A method and apparatus for determining the rate of deposition of lacustrine black shale

Abstract

The application relates to a method and device for determining the deposition rate of ancient lake black shale, which comprises the following steps: sampling black shale segments in a drilling core and measuring the total organic carbon content, total rare earth element content and total cobalt (Co) element content of each sample; establishing a corresponding first correction relationship according to the total organic carbon content and the total Co element content; eliminating the C o element content caused by biological activity to obtain a first Co element content according to the first correction relationship; establishing a corresponding second correction relationship according to the first Co element content and the total rare earth element content; eliminating the Co element content caused by source input to obtain a second Co element content according to the second correction relationship; processing the second Co element content according to the distribution characteristics of sample Co element content data to obtain the Co element content of cosmic dust in the shale; and determining the deposition rate of ancient lake black shale according to the Co element content of cosmic dust and the Co element deposition flux of cosmic dust.

Description

Technical Field

[0001] This article relates to the field of basic research technology in petroleum geology, and in particular to a method and apparatus for determining the deposition rate of black shale in ancient lakes. Background Technology

[0002] Lacustrine black shale serves as both a primary source rock for conventional oil and gas reservoirs and a crucial reservoir for unconventional oil and gas deposits such as shale oil and shale gas. During the sedimentation and gradual burial of organic matter from the lake surface to the bottom, it is partially decomposed by heterotrophic microorganisms, with only a small portion preserved in the shale. Faster sedimentation rates result in less time for organic matter to undergo oxidation and microbial decomposition, which is more conducive to the enrichment of organic matter in shale. Therefore, accurately reconstructing the sedimentation rate of paleolacus black shale is crucial for studying the enrichment process of organic matter in shale and evaluating the exploration and development potential of shale oil and gas.

[0003] In some techniques, obtaining high-resolution sedimentary rates for ancient lacustrine black shale relies primarily on comprehensive cyclic stratigraphic analysis. This cyclic stratigraphic analysis method first requires precise age anchor points at the top and bottom of the shale strata (to determine the depositional timeframe of the shale), and assumes that the shale was deposited continuously. However, lake water bodies are greatly affected by seasonal changes and climate variations, with lake levels often fluctuating significantly and even experiencing brief periods of drying up (depositional hiatuses); furthermore, as the geological age of the strata increases, the sedimentary rate changes... 14 When C-dating cannot be applied, U-Pb dating is not accurate enough to calculate the deposition rate of thinner strata (short deposition time).

[0004] Some techniques propose using cobalt (Co), a characteristic element of cosmic dust, to calculate lake sedimentation rates. However, this method requires the use of standard samples with known sedimentation rates or the Co / Co content of sediment sources. If relevant data is unavailable for the shale formation being analyzed, accurate calculation of sedimentation rates remains impossible.

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

[0006] This application provides a method and apparatus for determining the deposition rate of ancient lake black shale. The method corrects the total amount of Co in the black shale to obtain the Co content from cosmic dust in the black shale, thereby accurately calculating the deposition rate of ancient lake black shale.

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

[0008] Sampling black shale segments in a drilling core, and determining total organic carbon content, total rare earth element content and total cobalt Co element content in each sample;

[0009] Establishing a first correction relationship according to the total organic carbon content and the total Co element content, eliminating Co element content caused by biological activity according to the first correction relationship to obtain a first Co element content;

[0010] Establishing a second correction relationship according to the first Co element content and the total rare earth element content, eliminating Co element content caused by source input according to the second correction relationship to obtain a second Co element content;

[0011] Processing the second Co element content according to distribution characteristics of sample Co element content data to obtain Co element content from cosmic dust in shale;

[0012] Determining a paleolake black shale deposition rate according to the Co element content from cosmic dust and a Co element deposition flux of cosmic dust.

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

[0014] In a third aspect, an embodiment of the present application further provides a computer readable storage medium, and the computer readable storage medium stores a data processing program, and the data processing program is executed by a processor to execute the method for determining a paleolake black shale deposition rate in any one of the above embodiments.

[0015] Compared with the related art, the application provides a method and device for determining a deposition rate of ancient lake black shale, and the method comprises the following steps: sampling black shale segments in a drilling core, and measuring total organic carbon content, total rare earth element content and total cobalt element content in each sample; establishing a first correction relationship according to the total organic carbon content and the total cobalt element content; eliminating cobalt element content caused by biological activity according to the first correction relationship to obtain first cobalt element content; establishing a second correction relationship according to the first cobalt element content and the total rare earth element content; eliminating cobalt element content caused by source input according to the second correction relationship to obtain second cobalt element content; processing the second cobalt element content according to distribution characteristics of sample cobalt element content data to obtain cobalt element content from cosmic dust in the shale; and determining the deposition rate of ancient lake black shale according to the cobalt element content from cosmic dust and a cosmic dust cobalt element deposition flux. The application corrects total cobalt element content in the black shale to obtain cobalt element content from cosmic dust in the black shale, and then accurately calculates the deposition rate of ancient lake black shale.

[0016] Other features and advantages of the application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the application. Other advantages of the application will be realized and attained by the methods and instrumentalities described in the description and claims. BRIEF DESCRIPTION OF DRAWINGS

[0017] The accompanying drawings are included to provide a further understanding of the application, and constitute a part of the specification, illustrate embodiments of the application, and are included to provide a further understanding of the application, and together with the description, serve to explain the principles of the application.

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

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

[0020] Figure 3 Co of G135 well in some exemplary embodiments S A crossplot with TOC and a trend line fitting schematic diagram

[0021] Figure 4 Co' of G135 well in some exemplary embodiments S A crossplot with ΣREE and a trend line fitting schematic diagram

[0022] Figure 5 Co'' of G135 well in some exemplary embodiments S An abnormal data analysis schematic diagram

[0023] Figure 6 Figure 4 is a graph showing the lithology characteristics and shale deposition rate recovery results for the G135 well long 73 section for some example embodiments. DETAILED DESCRIPTION

[0024] A number of embodiments are described herein, but it should be understood that the description herein is illustrative only and is not intended to limit the scope of the application. Numerous variations and modifications will become apparent to those skilled in the art once the nature of the application is understood. Descriptions of specific alternative embodiments does not limit the scope of the application. Any feature or element in any embodiment can be used in combination with any other feature or element in any other embodiment, or in combination with any other feature or element in the same embodiment. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The use of "adapted to" does not mean "necessary" or "indispensable."

[0025] The application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed herein can also be combined with any conventional feature or element to form a unique application that is distinct from the application defined by the claims. Any feature or element of any embodiment can also be combined with features or elements from other applications to form another unique application that is defined by the claims. Therefore, it is to be understood that any feature shown and / or discussed in the present application can be implemented alone or in any suitable combination. Embodiments are, therefore, not to be limited to anything discussed in the specification unless otherwise specifically stated. Moreover, various modifications and changes can be made thereto within the scope and spirit of claims, which are to be accorded the broadest of interpretations so as to encompass all equivalent techniques and procedures.

[0026] Furthermore, in describing representative embodiments, the specification can have presented the method and / or process as a particular sequence of steps. However, to the extent that the method or process depends on more than one step, the method or process should not be limited to the particular sequence of steps described. Other sequences of steps can be possible, depending on the implementation, without departing from the spirit and scope of the present application. Thus, the particular sequence of steps set forth in the specification is not a limitation of the application. Other steps can be utilized without departing from the spirit and scope of the present application. Moreover, the claims should not be read to be limited to the combination of elements addressed in the specification unless such a limitation is expressly recited in the claims.

[0027] The Earth's surface is constantly being bombarded by cosmic dust and the deposition rate has remained stable throughout the geological history. Cobalt (Co) is one of the important cosmic dust characteristic elements, with relatively high abundance in meteorites and cosmic dust, and relatively low abundance in the crust, and with little hydrochemical migration. The Co element in the crust is enriched with the transportation from the source area to the sink area and the fining of the detrital particles, resulting in the Co element in shale from the source area being significantly higher than that in the source rock and coarse-grained sandstone. The Co content in the deep mantle source material (especially basic and ultrabasic material) is high, and if there is basic magma eruption during the deposition of shale, the Co element abundance in the surrounding sedimentary rocks of the same period will be abnormal. In addition, the metabolism of algae and other organisms in lakes will lead to the enrichment of Co elements in the organisms. Therefore, for lake environments with abundant organisms (which will cause high organic matter abundance) or with strong volcanic activity (especially basic magma activity), the input of Co elements related to biological action, source transportation and volcanic activity in shale cannot be ignored. Accordingly, the total Co element content (Co S ) in shale can be expressed as:

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

[0029] wherein Co S is the total Co element content; Co U is the Co element content brought by cosmic dust, Co B is the Co element content brought by biological activity, Co P is the Co element content brought by source, and Co V is the Co element content brought by volcanic activity.

[0030] The enrichment behavior of Co element in the source is similar to that of rare earth elements, so the Co P in black shale has a good correlation with the total rare earth element content (∑REE), and Co P can be written as f1(∑REE). Similarly, the more abundant the microorganisms in the lake, the higher the Co B content, and the TOC in black shale has a positive correlation with Co B , and Co B 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 find that the current method for restoring the deposition rate of ancient lacustrine black shale has the problems of low accuracy of shale deposition age anchor point, inability to consider lacustrine deposition discontinuity, and difficulty in obtaining key background parameters or standard samples. The inventors propose to use the Co P content in the source area to establish a correlation between the Co B content and the total rare earth element content (ΣREE) and the total organic carbon content (TOC) of the shale, eliminate the Co element caused by biological activity and the Co element caused by the source area, and then eliminate samples (and Co element abundance abnormal samples that may exist in the element determination process) caused by volcanic activity according to the distribution characteristics of the Co element content data of the shale samples, to finally obtain the Co U element content from cosmic dust in the shale Co U . The deposition rate of ancient lacustrine black shale is calculated according to the stable Co element deposition flux of cosmic dust.

[0033] The embodiment of the present application provides a method for determining the deposition rate of ancient lacustrine black shale, as shown in Figure 1 , the method comprises steps S100-S140:

[0034] S100: sampling the black shale section in the drilling core and measuring the total organic carbon content, the total rare earth element content (ΣREE) and the total Co element content in the sample;

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

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

[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: determining the deposition rate of ancient lacustrine black shale according to the Co element content from cosmic dust and the Co element deposition flux of cosmic dust.

[0039] In the embodiment, the black shale section is sampled according to the observation and identification of the black shale development section in the drilling core; the total organic carbon content (TOC, %), the total rare earth element content (ΣREE, 10 -6 ) and the Co element content (Co S , 10 -6The black shale identification standard can be that the black shale appears black or gray black, a small amount of carbonized organic matter is visible, the rock can dye hands, the mineral composition of the rock includes clay minerals, quartz, feldspar and the like, and a small amount of carbonate rock components, and more than 50% of the particle diameters are less than 0.0625 mm.

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

[0041] The detection method for measuring and calculating the total organic carbon content TOC (%) of each shale sample, the total amount of rare earth elements (ΣREE, 10 -6 ) and the total amount of Co elements (Co S , 10 -6 ) includes that: the total organic carbon content of the sample is measured according to the method described in SY / T5116-1997; the total amount of rare earth elements ΣREE and the total amount of Co elements of the sample are measured according to the method described in GB / T14506.30-2010. The total organic carbon content (TOC) is used to represent the total amount of organic matter in the rock in terms of the content of carbon. The total amount of rare earth elements (ΣREE) is the sum of the contents of all rare earth elements in the shale sample, which is represented by 10 -6 .

[0042] In an example embodiment, a first correction relationship is established according to the total organic carbon content and the total amount of Co elements, and a first Co element content is obtained by eliminating the Co element content caused by biological activity according to the first correction relationship, including:

[0043] S1101, a cross plot of the total organic carbon content and the total amount of Co elements is established to obtain a linear trend line of the total organic carbon content and the total amount of Co elements;

[0044] S1102, the total amount of Co elements is corrected by using a first rotation formula to eliminate the Co element content caused by biological activity to obtain a first Co element content.

[0045] In an example embodiment, the linear trend line of the total organic carbon content and the total amount of Co elements (the total organic carbon content TOC is the horizontal coordinate, and the total amount of Co elements is the vertical coordinate) established in S1101 adopts a least square method to fit a linear trend line, and the fitted linear trend line is:

[0046] Co S =a1·TOC+b1

[0047] wherein Co S is the total Co content, 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 example embodiment, the first rotation formula is:

[0049] Co′ S = Co S - a1 · (TOC - TOC m )

[0050] wherein Co′ S is the first Co content, i.e., the shale Co abundance after removing the Co B content due to biological activity, and Co S is the total Co content, a1 is the slope of the trend line, and TOC is the total organic carbon content. m TOC

[0051] The minimum TOC value TOC m in the shale sample can be obtained by sorting the samples according to the TOC values.

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

[0053] S1201. A cross plot is established according to the first Co content and the total rare earth element content to obtain a linear trend line of the total rare earth element content and the first Co content.

[0054] S1202. The total Co content in the shale is corrected by using a second rotation formula to eliminate the Co content due to the material source to obtain a second Co content.

[0055] In an example embodiment, the linear trend line of the total rare earth element content and the first Co content (the total rare earth element content ΣREE is the abscissa, and the first Co content Co′ S is the ordinate) in S1201 can be fitted by using the least square method, and the fitted linear trend line is:

[0056] Co′ S = a2 · ΣREE + b2

[0057] wherein Co′ SCo′ 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.

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

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

[0060] wherein Co″ S is the second Co element content, i.e., the shale Co element abundance further excluding Co P (element content) from the material source, 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, and ∑REE m is the minimum value of the total amount of rare earth elements in the shale sample. The minimum value of the total amount of rare earth elements in the shale sample ∑REE m can be obtained by sorting the total amount of rare earth elements in the sample according to the size. m

[0061] In an example 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 from cosmic dust in the shale Co U , including:

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

[0063] S1302, calculating the positions of the first quartile, the second quartile, and the third quartile in the second Co element content sequence set using a quantile formula, and obtaining the corresponding quartile calculation quartile distance; the quartile distance is IQR = Q3-Q1;

[0064] wherein 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 sample quantity.

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

[0068] S1304, deleting data points in the outlier range to determine the Co element content from cosmic dust in the shale Co​U This step is to effectively check the sample outliers, that is, values considered too large or too small are considered unreasonable, wherein the values considered too large are considered to be related to volcanic activity.

[0069] With Q3+1.5xIQR and Q1-1.5xIQR as the outlier cutoff points, the abnormal data points outside the range of Q1-1.5xIQR~Q3+1.5xIQR are removed to obtain effective shale samples not affected by volcanic activity, and the Co" of these samples S 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 test results of the batch of samples is low, and the calculated results cannot be guaranteed to be accurate.

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

[0072] The Co" calculated by the above steps S is the Co element content from cosmic dust, and the ancient lake black shale deposition rate is determined by using a deposition velocity formula;

[0073] The deposition velocity 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, and the value is 6.48x10 -7 g / cm 2 ·a, and p is the shale density.

[0076] The shale density can be determined according to the density logging curve, and if there is no density logging curve, the shale density is set to a constant: 2.4g / cm 3 .

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

[0078] Determine the depth corresponding to the sampling point, determine the density logging curve value corresponding to the depth, and take 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 anchors, 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] This invention provides an apparatus for determining the deposition rate of black shale in ancient lakes, such as... Figure 2 As shown, the apparatus includes: a memory 200 and a processor 210; the memory is used to store a program for determining the deposition rate of ancient lake black shale, and the processor is used to read and execute the program for determining the deposition rate of ancient lake black shale, and to execute the method for determining the deposition rate of ancient lake black shale as described in any of the above embodiments.

[0081] This invention also provides a computer-readable storage medium storing a data processing program, which is executed by a processor according to any one of the above embodiments, the method for determining the deposition rate of ancient lacustrine black shale.

[0082] Example 1

[0083] Taking the three black shale development sections of the Triassic Chang 73 core from well G135 in the Ordos Basin as examples, the process of determining the depositional rate of the paleolar black shale is as follows:

[0084] Step 1. Remove the core

[0085] Core samples were taken from the Upper Triassic Chang 73 section, yielding a core length of 46 meters.

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

[0087] Core observation identified three shale development sections: the lower black shale section (1844.5m–1835.0m), the middle black shale section (1844.5m–1835.0m), and the upper black shale section (1815.0m–1802.6m). Samples were taken from each of the three sections, yielding a total of 131 samples.

[0088] Step 3. Determine the core sample

[0089] The total organic carbon (TOC%) and total cobalt (Co) content of the collected samples were determined. -6 ), the total amount of rare earth elements ∑REE(10 -6 ).

[0090] Step 4. Add Co to the sample S Create a cross plot of the values ​​and TOC values, such as... Figure 3 As shown, the fitted linear trend line is:

[0091] Co = 0.2615TOC + 14.604.

[0092] Step 5. Eliminate Co element caused by biological action

[0093] Using formula Co' S = Co S - 0.2615·(TOC - TOC m ) to eliminate Co element (Co B ) caused by biological action, to obtain Co' S . TOC m is the minimum value of organic carbon content in the 131 block samples.

[0094] Step 6. Cross plot Co' S value of the sample with ∑REE value, as Figure 4 shown, the linear trend line is fitted as:

[0095] CO' S = 0.034∑REE + 9.4162.

[0096] Step 7. Eliminate Co element (Co P ) caused by source input

[0097] Using formula Co" S = Co' S - 0.0343·(∑REE - ∑REE m ) to eliminate Co element (Co P ) caused by source input, to obtain the second Co element content Co" S , ∑REE m is the minimum value of total rare earth elements in the 131 block samples

[0098] Step 8. Sort the second Co element content Co" S to obtain the second Co element content sequence set;

[0099] Using quantile formula to calculate the positions of the first quartile Q1, the second quartile (median) Q2, and the third quartile Q3 in the Co" S data set, and determine that the quartiles Q1, Q2, and Q3 are 11.13, 12.69, and 14.16, respectively.

[0100] Step 9. Determine the range of outliers

[0101] According to Q3 + 1.5 × IQR and Q1 - 1.5 × IQR, the outlier cutoff points are calculated as 6.92 and 16.63. As Figure 5As shown, based on the two outlier cutoff points of 6.92 and 16.63, 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. Add Co to the sample U Value (i.e., Co″) S Substituting the value into the deposition rate formula, the deposition rate recovery result is obtained, such as... Figure 6 As shown.

[0103] The deposition rate formula is:

[0104]

[0105] In the example, The constant is 6.48 × 10 -7 g / cm 2 •a, The density of shale rock is taken as 2.4 g / cm³. 3 .

[0106] This example demonstrates how cross-plot analysis effectively removes Co elements from biological and provenance sources in black shale, based on the influence of organic matter, provenance input, and volcanic activity on cobalt enrichment. Outlier analysis further eliminates excessively high or low Co content values, thus mitigating the influence of volcanic activity and potential anomalies. After these processing steps, the Co content from cosmic dust in the shale is obtained, and this Co content is used to calculate the depositional rate of the paleolaceous black shale using a sedimentary rate formula. Compared to traditional depositional rate calculation methods, this approach does not require precise age anchors, standard samples, or provenance analysis of the studied area. The analysis and calculation principles are simple, the process is fast, and the accuracy is high.

[0107] Those of ordinary skill in the art will realize and understand that all or some of the steps in the methods disclosed above and the functional modules / units in the systems and devices can be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementation, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component can have multiple functions, or one function or step can be performed by several physical components in cooperation. Some or all of the components can be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on computer-readable media, which can include computer storage media (or non-transitory media) and communication media (or transitory media). As is well known to those of ordinary skill in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is 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 which can be used to store the desired information and which can be accessed by a computer. Furthermore, it is common and well understood by those of ordinary skill in the art that communication media typically embodies 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 can include any information delivery media.

Claims

1. A method of determining the rate of lacustrine black shale deposition, characterized in that, The method comprises: sampling black shale segments in a drilling core, and determining total organic carbon content, total rare earth element content and total cobalt Co element content in each sample; establishing a first correction relationship according to the total organic carbon content and the total Co element content, and eliminating Co element content caused by biological activity according to the first correction relationship to obtain first Co element content; establishing a second correction relationship according to the first Co element content and the total rare earth element content, and eliminating Co element content caused by source input according to the second correction relationship to obtain second Co element content; processing the second Co element content according to distribution characteristics of sample Co element content data to obtain Co element content from cosmic dust in shale; determining a paleolake black shale deposition rate according to the Co element content from cosmic dust and a Co element deposition flux of cosmic dust; the first correction relationship according to the total organic carbon content and the total Co element content, and the first Co element content according to the first correction relationship, comprises: establishing a cross-plot of the total organic carbon content and the total Co element content to obtain a linear trend line of the total organic carbon content and the total Co element content; correcting the total Co element content by using a first rotation formula to eliminate Co element content caused by biological activity to obtain first Co element content; the second correction relationship according to the first Co element content and the total rare earth element content, and the second Co element content according to the second correction relationship, comprises: establishing a cross-plot of the first Co element content and the total rare earth element content to obtain a linear trend line of the total rare earth element content and the first Co element content; correcting the total Co element content in shale by using a second rotation formula to eliminate Co element content caused by source input to obtain second Co element content; The Co element content in the shale from the cosmic dust is obtained by processing the second Co element content according to the distribution characteristics of the sample Co element content data U , comprising: sorting the second Co element content to obtain a second Co element content sequence set; calculating positions of first quartiles, second quartiles and third quartiles in the second Co element content sequence set by using a quantile formula, and obtaining corresponding quartile calculation quartiles; determining a Co element outlier range according to the quartiles and the quartile range; deleting data points within the range of outliers of the Co element determines the Co element content from cosmic dust in the shale Co U .

2. The method of determining the rate of lacustrine black shale deposition according to claim 1, wherein, the total Co element content is: Co S = Co U + Co B + Co P + Co V where Co S is the total Co content; Co U is the Co content from cosmic dust, Co B is the Co content from biological activity, Co P is the Co content from provenance input, Co V is the Co content from volcanism.

3. The method of determining the rate of lacustrine black shale deposition according to claim 2, wherein, the linear trend line of the total organic carbon content and the total Co element content is: Co s = a1 · TOC + b1 where Co S is the total content of Co, TOC is the total organic carbon content, a1 is the slope of the trend line, and b1 is the intercept of the trend line.

4. The method of determining the rate of lacustrine black shale deposition according to claim 3, wherein, the first rotation formula is: Co' S = Co S -a1 · (TOC - TOC m ) where Co' is the first Co content, TOC is the total organic carbon content, and TOCmin is the minimum value of the total organic carbon content in the sample. S where Co' is the first Co content, TOC is the total organic carbon content, and TOCmin is the minimum value of the total organic carbon content in the sample. m ​ 5. The method of determining the rate of lacustrine black shale deposition according to claim 4, wherein, the linear trend line of the total rare earth element content and the first Co element content is: Co' s = a2•∑REE + b2 Among them, Co′ S ΣREE represents the content of the first element Co, ΣREE represents the total amount of rare earth elements, a2 represents the slope of the trend line, and b2 represents the intercept of the trend line.

6. The method of determining the rate of lacustrine black shale deposition according to claim 5, wherein, the second rotation formula is: Co" S = Co' S - a2• (ΣREE - ΣREE m ) Among them, Co″ S The second Co element content, ΣREE m This represents the minimum total amount of rare earth elements in the sample.

7. The method of determining the rate of lacustrine black shale deposition of claim 1, wherein, 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.

8. The method of determining ancient lacustrine black shale deposition rate of claim 1, wherein, the determination of the paleolake black shale deposition rate according to the Co element content from cosmic dust and a Co element deposition flux of cosmic dust, comprises: determining the paleolake black shale deposition rate by using a deposition rate formula according to the Co element content from cosmic dust and the Co element deposition flux of cosmic dust; wherein the deposition rate formula is: In the above equation, 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 p is the shale density.

9. An apparatus for determining the rate of lacustrine black shale deposition, the apparatus comprising: The device comprises a memory and a processor; the memory is used to save a program for determining the ancient lake black shale deposition rate, and the processor is used to read and execute the program for determining the ancient lake black shale deposition rate, and execute the method of any one of claims 1-8. 10.A computer readable storage medium, having stored thereon a data processing program, the data processing program being executed by a processor to perform the method of determining the ancient lake black shale deposition rate according to any one of claims 1-8.

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