Method for determining causes of amorphous substances in rock

Abstract

The invention relates to the technical field of oil-gas exploration, in particular to a method for determining causes of amorphous substances in rocks, which introduces an element test and element three-end-member analysis method on the basis of the existing slice identification analysis method and scanning electron microscope analysis method, and uses the viewpoints of statistics and element geochemistry to determine the causes of amorphous substances in rocks. The quantitative analysis of the causes of the amorphous substances in the rock is realized, and the main control factors of rock diagenesis are further analyzed. Through the determination method, the influence degree of the deposition action and the volcanic action can be determined by analyzing the cause type of the amorphous substance in the rock, then the main control factor of the diagenesis is determined, and the problem that the cause of the amorphous substance in the rock is difficult to judge can be effectively solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas exploration, and in particular to a method for determining the genesis of amorphous substances in rocks. Background Art

[0002] Amorphous substances are important components of rocks, including amorphous organic matter and amorphous inorganic matter. Common amorphous organic matter in rocks includes kerogen, asphalt, etc., while common amorphous inorganic matter includes volcanic glass, opal, diaspore, limonite, etc. Different types of amorphous substances reflect different rock genesis. According to the theory of organic origin of oil and gas, biopolymers in sediments undergo separation, polymerization, and polycondensation under biochemical and chemical effects, and can form geological macromolecules-kerogen under diagenesis. Kerogen can form oil and gas resources after pyrolysis and cracking, and soluble organic matter-asphalt will be formed at the same time. It can be seen that the content of amorphous kerogen and asphalt is closely related to the formation of oil and gas. Similarly, volcanic glass in amorphous inorganic matter in rocks is a glassy structure formed by the rapid condensation of lava from volcanic eruptions without time to crystallize, and its content is closely related to volcanic action.

[0003] The Permian strata are one of the important strata for natural gas exploration in the Sichuan Basin. Most of the strata in this stratum are marine-continental transitional sedimentary systems. Its natural gas resources include both conventional natural gas and unconventional natural gas (shale gas and coalbed methane), as well as both sedimentary rock reservoirs and volcanic rock reservoirs. Among them, the shale gas resources of the Wujiaping Formation of the Permian in the Sichuan Basin exceed 6 trillion cubic meters. The Daye 1H well obtained a high-yield industrial gas flow in this stratum during testing, marking a major discovery of a new stratum in the Permian field in the Sichuan Basin.

[0004] Due to the Permian strata such as the Longtan Formation in eastern and southern Sichuan and the Wujiaping Formation in northern Sichuan, which are of different phases at the same time, the reservoir rocks have great vertical lithology variations, large changes in mineral composition, strong heterogeneity, and extremely complex rock components, containing both volcanic and sedimentary materials. This makes the analysis of their diagenesis and evolution mechanism extremely difficult, and also brings huge challenges to the evaluation of the natural gas exploration potential of this block and the next exploration work.

[0005] The existing analysis of amorphous rock materials mainly relies on polarizing microscopes and thin-section identification methods. Taking volcanic glass formed by volcanic action and asphalt (organic matter) formed by sedimentation as examples, the constituent particles are not crystallized or are isotropic, and both have no fixed body, so there is no obvious optical property under orthogonal polarization, but there is still a certain difference in the optical property and structure of the two under single polarization. Volcanic glass has certain optical properties under single polarization, and most of the color and texture change characteristics can be observed, but it is non-optical under orthogonal polarization. Asphalt is black in color, it is non-optical under single polarization and orthogonal polarization. Since amorphous volcanic glass will gradually transform into crystals during geological evolution and form a devitrified structure, the glassy structure often coexists with the devitrified structure, so the existence of volcanic glass can be identified based on different devitrified structures. Asphalt, because it is related to oil and gas migration, it is often distributed in rock pores, cracks and other structures, so it can be identified based on its spatial distribution characteristics. However, when volcanic glass and asphalt coexist and are present in high concentrations, especially when the two are interlaced or mixed, it is impossible to identify their contents through a polarizing microscope because both are optically non-optical. It is also impossible to analyze the extent of the impact of volcanic and sedimentary activities. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a method for determining the cause of amorphous substances in rocks. By analyzing the content of different types of amorphous substances in rocks, the influence of sedimentation and volcanism can be judged, and the main controlling factors of diagenesis can be clarified. Finally, the main geological effects affecting the formation of amorphous substances in rocks can be determined, and quantitative analysis of their causes can be achieved.

[0007] The present invention is achieved by adopting the following technical solutions: A method for determining the origin of amorphous material in rock comprises the following steps: Step S1. Select a rock sample and prepare the sample into rock powder, rock slices and sub-ion polished slices; Step S2. Perform X-ray diffraction analysis on the rock powder sample to determine the amorphous content therein; then perform carbon-sulfur analysis to determine the organic carbon content therein; when the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism; when the measured amorphous content is positively correlated with the organic carbon content or has no correlation, analyze and identify the rock slice in step S1 to determine whether organic matter and volcanic glass exist in the rock slice at the same time, and if so, proceed to step S3; Step S3. Using an electron probe method, a surface scanning test of carbon, silicon, aluminum, and iron is performed on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, to obtain an element surface scan and the corresponding percentages of carbon, silicon, aluminum, and iron, and determine whether the area contains carbon, silicon, aluminum, and iron at the same time; Step S4. Using a scanning electron microscope, the subionic polished sheet in step S1 is identified, and the region of amorphous material containing both volcanic glass and organic matter is determined based on the special morphological structure of the volcanic glass and organic matter; Step S5. Using an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4, obtain an element surface scan and its corresponding percentage of carbon, silicon, aluminum, and iron, and determine whether the area contains carbon, silicon, aluminum, and iron at the same time; Step S6. A triangular diagram is made with the percentage of carbon, silicon and aluminum + iron as the three end members, and the percentage of each element obtained in step S3 and step S5 is projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram; Step S7. Using the element distribution characteristics of the three-terminal element distribution diagram, identify the origin of the amorphous material in the rock.

[0008] In the step S7, the identification of the origin of the amorphous material in the rock specifically refers to: in the three-end member element distribution diagram, if the carbon end member has more scattered points than the silicon end member and the aluminum-iron end member, then it is judged that the amorphous material is mainly formed by sedimentation; if the silicon end member has more scattered points than the carbon end member and the aluminum-iron end member, then it is judged that the origin of the amorphous material is affected by both sedimentation and volcanism; if the aluminum-iron end member has more scattered points than the carbon end member and the silicon end member, then it is judged that the amorphous material is mainly formed by volcanism.

[0009] If there are many scattered points of silicon end members, combined with the element surface scans in step S3 and step S5, determine whether the spatial position distributions of carbon and silicon elements in the element surface scans are consistent. If the distribution positions of carbon and silicon elements are completely consistent, it is determined that the amorphous material is mainly caused by sedimentation. If the distribution positions of carbon and silicon elements are completely inconsistent, it is determined that the amorphous material is mainly caused by volcanism. If the distribution positions of carbon and silicon elements are not completely consistent, it is determined that the amorphous material is affected by both volcanism and sedimentation.

[0010] This also includes the identification of multiple areas of amorphous material containing both volcanic glass and organic matter.

[0011] The number of areas ultimately identified that contain both volcanic glass and amorphous organic matter is at least 10.

[0012] The analysis and identification of the rock slice in step S2 specifically refers to: using a polarizing microscope, under a single polarizing lens, to analyze and identify the rock slice.

[0013] The special morphological structures of the volcanic glass and organic matter in step S4 specifically refer to: the volcanic glass has a gel structure, and the organic matter has a biological structure.

[0014] In step S6, the triangular diagram is an equilateral triangular diagram.

[0015] The thickness of the rock slice is not more than 0.035 mm, and the thickness of the subionic polishing sheet is not more than 5 mm.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. Based on the existing thin section identification and analysis methods and scanning electron microscope analysis methods, the present invention introduces element testing and element three-terminal analysis methods, and uses the viewpoints of statistics and elemental geochemistry to achieve quantitative analysis of the origin of amorphous substances in rocks, and then analyzes the main controlling factors of rock diagenesis, solving the problem that a single thin section identification or scanning identification method cannot analyze the origin of amorphous substances, and can meet the research needs of reservoir rock diagenesis in marine-continental transitional phase and shallow marine phase sedimentary systems that are jointly affected by volcanic action and sedimentation.

[0017] 2. The present invention solves the technical problem that it is difficult to judge the content of organic amorphous substances and inorganic amorphous substances due to their similar optical properties and darker colors during the identification of rock thin sections through the method of elemental geochemistry, and overcomes the technical bottleneck that it is difficult to characterize the occurrence state of organic amorphous substances and inorganic amorphous substances due to their mixed existence.

[0018] 3. The present invention proposes to determine the main type of amorphous materials by means of X-ray diffraction and carbon-sulfur analysis, which effectively combines the two analysis methods of material composition and elemental composition, realizes the rapid identification of amorphous material types in rocks, and has important guiding significance for the study of rock diagenesis.

[0019] 4. The present invention proposes two microscopic positioning methods, namely, electron probe and subionic polishing scanning electron microscope. According to the special morphology and structure of volcanic glass and organic matter and whether the four elements of carbon, silicon, aluminum and iron are contained at the same time, the energy spectrum element surface scanning area can be effectively delineated. The resolution and accuracy of determining the analysis area are higher than those of a single rock thin section identification method. The invention effectively overcomes the difficulty in finding a suitable analysis area due to the limitation of the maximum resolution of a polarizing microscope. The invention is particularly suitable for analyzing rocks composed of micron and nanometer particles, such as shale and dense sandstone.

[0020] 5. The present invention uses statistical viewpoints and innovatively proposes a method for identifying the origin of amorphous substances in rocks by using the three-terminal distribution law of material elements. This method is mainly based on the scientific theory that the volcanic origin of amorphous substances in rocks is related to the enrichment of iron and aluminum elements, the sedimentary origin is related to the enrichment of carbon elements, and the enrichment of silicon elements is related to both volcanic and sedimentary effects. The origin of materials is analyzed by the source of elements. This analysis method is more reliable than a single analysis through rock mineral morphology, structure and content characteristics.

[0021] 6. The present invention realizes the quantitative characterization of the genesis of amorphous substances in rocks by establishing a three-end member analysis method. By clarifying the distribution law of three-end member elements, the influence of volcanic action and sedimentation can be analyzed, which provides a strong basis for analyzing the mechanism of rock diagenesis and provides strong data support for regional geological research on marine-continental transitional phase and shallow marine phase sedimentary systems.

[0022] 7. Based on the characteristics that organic silicon has Si-C bonds and inorganic silicon has Si-O bonds, the present invention uses the spatial distribution characteristics of elements for analysis, and can realize the analysis of the source and cause of silicon. By analyzing the source of silicon, the cause of amorphous substances in rocks can be further analyzed. This method is based on the theory of elemental geochemistry and can reflect the laws of geological action in depth. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 It is a schematic diagram of the distribution diagram of the three-terminal elements in the present invention. DETAILED DESCRIPTION

[0024] Example 1 As a basic embodiment of the present invention, the present invention includes a method for determining the origin of amorphous material in rock, comprising the following steps: Step S1. Select a rock sample, and make the sample into rock powder, rock slices and sublimation polished slices.

[0025] Step S2. Perform X-ray diffraction analysis on the rock powder sample to determine the amorphous content; then perform carbon-sulfur analysis to determine the organic carbon content. When the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism. When the measured amorphous content is positively correlated with the organic carbon content or has no correlation, analyze and identify the rock slice in step S1 to determine whether organic matter and volcanic glass exist in the rock slice at the same time. If so, proceed to step S3.

[0026] Step S3. Using an electron probe method, perform a surface scanning test of carbon, silicon, aluminum, and iron on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, obtain an element surface scan and the corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron, and determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0027] Step S4. Using a scanning electron microscope, the subionic polished wafer in step S1 is identified, and the region of amorphous material containing both volcanic glass and organic matter is determined based on the special morphological structure of the volcanic glass and organic matter.

[0028] Step S5. Use an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4 to obtain an element surface scan and its corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron to determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0029] Step S6. A triangular diagram is made with the percentage of carbon, silicon and aluminum + iron as the three end members, and the percentage of each element obtained in step S3 and step S5 is projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram.

[0030] Step S7. Using the element distribution characteristics of the three-terminal element distribution diagram, identify the origin of the amorphous material in the rock.

[0031] This embodiment uses the viewpoints of statistics and elemental geochemistry to achieve quantitative analysis of the causes of amorphous substances in rocks, and then assists in analyzing the main controlling factors of rock diagenesis, providing strong data support for exploration and development decision-making work such as reservoir geological evaluation.

[0032] Example 2 As a preferred embodiment of the present invention, the present invention includes a method for determining the origin of amorphous material in rock, comprising the following steps: Step S1. Select a rock sample, and make the sample into rock powder, rock slices and sublimation polished slices.

[0033] Step S2. Perform X-ray diffraction analysis on the rock powder sample to determine the amorphous content; then perform carbon-sulfur analysis to determine the organic carbon content. When the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism. When the measured amorphous content is positively correlated with the organic carbon content or has no correlation, analyze and identify the rock slice in step S1 to determine whether organic matter and volcanic glass exist in the rock slice at the same time. If so, proceed to step S3.

[0034] Step S3. Using an electron probe method, perform a surface scanning test of carbon, silicon, aluminum, and iron on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, obtain an element surface scan and the corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron, and determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0035] Step S4. Using a scanning electron microscope, identify the subionic polishing sheet produced in step S1, and determine the region of amorphous material containing both volcanic glass and organic matter based on the special morphological structure of volcanic glass and organic matter. Repeat the above steps to determine multiple regions of amorphous material containing both volcanic glass and organic matter. The number of regions of amorphous material containing both volcanic glass and organic matter determined at the end is at least 10.

[0036] Step S5. Use an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4 to obtain an element surface scan and its corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron to determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0037] Step S6. A triangular diagram is made with the percentage of carbon, silicon and aluminum + iron as the three end members, and the percentage of each element obtained in step S3 and step S5 is projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram.

[0038] Step S7. Use the element distribution characteristics of the three-end member element distribution diagram to identify the origin of the amorphous material in the rock. In the three-end member element distribution diagram, if the carbon end member has more scattered points than the silicon end member and the aluminum-iron end member, it is judged that the amorphous material is mainly formed by sedimentation; if the silicon end member has more scattered points than the carbon end member and the aluminum-iron end member, it is judged that the origin of the amorphous material is affected by both sedimentation and volcanism; if the aluminum-iron end member has more scattered points than the carbon end member and the silicon end member, it is judged that the amorphous material is mainly formed by volcanism.

[0039] Example 3 As another preferred embodiment of the present invention, the present invention includes a method for determining the origin of amorphous material in rock, comprising the following steps: S1. Select a rock sample and make the sample into rock powder, rock slices and subionic polishing slices respectively. The thickness of the rock slices is not more than 0.035 mm, and the thickness of the subionic polishing slice is not more than 5 mm.

[0040] Step S2. Perform X-ray diffraction analysis on the above rock powder sample to determine the amorphous content. Then perform carbon-sulfur analysis to determine the organic carbon content. When the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism. When the measured amorphous content is positively correlated with the organic carbon content or has no correlation, use a polarizing microscope to analyze and identify the rock slice in step S1 under a single polarizing lens to determine whether organic matter and volcanic glass exist in the rock slice at the same time. If so, proceed to step S3.

[0041] Step S3. Using an electron probe method, perform a surface scanning test of carbon, silicon, aluminum, and iron on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, obtain an element surface scan and the corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron, and determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0042] Step S4. Using a scanning electron microscope, the subionic polished sheet produced in step S1 is identified, and the region of amorphous material containing both volcanic glass and organic matter is determined based on the special morphological structure of the volcanic glass and organic matter.

[0043] Step S5. Use an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4 to obtain an element surface scan and its corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron to determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0044] Step S6. A triangular diagram is made with the percentage of carbon, silicon and aluminum + iron as the three end members, and the percentage of each element obtained in step S3 and step S5 is projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram.

[0045] Step S7. Use the element distribution characteristics of the three-end member element distribution diagram to identify the origin of the amorphous material in the rock. In the three-end member element distribution diagram, if the carbon end member has more scattered points than the silicon end member and the aluminum-iron end member, it is judged that the amorphous material is mainly formed by sedimentation; if the silicon end member has more scattered points than the carbon end member and the aluminum-iron end member, it is judged that the origin of the amorphous material is affected by both sedimentation and volcanism; if the aluminum-iron end member has more scattered points than the carbon end member and the silicon end member, it is judged that the amorphous material is mainly formed by volcanism.

[0046] Example 4 As the best embodiment of the present invention, the present invention includes a method for determining the origin of amorphous material in rock, comprising the following steps: Step S1. Select a rock sample and make the sample into rock powder, rock slices and subionic polished slices. The thickness of the rock slices should meet the technical requirements of "Rock Slice Preparation Method: SY / T 5913-2004", and in principle, the thickness should not exceed 0.035 mm; the thickness of the subionic polished slice should meet the technical requirements of "Scanning Electron Microscope Analysis Method for Rock Samples, SY / T 5162-2021", and in principle, the thickness should not exceed 5 mm.

[0047] Step S2. Perform X-ray diffraction analysis on the rock powder sample to determine the amorphous content; then perform carbon-sulfur analysis to determine the organic carbon content. When the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism.

[0048] When the measured amorphous content is positively correlated with the organic carbon content or has no correlation, the rock thin section identification method is used to analyze and identify the rock thin section in step S1. Specifically, the rock thin section is analyzed and identified using a polarizing microscope under a single polarizing lens. Determine whether organic matter and volcanic glass exist in the rock thin section at the same time. If so, proceed to step S3. If not, end directly.

[0049] The rock thin section identification method meets the technical requirements of "Rock Thin Section Identification: SY / T 5368-2016". Volcanic glass has certain optical properties under single polarized light, and most of the color and texture change characteristics can be observed, but it is non-optical under orthogonal polarized light. Organic matter is black in color and is non-optical under both single polarized light and orthogonal polarized light.

[0050] Step S3. Using an electron probe method, perform a surface scanning test of carbon, silicon, aluminum, and iron on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, obtain an element surface scan and the corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron, and determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0051] Step S4. Using a scanning electron microscope, identify the subionic polished sheet produced in step S1, and determine the region of amorphous material containing both volcanic glass and organic matter based on the special morphological structure of volcanic glass and organic matter. Repeat the above steps to determine at least 10 regions of amorphous material containing both volcanic glass and organic matter.

[0052] Furthermore, the rock scanning electron microscopy method meets the technical requirements of "Scanning Electron Microscope Analysis Method for Rock Samples: SY / T 5162-2021", and the special morphological structure of volcanic glass and organic matter specifically refers to: the volcanic glass has a certain gel structure, and the organic matter has a certain biological structure.

[0053] Step S5. Use an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4 to obtain an element surface scan and its corresponding percentage content of the four elements of carbon, silicon, aluminum, and iron to determine whether the area contains the four elements of carbon, silicon, aluminum, and iron at the same time.

[0054] Furthermore, the energy spectrum analysis method should meet the technical requirements of “Energy spectrum quantitative analysis method for rocks and minerals: SY / T 6189-2018”.

[0055] Step S6. Refer to the instructions attached Figure 1 A triangular diagram is made with the percentage contents of carbon, silicon and aluminum + iron as the three end members, and the percentage contents of each element obtained in step S3 and step S5 are projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram.

[0056] Step S7. Use the element distribution characteristics of the three-end member element distribution diagram to identify the origin of the amorphous material in the rock: in the three-end member element distribution diagram, if the carbon end member has more scattered points than the silicon end member and the aluminum-iron end member, then it is judged that the amorphous material is mainly formed by sedimentation; if the silicon end member has more scattered points than the carbon end member and the aluminum-iron end member, then it is judged that the origin of the amorphous material is affected by both sedimentation and volcanism; if the aluminum-iron end member has more scattered points than the carbon end member and the silicon end member, then it is judged that the amorphous material is mainly formed by volcanism.

[0057] Furthermore, if there are many scattered points of silicon end members, combined with the element surface scans in step S3 and step S5, it is determined whether the spatial position distributions of carbon and silicon elements in the element surface scans are consistent. If the distribution positions of carbon and silicon elements are completely consistent, it is determined that the amorphous material is mainly caused by sedimentation. If the distribution positions of carbon and silicon elements are completely inconsistent, it is determined that the amorphous material is mainly caused by volcanism. If the distribution positions of carbon and silicon elements are not completely consistent, it is determined that the amorphous material is affected by both volcanism and sedimentation.

[0058] In summary, after reading the present invention document, ordinary technicians in this field can make various other corresponding transformation schemes based on the technical scheme and technical concept of the present invention without creative mental labor, which all fall within the scope of protection of the present invention.

Claims

1. A method for determining the origin of amorphous material in rock, characterized by: The following steps are involved: Step S1. Select a rock sample and prepare the sample into rock powder, rock slices and sub-ion polished slices; Step S2. performing X-ray diffraction analysis on the rock powder sample to determine the amorphous content thereof; and then performing carbon-sulfur analysis to determine the organic carbon content thereof; When the measured amorphous content is negatively correlated with the organic carbon content, it indicates that the amorphous component is mainly amorphous inorganic matter, and it is judged that the amorphous is mainly caused by volcanism; When the measured amorphous content is positively correlated with the organic carbon content or has no correlation, the rock slice in step S1 is analyzed and identified to determine whether organic matter and volcanic glass exist in the rock slice at the same time. If so, proceed to step S3; Step S3. Using an electron probe method, a surface scanning test of carbon, silicon, aluminum, and iron is performed on the area of ​​the rock slice where organic matter and volcanic glass coexist in step S2, to obtain an element surface scan and the corresponding percentages of carbon, silicon, aluminum, and iron, and determine whether the area contains carbon, silicon, aluminum, and iron at the same time; Step S4. Using a scanning electron microscope, the subionic polished sheet in step S1 is identified, and the region of amorphous material containing both volcanic glass and organic matter is determined based on the special morphological structure of the volcanic glass and organic matter; Step S5. Using an energy spectrometer to perform a surface scan test of carbon, silicon, aluminum, and iron on the area in step S4, obtain an element surface scan and its corresponding percentage of carbon, silicon, aluminum, and iron, and determine whether the area contains carbon, silicon, aluminum, and iron at the same time; Step S6. A triangular diagram is made with the percentage of carbon, silicon and aluminum + iron as the three end members, and the percentage of each element obtained in step S3 and step S5 is projected into the triangular diagram in the form of scattered points to form a three-end member element distribution diagram; Step S7. Using the element distribution characteristics of the three-terminal element distribution diagram, identify the origin of the amorphous material in the rock.

2. The method for determining the origin of amorphous material in rock according to claim 1, characterized in that: In step S7, the identification of the origin of the amorphous material in the rock specifically refers to: in the three-end member element distribution diagram, if the carbon end member has more scattered points than the silicon end member and the aluminum-iron end member, it is judged that the amorphous material is mainly caused by sedimentation; if the silicon end member has more scattered points than the carbon end member and the aluminum-iron end member, it is judged that the origin of the amorphous material is affected by both sedimentation and volcanism; If the number of scattered points of the aluminum-iron end member distribution is more than that of the carbon end member and the silicon end member, it is judged that the amorphous material is mainly caused by volcanism.

3. The method for determining the origin of amorphous material in rock according to claim 2, characterized in that: If there are many scattered points of silicon end members, combined with the element surface scans in step S3 and step S5, determine whether the spatial position distributions of carbon and silicon elements in the element surface scans are consistent. If the distribution positions of carbon and silicon elements are completely consistent, it is determined that the amorphous material is mainly caused by sedimentation. If the distribution positions of carbon and silicon elements are completely inconsistent, it is determined that the amorphous material is mainly caused by volcanism. If the distribution positions of carbon and silicon elements are not completely consistent, it is determined that the amorphous material is affected by both volcanism and sedimentation.

4. A method for determining the origin of amorphous material in rock according to claim 2 or 3, characterized in that: This also includes the identification of multiple areas of amorphous material containing both volcanic glass and organic matter.

5. A method for determining the origin of amorphous material in rock according to claim 4, characterized in that: The number of areas ultimately identified that contain both volcanic glass and amorphous organic matter is at least 10.

6. The method for determining the origin of amorphous material in rock according to claim 2, characterized in that: The analysis and identification of the rock slice in step S2 specifically refers to: using a polarizing microscope, under a single polarizing lens, to analyze and identify the rock slice.

7. The method for determining the origin of amorphous material in rock according to claim 3, characterized in that: The special morphological structures of the volcanic glass and organic matter in step S4 specifically refer to: the volcanic glass has a gel structure, and the organic matter has a biological structure.

8. The method for determining the origin of amorphous material in rock according to claim 2, characterized in that: In step S6, the triangular diagram is an equilateral triangular diagram.

9. The method for determining the origin of amorphous material in rock according to claim 2, characterized in that: The thickness of the rock slice is not more than 0.035 mm, and the thickness of the subionic polishing sheet is not more than 5 mm.

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