Experimental device and method for salt water-evaporation precipitation in rock fracture

Abstract

The invention discloses an experimental device and method for salt water-evaporation precipitation in rock fractures, and relates to the technical field of carbon dioxide sequestration, the experimental device for salt water-evaporation precipitation in rock fractures comprises a liquid storage structure, a fracture model, a gas storage structure, a shooting structure and a waste liquid collection structure, the liquid storage structure is used for storing liquid, the gas storage structure is used for storing gas, a fracture surface is arranged in the fracture model, the liquid storage structure and the gas storage structure are both connected with an inlet cavity of the fracture model, an outlet cavity of the fracture model is connected with the waste liquid collection structure, and the shooting structure is used for shooting the fracture model. The invention provides an experimental device and method for salt water-evaporation precipitation in rock fractures, which can realize real-time observation of dynamic evolution of salt water-precipitation in rock fractures and quantitative analysis.

Description

Technical Field

[0001] The invention relates to the technical field of carbon dioxide storage, and in particular to a salt water-evaporation precipitation experimental device and method in rock fissures. Background Art

[0002] As the global climate change problem becomes increasingly serious, CO2 capture and storage (CCS) technology is widely regarded as a key measure to mitigate the rising concentration of greenhouse gases in the atmosphere. In CCS technology, CO2 injection into deep saline aquifers is one of the important storage methods. However, despite the huge emission reduction potential of this technology, it still faces several key technical challenges in practical applications, especially the salt precipitation caused by the evaporation of saline water during CO2 injection, which has a significant impact on the permeability of underground reservoirs. When CO2 is injected into a deep reservoir containing saline water, the dry CO2 gas flow triggers the evaporation of saline water. As the salts in the saline water (such as NaCl, CaCl2, MgCl2, etc.) reach saturation concentration, the salts will precipitate and deposit in the pores and cracks of the reservoir. This salt precipitation will change the pore structure of the reservoir, causing blockage of pores or cracks, significantly reducing the permeability of the reservoir, and thus affecting the continuous injection capacity of CO2. This process not only affects the storage efficiency, but may also lead to increased formation pressure and increase geological risks. Therefore, in-depth understanding and mastery of the evolution mechanism of salt precipitation process, especially the dynamic evolution in complex rock fracture systems, is of great significance for optimizing CO2 geological storage technology and improving storage efficiency.

[0003] Traditional experimental methods make it difficult to achieve real-time observation and quantification of the dynamic processes of saline water evaporation and salt precipitation in complex fracture networks. Summary of the invention

[0004] The purpose of the present invention is to provide a salt water-evaporation precipitation experimental device and method in rock fissures to solve the problems existing in the above-mentioned prior art and to achieve real-time observation and quantitative analysis of the dynamic evolution of salt water-precipitation in rock fissures.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] The invention provides a salt water-evaporation precipitation experimental device in rock fissures, comprising: a liquid storage structure, a fissure model, a gas storage structure, a shooting structure and a waste liquid collection structure, wherein the liquid storage structure is used to store a salt water solution, the gas storage structure is used to store gas, a fissure surface is arranged in the fissure model, the liquid storage structure and the gas storage structure are both connected to an inlet cavity of the fissure model, an outlet cavity of the fissure model is connected to the waste liquid collection structure, and the shooting structure is used to shoot the fissure model.

[0007] Preferably, the saline solution stored in the liquid storage structure contains a dye.

[0008] Preferably, a stirring structure is provided in the liquid storage structure, and a pump and a valve are provided on the pipeline connecting the liquid storage structure and the inlet cavity of the fracture model.

[0009] Preferably, a filter and a mass flow controller are provided on the pipeline connecting the gas storage structure and the inlet cavity of the fracture model.

[0010] Preferably, the crack model is a transparent structure.

[0011] Preferably, the fracture model is made of transparent resin material and is manufactured by 3D printing, and the fractures in the fracture model have the same morphology as real rock fractures.

[0012] Preferably, the crack model is arranged on a workbench, a transparent window is arranged at a position of the workbench corresponding to the crack model, and a flat light source is arranged below the workbench at a position corresponding to the transparent window.

[0013] Preferably, the shooting structure is a camera, the shooting structure is located above the crack model, and the shooting structure is electrically connected to a computer.

[0014] Preferably, the inlet cavity of the fracture model is provided with an inlet pressure sensor and / or an inlet flow sensor, and the outlet cavity of the fracture model is provided with an outlet pressure sensor and / or an outlet flow sensor.

[0015] The present invention also provides an experimental method using the salt water-evaporation precipitation experimental device in rock fissures, comprising the following steps:

[0016] S1: Make a crack model;

[0017] S2: connecting the liquid storage structure, the fracture model, the gas storage structure and the waste liquid collection structure, and adjusting the distance between the shooting structure and the fracture model;

[0018] S3: introducing a saline solution into the fracture model through the liquid storage structure to ensure that the pipeline between the liquid storage structure and the fracture model and the fractures in the fracture model are saturated with saline, introducing gas into the fracture model through the gas storage structure, and the gas enters the fracture model to discharge part of the saline solution in the fracture model, and continuously introducing gas into the fracture model until the saline retained in the fracture model evaporates to form salt precipitation. In this process, the distribution of the saline, salt precipitation and gas in the fracture model is recorded by the shooting structure, and the pressure of the inlet and outlet of the fracture model is monitored at the same time;

[0019] S4: The experiment ends when the saline solution in the fracture model is completely dry.

[0020] Compared with the prior art, the present invention has achieved the following technical effects:

[0021] The present invention uses a fracture model and a shooting structure to track the entire process of salt water evaporation, salt precipitation formation and blockage in real time, making up for the defect that the existing technology cannot realize the dynamic evolution observation of salt precipitation in complex fractures. The present invention can accurately control experimental conditions such as flow rate and pressure to ensure the consistency and reliability of experimental results. At the same time, the device cost is relatively low, which is suitable for repeated experiments and expands the scope of experimental data collection. The present invention can observe and quantitatively analyze the dynamic process of salt precipitation in rock fractures in real time, which can comprehensively improve the understanding of salt precipitation phenomena in processes such as CO2 geological storage and groundwater management, and provide new technical means for optimizing reservoir injection strategies and improving reservoir management efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the salt water-evaporation precipitation experimental device in rock fissures of the present invention;

[0024] Figure 2 It is a schematic diagram of the crack model of the present invention;

[0025] In the figure: 1-inlet chamber, 2-outlet chamber, 3-crack surface, 4-liquid storage structure, 5-computer, 6-pump, 7-valve, 8-three-way valve, 9-inlet pressure sensor, 10-outlet pressure sensor, 11-waste liquid collection structure, 12-transparent window, 13-flat light source, 14-workbench, 15-mass flow controller, 16-filter, 17-gas storage structure, 18-stirring structure, 19-crack model, 20-shooting structure. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] The purpose of the present invention is to provide a salt water-evaporation precipitation experimental device and method in rock fissures to solve the problems existing in the above-mentioned prior art and to achieve real-time observation and quantitative analysis of the dynamic evolution of salt water-precipitation in rock fissures.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Embodiment 1

[0030] like Figure 1 to Figure 2 As shown, this embodiment provides a saltwater-evaporation-precipitation experimental device in rock fissures, including: a liquid storage structure 4, a fracture model 19, a gas storage structure 17, a shooting structure 20 and a waste liquid collection structure 11, wherein the liquid storage structure 4 is used to store a saltwater solution, the gas storage structure 17 is used to store gas, a fracture surface 3 is provided in the fracture model 19, the liquid storage structure 4 and the gas storage structure 17 are both connected to the inlet cavity 1 of the fracture model 19, the outlet cavity 2 of the fracture model 19 is connected to the waste liquid collection structure 11, and the shooting structure 20 is used to shoot the fracture model 19. This embodiment realizes real-time visual observation of the whole process of saltwater-evaporation-precipitation through a transparent fracture model 19 and a high-resolution shooting structure 20, and solves the problem that the fluid dynamics inside a complex fracture are difficult to quantify. In addition, this embodiment overcomes the problem of insufficient control accuracy of the traditional experimental system through precisely controlled flow rate, gas injection and pressure drop measurement, and can flexibly adjust the experimental parameters to ensure the repeatability and accuracy of the experimental results. Compared with the high cost and complex operation of CT or NMR technology, this embodiment adopts a modular design, which is easy to operate and low in cost. It is suitable for large-scale experiments and engineering applications, and improves the experimental efficiency and the feasibility of popularization and application.

[0031] Specifically, in this embodiment, the salt water solution stored in the liquid storage structure 4 contains dye, and a stirring structure 18 is provided in the liquid storage structure 4; the gas in the gas storage structure 17 is CO2.

[0032] In this embodiment, the inlet cavity 1 of the fracture model 19 is provided with a three-way valve 8, a pump 6 and a valve 7 are provided on the pipeline between the liquid storage structure 4 and the three-way valve 8, the pump 6 is preferably an ISCO pump or a peristaltic pump, and a filter 16 and a mass flow controller 15 are provided on the pipeline between the gas storage structure 17 and the three-way valve 8. The liquid storage structure 4, the pump 6, the valve 7, the gas storage structure 17, the filter 16 and the mass flow controller 15 constitute an injection control system, which can simulate the CO2 injection process under different flow rate conditions, thereby inducing salt water evaporation and salt precipitation. By switching the three-way valve 8, it is convenient to switch between the injection of salt water solution and the injection of gas, ensuring the flexibility and diversity of the experiment.

[0033] In this embodiment, the inlet cavity 1 of the fracture model 19 is provided with an inlet pressure sensor 9 and / or an inlet flow sensor, and the outlet cavity 2 of the fracture model 19 is provided with an outlet pressure sensor 10 and / or an outlet flow sensor; the fracture model 19 is made of a transparent resin material, and the fracture model 19 is made by 3D printing, and the fracture surface 3 in the fracture model 19 is the same as the real rock fracture morphology. This embodiment can not only accurately simulate the complex geometric morphology of natural fractures, but also realize the dynamic observation of the fluid inside the fracture. This embodiment uses the inlet pressure sensor 9 and the outlet pressure sensor 10 to monitor the pressure drop of the inlet and outlet as a measure of the effect of salt precipitation on the permeability of the fracture. The use of the inlet flow sensor and the outlet flow sensor can more directly reflect the obstruction of the flow of salt precipitation in the fracture, and provide more accurate fluid movement data.

[0034] In this embodiment, the crack model 19 is set on the workbench 14. A transparent window 12 is set at a position corresponding to the crack model 19 on the workbench 14. The transparent window 12 is made of glass. A flat light source 13 is set below the workbench 14 at a position corresponding to the transparent window 12.

[0035] In this embodiment, the shooting structure 20 is a camera, preferably a CCD camera. The shooting structure 20 is located above the fracture model 19. The shooting structure 20 is electrically connected to the computer 5. The shooting structure 20 and the computer 5 constitute a real-time imaging analysis system. Through the camera, the inlet pressure sensor 9 and the outlet pressure sensor 10, the fluid distribution, precipitation position and pressure drop changes in the salt water-evaporation-salt precipitation process are recorded in real time, providing high-resolution experimental data support, and providing a direct basis for quantitative analysis of the effect of salt precipitation in fractures on permeability. This embodiment uses relatively low-cost optical imaging technology to achieve accurate observation of complex fracture networks. The device is easy to operate and is suitable for large-scale engineering applications and research needs in industrial environments.

[0036] The pipeline connection, model fixation and imaging adjustment of the salt water-evaporation precipitation experimental device in rock fissures of this embodiment all adopt modular design, which is convenient for experimental operation and implementation of repeatable experiments.

[0037] The core of the saltwater-evaporation precipitation experimental device in rock fissures of this embodiment is the combination of a transparent fissure model 19, a high-precision injection control system and a real-time imaging analysis system. The transparent fissure model 19 uses 3D printing technology to simulate the geometric complexity of natural rock fissures. The injection control system can simulate the CO2 injection process under different flow rate conditions through a precise flow control device, thereby inducing saltwater evaporation and salt precipitation. The real-time imaging analysis system records the dynamic evolution of salt precipitation inside the fissure through a high-resolution CCD camera, and combines optical imaging technology to accurately quantify the salt precipitation distribution and permeability changes at different positions in the fissure.

[0038] This embodiment can simulate and observe in real time the salt precipitation process caused by the evaporation of salt water in rock fissures. Through the salt water-evaporation precipitation experimental device in rock fissures of this embodiment, researchers can accurately control the experimental conditions (such as flow rate, pressure, temperature, etc.), and capture the formation and evolution of salt precipitation and its impact on the permeability of the fissures in real time through the high-precision shooting structure 20. This device not only solves the technical problem that the dynamic evolution process of salt precipitation is difficult to observe in real time, but also provides an innovative platform for studying fissure fluid dynamics, salt precipitation patterns and their impact on reservoir performance.

[0039] Embodiment 2

[0040] This embodiment provides an experimental method using the salt water-evaporation precipitation experimental device in rock fissures of the first embodiment, comprising the following steps:

[0041] S1: Making a fracture model 19: Using a 3D scanner to obtain the surface morphology data of a real rock fracture, using 3Dmax or CATIA to construct a fracture 3D model, using 3D printing technology to form a fracture model 19 including an inlet cavity 1, an outlet cavity 2 and a transparent fracture surface 3. Compared with traditional water-stopping methods such as gluing or bolting, the 3D printed fracture model 19 has better air tightness;

[0042] S2: Pipe connection: Light blue (Macklin E808678, 0.125g / L) is added to the liquid storage structure 4 as a blue dye to dye the transparent saline solution to obtain a better imaging effect. The stirring structure 18 is turned on to continuously and automatically stir the saline solution injected into the liquid storage structure 4 to prevent the saline solution from being left standing for a long time and causing density stratification. The liquid storage structure 4 is connected to the pump 6 through a pipeline, and then connected to the three-way valve 8 through a valve 7. The other end of the three-way valve 8 is the gas storage structure 17 connected to the filter 16 through a pipeline, and then continues to be connected to the mass flow controller 15 through a pipeline, and finally connected to the three-way valve 8. The third end of the three-way valve 8 is connected to the inlet pressure sensor 9 through a pipeline, and then connected to the inlet cavity 1 of the fracture model 19. The outlet cavity 2 of the fracture model 19 is connected to the outlet pressure sensor 10 through a pipeline. The outlet pressure sensor 10 is connected to the waste liquid collection structure 11, that is, the connection of the pipeline is completed; Imaging quality adjustment: connect the computer 5 and the camera, turn on the flat light source 13, adjust the focal length and exposure time of the camera, and the working distance between the camera and the fracture model 19. After the image is clear, the imaging quality adjustment process is completed;

[0043] S3: Conduct a visualized salt water-evaporation precipitation experiment in rock fractures: First, close the end of the three-way valve 8 connected to the mass flow meter, open the pump 6 and the valve 7, and the pump 6 injects salt water into the fracture model 19 to ensure that the pipeline between the liquid storage structure 4 and the fracture model 19 and the fracture surface 3 in the fracture model 19 are saturated with salt water. Switch the three-way valve 8 to connect the gas storage structure 17 with the fracture model 19. The gas enters the fracture model 19 from the gas storage structure 17 through the filter 16 and the mass flow controller 15 in sequence. By adjusting the mass flow controller 15, the gas is injected into the fracture model 19 at different flow rates; the gas invades the fracture model 19 and replaces part of the salt water solution in the fracture to achieve the discharge of part of the salt water solution. After the gas breaks through, the continuous injection of gas causes the water in the residual salt water solution to evaporate, and salt precipitation begins. In this process, the dynamic evolution of salt water, salt precipitation and gas distribution is recorded by the camera, and the pressure drop is measured by the inlet pressure sensor 9 and the outlet pressure sensor 10, which can reflect the change of fracture permeability during the evaporation of the salt water solution.

[0044] S4: When the saline solution in the fracture model 19 is completely dry, the experiment ends.

[0045] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A salt water-evaporation precipitation experimental device in rock fissures, characterized by: include: A liquid storage structure, a fracture model, a gas storage structure, a photographing structure and a waste liquid collection structure, wherein the liquid storage structure is used to store a saline solution, the gas storage structure is used to store gas, a fracture surface is provided in the fracture model, the liquid storage structure and the gas storage structure are both connected to the inlet cavity of the fracture model, the outlet cavity of the fracture model is connected to the waste liquid collection structure, and the photographing structure is used to photograph the fracture model.

2. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The salt water solution stored in the liquid storage structure contains dye.

3. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1 is characterized in that: The liquid storage structure is provided with a stirring structure, and a pump and a valve are provided on a pipeline connecting the liquid storage structure and the inlet cavity of the fracture model.

4. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: A filter and a mass flow controller are arranged on the pipeline connecting the gas storage structure and the inlet cavity of the fracture model.

5. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The crack model is a transparent structure.

6. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The fracture model is made of transparent resin material and is manufactured by 3D printing. The fractures in the fracture model have the same morphology as real rock fractures.

7. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The crack model is arranged on a workbench, a transparent window is arranged at a position of the workbench corresponding to the crack model, and a flat light source is arranged at a position below the workbench corresponding to the transparent window.

8. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The shooting structure is a camera, which is located above the crack model and is electrically connected to a computer.

9. The salt water-evaporation precipitation experimental device in rock fissures according to claim 1, characterized in that: The inlet cavity of the fracture model is provided with an inlet pressure sensor and / or an inlet flow sensor, and the outlet cavity of the fracture model is provided with an outlet pressure sensor and / or an outlet flow sensor.

10. An experimental method using the salt water-evaporation precipitation experimental device in rock fissures according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1: Make a crack model; S2: connecting the liquid storage structure, the fracture model, the gas storage structure and the waste liquid collection structure, and adjusting the distance between the shooting structure and the fracture model; S3: introducing a saline solution into the fracture model through the liquid storage structure to ensure that the pipeline between the liquid storage structure and the fracture model and the fractures in the fracture model are saturated with saline, introducing gas into the fracture model through the gas storage structure, and the gas enters the fracture model to discharge part of the saline solution in the fracture model, and continuously introducing gas into the fracture model until the saline retained in the fracture model evaporates to form salt precipitation. In this process, the distribution of the saline, salt precipitation and gas in the fracture model is recorded by the shooting structure, and the pressure of the inlet and outlet of the fracture model is monitored at the same time; S4: The experiment ends when the saline solution in the fracture model is completely dry.

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