Sample preparation method and heterogeneity research method of fine-grained heterogeneous sedimentary rock sample

Abstract

The invention discloses a sample preparation method of a fine-grained heterogeneous sedimentary rock sample and a heterogeneity research method. The sample preparation method comprises the following steps: determining the direction of a reference surface according to the extension direction of the bedding surface of a fine-grained heterogeneous sedimentary rock sample, cutting and leveling the top surface and the bottom surface of the sample along the direction parallel to the reference surface, and cutting the side surface of the sample along the direction perpendicular to the reference surface, so that the shape of the cross section, parallel to the reference surface, of the sample is consistent; the sample is cut into a first rock sample and a second rock sample in the direction perpendicular to the datum plane; an XRF scanning image of the cutting surface of the second rock sample is obtained, a segmentation line sequence arranged in an up-down sequence is obtained according to data differences in the scanning image, and segmentation lines are consistent with the bedding surface at the corresponding position in direction; and sequentially cutting the first rock sample according to the segmentation line sequence to obtain a plurality of rock samples. The rock sample prepared by the method is complete in variety and good in heterogeneous representativeness, and the rock sample is a homogeneous body.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum geology and rock sample preparation, and in particular to a sample preparation method for fine-grained heterogeneous sedimentary rock samples and a heterogeneity research method. Background Art

[0002] At present, there are usually two requirements for core sampling and sample preparation in the domestic geological industry: 1) The properties of the samples should be as similar as possible to meet parallel testing; 2) The properties of the samples should be as different as possible and include all types to meet comparative testing. Fine-grained sedimentary rocks are highly heterogeneous, so when preparing samples of fine-grained sedimentary rocks for the main purpose of heterogeneity research, it is necessary to make the properties of the samples as different as possible and include all types. At present, there are few conventional technical methods for rock sample selection and sample preparation, and it is difficult to meet the resolution requirements of fine-grained sedimentary rocks with particles less than 0.0625mm (more than 50%), especially in fine-grained sedimentary rocks with strong heterogeneity, the changes in sample properties are usually at the millimeter-micrometer level. In order to finely study the heterogeneity of fine-grained sedimentary rocks, it is urgent to develop more sophisticated sample preparation methods. Summary of the invention

[0003] In order to at least partially solve the above-mentioned technical problems existing in the prior art, the inventors have made the present invention, and through a specific implementation method, provide a sample preparation method and a heterogeneity research method for fine-grained heterogeneous sedimentary rock samples, the prepared rock samples are of full types, have good heterogeneity representativeness, and the rock samples are homogeneous.

[0004] In a first aspect, an embodiment of the present invention provides a method for preparing a fine-grained heterogeneous sedimentary rock sample, comprising:

[0005] Determine the direction of the reference plane according to the extension direction of the bedding plane of the fine-grained heterogeneous sedimentary rock sample, cut the top and bottom surfaces of the sample in a direction parallel to the reference plane and make them flat, and cut the side surfaces of the sample in a direction perpendicular to the reference plane so that the shapes of the cross sections of the sample parallel to the reference plane are consistent;

[0006] Cutting the sample into a first rock sample and a second rock sample along a direction perpendicular to a reference plane;

[0007] Obtaining an XRF scan of the cut surface of the second rock sample, and obtaining a sequence of segmentation lines arranged in a vertical order according to data differences in the scan, wherein the segmentation lines are consistent in direction with the bedding planes at corresponding positions;

[0008] The first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples.

[0009] In some embodiments, determining the reference plane direction according to the extension direction of the bedding plane of the fine-grained heterogeneous sedimentary rock sample includes:

[0010] Count the bedding plane directions of fine-grained heterogeneous sedimentary rock samples and determine the direction with the most bedding planes as the reference plane direction; or,

[0011] Based on the directions of bedding planes of fine-grained heterogeneous sedimentary rock samples, the base plane direction is obtained by cluster analysis.

[0012] In some embodiments, the volume ratio of the first rock sample to the second rock sample is greater than 10;

[0013] The cutting surface width of the second rock sample is 1 to 5 cm.

[0014] In some embodiments, the XRF scans are multiple distribution diagrams of the content of set elements, and the sequence of segmentation lines arranged in a top-to-bottom order is obtained according to the data differences in the scans, including:

[0015] For each XRF scan image, points whose content change rate of the corresponding element is higher than a set threshold are identified to obtain a scattered point set, and multiple possible segmentation lines are obtained from the scattered point set by a scattered point clustering analysis method, wherein two endpoints of each possible segmentation line are respectively on two opposite sides of the cut surface of the second rock sample;

[0016] By using the line clustering analysis method, possible segmentation lines obtained from each XRF scanning image are clustered and analyzed to obtain a segmentation line sequence arranged in an upper and lower order.

[0017] In some embodiments, it also includes:

[0018] Determine whether the distance between two adjacent segmentation lines is less than the set distance threshold;

[0019] If so, delete one of the segmentation lines, or merge two adjacent segmentation lines whose distance is less than the set distance threshold according to the merging rule of the cluster analysis similarity principle to obtain a new segmentation line.

[0020] In some embodiments, the set distance threshold satisfies the following requirements:

[0021] The volume of the rock sample having the set distance threshold as thickness and the cross section of the first rock sample as cross section is not less than the set volume threshold.

[0022] In some embodiments, the set distance threshold is 0.2 mm.

[0023] In some embodiments, the first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples, including:

[0024] Determine at least one cutting direction perpendicular to the reference plane according to research needs, and complete vertical cutting of the first rock sample according to each cutting direction;

[0025] The first rock sample after cutting is wrapped with a set material, and the wrapped first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples.

[0026] In some embodiments, after obtaining a plurality of rock samples, the method further comprises:

[0027] The cut rock sample is cut again according to the principle of maximum volume so that the top and bottom surfaces of the rock sample are parallel.

[0028] In a second aspect, an embodiment of the present invention provides a method for studying the heterogeneity of a fine-grained heterogeneous sedimentary rock sample, comprising:

[0029] Cutting and sampling the fine-grained heterogeneous sedimentary rock sample according to the above method to obtain a plurality of rock samples;

[0030] Heterogeneity studies were carried out based on the multiple rock samples obtained.

[0031] The beneficial effects of the above technical solution provided by the embodiment of the present invention include at least:

[0032] (1) The method for preparing a fine-grained heterogeneous sedimentary rock sample provided in an embodiment of the present invention is to cut the sample into a first rock sample and a second rock sample in a direction perpendicular to the reference plane; obtain an XRF scan of the cut surface of the second rock sample, and obtain a sequence of segmentation lines arranged in an upper and lower order according to the data difference in the scan; and sequentially cut the first rock sample according to the segmentation line sequence to obtain multiple rock samples. The continuous slice preparation for the microscopic heterogeneity of fine-grained sedimentary rocks improves work efficiency and reduces sample loss rate; the segmentation lines are consistent with the bedding plane direction at the corresponding position, the prepared rock samples are of all types, the heterogeneity representativeness is good, and the rock samples are homogeneous, which provides a basis for realizing fast and high-resolution sample property judgment.

[0033] (2) The sample preparation method of fine-grained heterogeneous sedimentary rock sample provided in an embodiment of the present invention cuts the sample into a first rock sample and a second rock sample along a direction perpendicular to a reference plane; the second rock sample is not cut but is used as a reference rock sample. Since the second rock sample has the same vertical section as the first rock sample, during the cutting process of the first rock sample, the second rock sample can provide a physical reference for the analysis of the longitudinal heterogeneity distribution characteristics of the first rock sample at any time.

[0034] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings.

[0035] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 This is a flow chart of a method for preparing a fine-grained heterogeneous sedimentary rock sample in Example 1 of the present invention;

[0038] Figure 2 This is an example diagram of the sample preparation process of a fine-grained heterogeneous sedimentary rock sample in the second embodiment of the present invention;

[0039] Figure 3 This is an example diagram of a sample cross section in Example 2 of the present invention;

[0040] Figure 4 This is an example diagram of an XRF scanning image in the second embodiment of the present invention. DETAILED DESCRIPTION

[0041] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0042] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0043] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0044] In the description of the present invention, it should be noted that the terms "include", "including", "have", "contain" and the like are open terms, meaning including but not limited to.

[0045] The embodiment of the present invention aims to solve the problem of making representative samples in the process of sample experimental analysis for fine-grained sedimentary rocks with strong microscopic heterogeneity. The embodiment of the present invention provides a sample preparation method for fine-grained heterogeneous sedimentary rock samples and a heterogeneity research method. The rock samples prepared by the method are of full types, have good heterogeneity representativeness, and are homogeneous.

[0046] Embodiment 1

[0047] Embodiment 1 of the present invention provides a method for preparing a fine-grained heterogeneous sedimentary rock sample, referring to Figure 1 As shown, the following steps are included:

[0048] Step S11: Determine the direction of the reference plane according to the extension direction of the bedding plane of the fine-grained heterogeneous sedimentary rock sample, cut the top and bottom surfaces of the sample parallel to the reference plane to make them flat, and cut the side surfaces of the sample perpendicular to the reference plane to make the shape of the cross section of the sample parallel to the reference plane consistent.

[0049] The rock sample is usually a coring section, and its top surface and bottom surface are two end surfaces perpendicular to the axial direction of the coring section.

[0050] Typically, the direction of heterogeneity research is perpendicular to the dominant bedding plane. In this case, the reference plane direction can be determined in one of the following two ways:

[0051] (1) Count the bedding plane directions of fine-grained heterogeneous sedimentary rock samples and determine the direction with the most developed bedding planes as the reference plane direction.

[0052] (2) Based on the orientation of each bedding plane of fine-grained heterogeneous sedimentary rock samples, the reference plane orientation is obtained by cluster analysis.

[0053] For example, the reference plane direction finally determined is the direction with the smallest sum of differences with each reference plane, and the difference with each reference plane is determined respectively, and the direction with the smallest sum of differences is determined as the reference plane direction.

[0054] Optionally, the research direction of the heterogeneity may not be perpendicular to the dominant bedding plane direction. In this case, the direction perpendicular to the research direction of the heterogeneity is directly used as the reference plane direction.

[0055] Taking the direction of the reference plane as P and the direction perpendicular to the reference plane as V as an example, the side of the sample is cut along the direction perpendicular to the reference plane so that the shape of the cross section of the sample parallel to the reference plane is consistent. This can be done by using the sample minimum cross-sectional area polygon parallel to P or any shape smaller than the minimum cross-sectional area polygon as the boundary, set as Z, and cutting the sample polygon Z along vector V so that the cross-sectional area of ​​the sample along the direction of vector P is equal.

[0056] Step S12: cutting the sample into a first rock sample and a second rock sample along a direction perpendicular to the reference plane.

[0057] Grind the cut section to make it level with a height difference of no more than 1mm.

[0058] The first rock sample is used as a scanning and reference rock sample, and the second rock sample is used as a cut rock sample, so the volume of the first rock sample does not need to be too large. Preferably, the volume ratio of the first rock sample to the second rock sample is greater than 10.

[0059] Step S13: Obtain an XRF scan of the cut surface of the second rock sample, and obtain a segmentation line sequence arranged in an upper and lower order according to data differences in the scan.

[0060] The second rock sample is placed in the Micro-XRF (micro-area X-ray fluorescence spectrometer) instrument, and the profile is adjusted to a horizontal state; the profile is scanned using Micro-XRF to generate an XRF scan image (data), which is a content distribution map of multiple set elements.

[0061] The conditions for performing XRF scanning along vector V may be: a resolution of 5 microns, a scanning width W = 1 to 2 cm (correspondingly, the width of the cutting surface of the second rock sample is required to be 1 to 5 cm), and a scanning length H, where H is the length of the sample within the range required for heterogeneity research, preferably 1 cm to 30 cm, and the maximum does not exceed HMax or the upper limit of the sample bin of the XRF scanner. HMax is the maximum height of the rock sample, which is the vertical distance between the top and bottom surfaces of the sample.

[0062] In some embodiments, obtaining the segmentation line sequence may include:

[0063] For each XRF scan image, the points whose content change rate of the corresponding element is higher than the set threshold are identified to obtain a scatter point set. Through the scatter point clustering analysis method, multiple possible segmentation lines are obtained from the scatter point set, and the two endpoints of each possible segmentation line are respectively on the two opposite sides of the cutting surface of the second rock sample; through the line clustering analysis method, the possible segmentation lines obtained according to each XRF scan image are clustered and analyzed to obtain a segmentation line sequence arranged in upper and lower order.

[0064] The dividing line determined by the above method is a line formed by points whose corresponding element content change rates of the horizontally matched positions are higher than the set threshold value, so the dividing line is consistent with the direction of the bedding plane at the corresponding position; specifically, each dividing line is located on a bedding plane and is the line where the bedding plane intersects the cutting plane.

[0065] Fine-grained sedimentary rock refers to a sedimentary rock whose particle size meets the particle size requirements of fine-grained sedimentary rock in the classification of sedimentary rocks by particle size, that is, fine-grained sedimentary rock refers to sedimentary rock whose particle size is less than the set particle size threshold.

[0066] The fine-grained heterogeneous sedimentary rock studied in the embodiments of the present application can be specifically defined by referring to the definition in geological sedimentology. Usually, sedimentary rocks with particles smaller than 0.0625 mm (more than 50%) are defined as fine-grained sedimentary rocks.

[0067] Based on the accuracy requirements of heterogeneity research of fine-grained sedimentary rocks, it is usually necessary to prepare rock samples with a thickness of not less than 0.2 mm.

[0068] Therefore, after obtaining the segmentation line sequence through the image method, it can also include judging whether the distance between two adjacent segmentation lines is less than the set distance threshold; if so, deleting one of the segmentation lines, or merging two adjacent segmentation lines whose distance is less than the set distance threshold according to the merging rule of the similar principle of cluster analysis to obtain a new segmentation line.

[0069] The above-mentioned set distance threshold is also usually set to 0.2 mm.

[0070] For example, for TOC monitoring, the rock sample needs to be ground into powder, so the rock sample needs to meet certain volume requirements to ensure that the volume meets the research needs. Therefore, in some embodiments, the distance threshold is set to meet the following requirements:

[0071] The volume of the rock sample with the set distance threshold as the thickness and the cross section of the first rock sample as the cross section is not less than the set volume threshold.

[0072] Step S14: cutting the first rock sample in sequence according to the segmentation line sequence to obtain a plurality of rock samples.

[0073] The first rock sample can be cut according to the cutting line sequence by using a diamond wire cutting instrument.

[0074] Furthermore, since the dividing line is consistent with the direction of the bedding plane at the corresponding position, but not necessarily parallel to the reference plane, and the dividing lines are not necessarily parallel to each other, after completing the cutting of the first rock sample according to the dividing line sequence, the cut rock sample can be cut again according to the principle of maximum volume so that the top and bottom surfaces of the rock sample are parallel.

[0075] In the same vertical direction, multiple rock samples can be cut according to research needs. Therefore, in some embodiments, it can include: determining at least one cutting direction perpendicular to the reference plane according to research needs, and completing vertical cutting of the first rock sample according to each cutting direction; wrapping the cut first rock sample with a set material (industrial wax can be used for wrapping), and cutting the wrapped first rock sample in sequence according to the dividing line sequence to obtain multiple rock samples.

[0076] Furthermore, the cut rock sample can be further cut according to the principle of maximum volume so that the top and bottom surfaces of the rock sample are parallel.

[0077] The method for preparing a fine-grained heterogeneous sedimentary rock sample provided in the first embodiment of the present invention includes cutting the sample into a first rock sample and a second rock sample in a direction perpendicular to a reference plane; obtaining an XRF scan of the cut surface of the second rock sample, and obtaining a sequence of segmentation lines arranged in an upper and lower order according to the data difference in the scan; and sequentially cutting the first rock sample according to the segmentation line sequence to obtain a plurality of rock samples. The continuous slice preparation for the microscopic heterogeneity of fine-grained sedimentary rocks improves work efficiency and reduces sample loss rate; the segmentation lines are consistent with the bedding plane direction at the corresponding position, the prepared rock samples are of all types, the heterogeneity representativeness is good, and the rock samples are homogeneous, which provides a basis for realizing fast and high-resolution judgment of sample properties.

[0078] The sample preparation method of fine-grained heterogeneous sedimentary rock sample provided in Example 1 of the present invention cuts the sample into a first rock sample and a second rock sample along a direction perpendicular to a reference plane; the second rock sample will not be cut but serves as a reference rock sample. Since the second rock sample has the same vertical section as the first rock sample, during the cutting process of the first rock sample, the second rock sample can provide a physical reference for the analysis of the longitudinal heterogeneity distribution characteristics of the first rock sample at any time.

[0079] Embodiment 2

[0080] Embodiment 2 of the present invention provides a specific implementation process of a method for preparing a fine-grained heterogeneous sedimentary rock sample, referring to Figure 2 The figure is a diagram of the implementation process, which may include the following steps:

[0081] (1) The dominant bedding plane that accounts for more than 75% of the sample’s sedimentary structural bedding plane is taken as the reference plane, which is set as P.

[0082] (2) Parallel to the reference plane P, cut and level both ends of the sample, and set the perpendicular vector from the top to the bottom surface as V.

[0083] (3) Taking the limit of the sample's minimum cross-sectional area polygon parallel to the reference plane P as the boundary, set it as Z, and cut the sample polygon Z along the vector V so that the cross-sectional area of ​​the sample along the direction of the vector P is equal.

[0084] (4) The sample is cut into two parts along vector V, which are denoted as A and A'. The volume ratio of A to A' is greater than 10. The section cut in A' is polished to make it horizontal with a height difference of no more than 1 mm.

[0085] Preferably, the cross-sectional width of A' is between 1 cm and 5 cm. If it is too wide, the XRF scanning speed will be slow, and if it is too narrow, the amount of information will be small.

[0086] (5) Place sample A' into a Micro-XRF (micro-area X-ray fluorescence spectrometer) instrument and adjust the cross section to a horizontal state; use Micro-XRF to scan the cross section to generate images and data.

[0087] Preferably, the conditions for performing XRF scanning along the vector V on the cross section of the sample A' are: a resolution of 5 microns, a scanning width W=2 cm, and a scanning length H of 20 cm.

[0088] See also Figure 3 The following is an example of a cross-section of a sample; see Figure 4 As shown, an example of the obtained XRF scanning image is shown, and from left to right, they are the content distribution diagrams of Al, Fe, K, S and Si elements respectively.

[0089] Figure 4 The marks 1-10 in are the 10 determined dividing line positions. Figure 4 It can be seen from the content variation diagram of each element that the bedding plane development direction of the rock sample is basically parallel to the reference plane, so Example 2 is demonstrated by taking the example that the determined dividing lines are parallel to the reference plane direction.

[0090] (6) The dividing line is where the image difference is large or the data changes significantly, and the samples are recorded as D1, D2, .... Dn, completing the first-level sampling.

[0091] (7) Calculate the distance between adjacent segmentation lines in the first-level sampling, and merge those with a distance less than 0.2 mm. The merging rule is based on the cluster analysis principle of similarity to complete the second-level sampling. The samples are marked as S1, S2, S3, …, Sn.

[0092] (8) Sample A is cut and separated according to the secondary sampling marking result, and sample A is cut parallel to the reference plane P using a diamond wire cutter.

[0093] Preferably, before cutting sample A, sample A is first cut into several parts (the number and position are determined according to research needs) along vector V, and then wrapped with industrial wax before cutting, so that each small slice is in the corresponding position.

[0094] Preferably, before cutting sample A, the volume of the prepared sample needs to be estimated based on the area and thickness of the secondary sample in order to meet the sample quantity requirements of subsequent tests. If a test project requires a large amount of samples, it needs to be merged again to ensure the sample quantity.

[0095] It should be understood that the specific order or hierarchy of steps in the disclosed process is an example of an exemplary method. Based on design preferences, it should be understood that the specific order or hierarchy of steps in the process can be rearranged without departing from the scope of protection of the present disclosure. The attached method claims present the elements of the various steps in an exemplary order and are not intended to be limited to the specific order or hierarchy described.

[0096] In the above detailed description, various features are grouped together in a single embodiment to simplify the disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than are clearly stated in each claim. On the contrary, as reflected in the appended claims, the invention is in a state of having less than all the features of the disclosed individual embodiments. Therefore, the appended claims are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate preferred embodiment of the invention.

[0097] The above description includes examples of one or more embodiments. Of course, it is impossible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but it should be recognized by those skilled in the art that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications and variations that fall within the scope of protection of the appended claims. In addition, with respect to the term "comprising" used in the specification or claims, the word is covered in a manner similar to the term "including", just as "including," explained as a transitional word in the claims. In addition, any term "or" used in the specification of the claims is intended to represent "non-exclusive or". The terms "first" and "second" are used for descriptive purposes and are not to be understood as indicating or implying relative importance.

Claims

1. A method for preparing a fine-grained heterogeneous sedimentary rock sample, characterized in that: include: Determine the direction of the reference plane according to the extension direction of the bedding plane of the fine-grained heterogeneous sedimentary rock sample, cut the top and bottom surfaces of the sample in a direction parallel to the reference plane and make them flat, and cut the side surfaces of the sample in a direction perpendicular to the reference plane so that the shapes of the cross sections of the sample parallel to the reference plane are consistent; Cutting the sample into a first rock sample and a second rock sample along a direction perpendicular to a reference plane; Obtaining an XRF scan of the cut surface of the second rock sample, and obtaining a sequence of segmentation lines arranged in a vertical order according to data differences in the scan, wherein the segmentation lines are consistent in direction with the bedding planes at corresponding positions; The first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples.

2. The method according to claim 1, characterized in that Determining the reference plane direction according to the extension direction of the bedding plane of the fine-grained heterogeneous sedimentary rock sample comprises: Count the bedding plane directions of fine-grained heterogeneous sedimentary rock samples and determine the direction with the most bedding planes as the reference plane direction; or, Based on the bedding plane orientation of fine-grained heterogeneous sedimentary rock samples, the base plane orientation was obtained by cluster analysis.

3. The method according to claim 1, characterized in that The volume ratio of the first rock sample to the second rock sample is greater than 10; The cutting surface width of the second rock sample is 1 to 5 cm.

4. The method according to claim 1, characterized in that The XRF scans are multiple distribution diagrams of the content of set elements. The segmentation line sequence arranged in a vertical order is obtained according to the data differences in the scans, including: For each XRF scan image, points whose content change rate of the corresponding element is higher than a set threshold are identified to obtain a scattered point set, and multiple possible segmentation lines are obtained from the scattered point set by a scattered point clustering analysis method, wherein two endpoints of each possible segmentation line are respectively on two opposite sides of the cut surface of the second rock sample; By using the line clustering analysis method, possible segmentation lines obtained from each XRF scanning image are clustered and analyzed to obtain a segmentation line sequence arranged in an upper and lower order.

5. The method according to claim 4, characterized in that Also includes: Determine whether the distance between two adjacent segmentation lines is less than the set distance threshold; If so, delete one of the segmentation lines, or merge two adjacent segmentation lines whose distance is less than the set distance threshold according to the merging rule of the cluster analysis similarity principle to obtain a new segmentation line.

6. The method according to claim 5, characterized in that The set distance threshold meets the following requirements: The volume of the rock sample having the set distance threshold as thickness and the cross section of the first rock sample as cross section is not less than the set volume threshold.

7. The method according to claim 5, characterized in that The set distance threshold is 0.2 mm.

8. The method according to claim 1, characterized in that The first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples, including: Determine at least one cutting direction perpendicular to the reference plane according to research needs, and complete vertical cutting of the first rock sample according to each cutting direction; The first rock sample after cutting is wrapped with a set material, and the wrapped first rock sample is cut in sequence according to the segmentation line sequence to obtain a plurality of rock samples.

9. The method according to any one of claims 1 to 8, characterized in that: After obtaining a plurality of rock samples, the method further comprises: The cut rock sample is cut again according to the principle of maximum volume so that the top and bottom surfaces of the rock sample are parallel.

10. A method for studying the heterogeneity of fine-grained heterogeneous sedimentary rock samples, characterized in that: include: Cutting and sampling the fine-grained heterogeneous sedimentary rock sample according to any one of the methods of claims 1 to 9 to obtain a plurality of rock samples; Heterogeneity studies were carried out based on the multiple rock samples obtained.

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