Shale gas dessert section compaction action strength evaluation method and reservoir quality evaluation method

Abstract

The invention provides a shale gas dessert section compaction action strength evaluation method and a reservoir quality evaluation method. The shale gas dessert section compaction effect strength evaluation method comprises the step of determining the compaction effect strength of organic matters in a target shale gas dessert section rock sample based on the organic pore and organic matter occurrence state of the target shale gas dessert section rock sample. The method for evaluating the reservoir quality of the shale gas dessert section comprises the following steps: determining the occurrence state of organic pores and organic matters of a rock sample of a target shale gas dessert section, and further determining the content of mesoporous organic matters and the content of pore-free organic clay composites in the rock sample of the target shale gas dessert section, and evaluating the reservoir quality of the target shale gas dessert section. According to the technical scheme provided by the invention, shale gas dessert section compaction effect strength evaluation and reservoir quality evaluation can be realized based on the organic hole and organic matter occurrence state, so that shale reservoir fine evaluation and shale gas efficient exploration and development are promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of shale oil and gas exploration and development, and specifically relates to a shale gas sweet spot section compaction intensity evaluation method and a reservoir quality evaluation method based on the occurrence state of organic pores and organic matter. Background Art

[0002] Resource-rich shale oil and gas have gradually become a key focus of oil and gas exploration and development. Honeycomb-shaped nano-organic pores, as the primary reservoir space and important seepage pathways for shale oil and gas, have attracted attention from the global oil and gas industry. The combined use of argon ion polishing, MAPS, and FIB techniques to characterize the occurrence of organic pores, including their morphology, size, and connectivity, has promoted the large-scale exploration and development of shale oil and gas. However, understanding of the occurrence of organic pores and organic matter is inconsistent and even contradictory.

[0003] Thermal simulation experiments on immature or low-maturity shale suggest that organic matter with organic pores is residual kerogen or pyroasphaltized petroleum. Thermal simulation experiments on petroleum "bubble-to-pore" have revealed that during the conversion of petroleum into pyroasphalt and natural gas, honeycomb-like nano-sized natural gas bubbles develop within the pyroasphalt. Researchers have combined argon ion polishing with high-resolution scanning electron microscopy to classify pores in shale reservoirs and have concluded that organic matter with organic pores is residual kerogen. Researchers using synchronized scanning transmission X-ray microscopy (STXM) have observed that pores in shale reservoirs develop within migrating organic matter, while in-situ organic matter lacks organic pores. A review of previous studies has found that it is generally believed that the types of organic matter in shale gas reservoirs are pyroasphalted kerogen (in situ organic matter) and pyroasphalted oil (migrated organic matter). Some researchers believe that pyroasphalted kerogen has honeycomb organic pores while pyroasphalted oil lacks organic pores, while other researchers believe that pyroasphalted kerogen lacks organic pores while pyroasphalted oil has honeycomb organic pores. These completely different views indicate that people have a unclear understanding of the occurrence state of organic pores and organic matter in shale gas reservoirs. At the same time, strong compaction can cause the organic pores to close and disappear, resulting in the persistence of "pyroasphalted kerogen with organic pores". Scholars who hold the view that "asphalt-bearing kerogen has honeycomb-shaped organic pores while pyroasphalt-bearing petroleum lacks organic pores" mistakenly believe that pyroasphalt-bearing kerogen whose pores have disappeared due to compaction is pyroasphalt-bearing petroleum, while scholars who hold the view that "asphalt-bearing kerogen lacks organic pores while pyroasphalt-bearing petroleum has honeycomb-shaped organic pores" mistakenly believe that pyroasphalt-bearing petroleum whose organic pores have disappeared due to compaction is pyroasphalt-bearing kerogen, resulting in confusion in the identification of organic pores and the occurrence status of organic matter. The combination of "unclear understanding of organic matter types" and "compaction causing confusion in organic matter types" has led to greater confusion in the understanding of organic pores, seriously affecting shale gas reservoir evaluation and efficient exploration and development.

[0004] In view of this, only by clarifying the relationship between the occurrence state of organic pores and organic matter and the intensity of compaction can we accurately achieve a detailed evaluation of shale gas reservoirs and thus guide the efficient exploration and development of shale gas.

[0005] Recently, researchers using the MAPS technique discovered in radiolarian siliceous shales with overmature organic matter that the organosilicon complexes within the radiolarian shell cavity and the organoclay complexes outside the radiolarian shell are transformed from sedimentary organosilicon complexes and sedimentary organoclay complexes (collectively referred to as sedimentary organic mineral complexes). Sedimentary organic matter thermally evolves into pyroasphalt and natural gas via kerogen, pre-oil asphalt, solid asphalt, and petroleum. Correspondingly, sedimentary organic mineral complexes transform into pyroasphalt complexes via kerogen mineral complexes, pre-oil asphalt mineral complexes, and solid asphalt mineral complexes. Pre-oil asphalt migrated from in situ organic matter thermally evolves into pyroasphalt and natural gas via solid asphalt and petroleum, while petroleum migrated from pre-oil asphalt transforms into pyroasphalt. Pyroasphalted organic mineral complexes and pyroasphalted solid asphalt develop organic pores, while pyroasphalted petroleum lacks organic pores. This clarifies the fundamental relationship between organic matter type and organic pores, providing the necessary prerequisite for the present analysis of the relationship between organic pores, organic matter occurrence state, and compaction intensity based on organic pores and organic matter occurrence.

[0006] In summary, there is still a need to study technical solutions for analyzing the compaction intensity of shale gas sweet spots based on the relationship between the occurrence state of organic pores and organic matter and the compaction intensity, so as to promote the detailed evaluation of shale reservoirs and the efficient exploration and development of shale gas. Summary of the Invention

[0007] The purpose of the present invention is to provide a technical solution that can realize the evaluation of the compaction intensity of shale gas sweet spots and reservoir quality based on the occurrence state of organic pores and organic matter, thereby promoting the detailed evaluation of shale reservoirs and the efficient exploration and development of shale gas.

[0008] In order to achieve the above objectives, the present invention provides the following two technical solutions.

[0009] In one aspect, the present invention provides a method for evaluating the compaction strength of a shale gas sweet spot, the method comprising:

[0010] Obtain rock samples from the target shale gas sweet spot;

[0011] Determine the organic pores and organic matter occurrence status of rock samples in the target shale gas sweet spot;

[0012] Determine the compaction intensity of organic matter in the rock samples of the target shale gas sweet spot based on the organic pores and organic matter occurrence state of the rock samples;

[0013] Among them, the compaction intensity of organic matter with rich macropore organic pores distributed inside the silica shell is low; the pure organic matter with rich macropore organic pores distributed outside the silica shell is insensitive to the compaction intensity; the pure organic matter with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell and the organic clay complex (i.e., the pure organic matter with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell and the organic clay complex with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell) is low. The compaction intensity of pure organic matter and organic clay complex with rich mesoporous organic pores (i.e. pure organic matter with rich mesoporous organic pores and organic clay complex with rich mesoporous organic pores) is medium; the compaction intensity of pure organic matter without pores is insensitive to the compaction intensity; the compaction intensity of organic clay complex with no pores is high; the compaction intensity of organic silicon particle complex with no pores is high.

[0014] In a second aspect, the present invention provides a method for evaluating the reservoir quality of a shale gas sweet spot, the method comprising:

[0015] Obtain rock samples from the target shale gas sweet spot;

[0016] Determine the occurrence state of organic pores and organic matter in rock samples of the target shale gas sweet spot, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot; wherein, mesoporous organic matter includes pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in mesoporous organic pores, as well as pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in macroporous organic pores and mesoporous organic pores;

[0017] The reservoir quality of the target shale gas sweet spot is evaluated based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot.

[0018] The technical solution provided by the present invention can realize the relationship between the occurrence state of organic pores and organic matter in shale gas sweet spots and the intensity of compaction, and evaluate the reservoir quality of shale gas sweet spots, thereby helping to reduce costs and increase efficiency in the economic goal of exploring and developing shale gas. Specifically: The present invention establishes a technical solution for judging the intensity of compaction based on the occurrence state of organic pores and organic matter in shale, providing scientific data support for layer selection in the shale gas exploration stage and fine sweet spot evaluation in the development stage. The present invention establishes a method for evaluating the reservoir quality of shale gas sweet spots based on the occurrence state of organic pores and organic matter in shale combined with the compaction constraint of shale gas sweet spots, providing important information for the selection of shale gas horizontal well targets and guiding the efficient exploration and development of shale gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1a This is a longitudinal section of the core in Example 1.

[0020] Figure 1b This is a diagram of the complete silica shell and its cavity calcite (Ca) and organic silicon particle complex in the target core sample in Example 1.

[0021] Figure 1c for Figure 1b Enlarged image of the organosilicone particle complex in the middle red frame.

[0022] Figure 1d This is a diagram of the complex of the incomplete silica shell and its cavity calcite (Ca) and organic silicon particles in the target core sample in Example 1.

[0023] Figure 1e for Figure 1d Enlarged image of the organosilicon particle complex at position ① in the middle red box.

[0024] Figure 1f for Figure 1d Enlarged image of the organosilicon particle complex at position ② in the middle red box.

[0025] Figure 1g for Figure 1d Enlarged image of the organosilicon particle complex at position ③ in the middle red box.

[0026] Figure 1h for Figure 1d Enlarged image of the organosilicon particle complex at position ④ in the middle red box.

[0027] Figure 1i This is a map of inter-skeletal organic matter in the target core sample in Example 1.

[0028] Figure 1j for Figure 1i An enlarged image of the organoclay complex at position ① in the middle red box.

[0029] Figure 1k for Figure 1iEnlarged image of pure organic matter at position ② in the middle red box.

[0030] Figure 11 This is a diagram of pure organic matter between the skeletons in the target core sample in Example 1.

[0031] Figure 1m This is a diagram of pure organic matter between the skeletons in the target core sample in Example 1.

[0032] Figure 1n This is a diagram of the complex of the incomplete silica shell and its cavity calcite (Ca) and organic silicon particles in the target core sample in Example 1.

[0033] Figure 1o for Figure 1n An enlarged image of the complex of calcite and organosilica particles at position ① in the middle red box.

[0034] Figure 1p This is a diagram of the organic clay complex between the skeleton particles in the target core sample in Example 1.

[0035] Figure 1q This is a diagram of the pure organic matter and banded organic clay complex between the skeletons of the target core sample in Example 1.

[0036] Figure 1r for Figure 1q An enlarged view of the pure organic matter and striped organic clay complex between the skeletons in the middle red frame.

[0037] Figure 1s This is a strip-shaped pure organic matter image with no pores between the skeletons of the target core sample in Example 1.

[0038] Figure 1t This is a diagram of the organic matter filling the intercrystalline pores of raspberry pyrite in the target core sample in Example 1.

[0039] Figure 1u for Figure 1t Enlarged image of the organic matter in the intercrystalline pores of berry-shaped pyrite in the middle red frame.

[0040] Figure 2a This is a longitudinal section of the core in Example 2.

[0041] Figure 2b This is a map of organic matter between skeleton particles in the target core sample in Example 2.

[0042] Figure 2c This is a map of organic matter between skeleton particles in the target core sample in Example 2.

[0043] Figure 2d This is a map of organic matter between skeleton particles in the target core sample in Example 2.

[0044] Figure 2eThis is a map of organic matter between skeleton particles in the target core sample in Example 2.

[0045] Figure 3a This is a longitudinal section of the core in Example 3.

[0046] Figure 3b This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0047] Figure 3c This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0048] Figure 3d This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0049] Figure 3e This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0050] Figure 3f This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0051] Figure 3g This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0052] Figure 3h This is a map of organic matter between skeleton particles in the target core sample in Example 3.

[0053] Figure 3i This is a map of organic matter between mineral particles in the target core sample in Example 3.

[0054] Figure 3j This is a map of organic matter between mineral particles in the target core sample in Example 3.

[0055] Figure 3k This is the organic matter map of the intercrystalline pores of berry-shaped pyrite in the target core sample in Example 3.

[0056] Figure 4a This is a longitudinal section of the core in Example 4.

[0057] Figure 4b This is a map of organic matter between mineral particles in the target core sample in Example 4.

[0058] Figure 4c This is a map of organic matter between mineral particles in the target core sample in Example 4.

[0059] Figure 4d This is a map of organic matter between mineral particles in the target core sample in Example 4.

[0060] Figure 4e This is a map of organic matter between mineral particles in the target core sample in Example 4.

[0061] Figure 4f This is the organic matter map of the intercrystalline pores of berry-shaped pyrite in the target core sample in Example 4. DETAILED DESCRIPTION

[0062] To make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below with reference to the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0063] MAPS stands for Modular Automated Processing System. MAPS technology divides the sample's argon ion polished surface into a series of regular grids, scans and images each grid, and stitches the images of all the grids together to obtain a two-dimensional large-field scan image data volume, which is the MAPS data volume.

[0064] The "phase surface method" is used to calculate the normalized content of mesoporous organic matter and non-porous organic clay complexes: the "phase surface method" estimates the volume percentage of mesoporous organic matter and non-porous organic clay complexes in each grid rock image in the 4nmMAPS data body. The volume percentage of mesoporous organic matter and non-porous organic clay complexes in different grid rock images are added together to obtain their volume percentage of mesoporous organic matter and non-porous organic clay complexes in all grids, and normalized to the volume percentage of mesoporous organic matter and non-porous organic clay complexes.

[0065] Silica shell refers to the silica shell of radiolaria; a complete silica shell refers to a silica shell in which more than two-thirds of the silica shell is preserved and more than two-thirds of the fillings in the silica shell cavity are preserved; an incomplete silica shell refers to a silica shell in which less than two-thirds of the silica shell is preserved and less than two-thirds of the fillings in the silica shell cavity are preserved.

[0066] Shell debris refers to the silica shell debris whose silica shell cavity fillings are not preserved.

[0067] Skeleton particles include rigid mineral particles such as quartz, calcite, dolomite, pyrite, etc., but do not include clay minerals (plastic mineral components). Among them, quartz includes biomass silicon (such as silica shells and shell fragments) and terrigenous quartz, and pyrite includes pyrite particles and raspberry pyrite.

[0068] Mineral particles include rigid mineral particles such as quartz, calcite, dolomite, pyrite, and clay minerals (plastic mineral components). Among them, quartz includes biomass silicon (such as silica shells and shell fragments) and terrigenous quartz, and pyrite includes pyrite particles and raspberry pyrite.

[0069] Lumpy organic matter refers to organic matter with a length-to-height ratio of ≤5, and strip-shaped organic matter refers to organic matter with a length-to-height ratio of >5.

[0070] Organic pores refer to pores developed in organic matter, organic clay complexes, or organic silica complexes.

[0071] Mesopores refer to pores with a pore diameter smaller than 50 nm and larger than 4 μm.

[0072] Macropores refer to pores with a pore diameter greater than or equal to 50 nm.

[0073] Organoclay complex refers to a complex formed by the mixing of organic matter and clay.

[0074] Organic silicon particle complex refers to a complex formed by the mixture of organic matter and silicon particles.

[0075] Pure organic matter refers to organic matter that is not mixed with minerals such as clay and silica particles.

[0076] Development of macropore-rich organic pores refers to the development of macropores with a pore density of not less than 3 pores / μm 2 .

[0077] Development of mesoporous organic pores refers to the development of mesopores with a pore density of not less than 3 pores / μm 2 .

[0078] The inventors of this invention analyzed the occurrence of organic pores and organic matter in shale gas sweet spots, clarifying the relationship between their occurrence and compaction intensity. Using the "face method," they calculated the normalized content of mesoporous organic matter and non-porous organic clay complexes in these sweet spots, characterized their compaction intensity, and evaluated their reservoir quality. This pioneered the use of compaction intensity characteristics to evaluate reservoir quality in shale gas sweet spots. This method, which constrains compaction intensity analysis based on the occurrence of organic pores and organic matter, reduces the ambiguity in the relationship between their occurrence and compaction intensity, thereby guiding efficient shale gas exploration and development. Furthermore, based on the inventors' research findings, the present invention provides a method for evaluating the compaction intensity of shale gas sweet spots and a method for evaluating reservoir quality in shale gas sweet spots, providing important information for selecting targets for shale gas horizontal wells and guiding efficient shale gas exploration and development.

[0079] In one embodiment, the present invention provides a method for evaluating the compaction strength of a shale gas sweet spot, the method comprising:

[0080] S1: Obtain rock samples from the target shale gas sweet spot;

[0081] S2: Determine the organic pores and organic matter occurrence status of rock samples in the target shale gas sweet spot;

[0082] S3: Determine the compaction intensity of organic matter in the rock samples of the target shale gas sweet spot based on the organic pores and organic matter occurrence state of the rock samples;

[0083] Among them, the compaction intensity of organic matter with rich macropore organic pores distributed inside the silica shell is low; the pure organic matter with rich macropore organic pores distributed outside the silica shell is insensitive to the compaction intensity; the pure organic matter with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell and the organic clay complex (i.e., the pure organic matter with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell and the organic clay complex with rich macropore organic pores and rich mesopore organic pores distributed outside the silica shell) is low. The compaction intensity of pure organic matter and organic clay complex with rich mesoporous organic pores (i.e. pure organic matter with rich mesoporous organic pores and organic clay complex with rich mesoporous organic pores) is medium; the compaction intensity of pure organic matter without pores is insensitive to the compaction intensity; the compaction intensity of organic clay complex with no pores is high; the compaction intensity of organic silicon particle complex with no pores is high.

[0084] For organic matter distributed in the silica shell with rich macropores (referring to organic matter distributed in the silica shell with a pore diameter of not less than 50 μm and a pore density of not less than 3 pores / μm 2 The organic pores and organic matter are derived from pyroasphalt with developed organic pores, which is converted from solid asphalt petroleum. The rock microregions where the organic pores and organic matter are located have a strong ability to resist compaction. The rock skeleton particles bear all the pressure of the overlying formations, and the organic matter does not bear the pressure of the overlying formations. The organic pores are protected and remain in their original state.

[0085] For the pure organic matter distributed outside the silica shell with rich macropores (referring to the organic matter distributed outside the silica shell with a pore diameter of not less than 50 μm and a pore density of not less than 3 pores / μm 2 The organic pores and organic matter are formed by pyroasphalt transformed from petroleum that wraps water droplets. The pyroasphalted petroleum has no pores, and the water droplets evaporate into water vapor to form organic pores. The rock microregions where the organic pores and organic matter are located are low compaction intensity microregions, medium compaction intensity microregions, or high compaction intensity microregions.

[0086] For the pure organic matter and organic clay complex distributed outside the silica shell and rich in macroporous organic pores and mesoporous organic pores (referring to the pores distributed outside the silica shell with a diameter greater than 50 μm and a pore density of not less than 3 pores / μm), 2 The organic pores and pores have a diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm 2The organic pores and organic matter are nested with each other. The origin of the organic pores and organic matter is pyroasphalt converted from solid asphalt petroleum wrapped in water droplets. The water droplets evaporate into water vapor to form macroporous organic pores. The pyroasphalted solid asphalt petroleum forms mesoporous organic pores under medium compaction intensity. The rock microregion where the organic pores and organic matter are located has the ability to resist medium compaction. The rock skeleton particles and organic pores and organic matter bear part of the overlying formation pressure respectively. The diameter of the organic pores formed by the vaporization of water droplets into water vapor is greater than 50μm and the pore density is not less than 3 pores / μm. 2 The overlying formation pressure causes the pore diameter of the pyroasphalted solid asphalt petroleum to transform from greater than 50 μm to less than 50 μm and greater than 4 μm, and the pore density does not change significantly.

[0087] For pure organic matter and organic clay complexes with rich mesoporous organic pores (pore diameter less than 50 μm and greater than 4 μm, pore density not less than 3 pores / μm), 2 Pure organic matter and pore diameter less than 50μm and greater than 4μm, pore density not less than 3 pores / μm 2 The organic pores and organic matter are originated from mesoporous organic pores formed by pyrobituminous solid asphalt petroleum under medium compaction intensity. The rock microregions where the organic pores and organic matter are located have the ability to resist medium compaction. The rock skeleton particles and the organic pores and organic matter respectively bear part of the overlying formation pressure, resulting in the pore diameter of the organic pores changing from greater than 50μm to less than 50μm and greater than 4μm, while the pore density has not changed significantly.

[0088] For pure organic matter without pores, its origin is pyroasphalt petroleum, which has no pores; the rock micro-region where the pure organic matter without pores is located is a low compaction intensity micro-region, a medium compaction intensity micro-region, or a high compaction intensity micro-region.

[0089] For the non-porous organic clay complex, its formation is the solid asphalt petroleum clay complex of pyroasphalt clay complex with high compaction strength; the rock micro-region where the non-porous organic clay complex is located has weak resistance to compaction, and the organic pores and organic matter bear all the overlying formation pressure like the mineral particles, resulting in the pore diameter of the solid asphalt petroleum clay complex of pyroasphalt clay complex greater than 50μm and the pore density not less than 3 pores / μm 2 The organic pores are crushed and disappear.

[0090] For the non-porous organic silicon particle complex, its formation is the solid asphalt petroleum silicon particle complex of pyroasphalt silicon particle complex with high compaction strength; the rock micro-region where the non-porous organic silicon particle complex is located has weak resistance to compaction, and the organic pores and organic matter bear all the overlying formation pressure like the mineral particles, resulting in the pore diameter of the solid asphalt petroleum silicon particle complex of pyroasphalt silicon particle complex greater than 50μm and the pore density not less than 3 pores / μm 2 The organic pores are crushed and disappear.

[0091] Furthermore, the organic matter distributed in the silicon shell and having developed macropore-rich organic pores also has the following occurrence characteristics: it is an organic silicon particle complex and / or a filling in the silicon shell cavity of a complete silicon shell.

[0092] Furthermore, the pure organic matter distributed outside the silica shell and rich in macroporous organic pores also has the following occurrence characteristics:

[0093] It exists in the form of clumps between mineral particles.

[0094] Furthermore, the pure organic matter and organic clay complex distributed outside the silica shell, which is rich in macroporous and mesoporous organic pores, also has the following occurrence characteristics:

[0095] It exists in the form of clumps between the particles of the rock skeleton.

[0096] Furthermore, the complex of pure organic matter and organic clay particles rich in mesoporous organic pores also has the following occurrence characteristics:

[0097] It exists in the form of lumps between the particles of the rock skeleton, or in the form of strips between the particles of the rock skeleton, or as fillings of the intercrystalline pores of berry-shaped pyrite, or as fillings in the silica shell cavity of a defective silica shell.

[0098] Furthermore, pure organic matter without pores also has the following occurrence characteristics:

[0099] It exists in the form of lumps between mineral particles, or in the form of strips between mineral particles, or as berry-like pyrite intercrystalline pore fillings.

[0100] Furthermore, the non-porous organoclay complex also has the following occurrence characteristics:

[0101] It exists between mineral particles in the form of lumps, strips, or impregnations.

[0102] Furthermore, the non-porous organosilicon particle composite also has the following characteristics:

[0103] It is the filling inside the silicon shell cavity of the incomplete silicon shell.

[0104] Furthermore, obtaining rock samples from the target shale gas sweet spot section includes:

[0105] The rock sample collected from the target shale gas sweet spot section is the target shale gas sweet spot section rock sample.

[0106] Furthermore, the organic pores and organic matter occurrence status of rock samples in the target shale gas sweet spot are determined, including:

[0107] Using the rock sample of the target shale gas sweet spot section to make the argon ion polished slice of the target shale gas sweet spot section rock;

[0108] Collect MAPS rock image data volumes of argon ion polished slices of target shale gas sweet spot rock;

[0109] Based on the MAPS rock image data volume of the argon ion polished slices of the target shale gas sweet spot section rock, the organic pores and organic matter occurrence status of the target shale gas sweet spot section rock samples are determined;

[0110] Furthermore, the resolution of the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock is 1-10nm resolution (for example, 4nm resolution);

[0111] Furthermore, the length of the argon ion polished slice of the target shale gas sweet spot rock is 0.8-2 cm (e.g., 1 cm);

[0112] Furthermore, the width of the argon ion polished slice of the target shale gas sweet spot rock is 0.8-2 cm (e.g., 1 cm);

[0113] Furthermore, the thickness of the argon ion polished slice of the target shale gas sweet spot rock is 0.3-0.8 cm (e.g., 0.5 cm);

[0114] Furthermore, the top and bottom surfaces of the argon ion polished slice of the target shale gas sweet spot are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in its underground state, thereby better revealing the underground state information of the rock and better ensuring that the observed microscopic phenomena are merely an amplification of the underground state of the rock;

[0115] Furthermore, collecting a MAPS rock image data volume of an argon ion polished sheet of rock in the target shale gas sweet spot includes: selecting an area with a length and a width not exceeding 400 μm on a polished surface of the argon ion polished sheet of rock in the target shale gas sweet spot, and collecting the MAPS rock image data volume;

[0116] Furthermore, in the process of collecting the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock, the top surface of the argon ion polished slice of the target shale gas sweet spot section rock is located above the field of view, and the bottom surface of the argon ion polished slice of the target shale gas sweet spot section rock is located below the field of view, thereby ensuring that all phenomena observed in the collected MAPS rock image data volume are merely amplifications of natural phenomena.

[0117] In one embodiment, the method for evaluating the reservoir quality of a shale gas sweet spot provided by the present invention includes:

[0118] Obtain rock samples from the target shale gas sweet spot;

[0119] Determine the occurrence state of organic pores and organic matter in rock samples of the target shale gas sweet spot, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot; wherein, mesoporous organic matter includes pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in mesoporous organic pores, as well as pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in macroporous organic pores and mesoporous organic pores;

[0120] The reservoir quality of the target shale gas sweet spot is evaluated based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot.

[0121] Furthermore, based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot, the reservoir quality of the target shale gas sweet spot is evaluated including:

[0122] When the content of mesoporous organic matter in the rock sample of the target shale gas sweet spot and the non-porous organic clay complex is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot presents the characteristics of medium compaction intensity and is a high-quality reservoir.

[0123] When the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot is less than 95% and greater than or equal to 50%, and the content of non-porous organic clay complexes is greater than 5% and less than or equal to 50%, the target shale gas sweet spot presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot is a general reservoir;

[0124] When the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complexes is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents a high compaction intensity to a medium compaction intensity characteristic, and the target shale gas sweet spot is a poor reservoir;

[0125] When the content of mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot is less than 5% and the content of non-porous organic clay complexes is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity and is a non-reservoir.

[0126] The target shale gas sweet spot section is a high-quality reservoir, and general reservoirs are suitable as targets for shale gas horizontal wells.

[0127] Furthermore, obtaining rock samples from the target shale gas sweet spot section includes:

[0128] The rock sample collected from the target shale gas sweet spot section is the target shale gas sweet spot section rock sample.

[0129] Furthermore, the occurrence state of organic pores and organic matter in the rock samples of the target shale gas sweet spot section is determined, and then the content of mesoporous organic matter and the content of non-porous organic clay complex in the rock samples of the target shale gas sweet spot section is determined, including:

[0130] Using the rock sample of the target shale gas sweet spot section to make the argon ion polished slice of the target shale gas sweet spot section rock;

[0131] Collect MAPS rock image data volumes of argon ion polished slices of target shale gas sweet spot rock;

[0132] Based on the MAPS rock image data volume of the argon ion polished slices of the target shale gas sweet spot section rock, the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock samples are determined, and then the content of mesoporous organic matter and non-porous organic clay complexes in the target shale gas sweet spot section rock samples are calculated;

[0133] Furthermore, the “face-to-face method” was used to statistically analyze the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot;

[0134] Furthermore, the resolution of the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock is 1-10nm resolution (preferably 4nm resolution);

[0135] Furthermore, the length of the argon ion polished slice of the target shale gas sweet spot rock is 0.8-2 cm (e.g., 1 cm);

[0136] Furthermore, the width of the argon ion polished slice of the target shale gas sweet spot rock is 0.8-2 cm (e.g., 1 cm);

[0137] Furthermore, the thickness of the argon ion polished slice of the target shale gas sweet spot rock is 0.3-0.8 cm (e.g., 0.5 cm);

[0138] Furthermore, the top and bottom surfaces of the argon ion polished slice of the target shale gas sweet spot are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in its underground state, thereby better revealing the underground state information of the rock and better ensuring that the observed microscopic phenomena are merely an amplification of the underground state of the rock;

[0139] Furthermore, collecting a MAPS rock image data volume of an argon ion polished sheet of rock in the target shale gas sweet spot includes: selecting an area with a length and a width not exceeding 400 μm on a polished surface of the argon ion polished sheet of rock in the target shale gas sweet spot, and collecting the MAPS rock image data volume;

[0140] Furthermore, in the process of collecting the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock, the top surface of the argon ion polished slice of the target shale gas sweet spot section rock is located above the field of view, and the bottom surface of the argon ion polished slice of the target shale gas sweet spot section rock is located below the field of view, thereby ensuring that all phenomena observed in the collected MAPS rock image data volume are merely amplifications of natural phenomena.

[0141] Example 1:

[0142] This embodiment provides a method for evaluating the compaction strength of a shale gas sweet spot and a method for evaluating the reservoir quality of a shale gas sweet spot.

[0143] The evaluation method for the compaction strength of shale gas sweet spots includes:

[0144] 1. Obtain rock samples from the target shale gas sweet spot.

[0145] In this example, a longitudinal section of a core sampled from the gas sweetspot of shale A in area A was observed, revealing a 2.5 mm thick radiolarian siliceous shale laminae, which appeared as a layer of white spots the size of a pen tip in the black shale without any fabric (e.g., Figure 1a The radiolarian siliceous shale laminae rock sample was taken as the target shale gas sweet spot rock sample.

[0146] 2. Use the target shale gas sweet spot rock sample to make an argon ion polishing sheet of the target shale gas sweet spot rock; the argon ion polishing sheet is 1 cm long, 1 cm wide, and 0.5 cm thick; the top and bottom surfaces of the argon ion polishing sheet are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state, respectively.

[0147] 3. Collect 4nm resolution MAPS rock image data from the polished surface of the argon ion polishing wafer in the target shale gas sweet spot. During the acquisition of the MAPS rock image data, the top surface of the argon ion polishing wafer is located above the field of view, and the bottom surface is located below the field of view, thereby ensuring that all phenomena observed in the acquired MAPS rock image data are merely amplifications of natural phenomena.

[0148] 4. Collect the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock to determine the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample; based on the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample, determine the compaction intensity of the organic matter in the target shale gas sweet spot section rock sample;

[0149] Among them, if the organic matter is distributed inside the silica shell and is rich in macroporous organic pores, then the organic matter is organic matter with low compaction intensity; if the organic matter is pure organic matter distributed outside the silica shell and is rich in macroporous organic pores, then the organic matter is unrelated to the compaction intensity; if the organic matter is a pure organic matter and organic clay complex distributed outside the silica shell and is rich in macroporous organic pores and mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter and organic clay complex rich in mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter without pores, then the organic matter is unrelated to the compaction intensity; if the organic clay complex without pores, then the organic matter is organic matter with high compaction intensity; if the organic silica particle complex without pores, then the organic matter is organic matter with high compaction intensity.

[0150] In this example, based on the MAPS rock image data of the argon ion polished slice of the target shale gas sweet spot section, it was observed that the target shale gas sweet spot section rock is composed of a complete silica shell and its cavity fillings, a broken silica shell and its cavity fillings, and shell debris, which are composed of the main skeleton of the rock. The skeleton particles are filled with organic matter, clay, and pyrite. The strong filling of the complete silica shell is a complex of calcite and organic silicon particles (such as Figure 1b The incomplete silica shell cavity is filled with a composite of calcite and organic silica particles (as shown in Figure 1d 、 Figure 1n The organic matter filling the space between the skeleton particles is pure organic matter (as shown in Figure 1i Organic matter outside the green circle, Figure 11、 Figure 1m 、 Figure 1r The red arrow points to Figure 1s ) and organoclay complexes (as shown Figure 1i Organic matter within the green circle, Figure 1p 、 Figure 1r The clay between the skeleton particles is in the form of agglomerated organic clay complexes (as indicated by the blue arrows); Figure 1i Organic matter within the green circle shown) or in the form of strip-like organic clay complexes ( Figure 1p 、 Figure 1r The pyrite filling between the skeletons can be divided into pyrite particles (such as Figure 1q 、 Figure 1r There are pyrites (such as Figure 1t (as shown) exists; intercrystalline pores of strawberry pyrite are filled with organic matter (as shown Figure 1t 、 Figure 1u Specifically:

[0151] In this example, the target shale gas sweet spot rock development: (1) organic matter filling the complete silica shell cavity (such as Figure 1b 、 Figure 1c (2) Organic matter filling the incomplete silica shell cavity (as shown in Figure 1d As shown in the figure, part of the organic matter is organic matter with medium compaction intensity (such as Figure 1e 、 Figure 1f The other part of the organic matter is organic matter with high compaction intensity (such as Figure 1g 、 Figure 1h (3) organic matter filling the incomplete silica shell cavity (as shown in Figure 1n 、 Figure 1o (4) Organic matter between skeleton particles (such as Figure 1i-1l 、 Figure 1r (5) Organic matter between skeleton particles (such as Figure 1m 、 Figure 1s (6) The organic clay complex between the skeleton particles (such as Figure 1p 、 Figure 1r The organic clay complex is organic matter with high compaction strength (as indicated by the blue arrow); (7) the organic matter filling the intercrystalline pores of raspberry pyrite (such as Figure 1t 、 Figure 1u This organic matter has a medium compaction intensity.

[0152] In this embodiment, the organic matter with low compaction strength in the target shale gas sweet spot is specifically the organic matter filling the complete silica shell cavity. The specific occurrence state of the organic matter filling the complete silica shell cavity is as follows: Figure 1b 、 Figure 1c As shown, the complete silica shell cavity filling is a complex of calcite (Ca) and organic silicon particles. The diameter of the organic silicon particle complex is not less than 50 μm and the density is not less than 3 pores / μm. 2 The organic matter is essentially a composite of pyroasphalt silica particles and solid asphalt petroleum silica particles, which has not been significantly affected by compaction and the pores remain in their original state.

[0153] In this example, the medium compaction strength organic matter developed in the target shale gas sweet spot includes organic matter partially filling the incomplete silica shell cavity, organic matter between some skeleton particles, and organic matter filling the intercrystalline pores of raspberry pyrite. Its specific occurrence state is described as follows. The organic matter partially filling the incomplete silica shell cavity is an organic silicon particle complex with a pore diameter of less than 50μm and greater than 4μm, and a pore density of not less than 3 pores / μm. 2 Organic pores (such as Figure 1e 、 Figure 1f The organic matter between the skeleton particles in this part is developed with diameter less than 50μm and larger than 4μm, and density not less than 3 pores / μm. 2 Pure organic matter of organic pores (such as Figure 1i Organic matter outside the green coil, Figure 1k 、 Figure 11 、 Figure 1r Red arrows indicate) and organoclay complexes ( Figure 1i Organic matter within the green coil, Figure 1j The organic matter filling the intercrystalline pores of raspberry pyrite is a pore with a diameter of less than 50 μm and greater than 4 μm, and a density of not less than 3 pores / μm. 2 Pure organic matter of organic pores (such as Figure 1t 、 Figure 1u The pores in the organic matter are present in the form of coke-asphalted solid asphalt petroleum with a diameter greater than 50 μm and a density of not less than 3 pores / μm. 2 The manifestation of organic pores under medium compaction intensity.

[0154] In this embodiment, the high compaction strength organic matter developed in the target shale gas sweet spot section rock includes organic clay complexes partially filling the incomplete silica shell cavity and part of the skeleton particles. Its specific occurrence state is as follows. The organic clay complex partially filling the incomplete silica shell cavity shows that some of the organic clay complexes have no pores (such as Figure 1d 、 Figure 1g 、 Figure 1h As shown) or the entire organic silicon particle composite has no pores (as shown Figure 1n 、 Figure 1o The organic clay complex between the skeleton particles in this part has no pores and exists in agglomerates (as shown in Figure 1p as shown) or in the form of stripes (as Figure 1q 、 Figure 1r (As indicated by the blue arrows). The organic silicon particle complex filling the incomplete silicon shell cavity is a high-compaction-strength pyroasphalt silicon particle complex-solid asphalt petroleum silicon particle complex. The organic clay particle complex between the skeleton particles is a high-compaction-strength pyroasphalt clay particle complex-solid asphalt petroleum clay particle complex. Under high-compaction strength, the pore diameter of the pyroasphalt solid asphalt petroleum is greater than 50μm and the pore density is not less than 3 pores / μm. 2 The organic pores are crushed and disappear.

[0155] In this embodiment, the organic matter developed in the target shale gas sweet spot section rock that is not related to the intensity of compaction is the pure organic matter between some skeleton particles, and its specific occurrence state is as follows. The pure organic matter between some skeleton particles is free of pores and exists in agglomerates or stripes. Figure 1m As shown, the non-porous strip-shaped pure organic matter between the skeleton particles is as follows Figure 1s The pure organic matter without pores between the skeleton particles is the pyroasphalt petroleum which is originally without pores and has nothing to do with the intensity of compaction.

[0156] Methods for evaluating reservoir quality in shale gas sweet spots include:

[0157] 1. Obtain a rock sample from the A shale gas sweet spot in Area A as the target shale gas sweet spot rock sample. Use the target shale gas sweet spot rock sample to prepare an argon ion polished wafer of the target shale gas sweet spot rock. Select an area on the polished surface of the argon ion polished wafer of the target shale gas sweet spot rock with a length and width not exceeding 400 μm. Collect a MAPS rock image data volume with a resolution of 4 nm.

[0158] Here, the MAPS rock image data volume obtained in step 3 of the shale gas sweet spot compaction strength evaluation method in Example 1 can be directly used.

[0159] 2. Based on the collected MAPS rock image data volume, determine the organic pores and organic matter occurrence status of the target shale gas sweet spot rock samples, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the target shale gas sweet spot rock samples; among them, mesoporous organic matter includes pure organic matter and organic clay complexes with rich mesoporous organic pores distributed outside the silica shell, as well as organic matter with rich mesoporous organic pores in pure organic matter and organic clay complexes distributed outside the silica shell.

[0160] In this embodiment, the content of mesoporous organic matter and non-porous organic clay complex in the target shale gas sweet spot rock sample is 68%, and the content of non-porous organic clay complex is 32%.

[0161] 3. Evaluate the reservoir quality of the target shale gas sweet spot based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot;

[0162] Among them, when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot section presents the characteristics of medium compaction intensity, and the target shale gas sweet spot section is a high-quality reservoir; when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is less than 95% and greater than or equal to 50% and the content of the non-porous organic clay complex is greater than 5% and less than or equal to 50%, the target shale gas sweet spot section presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot section is a general reservoir. layer; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complex is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity to medium compaction intensity, and the target shale gas sweet spot is a poor reservoir; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 5% and the content of non-porous organic clay complex is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity, and the target shale gas sweet spot is a non-reservoir.

[0163] In this embodiment, the content of mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot section is 68%, and the content of non-porous organic clay complexes is 32%. Therefore, the target shale gas sweet spot section has a medium to high compaction intensity characteristic, and the target shale gas sweet spot section is evaluated as a general reservoir.

[0164] Example 2

[0165] This embodiment provides a method for evaluating the compaction strength of a shale gas sweet spot and a method for evaluating the reservoir quality of a shale gas sweet spot.

[0166] The evaluation method for the compaction strength of shale gas sweet spots includes:

[0167] 1. Obtain rock samples from the target shale gas sweet spot.

[0168] In this embodiment, the longitudinal section of the core collected from the gas sweet spot section of shale B in area A was observed, and it was found that the core was black shale without any structure (such as Figure 2a Select one of them as the target shale gas sweet spot rock sample.

[0169] 2. Use the target shale gas sweet spot rock sample to make an argon ion polishing sheet of the target shale gas sweet spot rock; the argon ion polishing sheet is 1 cm long, 1 cm wide, and 0.5 cm thick; the top and bottom surfaces of the argon ion polishing sheet are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state, respectively.

[0170] 3. Collect 4nm resolution MAPS rock image data from the polished surface of the argon ion polishing wafer in the target shale gas sweet spot. During the acquisition of the MAPS rock image data, the top surface of the argon ion polishing wafer is located above the field of view, and the bottom surface is located below the field of view, thereby ensuring that all phenomena observed in the acquired MAPS rock image data are merely amplifications of natural phenomena.

[0171] 4. Collect the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock to determine the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample; based on the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample, determine the compaction intensity of the organic matter in the target shale gas sweet spot section rock sample;

[0172] Among them, if the organic matter is distributed inside the silica shell and is rich in macroporous organic pores, then the organic matter is organic matter with low compaction intensity; if the organic matter is pure organic matter distributed outside the silica shell and is rich in macroporous organic pores, then the organic matter is unrelated to the compaction intensity; if the organic matter is a pure organic matter and organic clay complex distributed outside the silica shell and is rich in macroporous organic pores and mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter and organic clay complex rich in mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter without pores, then the organic matter is unrelated to the compaction intensity; if the organic clay complex without pores, then the organic matter is organic matter with high compaction intensity; if the organic silica particle complex without pores, then the organic matter is organic matter with high compaction intensity.

[0173] In this example, based on the MAPS rock image data of the target shale argon ion polished film, it was observed that the target shale gas sweet spot segment rock has biomass silicon as the main rock skeleton, and the skeleton particles are filled with organic matter; the organic matter between the skeleton particles has a pore diameter of less than 50μm and greater than 4μm, and a pore density of not less than 3 pores / μm. 2 of pure organic matter in agglomerate form (such as Figure 2b 、 Figure 2c 、 Figure 2d organic matter within the white circle) and pure organic matter in the form of lumps without pores (such as Figure 2d Organic matter outside the white coil, Figure 2e shown).

[0174] Specifically:

[0175] In this example, the target shale gas sweet spot rock development is: (1) the organic matter between the skeleton particles has a pore diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm 2 of pure organic matter in agglomerate form (such as Figure 2b 、 Figure 2c 、 Figure 2d (2) Pure organic matter in the form of lumps without pores between the skeleton particles (such as Figure 2d Organic matter outside the white coil, Figure 2e This organic matter is independent of the intensity of compaction.

[0176] In this embodiment, the organic matter with medium compaction strength developed in the target shale gas sweet spot is specifically part of the organic matter between the skeleton particles, that is, the coke-asphalted solid asphalt petroleum with medium compaction strength, and its specific occurrence state is as follows. Figure 2b 、 Figure 2c 、 Figure 2d The organic matter within the white circle is pure organic matter, with pore diameters less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm. 2 Organic pores exist in the form of clusters.

[0177] In this embodiment, the organic matter that is not related to the intensity of compaction in the target shale gas sweet spot is specifically part of the organic matter between the skeleton particles, that is, the pyroasphalt oil that is not related to the intensity of compaction. Its specific occurrence state is as follows. Figure 2d Organic matter outside the white coil, Figure 2e (shown) is pure organic matter, without pores, and exists in agglomerates.

[0178] Methods for evaluating reservoir quality in shale gas sweet spots include:

[0179] 1. Obtain a rock sample from the shale gas sweet spot section B in Area A as the target shale gas sweet spot rock sample. Use the target shale gas sweet spot rock sample to prepare an argon ion polished wafer of the target shale gas sweet spot rock. Select an area on the polished surface of the argon ion polished wafer of the target shale gas sweet spot rock with a length and width not exceeding 400 μm. Collect a MAPS rock image data volume with a resolution of 4 nm.

[0180] Here, the MAPS rock image data volume obtained in step 3 of the shale gas sweet spot compaction strength evaluation method in Example 2 can be directly used.

[0181] 2. Based on the collected MAPS rock image data volume, determine the organic pores and organic matter occurrence status of the target shale gas sweet spot rock samples, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the target shale gas sweet spot rock samples; among them, mesoporous organic matter includes pure organic matter and organic clay complexes with rich mesoporous organic pores distributed outside the silica shell, as well as organic matter with rich mesoporous organic pores in pure organic matter and organic clay complexes distributed outside the silica shell.

[0182] In this embodiment, the content of mesoporous organic matter and non-porous organic clay complex in the target shale gas sweet spot rock sample is 100%, and the content of non-porous organic clay complex is 0%.

[0183] 3. Evaluate the reservoir quality of the target shale gas sweet spot based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot;

[0184] Among them, when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot section presents the characteristics of medium compaction intensity, and the target shale gas sweet spot section is a high-quality reservoir; when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is less than 95% and greater than or equal to 50% and the content of the non-porous organic clay complex is greater than 5% and less than or equal to 50%, the target shale gas sweet spot section presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot section is a general reservoir. layer; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complex is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity to medium compaction intensity, and the target shale gas sweet spot is a poor reservoir; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 5% and the content of non-porous organic clay complex is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity, and the target shale gas sweet spot is a non-reservoir.

[0185] In this embodiment, the content of mesoporous organic matter in the mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot section is 100%, and the content of non-porous organic clay complexes is 0%. Therefore, the target shale gas sweet spot section has a medium compaction intensity characteristic and is a high-quality reservoir.

[0186] Example 3

[0187] This embodiment provides a method for evaluating the compaction strength of a shale gas sweet spot and a method for evaluating the reservoir quality of a shale gas sweet spot.

[0188] The evaluation method for the compaction strength of shale gas sweet spots includes:

[0189] 1. Obtain rock samples from the target shale gas sweet spot.

[0190] In this example, the longitudinal section of the core collected from the shale gas sweet spot section C in area A was observed, and it was found that the core was black shale without any structure (such as Figure 3a Select one of them as the target shale gas sweet spot rock sample.

[0191] 2. Use the target shale gas sweet spot rock sample to make an argon ion polishing sheet of the target shale gas sweet spot rock; the argon ion polishing sheet is 1 cm long, 1 cm wide, and 0.5 cm thick; the top and bottom surfaces of the argon ion polishing sheet are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state, respectively.

[0192] 3. Collect 4nm resolution MAPS rock image data from the polished surface of the argon ion polishing wafer in the target shale gas sweet spot. During the acquisition of the MAPS rock image data, the top surface of the argon ion polishing wafer is located above the field of view, and the bottom surface is located below the field of view, thereby ensuring that all phenomena observed in the acquired MAPS rock image data are merely amplifications of natural phenomena.

[0193] 4. Collect the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock to determine the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample; based on the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample, determine the compaction intensity of the organic matter in the target shale gas sweet spot section rock sample;

[0194] Among them, if the organic matter is distributed inside the silica shell and is rich in macroporous organic pores, then the organic matter is organic matter with low compaction intensity; if the organic matter is pure organic matter distributed outside the silica shell and is rich in macroporous organic pores, then the organic matter is unrelated to the compaction intensity; if the organic matter is a pure organic matter and organic clay complex distributed outside the silica shell and is rich in macroporous organic pores and mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter and organic clay complex rich in mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter without pores, then the organic matter is unrelated to the compaction intensity; if the organic clay complex without pores, then the organic matter is organic matter with high compaction intensity; if the organic silica particle complex without pores, then the organic matter is organic matter with high compaction intensity.

[0195] In this example, based on the MAPS rock image data volume of the target shale gas sweet spot section rock obtained by argon ion polishing, the following observations were made: organic matter between the skeleton particles of the target shale gas sweet spot section rock, organic matter between mineral particles, and organic matter in the intercrystalline pores of raspberry pyrite. Among them, the organic matter between the skeleton particles has a pore diameter greater than 50 μm and a pore density of not less than 3 pores / μm. 2 Pure organic matter (such as Figure 3b As shown), and having a pore diameter greater than 50 μm and a pore density of not less than 3 pores / μm 2 The organic pores and pores have a diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm 2 Pure organic matter with nested organic pores (such as Figure 3c ) and organoclay complexes (as shown Figure 3d As shown), and having a pore diameter of less than 50 μm and greater than 4 μm, a pore density of not less than 3 pores / μm 2 Pure organic matter (such as Figure 3e) and organoclay complexes (as shown Figure 3f ), and non-porous agglomerated pure organic matter (as Figure 3g as shown) and strip-shaped pure organic matter (as shown Figure 3h Among them, the organic matter between mineral particles is a non-porous organic clay complex (such as Figure 3i 、 Figure 3j The intercrystalline organic matter of raspberry pyrite has a pore diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm. 2 Pure organic matter (such as Figure 3k Specifically:

[0196] In this example, the target shale gas sweet spot rock development is: (1) the organic matter between the skeleton particles has pores with a diameter greater than 50 μm and a pore density of not less than 3 pores / μm 2 Pure organic matter (such as Figure 3b (2) The organic matter between the skeleton particles has a pore diameter greater than 50 μm and a pore density of not less than 3 pores / μm. 2 The organic pores and pores have a diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm 2 Pure organic matter with nested organic pores (such as Figure 3c ) and organoclay complexes (as shown Figure 3d (3) The organic matter between the skeleton particles has a pore diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm. 2 Pure organic matter (such as Figure 3e ) and organoclay complexes (as shown Figure 3f (4) The organic matter between the skeleton particles is a mass of pure organic matter without pores (such as Figure 3g as shown) and strip-shaped pure organic matter (as shown Figure 3h (5) The organic matter between mineral particles is an impregnated organic clay complex with no pores (such as Figure 3i 、 Figure 3j (6) The intercrystalline pore organic matter of raspberry pyrite has a pore diameter of less than 50 μm and greater than 4 μm, and a pore density of not less than 3 pores / μm. 2 Pure organic matter (such as Figure 3k This organic matter has a medium compaction intensity.

[0197] In this embodiment, the organic matter developed in the target shale gas sweet spot section rock that is not related to the intensity of compaction specifically includes some pure organic matter between the skeleton particles, and its specific occurrence state is described as follows. A portion of the pure organic matter between the skeleton particles is free of pores and exists in the form of lumps or strips (e.g., Figure 3g The other part has a pore density of not less than 3 pores / μm. 2 , organic pores with diameters greater than 50 μm (such as Figure 3b The water droplets are vaporized into water vapor to form pores with a diameter greater than 50 μm and a pore density of not less than 3 pores / μm. 2 of organic pores.

[0198] In this example, the medium compaction strength organic matter developed in the target shale gas sweet spot includes some intergranular organic matter and organic matter filling the intercrystalline pores of raspberry pyrite. Its specific occurrence state is described as follows. A portion of the intergranular organic matter has a diameter greater than 50 μm and a pore density of not less than 3 pores / μm. 2 The organic pores have a diameter less than 50 μm and greater than 4 μm, and a density of not less than 3 pores / μm. 2 Pure organic matter and organic clay complexes with inter-nested organic pores (e.g. Figure 3c 、 3d As shown in the figure, it is essentially a solid asphalt petroleum with medium compaction strength, which is wrapped in water droplets. The water droplets are vaporized into water vapor to form a pore with a diameter greater than 50μm and a pore density of not less than 3 pores / μm. 2 The organic pores of the coke asphalt solid asphalt petroleum under medium compaction intensity are pores with a diameter of less than 50μm and greater than 4μm, and a density of not less than 3 pores / μm. 2 The other part of the organic matter between the skeleton particles has a diameter of less than 50μm and greater than 4μm, with a density of not less than 3 pores / μm 2 Pure organic matter of organic pores (such as Figure 3e ) and organoclay complexes (as shown Figure 3f The organic matter filling the intercrystalline pores of raspberry pyrite is pure organic matter, with a development diameter of less than 50μm and greater than 4μm, and a density of not less than 3 pores / μm. 2 Organic pores (such as Figure 3k shown).

[0199] In this embodiment, the organic matter with high compaction strength developed in the target shale gas sweet spot is specifically the organic matter between mineral particles, and its specific occurrence state is as follows. The organic matter between mineral particles is specifically an organic clay complex, which has no pores and is distributed in a disseminated manner between mineral particles (such as Figure 3i 、 Figure 3j As shown), it is essentially a pyroasphalt clay complex solid asphalt petroleum clay complex with high compaction strength.

[0200] Methods for evaluating reservoir quality in shale gas sweet spots include:

[0201] 1. Obtain a rock sample from the shale gas sweet spot section C in Area A as the target shale gas sweet spot rock sample. Use the target shale gas sweet spot rock sample to prepare an argon ion polished section of the target shale gas sweet spot rock. Select an area on the polished surface of the argon ion polished section of the target shale gas sweet spot rock with a length and width not exceeding 400 μm. Collect a MAPS rock image data volume with a resolution of 4 nm.

[0202] Here, the MAPS rock image data volume obtained in step 3 of the shale gas sweet spot compaction strength evaluation method in Example 3 can be directly used.

[0203] 2. Based on the collected MAPS rock image data volume, determine the organic pores and organic matter occurrence status of the target shale gas sweet spot rock samples, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the target shale gas sweet spot rock samples; among them, mesoporous organic matter includes pure organic matter and organic clay complexes with rich mesoporous organic pores distributed outside the silica shell, as well as organic matter with rich mesoporous organic pores in pure organic matter and organic clay complexes distributed outside the silica shell.

[0204] In this embodiment, the content of mesoporous organic matter and non-porous organic clay complex in the target shale gas sweet spot rock sample is 31%, and the content of non-porous organic clay complex is 69%.

[0205] 3. Evaluate the reservoir quality of the target shale gas sweet spot based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot;

[0206] Among them, when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot section presents the characteristics of medium compaction intensity, and the target shale gas sweet spot section is a high-quality reservoir; when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is less than 95% and greater than or equal to 50% and the content of the non-porous organic clay complex is greater than 5% and less than or equal to 50%, the target shale gas sweet spot section presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot section is a general reservoir. layer; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complex is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity to medium compaction intensity, and the target shale gas sweet spot is a poor reservoir; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 5% and the content of non-porous organic clay complex is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity, and the target shale gas sweet spot is a non-reservoir.

[0207] In this embodiment, the content of mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot section is 31%, and the content of non-porous organic clay complexes is 69%. Therefore, the target shale gas sweet spot section has a high compaction intensity to medium compaction intensity characteristic, and the target shale gas sweet spot section is a poor reservoir.

[0208] Example 4

[0209] A method for evaluating the compaction strength of a shale gas sweet spot and a method for evaluating the reservoir quality of a shale gas sweet spot.

[0210] The evaluation method for the compaction strength of shale gas sweet spots includes:

[0211] 1. Obtain rock samples from the target shale gas sweet spot.

[0212] In this example, the longitudinal section of the core collected from the D shale gas sweet spot in area A was observed, and it was found that the core was black shale without any structure (such as Figure 4a Select one of them as the target shale gas sweet spot rock sample.

[0213] 2. Use the target shale gas sweet spot rock sample to make an argon ion polishing sheet of the target shale gas sweet spot rock; the argon ion polishing sheet is 1 cm long, 1 cm wide, and 0.5 cm thick; the top and bottom surfaces of the argon ion polishing sheet are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state, respectively.

[0214] 3. Collect 4nm resolution MAPS rock image data from the polished surface of the argon ion polishing wafer in the target shale gas sweet spot. During the acquisition of the MAPS rock image data, the top surface of the argon ion polishing wafer is located above the field of view, and the bottom surface is located below the field of view, thereby ensuring that all phenomena observed in the acquired MAPS rock image data are merely amplifications of natural phenomena.

[0215] 4. Collect the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock to determine the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample; based on the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock sample, determine the compaction intensity of the organic matter in the target shale gas sweet spot section rock sample;

[0216] Among them, if the organic matter is distributed inside the silica shell and is rich in macroporous organic pores, then the organic matter is organic matter with low compaction intensity; if the organic matter is pure organic matter distributed outside the silica shell and is rich in macroporous organic pores, then the organic matter is unrelated to the compaction intensity; if the organic matter is a pure organic matter and organic clay complex distributed outside the silica shell and is rich in macroporous organic pores and mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter and organic clay complex rich in mesoporous organic pores, then the organic matter is organic matter with medium compaction intensity; if the organic matter is pure organic matter without pores, then the organic matter is unrelated to the compaction intensity; if the organic clay complex without pores, then the organic matter is organic matter with high compaction intensity; if the organic silica particle complex without pores, then the organic matter is organic matter with high compaction intensity.

[0217] In this example, based on the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot, it was observed that: organic matter between mineral particles and raspberry-shaped pyrite intercrystalline porous organic matter in the target shale gas sweet spot; among them, the organic matter between mineral particles is a mass of pure organic matter without pores (such as Figure 4b ) and non-porous strip-shaped pure organic matter (such as Figure 4c As shown) and impregnated non-porous organic clay complexes (such as Figure 4d 、 Figure 4e Among them, the organic matter filling the intercrystalline pores of raspberry pyrite is pure organic matter without pores (such as Figure 4f Specifically:

[0218] In this example, the target shale gas sweet spot rock development is: (1) the organic matter between mineral particles is agglomerated pure organic matter without pores (such as Figure 4d(2) The organic matter between mineral particles is pure organic matter in the form of strips without pores (as shown in Figure 4c (3) The organic matter between mineral particles is a non-porous organic clay complex (such as Figure 4d 、 Figure 4e (5) The organic matter in the intercrystalline pores of raspberry pyrite is pure organic matter without pores (such as Figure 4f This organic matter is independent of the intensity of compaction.

[0219] In this embodiment, the organic matter developed in the target shale gas sweet spot section that is not related to the intensity of compaction specifically includes some organic matter between mineral particles and organic matter in intercrystalline pores of raspberry pyrite. Its specific occurrence state is described as follows. This part of the organic matter between mineral particles is pure organic matter without pores, and some is stored in agglomerates (such as Figure 4d As shown), some exist in strips (as Figure 4c The intercrystalline organic matter of raspberry pyrite is pure organic matter with no pores (such as Figure 4f shown).

[0220] In this embodiment, the organic matter with high compaction strength in the target shale gas sweet spot is part of the organic matter between mineral particles, and its specific occurrence state is as follows. This part of the organic matter between mineral particles is an organic clay complex with no pores and is distributed in the mineral particles in a disseminated manner (such as Figure 4d 、 Figure 4e As shown), it is essentially a pyroasphalt clay complex solid asphalt petroleum clay complex with high compaction strength.

[0221] Methods for evaluating reservoir quality in shale gas sweet spots include:

[0222] 1. Obtain a rock sample from the shale gas sweet spot section D in Area A as the target shale gas sweet spot rock sample. Use the target shale gas sweet spot rock sample to prepare an argon ion polished wafer of the target shale gas sweet spot rock. Select an area on the polished surface of the argon ion polished wafer of the target shale gas sweet spot rock with a length and width no greater than 400 μm. Collect a MAPS rock image data volume with a resolution of 4 nm.

[0223] Here, the MAPS rock image data volume obtained in step 3 of the shale gas sweet spot compaction strength evaluation method of Example 4 can be directly used.

[0224] 2. Based on the collected MAPS rock image data volume, determine the organic pores and organic matter occurrence status of the target shale gas sweet spot rock samples, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the target shale gas sweet spot rock samples; among them, mesoporous organic matter includes pure organic matter and organic clay complexes with rich mesoporous organic pores distributed outside the silica shell, as well as organic matter with rich mesoporous organic pores in pure organic matter and organic clay complexes distributed outside the silica shell.

[0225] In this embodiment, the content of mesoporous organic matter and the non-porous organic clay complex in the target shale gas sweet spot rock sample is 0%, and the content of the non-porous organic clay complex is 100%.

[0226] 3. Evaluate the reservoir quality of the target shale gas sweet spot based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot;

[0227] Among them, when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot section presents the characteristics of medium compaction intensity, and the target shale gas sweet spot section is a high-quality reservoir; when the content of mesoporous organic matter in the mesoporous organic matter and the non-porous organic clay complexes in the target shale gas sweet spot section rock sample is less than 95% and greater than or equal to 50% and the content of the non-porous organic clay complex is greater than 5% and less than or equal to 50%, the target shale gas sweet spot section presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot section is a general reservoir. layer; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complex is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity to medium compaction intensity, and the target shale gas sweet spot is a poor reservoir; when the content of mesoporous organic matter and mesoporous organic matter in the non-porous organic clay complex of the target shale gas sweet spot rock sample is less than 5% and the content of non-porous organic clay complex is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity, and the target shale gas sweet spot is a non-reservoir.

[0228] In this embodiment, the content of mesoporous organic matter in the mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot section is 0%, and the content of non-porous organic clay complexes is 100%. Therefore, the target shale gas sweet spot section has a high compaction strength characteristic and is a non-reservoir.

[0229] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for evaluating the compaction strength of a shale gas sweet spot, the method comprising: Obtain rock samples from the target shale gas sweet spot; Determine the organic pores and organic matter occurrence status of rock samples in the target shale gas sweet spot; Determine the compaction intensity of organic matter in the rock samples of the target shale gas sweet spot based on the organic pores and organic matter occurrence state of the rock samples; Among them, the compaction intensity of organic matter with rich macropore organic pores distributed in the silica shell is low compaction intensity; the pure organic matter with rich macropore organic pores distributed outside the silica shell is insensitive to the compaction intensity; the compaction intensity of pure organic matter and organic clay complex with rich macropore organic pores and mesopore organic pores distributed outside the silica shell is medium compaction intensity; the compaction intensity of pure organic matter and organic clay complex with rich mesopore organic pores is medium compaction intensity; pure organic matter without pores is insensitive to the compaction intensity; the compaction intensity of organic clay complex without pores is high compaction intensity; the compaction intensity of organic silicon particle complex without pores is high compaction intensity.

2. The method according to claim 1, wherein The organic matter distributed in the silicon shell and developing macroporous organic pores also has the following occurrence characteristics: it is an organic silicon particle complex and / or a filling in the silicon shell cavity of a complete silicon shell; and / or The pure organic matter with rich macroporous organic pores distributed outside the silica shell also has the following occurrence characteristics: it exists in agglomerates between mineral particles; and / or The pure organic matter and organic clay complex distributed outside the silica shell and rich in macroporous organic pores and mesoporous organic pores also has the following occurrence characteristics: exists in agglomerates between rock skeleton particles; and / or The complex of pure organic matter and organic clay particles rich in mesoporous organic pores also has the following occurrence characteristics: exists in the form of clumps between rock skeleton particles, exists in the form of strips between rock skeleton particles, or is a filling of berry-like pyrite intercrystalline pores, or is a filling of the silica shell cavity of a defective silica shell; and / or Pure organic matter without pores may also have the following occurrence characteristics: it exists in the form of agglomerates between mineral particles, or exists in the form of stripes between mineral particles, or exists as berry-like intercrystalline pore fillings of pyrite; and / or The non-porous organoclay complex also has the following occurrence characteristics: it exists between mineral particles in the form of agglomerates, or in the form of strips, or in the form of dissemination; and / or The non-porous organosilicon particle composite also has the following occurrence characteristics: it is a filling in the silicon shell cavity of the incomplete silicon shell.

3. The method according to claim 1, wherein Determine the organic pores and organic matter occurrence status of rock samples in the target shale gas sweet spot, including: Using the rock sample of the target shale gas sweet spot section to make the argon ion polished slice of the target shale gas sweet spot section rock; Collect MAPS rock image data volumes of argon ion polished slices of target shale gas sweet spot rock; Based on the MAPS rock image data volume of the argon ion polished slices of the target shale gas sweet spot section rock, the organic pores and organic matter occurrence status of the target shale gas sweet spot section rock samples are determined; Preferably, collecting a MAPS rock image data volume of an argon ion polished sheet of rock in the target shale gas sweet spot segment includes: selecting an area with a length and a width not exceeding 400 μm on a polished surface of the argon ion polished sheet of rock in the target shale gas sweet spot segment, and collecting the MAPS rock image data volume; Preferably, the argon ion polished slice of the target shale gas sweet spot rock has a length of 0.8-2 cm, a width of 0.8-2 cm, and a thickness of 0.3-0.8 cm.

4. The method according to claim 3, wherein: The resolution of the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock is 1-10nm.

5. The method according to claim 3, wherein The top and bottom surfaces of the argon ion polished slice of the target shale gas sweet spot rock are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state; and / or During the process of collecting the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock, the top surface of the argon ion polished slice of the target shale gas sweet spot section rock is located above the field of view, and the bottom surface of the argon ion polished slice of the target shale gas sweet spot section rock is located below the field of view.

6. A method for evaluating the reservoir quality of a shale gas sweet spot, wherein: The method includes: Obtain rock samples from the target shale gas sweet spot; Determine the occurrence state of organic pores and organic matter in rock samples of the target shale gas sweet spot, and then determine the content of mesoporous organic matter and the content of non-porous organic clay complexes in the mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot; wherein, mesoporous organic matter includes pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in mesoporous organic pores, as well as pure organic matter and organic clay complexes that are distributed outside the silica shell and are rich in macroporous organic pores and mesoporous organic pores; The reservoir quality of the target shale gas sweet spot is evaluated based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot.

7. The method according to claim 6, wherein: Based on the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot, the reservoir quality of the target shale gas sweet spot is evaluated in the following ways: When the content of mesoporous organic matter in the rock sample of the target shale gas sweet spot and the non-porous organic clay complex is ≥95% and the content of the non-porous organic clay complex is ≤5%, the target shale gas sweet spot presents the characteristics of medium compaction intensity and is a high-quality reservoir. When the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot is less than 95% and greater than or equal to 50%, and the content of non-porous organic clay complexes is greater than 5% and less than or equal to 50%, the target shale gas sweet spot presents the characteristics of medium to high compaction intensity, and the target shale gas sweet spot is a general reservoir; When the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot is less than 50% and greater than or equal to 5%, and the content of non-porous organic clay complexes is greater than 50% and less than or equal to 95%, the target shale gas sweet spot presents a high compaction intensity to a medium compaction intensity characteristic, and the target shale gas sweet spot is a poor reservoir; When the content of mesoporous organic matter and non-porous organic clay complexes in the rock sample of the target shale gas sweet spot is less than 5% and the content of non-porous organic clay complexes is greater than 95%, the target shale gas sweet spot presents the characteristics of high compaction intensity and is a non-reservoir.

8. The method according to claim 6, wherein: Determine the occurrence state of organic pores and organic matter in the rock samples of the target shale gas sweet spot, and then determine the content of mesoporous organic matter and non-porous organic clay complexes in the rock samples of the target shale gas sweet spot, including: Using the rock sample of the target shale gas sweet spot section to make the argon ion polished slice of the target shale gas sweet spot section rock; Collect MAPS rock image data volumes of argon ion polished slices of target shale gas sweet spot rock; Based on the MAPS rock image data volume of the argon ion polished slices of the target shale gas sweet spot section rock, the organic pores and organic matter occurrence state of the target shale gas sweet spot section rock samples are determined, and then the content of mesoporous organic matter and non-porous organic clay complexes in the target shale gas sweet spot section rock samples are calculated; Preferably, the argon ion polished slice of the target shale gas sweet spot rock has a length of 0.8-2 cm, a width of 0.8-2 cm, and a thickness of 0.3-0.8 cm; Preferably, collecting the MAPS rock image data volume of the argon ion polished sheet of the target shale gas sweet spot rock includes: selecting an area with a length and width not exceeding 400 μm on the polished surface of the argon ion polished sheet of the target shale gas sweet spot rock, and collecting the MAPS rock image data volume.

9. The method according to claim 8, wherein The resolution of the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock is 1-10nm.

10. The method according to claim 8, wherein The top and bottom surfaces of the argon ion polished slice of the target shale gas sweet spot rock are parallel to the top and bottom surfaces of the target shale gas sweet spot rock sample in the underground state; and / or During the process of collecting the MAPS rock image data volume of the argon ion polished slice of the target shale gas sweet spot section rock, the top surface of the argon ion polished slice of the target shale gas sweet spot section rock is located above the field of view, and the bottom surface of the argon ion polished slice of the target shale gas sweet spot section rock is located below the field of view.

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