Geochemical method for sediment source evolution analysis and paleoenvironment reconstruction

Abstract

The invention provides a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction, and relates to the technical field of geochemistry, and the geochemical method comprises the following steps: carrying out component separation treatment on a core sample to obtain an authigenic carbonate component and a terrestrial source debris component; respectively carrying out element content test and Sr isotope ratio test on the authigenic carbonate component and the terrestrial debris component; based on the element content test result of the terrestrial source detritus component and the Sr isotope ratio test result, analyzing to obtain a sediment source evolution result; and based on the element content test result of the authigenic carbonate component and the Sr isotope ratio test result, analyzing to obtain a sedimentary paleoenvironment evolution result and a recording result of paleowater element geochemical information. According to the method, the sedimentary paleoenvironment reconstruction and the material source evolution analysis can be carried out through the authigenic carbonate component and the terrestrial source clastic component in the non-pure carbonate rock sedimentary region, and a new thought is provided for the sedimentary paleoenvironment reconstruction and the material source evolution analysis of the oil-gas-containing sedimentary basin.

Description

Technical Field

[0001] The present invention relates to the field of geochemistry technology, and is applied to the analysis of sediment provenance evolution and paleo - environment reconstruction. Specifically, it relates to a geochemical method for sediment provenance evolution analysis and paleo - environment reconstruction. Background Art

[0002] Sediment provenance tracing (analysis) and sedimentary paleo - environment restoration are the basis of sedimentary basin analysis, which can provide important scientific basis for the development and evolution of the basin and sedimentary filling. At the same time, they are also the most basic work in regional stratigraphic correlation and hydrocarbon reservoir prediction, and are of great significance in hydrocarbon resource exploration. Provenance analysis mainly answers three questions: where the sediment comes from (geographical location), what kind of geological body the sediment comes from (rock type), and the transportation route of the sediment (sedimentary dynamics and its influencing factors).

[0003] Although marine sediments are complex and variable, they mainly include two parts: terrigenous and authigenic (biological and chemical) sediments. For terrigenous materials, it is necessary to know where the sediment comes from and the deposition mode, and for authigenic sediments, it is necessary to know the reflected sedimentary environment.

[0004] There are many geochemical methods for sediment provenance analysis, and there are still many indicators and methods for provenance discrimination being explored and improved. Each method has its own applicable object and scientific problem to solve. At present, there is no perfect and comprehensive geochemical method for analyzing sediment provenance using geochemical indicators. Therefore, the applicability of various methods should be fully considered when analyzing sediment provenance using geochemical indicators.

[0005] The geochemical characteristics of ancient water bodies are of great significance for sedimentary paleo - environment reconstruction. Existing research has shown that pure carbonate rocks such as carbonate platforms and reef biogenic carbonates have always been considered good carriers for recording the geochemical information of ancient water bodies, and their geochemical characteristics can be used to reflect the geochemical characteristics of ancient water bodies. However, in areas lacking pure carbonate rocks, it is very difficult to extract the geochemical information of ancient water bodies.

[0006] Aiming at the problems of the existing technology, the present invention provides a geochemical method for sediment provenance evolution analysis and paleo - environment reconstruction. Summary of the Invention

[0007] Aiming at the problems of the current existing technology, the present invention provides a geochemical method for sediment provenance evolution analysis and paleo - environment reconstruction, and the method includes:

[0008] Performing component separation treatment on the core samples to obtain authigenic carbonate components and terrigenous clastic components;

[0009] Element content tests and Sr isotope ratio tests are respectively carried out on the authigenic carbonate component and the terrigenous clastic component;

[0010] Based on the element content test results and Sr isotope ratio test results of the terrigenous clastic component, the sediment source evolution result is analyzed;

[0011] Based on the element content test results and Sr isotope ratio test results of the authigenic carbonate component, the sedimentary paleo - environment evolution result and the recording result of the paleo - water body element geochemical information are analyzed.

[0012] According to an embodiment of the present invention, the core sample is obtained through the following steps:

[0013] Coring is carried out on a well that meets the requirements of drilling depth, continuous age, and preservation of core sediments to obtain a core sample to be processed;

[0014] The core sample to be processed is subjected to oil washing treatment to obtain the core sample.

[0015] According to an embodiment of the present invention, the authigenic carbonate component is obtained through the following steps:

[0016] The powder after grinding the core sample is placed in a container, acetic acid solution is added, and after the powder is completely dissolved, it is centrifuged and the supernatant is taken as the authigenic carbonate component.

[0017] According to an embodiment of the present invention, the terrigenous clastic component is obtained through the following steps:

[0018] Hydrofluoric acid, nitric acid, and perchloric acid are added to the sample after extracting the supernatant, and after heating until completely dissolved, the hydrofluoric acid and perchloric acid in the solution are driven off, and then nitric acid is added for back - dissolution to be used as the terrigenous clastic component.

[0019] According to an embodiment of the present invention, the element content test is carried out through the following steps:

[0020] A constant - element test is carried out using an inductively coupled plasma atomic emission spectrometer;

[0021] A trace - element test and a rare - earth element test are carried out using an inductively coupled plasma mass spectrometer;

[0022] The Sr isotope ratio test is carried out through the following steps:

[0023] The Sr isotope ratio test is carried out using a multi - collector inductively coupled plasma mass spectrometer.

[0024] According to an embodiment of the present invention, the sediment source evolution result is analyzed through the following steps:

[0025] Based on the test results of the elemental contents of the terrigenous clastic components, determine the Al content, Th content, and light-to-heavy rare earth ratio;

[0026] Based on the test results of the Sr isotope ratio of the terrigenous clastic components, determine the 87 Sr / 86 Sr ratio of the terrigenous clastic components;

[0027] Integrate the Al content, Th content, light-to-heavy rare earth ratio, 87 Sr / 86 Sr ratio of the terrigenous clastic components to obtain the variation of the input of ancient terrigenous clastics;

[0028] Based on the test results of the elemental contents of the terrigenous clastic components, obtain the REE distribution pattern results of the terrigenous clastic components to determine the sediment source results.

[0029] According to an embodiment of the present invention, the above recording results are obtained through the following steps of analysis:

[0030] Based on the test results of the elemental contents of the authigenic carbonate components, determine the variation relationship of the Ca, Mg, Sr, and Mn contents to obtain the influence results of dolomitization on the geochemical characteristics of the authigenic carbonate components;

[0031] Based on the test results of the elemental contents of the authigenic carbonate components, obtain the REE distribution pattern results of the authigenic carbonate components to determine the REE geochemical information of the ancient water body.

[0032] According to an embodiment of the present invention, the above sedimentary paleoenvironment evolution results are obtained through the following steps of analysis:

[0033] Based on the test results of the Sr isotope ratio of the authigenic carbonate components, determine the 87 Sr / 86 Sr ratio of the authigenic carbonate components to obtain the variation of the terrigenous Sr input.

[0034] According to another aspect of the present invention, there is also provided a storage medium, which contains a series of instructions for executing the method steps described in any one of the above.

[0035] According to another aspect of the present invention, there is also provided a geochemical method device for sediment source evolution analysis and paleoenvironment reconstruction, which executes a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction described in any one of the above. The device includes:

[0036] A component module, which is used to perform component separation processing on the core sample to obtain authigenic carbonate components and terrigenous clastic components;

[0037] A test module for separately performing element content tests and Sr isotope ratio tests on the authigenic carbonate component and the terrigenous clastic component;

[0038] A provenance analysis module for obtaining a sediment provenance evolution result based on the element content test result and Sr isotope ratio test result of the terrigenous clastic component;

[0039] A paleoenvironment reconstruction module for obtaining a sedimentary paleoenvironment evolution result and a record result of paleo - water body element geochemical information based on the element content test result and Sr isotope ratio test result of the authigenic carbonate component.

[0040] The present invention provides a geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction. Compared with the prior art, it has the following advantages:

[0041] 1) The method provided by the present invention proves that the grouped - component (authigenic carbonate component and terrigenous clastic component) analysis can effectively extract geochemical indicators in the drilling core that can reflect sediment provenance, paleoenvironment, and paleo - seawater chemical composition;

[0042] 2) The present invention proves that the rare earth elements (REE) of the carbonate component in clastic sediments are affected by the terrigenous clastic component to a certain extent and do not necessarily truly reflect the REE geochemical characteristics of the paleo - water body;

[0043] 3) The present invention gives a method for obtaining the change curve of the Sr isotope composition of the paleo - water body based on the sedimentary carbonate component, indicating that the Sr isotope composition has guiding significance in both sedimentary paleoenvironment reconstruction and provenance analysis;

[0044] 4) The present invention can perform sedimentary paleoenvironment reconstruction and provenance evolution analysis through the authigenic carbonate component and terrigenous clastic component separated from clastic sediments in non - pure carbonate rock sedimentary areas, providing new ideas for basic research such as sedimentary paleoenvironment reconstruction and provenance evolution analysis in oil - and - gas - bearing sedimentary basins (mostly dominated by clastic rocks).

[0045] Other features and advantages of the present invention will be described in the subsequent specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures specifically pointed out in the specification, claims, and drawings. Description of the Drawings

[0046] The drawings are used to provide further understanding of the present invention, and constitute a part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0047] Figure 1 Shows a flowchart of the steps of a geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to an embodiment of the present invention;

[0048] Figure 2 Shows a schematic diagram of the process of a geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to an embodiment of the present invention;

[0049] Figure 3 Shows a schematic diagram of the sampling horizons of core samples according to an embodiment of the present invention;

[0050] Figure 4 Shows the 87 Sr / 86 Sr ratio (a), Al2O3 content (b), Th content (c), and LREE / HREE ratio (d) variation curve comparison diagrams of terrigenous clastic components in drilling core samples according to an embodiment of the present invention;

[0051] Figure 5 Shows the PAAS-normalized REE partition pattern of terrigenous clastic components in drilling core samples according to an embodiment of the present invention;

[0052] Figure 6 Shows a well location map of drilling wells in the Ying-Qiong Basin according to an embodiment of the present invention;

[0053] Figure 7 Shows the variation curves of the Ca, Mg, Sr, Mn contents and Mn / Sr ratio of authigenic carbonate components with depth in drilling core samples according to an embodiment of the present invention;

[0054] Figure 8 Shows the covariation diagram of the Mg / Ca ratio of authigenic carbonate components with the Ca, Mg, Mn, Sr contents;

[0055] Figure 9 Shows the PAAS-normalized REE partition patterns of authigenic carbonate components, reef carbonates, ocean seawater, and marine ferromanganese oxides in drilling core samples according to an embodiment of the present invention;

[0056] Figure 10 Shows a comprehensive analysis diagram of the evolution process of the sedimentary paleoenvironment in a sedimentary basin according to an embodiment of the present invention.

[0057] In the drawings, the same components are denoted by the same reference numerals. Additionally, the drawings are not drawn to actual scale. Detailed Embodiments

[0058] To make the objectives, technical solutions, and advantages of the present invention more clear, the following further describes the embodiments of the present invention in detail with reference to the accompanying drawings.

[0059] The Earth is composed of chemical elements. During the formation of macroscopic geological bodies through various geological processes in the Earth system, there is always a redistribution process of elements. Therefore, the geochemical characteristics of elements record the time (isotopes), process (changes in element content and characteristic ratios), and results (element enrichment and depletion) of geological processes. Therefore, geochemical characteristics are the "fingerprints" of geological processes. Different sediment types have different element compositions, which is the basis for provenance tracing and paleoenvironment restoration.

[0060] Although various modifications and element exchanges occur during the weathering and transportation of sediments, terrigenous clastic sediments generally still inherit the properties of the source area, especially components that are relatively immobile during weathering, transportation, and diagenesis (such as elements like REE and Al, Th, Sc, Zr, etc.). This provides a basis for provenance discrimination. Major components are mainly used to determine the main rock types and tectonic backgrounds of the source area, and some indicators can indicate the environment. Trace and rare earth elements are mainly used for determining the source area and tectonic background of fine-grained sediments because some of these elements (such as elements like Al, Th, Sc, Zr, and Y) show extremely strong inertness during weathering and transportation and are easily adsorbed by colloidal ions and quickly enter fine-grained sediments. The REE distribution pattern basically does not change significantly from the source area to the sedimentary area. The ratios of REE and certain trace elements are also relatively inert (stable) during sedimentation and metamorphism processes. Therefore, the above elements in sediments are good indicators of the geochemical characteristics of the parent rock. Clastic sediments derived from different tectonic environments have different trace element contents and ratio characteristics and are widely used for discriminating the tectonic environment of the provenance area of sedimentary basins.

[0061] Currently, the extraction of paleo-water body geochemical information and the reconstruction of sedimentary paleoenvironments are mainly based on pure carbonate rock samples. Such samples are basically formed in the paleo-water body and are representative. However, in many areas, they are clastic sediments with a relatively low carbonate component content. Therefore, in areas lacking pure carbonate rocks, it is very difficult to extract paleo-water body geochemical information, and the geochemical methods for provenance analysis of clastic sediments and reconstruction of sedimentary paleoenvironments need to be further deepened.

[0062] The prior art (CN114112563A) provides a thin slice of loose sandy sediment, a manufacturing method thereof and an application. The prior art (CN114839690A) relates to a method, a device, a medium and equipment for determining the organic carbon content of a hydrocarbon source rock. The prior art (CN116228453A) discloses a method, a system, equipment and a terminal for evaluating control factors of shale organic matter enrichment. The prior art (CN102608235A) discloses a method for analyzing biomarkers in natural gas. The prior art (CN114220490A) discloses a method and a device for correcting the Sr element content in sediment. The prior art (Wang Ke, Zhai Shikui. 2020. Geochemical methods for sediment provenance discrimination. Marine Sciences, 44(12): 132-143, DOI: 10.11759 / hykx20191115001) discloses geochemical methods for sediment provenance discrimination. However, none of the above prior arts solve the technical problem that it is very difficult to extract paleo-water body geochemical information in areas lacking pure carbonate rocks.

[0063] The prior art (Wang Ke, Zhai Shikui, Yu Zenghui, Zhang Huaijing. 2023. Geochemical characteristics of Sr isotopes in the LS33 drillcore from the Qiongdongnan Basin, South China Sea, and their response to the uplift of the Tibetan Plateau. Acta Oceanologica Sinica, 42(5): 117–129, DOI: 10.1007 / s13131-022-2069-2) discloses the geochemical characteristics of Sr isotopes in drillcores and their response to the uplift of the Tibetan Plateau. Although it mentions using parameters such as Sr isotopes in drillcores to reveal the geochemical characteristics of paleo-seawater, it does not involve the indication of sediment provenance and paleo-environment by major elements, trace elements and rare earth elements. The present invention innovatively takes into account the testing of major elements, trace elements and rare earth elements. It can be verified through the present invention that major elements, trace elements and rare earth elements can supplement important geochemical evidence for provenance analysis and paleo-environment reconstruction, and can also verify the effectiveness and accuracy of Sr isotope analysis results.

[0064] Aiming at the above defects of the prior art, on the basis of making full use of modern analytical testing technologies, the present invention explores and establishes new indicators or methods for extracting paleo-water body geochemical information from sediments, so as to realize the comprehensive determination of sediment provenance and paleo-environment based on clastic sediments.

[0065] Figure 1 Shows a step - flow chart of a geochemical method for sediment source evolution analysis and paleo - environment reconstruction according to an embodiment of the present invention.

[0066] As Figure 1 shown, in step S101, the core sample is subjected to component separation treatment to obtain authigenic carbonate components and terrigenous clastic components.

[0067] In one embodiment, in step S101, the core sample is obtained through the following steps: select a well that meets the requirements of drilling depth, continuous age, and preservation of core sediments for coring to obtain a core sample to be processed; perform oil - washing treatment on the core sample to be processed to obtain the core sample, as Figure 2 shown.

[0068] Specifically, select a well with a large drilling depth, continuous age, and well - preserved core sediments for coring. Such wells have more advantages in sediment source and paleo - environment analysis compared to other wells. In principle, equidistant sampling is carried out, with more samples taken in the intervals with large lithological changes and fewer samples taken in the intervals with small lithological changes, as Figure 3 shown. It should be noted that the requirements for drilling depth, continuous age, and core sediments can be selected by those skilled in the art according to needs, and the present invention does not limit this.

[0069] Furthermore, the "organic distillation extraction method" is used for oil - washing. Specifically, the oil - washing instrument is a Soxhlet extractor, and the organic reagents used for oil - washing are 75 ml of absolute ethanol (mass fraction ≥ 99.7%, density 0.789 - 0.791 g / cm 3 ) and 75 ml of carbon tetrachloride (mass fraction ≥ 99.5%, density 1.592 - 1.598 g / cm 3 ), and the cleaning time is 20.5 h to completely remove the oil base.

[0070] In one embodiment, in step S101, the core sample is subjected to component separation, and the authigenic carbonate components are obtained through the following steps: place the powder obtained by grinding the core sample in a container, add acetic acid solution, and after the powder is completely dissolved, centrifuge and take the supernatant as the authigenic carbonate components.

[0071] Specifically, the core sample must be dried at a constant temperature of 60 °C for 12 h and ground to less than 200 mesh to enable it to dissolve fully; weigh 200 mg of sample powder and place it in a clean Teflon digestion vessel, add acetic acid solution with a volume fraction of 10%, and after the carbonate is completely dissolved, centrifuge and take the supernatant for use in analyzing the authigenic carbonate components.

[0072] In one embodiment, in step S101, the core sample is subjected to component separation, and the terrigenous clastic component is obtained through the following steps: Hydrofluoric acid, nitric acid, and perchloric acid are added to the sample after extracting the supernatant, and then heated until completely dissolved. After that, the hydrofluoric acid and perchloric acid in the solution are driven off, and then nitric acid is added for back-dissolution to serve as the terrigenous clastic component.

[0073] Specifically, the core sample must be dried at a constant temperature of 60 °C for 12 h and ground to less than 200 mesh to enable sufficient dissolution; 1.5 mL of hydrofluoric acid, 1.5 mL of nitric acid, and 0.2 mL of perchloric acid are added to the residue after extracting the supernatant, and heated on a hot plate for 36 h until the sample is completely dissolved. Then, the sample is evaporated to near dryness at 180 °C to drive off the hydrofluoric acid and perchloric acid in the solution. Finally, nitric acid (2%) is added for back-dissolution for use in the analysis of terrigenous clastic components.

[0074] In one embodiment, in step S101, the component separation of the core sample further includes: purifying the Sr isotope using AG50W×12 cation exchange resin (the ratio of hydrochloric acid to the regenerated resin column is 1:1), sucking the sample supernatant and adding it to the exchange column, washing with hydrochloric acid (2.5 N) and receiving Sr, and finally heating and evaporating the Sr receiving solution to dryness on a hot plate, and purifying it one more time according to this process.

[0075] As Figure 1 shown, in step S102, the elemental content tests and Sr isotope ratio tests are respectively carried out on the authigenic carbonate component and the terrigenous clastic component.

[0076] In one embodiment, in step S102, the major elements, trace elements, rare earth element contents, and Sr isotope ratios of the authigenic carbonate component and the terrigenous clastic component are respectively tested. Among them, the elemental content tests are carried out through the following steps: an inductively coupled plasma atomic emission spectrometer is used for major element tests; an inductively coupled plasma mass spectrometer is used for trace element tests and rare earth element tests.

[0077] In one embodiment, in step S102, the Sr isotope ratio test is carried out through the following steps: a multi-receiver inductively coupled plasma mass spectrometer is used for Sr isotope ratio tests.

[0078] Specifically, as Figure 2As shown, the determination of major elements was performed using an inductively coupled plasma atomic emission spectrometer (ICP-AES), and the determination of trace elements and rare earth elements was performed using an inductively coupled plasma mass spectrometer (ICP-MS). The reference materials were GBW07309. The Sr isotope composition analysis was performed using a multi-collector inductively coupled plasma mass spectrometer (Nu Plasma HR-MC-ICP-MS), and the reference materials were GBW04411 and NBS987.

[0079] As Figure 1 shown, in step S103, based on the test results of the elemental contents and Sr isotope ratios of terrigenous clastic components, the sediment provenance evolution results were analyzed.

[0080] In one embodiment, in step S103, the sediment provenance evolution results were analyzed through the following steps: According to the test results of the elemental contents of terrigenous clastic components, the Al content, Th content, and light / heavy rare earth ratio were determined; according to the test results of the Sr isotope ratios of terrigenous clastic components, the 87 Sr / 86 Sr ratio of terrigenous clastic components was determined; by integrating the Al content, Th content, light / heavy rare earth ratio, 87 Sr / 86 Sr ratio of terrigenous clastic components, the variation of ancient terrigenous clastic input was obtained; based on the test results of the elemental contents of terrigenous clastic components, the REE distribution pattern results of terrigenous clastic components were obtained to determine the sediment source results.

[0081] Specifically, as Figure 2 shown, the elemental and Sr isotope geochemical characteristics of terrigenous clastic components were used to discuss the sediment provenance evolution. Further, the Al, Th, light / heavy rare earth ratio (LREE / HREE), and 87 Sr / 86 Sr ratio were used to reflect the variation of ancient terrigenous clastic input. An increase in the above contents or ratios represents an increase in ancient terrigenous clastic input. As Figure 4 shown, Figure 4 the vertical dotted lines in represent the average values of each layer section.

[0082] Specifically, as Figure 2 shown, the REE distribution pattern of terrigenous clastic components was used to reflect the source of clastic sediment. Further, the more similar the REE distribution patterns are, the more consistent the regional provenance is. As Figure 5 and Figure 6 shown, Figure 5 the data in Figure 6 came from Well LS33 in the Yingqiong Basin. Figure 5Among them, curve a represents the Ledong Formation of the Quaternary, curve b represents the Huangliu Formation of the late Miocene, curve c represents the Yinggehai Formation of the Pliocene, curve d represents the Sanya Formation of the early Miocene, curve e represents the Meishan Formation of the middle Miocene, curve f represents the Yacheng Formation of the early Oligocene, and curve g represents the Lingshui Formation of the late Oligocene.

[0083] As Figure 1 shown, in step S104, based on the test results of the element content and Sr isotope ratio of the authigenic carbonate component, the evolution result of the sedimentary paleoenvironment and the recording result of the paleo-water body element geochemical information are analyzed.

[0084] In one embodiment, in step S104, the recording result is analyzed through the following steps: according to the test results of the element content of the authigenic carbonate component, the variation relationship of Ca, Mg, Sr, and Mn contents is determined to obtain the influence result of dolomitization on the geochemical characteristics of the authigenic carbonate component; based on the test results of the element content of the authigenic carbonate component, the REE distribution pattern result of the authigenic carbonate component is obtained to determine the REE geochemical information of the paleo-water body.

[0085] Specifically, as Figure 2 shown, the element geochemical characteristics of the authigenic carbonate component are used to reflect the degree of transformation of the diagenesis on the element geochemical characteristics of the authigenic carbonate component. Further, the variation relationship of Ca, Mg, Sr, and Mn contents is used to reveal the influence of dolomitization on the authigenic carbonate component. There is an obvious negative correlation between the contents of the characteristic elements Ca and Mg of the authigenic carbonate component and the well depth. This variation trend is mainly the manifestation of the isomorphic substitution relationship between Mg and Ca, and to a certain extent, it also reflects the strength change of dolomitization, as Figure 7 shown; by analyzing the relationship between the Mg / Ca ratio and the variation of Ca, Mg, Sr, and Mn contents, the influence of dolomitization on the element geochemical characteristics of the authigenic carbonate component can be revealed. The stronger the correlation, the greater the influence, as Figure 8 shown.

[0086] Specifically, as Figure 2 shown, the REE distribution pattern of the authigenic carbonate component is used to judge whether the authigenic carbonate component carries the effective REE geochemical information of the paleo-water body. Further, taking marine carbonate as an example, its REE distribution pattern is compared with that of ocean seawater or reef carbonate rocks, especially paying attention to the Ce anomaly and the total rare earth element characteristics. If the above two characteristics do not match, the authigenic carbonate component does not carry the effective REE geochemical information of the paleo-water body, as Figure 9 shown, the similarity between the REE geochemical characteristics of the authigenic carbonate component and those of marine iron-manganese oxides indicates that the former may be affected by iron-manganese oxides in sediments. Figure 9Among them, curve a represents the Ledong Formation of the Quaternary, curve b represents the Huangliu Formation of the late Miocene, curve c represents the Yinggehai Formation of the Pliocene, curve d represents the Sanya Formation of the early Miocene, curve e represents the Meishan Formation of the middle Miocene, curve f represents the Yacheng Formation of the early Oligocene, curve g represents the Lingshui Formation of the late Oligocene, curve h represents the reef carbonates of Well Xike 1, curve i represents ocean water, curve j represents hydrogenetic ferromanganese oxide crusts, and curve k represents diagenetic ferromanganese oxide nodules.

[0087] In one embodiment, in step S104, the results of the evolution of the sedimentary paleoenvironment are obtained through the following steps: Based on the test results of the Sr isotope ratios of the authigenic carbonate components, the 87 Sr / 86 Sr ratio of the authigenic carbonate components is determined to obtain the variation of terrigenous Sr input.

[0088] Specifically, as Figure 2 shown, the Sr isotope ratios of the authigenic carbonate components are used to discuss the evolution of the sedimentary paleoenvironment. Further, the 87 Sr / 86 Sr ratio of the authigenic carbonate components represents the 87 Sr / 86 Sr ratio of the ancient water body, and its variation can reflect the variation of terrigenous Sr input. When the 87 Sr / 86 Sr ratio increases, it indicates an increase in the terrigenous Sr input; when the grain size becomes finer, the pyrite content increases, and the microfossils are mainly non-benthic organisms, it indicates an increase in water depth and a decrease in terrigenous material input, which can be used to corroborate the 87 Sr / 86 Sr ratio analysis results, as Figure 10 shown.

[0089] The present invention believes that the carbonate components theoretically also have research value for reconstructing the sedimentary paleoenvironment. Based on the above situation, the present invention makes full use of modern analytical testing technologies. Exploring and establishing new indicators or methods for extracting the geochemical information of ancient water bodies in sediments will contribute to reconstructing the sedimentary paleoenvironment of different research areas. The present invention divides the clastic sediments into carbonate components and terrigenous clastic components. The former is used for the research of sedimentary paleoenvironment reconstruction methods, and the latter is used for the research of provenance analysis methods, realizing the comprehensive determination of provenance and paleoenvironment based on clastic sediments.

[0090] A geochemical method for sediment source evolution analysis and paleoenvironment reconstruction provided by the present invention can also cooperate with a computer-readable storage medium. A computer program is stored on the storage medium, and the computer program is executed to run a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction. The computer program can run computer instructions, and the computer instructions include computer program code, and the computer program code can be in the form of source code, object code, executable file or some intermediate form, etc.

[0091] The computer-readable storage medium can include: any entity or device capable of carrying computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disc, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal, and software distribution medium, etc.

[0092] It should be noted that the content included in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice within the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electrical carrier signals and telecommunication signals.

[0093] According to another aspect of the present invention, a geochemical device for sediment source evolution analysis and paleoenvironment reconstruction is also provided, which executes a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction. The device includes: a component module, a testing module, a provenance analysis module, and a paleoenvironment reconstruction module.

[0094] The component module is used for performing component separation processing on the core sample to obtain authigenic carbonate components and terrigenous clastic components; the testing module is used for respectively performing element content testing and Sr isotope ratio testing on the authigenic carbonate components and terrigenous clastic components; the provenance analysis module is used for analyzing and obtaining sediment source evolution results based on the element content testing results and Sr isotope ratio testing results of the terrigenous clastic components; the paleoenvironment reconstruction module is used for analyzing and obtaining sedimentary paleoenvironment evolution results and recording results of paleo-water body element geochemical information based on the element content testing results and Sr isotope ratio testing results of the authigenic carbonate components.

[0095] In summary, the present invention provides a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction. Compared with the prior art, it has the following advantages:

[0096] 1) The method provided by the present invention proves that the analysis of grouped components (authigenic carbonate components and terrigenous clastic components) can effectively extract geochemical indicators contained in the drilling core that can reflect sediment source, paleoenvironment, and paleo-seawater chemical composition;

[0097] 2) The present invention proves that the rare earth elements (REE) of the carbonate component in detrital sediments are affected to a certain extent by terrigenous detrital components and do not necessarily truly reflect the REE geochemical characteristics of the ancient water body;

[0098] 3) The present invention provides a method for obtaining the variation curve of the Sr isotope composition of the ancient water body based on the sedimentary carbonate component, indicating that the Sr isotope composition is significant in both sedimentary paleoenvironment reconstruction and provenance analysis;

[0099] 4) The present invention can reconstruct the sedimentary paleoenvironment and analyze the provenance evolution through the authigenic carbonate component and terrigenous detrital component separated from detrital sediments in non-pure carbonate rock sedimentary areas, providing new ideas for basic research such as sedimentary paleoenvironment reconstruction and provenance evolution analysis in oil and gas-bearing sedimentary basins (mostly dominated by clastic rocks).

[0100] It should be understood that the embodiments disclosed in the present invention are not limited to the specific structures, processing steps or materials disclosed herein, but should extend to equivalent alternatives of these features understood by those of ordinary skill in the relevant fields. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and do not imply limitation.

[0101] In the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientation or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0102] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0103] Certain terms are used throughout this application document to refer to specific system components. As those skilled in the art will recognize, the same components can typically be referred to by different names, and thus this application document does not intend to distinguish components that differ only in name but not in function. In this application document, the terms "comprise," "include," and "have" are used in an open-ended fashion and should thus be interpreted to mean "including but not limited to...". Additionally, the terms "substantially," "essentially," or "approximately" as may be used herein refer to the industry-accepted tolerances for the corresponding terms. The term "coupled" as may be used herein includes direct coupling and indirect coupling via additional components, elements, circuits, or modules, where for indirect coupling, the intervening components, elements, circuits, or modules do not change the information of the signal but may adjust its current level, voltage level, and / or power level. Inferred coupling (e.g., where one element is coupled to another element by inference) includes direct and indirect coupling between the two elements in the same manner as "coupled".

[0104] As used in the specification, the phrase "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "one embodiment" or "an embodiment" throughout the specification are not necessarily all referring to the same embodiment.

[0105] Embodiments of the present invention are given by way of example and description, and are not exhaustive or limit the present invention to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles of the present invention and its practical applications, and to enable those of ordinary skill in the art to understand the present invention so as to design various embodiments with various modifications suitable for a particular purpose.

[0106] Although the embodiments disclosed in the present invention are as above, the content described is only an embodiment adopted for the convenience of understanding the present invention and is not intended to limit the present invention. Any person skilled in the art within the technical field to which the present invention pertains, without departing from the spirit and scope disclosed by the present invention, may make any modifications and changes in the form of implementation and details, but the scope of patent protection of the present invention shall still be subject to the scope defined by the appended claims.

Claims

1. A geochemical method for sediment source evolution analysis and paleoenvironment reconstruction, characterized in that, The method includes: Performing component separation treatment on the core sample to obtain authigenic carbonate components and terrigenous clastic components; Respectively performing elemental content testing and Sr isotope ratio testing on the authigenic carbonate components and the terrigenous clastic components; Based on the elemental content testing results and Sr isotope ratio testing results of the terrigenous clastic components, analyzing and obtaining the sediment source evolution results; Based on the elemental content testing results and Sr isotope ratio testing results of the authigenic carbonate components, analyzing and obtaining the sedimentary paleoenvironment evolution results and the recording results of the elemental geochemical information of the ancient water body.

2. The geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to claim 1, wherein The core sample is obtained through the following steps: Selecting a well that meets the requirements of drilling depth, continuous age, and preservation of core sediments for coring to obtain a core sample to be processed; Performing oil washing treatment on the core sample to be processed to obtain the core sample.

3. A geochemical method for sediment source evolution analysis and paleoenvironment reconstruction according to claim 1 or 2, characterized in that, The authigenic carbonate components are obtained through the following steps: Placing the powder obtained by grinding the core sample in a container, adding acetic acid solution, and after the powder is completely dissolved, centrifuging and taking the supernatant as the authigenic carbonate components.

4. A geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to claim 3, characterized in that, The terrigenous clastic components are obtained through the following steps: Adding hydrofluoric acid, nitric acid, and perchloric acid to the sample after extracting the supernatant, heating until completely dissolved, driving away the hydrofluoric acid and perchloric acid in the solution, and then adding nitric acid for back-dissolution to serve as the terrigenous clastic components.

5. A geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to any one of claims 1-4, characterized in that The elemental content testing is performed through the following steps: using an inductively coupled plasma atomic emission spectrometer for major element testing; using an inductively coupled plasma mass spectrometer for trace element testing and rare earth element testing; The Sr isotope ratio testing is performed through the following steps: using a multi-collector inductively coupled plasma mass spectrometer for the Sr isotope ratio testing.

6. A geochemical method for sediment provenance evolution analysis and paleoenvironment reconstruction according to any one of claims 1-5, characterized in that, The sediment source evolution results are analyzed and obtained through the following steps: Based on the elemental content testing results of the terrigenous clastic components, determining the Al content, Th content, and light and heavy rare earth ratio; Based on the test results of the Sr isotope ratio of the terrigenous clastic components, determine the 87 Sr / 86 Sr ratio; Based on the Al content, Th content, light and heavy rare earth element ratio, 87 Sr / 86 Sr ratio of terrigenous clastic components, the variation of ancient terrigenous clastic input is obtained; Based on the elemental content testing results of the terrigenous clastic components, obtaining the REE distribution pattern results of the terrigenous clastic components to determine the sediment source results.

7. A geochemical method for sediment source evolution analysis and paleoenvironment reconstruction according to any one of claims 1-6, characterized in that The recording results are analyzed and obtained through the following steps: Based on the elemental content testing results of the authigenic carbonate components, determining the change relationship of Ca, Mg, Sr, and Mn contents to obtain the influence results of dolomitization on the geochemical characteristics of the authigenic carbonate components; Based on the elemental content testing results of the authigenic carbonate components, obtaining the REE distribution pattern results of the authigenic carbonate components to determine the REE geochemical information of the ancient water body.

8. A geochemical method for sediment source evolution analysis and paleoenvironment reconstruction according to any one of claims 1-7, characterized in that, The sedimentary paleoenvironment evolution results are analyzed and obtained through the following steps: Based on the test results of the Sr isotope ratio of the authigenic carbonate component, determine the 87 Sr / 86 Sr ratio to obtain the variation of terrigenous Sr input.

9. A storage medium, characterized in that, It includes a series of instructions for executing the method steps described in any one of claims 1-8.

10. A geochemical device for sediment source evolution analysis and paleoenvironment reconstruction, characterized in that, Executing a geochemical method for sediment source evolution analysis and paleoenvironment reconstruction described in any one of claims 1-8, the device includes: A component module, which is used for performing component separation treatment on the core sample to obtain authigenic carbonate components and terrigenous clastic components; A test module, which is used to perform elemental content tests and Sr isotope ratio tests on the authigenic carbonate component and the terrigenous clastic component respectively; A provenance analysis module, which is used to analyze and obtain the sediment provenance evolution result based on the elemental content test result and Sr isotope ratio test result of the terrigenous clastic component; A paleoenvironment reconstruction module, which is used to analyze and obtain the sedimentary paleoenvironment evolution result and the recording result of the elemental geochemical information of the ancient water body based on the elemental content test result and Sr isotope ratio test result of the authigenic carbonate component.

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