Method and device for determining sedimentation rate of black shale in ancient lake

Abstract

The invention discloses a method and device for determining the deposition rate of black shale in an ancient lake, and the method comprises the steps: sampling a black shale section in a drilling core, and measuring the total organic carbon content, the total rare earth element amount and the total cobalt Co element amount in each sample; establishing a corresponding first correction relationship according to the total organic carbon content and the total Co element sum, and eliminating the Co element content brought by biological activity according to the first correction relationship to obtain a first Co element content; establishing a corresponding second correction relation according to the first Co element content and the total rare earth element amount, and eliminating the Co element content brought by material source input according to the second correction relation to obtain a second Co element content; processing the second Co element content according to the distribution characteristics of the Co element content data of the sample to obtain the Co element content from the cosmic dust in the shale; and determining the deposition rate of the black shale in the ancient lake according to the Co element content from the cosmic dust and the Co element deposition flux of the cosmic dust.

Description

Technical Field

[0001] The present invention relates to the technical field of basic research on petroleum geology, and in particular to a method and device for determining the deposition rate of black shale in ancient lakes. Background Art

[0002] Lacustrine black shale is not only the main source rock of conventional oil and gas reservoirs, but also an important reservoir for unconventional oil and gas reservoirs such as shale oil and shale gas. Organic matter in lakes is partially decomposed by heterotrophic microorganisms during the process of settling from the surface of the lake to the bottom of the lake and gradually buried, and only a small part of it is preserved in the shale. The faster the formation sedimentation rate, the shorter the time for organic matter to be oxidized and decomposed by microorganisms, which is more conducive to the enrichment of organic matter in shale. Therefore, accurately restoring the sedimentation rate of ancient lake black shale is crucial for studying the enrichment process of organic matter in shale and conducting evaluation of shale oil and gas exploration and development potential.

[0003] In some technologies, obtaining a high-resolution sedimentation rate of black shale in ancient lakes mainly depends on the comprehensive analysis of cyclostratigraphy. The comprehensive analysis method of cyclostratigraphy first requires accurate age anchor points at the top and bottom of the shale formation (to determine the sedimentation time limit of the shale), and assumes that the shale is deposited continuously. However, lake water bodies are greatly affected by seasonal alternation and climate change. The lake level often fluctuates over a large range and even dries up briefly (sedimentation interruption); and as the geological age of the formation becomes older, when 14 When C dating cannot be applied, the accuracy of U-Pb dating is difficult to meet the calculation of sedimentation rates in thinner strata (short sedimentation time).

[0004] Some technologies propose a method to calculate the lake sedimentation rate using cobalt (Co), a characteristic element of cosmic dust. This method requires the use of standard samples with known sedimentation rates or the cobalt (Co) content of sediment sources. Once there is no relevant data on the shale formation to be analyzed, it is still impossible to accurately calculate the sedimentation rate.

[0005] Therefore, there is an urgent need to establish a relatively efficient, fast and sufficiently accurate quantitative analysis method for the sedimentation rate of black shale in ancient lakes. Summary of the invention

[0006] The present application provides a method and device for determining the sedimentation rate of black shale in ancient lakes. The method corrects the total amount of Co element in black shale to obtain the Co element content from cosmic dust in black shale, and then accurately calculates the sedimentation rate of black shale in ancient lakes.

[0007] In a first aspect, the present application provides a method for determining the deposition rate of black shale in ancient lakes, the method comprising:

[0008] The black shale section in the drill core was sampled and the total organic carbon content, total rare earth elements and total cobalt Co in each sample were determined;

[0009] A first correction relationship is established according to the total organic carbon content and the total amount of the Co element, and the Co element content caused by biological activities is eliminated according to the first correction relationship to obtain a first Co element content;

[0010] A second correction relationship is established according to the first Co element content and the total amount of the rare earth element, and a second Co element content is obtained by eliminating the Co element content brought by the material source input according to the second correction relationship;

[0011] According to the distribution characteristics of the Co element content data of the sample, the second Co element content is processed to obtain the Co element content from cosmic dust in the shale;

[0012] The deposition rate of black shale in the ancient lake is determined based on the Co element content from cosmic dust and the Co element deposition flux of cosmic dust.

[0013] In a second aspect, an embodiment of the present invention further provides a device for determining the deposition rate of black shale in an ancient lake, the device comprising: a memory and a processor; the memory is used to store a program for determining the deposition rate of black shale in an ancient lake, the processor is used to read and execute the program for determining the deposition rate of black shale in an ancient lake, and execute any one of the methods described in the above embodiments.

[0014] In a third aspect, an embodiment of the present invention further provides a computer-readable storage medium, on which a data processing program is stored, and the data processing program is executed by a processor to perform the method for determining the deposition rate of black shale in ancient lakes as described in any of the above embodiments.

[0015] Compared with the related art, the present application provides a method and device for determining the deposition rate of black shale in ancient lakes, the method comprising: sampling the black shale section in the drilling core, and determining the total organic carbon content, the total amount of rare earth elements and the total amount of cobalt Co in each sample; establishing a first correction relationship based on the total organic carbon content and the total amount of Co, eliminating the Co element content brought by biological activities according to the first correction relationship to obtain a first Co element content; establishing a second correction relationship based on the first Co element content and the total amount of rare earth elements, eliminating the Co element content brought by material source input according to the second correction relationship to obtain a second Co element content; processing the second Co element content according to the distribution characteristics of the sample Co element content data to obtain the Co element content from cosmic dust in the shale; determining the deposition rate of black shale in ancient lakes according to the Co element content from cosmic dust and the Co element deposition flux of cosmic dust. The present application corrects the total amount of Co in black shale to obtain the Co element content from cosmic dust in black shale, and then accurately calculates the deposition rate of black shale in ancient lakes.

[0016] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0018] Figure 1 This is a flow chart of a method for determining the deposition rate of black shale in an ancient lake according to an embodiment of the present application;

[0019] Figure 2 A schematic diagram of a device for determining the deposition rate of black shale in an ancient lake according to an embodiment of the present application;

[0020] Figure 3 For some exemplary embodiments, the G135 well Co S Schematic diagram of the TOC intersection diagram and trend line fitting;

[0021] Figure 4 In some exemplary embodiments, well G135 Co′ S Schematic diagram of the intersection plot with ∑REE and trend line fitting;

[0022] Figure 5 For some exemplary embodiments, the well Co" of G135 S Schematic diagram of abnormal data analysis;

[0023] Figure 6 Schematic diagram of the lithology characteristics and shale deposition rate recovery results of the 73rd section of the G135 well in some exemplary embodiments. DETAILED DESCRIPTION

[0024] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0025] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0026] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0027] The Earth's surface is constantly receiving cosmic dust, and the deposition rate has remained stable during the geological history. Cobalt (Co) is one of the important characteristic chemical elements of cosmic dust. The abundance of Co in meteorites and cosmic dust is relatively high, and the abundance in the crust is relatively low, and there is basically no hydrochemical migration. The Co element in the crust will be enriched as it is transported from the source area to the collection area and the debris particles become finer, resulting in the Co element from the source area in the shale being significantly higher than the parent rock and coarse-grained conglomerate in the source area. The Co content of mantle-derived materials (especially basic and ultrabasic materials) in the deep Earth is high. If there is a basic magma eruption during the deposition of shale, the abundance of Co in the surrounding sedimentary rocks during the same period will be abnormal. In addition, the metabolism of algae and other organisms in lakes will lead to the enrichment of Co in organisms. Therefore, for lake environments with abundant organisms (which will cause high abundance of organic matter) or accompanied by strong volcanic activity (especially partial basic magma activity), the input of Co in shale related to biological action, source transportation and volcanic activity cannot be ignored. Based on this, the total amount of Co in shale (Co S ) can be expressed as:

[0028] Co S =Co U +Co B +Co P +Co V (1)

[0029] Among them, Co S is the total amount of Co element; Co U The Co content of cosmic dust, Co B The Co content brought to biological activities, Co P The Co content brought by the source, Co V The Co content brought by volcanic activity.

[0030] The enrichment behavior of Co in the source is very similar to that of rare earth elements, which makes Co in black shale P It has a good correlation with the total amount of rare earth elements (∑REE), Co P It can be written as f1(∑REE). Similarly, the more prosperous the microorganisms in the lake, the higher the Co B The higher the content, the higher the TOC and Co content in black shale. B There is a positive correlation, Co B It can be written as f2(TOC). Then formula (1) can be rewritten as:

[0031] Co S =Co U +f1(∑REE)+Co V +f2(TOC) (2)

[0032] The inventors found that the current methods for recovering the sedimentation rate of black shale in ancient lakes have problems such as low accuracy of shale sedimentation age anchor points, failure to consider lake sedimentation discontinuities, and difficulty in obtaining key background parameters or standard samples. The inventors proposed using Co in the source to recover the sedimentation rate of black shale in ancient lakes. P Between ∑REE and Co B Based on the characteristic of the correlation between Co and TOC, the Co element brought by biological activities and the Co element brought by the material source in the shale are eliminated. Then, according to the distribution characteristics of the Co element content data of the shale samples, the samples with abnormal Co element abundance caused by volcanic activities (and the samples with abnormal Co element abundance that may exist in the element determination process) are eliminated, and finally the Co element content Co from cosmic dust in the shale is obtained. U The black shale deposition rate of the ancient lake was calculated based on the stable Co element deposition flux of cosmic dust.

[0033] The present invention provides a method for determining the deposition rate of black shale in ancient lakes. Figure 1 As shown, the method includes steps S100-S140:

[0034] S100: Sampling the black shale section in the drill core and determining the total organic carbon content, the total amount of rare earth elements ∑REE and the total amount of cobalt Co in the samples;

[0035] S110: establishing a first correction relationship according to the total organic carbon content and the total amount of the Co element, and eliminating the Co element content caused by biological activities according to the first correction relationship to obtain a first Co element content;

[0036] S120: establishing a second correction relationship according to the first Co element content and the total amount of the rare earth element, and eliminating the Co element content brought by the source input according to the second correction relationship to obtain a second Co element content;

[0037] S130: processing the second Co element content according to the distribution characteristics of the Co element content data of the shale sample to obtain the Co element content from cosmic dust in the shale;

[0038] S140: Determine the black shale deposition rate of the ancient lake according to the Co element content from the cosmic dust and the Co element deposition flux of the cosmic dust.

[0039] In this embodiment, the black shale development section is identified based on the drilling core observation, and the black shale section is sampled; the total organic carbon content TOC (%), the total amount of rare earth elements (∑REE, 10 -6 ) and Co element content (Co S , 10 -6). Among them, the identification standard of black shale can be: the appearance of black shale is black to grayish black, with a small amount of carbonized organic matter visible, which can stain hands, and the mineral components of the rock include clay minerals, quartz, feldspar, etc., with a small amount of carbonate rock components, and more than 50% of the particles have a diameter of less than 0.0625mm.

[0040] The standards and requirements for sampling the black shale section include: within a stratigraphic unit (such as a group, section, or subsection), the sampling interval for the black shale section should be less than 1 meter, and the recommended sampling interval is 0.1-0.3m. The number of sampling points for the black shale section should be greater than 10, and the sample collected at each sampling point should be in block shape, not contaminated by any organic matter, and the sample volume should be greater than 100g; the sample number increases from the bottom of the section to the top.

[0041] The total organic carbon content (TOC) and the total amount of rare earth elements (∑REE, 10 -6 ) and Co element content (Co S , 10 -6 ) detection method, including: determining the total organic carbon content of the sample according to the method described in SY / T5116-1997; determining the total amount of rare earth elements ΣREE and the total amount of cobalt Co in the sample according to the method described in GB / T14506.30-2010. Among them, the total organic carbon content (TOC) is the total amount of organic matter in the rock expressed by the carbon content. The total amount of rare earth elements (ΣREE) is the sum of the contents of all rare earth elements in the shale sample, expressed as 10 -6 express.

[0042] In an exemplary embodiment, a first correction relationship is established based on the total organic carbon content and the total amount of the Co element, and the Co element content caused by biological activities is eliminated based on the first correction relationship to obtain a first Co element content, including:

[0043] S1101, establishing an intersection diagram of the total organic carbon content and the total amount of Co elements, and obtaining a linear trend line of the total organic carbon content and the total amount of Co elements;

[0044] S1102, using a first rotation formula to correct the total amount of the Co element, eliminating the Co element content caused by biological activities to obtain a first Co element content.

[0045] In an exemplary embodiment, a linear trend line of total organic carbon content and total amount of Co element is established in S1101 (total organic carbon content TOC is the horizontal axis, and total amount of Co element is the vertical axis). The least squares method is used to fit the linear trend line. The fitted linear trend line is:

[0046] Co S =a1·TOC+b1

[0047] Among them, Co S is the total amount of Co element, TOC is the total organic carbon content, a1 is the slope of the trend line, and b1 is the intercept of the trend line.

[0048] In an exemplary embodiment, the first rotation formula is:

[0049] Co′ S =Co S -a1·(TOC-TOC m )

[0050] Among them, Co′ S is the first Co element content, that is, the content of Co excluding B (Co content brought by biological activities) after the shale Co abundance, Co S is the total amount of Co element, a1 is the slope of the trend line, TOC is the total organic carbon content, TOC m It is the minimum value of total organic carbon (TOC) in shale samples.

[0051] The minimum value of total organic carbon (TOC) in shale samples m The samples can be sorted by TOC size to find the smallest TOC value.

[0052] In an exemplary embodiment, a second correction relationship is established according to the first Co element content and the total amount of the rare earth element, and the Co element content caused by the source input is eliminated according to the second correction relationship to obtain a second Co element content, including:

[0053] S1201, establishing an intersection diagram according to the first Co element content and the total amount of the rare earth element, and obtaining a linear trend line of the total amount of the rare earth element and the first Co element content;

[0054] S1202. Use the second rotation formula to correct the total amount of Co element in the shale, eliminate the Co element content brought by the source, and obtain a second Co element content.

[0055] In an exemplary embodiment, a linear trend line between the total amount of rare earth elements and the first Co element content is established in S1201 (the total amount of rare earth elements ∑REE is the horizontal axis, the first Co element Co′ S The least square method can be used to fit the linear trend line, and the fitted linear trend line is:

[0056] Co′ S =a2·∑REE+b2

[0057] Among them, Co′ Sis the first Co element content, ∑REE is the total amount of rare earth elements, a2 is the slope of the trend line, and b2 is the intercept of the trend line.

[0058] In an exemplary embodiment, the second rotation formula is:

[0059] Co″ S =Co′ S -a2·(∑REE-∑REE m )

[0060] Among them, Co S The second Co element content is to further remove Co P (Co element content brought by the source) shale Co element abundance, Co′ S is the first Co element content, a2 is the slope of the trend line, ∑REE is the total amount of rare earth elements, ∑REE m The minimum total amount of rare earth elements in shale samples. The minimum total amount of rare earth elements in shale samples ∑REE m The smallest ∑REE can be obtained by sorting the total rare earth element values ​​of the samples according to their size. m .

[0061] In an exemplary embodiment, the second Co element content is processed according to the distribution characteristics of the Co element content data of the shale sample to obtain the Co element content Co from cosmic dust in the shale. U ,include:

[0062] S1301, sorting the second Co element content to obtain a second Co element content sequence set;

[0063] S1302, using the quantile formula to calculate the positions of the first quartile, the second quartile, and the third quartile in the second Co element content sequence set, and obtaining the corresponding quartiles to calculate the interquartile range; the interquartile range is IQR=Q3-Q1;

[0064] Among them, the quantile formula is:

[0065]

[0066] In the above formula, Q1 is the first quartile, Q2 is the second quartile, Q3 is the third quartile, and n is the number of samples.

[0067] S1303, determine the outlier range; determine Q3+1.5×IQR and Q1-1.5×IQR as outlier cutoff points;

[0068] S1304, deleting the data points within the abnormal value range to determine the Co content of the shale from cosmic dustU ; This step is to effectively check sample abnormal values, that is, values ​​that are too large or too small are considered unreasonable, among which, values ​​that are too large are considered to be related to volcanic activity.

[0069] Taking Q3+1.5×IQR and Q1-1.5×IQR as outlier cutoff points, the outlier data points outside the range of Q1-1.5×IQR to Q3+1.5×IQR were eliminated to obtain valid shale samples that were not affected by volcanic activity. The Co″ S That is the Co element content from cosmic dust Co U .

[0070] If the total number of data outliers removed in this step exceeds 5% of the total number of samples, it is considered that the accuracy of the analysis and test results of the batch of samples is low, and the calculated results cannot guarantee accuracy.

[0071] In an exemplary embodiment, the black shale deposition rate of the ancient lake is determined according to the Co element content from the cosmic dust and the Co element deposition flux of the cosmic dust, including:

[0072] The Co″ calculated by the above steps S That is, the Co content from cosmic dust, and the sedimentation rate of black shale in ancient lakes are determined using the sedimentation rate formula;

[0073] Wherein, the deposition rate formula is:

[0074]

[0075] In the above formula, V is the deposition rate, Co U is the Co element content from cosmic dust, is the Co element deposition flux of cosmic dust, which is 6.48×10 -7 g / cm 2 a,ρ are shale density.

[0076] The density of the shale can be determined based on the density logging curve. If there is no density logging curve, the shale density is set to a constant: 2.4 g / cm 3 .

[0077] The process of determining the density value corresponding to the sampling point according to the density logging curve is as follows:

[0078] Determine the depth corresponding to the sampling point, determine the density logging curve value corresponding to the depth, and use the value as the density value of the current sampling point.

[0079] The method for determining the deposition rate of black shale in ancient lakes implemented in this embodiment does not require precise age anchor points, standard samples, or provenance analysis of the studied area. The analysis and calculation principle is simple, the process is fast, and the accuracy is high.

[0080] The embodiment of the present invention provides a device for determining the deposition rate of black shale in ancient lakes, such as Figure 2 As shown, the device includes: a memory 200 and a processor 210; the memory is used to store a program for determining the deposition rate of black shale in ancient lakes, and the processor is used to read and execute the program for determining the deposition rate of black shale in ancient lakes, and execute the method for determining the deposition rate of black shale in ancient lakes described in any one of the above embodiments.

[0081] An embodiment of the present invention further provides a computer-readable storage medium, on which a data processing program is stored. The data processing program is executed by a processor to perform the method for determining the deposition rate of black shale in ancient lakes as described in any of the above embodiments.

[0082] Example 1

[0083] Taking the three black shale development sections of the core of the Chang 73 section of the Upper Triassic in Well G135 in the Ordos Basin as an example, the process of determining the deposition rate of the ancient lake black shale is as follows:

[0084] Step 1. Coring

[0085] The 73rd section of the Upper Triassic was cored, and a core length of 46 meters was obtained.

[0086] Step 2. Identify shale development sections through core observation and take samples

[0087] Through core observation, three shale development sections were identified, namely the lower black shale section (referred to as the lower section, 1844.5m-1835.0m), the middle black shale section (referred to as the middle section, 1844.5m-1835.0m), and the upper black shale section (referred to as the upper section 1815.0m-1802.6m). The three sections of shale were sampled separately, and a total of 131 samples were obtained.

[0088] Step 3. Test the core sample

[0089] The total organic carbon content TOC (%), the total amount of Co element (10 -6 ), the total amount of rare earth elements ∑REE(10 -6 ).

[0090] Step 4. Co the sample S Make an intersection diagram of the value and TOC value, such as Figure 3 As shown, the fitted linear trend line is:

[0091] Co=0.2615TOC+14.604.

[0092] Step 5. Remove the Co element brought by biological action

[0093] Using the formula Co′ S =Co S -0.2615·(TOC-TOC m ) Eliminate the Co element (Co B ), and obtain Co′ S .TOC m It is the minimum organic carbon content among the 131 samples.

[0094] Step 6. Co′ of the sample S The value and the ∑REE value are intersected, such as Figure 4 As shown, the fitted linear trend line is:

[0095] CO′ S =0.034∑REE+9.4162.

[0096] Step 7. Eliminate the Co element (Co P )

[0097] Using the formula Co″ S =Co′ S -0.0343·(∑REE-∑REE m ) Eliminate the Co element (Co P ), and obtain the second Co element content Co″ S ,∑REE m This is the minimum total amount of rare earth elements among the 131 samples.

[0098] Step 8. The second Co element content Co" S Sorting is performed to obtain a second Co element content sequence set;

[0099] Calculate Co″ using the quantile formula S The positions of the first quartile Q1, the second quartile (median) Q2, and the third quartile Q3 in the data set are determined, and the quartiles Q1, Q2, and Q3 are determined to be 11.13, 12.69, and 14.16, respectively.

[0100] Step 9. Determine the range of outliers

[0101] The outlier cutoff points calculated based on Q3+1.5×IQR and Q1-1.5×IQR are 6.92 and 16.63. Figure 5As shown in the figure, according to the two outlier cutoff points of 6.92 and 16.63, the outliers outside the range of 6.92 to 16.63 are removed, and the Co″ of the remaining samples is S The value can be considered as the Co of the effective sample U value.

[0102] Step 10. Co U Value (i.e. Co S Substitute the value) into the deposition rate formula to obtain the deposition rate recovery result, such as Figure 6 shown.

[0103] The formula for deposition rate is:

[0104]

[0105] In the example, The fixed value is 6.48×10 -7 g / cm 2 a, shale rock density is 2.4g / cm 3 .

[0106] This example uses the cross plot analysis to effectively eliminate the Co elements brought by biological activities and the Co elements brought by material input based on the influence of organic matter, material input and volcanism on the enrichment of cobalt in black shale. And through outlier analysis, the Co content values ​​of the samples that are too large or too small are removed to eliminate the influence of volcanism and possible abnormal data points. After the above processing, the Co content from cosmic dust in the shale is obtained, and the Co content is used to calculate the sedimentation rate of the ancient lake black shale using the sedimentation velocity formula. Compared with the traditional sedimentation rate calculation method, this method does not require precise age anchor points, standard samples or material source analysis of the studied area. The analysis and calculation principle is simple, the process is fast, and the accuracy is high.

[0107] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for determining the deposition rate of black shale in ancient lakes, characterized in that: The method comprises: The black shale section in the drill core was sampled and the total organic carbon content, total rare earth elements and total cobalt Co in each sample were determined; A first correction relationship is established according to the total organic carbon content and the total amount of the Co element, and the Co element content caused by biological activities is eliminated according to the first correction relationship to obtain a first Co element content; A second correction relationship is established according to the first Co element content and the total amount of the rare earth element, and a second Co element content is obtained by eliminating the Co element content brought by the material source input according to the second correction relationship; According to the distribution characteristics of the Co element content data of the sample, the second Co element content is processed to obtain the Co element content from cosmic dust in the shale; The deposition rate of black shale in the ancient lake is determined based on the Co element content from cosmic dust and the Co element deposition flux of cosmic dust.

2. The method for determining the deposition rate of black shale in ancient lakes according to claim 1, characterized in that: The total amount of the Co element is: What S =What U +What B +What P +What V Among them, Co S is the total amount of Co element; Co U The Co content of cosmic dust, Co B The Co content brought to biological activities, Co P The Co content brought by the source input, Co V The Co content brought by volcanic activity.

3. The method for determining the deposition rate of black shale in ancient lakes according to claim 2, characterized in that: The step of establishing a first correction relationship based on the total organic carbon content and the total amount of the Co element, and eliminating the Co element content caused by biological activities according to the first correction relationship to obtain a first Co element content, comprises: Establish an intersection diagram of the total organic carbon content and the total amount of Co element to obtain a linear trend line between the total organic carbon content and the total amount of Co element; The total amount of the Co element is corrected using the first rotation formula to eliminate the Co element content caused by biological activities to obtain the first Co element content.

4. The method for determining the deposition rate of black shale in ancient lakes according to claim 3, characterized in that: The linear trend line of the total organic carbon content and the total amount of Co element is: What s =a1·TOC+b1 Among them, Co S is the total amount of Co element, TOC is the total organic carbon content, a1 is the slope of the trend line, and b1 is the intercept of the trend line.

5. The method for determining the deposition rate of black shale in ancient lakes according to claim 4, characterized in that: The first rotation formula is: What' S =What S -a1 (TOC-TOC m ) Among them, CO′ S is the first Co element content, TOC m It is the minimum value of total organic carbon (TOC) in the sample.

6. The method for determining the deposition rate of black shale in ancient lakes according to claim 2, characterized in that: The step of establishing a second correction relationship based on the first Co element content and the total amount of the rare earth element, and eliminating the Co element content brought by the source input according to the second correction relationship to obtain a second Co element content includes: Establishing an intersection diagram according to the first Co element content and the total amount of the rare earth element to obtain a linear trend line of the total amount of the rare earth element and the first Co element content; The second rotation formula is used to correct the total amount of Co in shale, eliminating the Co content brought by source input to obtain the second Co content.

7. The method for determining the deposition rate of black shale in ancient lakes according to claim 6, characterized in that: The linear trend line of the total amount of rare earth elements and the first Co element content is: <h2 style=";text-align:left;direction:ltr">Co′<h2 style=";text-align:left;direction:ltr"> s <h2 style=";text-align:left;direction:ltr"> =a2·∑REE+b2 Among them, Co′ S is the first Co element content, ∑REE is the total amount of rare earth elements, a2 is the slope of the trend line, and b2 is the intercept of the trend line.

8. The method for determining the deposition rate of black shale in ancient lakes according to claim 7, characterized in that: The second rotation formula is: Co″ S =Co′ S -a2·(∑REE-∑REE m ) Among them, Co S is the second Co element content, ∑REE m It is the minimum value of the total amount of rare earth elements in the sample.

9. The method for determining the deposition rate of black shale in ancient lakes according to claim 8, characterized in that: The Co element content from cosmic dust in the shale is obtained by processing the second Co element content according to the distribution characteristics of the Co element content data of the shale sample. U ,include: Sorting the second Co element content to obtain a second Co element content sequence set; Calculate the positions of the first quartile, the second quartile, and the third quartile in the second Co element content sequence set using the quantile formula, and obtain the corresponding quartiles to calculate the interquartile range; Determine the outlier value range of the Co element according to the quartile and the interquartile range; The Co content of shale from cosmic dust was determined by deleting the data points within the outlier range of the Co element. U ; Among them, the quantile formula is: In the above formula, Q1 is the first quartile, Q2 is the second quartile, Q3 is the third quartile, and n is the number of samples.

10. The method for determining the deposition rate of black shale in ancient lakes according to claim 1, characterized in that: Determining the black shale deposition rate of the ancient lake according to the Co element content from the cosmic dust and the Co element deposition flux of the cosmic dust includes: According to the Co element content from the cosmic dust and the Co element deposition flux of the cosmic dust, the deposition rate of the black shale in the ancient lake is determined using the deposition rate formula; Wherein, the deposition rate formula is: In the above formula, V is the deposition rate, Co U is the Co element content from cosmic dust, is the Co element deposition flux of cosmic dust, and ρ is the shale density.

11. A device for determining the sedimentation rate of black shale in ancient lakes, characterized in that: The device includes: a memory and a processor; the memory is used to store a program for determining the deposition rate of black shale in ancient lakes, and the processor is used to read and execute the program for determining the deposition rate of black shale in ancient lakes, and execute the method described in any one of claims 1-10.

12. A computer-readable storage medium having a data processing program stored thereon, wherein the data processing program is executed by a processor to implement the method for determining the deposition rate of black shale in ancient lakes as described in any one of claims 1 to 10.

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