electron microscope 6, and the transverse adjusting frame 5 is used for adjusting the horizontal position of the high-definition electron microscope 6. The longitudinal adjusting frame 4 and the transverse adjusting frame 5 of the adjusting assembly adopt existing XY two-dimensional moving platforms, and the level 7 adopts an existing device.

[0028] The acid gas circulation structure is used for delivering acid gas to the core slice 17, controlling the flow rate of the acid gas, purifying the acid gas and recovering waste gas. The acid gas circulation structure comprises a gas storage tank 1, the gas storage tank 1 is connected with a high-temperature and high-pressure box body 13 through a high-pressure resistant gas pipeline 2, a gas dryer and a flow controller 3 are arranged on the gas pipeline 2, the gas dryer and the flow controller 3 are used for drying the gas and controlling the flow rate of the gas flowing through the pipeline, and the gas dryer and the flow controller 3 adopt an existing structure. The high-temperature and high-pressure box body 13 is connected with a waste gas recovery tank 15 through an acid gas purification tank 14 (the acid gas purification tank 14 adopts an existing acid gas purification device, and the acid gas purification tank 14 in the embodiment is a sealed water tank). As shown in FIG. 1, a pipeline interface 19 is arranged on a plexiglass clamp plate 18, and the gas pipeline 2 is connected with the pipeline interface 19. The gas pipeline 2 needs to use a steel high-pressure displacement pipeline. Figure 3

[0029] The device for researching the dynamic dissolution rule of the acid gas in the fracture further comprises a scanning switch 10 used for controlling the scanning machine cover 8 and a gas delivery switch 11 used for controlling the delivery of the acid gas.

[0030] The computer 9 is used for controlling each structure of the layer acidification simulation structure, the laser image scanning structure, the acid gas circulation structure, the temperature and pressure detection and control structure, and is electrically connected with each structure (including the scanning switch 10 and the gas delivery switch 11) through a line 12 in an existing manner. The computer is further used for receiving and analyzing and processing the experimental data.

[0031] The method for researching the dynamic dissolution rule of the acid gas in the fracture comprises the following steps. Step one, taking a natural core with a fracture or a complete core, slicing the core to obtain a core slice 17 (the complete core needs to be fractured (artificially manufactured fracture) and then spliced), and selecting a characteristic surface to be observed, and fixing the core slice 17 on a plexiglass clamp plate.

[0032] ​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.

[0033] 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.

[0034] 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.

[0035] Step 5: Close the scanner cover 8, adjust the lighting, and perform laser scanning.

[0036] 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.

[0037] Step 7: The experimenter uses computer 9 to retrieve acid flow rate, temperature, and pressure, retrieves images under the corresponding conditions, generates image files, and produces analysis reports and logs.

[0038] The same method is used for cores of different sizes; repeat the steps described above.

[0039] The above experimental methods yielded the following results. Figures 4-6 : 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.

[0040] 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.

[0041] 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 and 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. 2.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 1, characterized in that: 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. 3.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 2, characterized in that: 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.

4. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 1, characterized in that: 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.

5. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 4, 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. 6.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 2, 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.

7. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 6, 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. 8.The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 6, characterized in that: A pipeline interface is arranged on the acrylic clamp plate. The gas pipeline is connected with the pipeline interface.

9. The device for researching the dynamic dissolution rule of acid gas in cracks according to claim 2, 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.

10. 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 1-9, 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 support, 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