Lignite sample and manufacturing method and device thereof

Abstract

The invention discloses a lignite sample and a manufacturing method and device thereof. According to the manufacturing device and method of the lignite sample, the lignite sample is wound with the transparent heat-insulating adhesive tape, and the transparent heat-insulating adhesive tape is embedded and cured into the epoxy resin capable of providing a certain confining pressure condition, so that a long-term stable sealing visual environment with confining pressure is provided for the lignite sample. Meanwhile, the hard epoxy resin shell solves the problem that the loose and brittle lignite sample is difficult to transport on a bumpy mountain road, and the transparent heat insulation adhesive tape and the epoxy resin provide good observation conditions without damaging a sealed environment for subsequent core description. And the cured epoxy resin with confining pressure tightly wraps the lignite rock sample, so that the vibration influence during drilling of the small rock sample can be reduced, and the drilling success rate of the small rock sample of the loose and brittle lignite rock sample is greatly improved. And finally, the cured epoxy resin shell is removed in a melting manner, so that the operation is convenient, and the influence on the physicochemical properties of the lignite sample can be avoided.

Description

Technical Field

[0001] The invention relates to a lignite sample and a preparation method and device thereof. Background Art

[0002] The recoverable coalbed methane resources contained in lignite are as high as 4.96×10 12 m 3 . Affected by the characteristics of lignite such as low metamorphism, low compaction, stress sensitivity and easy water loss and oxidation, the coal rock currently drilled to the ground usually expands, oxidizes and cracks in a short period of time, causing its mechanical properties, pore-crack characteristics and adsorption / desorption laws, which are key parameters involved in coalbed methane development, to be very different from those in situ underground, and are seriously distorted, making it difficult to scientifically guide production practices. In order to avoid the rapid distortion of lignite after it leaves the underground environment, it must be initially processed and made into specific coal samples when sampling on site, so as to achieve the purpose of long-term fidelity, convenient transportation and convenient secondary processing and sample preparation.

[0003] There are three main sampling methods at present: 1. Wrapping with plastic wrap; 2. Wax sealing; 3. Canning in gas cans, but all of them have obvious shortcomings. First, none of the three methods can provide effective confining pressure to limit the expansion and cracking of coal samples after decompression. Secondly, the sealing of method one is limited and can only delay the occurrence of dehydration and oxidation; although method two can provide good sealing conditions, it is impossible to observe the selected sections during subsequent processing and sampling; method three is not conducive to large-scale use, and in the subsequent processing and sampling, the coal samples must be taken out in advance, resulting in a certain degree of distortion in the processing process. Summary of the invention

[0004] In order to at least partially solve any of the above technical problems, an embodiment of the present invention provides a device and method for making high-fidelity lignite samples. Under the premise of ensuring the high fidelity of the lignite samples, it is not only easy to transport, but also convenient for secondary processing and sample preparation, thereby reducing distortion during the processing.

[0005] As one aspect of the present invention, it relates to a method for preparing a lignite sample, the method comprising the following steps:

[0006] S1. Selection and pretreatment of rock samples

[0007] Select the target section lignite rock sample, conduct a water immersion test, dry the surface, and obtain the target section lignite rock sample;

[0008] Evenly wrap the target lignite rock sample with a transparent heat-insulating tape, and install several metal racks according to the length of the rock sample after wrapping to obtain the target lignite rock sample after pretreatment;

[0009] S2. Fixing of lignite rock sample packaging tube

[0010] A mold release agent is applied to the inner surface of the lignite rock sample packaging tube, and the pre-treated target lignite rock sample obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube;

[0011] After placing the support frame into the threaded end at the bottom of the lignite rock sample packaging tube, the lignite rock sample packaging tube is erected and fixedly connected to the lower sealing shell;

[0012] S3. Packaging of rock samples

[0013] Pour a mixture of liquid epoxy resin and curing agent into the lignite rock sample packaging cylinder and immerse the pretreated target lignite rock sample to complete the packaging;

[0014] S4. Assembly device

[0015] Assemble the upper sealing shell and the lower sealing shell to form a sealed chamber;

[0016] The temperature and air pressure in the stable sealed chamber are within the set range. After the epoxy resin is completely cured, the upper sealed shell is opened, the lignite rock sample packaging cylinder is taken out, and the lignite sample is obtained after ventilation and curing.

[0017] In one or some optional embodiments, in S1, the step of selecting a target section of lignite rock sample, performing a water immersion test, and drying the surface to obtain the target section of lignite rock sample comprises:

[0018] Taking out the lignite rock samples from the coring barrel, sorting and numbering them;

[0019] After observing and describing the lignite rock sample, a target section is selected or the entire lignite rock sample is used as the target section;

[0020] The target section lignite rock sample is placed in clean water to conduct a core water immersion test, while removing surface mud and debris;

[0021] After the target section lignite rock sample stops violently emitting gas, it is taken out from the clean water, and the water stains on the surface of the target section lignite rock sample are fully wiped off to obtain the target section lignite rock sample.

[0022] In one or some optional embodiments, in S1, the transparent heat-insulating tape is used to evenly wrap the target lignite rock sample, and a plurality of metal frames are installed according to the length of the rock sample after wrapping to obtain the pre-treated target lignite rock sample, including:

[0023] The transparent heat-insulating tape is used to evenly wrap the target section of lignite rock sample with the surface water stains wiped off, ensuring that the target section of lignite rock sample is completely wrapped without being exposed; and then, according to the length of the target section of lignite rock sample, a certain number of radially centered metal frames are installed to ensure that the target section of lignite rock sample does not tilt in the lignite rock sample packaging tube.

[0024] In one or some optional embodiments, in S2, applying a release agent on the inner surface of the lignite rock sample packaging tube, and pushing the pretreated target lignite rock sample obtained in S1 into the horizontally placed lignite rock sample packaging tube, comprises:

[0025] A release agent is applied to the inner surface of the lignite rock sample packaging tube, and the pretreated target lignite rock sample obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube, keeping the inner diameter of the lignite rock sample packaging tube larger than the outer diameter of the pretreated target lignite rock sample.

[0026] In one or some optional embodiments, in S3, pouring the mixture of liquid epoxy resin and curing agent into the lignite rock sample packaging cylinder and immersing the lignite rock sample to complete the packaging includes:

[0027] The liquid epoxy resin and the curing agent are fully stirred in a set ratio, and then poured into the lignite rock sample packaging tube, and the liquid level is kept higher than the length of the target section of the pretreated lignite rock sample.

[0028] In one or some optional embodiments, in S4, the temperature and air pressure in the stable sealed chamber are within a set range, including:

[0029] An air compressor, an air heater, a pressure-limiting valve and a pressure gauge are used to stabilize the air pressure in the sealed chamber at a target air pressure, and the target air pressure is close to the in-situ confining pressure underground of the lignite rock sample.

[0030] In one or some optional embodiments, the method further comprises: obtaining a lignite sample;

[0031] The lignite sample is obtained by soaking the lignite sample in a solvent, and after the cured epoxy resin is dissolved, the lignite rock sample can be completely taken out from the cured epoxy resin.

[0032] As another aspect of the present invention, it relates to a lignite sample, which is prepared by the above-mentioned preparation method.

[0033] As another aspect of the present invention, it relates to a device for making the above-mentioned lignite sample, the device comprising: an upper sealed shell, a lower sealed shell, a lignite sample packaging cylinder, a pressure gauge, a pressure limiting valve, an air compressor and an air heater;

[0034] The upper sealed shell and the lower sealed shell form a sealed chamber, and the sealed chamber is used to contain the lignite rock sample packaging cylinder;

[0035] The lignite rock sample packaging tube is connected to the lower sealing shell through threads and is used to place the lignite sample;

[0036] The pressure gauge is installed on the upper sealed housing and is used to observe the pressure change in the sealed chamber;

[0037] The pressure limiting valve is arranged in the lower sealing housing and is used to adjust the pressure in the sealing chamber;

[0038] The air heater is arranged on the lower sealed shell and connected to the air compressor.

[0039] In one or some optional embodiments, it further includes: a rubber ring, which is arranged at the connection between the lignite rock sample packaging tube and the lower sealing shell to form a closed structure.

[0040] In one or some optional embodiments, it further includes: a support frame, which is arranged at the bottom of the lignite rock sample packaging cylinder and is used to support the lignite rock sample.

[0041] In one or some optional embodiments, it further includes: a metal frame, which is radially arranged in the lignite rock sample packaging tube and is used to clamp and center the lignite sample.

[0042] The device and method for making lignite samples proposed in the present invention provide a long-term stable sealed visual environment with confining pressure for lignite rock samples by wrapping transparent heat-insulating tape around the lignite rock samples and embedding the tape inside epoxy resin that can provide determined confining pressure conditions after curing. At the same time, the hard epoxy resin shell solves the problem of difficult transportation of brittle lignite rock samples on bumpy mountain roads. The transparent heat-insulating tape and epoxy resin provide good observation conditions for subsequent core description without destroying the sealed environment. The cured epoxy resin with confining pressure tightly wraps the lignite rock samples, which can reduce the impact of vibration when drilling small rock samples and greatly improve the success rate of drilling small rock samples of brittle lignite rock samples. Finally, the cured epoxy resin shell is removed by dissolving, which is not only convenient but also can avoid affecting the physical and chemical properties of the lignite rock samples.

[0043] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the structure of a lignite sample preparation device provided in Example 1 of the present invention;

[0045] Figure 2 A schematic diagram of the lignite rock sample packaging tube and metal frame structure provided by the present invention;

[0046] In the attached Figure 1 , 2In the figure: 1. Upper sealing shell; 2. Lower sealing shell; 3. Pressure limiting valve; 4. Pressure gauge; 5. Air compressor; 6. Air heater; 7. Lignite rock sample packaging cylinder; 8. Metal frame; 9. Support frame; 10. Rubber ring; 11. Target lignite rock sample after pretreatment. DETAILED DESCRIPTION

[0047] In the following description, specific details such as specific structures and technologies are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application can also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0048] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0049] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0050] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0051] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0052] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0053] It should be understood that the size of the serial numbers of the steps in the following embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0054] In order to illustrate the technical solution of the present application, a specific embodiment is provided below for illustration.

[0055] Embodiment 1

[0056] See attached Figure 1 , 2 This embodiment provides a lignite sample preparation device, comprising: an upper sealed shell 1, a lower sealed shell 2, a pressure limiting valve 3, a pressure gauge 4, an air compressor 5, an air heater 6 and a lignite rock sample packaging tube 7;

[0057] The upper sealed shell 1 and the lower sealed shell 2 form a sealed chamber, and the sealed chamber is used to contain the lignite rock sample packaging tube 7;

[0058] The lignite rock sample packaging tube 7 is connected to the lower sealing shell 2 through threads and is used to place the lignite sample;

[0059] The pressure gauge 4 is installed on the upper sealed housing 1 and is used to observe the pressure change in the sealed chamber;

[0060] The pressure limiting valve 3 is arranged in the lower sealing housing 2, and is used to adjust the pressure in the sealing chamber;

[0061] The air heater 6 is disposed on the lower sealed shell 2 and connected to the air compressor 5 .

[0062] In the embodiment of the present invention, it further comprises: a rubber ring 10, which is arranged at the connection between the lignite rock sample packaging tube 7 and the lower sealing shell 2 to form a closed structure.

[0063] In the embodiment of the present invention, it further comprises: a support frame 9, which is arranged at the bottom of the lignite rock sample packaging tube 7 and is used to support the pre-treated target lignite rock sample 11.

[0064] In the embodiment of the present invention, a metal frame 8 is further included. The metal frame 8 is radially arranged in the lignite rock sample packaging tube 7 and is used to clamp and center the pre-treated target lignite rock sample 11.

[0065] In order to enable those skilled in the art to more clearly and intuitively understand the production device of the present invention, a further description is given. It should be noted that in this description, the connection method and connection order of the device cannot become limitations of the present invention.

[0066] In a specific embodiment, the lignite sample preparation device of the present invention comprises an upper sealed shell 1 and a lower sealed shell 2 to form a sealed chamber, the upper sealed shell 1 is equipped with a pressure gauge 4, wherein the pressure gauge 4 can be installed on the top of the upper sealed shell 1 or on the side of the upper sealed shell 1 according to actual needs, and the pressure gauge 4 is used to observe the pressure change in the sealed chamber;

[0067] The lower sealed housing 2 is externally connected to a pressure limiting valve 3, an air compressor 5 and an air heater 6, wherein the installation positions of the pressure limiting valve 3, the air compressor 5 and the air heater 6 can be adjusted accordingly according to actual conditions; the pressure limiting valve 3 is used to regulate the pressure in the sealed chamber in real time; the air compressor 5 provides the target air pressure in the sealed chamber; the air heater 6 is used to maintain the temperature in the sealed chamber;

[0068] A threaded slot is provided inside the lower sealed shell 2, and the lignite rock sample packaging tube 7 is screwed into the threaded slot to be threadedly connected with the lower sealed shell 2, wherein the connection between the interior of the lower sealed shell 2 and the lignite rock sample packaging tube 7 can be through a threaded connection, or can be replaced by other connection methods;

[0069] A rubber ring 10 is used to provide sealing for the lower sealing shell 2 and the lignite rock sample packaging tube 7. A metal frame 8 is placed inside the lignite rock sample packaging tube 7, and a support frame 9 is placed at the bottom. The metal frame 8 and the support frame 9 are used to center the pretreated target segment lignite rock sample 11. In order to further avoid direct contact between the pretreated target segment lignite rock sample 11 and the inner wall of the lignite rock sample packaging tube 7, which affects the local packaging quality, the inner diameter of the lignite rock sample packaging tube 7 is kept larger than the outer diameter of the pretreated target segment lignite rock sample 11.

[0070] Embodiment 2

[0071] Based on the same inventive concept, this embodiment provides a method for preparing a lignite sample, comprising the following steps:

[0072] S1. Selection and pretreatment of rock samples

[0073] Select the target section lignite rock sample, conduct a water immersion test, dry the surface, and obtain the target section lignite rock sample;

[0074] Use a transparent heat-insulating tape to evenly wrap the target lignite rock sample, and according to the length of the rock sample after wrapping, install a number of metal frames 8 to obtain the target lignite rock sample 11 after pretreatment;

[0075] S2. Fixing of lignite rock sample packaging tube

[0076] A mold release agent is applied to the inner surface of the lignite rock sample packaging tube 7, and the target lignite rock sample 11 obtained in S1 after pretreatment is pushed into the horizontally placed lignite rock sample packaging tube 7;

[0077] After the support frame 9 is placed into the threaded end at the bottom of the lignite rock sample packaging tube 7, the lignite rock sample packaging tube 7 is erected and fixedly connected to the lower sealing shell 2;

[0078] S3. Packaging of rock samples

[0079] Pour a mixture of liquid epoxy resin and curing agent into the lignite rock sample packaging tube 7 and immerse the pretreated target lignite rock sample 11 to complete the packaging;

[0080] S4. Assembly device

[0081] Assemble the upper sealing shell 1 and the lower sealing shell 2 to form a sealed chamber;

[0082] The temperature and air pressure in the stable sealed chamber are within the set range. After the epoxy resin is completely cured, the upper sealed shell 1 is opened, and the lignite rock sample packaging tube 7 is taken out. After ventilation and curing, the lignite sample 11 is obtained.

[0083] In the embodiment of the present invention, if it is necessary to process multiple target segment lignite rock samples, only S1 to S2 need to be repeated for each target segment lignite rock sample, and the total processing time does not exceed 10 minutes. After all lignite rock sample packaging tubes 7 are fixedly connected to the lower sealing shell 2, S3 is repeated uniformly, and finally S4 is performed to obtain multiple lignite samples.

[0084] In the embodiment of the present invention, in S1, the step of selecting a target section of lignite rock sample, performing a water immersion test, and drying the surface to obtain the target section of lignite rock sample comprises:

[0085] Taking out the lignite rock samples from the coring barrel, sorting and numbering them;

[0086] After observing and describing the lignite rock sample, a target section is selected or the entire lignite rock sample is used as the target section;

[0087] The target section lignite rock sample is placed in clean water to conduct a core water immersion test, while removing surface mud and debris;

[0088] After the target section lignite rock sample stops violently emitting gas, it is taken out from the clean water, and the water stains on the surface of the target section lignite rock sample are fully wiped off to obtain the target section lignite rock sample.

[0089] In the embodiment of the present invention, in S1, the transparent heat-insulating tape is used to evenly wrap the target lignite rock sample, and a plurality of metal frames 8 are installed according to the length of the rock sample after wrapping to obtain the pre-treated target lignite rock sample 11, including:

[0090] The target segment lignite rock sample with the surface water stains wiped off is evenly wrapped with the transparent heat-insulating tape to ensure that the target segment lignite rock sample is completely wrapped without being exposed; and then, according to the length of the target segment lignite rock sample, a certain number of radially centered metal frames 8 are installed to ensure that the pre-treated target segment lignite rock sample 11 does not tilt in the lignite rock sample packaging tube 7.

[0091] In a specific embodiment, the transparent heat-insulating tape blocks 300°C / h, and the temperature rise of the target lignite rock sample wrapped by the wrapped tape does not exceed 25°C.

[0092] In the embodiment of the present invention, in S2, the step of applying a release agent on the inner surface of the lignite rock sample packaging tube 7 and pushing the pretreated target lignite rock sample 11 obtained in S1 into the horizontally placed lignite rock sample packaging tube 7 comprises:

[0093] A release agent is applied to the inner surface of the lignite rock sample packaging tube 7, and the pretreated target lignite rock sample 11 obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube 7, keeping the inner diameter of the lignite rock sample packaging tube 7 larger than the outer diameter of the pretreated target lignite rock sample 11.

[0094] In a specific embodiment, a release agent is applied to the inner surface of the lignite rock sample packaging tube 7, and the pretreated target segment lignite rock sample 11 obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube 7, keeping the inner diameter of the lignite rock sample packaging tube 7 2 cm larger than the outer diameter of the pretreated target segment lignite rock sample 11.

[0095] In the embodiment of the present invention, in S3, the mixture of liquid epoxy resin and curing agent is poured into the lignite rock sample packaging tube 7 and immersed in the pretreated target lignite rock sample 11 to complete the packaging, including:

[0096] The liquid epoxy resin and the curing agent are fully stirred in a set ratio, and then poured into the lignite rock sample packaging tube 7 , and the liquid level is kept higher than the length of the target lignite rock sample 11 after pretreatment.

[0097] In a specific embodiment, the liquid epoxy resin and the curing agent are fully stirred in a ratio of 2:1, and then poured into the lignite rock sample packaging tube 7, and the liquid level is kept 1 cm above the upper end of the pretreated target lignite rock sample 11.

[0098] In an embodiment of the present invention, in S4, the temperature and air pressure in the stable sealed chamber are within a set range, including: using an air compressor 5, a pressure limiting valve 3 and a pressure gauge 4 to stabilize the air pressure in the sealed chamber at a target air pressure, wherein the target air pressure is close to the in-situ confining pressure underground of the lignite rock sample, and using an air heater 6 to control the temperature in the sealed chamber to the optimal temperature for curing of the epoxy resin.

[0099] In a specific embodiment, the air pressure in the sealed chamber is regulated to the in-situ confining pressure of the lignite rock sample underground by using an air compressor 5, a pressure limiting valve 3 and a pressure gauge 4; the temperature in the sealed chamber is controlled at about 35°C by using an air heater 6, so that the internal temperature of the epoxy resin does not rise by more than 200°C during the curing process of the mixture of the liquid epoxy resin and the curing agent; after stabilizing the temperature and air pressure in the sealed chamber for 15 to 30 minutes, the epoxy resin is initially cured.

[0100] In the embodiment of the present invention, it also includes: obtaining a lignite sample; the obtaining of the lignite sample means: immersing the lignite sample in a solvent, and after the cured epoxy resin is dissolved, the pre-treated target lignite rock sample 11 can be completely taken out from the cured epoxy resin.

[0101] In a specific embodiment, the immersion time is adjusted according to actual conditions, and the immersion can be completed as long as the cured epoxy resin is melted.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may also be combined, the steps may be implemented in any order, and there are many other changes in different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a lignite sample, characterized in that: The method comprises the following steps: S1. Selection and pretreatment of rock samples Select the target section lignite rock sample, conduct a water immersion test, dry the surface, and obtain the target section lignite rock sample; Evenly wrap the target lignite rock sample with a transparent heat-insulating tape, and install several metal racks according to the length of the rock sample after wrapping to obtain the target lignite rock sample after pretreatment; S2. Fixing of lignite rock sample packaging tube A mold release agent is applied to the inner surface of the lignite rock sample packaging tube, and the pre-treated target lignite rock sample obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube; After placing the support frame into the threaded end at the bottom of the lignite rock sample packaging tube, the lignite rock sample packaging tube is erected and fixedly connected to the lower sealing shell; S3. Packaging of rock samples Pour a mixture of liquid epoxy resin and curing agent into the lignite rock sample packaging cylinder and immerse the pretreated target lignite rock sample to complete the packaging; S4. Assembly device Assemble the upper sealing shell and the lower sealing shell to form a sealed chamber; The temperature and air pressure in the stable sealed chamber are within the set range. After the epoxy resin is completely cured, the upper sealed shell is opened, the lignite rock sample packaging cylinder is taken out, and the lignite sample is obtained after ventilation and curing.

2. The method for preparing the lignite sample according to claim 1, characterized in that: In S1, the step of selecting a target section lignite rock sample, conducting a water immersion test, and drying the surface to obtain the target section lignite rock sample comprises: Taking out the lignite rock samples from the coring barrel, sorting and numbering them; After observing and describing the lignite rock sample, a target section is selected or the entire lignite rock sample is used as the target section; The target section lignite rock sample is placed in clean water to conduct a core water immersion test, while removing surface mud and debris; After the target section lignite rock sample stops violently emitting gas, it is taken out from the clean water, and the water stains on the surface of the target section lignite rock sample are fully wiped off to obtain the target section lignite rock sample.

3. The method for preparing the lignite sample according to claim 1, characterized in that: In S1, the transparent heat-insulating tape is used to evenly wrap the target lignite rock sample, and several metal frames are installed according to the length of the rock sample after wrapping to obtain the pre-treated target lignite rock sample, including: The transparent heat-insulating tape is used to evenly wrap the target section of lignite rock sample with the surface water stains wiped off, ensuring that the target section of lignite rock sample is completely wrapped without being exposed; and then, according to the length of the target section of lignite rock sample, a certain number of radially centered metal frames are installed to ensure that the target section of lignite rock sample does not tilt in the lignite rock sample packaging tube.

4. The method for preparing a lignite sample according to claim 1, characterized in that: In S2, the release agent is applied to the inner surface of the lignite rock sample packaging tube, and the pre-treated target lignite rock sample obtained in S1 is pushed into the horizontal lignite rock sample packaging tube, including: A release agent is applied to the inner surface of the lignite rock sample packaging tube, and the pretreated target lignite rock sample obtained in S1 is pushed into the horizontally placed lignite rock sample packaging tube, keeping the inner diameter of the lignite rock sample packaging tube larger than the outer diameter of the pretreated target lignite rock sample.

5. The method for preparing a lignite sample according to claim 1, characterized in that: In S3, the mixture of liquid epoxy resin and curing agent is poured into the lignite rock sample packaging cylinder and immersed in the pretreated target lignite rock sample to complete the packaging, including: The liquid epoxy resin and the curing agent are fully stirred in a set ratio, and then poured into the lignite rock sample packaging tube, and the liquid level is kept higher than the length of the target section of the pretreated lignite rock sample.

6. The method for preparing a lignite sample according to claim 1, characterized in that: In S4, the temperature and pressure in the stable sealed chamber are within a set range, including: An air compressor, an air heater, a pressure-limiting valve and a pressure gauge are used to stabilize the air pressure in the sealed chamber at a target air pressure, and the target air pressure is close to the in-situ confining pressure underground of the lignite rock sample.

7. The method for preparing a lignite sample according to claim 1, characterized in that: The method further comprises: obtaining a lignite sample; The lignite sample is obtained by soaking the lignite sample in a solvent, and after the cured epoxy resin is dissolved, the lignite rock sample can be completely taken out from the cured epoxy resin.

8. A lignite sample, characterized in that: The lignite sample is prepared by the lignite sample preparation method according to any one of claims 1 to 7.

9. A device for preparing the lignite sample as claimed in claim 8, characterized in that: The manufacturing device comprises: an upper sealing shell, a lower sealing shell, a lignite rock sample packaging cylinder, a pressure gauge, a pressure limiting valve, an air compressor and an air heater; The upper sealed shell and the lower sealed shell form a sealed chamber, and the sealed chamber is used to contain the lignite rock sample packaging cylinder; The lignite rock sample packaging tube is connected to the lower sealing shell through threads and is used to place the lignite sample; The pressure gauge is installed on the upper sealed housing and is used to observe the pressure change in the sealed chamber; The pressure limiting valve is arranged in the lower sealing housing and is used to adjust the pressure in the sealing chamber; The air heater is arranged on the lower sealed shell and connected to the air compressor.

10. The device for preparing a lignite sample according to claim 9, characterized in that: Also includes: Rubber ring, The rubber ring is arranged at the connection between the lignite rock sample packaging tube and the lower sealing shell to form a closed structure.

11. The device for preparing a lignite sample according to claim 9, characterized in that: Also includes: Support frame, The support frame is arranged at the bottom of the lignite rock sample packaging tube and is used for supporting the lignite rock sample.

12. The device for preparing a lignite sample according to claim 9, characterized in that: Also includes: Metal rack, The metal frame is radially arranged in the lignite rock sample packaging tube for clamping and centering the lignite sample.

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