High-precision recovery method and system for judging marine mixed deposition type shale deposition environment

Abstract

The invention provides a high-precision recovery method and system for judging the sedimentary environment of marine facies mixed-volume shale, which is characterized in that on the basis of microscopic slice fine identification, the types of minerals in a sample are preliminarily identified by XRD (X-Ray Diffraction), the mineral color change under a cathode luminescence test is combined, and the mineral composition is analyzed by XRD; three main end members of carbonate minerals, clay minerals and siliceous minerals are used for triangular projection so as to identify main lithofacies types of the mixed-volume shale and plane distribution characteristics of various lithofacies; through TOF-SIMS, micro-area mineral composition and micro-area element change identification in the mixed shale is carried out, and a biomarker compound in organic geochemistry is used for sedimentary environment identification, so that sedimentary environment change corresponding to complex lithofacies change of the mixed shale is identified, and the formation mechanism of the mixed shale is clarified.

Description

Technical Field

[0001] The present invention belongs to the technical field of shale oil and gas exploration, and in particular relates to a high-precision recovery method and system for judging the sedimentary environment of marine mixed shale. Background Art

[0002] Marine shales are formed by the deposition of fine-grained sediments in a marine environment. Understanding the depositional environment of marine shales is of great significance for interpreting geological history, predicting the distribution of shale gas and shale oil resources, and reconstructing paleoclimate and paleoenvironment. Methods for studying the depositional environment of marine shales include geological surveys, petrological analysis, geochemical analysis, paleontological analysis, physical property analysis, paleoclimate reconstruction, numerical simulation, and stratigraphic correlation. The mass extinction event at the turn of the Permian-Triassic (P-Tr) was the most serious catastrophe suffered by life on Earth since the Phanerozoic. The complete recovery of the marine ecosystem was very slow, lasting more than about 5 million years in the Early Triassic. After entering the Middle Triassic Anni period, the recovery rate suddenly accelerated, and marine diversity and ecosystems continued to recover. The transition from the Early Triassic to the Middle Triassic is marked by a layer of altered acidic tuff, which can be identified in most outcrops in the Sichuan Basin and neighboring provinces such as Guizhou. Based on the biostratigraphy of conodonts, magnetostratigraphy, and zircon uranium / lead ages, the age of the Early-Middle Triassic line is believed to be 247.21±0.1 meters, which marks the beginning of the Anisian period. The Anisian period is generally characterized by the deposition of shallow-water carbonates, but a set of mixed shales was deposited in the Lei III period. The reason for the deposition of this set of shales is still unclear, which greatly restricts the exploration and development of oil and gas in this section.

[0003] The methods for studying the sedimentary environment of marine shale cover multiple disciplines, including geology, petrology, geochemistry, paleontology, physical property analysis, paleoclimate reconstruction, numerical simulation and stratigraphic correlation. Field geological surveys are the basis of research. Through detailed observation and description of outcrops and drill cores, researchers can understand the sequence, lithology changes, sedimentary structures and structural deformation of shale. This information is crucial for identifying sedimentary phases and understanding the evolution of sedimentary environments. Stratigraphic analysis determines the time and spatial distribution of sedimentary events by studying the sequence and stratigraphic relationships of shales, revealing the geological connections between different regions. Petrological analysis includes thin section identification and scanning electron microscopy (SEM) analysis. Thin section identification uses a microscope to observe shale thin sections, identify mineral composition and structural characteristics, and provide detailed mineralogical and petrological information. SEM analysis provides high-resolution shale surface morphology, identifies tiny particles and structures, and reveals the microscopic characteristics of shale. Geochemical analysis is an important means to study the sedimentary environment of marine shale. Elemental geochemical analysis uses X-ray fluorescence spectroscopy (XRF), inductively coupled plasma mass spectrometry (ICP-MS) and other techniques to determine the element content in shale and understand the chemical conditions of the sedimentary environment. Isotope geochemical analysis determines the isotope ratios of carbon, oxygen, sulfur, etc. to infer paleoclimate, paleo-ocean chemistry and the source of organic matter. Organic geochemical analysis uses pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) and other techniques to analyze organic matter in shale to understand biological productivity and organic matter preservation conditions. Paleontological analysis provides biological evidence of the sedimentary environment by studying microfossils and sporopollen fossils in shale. Microfossil analysis studies plankton fossils such as ostracods, foraminifera and algae to infer the biological characteristics of the sedimentary environment. Sporopollen analysis understands paleoclimate and paleovegetation by analyzing sporopollen fossils in shale, and provides information on terrestrial vegetation and climate change. Physical property analysis includes particle size analysis and magnetic susceptibility measurement. Particle size analysis uses equipment such as laser particle size analyzers to measure the particle size distribution of shale and infer the energy conditions of the sedimentary environment. Magnetic susceptibility measurements provide physical evidence for understanding the origin and formation of sediments by measuring the magnetic susceptibility of shales. Paleoclimate reconstruction infers climate change during deposition by analyzing the color, organic matter content, and carbonate content of shales. Sediment color and organic matter content can provide intuitive evidence of climate change, while carbonate content determination reveals the chemical environment and climate change of the ancient ocean.

[0004] In the general sense, mixed sediments refer to the mixing of terrigenous debris and carbonates (including alienated particles, etc.) in sedimentation. Mixed sediments can be divided into narrow and broad sense: the narrow sense refers to the mixing of terrigenous debris and carbonate components (in the same rock layer), and the broad sense includes the mixing of regular and terrigenous debris and carbonate layers to form overlapping interlayers or interlayers. Therefore, the deposition of mixed shale is diverse and complex.

[0005] Field geological surveys are the basis of research. Through the observation and description of outcrops and drill cores, we can understand the stratigraphic sequence and sedimentary structure of shale. However, outcrops and drill cores may not be continuous and cannot fully reflect the spatial variation of shale. In addition, field surveys require a lot of time and human resources, and the survey results may be limited by factors such as climate, topography and vegetation, affecting the comprehensiveness and accuracy of the survey.

[0006] Stratigraphic analysis determines the evolution of the sedimentary environment by studying the sequence and stratigraphic relationships of marine shales. However, stratigraphic correlation is limited by the quantity and quality of outcrop and drilling data, and there may be uncertainty in stratigraphic correlation in different areas. Discontinuity between strata and complex structural deformation may also make the interpretation of the sedimentary environment more difficult.

[0007] Petrological analysis includes thin section identification and scanning electron microscope (SEM) analysis. Thin section identification observes shale thin sections through a microscope to identify mineral composition and structural characteristics. However, sample preparation and identification require high-level technology and equipment, and thin section observation can only provide local information and cannot fully reflect the overall characteristics of shale. SEM analysis provides high-resolution shale surface morphology and can identify tiny particles and structures, but it requires special equipment and sample preparation, data processing and interpretation are complex, and the observation area is limited.

[0008] Geochemical analysis includes elemental geochemistry, isotope geochemistry and organic geochemistry. Elemental geochemical analysis can provide rich chemical information, but the element distribution may be affected by later diagenesis, and chemical analysis requires high-precision equipment and strict experimental conditions. Isotope geochemical analysis can provide detailed information about sedimentary environment and biological activities, but it requires high-precision equipment and technology, and the data interpretation is complex and may be affected by many factors. Organic geochemical analysis can reveal biological activities and organic matter preservation conditions in ancient environments, but organic matter is easily affected by later diagenesis, the analysis process is complex, and the results may be difficult to interpret.

[0009] Paleontological analysis includes microfossil analysis and pollen analysis. Microfossil analysis can provide biological evidence of the sedimentary environment, but the preservation of microfossils varies and may be affected by bioturbation and chemical changes in the later stages of deposition. Pollen analysis can provide information about terrestrial vegetation and climate change, but the preservation conditions of pollen fossils are harsh, and sample processing and identification require a high level of technology.

[0010] Physical property analysis includes grain size analysis and magnetic susceptibility measurement. Grain size analysis can provide information about the energy conditions of the sedimentary environment, but it requires high-precision equipment and strict sample preparation, and the results may be affected by the representativeness of the sample. Magnetic susceptibility measurement can provide physical evidence about the source and origin of the sediment, but it is affected by the mineral composition, and the interpretation of the results needs to be combined with other data.

[0011] Paleoclimate reconstruction infers climate change during deposition by analyzing the color, organic matter content, and carbonate content of shales. Analysis of color and organic matter content can provide intuitive evidence of climate change, but they are easily affected by later diagenesis and the analysis results may be unstable. Carbonate content analysis can provide information about the marine chemical environment and climate change, but due to the influence of sedimentary environment and diagenesis, the analysis results need to be interpreted with caution.

[0012] Numerical simulation uses geological model software to simulate the sedimentary process and reconstruct the paleoenvironment. Numerical simulation can reconstruct the sedimentary environment in time and space and provide quantitative research results, but it requires a lot of data and parameters, and the model results are affected by input data and assumptions. Stratigraphic correlation determines the temporal and spatial distribution of sedimentary events by comparing shale sequences in different regions, which can reveal the geological connection between regions, but due to the quantity and quality of outcrop and drilling data, there may be uncertainty in the stratigraphic correlation of different regions.

[0013] Therefore, the methods and techniques for studying the sedimentary environment of marine shale each have their own limitations. Each method has its own limitations. Researchers need to further select appropriate methods according to specific circumstances in practical applications and comprehensively consider the impact of various factors on the results. By continuously optimizing and improving research methods, we can improve our understanding of the sedimentary environment of marine shale. Summary of the invention

[0014] The present invention provides a high-precision restoration method and system for judging the marine mixed-accumulation shale depositional environment, which comprehensively utilizes a variety of technologies and methods, and combines geological surveys, petrological analysis, geochemical analysis, paleontological analysis, physical property analysis, paleoclimate reconstruction, numerical simulation and stratigraphic comparison, etc.; it can not only provide detailed information about the paleoenvironment, but also provide an important basis for resource exploration and geological history research.

[0015] To solve the above problems, the technical solution provided by the present invention is as follows:

[0016] The embodiment of the present invention provides a high-precision recovery method for determining the sedimentary environment of marine mixed shale, comprising the following steps:

[0017] Step S1, using XRD to preliminarily identify the marine mixed shale lithofacies, and analyzing the vertical distribution law of the marine mixed shale; using the total organic carbon TOC test to identify the abundance of organic matter in each lithofacies of the marine mixed shale; using XRD to analyze its mineral composition, and using the three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation to identify the main lithofacies types of the mixed shale, and judging the general sedimentary environment evolution trend based on the mineral content; judging and identifying the planar distribution characteristics of various lithofacies of the mixed shale based on the selection of cores from multiple wells;

[0018] Step S2, using time-of-flight secondary ion mass spectrometry TOF-SIMS to identify the changes in micro-region mineral composition and micro-region elements within the mixed shale, and using biomarker compounds in organic geochemistry to identify the sedimentary environment recovery mechanism corresponding to the complex facies changes of the mixed shale.

[0019] According to an optional embodiment of the present invention, step S1 also includes: cathode luminescence as a means of identifying terrigenous input, different minerals will show different colors and spectral characteristics under cathode luminescence, which is helpful to identify the mineral type and its distribution; taking quartz as a landmark mineral, under cathode luminescence, terrigenous detrital quartz has strong luminescence phenomenon, and micron-level biogenic quartz has no luminescence phenomenon.

[0020] According to an optional embodiment of the present invention, step S2 specifically includes: step S21, using biomarker compounds to restore the overall change trend of its sedimentary environment, and using different types of mixed shale facies saturated hydrocarbon chromatography and mass spectrometry to determine the differences in organic matter sources and environmental changes.

[0021] According to an optional embodiment of the present invention, step S21 specifically includes: a first step, obtaining the results of chromatographic and mass spectrometric analysis of shale saturated hydrocarbons, and using the carbon number set index range in the analysis results to determine whether the organic matter belongs to the terrestrial phase or the marine phase; a second step, using pristane Pr / C17 and phytane Ph / C18 in the biomarker compounds for preliminary environmental identification, and using Pr / Ph for preliminary identification of reducibility; when the pristane-phytane ratio Pr / Ph is less than 0.5, it reflects a strongly reducing environment, when Pr / Ph is between 0.5 and 2, it is a reducing environment, and when Pr / Ph is greater than 2, it is manifested as terrestrial organic matter input in an oxidizing environment, and using The ratio of Pr / nC17 to Ph / nC18 can be used to identify the specific source of organic matter. The third step is to select two mass-to-charge ratio conditions for analysis in the mass spectrum, namely m / z=217 and m / z=191. In the mass spectrum analysis results of saturated hydrocarbons at m / z=217, the sterane composition and distribution characteristics can well reveal the evolution process of the source rock and the sedimentary environment. The source of C27R sterane is mainly lower aquatic organisms of algae organisms, C28R sterane is mainly terrestrial higher plants, and C29R sterane is mainly related to blue-green algae. The distribution characteristics of the three steranes can intuitively judge the source of organic matter, thereby determining the sedimentary environment.

[0022] According to an optional embodiment of the present invention, step S2 specifically also includes: step S22, determining the multi-dimensional coupling recovery mechanism of the marine mixed shale sedimentary environment, using TOF-SIMS to conduct micro-area testing on the trace elements of the sample, and performing high-precision restoration of the sedimentary environment changes represented by the test point.

[0023] According to an optional embodiment of the present invention, step S22 specifically includes:

[0024] The main and trace element values ​​identified by TOF-SIMS are used to study the redox properties of water bodies. Before using trace element substitute indicators to indicate the sedimentary environment, the trace elements are usually corrected using Ti elements to calculate non-detrital or excess elements and obtain corresponding excess values, thereby eliminating the interference of terrigenous materials.

[0025] The variation patterns of the ratios of U / Th, Ni / Co, V / Cr, V / (V+Ni) and the enrichment of V, Ni, Mo and U in the elements are used for discrimination. The above letters represent chemical elements, U represents uranium, V represents vanadium, Ni represents nickel, Mo represents molybdenum, Co represents cobalt, and Cr represents chromium.

[0026] The CIA index, which indicates weathering intensity, is used as a paleoclimate identification mark. When the climate is humid, chemical weathering will be enhanced.

[0027] Relevant indicators are used to restore the ecological level during the sedimentation period. P / Ti is used as a positive correlation indicator of ancient marine primary productivity to restore the ecological level as a verification indicator of sedimentary water changes. Organic matter carbon isotopes and nitrogen isotopes are used as identification indicators, where P represents phosphorus and Ti represents titanium.

[0028] The embodiment of the present invention also provides a high-precision recovery system for judging the sedimentary environment of marine mixed shale, which includes a system for judging the lithofacies characteristics of mixed shale and a system for judging the sedimentary environment of mixed shale;

[0029] The system for identifying the lithofacies characteristics of mixed shale is used to: use XRD to preliminarily identify the lithofacies of marine mixed shale, and analyze the vertical distribution law of marine mixed shale; use the total organic carbon TOC test to identify the organic matter abundance of each lithofacies of marine mixed shale; use XRD to analyze its mineral composition, and use the three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation to identify the main lithofacies types of mixed shale, and judge the general sedimentary environment evolution trend according to the mineral content; based on the selection of multiple well cores, judge and identify the planar distribution characteristics of various lithofacies of mixed shale;

[0030] The system for identifying mixed shale sedimentary environment restoration is used to: identify the changes in micro-region mineral composition and micro-region elements inside mixed shale through time-of-flight secondary ion mass spectrometry TOF-SIMS, and use biomarker compounds in organic geochemistry to identify the sedimentary environment changes corresponding to the complex facies changes of mixed shale, so as to clarify the formation mechanism of mixed shale.

[0031] An embodiment of the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a high-precision recovery method for determining a marine mixed-accumulation shale depositional environment as in the above-mentioned embodiment is implemented.

[0032] An embodiment of the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, a high-precision recovery method for determining a marine mixed shale depositional environment as described in the above embodiment is implemented.

[0033] Compared with the prior art, the embodiments of the present invention provide a high-precision restoration method and system for judging the sedimentary environment of marine mixed shale, which has at least the following beneficial effects: (1) TOF-SIMS improves the research accuracy of mixed shale sedimentary environment to nanometer level, greatly improving the resolution of sedimentary environment restoration; (2) Linked research is carried out from multiple dimensions of water body, climate, material source and ecology to improve the reliability of environmental restoration. (3) Biomarker compounds can corroborate with inorganic geochemical indicators from the perspective of organic matter evolution, and the longitudinal shift changes of C and N isotopes can also be used for corroboration. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 A flow chart of a high-precision recovery method for determining a marine mixed shale depositional environment provided in an embodiment of the present application.

[0036] Figure 2 A three-end member diagram of shale lithofacies division for a high-precision recovery method for determining a marine mixed shale depositional environment provided in an embodiment of the present application.

[0037] Figures 3 to 6 This is a normal alkane distribution diagram provided for the examples of this application.

[0038] Figure 7 A deposition environment identification diagram using Pr / nC17 and Ph / nC18 is provided for an embodiment of the present application.

[0039] Figures 8 to 11 The mass spectra of saturated hydrocarbons m / z=191 and m / z=217 provided in the examples of the present application.

[0040] Fig.12This is the mineral change trend identification and lithofacies division provided in the embodiments of the present application.

[0041] Fig.13 The three-unit diagrams of La-Th-Sc, Th-Sc-Zr / 10, and Th-Co-Zr / 10 provided for the embodiments of the present application.

[0042] Fig.14 This is a coupling identification diagram of the redox conditions of sedimentary water bodies provided in an embodiment of the present application.

[0043] Fig.15 The coupling identification diagram of paleoclimate and productivity during the sedimentary period provided in the embodiment of the present application

[0044] Fig.16 A schematic diagram of a high-precision recovery system for determining a marine mixed shale depositional environment provided in an embodiment of the present application.

[0045] Fig.17 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0047] The present invention takes the marine mixed shale of the Leikoupo Formation in the Sichuan Basin as an example. On the basis of petrology, sedimentology and geochemistry research, the XRD experiment, major and trace element analysis, CN isotope analysis, TOC test and biomarker compound analysis are comprehensively used to clarify the sedimentary distribution characteristics and mineral composition of the mixed shale. On the basis of identifying the major and trace elements by TOF-SIMS, the trace elements are usually corrected by Ti element for calculating non-detrital or excess elements and obtaining corresponding excess values, thereby eliminating the interference of terrigenous materials and completing the high-precision correction of the sedimentary environment. On the basis of accurately restoring the sedimentary environment of the mixed shale, the material source is also effectively identified, and finally a set of methods for accurately restoring the sedimentary environment of the mixed shale unconventional reservoir discovered for the first time in the Sichuan Basin is formed.

[0048] The indoor testing and analysis methods adopted by the present invention are as follows: Polarized light microscope: used to observe the microstructure of mixed shale and identify the mineral composition. The DM4500P polarized light microscope produced by Leica of Germany purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering can meet the needs of the present invention. High-resolution scanning electron microscope (SEM): used to observe the ultra-microscopic morphology and structure of dolomite and gypsum salt rock minerals. The Quanta250 FEG field emission scanning electron microscope manufactured by FEI of the United States purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering has a resolution of up to 1.2nm, a maximum magnification of up to 1 million times, and can be imaged instantly, which can meet the research needs of the present invention. X-ray diffraction (XRD): used to identify the mineral composition of different mixed shale phases and clarify the changes in the content of some elements (Fe, Mn, etc.). The Japanese Rigaku D / Max IIICX-ray diffractometer purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering has successfully provided services for many scientific research projects with high testing accuracy. Electron Probe Analysis (EPMA): It can obtain the micro-area morphology image of the measured area, the corresponding composition, and the quantitative analysis of the constituent elements. The National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering purchased the latest product EPMA-17200HSeries electron probe micro-area analyzer produced in Japan, with element analysis range: 5B-92U, analysis accuracy: main elements (content>5%), can reach ≤1%. Major and trace elements: can be used to study the ancient sedimentary environment of shale, element migration rules, property discrimination, etc. The National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering is equipped with TOF-SIMS to meet the research needs of this project. Organic matter C and N isotope analysis: used to analyze the ancient environment and trace carbon source, and determine the properties and sources of fluids. The MAT 253 isotope mass spectrometer purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering can meet the needs of C and N isotope determination of this project.

[0049] Biomarker compounds: Identify the sedimentary environment and the source of organic matter, clarify the rules of organic matter enrichment, and complete the study of the genesis of high-quality lithofacies. The ISQ gas chromatograph-mass spectrometer produced by ThermoFisher, USA, purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering of Southwest Petroleum University, can provide support for this research. TOC detection: Clarify the abundance of organic matter in marine mixed shale lithofacies, and use it to determine the basic characteristics of the hydrocarbon generation conditions of mixed shale. The CS230SH organic carbon and sulfur analyzer produced by Leco, USA, purchased by the National Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering of Southwest Petroleum University, can provide support for this. TOF-SIMS quantitative analysis technology for trace elements in micro-areas: Clarify the composition and variation characteristics of the main and trace elements in the micro-areas of mixed shale lithofacies, and use it to restore the sedimentary environment characteristics of mixed shale together with C, N isotopes and biomarker compounds. It can be carried out in the National Key Laboratory of Chengdu University of Technology.

[0050] The research ideas of the present invention are as follows:

[0051] The particularity of mixed shale oil and gas reservoirs lies in their complex properties such as complex rock structure, diverse reservoir combinations, high exploration difficulty, and low level of understanding. Domestic oil and gas exploration in this field has not made a breakthrough. After years of research by the project team, the silence of oil and gas exploration in marine tight limestone for nearly half a century was broken. At the end of 2020, unconventional mixed shale oil and gas reservoirs were discovered for the first time in the third section of the Leikoupo Formation in the Sichuan Basin, and industrial oil and gas flows (40 tons of oil and 108,700 cubic meters of tight gas) were obtained. Mixed shale has superior conditions such as coexistence of oil and gas, self-generation and storage, and shallow exploration depth. The condensate oil produced in this section has created the highest condensate oil production record in the marine strata of the Sichuan Basin, opening up a new field of marine unconventional oil and gas exploration in the Sichuan Basin, which is of great significance to ensuring national energy security and helping to realize the vision of the oil and gas industry and the goal of building a dual-city economic circle in the Chengdu-Chongqing region. However, there is currently a lack of research methods for the genetic mechanism of mixed shale oil and gas reservoirs. The diversity and complexity of mixed mineral assemblages may result in the deposition of multiple layers and multiple different mineral assemblages in the same sample. Therefore, the traditional method of using XRD and major and trace elements to identify lithofacies is difficult to increase the accuracy of identification of mixed shale lithofacies and sedimentary environment, and can only reflect the macroscopic characteristics of sedimentary environment changes. This greatly limits the research on the formation mechanism of mixed shale. The unclear formation mechanism leads to the prediction of the distribution range of this set of mixed shale oil and gas reservoirs, which limits the exploration and development of this type of unconventional oil and gas. Therefore, it is urgent to find a research method that is more suitable for mixed shale.

[0052] The present invention innovatively uses XRD to preliminarily identify the mineral types in the sample based on the fine identification of thin sections under a microscope, and preliminarily carries out lithofacies division in combination with the mineral color changes under the cathode luminescence test; TOF-SIMS (time-of-flight secondary ion mass spectrometry) is used to identify the micro-regional mineral composition and micro-regional element changes inside the mixed shale, and biomarker compounds in organic geochemistry are used to jointly identify the sedimentary environment, so as to identify the changes in the sedimentary environment corresponding to the complex lithofacies changes of the mixed shale, thereby clarifying the formation mechanism of the mixed shale.

[0053] (1) TOF-SIMS (time-of-flight secondary ion mass spectrometry) is a powerful analytical tool, especially in the field of elemental analysis, and has many significant advantages over traditional analytical instruments. The advantage of TOF-SIMS in spatial resolution is particularly prominent. Although traditional elemental analysis methods, such as X-ray fluorescence spectroscopy (XRF) or inductively coupled plasma mass spectrometry (ICP-MS), are excellent in the sensitivity and accuracy of elemental detection, they usually cannot achieve nanometer-level spatial resolution. TOF-SIMS also has three-dimensional imaging capabilities, which is not possible with many traditional analytical instruments. By peeling off the sample layer by layer and analyzing the chemical composition of each layer, TOF-SIMS can construct a three-dimensional chemical composition distribution map of the sample. This high spatial resolution and three-dimensional imaging capability enable TOF-SIMS to study a certain mineral mixed in the shale separately, and to more accurately understand the elemental composition characteristics of a single mineral. Traditional mass spectrometry analysis technology may be interfered by background signals when detecting trace elements in samples, resulting in an increase in the detection limit. However, TOF-SIMS can very sensitively detect extremely trace elements and isotopes in samples, and its detection limit can reach ppm (parts per million) or even lower levels.

[0054] (2) Although the biomarker compounds in organic geochemistry only account for 1% of crude oil, the sedimentary environment of this set of mixed shale can be inverted based on their fingerprint characteristics. For example, pristane Pr and phytane Ph in acyclic isoprene alkanes can reflect the sedimentary environment of the water body. When the Pr / Ph ratio is less than 0.5, it indicates a strongly reducing environment. When the Pr / Ph value is between 0.5-1.0, it indicates a reducing environment; when the Pr / Ph value is between 1.0--2.0, it represents a weakly reducing and weakly oxidizing condition; and when Pr / Ph>2.0, it implies an oxidizing environment; the value of samples from the marine phase is generally less than 0.8. However, the Pr / Ph ratio is affected by other factors besides the redox conditions, so other indicators are needed for joint evidence. High abundance of 28,30-dinorhopane (BNH) and 25,28,30-trinorhopane (TNH) are typical characteristics of source rocks deposited under anoxic conditions. The preservation and distribution of the C31-C35 long-chain hopane series can be used to infer the redox conditions when the source rocks were deposited. The high abundance of C35 ascending hopane can also be interpreted as a general indicator of a strongly reducing (low Eh>) marine environment during the deposition period. The C29 / C30 and C35 / C34 hopane ratios can also be used together to determine the sedimentary environment characteristics of mixed shales. Gammacerane in biomarker compounds is also often used to characterize stratified water bodies during shale deposition, and the (high value) of gammacerane / C30αβhopane is also often used to judge that the sedimentary environment has strong reduction and high salinity. The content of pregnane and ascending pregnane is related to the degree of salinization of the water body. If the content of both in the biomarker compounds is high, it means that the salinity is high.

[0055] In addition, the C and N isotopes can also reflect the sedimentary environment. The positive or negative deviations in the vertical direction can also indicate changes in the ecological level and primary productivity. For example, when both C and N isotopes have positive deviations, it indicates a weakening of the ecological level and primary productivity.

[0056] Therefore, the identification of minerals in thin sections under a microscope is combined with XRD for preliminary petrographic division. The color changes of minerals under cathodoluminescence testing can be used to quickly identify the changes in mineral composition of different strata in the vertical direction of the shale. TOF-SIMS (time-of-flight secondary ion mass spectrometry) is used to identify the changes in micro-area mineral composition and micro-area elements in mixed shales, and biomarker compounds in organic geochemistry are used to jointly identify the sedimentary environment. Finally, C and N isotopes can be used to support the sedimentary environment.

[0057] In order to identify the changes in the sedimentary environment corresponding to the complex lithofacies of mixed shale, the formation mechanism of mixed shale can be clarified. Based on the fine identification of petrological characteristics, the combination of multiple methods can significantly improve the accuracy of identifying lithofacies and sedimentary environments of marine mixed shale. This result can be used to clarify the formation mechanism of mixed shale and effectively predict the distribution range of unconventional oil and gas reservoirs of marine mixed shale.

[0058] According to the above-mentioned indoor test analysis means and research ideas, the embodiment of the present invention provides a high-precision recovery method for judging the marine mixed accumulation type shale deposition environment, such as Figure 1 As shown, the following steps are included:

[0059] Step S1, using XRD to preliminarily identify the marine mixed shale facies, and analyzing the vertical distribution of the marine mixed shale; using the total organic carbon TOC test to identify the abundance of organic matter in each facies of the marine mixed shale; using XRD to analyze its mineral composition, and using the three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation (reference Figure 2 ) to identify the main lithofacies types of mixed shale and judge the general evolution trend of sedimentary environment according to the mineral content; on the basis of selecting cores from multiple wells, judge and identify the planar distribution characteristics of various lithofacies of mixed shale;

[0060] Step S2, using time-of-flight secondary ion mass spectrometry TOF-SIMS to identify the changes in micro-region mineral composition and micro-region elements within the mixed shale, and using biomarker compounds in organic geochemistry to identify the sedimentary environment changes corresponding to the complex facies changes of the mixed shale, so as to clarify the formation mechanism of the mixed shale.

[0061] Step S1 also includes: cathode luminescence as a means of identifying terrigenous inputs. Different minerals will show different colors and spectral characteristics under cathode luminescence, which is helpful to identify mineral types and their distribution; quartz is used as a landmark mineral. Under cathode luminescence, terrigenous detrital quartz has a strong luminescence phenomenon, and micron-level biogenic quartz has a non-luminescence phenomenon. In this embodiment, first, the mixed shale core section to be analyzed is selected for core observation and sampling. Subsequently, thin sections are prepared for microscopic observation, and cathode luminescence technology is used to reveal the detailed composition and microstructural characteristics of minerals in the shale. Using thin section microscopic observation combined with cathode luminescence, minerals that are difficult to distinguish under conventional optical microscopes, such as quartz, calcite, feldspar and barite, can be identified and distinguished. Most importantly, cathode luminescence can be used as a means of identifying terrigenous inputs.

[0062] Step S2 specifically includes: Step S21, using biomarker compounds to restore the overall change trend of its sedimentary environment, and using different types of mixed shale facies saturated hydrocarbon chromatography and mass spectrometry to determine the differences in organic matter sources and environmental changes.

[0063] Step S21 specifically includes: Figure 3 , Figure 4 , Figure 5 and Figure 6As shown, the first step is to obtain the results of shale saturated hydrocarbon chromatography and mass spectrometry analysis, and use the carbon number set index range in the analysis results to determine whether the organic matter belongs to the terrestrial or marine phase. In the chromatogram in this embodiment, the carbon number of normal alkanes is identified by using the characteristics of nC17 adjacent to Pr and nC18 adjacent to Ph. Subsequently, the carbon number distribution characteristics of normal alkanes are used to perform preliminary identification of the source of organic matter. When the carbon number is concentrated below nC20, it generally represents aquatic organisms (mainly algae and lower aquatic organisms), nC23-nC25 represents emergent plants, nC27-nC29 represents terrestrial higher plants (arbor), and those greater than nC31 represent terrestrial herbaceous plants.

[0064] like Figure 7 As shown, in the second step, pristane Pr / C17 and phytane Ph / C18 in the biomarker compounds are used for preliminary environmental identification, and Pr / Ph is used for preliminary identification of reducibility; when the pristane-phytane ratio Pr / Ph is less than 0.5, it reflects a strong reducing environment, Pr / Ph is between 0.5 and 2 for a reducing environment, and Pr / Ph is greater than 2 for terrigenous organic matter input in an oxidizing environment, and the ratio of Pr / nC17 to Ph / nC18 is used to identify the specific source of organic matter;

[0065] like Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, in the third step, in the mass spectrum, two mass-to-charge ratio conditions are selected for analysis, namely m / z=217 and m / z=191. In the mass spectrometry analysis results of saturated hydrocarbons at m / z=191, the gammacerane index GI is used as an identification index of water salinity, and the calculation method is GI=gammacerane / C30 horane. Gammacerane is a C30-tri-mushroom alkane of the non-horane series. The level of the gammacerane index is closely related to the salinity and stratification of the water body during the deposition of organic matter. The gammacerane content of the source rock in the freshwater sedimentary environment is usually low, while the gammacerane content of the source rock in the saltwater sedimentary environment is usually high. The gammacerane index (gammacerane / C30 horane) is generally close to 1 or greater than 1.

[0066] High abundance of 28,30-dinorhopane (BNH) and 25,28,30-trinorhopane (TNH) is a typical feature of source rocks deposited under anoxic conditions. 31 -C 35 The preservation and distribution of the long-chain hopane series can be used to infer the redox conditions during the deposition of the source rock. The high abundance of C35 hopane can also be interpreted as a general indicator of a strongly reducing (low Eh>) marine environment during the deposition period. 29 / C 30 and C 35 / C 34Hopane ratios can also be used to determine the sedimentary environment characteristics of mixed shales.

[0067] In the mass spectrometry analysis results of saturated hydrocarbons at m / z=217, the composition and distribution characteristics of steranes can well reveal the evolution of the source rock and the sedimentary environment. The source of C27R steranes is mainly lower aquatic organisms such as algae organisms, C28R steranes are mainly terrestrial higher plants, and C29R steranes are mainly related to blue-green algae. The distribution characteristics of the three steranes can intuitively determine their organic sources and thus determine the sedimentary environment. The general form of the marine phase is L-type, and the terrestrial phase is generally V-type. For example, in the mass spectrum of biomarker compounds of the third section of the Leikoupo Formation in the Sichuan Basin, regular steranes show an "L" type, indicating a marine source.

[0068] Step S2 specifically includes: Step S22, determining the multi-dimensional coupling recovery mechanism of the marine mixed shale sedimentary environment, using TOF-SIMS to conduct micro-area testing of the trace elements of the sample, and performing high-precision recovery of the sedimentary environment changes represented by the test point, referring to Fig.12 .

[0069] Step S22 specifically includes:

[0070] like Fig.13 As shown in the figure, the three-unit diagram of La-Th-Sc, Th-Sc-Zr / 10, and Th-Co-Zr / 10 is used to identify the main sources of elements, which are matched with the identification of terrestrial input in cathode luminescence to verify the source of quartz; for example, in the study of mixed shale of the Leikoupo Formation in the Sichuan Basin, the core of the HC125 well was selected for identification, and it was determined that the source mainly came from the continental island arc, thereby clarifying the environmental characteristics around the depositional area.

[0071] The main trace element values ​​identified by TOF-SIMS are used to study the redox properties of water bodies. Before using trace element substitute indicators to indicate the sedimentary environment, the trace elements are usually corrected using Ti elements to calculate non-detrital or excess elements and obtain corresponding excess values, thereby eliminating the interference of terrigenous materials; the correction formula used is: Element xs =Element total -Ti total ×(Element / Ti)PASS. Where Element and Total Element are the non-detrital content and total content of the element in the sample, respectively. (Element / Ti) is the ratio of the element to titanium in the Post-Archaean Australian Shale (PAAS).

[0072] like Fig.14As shown in the figure, in order to explain the degree of water restriction and redox conditions, the variation patterns of the ratios of U / Th, Ni / Co, V / Cr, V / (V+Ni) and the enrichment of V, Ni, Mo and U are used for discrimination; Ni / Co ratio <5 represents an oxidizing environment, ratios between 5 and 7 represent a sub-oxidizing environment, and ratios >7 represent an anoxic environment. V / Cr <2 indicates an oxidizing environment, 2 to 4.25 indicates a sub-oxidizing environment, and >4.25 indicates an anoxic environment. Mo precipitation is very likely to occur in sulfidic water bodies. Due to the difference in the chemical properties of Mo and U, they react differently to redox conditions. Therefore, different sedimentary environments can be identified based on the degree of authigenic enrichment of Mo and U in sediments. The enrichment of an element can be expressed by the enrichment factor, enrichment factor XEF = (X / Al) sample / (X / Al) average, where (X / Al) average represents the normalization of the sample with the average shale component of Australia in the post-Archaean to minimize the dilution effect of carbonate or biogenic silica. For example, in the study of the third section of the Leikoupo Formation in the Sichuan Basin, our team used the correlation between MoEF and UEF to identify that the shale was deposited in a semi-confined environment. It was also correlated with TOC in organic geochemical tests to improve the accuracy of the macroscopic vertical changes in the sedimentary environment of marine mixed shale, where U represents uranium, V represents vanadium, Ni represents nickel, Mo represents molybdenum, Co represents cobalt, Cr represents chromium, and Al represents aluminum.

[0073] like Fig.15 As shown in the figure, the CIA index indicating weathering intensity is used as a paleoclimate identification mark. When the climate is humid, chemical weathering will be enhanced. Before calculating the CIA value, it is necessary to exclude the alteration of sedimentation during circulation and sorting and sedimentation and diagenesis. Only in this way can the measured CIA value be used to judge the paleoclimate and weathering degree. The CIA expression is: CIA = mole [Al2O3 / (Al2O3+CaO * +Na2O+K2O)]×100. In the formula: each element is expressed in molar fraction, CaO * Indicates the molar fraction of CaO in silicate. For the calculation and correction of CaO, the formula is used: CaO * =mole CaO-mole P2O5×10 / 3. Among them, CaO * Correction: If the corrected molar number of CaO is less than the molar number of Na2O, the corrected molar number of CaO is used as the molar number of CaO; otherwise, the molar number of Na2O is used as the molar number of CaO.

[0074] Relevant indicators are used to restore the ecological level during the sedimentation period. P / Ti is used as a positive correlation indicator of ancient marine primary productivity to restore the ecological level as a verification indicator of sedimentary water changes, where P represents phosphorus and Ti represents titanium; organic matter carbon isotopes and nitrogen isotopes are used as identification indicators. 12 C and 14 N, when life activities are strong, 12 C and 14 N will be relatively enriched, and a negative bias trend will appear. When a negative bias trend appears, it is judged that the ecological level is gradually enhanced, otherwise it is weakened. For example, in the core research of the HC125 well of the Leikoupo Formation in the Sichuan Basin, the present invention identified the P / Ti variation law and the weakening of the ecological level and primary productivity when both C and N isotopes were positively biased.

[0075] As mentioned above, the present invention takes the marine mixed shale of the Leikoupo Formation in the Sichuan Basin as an example. On the basis of petrology, sedimentology, and geochemistry research, it comprehensively uses XRD experiments, major and trace element analysis, CN isotope analysis, TOC test, and biomarker compound analysis to clarify the sedimentary distribution characteristics and mineral composition of the mixed shale. On the basis of using TOF-SIMS to identify the main and trace elements, the trace elements are usually corrected using the Ti element to calculate non-detrital or excess elements and obtain corresponding excess values, thereby eliminating the interference of terrigenous materials and completing high-precision correction of the sedimentary environment. On the basis of accurately restoring the sedimentary environment of the mixed shale, the material source is also effectively identified, and finally a set of methods for accurately restoring the sedimentary environment of the mixed shale unconventional reservoir discovered for the first time in the Sichuan Basin is formed.

[0076] like Fig.16 As shown, an embodiment of the present invention also provides a high-precision recovery system for judging the sedimentary environment of marine mixed shale, which includes a system for identifying the lithofacies characteristics of mixed shale and a system for identifying and restoring the sedimentary environment of mixed shale.

[0077] The system for identifying lithofacies characteristics of mixed shale is used to: use XRD to preliminarily identify lithofacies of marine mixed shale, and analyze the vertical distribution law of marine mixed shale; use total organic carbon TOC test to identify the organic matter abundance of each lithofacies of marine mixed shale; use XRD to analyze its mineral composition, and use three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation to identify the main lithofacies types of mixed shale, and judge the general evolution trend of sedimentary environment according to the mineral content; based on the selection of cores from multiple wells, judge and identify the planar distribution characteristics of various lithofacies of mixed shale.

[0078] The system for identifying mixed shale sedimentary environment restoration is used to: identify the changes in micro-region mineral composition and micro-region elements inside mixed shale through time-of-flight secondary ion mass spectrometry TOF-SIMS, and use biomarker compounds in organic geochemistry to identify the sedimentary environment changes corresponding to the complex facies changes of mixed shale, so as to clarify the formation mechanism of mixed shale.

[0079] An embodiment of the present invention also provides an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, a high-precision recovery method for determining a marine mixed-accumulation shale depositional environment as in the above-mentioned embodiment is implemented.

[0080] Fig.17 An example of a physical structure diagram of an electronic device is shown in FIG. Fig.17 As shown, the electronic device may include: a processor 210, a communication interface 220, a memory 230 and a communication bus 240, wherein the processor 210, the communication interface 220 and the memory 230 communicate with each other through the communication bus 240. The processor 210 may call the logic instructions in the memory 230 to execute a high-precision recovery method for determining the marine mixed shale deposition environment.

[0081] In addition, the logic instructions in the above-mentioned memory 230 can be implemented in the form of software functional units and can be stored in a computer-readable storage medium when sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0082] On the other hand, an embodiment of the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, a high-precision recovery method for determining a marine mixed shale depositional environment as in the above embodiment is implemented.

[0083] On the other hand, the present invention also provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can execute a high-precision recovery method for determining the marine mixed shale deposition environment provided by the above methods.

[0084] In summary, although the present invention has been disclosed as above in terms of preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A high-precision restoration method for determining the sedimentary environment of marine mixed shale. It is characterized in that The following steps are involved: Step S1, using XRD to preliminarily identify the marine mixed shale lithofacies, and analyzing the vertical distribution law of the marine mixed shale; using the total organic carbon TOC test to identify the abundance of organic matter in each lithofacies of the marine mixed shale; using XRD to analyze its mineral composition, and using the three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation to identify the main lithofacies types of the mixed shale, and judging the general sedimentary environment evolution trend based on the mineral content; judging and identifying the planar distribution characteristics of various lithofacies of the mixed shale based on the selection of cores from multiple wells; Step S2, using time-of-flight secondary ion mass spectrometry TOF-SIMS to identify the changes in micro-region mineral composition and micro-region elements within the mixed shale, and using biomarker compounds in organic geochemistry to identify the sedimentary environment changes corresponding to the complex facies changes of the mixed shale, so as to clarify the formation mechanism of the mixed shale.

2. According to claim 1, a high-precision recovery method for determining the sedimentary environment of marine mixed shale, It is characterized in that Step S1 also includes: cathode luminescence as a means of identifying terrigenous inputs. Different minerals will show different colors and spectral characteristics under cathode luminescence, which is helpful to identify the mineral type and its distribution; taking quartz as a landmark mineral, under cathode luminescence, terrigenous detrital quartz has strong luminescence phenomenon, while micron-level biogenic quartz has no luminescence phenomenon.

3. According to claim 1, a high-precision recovery method for determining the sedimentary environment of marine mixed shale, It is characterized in that Step S2 specifically includes: Step S21, using biomarker compounds to restore the overall change trend of its sedimentary environment, and using different types of mixed shale facies saturated hydrocarbon chromatography and mass spectrometry to determine the differences in organic matter sources and environmental changes.

4. A high-precision recovery method for determining the sedimentary environment of marine mixed shale according to claim 3, It is characterized in that Step S21 specifically includes: the first step is to obtain the results of chromatographic and mass spectrometric analysis of shale saturated hydrocarbons, and use the carbon number set index range in the analysis results to determine whether the organic matter belongs to the terrestrial phase or the marine phase; the second step is to use the pristane Pr / C17 and phytane Ph / C18 in the biomarker compounds for preliminary environmental identification, and use Pr / Ph for preliminary identification of reducibility; when the pristane-phytane ratio Pr / Ph is less than 0.5, it reflects a strongly reducing environment, when Pr / Ph is between 0.5 and 2, it is a reducing environment, and when Pr / Ph is greater than 2, it is characterized by terrestrial organic matter input in an oxidizing environment, and using Pr / nC18 to identify the terrestrial organic matter input in an oxidizing environment. 7 and Ph / nC18 ratio to identify the specific source of organic matter; the third step, in the mass spectrum, two mass-to-charge ratio conditions are selected for analysis, namely m / z=217 and m / z=191. In the mass spectrum analysis results of saturated hydrocarbons at m / z=217, the sterane composition and distribution characteristics can well reveal the source rock evolution process and sedimentary environment. The source of C27R sterane is mainly lower aquatic organisms of algae organisms, C28R sterane is mainly terrestrial higher plants, and C29R sterane is mainly related to blue-green algae; the distribution characteristics of the three steranes can intuitively judge the source of organic matter, thereby determining the sedimentary environment.

5. A high-precision recovery method for determining the sedimentary environment of marine mixed shale according to claim 4, It is characterized in that Step S2 specifically also includes: Step S22, determining the multi-dimensional coupling recovery mechanism of the marine mixed shale sedimentary environment, using TOF-SIMS to conduct micro-area testing of trace elements in the sample, and performing high-precision restoration of the sedimentary environment changes represented by the test point.

6. A high-precision recovery method for determining the sedimentary environment of marine mixed shale according to claim 5, It is characterized in that Step S22 specifically includes: The main and trace element values ​​identified by TOF-SIMS are used to study the redox properties of water bodies. Before using trace element substitute indicators to indicate the sedimentary environment, the trace elements are usually corrected using Ti elements to calculate non-detrital or excess elements and obtain corresponding excess values, thereby eliminating the interference of terrigenous materials. The variation patterns of the ratios of U / Th, Ni / Co, V / Cr, and V / (V+Ni) in the elements and the enrichment levels of V, Ni, Mo, and U are used for discrimination, where U represents uranium, V represents vanadium, Ni represents nickel, Mo represents molybdenum, Co represents cobalt, and Cr represents chromium; The CIA index, which indicates weathering intensity, is used as a paleoclimate identification mark. When the climate is humid, chemical weathering will be enhanced. Relevant indicators are used to restore the ecological level during the sedimentation period. P / Ti is used as a positive correlation indicator of ancient marine primary productivity to restore the ecological level as a verification indicator of sedimentary water changes. Organic matter carbon isotopes and nitrogen isotopes are used as identification indicators, where P represents phosphorus and Ti represents titanium.

7. A high-precision recovery system for determining the sedimentary environment of marine mixed shale. It is characterized in that It includes a system for identifying the lithofacies characteristics of mixed-depositional shale and a system for identifying the sedimentary environment restoration of mixed-depositional shale; The system for identifying the lithofacies characteristics of mixed shale is used to: use XRD to preliminarily identify the lithofacies of marine mixed shale, and analyze the vertical distribution law of marine mixed shale; use the total organic carbon TOC test to identify the organic matter abundance of each lithofacies of marine mixed shale; use XRD to analyze its mineral composition, and use the three main end members of carbonate minerals, clay minerals, and siliceous minerals to perform triangulation to identify the main lithofacies types of mixed shale, and judge the general sedimentary environment evolution trend according to the mineral content; based on the selection of multiple well cores, judge and identify the planar distribution characteristics of various lithofacies of mixed shale; The system for identifying mixed shale sedimentary environment restoration is used to: identify the changes in micro-region mineral composition and micro-region elements inside mixed shale through time-of-flight secondary ion mass spectrometry TOF-SIMS, and use biomarker compounds in organic geochemistry to identify the sedimentary environment changes corresponding to the complex facies changes of mixed shale, so as to clarify the formation mechanism of mixed shale.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, It is characterized in that When the processor executes the program, a high-precision recovery method for determining a marine mixed shale depositional environment as described in any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, It is characterized in that When the computer program is executed by a processor, a high-precision recovery method for determining a marine mixed shale depositional environment as described in any one of claims 1 to 6 is implemented.

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