A method for determining shale organic and inorganic porosity and related methods

Abstract

The present application provides a shale organic porosity and inorganic porosity determination method and related method, the determination method comprises, shale total porosity is obtained by using preset first rule; shale organic matter porosity is obtained by using preset second rule; shale inorganic matter porosity is obtained according to shale total porosity and shale organic matter porosity, according to preset formula. The present application can calculate shale organic matter porosity and inorganic matter porosity, which is helpful to characterize the development degree of shale organic matter pores and inorganic matter pores, and calculate rock reservoir space, fluid saturation and geological reserves.

Description

Technical Field

[0001] This invention belongs to the field of geological exploration technology, and in particular relates to a method for determining the organic and inorganic porosity of shale and related methods. Background Technology

[0002] my country has abundant shale gas resources, with technically recoverable resources of 21.81 × 10⁻⁶. 12 m 3 In 2022, the cumulative proven geological reserves of shale gas in China exceeded 2.7 × 10⁻⁶. 12 m 3 The output reached 240×10 8 m 3 Shale gas has become the main driver of future growth in domestic natural gas reserves and production. As a type of unconventional natural gas resource, shale gas exhibits typical self-generating and self-storing characteristics. Compared to conventional sandstone reservoirs, shale is dense, has extremely low permeability, and primarily develops nanoscale pores.

[0003] The formation and evolution of shale reservoirs are the combined result of inorganic diagenesis and the generation and expulsion of hydrocarbons through the maturation of organic matter. Based on the location of the matrix, shale pores can be divided into two main categories: organic pores and inorganic pores. Inorganic pores are mainly developed in clay minerals, feldspar, and carbonates, and their origins and sources vary depending on factors such as the mineral composition of the shale, diagenesis, cementation, and dissolution. For example, intergranular pores are formed by the flocculation of clay minerals, intergranular pores exist between different types of pyrite, inorganic pores are formed due to volume shrinkage during illite transformation, and dissolution pores are formed by the dissolution of feldspar and other minerals. The formation of organic pores mainly depends on the hydrocarbon generation process during shale maturation, including kerogen pores formed by the generation and expulsion of hydrocarbons from kerogen and bitumen pores formed during the cracking of retained crude oil. The Longmaxi Formation shale in southern my country, controlled by the type and maturity of organic matter, exhibits abundant organic pores. The presence or absence of organic pores has become an important indicator for evaluating shale gas reservoirs and selecting sweet spots. Summary of the Invention

[0004] To enrich porosity testing methods for wider application scenarios, this invention proposes a method for determining the porosity of a multi-component matrix in shale and related methods, including:

[0005] In a first aspect, embodiments of the present invention provide a method for determining the organic and inorganic porosity of shale, comprising:

[0006] The total porosity of shale is obtained using a preset first rule;

[0007] The porosity of shale organic matter is obtained using a pre-defined second rule;

[0008] Based on the total porosity of the shale and the porosity of the organic matter in the shale, the inorganic porosity of the shale is obtained using the following formula:

[0009]

[0010] in, Porosity of inorganic matter in shale; This represents the total porosity of the shale. This refers to the porosity of organic matter in shale.

[0011] In an optional embodiment, obtaining the total porosity of shale using a preset first rule includes:

[0012] The shale sample was placed in a gas porosimeter and a vacuum was drawn to remove the air from the pores of the sample.

[0013] Without applying confining pressure, helium gas at a certain pressure is applied to allow it to enter the pores;

[0014] Set the gas pressure and equilibrium time, wait for the pressure to reach equilibrium, and then obtain the total porosity of the shale.

[0015] In an optional embodiment, obtaining the porosity of shale organic matter using a preset second rule includes:

[0016] The porosity of organic matter pores relative to the total area is obtained using a pre-defined third rule.

[0017] The face rate conversion coefficient is obtained using the preset fourth rule;

[0018] Based on the porosity of organic matter pores relative to the total area and the porosity conversion coefficient, the porosity of shale organic matter is obtained using the following formula:

[0019]

[0020] in, Porosity of organic matter in shale; C sv This is the face rate conversion factor; The organic matter porosity is the percentage of the total surface area occupied by organic matter pores.

[0021] In an optional embodiment, obtaining the organic matter porosity (the percentage of organic matter pores in the total area) using a preset third rule includes:

[0022] Scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples;

[0023] Using preset image processing software, all organic matter regions in the first scanning electron microscope image of the shale sample are extracted to obtain the total area fraction of organic matter on the surface of the shale sample.

[0024] The average porosity of organic matter pores was obtained from the first scanning electron microscope image of the shale sample according to a preset fifth rule;

[0025] Based on the total area fraction of organic matter on the surface of the shale sample and the average porosity of the organic matter pores, the porosity of organic matter pores in the total area is obtained by the following formula:

[0026]

[0027] in, The porosity of organic matter is the ratio of organic matter pores to the total area. The average porosity of the organic matter pores; S ot This represents the total area fraction of all organic matter on the surface of the shale sample.

[0028] In an optional embodiment, the step of performing an electron microscopy (SEM) experiment on the shale sample to obtain a first SEM image of the shale sample includes:

[0029] Select shale samples from the target stratum and polish them according to a preset area to obtain polished shale samples;

[0030] The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample;

[0031] The treated shale sample was placed in a field emission scanning electron microscope for surface imaging.

[0032] A region of a predetermined area is selected for the processed shale sample;

[0033] Set the scanning electron microscope to continuous imaging mode to acquire a preset number of continuous scanning electron microscope images of the preset area.

[0034] The preset number of consecutive scanning electron microscope (SEM) images are stitched together to generate the first SEM image.

[0035] In an optional embodiment, obtaining the average porosity of organic matter pores from the first scanning electron microscope image of the shale sample according to a preset fifth rule includes:

[0036] In the first scanning electron microscope image, a preset number of shale organic matter development locations are selected, and each selected shale organic matter development location is imaged with an electron microscope at a preset magnification and a preset area to generate a corresponding second scanning electron microscope image.

[0037] The organic matter pores in each second scanning electron microscope image are identified and processed to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0038] Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0039]

[0040] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi Area of ​​each organic matter region;

[0041] Based on the porosity of each organic matter pore, the average porosity of the organic matter pores is obtained using the following formula:

[0042]

[0043] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of selected shale organic matter development locations.

[0044] In an optional embodiment, the identification and processing of organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region includes:

[0045] The organic matter pores in each second scanning electron microscope image were identified using preset image processing software to obtain each group of shale organic matter pores;

[0046] Each group of shale organic matter pores was color-marked using preset image processing software to obtain each group of color-marked shale organic matter pores;

[0047] The color-marked shale organic matter pores in each group are processed using preset software to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0048] In an optional embodiment, obtaining the face rate conversion coefficient using a preset fourth rule includes:

[0049] Using preset image processing software, all organic matter regions in the first scanning electron microscope image of the shale sample are extracted to obtain the total area fraction of organic matter on the surface of the shale sample.

[0050] The volume fraction of organic matter in the sample is obtained using the pre-defined sixth rule;

[0051] Based on the total area fraction of organic matter on the surface of the shale sample and the volume fraction of organic matter in the sample, the porosity conversion factor is obtained according to the following formula:

[0052]

[0053] in, C sv This is the face rate conversion factor; V org This represents the volume fraction of organic matter in the sample. S ot The total area fraction of organic matter on the surface of shale samples; V org This represents the volume fraction of organic matter in the sample.

[0054] In an optional embodiment, obtaining the volume fraction of organic matter in the sample using a preset sixth rule includes:

[0055] Based on the organic matter content, density, and organic matter density of the shale sample, the volume fraction of organic matter in the sample is obtained using the following formula:

[0056]

[0057] in, V org This represents the volume fraction of organic matter in the sample. TOC The organic matter content of the shale sample; ρ s Density of shale sample, g / cm³ 3 ;ρ org Density of shale organic matter, g / cm³ 3 .

[0058] In an optional embodiment, obtaining the porosity of shale organic matter using a preset second rule includes:

[0059] Based on the porosity of organic matter pores relative to the total area and the porosity conversion coefficient, the porosity of shale organic matter is obtained using the following formula:

[0060]

[0061] in, Porosity of organic matter in shale; C sv This is the face rate conversion factor; The organic matter porosity is the percentage of the total surface area occupied by organic matter pores.

[0062] Secondly, embodiments of the present invention provide a method for evaluating oil and gas reservoirs, including the method for determining the inorganic and organic porosity of shale as described above.

[0063] Thirdly, embodiments of the present invention provide a method for determining the porosity of organic matter, which is the ratio of organic matter pores to the total area, comprising:

[0064] Scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples;

[0065] Using preset image processing software, all organic matter regions in the first scanning electron microscope image of the shale sample are extracted to obtain the total area fraction of organic matter on the surface of the shale sample.

[0066] The average porosity of organic matter pores was obtained from the first scanning electron microscope image of the shale sample according to a preset fifth rule;

[0067] Based on the total area fraction of organic matter on the surface of the shale sample and the average porosity of the organic matter pores, the porosity of organic matter pores in the total area is obtained by the following formula:

[0068]

[0069] in, The porosity of organic matter is the ratio of organic matter pores to the total area. The average porosity of the organic matter pores; S ot This represents the total area fraction of all organic matter on the surface of the shale sample.

[0070] In an optional embodiment, the step of performing an electron microscopy (SEM) experiment on the shale sample to obtain a first SEM image of the shale sample includes:

[0071] Select shale samples from the target stratum and polish them according to a preset area to obtain polished shale samples;

[0072] The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample;

[0073] The treated shale sample was placed in a field emission scanning electron microscope for surface imaging.

[0074] A region of a predetermined area is selected for the processed shale sample;

[0075] Set the scanning electron microscope to continuous imaging mode to acquire a preset number of continuous scanning electron microscope images of the preset area.

[0076] The preset number of consecutive scanning electron microscope (SEM) images are stitched together to generate the first SEM image.

[0077] In an optional embodiment, obtaining the average porosity of organic matter pores from the first scanning electron microscope image of the shale sample according to a preset fifth rule includes:

[0078] In the first scanning electron microscope image, a preset number of shale organic matter development locations are selected, and each selected shale organic matter development location is imaged with an electron microscope at a preset magnification and a preset area to generate a corresponding second scanning electron microscope image.

[0079] The organic matter pores in each second scanning electron microscope image are identified and processed to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0080] Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0081]

[0082] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi Area of ​​each organic matter region;

[0083] Based on the porosity of each organic matter pore, the average porosity of the organic matter pores is obtained using the following formula:

[0084]

[0085] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of shale organic matter development locations selected from the preset range.

[0086] In an optional embodiment, the identification and processing of organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region includes:

[0087] The organic matter pores in each second scanning electron microscope image were identified using preset image processing software to obtain each group of shale organic matter pores;

[0088] Each group of shale organic matter pores was color-marked using preset image processing software to obtain each group of color-marked shale organic matter pores;

[0089] The color-marked shale organic matter pores in each group are processed using preset software to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0090] Fourthly, embodiments of the present invention provide a method for generating scanning electron microscope images of shale samples, comprising:

[0091] Select shale samples from the target stratum and polish them according to a preset area to obtain polished shale samples;

[0092] The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample;

[0093] The treated shale sample was placed in a field emission scanning electron microscope for surface imaging.

[0094] A region of a predetermined area is selected for the processed shale sample;

[0095] Set the scanning electron microscope to continuous imaging mode to acquire a preset number of continuous scanning electron microscope images of the preset area.

[0096] The predetermined number of consecutive scanning electron microscope (SEM) images are stitched together to generate a scanning electron microscope image of the shale sample.

[0097] Fifthly, embodiments of the present invention provide a method for determining the average porosity of organic matter pores, comprising:

[0098] Scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples;

[0099] In the first scanning electron microscope image, a preset number of shale organic matter development locations are selected, and each selected shale organic matter development location is imaged with an electron microscope at a preset magnification and a preset area to generate a corresponding second scanning electron microscope image.

[0100] The organic matter pores in each second scanning electron microscope image are identified and processed to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0101] Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0102]

[0103] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi Area of ​​each organic matter region;

[0104] Based on the porosity of each organic matter pore, the average porosity of the organic matter pores is obtained using the following formula:

[0105]

[0106] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of selected shale organic matter development locations.

[0107] In an optional embodiment, the identification and processing of organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region includes:

[0108] The organic matter pores in each second scanning electron microscope image were identified using preset image processing software to obtain each group of shale organic matter pores;

[0109] Each group of shale organic matter pores was color-marked using preset image processing software to obtain each group of color-marked shale organic matter pores;

[0110] The color-marked shale organic matter pores in each group are processed using preset software to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0111] In an optional embodiment, the step of performing an electron microscopy (SEM) experiment on the shale sample to obtain a first SEM image of the shale sample includes:

[0112] Select shale samples from the target stratum and polish them according to a preset area to obtain polished shale samples;

[0113] The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample;

[0114] The treated shale sample was placed in a field emission scanning electron microscope for surface imaging.

[0115] Select a region of preset area, set continuous imaging, and acquire a preset number of continuous scanning electron microscope images;

[0116] The first scanning electron microscope (SEM) image is generated by stitching together a preset number of consecutive SEM images.

[0117] Based on the above technical solution, the beneficial effects of the present invention compared with the prior art are as follows:

[0118] This invention establishes an interpretation model for organic and inorganic porosity in shale, clarifying the relationship between total shale porosity, organic porosity, and inorganic porosity. The method for determining organic and inorganic porosity in shale proposed in this invention can measure multiple shale samples from the same stratum. Using parameters such as the organic porosity of the total area occupied by organic porosity, the porosity conversion coefficient, the total area fraction of organic matter, and the volume fraction of organic matter in the sample, the organic porosity of shale can be calculated. Subtracting the organic porosity from the total porosity yields the inorganic porosity of shale, which helps characterize the development degree of organic and inorganic pores in shale, and facilitates calculations of rock reservoir space, fluid saturation, and geological reserves. Attached Figure Description

[0119] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0120] Figure 1 This is a flowchart illustrating the method for determining the organic and inorganic porosity of shale according to an embodiment of the present invention.

[0121] Figure 2 A schematic diagram of the process for obtaining the total porosity of shale using a first rule, provided in an embodiment of the present invention;

[0122] Figure 3 A schematic diagram of the process for obtaining the porosity of shale organic matter using a preset second rule, provided in an embodiment of the present invention;

[0123] Figure 4 A schematic diagram of the process for obtaining the organic matter porosity as a percentage of the total area using a preset third rule, provided for an embodiment of the present invention;

[0124] Figure 5 A schematic diagram of the process for obtaining the first scanning electron microscope image of a shale sample by conducting an electron microscopy scanning experiment according to an embodiment of the present invention;

[0125] Figure 6 High-resolution large-area scanning electron microscope images provided for embodiments of the present invention;

[0126] Figure 7 This is a schematic diagram of the process for obtaining the average porosity of organic matter pores from the first scanning electron microscope image of a shale sample according to a preset fifth rule, as provided in an embodiment of the present invention.

[0127] Figure 8This is a schematic diagram illustrating the process of identifying and processing organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region, as provided in an embodiment of the present invention.

[0128] Figure 9 A schematic diagram of organic matter pores marked in gray, provided for an embodiment of the present invention;

[0129] Figure 10 This is a schematic diagram illustrating the process of obtaining face rate conversion coefficients using a preset fourth rule, as provided in an embodiment of the present invention. Detailed Implementation

[0130] Porosity is a parameter for evaluating the reservoir properties of shale. Currently, various methods have been established to test the total porosity of shale, but they cannot accurately determine the organic and inorganic porosity in shale. The current methods for evaluating the organic and inorganic porosity of shale mainly have the following shortcomings: (1) Although high-resolution scanning electron microscopy can quantitatively analyze the organic porosity of samples, it is mainly based on small-area scanning electron microscopy images and cannot reflect the overall porosity development of shale. (2) Based on the difference in wettability of organic and inorganic minerals in shale, organic and inorganic pores are distinguished by nuclear magnetic resonance saturation water and oil experiments. However, the theoretical basis of this method is based on the difference in wettability of shale matrix. Shale mineral composition is complex and organic matter types are diverse. Using this method cannot accurately measure the degree of development of organic pores in shale. The inability to clearly distinguish between organic and inorganic pores in shale is not conducive to the calculation of rock storage space, fluid saturation and geological reserves. Therefore, the inventors made this invention after further research and development.

[0131] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0132] Example 1

[0133] This invention provides a method for determining the organic and inorganic porosity of shale, combined with... Figure 1 As shown, steps S110 to S130 are included:

[0134] Step S110: Obtain the total porosity of shale using a preset first rule.

[0135] In one embodiment, the total porosity of the shale is obtained using a first rule, such as... Figure 2 As shown, steps S111 to S123 are included:

[0136] Step S111: Place the shale sample into a gas porosimeter and evacuate to remove air from the pores of the sample.

[0137] Specifically, after placing the shale sample into the gas porosimeter, it is necessary to evacuate the shale sample to remove the air. Under normal circumstances, the evacuation time is set to 2 hours to ensure that the air in the shale sample is completely removed.

[0138] Step S112: Without applying confining pressure, apply helium gas at a certain pressure to allow it to enter the pores.

[0139] Specifically, the gas porosimeter can test samples under both confining and non-confining pressure conditions. Under confining pressure, the sample is affected by external pressure, and the pores are compressed. The porosity obtained by measurement is not the total porosity. However, the porosity obtained under non-confining pressure is the total porosity value. In this invention, the total porosity value is required. Therefore, under non-confining pressure, helium gas at a certain pressure needs to be applied to allow it to enter the pores of the shale sample.

[0140] Step S113: Set the gas pressure and equilibrium time, and after the pressure is balanced, obtain the total porosity of the shale.

[0141] Specifically, while waiting for the pressure in the pores of the shale sample to reach equilibrium, equilibrium conditions need to be set. Generally, the equilibrium condition is set to a pressure change of less than 1 psi within 10 minutes. After setting the equilibrium condition, the porosity meter will automatically determine whether the pressure in the shale sample has reached equilibrium.

[0142] The porosity analyzer system software can be used to analyze the helium gas under a set initial gas pressure by making it expand isothermally into the core chamber according to Boyle's law. The gas continuously diffuses into the pores inside the core. The pore volume can be calculated based on the pressure change characteristics, the size of the core chamber, and the gas state equation.

[0143] In one specific embodiment, the gas pressure is set to 600 psi and the equilibrium time is 1 hour. After the pressure reaches equilibrium, the total porosity is calculated using Boyle's law. =4.24%.

[0144] Step S120: Obtain the porosity of shale organic matter using a preset second rule.

[0145] In one embodiment, the porosity of shale organic matter is obtained using a preset second rule, such as... Figure 3 As shown, step S120 includes steps S121 to S123:

[0146] Step S121: Obtain the organic matter porosity as the percentage of the total area of ​​organic matter pores using a preset third rule.

[0147] Specifically, the organic matter porosity is obtained by using a pre-defined third rule, which represents the total area of ​​the shale sample. Figure 4As shown, step S121 includes steps S1211 to S1213.

[0148] Step S1211: Perform an electron microscopy (SEM) experiment on the shale sample to obtain the first SEM image of the shale sample.

[0149] Specifically, scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples, such as... Figure 5 As shown, step S1211 includes steps S1211' to S1216':

[0150] Step S1211': Select the shale sample from the target layer and polish it according to the preset area to obtain the polished shale sample.

[0151] In one embodiment, a shale sample with well-developed organic porosity from the target formation was selected. The sample came from the Longmaxi Formation in the southern Sichuan Basin. A combination of manual polishing and argon ion polishing was used to polish the sample surface over a large area, reaching 1 mm × 1 mm.

[0152] Step S1212': The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample.

[0153] In one embodiment, the surface of the shale sample is subjected to high-vacuum carbon spraying or gold plating to enhance the conductivity of the sample.

[0154] Step S1213': Place the processed shale sample into a field emission scanning electron microscope for surface imaging.

[0155] In one embodiment, the shale sample is placed in a field emission scanning electron microscope (SEM) with a maximum resolution of 1 nm. After locating the polished area on the sample surface, the sample surface is imaged using backscatter mode with a magnification of 2500x, an image width of 110 μm, and a resolution of 27 nm.

[0156] Step S1214': Select a region of a preset area for the processed shale sample.

[0157] Step S1215': Set the scanning electron microscope to continuous imaging mode and acquire a preset number of continuous scanning electron microscope images of the preset area.

[0158] Step S1216': The preset number of consecutive scanning electron microscope (SEM) images are stitched together to generate a first SEM image.

[0159] In one embodiment, a shale sample with a region of 330 μm × 330 μm was selected for imaging, and nine consecutive scanning electron microscope (SEM) images were obtained. These SEM images were then stitched together to obtain a large-area SEM image with relatively high resolution, such as... Figure 6As shown.

[0160] Step S1212: Use preset image processing software to extract all organic matter regions in the first scanning electron microscope image of the shale sample to obtain the total area fraction of organic matter on the surface of the shale sample.

[0161] Specifically, the preset image processing software can be Photoshop, ImageJ, etc., and the total area fraction of organic matter on the surface of the shale sample can be obtained through image processing software. S ot It is 16.1%.

[0162] Step S1213: Obtain the average porosity of organic matter pores from the first scanning electron microscope image of the shale sample according to the preset fifth rule.

[0163] Specifically, the average porosity of organic matter pores is obtained from the first scanning electron microscope image of the shale sample according to a preset fifth rule, such as... Figure 7 As shown, step S1213 includes steps S12131' to S12114':

[0164] Step S12131': Select a preset number of shale organic matter development locations in the first scanning electron microscope image, and perform electron microscopy imaging on each selected shale organic matter development location at a preset magnification and with a preset area to generate a corresponding second scanning electron microscope image.

[0165] Step S12132': Identify and process the organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0166] Specifically, such as Figure 8 As shown, step S12132' includes steps S12141 to S12143:

[0167] Step S12141: Use preset image processing software to identify the organic matter pores in each second scanning electron microscope image to obtain each group of shale organic matter pores.

[0168] Step S12142: Use preset image processing software to color-mark each group of shale organic matter pores to obtain each group of color-marked shale organic matter pores.

[0169] Step S12143: Use preset software to process the pores of each group of color-marked shale organic matter to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0170] Step S12133': Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0171]

[0172] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi The area of ​​each organic matter region.

[0173] Step S12134': Based on the porosity of each organic matter pore relative to the total porosity of the organic matter, the average porosity of the organic matter pores is obtained using the following formula:

[0174]

[0175] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of selected shale organic matter development locations.

[0176] In one specific embodiment, organic matter development sites are selected from large-area scanning electron microscope (SEM) images of shale samples. More than 20 sites are selected. During imaging of these selected sites, the SEM magnification is set to 10,000x, the image width to 27.5 μm, and the resolution to 6.75 nm. Typically, 144 organic matter development sites are selected, as shown below. Figure 9 As shown on the left, a scanning electron microscope (SEM) image of one of the organic matter development locations was obtained. Image processing software, including Photoshop and ImageJ, was used to identify the internal pores of the organic matter in the SEM image based on grayscale differences. The organic matter pores were marked in gray. The marked organic matter is shown below. Figure 9 As shown on the right.

[0177] The electron microscopy images of each organic matter development location were processed using image processing software, resulting in one organic matter area of ​​9.8 × 10⁻⁶. 7 nm 2 The organic pore area within the organic matter is 1.39 × 10⁻⁶. 7 nm 2 The porosity of a single organic matter particle was calculated. = (1.39 × 10 7 ) / (9.8×10 7=14.15%.

[0178] The organic matter surface rates at the selected 144 organic matter development sites were summed:

[0179]

[0180] The cumulative value of the organic matter surface area ratio is processed to obtain the average surface area ratio of organic matter. =2227.68 / 144=15.47%.

[0181] Step S1214: Based on the total area fraction of organic matter on the surface of the shale sample and the average porosity of the organic matter pores, the porosity of organic matter pores is obtained using the following formula:

[0182]

[0183] in, The porosity of organic matter is the ratio of organic matter pores to the total area. The average porosity of the organic matter pores; S ot This represents the total area fraction of all organic matter on the surface of the shale sample.

[0184] In one specific embodiment, since the porosity can only reflect the development of organic matter pores on the two-dimensional surface of the sample, but cannot reflect the pore development of the sample in three dimensions, it is necessary to establish a porosity conversion coefficient to convert the obtained organic matter porosity into organic matter porosity.

[0185] By extracting all organic matter regions from large-area electron microscopy images of shale samples, the total area fraction of all organic matter on the sample surface can be obtained. S ot The organic matter surface rate was 16.1%. =15.47%×16.1%=2.49%.

[0186] Step S122: Obtain the face rate conversion coefficient using the preset fourth rule.

[0187] Specifically, the face rate conversion coefficient is obtained using the preset fourth rule, such as... Figure 10 As shown, steps S1221 to S1223 are included:

[0188] Step S1221: Use preset image processing software to extract all organic matter regions in the first scanning electron microscope image of the shale sample to obtain the total area fraction of organic matter on the surface of the shale sample.

[0189] Step S1222: Obtain the volume fraction of organic matter in the sample using the preset sixth rule.

[0190] Specifically, the volume fraction of organic matter in the sample is obtained using the preset sixth rule, including:

[0191] Based on the organic matter content, density, and organic matter density of the shale sample, the volume fraction of organic matter in the sample is obtained using the following formula:

[0192]

[0193] in, V org This represents the volume fraction of organic matter in the sample. TOC This refers to the organic matter content of the shale sample. ρ s Density of shale sample, g / cm³ 3 ; ρ org Density of shale organic matter, g / cm³ 3 .

[0194] Specifically, after burning the shale sample, a carbon-sulfur analyzer was used to determine that the total organic matter (TOC) content of the shale sample was 5%, and the density of the shale sample was determined to be 2.6 g / cm³ using a shale density test method. 3 The organic matter density of the shale is 1.3 g / cm³. 3 The volume fraction of organic matter in the sample was obtained. V org =5%×2.6 / 1.3=10%.

[0195] Step S1223: Based on the total area fraction of organic matter on the surface of the shale sample and the volume fraction of organic matter in the sample, the porosity conversion coefficient is obtained according to the following formula:

[0196]

[0197] in, C sv This is the face rate conversion factor; V org This represents the volume fraction of organic matter in the sample. S ot The total area fraction of organic matter on the surface of shale samples; V org This represents the volume fraction of organic matter in the sample.

[0198] Specifically, the porosity conversion factor is calculated by using the volume fraction of organic matter in the sample and the total area fraction of organic matter on the shale sample surface. C sv =10% / 16.1%=0.62.

[0199] Step S123: Based on the porosity of organic matter pores relative to the total area and the porosity conversion coefficient, the porosity of shale organic matter is obtained according to the following formula:

[0200]

[0201] in, Porosity of organic matter in shale; C sv This is the face rate conversion factor; The organic matter porosity is the percentage of the total surface area occupied by organic matter pores.

[0202] Specifically, the porosity of organic matter can be obtained by using the face conversion coefficient and the porosity of shale organic matter. =2.49%×0.62=1.54%.

[0203] Step S130: Based on the total porosity of the shale and the porosity of the organic matter in the shale, the inorganic porosity of the shale is obtained according to the following formula:

[0204]

[0205] in, Porosity of inorganic matter in shale; This represents the total porosity of the shale. This refers to the porosity of organic matter in shale.

[0206] Specifically, using the total porosity and organic matter porosity of shale obtained in the above steps, the inorganic matter porosity of shale can be obtained. =4.24% - 1.54% = 2.70%.

[0207] Using the methods described above for determining the organic and inorganic porosity of shale layers, the rock storage space, fluid saturation, and geological reserves can be determined.

[0208] This invention establishes an interpretation model for organic and inorganic porosity in shale, clarifying the relationship between total shale porosity, organic porosity, and inorganic porosity. The method for determining organic and inorganic porosity in shale proposed in this invention can measure multiple shale samples from the same stratum. Using parameters such as the organic porosity of the total area occupied by organic porosity, the porosity conversion coefficient, the total area fraction of organic matter, and the volume fraction of organic matter in the sample, the organic porosity of shale can be calculated. Subtracting the organic porosity from the total porosity yields the inorganic porosity of shale, which helps characterize the development degree of organic and inorganic pores in shale, and facilitates calculations of rock reservoir space, fluid saturation, and geological reserves.

[0209] Example 2

[0210] This invention provides a method for determining the porosity of organic matter, which is the ratio of organic matter pores to the total area, including steps S210 to S240:

[0211] Step S210: Perform an electron microscopy (SEM) experiment on the shale sample to obtain the first SEM image of the shale sample.

[0212] Specifically, scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples, such as... Figure 5 As shown, steps S211 to S216 are included:

[0213] Step S211: Select the shale sample from the target layer and polish it according to the preset area to obtain the polished shale sample.

[0214] In one embodiment, a shale sample with well-developed organic porosity from the target formation was selected. The sample came from the Longmaxi Formation in the southern Sichuan Basin. A combination of manual polishing and argon ion polishing was used to polish the sample surface over a large area, reaching 1 mm × 1 mm.

[0215] Step S212: The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample.

[0216] In one embodiment, the surface of the shale sample is subjected to high-vacuum carbon spraying or gold plating to enhance the conductivity of the sample.

[0217] Step S213: Place the processed shale sample into a field emission scanning electron microscope for surface imaging.

[0218] In one embodiment, the shale sample is placed in a field emission scanning electron microscope (SEM) with a maximum resolution of 1 nm. After locating the polished area on the sample surface, the sample surface is imaged using backscatter mode with a magnification of 2500x, an image width of 110 μm, and a resolution of 27 nm.

[0219] Step S214: Select a region of a preset area for the processed shale sample.

[0220] Step S215: Set the scanning electron microscope to continuous imaging mode and acquire a preset number of continuous scanning electron microscope images of the preset area.

[0221] Step S216: The preset number of consecutive scanning electron microscope (SEM) images are stitched together to generate a first SEM image.

[0222] In one embodiment, a shale sample with a region of 330 μm × 330 μm was selected for imaging, and nine consecutive scanning electron microscope (SEM) images were obtained. These SEM images were then stitched together to obtain a large-area SEM image with relatively high resolution, such as... Figure 6 As shown.

[0223] Step S220: Use preset image processing software to extract all organic matter regions in the first scanning electron microscope image of the shale sample to obtain the total area fraction of organic matter on the surface of the shale sample.

[0224] Specifically, the preset image processing software can be Photoshop, ImageJ, etc., and the total area fraction of organic matter on the surface of the shale sample can be obtained through image processing software. S ot It is 16.1%.

[0225] Step S230: Obtain the average porosity of organic matter pores from the first scanning electron microscope image of the shale sample according to a preset fifth rule.

[0226] Specifically, the average porosity of organic matter pores is obtained from the first scanning electron microscope image of the shale sample according to a preset fifth rule. Step S230 includes steps S231 to S234:

[0227] Step S231: Select a preset number of shale organic matter development locations in the first scanning electron microscope image, and perform electron microscopy imaging on each selected shale organic matter development location with a preset magnification and preset area to generate a corresponding second scanning electron microscope image.

[0228] Step S232: Identify and process the organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0229] Specifically, step S232 includes steps S2321 to S2323:

[0230] Step S2321: Use preset image processing software to identify the organic matter pores in each second scanning electron microscope image to obtain each group of shale organic matter pores.

[0231] Step S2322: Use preset image processing software to color-mark each group of shale organic matter pores to obtain each group of color-marked shale organic matter pores.

[0232] Step S2323: Use preset software to process the pores of each group of colored shale organic matter to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0233] Step S235: Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0234]

[0235] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi The area of ​​each organic matter region.

[0236] Step S236: Based on the porosity of each organic matter pore, the average porosity of the organic matter pores is obtained using the following formula:

[0237]

[0238] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of selected shale organic matter development locations.

[0239] In one specific embodiment, organic matter development locations are selected from large-area scanning electron microscope (SEM) images of shale samples. More than 20 locations are selected, typically 144 locations. High-resolution SEM images of these locations are obtained. During the imaging process of the selected organic matter development locations, the magnification is set to 10,000x, the image width is 27.5 μm, and the resolution is 6.75 nm.

[0240] The electron microscopy images of each organic matter development location were processed using image processing software, resulting in one organic matter area of ​​9.8 × 10⁻⁶. 7 nm 2 The organic pore area within the organic matter is 1.39 × 10⁻⁶. 7 nm 2 The porosity of a single organic matter particle was calculated. = (1.39 × 10 7 ) / (9.8×10 7 =14.15%.

[0241] The organic matter surface rates at the selected 144 organic matter development sites were summed:

[0242]

[0243] The cumulative value of the organic matter surface area ratio is processed to obtain the average surface area ratio of organic matter. =2227.68 / 144=15.47%.

[0244] Step S240: Based on the total area fraction of organic matter on the surface of the shale sample and the average porosity of the organic matter pores, the porosity of organic matter pores is obtained using the following formula:

[0245]

[0246] in, The porosity of organic matter is the ratio of organic matter pores to the total area. The average porosity of the organic matter pores; S ot This represents the total area fraction of all organic matter on the surface of the shale sample.

[0247] Specifically, since the porosity can only reflect the development of organic matter pores on the two-dimensional surface of the sample, and cannot reflect the pore development of the sample in three dimensions, it is necessary to establish a porosity conversion coefficient to convert the obtained organic matter porosity into organic matter porosity.

[0248] By extracting all organic matter regions from large-area electron microscopy images of shale samples, the total area fraction of all organic matter on the sample surface can be obtained. S ot The organic matter porosity was 16.1%, representing the organic matter porosity of the total area. =15.47%×16.1%=2.49%.

[0249] The porosity of organic matter, representing the total surface area of ​​organic matter pores, can characterize the periphery of shale pore structure and reflect the thermal evolution of shale organic matter. This porosity is correlated with total organic carbon (TOC) and can reflect temperature and pressure changes during shale hydrocarbon generation. Furthermore, the established method for producing scanning electron microscopy (SEM) images of shale samples can obtain large-area SEM images, which is beneficial for reflecting the overall porosity development of shale.

[0250] For the figures in the above embodiments, please refer to the accompanying drawings in Embodiment 1.

[0251] Example 3

[0252] This invention provides a method for generating scanning electron microscope images of shale samples, such as... Figure 5 As shown, steps S310 to S360 are included:

[0253] Step S310: Select a shale sample from the target layer and polish it according to a preset area to obtain a polished shale sample.

[0254] In one embodiment, a shale sample with well-developed organic porosity from the target formation was selected. The sample came from the Longmaxi Formation in the southern Sichuan Basin. A combination of manual polishing and argon ion polishing was used to polish the sample surface over a large area, reaching 1 mm × 1 mm.

[0255] Step S320: The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample.

[0256] In one embodiment, the surface of the shale sample is subjected to high-vacuum carbon spraying or gold plating to enhance the conductivity of the sample.

[0257] Step S330: Place the processed shale sample into a field emission scanning electron microscope for surface imaging.

[0258] In one embodiment, the shale sample is placed in a field emission scanning electron microscope (SEM) with a maximum resolution of 1 nm. After locating the polished area on the sample surface, the sample surface is imaged using backscatter mode with a magnification of 2500x, an image width of 110 μm, and a resolution of 27 nm.

[0259] Step S340: Select a region of a preset area for the processed shale sample.

[0260] Step S350: Set the scanning electron microscope to continuous imaging mode and acquire a preset number of continuous scanning electron microscope images of the preset area.

[0261] Step S360: The preset number of consecutive scanning electron microscope (SEM) images are stitched together to generate a scanning electron microscope (SEM) image.

[0262] In one embodiment, a shale sample with a region of 330 μm × 330 μm was selected for imaging, and nine consecutive scanning electron microscope (SEM) images were obtained. These SEM images were then stitched together to obtain a large-area SEM image with relatively high resolution, such as... Figure 6 As shown.

[0263] The established method for producing scanning electron microscope (SEM) images of shale samples can obtain large-area SEM images of shale samples, which is beneficial for reflecting the overall porosity development of shale.

[0264] Example 4

[0265] The present invention provides a method for determining the average porosity of organic matter pores, comprising steps S410 to S470:

[0266] Step S410: Perform an electron microscopy (SEM) experiment on the shale sample to obtain the first SEM image of the shale sample.

[0267] Specifically, scanning electron microscopy (SEM) experiments were conducted on shale samples to obtain the first SEM image of the shale samples, such as... Figure 5 As shown, step S410 includes steps S411 to S416:

[0268] Step S411: Select a shale sample from the target layer and polish it according to the preset area to obtain a polished shale sample.

[0269] In one embodiment, a shale sample with well-developed organic porosity from the target formation was selected. The sample came from the Longmaxi Formation in the southern Sichuan Basin. A combination of manual polishing and argon ion polishing was used to polish the sample surface over a large area, reaching 1 mm × 1 mm.

[0270] Step S412: The surface of the polished shale sample is processed according to a preset process to obtain a processed shale sample.

[0271] In one embodiment, the surface of the shale sample is subjected to high-vacuum carbon spraying or gold plating to enhance the conductivity of the sample.

[0272] Step S413: Place the processed shale sample into a field emission scanning electron microscope for surface imaging.

[0273] In one embodiment, the shale sample is placed in a field emission scanning electron microscope (SEM) with a maximum resolution of 1 nm. After locating the polished area on the sample surface, the sample surface is imaged using backscatter mode with a magnification of 2500x, an image width of 110 μm, and a resolution of 27 nm.

[0274] Step S414: Select a region of a preset area for the processed shale sample.

[0275] Step S415: Set the scanning electron microscope to continuous imaging mode and acquire a preset number of continuous scanning electron microscope images of the preset area.

[0276] Step S416: Stitch together the preset number of consecutive scanning electron microscope (SEM) images to generate a first SEM image.

[0277] In one embodiment, a shale sample with a region of 330 μm × 330 μm was selected for imaging, and nine consecutive scanning electron microscope (SEM) images were obtained. These SEM images were then stitched together to obtain a large-area SEM image with relatively high resolution, such as... Figure 6 As shown.

[0278] Step S420: Select a preset number of shale organic matter development locations in the first scanning electron microscope image, and perform electron microscopy imaging on each selected shale organic matter development location at a preset magnification and with a preset area to generate a corresponding second scanning electron microscope image.

[0279] Step S430: Identify and process the organic matter pores in each second scanning electron microscope image to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0280] Specifically, step S430 includes steps S4301 to S4303:

[0281] Step S4301: Use preset image processing software to identify the organic matter pores in each second scanning electron microscope image to obtain each group of shale organic matter pores.

[0282] Step S4302: Use preset image processing software to color-mark each group of shale organic matter pores to obtain each group of color-marked shale organic matter pores.

[0283] Step S4303: Use preset software to process each group of color-marked shale organic matter pores to obtain the area of ​​each organic matter pore and the area of ​​each organic matter region.

[0284] Step S440: Based on the pore area of ​​each organic matter and the area of ​​each organic matter region, the porosity of each organic matter pore is obtained according to the following formula:

[0285]

[0286] in, The porosity of each organic matter pore in the organic matter; S opi The pore area of ​​each organic matter; S orgi The area of ​​each organic matter region.

[0287] Step S450: Based on the porosity of each organic matter pore relative to the total porosity of the organic matter, the average porosity of the organic matter pores is obtained using the following formula:

[0288]

[0289] in, The average porosity of the organic matter pores; The porosity of each organic matter pore is the porosity of the organic matter; n is the number of selected shale organic matter development locations.

[0290] In one specific embodiment, organic matter development locations are selected from large-area scanning electron microscope (SEM) images of shale samples. More than 20 locations are selected, typically 144 locations. High-resolution SEM images of these locations are obtained. During the imaging process of the selected organic matter development locations, the magnification is set to 10,000x, the image width is 27.5 μm, and the resolution is 6.75 nm.

[0291] The electron microscopy images of each organic matter development location were processed using image processing software, resulting in one organic matter area of ​​9.8 × 10⁻⁶. 7 nm 2 The organic pore area within the organic matter is 1.39 × 10⁻⁶. 7 nm 2 The porosity of a single organic matter particle was calculated. = (1.39 × 10 7 ) / (9.8×10 7 =14.15%.

[0292] The organic matter surface rates at the selected 144 organic matter development sites were summed:

[0293]

[0294] The cumulative value of the organic matter surface area ratio is processed to obtain the average surface area ratio of organic matter. =2227.68 / 144=15.47%.

[0295] For the figures in the above embodiments, please refer to the accompanying drawings in Embodiment 1.

[0296] In the detailed description above, various features are combined together in a single embodiment to simplify this disclosure. This approach to disclosure should not be construed as reflecting an intention that embodiments of the claimed subject matter require more features than are explicitly stated in each claim. Rather, as reflected in the appended claims, the invention is presented with fewer features than all of the features in a single disclosed embodiment. Therefore, the appended claims are hereby explicitly incorporated into the detailed description, with each claim representing a separate preferred embodiment of the invention.

[0297] The foregoing description includes examples of one or more embodiments. It is certainly impossible to describe all possible combinations of components or methods in order to describe the above embodiments, but those skilled in the art will recognize that further combinations and arrangements of the various embodiments are possible. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. Furthermore, the term “comprising” as used in the specification or claims is interpreted in a manner similar to the term “including,” just as “including,” is interpreted as a conjunction in the claims. Additionally, the use of any term “or” in the specification of the claims is intended to mean “non-exclusive or.”

Claims

1. A method for determining organic and inorganic porosity of shale, characterized by, The method comprises the following steps: obtaining shale total porosity by using a preset first rule; obtaining organic matter pore area ratio by using a preset third rule; obtaining a pore area conversion coefficient by using a preset fourth rule; obtaining shale organic matter porosity according to the organic matter pore area ratio and the pore area conversion coefficient by using the following formula: obtaining shale inorganic matter porosity according to the shale total porosity and the shale organic matter porosity by using the following formula: wherein, is the shale organic matter porosity; C sv is the surface porosity conversion factor; is the organic matter surface porosity, which is the organic matter porosity as a fraction of the total area, is the shale inorganic matter porosity; is the total shale porosity.

2. The method of claim 1, wherein, The method for obtaining shale total porosity by using a preset first rule comprises the following steps: putting a shale sample into a gas porosimeter, and removing air in the pores of the sample by vacuumizing; applying a certain pressure of helium gas into the pores without applying confining pressure; setting gas pressure and equilibrium time, and obtaining shale total porosity after pressure equilibrium.

3. The method of claim 1, wherein, The method for obtaining organic matter pore area ratio by using a preset third rule comprises the following steps: carrying out an electron microscope scanning experiment on the shale sample to obtain a first scanning electron microscope image of the shale sample; extracting all organic matter areas in the first scanning electron microscope image of the shale sample by using a preset image processing software to obtain a total area fraction of the shale sample surface occupied by organic matter; obtaining an average pore area ratio of organic matter pores according to the first scanning electron microscope image of the shale sample by using a preset fifth rule; obtaining the organic matter pore area ratio according to the total area fraction of the shale sample surface occupied by organic matter and the average pore area ratio of organic matter pores by using the following formula: wherein, is the average surface porosity of the organic matter pores; S ot is the total area fraction of all organic matter on the surface of the shale sample.

4. The method of claim 3, wherein, The method for carrying out an electron microscope scanning experiment on the shale sample to obtain a first scanning electron microscope image of the shale sample comprises the following steps: selecting a target layer shale sample to polish according to a preset area to obtain a polished shale sample; processing the surface of the polished shale sample according to a preset process to obtain a processed shale sample; putting the processed shale sample into a field emission scanning electron microscope to perform surface imaging; selecting a preset area of the processed shale sample; setting a continuous imaging mode of the scanning electron microscope to obtain a preset number of continuous scanning electron microscope images of the preset area; splicing the preset number of continuous scanning electron microscope images to generate a first scanning electron microscope image.

5. The method of claim 3, wherein, The method for obtaining an average pore area ratio of organic matter pores according to the first scanning electron microscope image of the shale sample by using a preset fifth rule comprises the following steps: selecting a preset number of shale organic matter development positions in the first scanning electron microscope image, and performing electron microscopy imaging of each selected shale organic matter development position according to a preset multiple and a preset area to generate a corresponding second scanning electron microscope image; identifying and processing organic matter pores in each second scanning electron microscope image to obtain an area of each organic matter pore and an area of each organic matter region; obtaining a pore area ratio of each organic matter pore to organic matter according to the area of each organic matter pore and the area of each organic matter region by using the following formula: obtaining an average pore area ratio of organic matter pores according to the pore area ratio of each organic matter pore to organic matter by using the following formula: wherein, the surface porosity of the organic matter for each organic matter pore; S opi the area of each organic matter pore; S orgi the area of each organic matter region; the average surface porosity of the organic matter pores; n is the number of selected shale organic matter development locations.

6. The method of claim 5, wherein, The method for identifying and processing organic matter pores in each second scanning electron microscope image to obtain an area of each organic matter pore and an area of each organic matter region comprises the following steps: The preset image processing software is used to identify the organic matter pores in each second scanning electron microscope image, so as to obtain each group of shale organic matter pores; The preset image processing software is used to color mark each group of shale organic matter pores, so as to obtain each group of shale organic matter pores with color marks; The preset software is used to process each group of shale organic matter pores with color marks, so as to obtain the area of each organic matter pore and the area of each organic matter region.

7. The method of claim 1, wherein, The preset fourth rule is used to obtain the surface pore rate conversion coefficient, including: The preset image processing software is used to extract all organic matter regions in the first scanning electron microscope image of the shale sample, so as to obtain the total area fraction of the shale sample surface organic matter; The preset sixth rule is used to obtain the volume fraction of the sample occupied by the organic matter; According to the total area fraction of the shale sample surface organic matter and the volume fraction of the sample occupied by the organic matter, the surface pore rate conversion coefficient is obtained according to the following formula: wherein, C sv is the surface area fraction of the shale sample occupied by the organic matter; V org is the volume fraction of the sample occupied by the organic matter; S ot is the total area fraction of the shale sample surface occupied by the organic matter.

8. The method of claim 7, wherein, The preset sixth rule is used to obtain the volume fraction of the sample occupied by the organic matter, including: According to the shale sample organic matter content, the shale sample density and the shale organic matter density, the volume fraction of the sample occupied by the organic matter is obtained according to the following formula: wherein, TOC is the organic matter content of the shale sample; p s is the density of the shale sample, g / cm 3 ; p org is the density of the organic matter of the shale, g / cm 3 .

9. A method of evaluating a hydrocarbon reservoir, characterized by, The shale inorganic porosity and organic porosity determination method includes any one of claims 1 to 8.

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