Method and device for quantitatively characterizing the proportion of closed pores in shale

Abstract

The present invention provides a method and apparatus for quantitatively characterizing the proportion of closed pores in shale. The method comprises: obtaining the original weight and the weight after drying of a shale sample, and determining the water content of the shale sample under formation water-bearing conditions based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under formation water-bearing conditions; obtaining the volume of the total gas storage space of the dried shale sample; obtaining the volume of the recoverable gas storage space of the shale sample under formation water-bearing conditions; determining the closed pore proportion of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample, and using the closed pore proportion of the shale sample as the closed pore proportion of the target shale. The recoverable gas storage space volume and the capillary closed pore space volume of the shale under the environmental humidity corresponding to the formation water-bearing conditions are obtained, providing technical support for quantitatively evaluating the recoverability of shale under such environmental humidity.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploration, and particularly relates to a method and device for quantitatively characterizing the proportion of closed pores in shale. Background Art

[0002] Shale gas is a natural gas resource that can be mined and stored in shale layers. It is a clean and efficient unconventional natural gas resource. China has large recoverable reserves of shale gas.

[0003] Shale, as a fine-grained sedimentary rock, undergoes certain burial conditions and corresponding diagenesis, resulting in a pore structure dominated by micro- and nanopores. Furthermore, the pore network and its connectivity become highly complex, controlled by the complex organic and inorganic mineral composition and wettability of shale. With the deepening of shale gas research, there is an urgent need to improve the flow and production capacity of shale gas by analyzing the occurrence characteristics of fluids (gas and water) in shale pores. Shale pores can be roughly viewed as a tree-like, multi-level bifurcated structure. Because gas and water coexist in reservoir spaces dominated by micro- and nanopores, shale pores exhibit capillary confinement, low-velocity diffusion, and surface adsorption, characteristics that are significantly different from conventional reservoirs. These characteristics are fundamental to studying shale gas connectivity and flow capacity and are key to influencing its microscopic preservation capacity. Previous researchers used water vapor adsorption-desorption technology to establish water vapor adsorption isotherms at different relative humidity at constant temperature to describe the storage behavior of adsorbed water. SANS and USANS were used to respond to the fluid components filled in the pores, thereby analyzing the storage capacity of shale matrix pores for fluids with different dynamic radii (mainly methane, water, carbon dioxide, etc.).

[0004] When bound water accumulates in shale pores, it occupies a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores in shale, bound water can occupy the throats of these smaller pores, forming a certain degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. Different shale types are governed by differences in pore structure and distribution, resulting in varying degrees of capillary closure.

[0005] Therefore, there is an urgent need for a method that can quantitatively characterize the proportion of capillary closed pores to help analyze the extent of hydrocarbon gas production in shale. Summary of the Invention

[0006] To solve the technical problem, the present invention provides a method and device for quantitatively characterizing the proportion of closed pores in shale, so as to quantitatively characterize the proportion of closed pores of capillaries in shale.

[0007] The first aspect of the present invention provides a method for quantitatively characterizing the proportion of closed pores in shale, the method comprising: obtaining the original weight and the weight after drying of the shale sample, and determining the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation; obtaining the volume of the total gas storage space of the dried shale sample; obtaining the volume of the recoverable gas storage space of the shale sample under water-bearing conditions in the formation; determining the closed pore proportion of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and using the closed pore proportion of the shale sample as the closed pore proportion of the target shale.

[0008] In one embodiment, obtaining the weight of the dried shale sample includes drying the shale sample at a temperature of 105° C. to 120° C. for more than 24 hours.

[0009] In one embodiment, obtaining the volume of the total gas storage space of the dried shale sample includes: obtaining the volume of the total gas storage space of the dried shale sample using a nitrogen adsorption method.

[0010] In one embodiment, the volume of the recoverable gas storage space of a shale sample under formation water-bearing conditions is determined according to the following steps: the dried shale sample is placed in an environment with a specified humidity, so that the shale sample has the same water content as under formation water-bearing conditions when it is in water vapor adsorption equilibrium, and the volume of the recoverable gas storage space of the shale sample at this time is obtained; wherein, the specified humidity is determined by the following steps: water vapor adsorption experiments are conducted on parallel samples of the shale sample at different environmental humidities to determine the maximum water content of the parallel samples at different environmental humidities; based on the maximum water content of the parallel samples at different environmental humidities, a fitting method is used to determine the corresponding relationship between the maximum water content and the environmental humidity; based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-bearing conditions.

[0011] In one embodiment, obtaining the volume of recoverable gas storage space of the shale sample includes: obtaining the volume of recoverable gas storage space of the shale sample using a nitrogen adsorption method.

[0012] In one embodiment, before conducting water vapor adsorption experiments on parallel samples of the shale sample under different ambient humidity conditions, the method further includes: crushing the parallel samples so that the particle size of the crushed parallel samples ranges from 20 to 40 meshes.

[0013] In one embodiment, water vapor adsorption experiments are conducted on parallel samples of the shale sample at different ambient humidity, including: the adsorption experiment time is controlled within 24 hours to 48 hours until the parallel samples reach an adsorption equilibrium state.

[0014] In one embodiment, after determining the water content of the shale sample and before obtaining the volume of the total gas storage space of the dried shale sample, the method further includes: crushing the shale sample so that the particle size of the crushed shale sample ranges from 20 to 40 meshes.

[0015] In one embodiment, the closed pore ratio of the shale sample is determined based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, including: determining the water volume of the shale sample based on the water content of the shale sample; taking the difference between the volume of the total gas storage space of the shale sample and the volume of the recoverable gas storage space and the water volume as the closed pore volume of the shale sample; and taking the ratio of the closed pore volume to the volume of the total gas storage space as the closed pore ratio of the shale sample.

[0016] In a second aspect, the present application provides a device for quantitatively characterizing the proportion of closed pores in shale, comprising: a water content determination module for obtaining the original weight and the weight after drying of the shale sample, and determining the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation; a first volume determination module for obtaining the volume of the total gas storage space of the dried shale sample; a second volume determination module for obtaining the volume of the recoverable gas storage space of the shale sample under water-bearing conditions in the formation; a calculation module for determining the closed pore proportion of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and taking the closed pore proportion of the shale sample as the closed pore proportion of the target shale.

[0017] In a third aspect, the present application provides a storage medium having program code stored therein. When the program code is executed by a processor, the method for quantitatively characterizing the proportion of closed pores in shale as described above is implemented.

[0018] In a fourth aspect, the present application provides a computer device comprising: a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, the method for quantitatively characterizing the proportion of closed pores in shale as described above is implemented.

[0019] The method of quantitatively characterizing the proportion of closed pores in shale of the present invention is applied to quantitatively characterize the proportion of closed pores in shale based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample. The proportion of closed pores in shale under different irreducible water storage conditions can be obtained, thereby providing technical support for quantitatively evaluating the recoverability of shale under burial conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which constitute a part of the present application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 A flow chart showing a method for quantitatively characterizing the proportion of closed pores in shale according to one embodiment of the present invention is shown.

[0022] Figure 2 A schematic structural diagram of an apparatus for quantitatively characterizing the proportion of closed pores in shale according to an embodiment of the present invention is shown.

[0023] Figure 3 A flow chart showing a method for quantitatively characterizing the proportion of closed pores in shale according to a specific embodiment of the present invention is shown. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the present invention more clear, the following detailed description of the embodiments of the present invention is provided in conjunction with the accompanying drawings and examples. This will enable a full understanding of how the present invention applies technical means to solve technical problems and achieve corresponding technical effects, and to implement the invention accordingly. The embodiments of the present invention and the various features therein may be combined with each other as long as they do not conflict with each other, and the resulting technical solutions are all within the scope of protection of the present invention.

[0025] The present invention provides a method, device, storage medium and electronic device for quantitatively characterizing the proportion of closed pores in shale. By obtaining the water content or water content of the shale sample, since the density of water is 1g / cm 3 , then the value of water content is the volume of water in shale, and the value of water content is the volume of water per unit mass (per gram) of dry shale; the volume of the total gas storage space of the dried shale sample is obtained by nitrogen adsorption method; for the parallel samples of the shale sample, the corresponding relationship between water content and humidity or the corresponding relationship between water content and humidity is determined; based on the corresponding relationship, the humidity corresponding to the water content of the shale sample or the humidity corresponding to the water content of the shale sample is determined, and then the water vapor adsorption experiment is carried out on the shale sample at the humidity until the Once the shale sample reaches adsorption equilibrium, a water-containing sample is obtained, and the volume of the recoverable gas storage space in the water-containing sample is determined using nitrogen adsorption. Finally, the volume of the capillary-enclosed pore space per unit mass (per gram) of the shale sample is determined based on the total gas storage space volume, the recoverable gas storage volume, and the water content or moisture content. The capillary-enclosed pore ratio of the shale sample is further determined and used as the capillary-enclosed pore ratio of the target shale. This provides technical support for quantitatively evaluating the recoverability of shale under actual burial conditions.

[0026] Example 1

[0027] This embodiment provides a method for quantitatively characterizing the proportion of closed pores in shale. Figure 1 The flowchart of the method for quantitatively characterizing the proportion of closed pores in shale according to one embodiment of the present invention is shown. Figure 1 As shown, the method of this embodiment may include the following steps:

[0028] S100: Obtaining the original weight and the weight after drying of the shale sample, and determining the water content of the shale sample under formation water-bearing conditions based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under formation water-bearing conditions.

[0029] The water content of the shale sample is determined according to the following steps:

[0030] S101. Obtain the original weight of the shale sample as G0.

[0031] S102. Dry the shale sample under high temperature conditions, and obtain a weight of the dried shale sample as G1.

[0032] Preferably, when the shale sample is dried, the shale sample is dried at a temperature of 105° C. to 120° C. for more than 24 hours.

[0033] S103. Subtract the weight after drying G1 from the original weight G0 to obtain the water content W of the shale sample. The water content W of the shale sample can be obtained by the following expression:

[0034] W=G0-G1.

[0035] S200: Obtaining the volume of the total gas storage space of the dried shale sample.

[0036] Specifically, before obtaining the volume of the total gas storage space of the dried shale sample, the shale sample may be crushed so that the particle size of the crushed shale sample is in the range of 20 to 40 meshes.

[0037] Specifically, the nitrogen adsorption method can be used to obtain the total gas storage space volume of the dried shale sample, and the obtained total gas storage space volume is recorded as P0. The total gas storage space volume P0 represents the volume of all pores contained in the dried shale sample. In this embodiment, it is equivalent to the volume of nitrogen adsorbed by all pores in the dried shale sample.

[0038] The nitrogen adsorption method refers to the physical adsorption of nitrogen by shale in a liquid nitrogen environment. In this embodiment, the shale is fully adsorbed in the nitrogen environment until the shale reaches an adsorption equilibrium state.

[0039] S300: Obtain the volume of recoverable gas storage space of the shale sample under formation water-bearing conditions.

[0040] Specifically, the dried shale sample is placed in an environment with a specified humidity so that the shale sample has the same water content as under the formation water conditions when it is in water vapor adsorption equilibrium, and the volume of the recoverable gas storage space of the shale sample at this time is obtained.

[0041] The specified humidity can be determined according to the following steps:

[0042] S301. Conduct water vapor adsorption experiments on parallel samples of the shale sample at different ambient humidity to determine the maximum water content of the parallel samples at different ambient humidity.

[0043] The parallel sample in this embodiment refers to a shale sample that is under the same geological conditions and has the same properties as the shale sample. Preferably, the wax-sealed shale can be promptly divided into two equal shale samples after being unsealed.

[0044] Specifically, before conducting the water vapor adsorption experiment under different ambient humidity conditions, the parallel samples may be crushed so that the particle size of the crushed parallel samples ranges from 20 to 40 meshes.

[0045] Specifically, when conducting water vapor adsorption experiments under different ambient humidity conditions, the adsorption experiment time can be controlled within 24 hours to 48 hours until the shale sample reaches an adsorption equilibrium state.

[0046] S302. Determine the corresponding relationship between the maximum water content and the ambient humidity using a fitting method based on the maximum water content of the parallel samples under different ambient humidity conditions.

[0047] In one example, the GAB model is used to fit the maximum moisture content of parallel samples at different ambient humidity to determine the corresponding relationship between the maximum moisture content and the ambient humidity.

[0048] S303: Based on the corresponding relationship, determine the specified humidity according to the water content of the shale sample.

[0049] In one example, the volume of recoverable gas storage space in a shale sample can be obtained using a nitrogen adsorption method.

[0050] The volume of recoverable gas storage space of the shale sample is determined according to the following steps:

[0051] First, the shale sample is placed in the above-specified humidity environment and a water vapor adsorption experiment is performed on the shale sample. The adsorption experiment time can be controlled within 24 hours to 48 hours until the shale sample reaches an adsorption equilibrium state, thereby obtaining a water-containing sample of the shale sample.

[0052] Then, nitrogen adsorption experiments were conducted on the water-containing sample using the nitrogen adsorption method until the sample reached adsorption equilibrium. The volume of the recoverable gas storage space in the water-containing sample was obtained and recorded as P1. The volume of the recoverable gas storage space P1 represents the volume of the pore space remaining in the shale sample after deducting the volume of the closed pore space and the volume of water outside the closed pore space.

[0053] S400: Determine the closed pore ratio of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale.

[0054] The closed pore ratio of the shale sample can be determined specifically according to the following steps:

[0055] S401. Determine the water volume of the shale sample according to the water content of the shale sample.

[0056] Specifically, since the density of water is 1g / cm 3 When the unit of water content W is gram, the value of W is the volume occupied by water in shale (ml). 3 =1ml, if the water content W is 1g, then the volume of water is 1ml.

[0057] S402. The difference between the volume of the total gas storage space of the shale sample and the volume of the recoverable gas storage space and the water volume is taken as the closed pore volume of the shale sample. The closed pore volume can be obtained by the following expression:

[0058] P C =P0–P1–W

[0059] Among them, P C represents the closed pore volume in the shale sample, P0 represents the volume of the total gas storage space in the shale sample, P1 represents the volume of the recoverable gas storage space in the shale sample, and W represents the volume of water in the shale sample.

[0060] S403. The ratio of the closed pore volume to the total gas storage space volume is used as the closed pore ratio of the shale sample. The closed pore ratio in the shale can be obtained by the following expression:

[0061]

[0062] in, It is expressed as the proportion of closed pores in shale, which is the proportion of capillary closed pores in shale at the ambient humidity corresponding to the water content of the formation.

[0063] It should be noted that in this embodiment, the weight mentioned is in g, and the volume mentioned is in cm. 3 , of which 1cm 3 =1ml.

[0064] During actual oil and gas exploration, bound water accumulates in shale pores, occupying a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores in shale, bound water can occupy the throats of these smaller pores, creating a certain degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. Shale is governed by differences in pore structure and distribution, and the presence of bound water can result in varying degrees of capillary closure.

[0065] In this example, the water content of the shale sample is obtained. Since the density of water is 1g / cm 3 , the water content is the volume of water in the shale. The nitrogen adsorption method is used to obtain the volume of the total gas storage space of the dried shale sample. For parallel samples of the shale sample, the corresponding relationship between water content and humidity is determined. Based on this corresponding relationship, the humidity corresponding to the water content of the shale sample is determined. Then, a water vapor adsorption experiment is conducted on the shale sample at this humidity until the shale sample reaches adsorption equilibrium, obtaining a water-containing sample of the shale sample and the volume of the recoverable gas storage space of the water-containing sample. Finally, based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample, the volume of the capillary closed pore space in the shale sample is obtained. The capillary closed pore ratio of the shale sample is further determined and used as the capillary closed pore ratio of the target shale. This provides technical support for the quantitative assessment of the recoverability of shale under actual burial conditions.

[0066] Example 2

[0067] This embodiment provides a device for quantitatively characterizing the proportion of closed pores in shale. Figure 2 The schematic diagram of the structure of the device for quantitatively characterizing the proportion of closed pores in shale according to one embodiment of the present invention is shown. Figure 2 As shown, the device of this embodiment may include:

[0068] a water content determination module 510 for obtaining the original weight and the weight after drying of the shale sample, and determining the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation;

[0069] A first volume determination module 520 is configured to obtain the volume of the total gas storage space of the dried shale sample;

[0070] A second volume determination module 530 is used to obtain the volume of recoverable gas storage space of the shale sample under formation water-bearing conditions;

[0071] The calculation module 540 is used to determine the closed pore ratio of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale.

[0072] In this embodiment, the apparatus further includes a processor and a memory. When the program code in the memory is executed by the processor, the program code is configured to execute the following program modules: a water content determination module 510, a first volume determination module 520, a second volume determination module 530, and a calculation module 540, to implement the following method steps:

[0073] Obtain the original weight and the weight after drying of the shale sample, and determine the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation; obtain the volume of the total gas storage space of the dried shale sample; obtain the volume of the recoverable gas storage space of the shale sample under water-bearing conditions in the formation; determine the closed pore ratio of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale.

[0074] In one embodiment, obtaining the weight of the dried shale sample includes drying the shale sample at a temperature of 105° C. to 120° C. for more than 24 hours.

[0075] In one embodiment, obtaining the volume of the total gas storage space of the dried shale sample includes: obtaining the volume of the total gas storage space of the dried shale sample using a nitrogen adsorption method.

[0076] In one embodiment, the volume of the recoverable gas storage space of a shale sample under formation water-bearing conditions is determined according to the following steps: the dried shale sample is placed in an environment with a specified humidity, so that the shale sample has the same water content as under formation water-bearing conditions when it is in water vapor adsorption equilibrium, and the volume of the recoverable gas storage space of the shale sample at this time is obtained; wherein, the specified humidity is determined by the following steps: water vapor adsorption experiments are conducted on parallel samples of the shale sample at different environmental humidities to determine the maximum water content of the parallel samples at different environmental humidities; based on the maximum water content of the parallel samples at different environmental humidities, a fitting method is used to determine the corresponding relationship between the maximum water content and the environmental humidity; based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-bearing conditions.

[0077] In one embodiment, obtaining the volume of recoverable gas storage space of the shale sample includes: obtaining the volume of recoverable gas storage space of the shale sample using a nitrogen adsorption method.

[0078] In one embodiment, before conducting water vapor adsorption experiments on parallel samples of the shale sample under different ambient humidity conditions, the method further includes: crushing the parallel samples so that the particle size of the crushed parallel samples ranges from 20 to 40 meshes.

[0079] In one embodiment, water vapor adsorption experiments are conducted on parallel samples of the shale sample at different ambient humidity, including: the adsorption experiment time is controlled within 24 hours to 48 hours until the parallel samples reach an adsorption equilibrium state.

[0080] In one embodiment, after determining the water content of the shale sample and before obtaining the volume of the total gas storage space of the dried shale sample, the method further includes: crushing the shale sample so that the particle size of the crushed shale sample ranges from 20 to 40 meshes.

[0081] In one embodiment, the closed pore ratio of the shale sample is determined based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, including: determining the water volume of the shale sample based on the water content of the shale sample; taking the difference between the volume of the total gas storage space of the shale sample and the volume of the recoverable gas storage space and the water volume as the closed pore volume of the shale sample; and taking the ratio of the closed pore volume to the volume of the total gas storage space as the closed pore ratio of the shale sample.

[0082] The nitrogen adsorption method refers to the physical adsorption of nitrogen by shale in a liquid nitrogen environment. In this embodiment, the shale is fully adsorbed in the nitrogen environment until the shale reaches an adsorption equilibrium state.

[0083] It should be noted that in this embodiment, the weight mentioned is in g, and the volume mentioned is in cm. 3 , of which 1cm 3 =1ml.

[0084] In another possible embodiment, the device may further include a display module and a communication module. The display area can support touch operation and can intuitively display data such as humidity conditions, total gas storage space, recoverable gas storage space, shale water content and closed pore ratio at ambient humidity corresponding to formation water content, and a curve showing the relationship between water content and humidity conditions. The display module also includes a corresponding operation area, which provides a user interface in which the data can be saved to memory. The communication module can transmit this data to other smart terminal devices for subsequent further analysis and viewing. Smart terminal devices include electronic devices such as computers, mobile phones, and tablets.

[0085] In an embodiment, the storage medium may also include program code, data files, data structures, etc., alone or in combination. The storage medium or program code may be specifically designed and understood by a person skilled in the art of computer software, or the storage medium may be well known and available to a person skilled in the art of computer software. Examples of storage media include: magnetic media, such as hard disks, floppy disks, and tapes; optical media, such as CDROMs and DVDs; magneto-optical media, such as optical disks; and hardware devices, specifically configured to store and execute program code, such as read-only memory (ROM), random access memory (RAM), flash memory; or servers, app stores, etc. Examples of program code include machine code (e.g., code generated by a compiler) and files containing high-level code, which can be executed by a computer using an interpreter. In addition, the storage medium may be distributed in a networked computer system, and computer code or program code may be stored and executed in a decentralized manner. The processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components.

[0086] It should be noted that the device may include one or more processors and memory (i.e., computer-readable storage medium), and the processor and memory may be connected via a bus or other means. Memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile program code, non-volatile computer-executable program code, and modules. The processor executes various functional applications and data processing of the device by running the non-volatile software programs, program codes, and modules stored in the memory.

[0087] During actual oil and gas exploration, bound water accumulates in shale pores, occupying a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores in shale, bound water can occupy the throats of these smaller pores, creating a certain degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. Shale is governed by differences in pore structure and distribution, and the presence of bound water can result in varying degrees of capillary closure.

[0088] In this embodiment, the water content of the shale sample is determined by the water content determination module. Since the density of water is 1g / cm 3 , the water content is the volume of water in the shale. The first volume determination module uses nitrogen adsorption to determine the total gas storage space volume of the dried shale sample. The second volume determination module determines the correspondence between water content and humidity for a parallel sample of the same shale sample. Based on this correspondence, the humidity corresponding to the water content of the shale sample is determined. Then, a water vapor adsorption experiment is conducted on the shale sample at this humidity until the shale sample reaches adsorption equilibrium, obtaining a water-containing sample of the shale sample. The volume of the recoverable gas storage space of the water-containing sample is determined using nitrogen adsorption. Finally, the calculation module calculates the volume of the capillary closed pore space in the shale sample based on the total gas storage space volume, the recoverable gas storage space volume, and the water content. The capillary closed pore ratio of the shale sample is further determined and used as the capillary closed pore ratio of the target shale. This provides technical support for the quantitative assessment of the recoverability of shale under actual burial conditions.

[0089] Example 3

[0090] This embodiment provides a specific example. In this embodiment, the proportion of capillary closed pores in the Longmaxi Formation shale is quantitatively characterized. Figure 3 A flow chart illustrating a method for quantitatively characterizing the proportion of closed pores in shale according to a specific embodiment of the present invention is shown. The method of this embodiment may include the following steps:

[0091] The first step is to determine the water content of the shale sample.

[0092] Specifically, the water content of shale samples can be determined according to the following steps:

[0093] A wax-sealed Longmaxi Formation shale was selected. After unsealing, a shale sample of about 20 g was taken, and its original weight G0 was measured to be 20.005 g.

[0094] The shale sample was then dried at 105° C.-120° C. for more than 24 hours, and the weight G1 after drying was 19.955 g.

[0095] The water content of the Longmaxi Formation shale is obtained by subtracting the original weight G0 from the dried weight G1. The water content can be obtained by the following expression:

[0096] G W =(G0-G1)

[0097] Through the water content G W , and further obtain the water content W of the shale sample. The water content W can be obtained by the following expression:

[0098] W=(G W / G1)*100%

[0099] =((20.055-19.895) / 19.955)*100%

[0100] ≈0.8%

[0101] Among them, since the density of water is 1g / cm 3 , 1cm 3 =1ml. If the water content W is 1g, then the volume of water is 1ml.

[0102] According to the value of water content W, it can be known that the volume of water in each gram of the shale sample is about 0.008 ml.

[0103] The second step is to determine the water vapor adsorption curve of the shale sample.

[0104] Specifically, the water vapor adsorption curve of shale samples can be determined according to the following steps:

[0105] 1. The shale sample is crushed so that the particle size of the crushed shale sample is in the range of 20 to 40 meshes.

[0106] 2. 10g of shale samples were selected for adsorption experiments using the water vapor adsorption method. The adsorption time was controlled between 24 and 48 hours until the sample reached adsorption equilibrium. The humidity range was set between 0% and 98%, and the humidity interval was controlled within 5%. This yielded data on the relationship between the moisture content and humidity of the shale samples.

[0107] The third step is to use the fitting method to obtain the corresponding relationship between the moisture content and humidity of the shale samples based on the corresponding relationship data between the moisture content and humidity of the shale samples, and determine the humidity corresponding to a moisture content of 0.8% based on the corresponding relationship expression.

[0108] Specifically, the GAB model can be used to fit the corresponding relationship data between the water content and humidity of the shale sample to obtain a corresponding relationship curve between the water content and humidity.

[0109] Furthermore, based on the corresponding relationship curve between the water content and humidity of the shale, it is determined that the humidity corresponding to the water content W in the shale sample is 75%.

[0110] The fourth step is to crush the shale samples to obtain dry samples and water-containing samples.

[0111] Specifically, the crushed shale sample is divided into two equal parts, one part is dried to obtain a dry sample, and the other part is subjected to a water vapor adsorption experiment under a humidity condition of 75%. The adsorption time is controlled at 24h-48h until the parallel sample reaches an adsorption equilibrium state to obtain a water-containing sample.

[0112] The fifth step is to obtain the volume of the total gas storage space of the dry sample and the volume of the recoverable gas storage space of the water sample by using the nitrogen adsorption method based on the dry sample and the water sample.

[0113] Specifically, the volume P0 of the total gas storage space per unit mass (per gram) of the dry sample obtained by the nitrogen adsorption method is 0.0244 ml; the volume P1 of the recoverable gas storage space per unit mass (per gram) of the water-containing sample obtained by the nitrogen adsorption method is 0.0121 ml.

[0114] Among them, the volume of the total gas storage space represents: the total volume of all pores contained in the unit mass (per gram) of shale sample, in this embodiment, that is, the total volume of nitrogen adsorbed in all pores in the unit mass (per gram) of dry sample; the volume of the recoverable gas storage space represents: the volume of the remaining pore space after removing the volume of the closed pore space and the volume of water outside the closed pore space in the unit mass (per gram) of shale sample.

[0115] The nitrogen adsorption method refers to the physical adsorption of nitrogen by shale in a liquid nitrogen environment. In this embodiment, the shale is fully adsorbed in the nitrogen environment until the shale reaches an adsorption equilibrium state.

[0116] The sixth step is to determine the proportion of capillary closed pores in the shale sample based on the volume of the total gas storage space of the dry sample and the volume of the recoverable gas storage space and the water content of the water-containing sample.

[0117] Specifically, the capillary closed pore volume P is calculated based on the obtained total gas storage space volume P0, the recoverable gas storage space volume P1 and the water content W. C , capillary closed pore volume P C It can be obtained by the following expression:

[0118] P C =P0-P1–W

[0119] =0.0244-0.0121-0.008

[0120] =0.0043

[0121] Based on the capillary closed pore volume P C , further obtain the volume fraction of capillary closed pores, which can be obtained by the following expression:

[0122]

[0123] That is, when the ambient humidity of the Longmaxi Formation shale is 75%, the proportion of capillary closed pores is about 17.6%.

[0124] It should be noted that in this embodiment, the weight mentioned is expressed in g, and the volume mentioned is expressed in cm. 3 Indicates that 1cm 3 =1ml.

[0125] During actual oil and gas exploration, bound water accumulates in the pores of the Longmaxi Formation shale, occupying a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores within the Longmaxi Formation shale, bound water can occupy the pore throats within these smaller pores, creating a degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. The Longmaxi Formation shale is governed by differences in pore structure and distribution, resulting in varying degrees of capillary closure.

[0126] From the experimental data, it can be seen that the water content W of the Longmaxi Formation shale obtained in this embodiment is about 0.8%. Since the density of water is 1g / cm 3, the water content is the volume of water per unit mass of Longmaxi Formation shale, that is, the volume of water per unit mass of Longmaxi Formation shale (per gram) is 0.008ml. For parallel samples of this Longmaxi Formation shale, the corresponding relationship between water content and humidity was determined. Based on this corresponding relationship, the humidity corresponding to a water content of 0.8% was determined. For crushed Longmaxi Formation shale samples, dry and water-containing samples were obtained. Based on these dry and water-containing samples, the nitrogen adsorption method was used to determine the total gas storage space per unit mass (per gram) of the dry sample to be 0.0244ml, and the volume of recoverable gas storage space per unit mass (per gram) of the water-containing sample to be 0.0121ml. Based on the total gas storage space volume, recoverable gas storage space volume, and water volume per unit mass (per gram) of Longmaxi Formation shale, it was determined that the proportion of capillary closed pores in the Longmaxi Formation shale is approximately 17.6%. The purpose of quantitatively evaluating the proportion of capillary closed pores in the Longmaxi Formation shale was achieved, providing technical support for quantitatively evaluating the recoverability of gas storage in the Longmaxi Formation shale.

[0127] Example 4

[0128] Another aspect of the present invention provides a storage medium having a program code stored therein. When the program code is executed by a processor, the method for quantitatively characterizing the proportion of closed pores in shale as described above is implemented:

[0129] Obtain the original weight and the weight after drying of the shale sample, and determine the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation; obtain the volume of the total gas storage space of the dried shale sample; obtain the volume of the recoverable gas storage space of the shale sample under water-bearing conditions in the formation; determine the closed pore ratio of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale.

[0130] In one embodiment, obtaining the weight of the shale sample after drying includes: drying the shale sample at a temperature of 105° C. to 120° C. for more than 24 hours, and then obtaining the weight after drying.

[0131] In one embodiment, obtaining the volume of the total gas storage space of the dried shale sample includes: obtaining the volume of the total gas storage space of the dried shale sample using a nitrogen adsorption method.

[0132] In one embodiment, the volume of the recoverable gas storage space of a shale sample under formation water-bearing conditions is determined according to the following steps: the dried shale sample is placed in an environment with a specified humidity, so that the shale sample has the same water content as under formation water-bearing conditions when it is in water vapor adsorption equilibrium, and the volume of the recoverable gas storage space of the shale sample at this time is obtained; wherein, the specified humidity is determined by the following steps: water vapor adsorption experiments are conducted on parallel samples of the shale sample at different environmental humidities to determine the maximum water content of the parallel samples at different environmental humidities; based on the maximum water content of the parallel samples at different environmental humidities, a fitting method is used to determine the corresponding relationship between the maximum water content and the environmental humidity; based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-bearing conditions.

[0133] In one embodiment, obtaining the volume of recoverable gas storage space of the shale sample includes: obtaining the volume of recoverable gas storage space of the shale sample using a nitrogen adsorption method.

[0134] In one embodiment, before conducting water vapor adsorption experiments on parallel samples of the shale sample under different ambient humidity conditions, the method further includes: crushing the parallel samples so that the particle size of the crushed parallel samples ranges from 20 to 40 meshes.

[0135] In one embodiment, water vapor adsorption experiments are conducted on parallel samples of the shale sample at different ambient humidity, including: the adsorption experiment time is controlled within 24 hours to 48 hours until the parallel samples reach an adsorption equilibrium state.

[0136] In one embodiment, after determining the water content of the shale sample and before obtaining the volume of the total gas storage space of the dried shale sample, the method further includes: crushing the shale sample so that the particle size of the crushed shale sample ranges from 20 to 40 meshes.

[0137] In one embodiment, the closed pore ratio of the shale sample is determined based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, including: determining the water volume of the shale sample based on the water content of the shale sample; taking the difference between the volume of the total gas storage space of the shale sample and the volume of the recoverable gas storage space and the water volume as the closed pore volume of the shale sample; and taking the ratio of the closed pore volume to the volume of the total gas storage space as the closed pore ratio of the shale sample.

[0138] The nitrogen adsorption method refers to the physical adsorption of nitrogen by shale in a liquid nitrogen environment. In this embodiment, the shale is fully adsorbed in the nitrogen environment until the shale reaches an adsorption equilibrium state.

[0139] It should be noted that in this embodiment, the weight mentioned is in g, and the volume mentioned is in cm. 3 , of which 1cm 3 =1ml.

[0140] Storage media may also include program code, data files, data structures, etc., alone or in combination. The storage medium or program code may be specifically designed and understood by those skilled in the art of computer software, or the storage medium may be well known and available to those skilled in the art of computer software. Examples of storage media include: magnetic media, such as hard disks, floppy disks, and magnetic tapes; optical media, such as CDROMs and DVDs; magneto-optical media, such as optical disks; and hardware devices specifically configured to store and execute program code, such as read-only memory (ROM), random access memory (RAM), flash memory; or servers, app stores, etc. Examples of program code include machine code (e.g., code generated by a compiler) and files containing high-level code that can be executed by a computer using an interpreter. The described hardware devices can be configured to function as one or more software modules to perform the operations and methods described above, and vice versa. In addition, the storage medium can be distributed across a networked computer system, allowing computer code or program code to be stored and executed in a decentralized manner.

[0141] During actual oil and gas exploration, bound water accumulates in shale pores, occupying a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores in shale, bound water can occupy the throats of these smaller pores, creating a certain degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. Shale is governed by differences in pore structure and distribution, and the presence of bound water can result in varying degrees of capillary closure.

[0142] In this example, the water content of the shale sample is obtained. Since the density of water is 1g / cm 3, the water content is the volume of water in the shale. The nitrogen adsorption method is used to obtain the volume of the total gas storage space of the dried shale sample. For parallel samples of the shale sample, the corresponding relationship between water content and humidity is determined. Based on this corresponding relationship, the humidity corresponding to the water content of the shale sample is determined. Then, a water vapor adsorption experiment is conducted on the shale sample at this humidity until the shale sample reaches adsorption equilibrium, obtaining a water-containing sample of the shale sample and the volume of the recoverable gas storage space of the water-containing sample. Finally, based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample, the volume of the capillary closed pore space in the shale sample is obtained. The capillary closed pore ratio of the shale sample is further determined and used as the capillary closed pore ratio of the target shale. This provides technical support for the quantitative assessment of the recoverability of shale under actual burial conditions.

[0143] Example 5

[0144] Another aspect of the present invention provides a computer device comprising: a processor and a memory, wherein the memory stores program code, and when the program code is executed by the processor, implements the method for quantitatively characterizing the proportion of closed pores in shale as described above:

[0145] Obtain the original weight and the weight after drying of the shale sample, and determine the water content of the shale sample under water-bearing conditions in the formation based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under water-bearing conditions in the formation; obtain the volume of the total gas storage space of the dried shale sample; obtain the volume of the recoverable gas storage space of the shale sample under water-bearing conditions in the formation; determine the closed pore ratio of the shale sample based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale.

[0146] In one embodiment, obtaining the weight of the shale sample after drying includes: drying the shale sample at a temperature of 105° C. to 120° C. for more than 24 hours, and then obtaining the weight after drying.

[0147] In one embodiment, obtaining the volume of the total gas storage space of the dried shale sample includes: obtaining the volume of the total gas storage space of the dried shale sample using a nitrogen adsorption method.

[0148] In one embodiment, the volume of the recoverable gas storage space of a shale sample under formation water-bearing conditions is determined according to the following steps: the dried shale sample is placed in an environment with a specified humidity, so that the shale sample has the same water content as under formation water-bearing conditions when it is in water vapor adsorption equilibrium, and the volume of the recoverable gas storage space of the shale sample at this time is obtained; wherein, the specified humidity is determined by the following steps: water vapor adsorption experiments are conducted on parallel samples of the shale sample at different environmental humidities to determine the maximum water content of the parallel samples at different environmental humidities; based on the maximum water content of the parallel samples at different environmental humidities, a fitting method is used to determine the corresponding relationship between the maximum water content and the environmental humidity; based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-bearing conditions.

[0149] In one embodiment, obtaining the volume of recoverable gas storage space of the shale sample includes: obtaining the volume of recoverable gas storage space of the shale sample using a nitrogen adsorption method.

[0150] In one embodiment, before conducting water vapor adsorption experiments on parallel samples of the shale sample under different ambient humidity conditions, the method further includes: crushing the parallel samples so that the particle size of the crushed parallel samples ranges from 20 to 40 meshes.

[0151] In one embodiment, water vapor adsorption experiments are conducted on parallel samples of the shale sample at different ambient humidity, including: the adsorption experiment time is controlled within 24 hours to 48 hours until the parallel samples reach an adsorption equilibrium state.

[0152] In one embodiment, after determining the water content of the shale sample and before obtaining the volume of the total gas storage space of the dried shale sample, the method further includes: crushing the shale sample so that the particle size of the crushed shale sample ranges from 20 to 40 meshes.

[0153] In one embodiment, the closed pore ratio of the shale sample is determined based on the volume of the total gas storage space, the volume of the recoverable gas storage space and the water content of the shale sample, including: determining the water volume of the shale sample based on the water content of the shale sample; taking the difference between the volume of the total gas storage space of the shale sample and the volume of the recoverable gas storage space and the water volume as the closed pore volume of the shale sample; and taking the ratio of the closed pore volume to the volume of the total gas storage space as the closed pore ratio of the shale sample.

[0154] The nitrogen adsorption method refers to the physical adsorption of nitrogen by shale in a liquid nitrogen environment. In this embodiment, the shale is fully adsorbed in the nitrogen environment until the shale reaches an adsorption equilibrium state.

[0155] It should be noted that in this embodiment, the weight mentioned is in g, and the volume mentioned is in cm. 3 , of which 1cm 3 =1ml.

[0156] The processor can be an application specific integrated circuit (ASIC), a digital signal processor (DSP), a digital signal processing device (DSPD), a programmable logic device (PLD), a field programmable gate array (FPGA), a controller, a microcontroller, a microprocessor, or other electronic components, and is used to execute the method for quantitatively characterizing the proportion of closed pores in shale as described above.

[0157] The memory can be implemented by any type of volatile or non-volatile memory device or a combination of them, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk or optical disk, etc.

[0158] The processing, functions, methods and / or software described above can be recorded, stored or fixed in one or more computer-readable storage media, and the storage medium includes program code, and the program code will be implemented by a computer so that the processor executes the program code. The storage medium can also include program code, data files, data structures, etc. separately, or include a combination thereof. The storage medium or program code can be specifically designed and understood by those skilled in the art of computer software, or the storage medium or program code can be known and available to those skilled in the art of computer software. Examples of program code include machine code (for example, code generated by a compiler) and files containing high-level code, which can be executed by a computer using an interpreter. The described hardware device can be configured to serve as one or more software modules to perform the operations and methods described above, and vice versa. In addition, the computer-readable storage medium can be distributed in a networked computer system, and the computer-readable code or program code can be stored and executed in a decentralized manner.

[0159] It should be noted that the device may include one or more processors and memory (i.e., computer-readable storage medium), which may be connected via a bus or other means. The memory, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The processor executes the non-volatile software programs, program code, and modules stored in the memory to perform various functional applications and data processing of the device, thereby implementing the method for quantitatively characterizing the proportion of closed pores in shale as described above.

[0160] During actual oil and gas exploration, bound water accumulates in shale pores, occupying a portion of the pore space. Furthermore, due to the presence of micro- and nano-pores in shale, bound water can occupy the throats of these smaller pores, creating a certain degree of capillary closure, similar to "isolated pores." This makes the hydrocarbon gas stored in these pores difficult to effectively recover. Shale is governed by differences in pore structure and distribution, and the presence of bound water can result in varying degrees of capillary closure.

[0161] In this example, the water content of the shale sample is obtained. Since the density of water is 1g / cm 3, the water content is the volume of water in the shale. The nitrogen adsorption method is used to obtain the volume of the total gas storage space of the dried shale sample. For parallel samples of the shale sample, the corresponding relationship between water content and humidity is determined. Based on this corresponding relationship, the humidity corresponding to the water content of the shale sample is determined. Then, a water vapor adsorption experiment is conducted on the shale sample at this humidity until the shale sample reaches adsorption equilibrium, obtaining a water-containing sample of the shale sample and the volume of the recoverable gas storage space of the water-containing sample. Finally, based on the volume of the total gas storage space, the volume of the recoverable gas storage space, and the water content of the shale sample, the volume of the capillary closed pore space in the shale sample is obtained. The capillary closed pore ratio of the shale sample is further determined and used as the capillary closed pore ratio of the target shale. This provides technical support for the quantitative assessment of the recoverability of shale under actual burial conditions.

[0162] In summary, the present application provides a method, device, storage medium and electronic device for quantitatively characterizing the proportion of closed pores in shale. By obtaining the water content or water content of the shale sample, since the density of water is 1g / cm 3 , then the value of water content is the volume of water in shale, and the value of water content is the volume of water per unit mass (per gram) of dry shale; the volume of the total gas storage space of the dried shale sample is obtained by nitrogen adsorption method; for the parallel samples of the shale sample, the corresponding relationship between water content and humidity or the corresponding relationship between water content and humidity is determined; based on the corresponding relationship, the humidity corresponding to the water content of the shale sample or the humidity corresponding to the water content of the shale sample is determined, and then the water vapor adsorption experiment and direct test are carried out on the shale sample at the humidity. Once the shale sample reaches adsorption equilibrium, a water-containing sample is obtained, and the volume of the recoverable gas storage space in the water-containing sample is determined using nitrogen adsorption. Finally, the volume of the capillary-enclosed pore space per unit mass of the shale sample (per gram) is calculated based on the total gas storage space volume, the recoverable gas storage volume, and the water content or moisture content. The capillary-enclosed pore ratio of the shale sample is further determined, and this is used as the capillary-enclosed pore ratio of the target shale. This provides technical support for quantitatively evaluating the recoverability of shale under actual burial conditions.

[0163] The several embodiments provided in this application can all be used to execute the method for quantitatively characterizing the proportion of closed pores in shale as described above. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects of the corresponding methods provided above and will not be repeated here.

[0164] In addition, it should be understood that the methods disclosed in several embodiments provided in the embodiments of the present application may also be implemented in other ways. The method embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions, and operations of the methods and devices according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, a program code segment, or a portion of a program code, and the module, program code segment, or a portion of a program code contains one or more program codes for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the boxes may also occur in an order different from that marked in the drawings, and may actually be executed substantially in parallel, or they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, may be implemented using a dedicated hardware-based system that performs the specified functions or actions, or may be implemented using a combination of dedicated hardware and program code.

[0165] Finally, it should be noted that in the present invention, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements but also other elements not explicitly listed, or also includes elements inherent to such process, method, article, or device. Without further limitation, an element defined by the phrase "comprising a..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element; in the present invention, if there is a description of "first," "second," etc., it is only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features; in the description of the present invention, unless otherwise explicitly defined, terms such as connection, wax seal, and fresh unsealing should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meaning of the terms in the present invention in combination with the specific content of the technical solution. In addition, in the description of the present application, unless otherwise specified, "multiple" and "many" mean at least two.

[0166] Although the embodiments disclosed herein are as described above, the contents described herein are merely embodiments for facilitating understanding of the present invention and are not intended to limit the present invention. Any person skilled in the art may make any modifications and variations in the form and details of the embodiments without departing from the spirit and scope of the present invention. However, the scope of protection of the present invention shall remain subject to the scope defined by the appended claims.

Claims

1. A method for quantitatively characterizing the proportion of closed pores in shale, characterized in that: The following steps are involved: Obtaining the original weight and the weight after drying of the shale sample, and determining the water content per unit mass of the shale sample under formation water-bearing conditions based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under formation water-bearing conditions; Crushing the shale sample so that the particle size of the crushed shale sample is in the range of 20-40 mesh, thereby obtaining a first shale sample; The volume of the total gas storage space per unit mass of the dried first shale sample is obtained using a nitrogen adsorption method; wherein the drying step includes: controlling the drying time of the first shale sample to be greater than 24 hours at a temperature of 105° C. to 120° C.; Obtaining the volume of recoverable gas storage space per unit mass of the shale sample under formation water-bearing conditions; Determining the closed pore ratio of the shale sample based on the volume of the total gas storage space per unit mass, the volume of the recoverable gas storage space per unit mass, and the water content per unit mass, and using the closed pore ratio of the shale sample as the closed pore ratio of the target shale; Wherein, obtaining the volume of recoverable gas storage space per unit mass of the shale sample under formation water-bearing conditions includes: The dried shale sample is placed in an environment with a specified humidity so that the shale sample has the same water content as that under formation water conditions when the shale sample is in water vapor adsorption equilibrium, and the volume of recoverable gas storage space per unit mass of the shale sample at this time is obtained; wherein the specified humidity is determined by the following steps: Conducting water vapor adsorption experiments on parallel samples of the shale sample at different ambient humidity levels to determine the maximum water content of the parallel samples at different ambient humidity levels; Determine the corresponding relationship between the maximum water content and the ambient humidity using a fitting method according to the maximum water content of the parallel samples under different ambient humidity conditions; Based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-containing conditions; Determining the closed pore ratio of the shale sample according to the volume of the total gas storage space per unit mass, the volume of the recoverable gas storage space per unit mass, and the water content per unit mass includes: Determining the water content per unit mass of the shale sample under formation water-bearing conditions based on the water content per unit mass; The difference between the volume of the total gas storage space per unit mass and the volume of the recoverable gas storage space per unit mass and the water volume per unit mass is taken as the closed pore volume per unit mass of the shale sample; The ratio of the closed pore volume per unit mass to the volume of the total gas storage space per unit mass is taken as the closed pore ratio of the shale sample.

2. The method according to claim 1, characterized in that According to the maximum water content of the parallel samples under different ambient humidity, a corresponding relationship between the maximum water content and the ambient humidity is determined by using a fitting method, including: The maximum water content of the parallel samples under different ambient humidity is fitted using the GAB model to determine the corresponding relationship between the maximum water content and the ambient humidity.

3. A device for quantitatively characterizing the proportion of closed pores in shale using the method according to any one of claims 1 to 2, characterized in that: include: a water content determination module, configured to obtain the original weight and the weight after drying of the shale sample, and determine the water content per unit mass of the shale sample under formation water-bearing conditions based on the original weight and the weight after drying, wherein the original weight of the shale sample is the weight of the shale sample under formation water-bearing conditions; a first volume determination module configured to obtain the volume of the total gas storage space per unit mass of the first shale sample after drying using a nitrogen adsorption method; wherein the drying step includes controlling the drying time of the first shale sample to be greater than 24 hours at a temperature of 105° C. to 120° C.; A second volume determination module is used to obtain the volume of recoverable gas storage space per unit mass of the shale sample under formation water-bearing conditions; a calculation module, configured to determine the closed pore ratio of the shale sample based on the volume of the total gas storage space per unit mass, the volume of the recoverable gas storage space per unit mass, and the water content per unit mass, and use the closed pore ratio of the shale sample as the closed pore ratio of the target shale; Wherein, obtaining the volume of recoverable gas storage space per unit mass of the shale sample under formation water-bearing conditions includes: The dried shale sample is placed in an environment with a specified humidity so that the shale sample has the same water content as that under formation water conditions when the shale sample is in water vapor adsorption equilibrium, and the volume of recoverable gas storage space per unit mass of the shale sample at this time is obtained; wherein the specified humidity is determined by the following steps: Conducting water vapor adsorption experiments on parallel samples of the shale sample at different ambient humidity levels to determine the maximum water content of the parallel samples at different ambient humidity levels; Determine the corresponding relationship between the maximum water content and the ambient humidity using a fitting method according to the maximum water content of the parallel samples under different ambient humidity conditions; Based on the corresponding relationship, the specified humidity is determined according to the water content of the shale sample under formation water-containing conditions; Determining the closed pore ratio of the shale sample according to the volume of the total gas storage space per unit mass, the volume of the recoverable gas storage space per unit mass, and the water content per unit mass includes: Determining the water content per unit mass of the shale sample under formation water-bearing conditions based on the water content per unit mass; The difference between the volume of the total gas storage space per unit mass and the volume of the recoverable gas storage space per unit mass and the water volume per unit mass is taken as the closed pore volume per unit mass of the shale sample; The ratio of the closed pore volume per unit mass to the volume of the total gas storage space per unit mass is taken as the closed pore ratio of the shale sample.

4. A storage medium, characterized in that The storage medium stores program codes, and when the program codes are executed by the processor, the method for quantitatively characterizing the proportion of closed pores in shale according to any one of claims 1 to 2 is implemented.

5. A computer device, characterized in that: include: A processor and a memory, wherein the memory stores a program code, and when the program code is executed by the processor, the method for quantitatively characterizing the proportion of closed pores in shale according to any one of claims 1 to 2 is implemented.

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