A rock slice-based solid bitumen identification method

Abstract

The present application provides a kind of solid pitch identification method based on rock slice, specifically comprising: grinding rock sample into rock slice, under polarizing microscope, the occurrence and optical property characteristics of solid pitch are observed using transmitted light, organic microcomponent and metal mineral interference are discharged, under polarizing microscope, the optical property characteristics of solid pitch are observed using reflected light, organic microcomponent and metal mineral interference are excluded, laser raman characteristics of solid pitch are tested, dark mineral interference is excluded, optical property characteristics and laser raman characteristics are comprehensively analyzed, and solid pitch is qualitatively and quantitatively identified.The method provided by the present application comprehensively considers the components most likely to be confused with solid pitch in rock, and is more in line with geological actual conditions;Rock slice preparation belongs to the most conventional and basic sample preparation method in the field of petroleum geology, which is simpler, more convenient and lower in cost;The identification method is simple, strong in operability and strong in universality;The qualitative and quantitative identification method has high accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of geology and petroleum geology research, and in particular to a solid asphalt identification method based on rock slices. Background Art

[0002] Solid asphalt generally refers to the solid residues of the thermal evolution of petroleum in rocks. That is, during the burial or migration process of the oil reservoir, the organic matter in the reservoir undergoes long-term cracking, degradation and other component differentiation, resulting in physical and chemical phase changes, and the solid carbon-rich products are gradually precipitated and enriched in the rock.

[0003] Solid asphalt has been discovered in reservoirs and source rocks throughout major oil and gas basins worldwide. For example, large quantities of solid asphalt have been found in the Sinian-Jurassic strata of the Sichuan Basin, the Ordovician and Silurian strata of the Tarim Basin, and the Triassic-Jurassic strata of the Junggar Basin. Solid asphalt in rocks contains crucial information about the formation and evolution of oil and gas, providing direct evidence of their passage and a crucial marker for identifying oil and gas reservoirs. Therefore, the identification of solid asphalt in rocks is crucial for studying the formation, evolution, and accumulation of oil and gas.

[0004] The traditional method for identifying solid asphalt in the petroleum geology industry is to prepare a rock sample into a slide, place it under a reflective microscope, and observe its reflected light characteristics. It is generally believed that there are two identifying features of solid asphalt under a reflective microscope: ① Shape, which can be round, oval, or irregular, depending on the space it fills; and ② Color, which can appear grayish black to grayish white under reflected white light. Since solid asphalt is a highly evolved organic matter, it generally does not fluoresce. The preparation of rock slides is somewhat destructive to the rock sample. The specific process is as follows: First, the rock sample is crushed. Epoxy resin and a curing agent or other non-fluorescent adhesive are selected. The sample and epoxy resin are placed in a circular mold in proportion and stirred evenly. After slightly curing, epoxy resin is added to the sample to a specified height. After curing for 24 hours, the sample is polished to a smooth surface without protrusions or indentations, following a process of fine grinding, fine grinding, fine polishing, and fine polishing.

[0005] However, in practical applications, the reflected light identification method based on rock slices has obvious limitations. On the one hand, rock components are complex, and substances that are easily confused with solid bitumen include, in addition to organic microscopic components, certain inorganic metal minerals (represented by pyrite) and dark minerals (represented by biotite). Although single reflected light observation has advantages in distinguishing solid bitumen from organic microscopic components, it cannot distinguish similar inorganic minerals. Moreover, the identification method that only provides qualitative but not quantitative analysis is not accurate enough. On the other hand, the preparation of rock slices is somewhat destructive to rock samples and does not constitute "in situ" observation and identification. In short, traditional solid bitumen identification methods (sample preparation and observation methods) have obvious limitations and cannot meet production needs. Many samples containing solid bitumen are overlooked in actual production, resulting in the loss of important oil and gas reservoir evidence. Therefore, how to establish a universal, practical, and effective solid bitumen identification method has become a technical challenge that needs to be solved urgently. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a solid asphalt identification method based on rock slices. The rock sample is prepared into an ordinary rock slice with a thickness of 30μ. First, the occurrence and optical characteristics of the solid asphalt are observed using a polarizing microscope using transmitted light (single polarized light, orthogonal polarized light), and the optical characteristics of the solid asphalt are observed using reflected light (white light, single polarized light, orthogonal polarized light), eliminating the interference of organic microscopic components and metal minerals. Then, the laser Raman characteristics of the solid asphalt are tested to eliminate the interference of dark minerals. Finally, the optical characteristics and laser Raman characteristics are comprehensively analyzed to qualitatively and quantitatively identify the solid asphalt, solving the current problem of solid asphalt identification. The method is simple and has strong operability and scalability.

[0007] In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0008] A method for identifying solid asphalt based on rock slices specifically comprises the following steps: S01. Grinding a rock sample into a rock slice. S02. Observing the occurrence and optical characteristics of the solid asphalt using transmitted light under a polarizing microscope to eliminate interference from organic microscopic components and metallic minerals. S03. Observing the optical characteristics of the solid asphalt using reflected light under a polarizing microscope to eliminate interference from organic microscopic components and metallic minerals. S04. Testing the laser Raman characteristics of the solid asphalt to eliminate interference from dark minerals. S05. Comprehensively analyzing the optical characteristics and laser Raman characteristics to qualitatively and quantitatively identify the solid asphalt.

[0009] According to the present invention's rock thin section-based solid asphalt identification method, rock samples are prepared into common rock thin sections with a thickness of 30μ. The occurrence and optical characteristics of the solid asphalt are first observed using a polarizing microscope using transmitted light (single polarization and crossed polarization), and the optical characteristics of the solid asphalt are observed using reflected light (white light, single polarization, and crossed polarization), eliminating interference from organic microscopic components and metallic minerals. The solid asphalt is then tested for laser Raman characteristics, eliminating interference from dark minerals. Finally, the optical and laser Raman characteristics are comprehensively analyzed to qualitatively and quantitatively identify the solid asphalt. This method is simple, highly operational, and scalable, resolving the current challenges in solid asphalt identification. Compared to traditional methods, the present invention comprehensively considers the components in the rock most likely to be confused with solid asphalt, including organic microscopic components, metallic minerals, and dark minerals, and is more consistent with geological reality. Furthermore, the rock thin section preparation method is one of the most common and fundamental sample preparation methods in the field of petroleum geology. Compared with rock optical section preparation, it is simpler, more convenient, and less expensive, and offers higher accuracy in both qualitative and quantitative identification.

[0010] The above technical solution can be further improved as described below.

[0011] According to the rock slice-based solid asphalt identification method of the present invention, in a preferred embodiment, in step S02, the occurrence and optical characteristics of the solid asphalt are observed under single polarized light and orthogonal polarized light illumination conditions of transmitted light, respectively.

[0012] The occurrence characteristics of solid asphalt under single-polarized and crossed-polarized transmitted light illumination are: it typically has no fixed shape. In thin sections, it often appears as strips, veins, lines, networks, or beads, filling pores or cracks. Its morphology can vary depending on the pore shape. Pores include but are not limited to intergranular pores, intercrystalline pores, intragranular pores, intergranular solution pores, intercrystalline solution pores, and intragranular solution pores. Cracks include but are not limited to tectonic fractures, dissolution fractures, and diagenetic fractures. In addition, contamination may occur at the contact points between solid asphalt and surrounding minerals. The optical characteristics of solid asphalt under single-polarized and crossed-polarized transmitted light illumination are: it is typically tan to black and opaque, and desiccation and shrinkage cracks may be visible. The occurrence and optical characteristics of solid asphalt under single-polarized and crossed-polarized transmitted light illumination are clearly different from those of organic microscopic components and metallic minerals. Based on these differences in characteristics, interference from organic microscopic components and metallic minerals can be ruled out.

[0013] Furthermore, in a preferred embodiment, step S02 specifically includes the following sub-steps: S021, using a transmitted light path for illumination, and setting a polarizer between the light source and the sample, and the incident light obtains linearly polarized light through the polarizer; S022, using a transmitted light path for illumination, and adding a polarizer between the light source and the sample, and adding an analyzer between the objective lens and the eyepiece, and the vibration directions of the polarizer and the analyzer are perpendicular to each other, and the linearly polarized light formed by the polarizer cannot pass through the analyzer at all.

[0014] Through the above sub-step S021, the optical characteristics of solid asphalt can be observed under single polarized transmitted light conditions, and through the above sub-step S022, the optical characteristics of solid asphalt can be observed under cross polarized transmitted light conditions.

[0015] Furthermore, in a preferred embodiment, in step S03, the optical characteristics of the solid asphalt are observed under the conditions of reflected white light, single polarized light, and orthogonal polarized light illumination, respectively.

[0016] The optical characteristics of solid asphalt under white reflected light illumination are: typically off-white to gray-black, but with low reflected light intensity, opacity, a matte surface, and no metallic luster. The optical characteristics of solid asphalt under single-polarized reflected light illumination are: typically gray to gray-black, opaque, without a metallic luster, and a matte surface. The surface roughness increases with color, and there are no obvious structural features. Inhomogeneity may exist, meaning that darker solid asphalt may exhibit anisotropy when the stage is rotated 360°. However, if anisotropy exists, the brightness difference caused by changes in light and dark is not significant. The optical characteristics of solid asphalt under crossed polarized reflected light illumination are: typically grayish black to dark brown to black, opaque, without metallic luster, and with a rough surface. The surface roughness gradually increases with color deepening, and there are no obvious structural features. Inhomogeneity may exist, meaning that when the stage is rotated 360°, darker solid asphalt may exhibit anisotropy. However, if anisotropy exists, the brightness difference caused by the changes in light and dark is not significant. The optical characteristics of solid asphalt under white light, single polarized light, and crossed polarized reflected light illumination are clearly different from those of organic microscopic components and metallic minerals. Based on these differences in characteristics, interference from organic microscopic components and metallic minerals can be ruled out.

[0017] Furthermore, in a preferred embodiment, step S03 specifically includes the following sub-steps: S031, using a reflected light path for illumination, the incident light directly irradiates the sample surface, S032, using a reflected light path for illumination, and setting a polarizer between the objective lens and the eyepiece, the incident light is reflected by the sample, and then linearly polarized light is obtained through the polarizer, S033, using a reflected light path for illumination, and adding a polarizer between the light source and the sample, and adding an analyzer between the objective lens and the eyepiece, and the vibration directions of the polarizer and the analyzer are perpendicular to each other, and the linearly polarized light formed by the polarizer cannot pass through the analyzer at all.

[0018] Through the above-mentioned sub-step S031, the optical characteristics of solid asphalt can be observed under white light reflection light conditions, through the above-mentioned sub-step S032, the optical characteristics of solid asphalt can be observed under single polarized light reflection light conditions, and through the above-mentioned sub-step S033, the optical characteristics of solid asphalt can be observed under cross-polarized light reflection light conditions.

[0019] Furthermore, in a preferred embodiment, step S04 specifically includes the following sub-steps: S041, collecting the laser Raman spectrum of the solid asphalt, S042, analyzing the Raman spectrum characteristics of the solid asphalt, determining the composition of the solid asphalt, and eliminating the interference of dark minerals.

[0020] Through the above sub-steps, the interference of dark minerals can be eliminated simply and effectively.

[0021] Furthermore, in a preferred embodiment, in sub-step S041, Raman spectroscopy is performed on the solid asphalt in the rock slice to obtain an original Raman spectrum of the solid asphalt, and then the background of the original Raman spectrum is subtracted to obtain a Raman spectrum of the solid asphalt.

[0022] The Raman spectrum of solid asphalt obtained by the above method is simple, convenient and highly accurate.

[0023] Furthermore, in a preferred embodiment, in sub-step S042, the laser Raman characteristics of solid asphalt belong to typical organic Raman spectral characteristics, and dark minerals belong to inorganic Raman spectral characteristics, and the interference of dark minerals is eliminated based on the difference in characteristics.

[0024] The above specific steps can quickly and accurately eliminate the interference of dark minerals.

[0025] Furthermore, in a preferred embodiment, in step S05, based on the occurrence and optical characteristics of solid asphalt under transmitted light illumination conditions and the optical characteristics under reflected light illumination conditions, interference from organic microscopic components and metal minerals is eliminated, and then based on the laser Raman characteristics of solid asphalt, interference from dark minerals is eliminated, and comprehensive analysis is performed to qualitatively and quantitatively identify solid asphalt.

[0026] Through the comprehensive analysis of the above step S05, the accuracy of solid asphalt identification can be greatly improved.

[0027] Specifically, in a preferred embodiment, the occurrence of solid asphalt includes morphology, location at the time of formation and relationship with surrounding minerals, and the optical characteristics of solid asphalt include color, transparency, structure and anisotropy.

[0028] A comprehensive analysis of the above-mentioned contents related to the occurrence and optical characteristics of solid asphalt can also ensure that the accuracy of solid asphalt identification is improved in all aspects.

[0029] Compared with the existing technology, the advantages of the present invention are: 1) it comprehensively considers the components in the rock that are most likely to be confused with solid asphalt, including organic microscopic components, metallic minerals and dark minerals, which is more in line with the actual geological situation; 2) rock thin section preparation is the most conventional and basic sample preparation method in the field of petroleum geology. Compared with rock optical section preparation, it is simpler, more convenient and less costly; 3) the identification method is simple, highly operational and universal; 4) the qualitative and quantitative identification method has a higher accuracy rate than the traditional method that relies solely on optical characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0031] Figure 1 The process of the solid asphalt identification method according to an embodiment of the present invention is schematically shown;

[0032] Figure 2 The process of step S02 in an embodiment of the present invention is schematically shown;

[0033] Figure 3 The process of step S03 in the embodiment of the present invention is schematically shown;

[0034] Figure 4 Schematic diagram showing the characteristics of solid asphalt in rock slices in step S02 of an embodiment of the present invention;

[0035] Figure 5 Schematic diagram showing the characteristics of solid asphalt in rock slices in step S03 of an embodiment of the present invention;

[0036] Figure 6 The laser Raman spectrum of solid asphalt according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereby.

[0038] Figure 1 The flowchart of the solid asphalt identification method according to an embodiment of the present invention is schematically shown. Figure 2 The process of step S02 in the embodiment of the present invention is schematically shown. Figure 3 The process of step S03 in the embodiment of the present invention is schematically shown. Figure 4 The diagram schematically shows the characteristics of solid asphalt in the rock slice in step S02 of an embodiment of the present invention. Figure 5 The diagram schematically shows the characteristics of solid asphalt in the rock slice in step S03 of an embodiment of the present invention. Figure 6 The laser Raman spectrum of solid asphalt according to an embodiment of the present invention is schematically shown.

[0039] like Figures 1 to 3 A rock sample is selected and the solid asphalt identification method according to an embodiment of the present invention is used to identify the solid asphalt therein. The specific steps are as follows:

[0040] S01. Grind the rock sample into a common rock slice with a thickness of 30μ;

[0041] Ordinary rock thin sections are made according to the steps of sampling - gluing - surface grinding (coarse grinding - medium grinding - fine grinding - fine grinding) - sticking - grinding (coarse grinding - fine grinding - fine grinding) - cover slicing. The standard thickness is 30μ. For the specific production process, please refer to the industry standard SY-T 5913-2004 "Rock Slicing Method".

[0042] S02. Under a polarizing microscope, use single polarized light and orthogonal polarized transmitted light to observe the occurrence and optical characteristics of solid asphalt, eliminating interference from organic microscopic components and metal minerals. The specific process of this step is as follows: Figure 2 As shown;

[0043] The occurrence characteristics of solid asphalt under single-polarized and cross-polarized transmitted light illumination are: it generally has no fixed shape. In thin sections, it often appears as strips, veins, lines, networks, or beads, filling pores or cracks. Its morphology can vary depending on the pore structure. Pores include but are not limited to intergranular pores, intercrystalline pores, intragranular pores, intergranular solution pores, intercrystalline solution pores, and intragranular solution pores. Cracks include but are not limited to tectonic fractures, dissolution fractures, and diagenetic fractures. In addition, contamination may occur at the contact points between solid asphalt and surrounding minerals. In contrast, the occurrence and optical characteristics of organic microscopic components under single-polarized and orthogonal polarized transmitted light illumination conditions are as follows: vitrinite, as a degradation body or gel of higher plants, is usually blocky or fragmentary, homogeneous vitrinite may appear as strips and lenses of varying widths, fragmentary vitrinite and vitrinite component fragments with a particle size of less than 10μm are mostly granular, irregular, and occasionally angular; graptolites, as living organisms, are usually fragmented and lens-shaped, and the organic microscopic components have clear boundaries, no impregnation at the contact with surrounding minerals, and are dark and opaque.

[0044] The optical characteristics of solid asphalt under single polarized and crossed polarized transmitted light are: typically tan to black, opaque, and with visible shrinkage cracks. In contrast, the occurrence and optical characteristics of metallic minerals under single polarized and crossed polarized transmitted light are: as crystals, they have euhedral structures, regular crystalline shapes, dark colors, and are opaque.

[0045] Based on the occurrence and optical characteristics of solid asphalt under single polarized light and orthogonal polarized transmitted light illumination conditions, there are obvious differences between it and organic microscopic components and metal minerals, and the interference of organic microscopic components and metal minerals can be ruled out. Figure 4 shown.

[0046] S03. Under a polarizing microscope, use white light, single polarized light, and orthogonal polarized reflected light to observe the optical characteristics of solid asphalt, eliminating interference from organic microscopic components and metal minerals. The specific process of this step is as follows: Figure 3 As shown;

[0047] The optical characteristics of solid asphalt under white light reflected light illumination conditions are: usually grayish white to grayish black, but the reflected light intensity is not high, it is opaque, the surface is not smooth, and there is no metallic luster.

[0048] The optical characteristics of solid asphalt under single polarized reflected light illumination are: usually gray to gray-black, opaque, without metallic luster, and with a rough surface. As the color deepens, the surface roughness gradually increases. There are no obvious structural features, and there may be heterogeneity. That is, when the stage is rotated 360°, the darker solid asphalt may be anisotropic. However, if anisotropic characteristics exist, the brightness difference caused by the light and dark changes is not large.

[0049] The optical characteristics of solid asphalt under orthogonal polarized reflected light illumination are: usually gray-black-dark brown-black, opaque, without metallic luster, and with a rough surface. As the color deepens, the surface roughness gradually increases. There are no obvious structural features and there may be heterogeneity. That is, when the stage is rotated 360°, the darker solid asphalt may be anisotropic. However, if anisotropic characteristics exist, the brightness difference caused by the light and dark changes is not large.

[0050] In contrast, the optical characteristics of organic microscopic components under white light, single polarized light and orthogonal polarized reflected light illumination conditions are as follows: the surfaces of microscopic components such as vitrinite are relatively smooth. As transformants of higher plants, they usually retain the special morphology and structure of plant tissues. Homogeneous vitrinite is highly homogeneous, uniform and pure; graptolites usually have fibrous, spindle-shaped, and segmented structural characteristics, and have high reflected light intensity. When the stage is rotated 360°, non-granular graptolites will show obvious changes in light and dark, and the high brightness difference indicates that they have strong anisotropic optical characteristics.

[0051] In contrast, the optical characteristics of metallic minerals under white light, single polarized light and orthogonal polarized reflected light illumination conditions are: usually with yellow and brown reflections, showing a distinct metallic luster.

[0052] Based on the occurrence and optical characteristics of solid asphalt under white light, single polarized light and orthogonal polarized reflected light illumination conditions, there are obvious differences between it and organic microscopic components and metal minerals, and the interference of organic microscopic components and metal minerals can be ruled out. Figure 5 shown.

[0053] S04. Test the laser Raman characteristics of solid asphalt to eliminate the interference of dark minerals. The laser Raman spectrum of solid asphalt is as follows: Figure 6 As shown;

[0054] The acquisition steps are: perform Raman spectroscopy analysis on the solid asphalt in the rock slice to obtain the original Raman spectrum of the solid asphalt, and then subtract the background of the original Raman spectrum to obtain the Raman spectrum of the solid asphalt.

[0055] The characteristics of the laser Raman spectrum of solid asphalt and the analysis of the composition of solid asphalt are as follows: in the Raman spectrum, the horizontal axis is the Raman shift, and its value range is 500~2500cm-1, and the vertical axis is the intensity, and the unit is dimensionless; the Raman spectrum of solid asphalt has two characteristic peaks in the frequency range of 1000cm-1~2000cm-1, and their positions are between 1580cm-1~1600cm-1 and 1350cm-1~1380cm-1 respectively. The former belongs to the doubly degenerate E2g vibration mode of the graphite crystal symmetry structure, reflecting the carbon-carbon vibration on the aromatic configuration plane in the molecular structure, called the G peak; the latter belongs to the vibration mode of the irregular hexagonal lattice structure of amorphous graphite, which is related to the defects between the molecular structure units, and is called the D peak.

[0056] In contrast, dark minerals are inorganic substances and have the laser Raman characteristics of minerals, which are significantly different from the laser Raman characteristics of solid asphalt.

[0057] The laser Raman characteristics of solid asphalt are significantly different from those of dark minerals, and the interference of dark minerals can be eliminated.

[0058] S05. Comprehensively analyze optical characteristics and laser Raman characteristics to qualitatively and quantitatively identify solid asphalt.

[0059] In summary, based on the occurrence and optical characteristics of solid asphalt under single polarized and orthogonal polarized transmitted light illumination conditions, and the optical characteristics under white light, single polarized and orthogonal polarized reflected light illumination conditions, the interference of organic microscopic components and metal minerals is eliminated, and then based on the laser Raman characteristics of solid asphalt, the interference of dark minerals is eliminated, and a comprehensive analysis is performed to qualitatively and quantitatively identify solid asphalt.

[0060] According to the above embodiments, it can be seen that the solid asphalt identification method based on rock slices involved in the present invention comprehensively considers the components in the rock that are most likely to be confused with solid asphalt, including organic microscopic components, metal minerals and dark minerals, which is more in line with the actual geological situation; rock thin section preparation is the most conventional and basic sample preparation method in the field of petroleum geology, and is simpler, more convenient and less costly than rock optical section preparation; the identification method is simple, highly operational and universal; the qualitative and quantitative identification method has a high accuracy rate compared with the traditional method that relies solely on optical characteristics.

[0061] While the present invention has been described with reference to preferred embodiments, various modifications may be made and equivalent components may be substituted without departing from the scope of the present invention. In particular, the various technical features described in the various embodiments may be combined in any manner, provided no structural conflicts exist. The present invention is not limited to the specific embodiments disclosed herein, but encompasses all technical solutions within the scope of the claims.

Claims

1. A solid asphalt identification method based on rock slices, characterized in that: The specific steps include: S01, grinding the rock sample into rock slices; S02. Observe the occurrence and optical properties of solid asphalt using transmitted light under a polarizing microscope, eliminating interference from organic microscopic components and metallic minerals; S03. Observe the optical characteristics of solid asphalt using reflected light under a polarizing microscope, eliminating interference from organic microscopic components and metallic minerals; S04. Test the laser Raman characteristics of solid asphalt to eliminate interference from dark minerals; The step S04 specifically includes the following sub-steps: S041. Collecting a laser Raman spectrum of the solid asphalt, performing Raman spectral analysis on the solid asphalt in the rock slice to obtain an original Raman spectrum of the solid asphalt, and then subtracting the background of the original Raman spectrum to obtain a Raman spectrum of the solid asphalt; S042. Analyze the Raman spectral characteristics of the solid asphalt to determine the composition of the solid asphalt while eliminating interference from dark minerals. The laser Raman spectral characteristics of the solid asphalt are typical organic Raman spectral characteristics, while dark minerals are inorganic Raman spectral characteristics. Based on these differences in characteristics, interference from dark minerals is eliminated. S05. Comprehensively analyze optical characteristics and laser Raman characteristics to qualitatively and quantitatively identify solid asphalt.

2. The solid asphalt identification method based on rock slices according to claim 1 is characterized in that: In the step S02, the occurrence and optical characteristics of the solid asphalt are observed under the conditions of single polarized light and cross polarized light illumination of transmitted light respectively.

3. The solid asphalt identification method based on rock slices according to claim 2, characterized in that: The step S02 specifically includes the following sub-steps: S021. Use transmitted light for illumination and place a polarizer between the light source and the sample. The incident light passes through the polarizer to obtain linearly polarized light. S022. Use transmitted light for illumination, add a polarizer between the light source and the sample, and add an analyzer between the objective lens and the eyepiece. The vibration directions of the polarizer and analyzer are perpendicular to each other, and the linearly polarized light formed by the polarizer cannot pass through the analyzer at all.

4. The solid asphalt identification method based on rock slices according to any one of claims 1 to 3, characterized in that: In step S03, the optical characteristics of the solid asphalt are observed under the illumination conditions of reflected white light, single polarized light, and orthogonal polarized light.

5. The solid asphalt identification method based on rock slices according to claim 4 is characterized in that: The step S03 specifically includes the following sub-steps: S031, using reflected light path illumination, the incident light directly illuminates the sample surface; S032. Use reflected light path for illumination, and set a polarizer between the objective lens and the eyepiece. The incident light is reflected by the sample and then passes through the polarizer to obtain linearly polarized light. S033. Use reflected light path for illumination, add a polarizer between the light source and the sample, and add an analyzer between the objective lens and the eyepiece. The vibration directions of the polarizer and analyzer are perpendicular to each other, and the linearly polarized light formed by the polarizer cannot pass through the analyzer at all.

6. The solid asphalt identification method based on rock slices according to any one of claims 1 to 3, characterized in that: In step S05, based on the occurrence and optical characteristics of solid asphalt under transmitted light illumination conditions and the optical characteristics under reflected light illumination conditions, interference from organic microscopic components and metal minerals is eliminated. Then, based on the laser Raman characteristics of solid asphalt, interference from dark minerals is eliminated, and comprehensive analysis is performed to qualitatively and quantitatively identify solid asphalt.

7. The solid asphalt identification method based on rock slices according to any one of claims 1 to 3, characterized in that: The occurrence of the solid asphalt includes its morphology, location at the time of formation, and relationship with surrounding minerals; The optical characteristics of the solid asphalt include color, transparency, structure, anisotropy and other characteristics.

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