Coal bed methane core depth homing method, system and device

Abstract

The application discloses a coal bed gas core depth homing method, system and equipment, which comprises the following steps: obtaining relevant data of a core based on core analysis and testing; based on the principle of consistent lithology of a marker bed, the depth of the core is overall adjusted according to the lithology parameters in the relevant data; the sampling point of the core is moved within the corresponding core segment depth range until the correlation coefficient of the ash content and the natural gamma of the sampling point is the largest, and the target homing is determined; and the depth of the core is corrected based on the target homing. The accurate sampling point in the coal core analysis and testing is found, and the real horizon and depth where the core is located are recovered.

Description

Technical Field

[0001] This invention relates to the field of coalbed methane geological analysis technology, and in particular to a method, system and equipment for repositioning coalbed methane core depths. Background Technology

[0002] For conventional core analysis and depth relocation, it is sufficient to simply shift the core analysis data of the marker layer along with the well logging depth difference. Existing technologies employ two methods: one establishes a relationship between the core analysis's physical properties and the well logging data, with the position showing the highest correlation coefficient indicating the target relocation depth; the other compares the core's natural gamma ray test data with the well logging gamma ray curve, shifting the data overall to find the target relocation depth.

[0003] Compared to sandstone and other rock formations, coal seam reservoirs are brittle, and coring is typically done using wireline methods. The core diameter is relatively small, and even slight errors in drilling pressure can cause wellbore collapse. Furthermore, the cores are often quite fragmented after exiting the core casing, making it difficult for researchers to accurately determine the depth of the plunger sample during analysis. Therefore, coal core analysis reports generally assign the analytical values ​​of a specific point to a particular sample segment, rather than a conventional depth. This results in uncertainty regarding the location of the sampling point within the sample segment. Consequently, conventional methods cannot be used to determine the depth of coalbed methane core samples. Summary of the Invention

[0004] This invention provides a method, system, equipment, and medium for locating the depth of coalbed methane core samples, which at least partially solves the technical problem of uncertain sampling point locations in the sample segment during coal core analysis and testing in the prior art. By adjusting the sampling points separately after the overall lithology is shifted, accurate sampling points can be found in coal core analysis and testing.

[0005] Firstly, to solve the above-mentioned technical problems, embodiments of the present invention provide the following technical solutions:

[0006] A method for determining the depth of coalbed methane core samples includes:

[0007] Based on core analysis and testing, relevant data from the core were obtained.

[0008] Based on the principle of consistent marker lithology, the depth of the core samples was adjusted as a whole according to the lithological parameters in the relevant data.

[0009] The sampling points of the above core samples are moved within the depth range of the corresponding core segment until the correlation coefficient between the ash content and natural gamma of the above sampling points is the largest, and the target location is determined.

[0010] The depth of the core sample was corrected based on the aforementioned target positioning.

[0011] Optionally, the steps for adjusting the overall depth of the aforementioned core sample specifically include:

[0012] Based on the location of the coal body structure or the characteristics of the natural gamma curve of the aforementioned core, the lithology of the aforementioned core is translated until the coal seam of the aforementioned lithology corresponds to the depth of the coal body structure or the depth of the coal body characteristics of the natural gamma curve.

[0013] Optionally, the steps described above for determining the target location specifically include:

[0014] When the number of the aforementioned core segments is within the first preset range;

[0015] By moving the sampling points within each core segment, the location with the highest correlation coefficient between the ash content and natural gamma of the aforementioned sampling points is found, and this location is used as the target location.

[0016] Optionally, when the number of core segments is within a second preset range, the method further includes:

[0017] All core segments are divided into multiple regions. In each of these regions, one core segment is randomly selected. By moving the sampling points within the core segment, the location with the highest correlation coefficient between ash content and natural gamma is found, and this location is used as the target location.

[0018] Optionally, the number of sampling points mentioned above is greater than 3.

[0019] Secondly, a coalbed methane core depth relocation system is provided, comprising:

[0020] The data acquisition module is used to acquire core-related data;

[0021] The coarse adjustment module, based on the principle of consistent lithology of the marker layer, makes an overall adjustment to the depth of the above core samples;

[0022] The fine-tuning module moves the sampling points of the above core samples within the corresponding core segment depth range until the correlation coefficient between the ash content and natural gamma of the above sampling points is the largest, and then determines the target location.

[0023] The repositioning module corrects the core depth based on the aforementioned target repositioning.

[0024] Optionally, the data acquisition module described above is also used to generate a corresponding first columnar section based on the core-related data described above;

[0025] The aforementioned coarse adjustment module is also used to generate a corresponding second bar chart after the overall adjustment.

[0026] The aforementioned repositioning module is also used to generate a repositioned third columnar section after correcting the core depth;

[0027] The system also includes a sorting module, which arranges the first bar chart, the second bar chart, and the third bar chart in sequence and outputs them as a process display chart.

[0028] Optionally, the above system may also include:

[0029] The fitting module is used to fit the corresponding gray values ​​and natural gamma values ​​on the first bar chart, the second bar chart, and the third bar chart, respectively.

[0030] The output module is used to output the correlation coefficient values ​​obtained from the above fitting to the corresponding histograms.

[0031] Optionally, the above system may also include:

[0032] The module is used to establish wellbore curves and natural gamma curves corresponding to lithology on the first, second, and third bar charts mentioned above, respectively, as a reference for verifying lithology.

[0033] Thirdly, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to perform the steps corresponding to the method described in the first aspect.

[0034] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0035] In this embodiment of the invention, the principle of consistent lithology of the marker layer is first used, that is, the overall lithological depth is coarsely adjusted by comparing the coal body structure and the position of characteristic points of the natural gamma curve; then, based on the positive correlation between ash content and natural gamma, the depth of individual sampling points is finely adjusted, and the position with the largest correlation coefficient between ash content and natural gamma is selected as the target location. In this way, the accurate sampling point in the coal core analysis is found, thereby restoring the true stratum and depth of the core. Attached Figure Description

[0036] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 A flowchart of a method for determining the depth of coalbed methane cores provided by this invention;

[0038] Figure 2 This is the first bar chart in this invention;

[0039] Figure 3 This is the second bar chart in this invention;

[0040] Figure 4 This is the third bar chart in this invention;

[0041] Figure 5 These are illustrations from the present invention;

[0042] Figure 6 This is a schematic diagram of a coalbed methane core depth relocation system provided by the present invention. Detailed Implementation

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0047] It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of this application, rather than limitations on the technical solutions of this application. Unless otherwise specified, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0048] The technical solution of this invention is to solve the above-mentioned technical problems, and the overall idea is as follows:

[0049] First, by comparing the coal body structure and the location of characteristic points on the natural gamma curve, the overall lithological depth is shifted. Then, based on the positive correlation between ash content and natural gamma, the depth of individual sample points is fine-tuned, and the location with the largest correlation coefficient between ash content and natural gamma is selected as the target location. In this way, accurate sampling points are found in the coal core analysis, thereby reconstructing the true stratigraphic position and depth of the core.

[0050] Example 1:

[0051] In this embodiment of the invention, the following are provided: Figure 1 The method shown includes steps S101 to S104 for determining the depth of coalbed methane core samples.

[0052] Step S101: Obtain relevant core data based on core analysis and testing;

[0053] It should be noted that core analysis and testing mainly include microscopy and spectrophotometry to obtain relevant data from the core. This data specifically includes core ash content, lithology, coal body structure, borehole diameter curves, and natural gamma curves.

[0054] Step S102: Based on the principle of consistent lithology of the marker layer, the depth of the core is adjusted as a whole according to the lithological parameters in the relevant data.

[0055] It should be noted that the principle of consistent marker lithology means that during core repositioning, cores taken from the same stratum are returned to their original positions to ensure the accuracy and reliability of core analysis results. However, after initial sampling, geological factors, drilling techniques, and sampling factors can lead to deviations or omissions in the sampled cores. Therefore, a coarse adjustment is first performed: based on the coal seam structure location or natural gamma curve characteristics of the core, the lithology of the core is shifted until the lithology of the coal seam corresponds to the depth of the coal seam structure or the depth of the coal seam characteristics in the natural gamma curve.

[0056] Among them, the coal body structure is fragmented coal, which can reflect the location of the coal seam in the lithology, such as... Figure 2 As shown, this allows for translation based on the location of the broken coal. Figure 2 The lithology of the coal seam in the middle core corresponds to the fractured coal, yielding... Figure 3 .in addition, Figure 2 The black area represents coal, the brick area represents limestone, and the rest represents mudstone. Different minerals exhibit varying natural gamma radiation intensities; by comparing these intensity characteristics, the approximate location of the coal seam can be determined, allowing for coarse-scale determination.

[0057] Step S103: Move the sampling point of the core within the corresponding core segment depth range until the correlation coefficient between the ash content and natural gamma of the sampling point is the largest, and determine the target location.

[0058] In this embodiment, the coarse adjustment is only based on the results of a rough analysis, and deviations still exist after the adjustment, such as... Figure 3 As shown, fine-tuning is therefore necessary to further improve accuracy. This is achieved by using ash content data obtained from core analysis and testing for relocation. Based on the principle of a positive correlation between ash content and natural gamma, the sampling point positions are changed within the corresponding core segment's height range until the position with the highest correlation coefficient between ash content and natural gamma is found. Figure 4 .

[0059] In detail, when the number of core segments is within a first preset range (e.g., less than 20), the location with the highest correlation coefficient between ash content and natural gamma is found by moving the sampling points within each core segment. Based on the deviation between the location and the core sample, all core segments are corrected. In other words, because the number of core segments to be processed is relatively small, the sampling points of each core segment can be located by changing their positions to ensure the accuracy of fine-tuning. The number of ash content test points needs to be greater than 3 to avoid problems with low depth positioning accuracy.

[0060] When the number of core samples is within a second preset range, for example, more than 20, all core samples are divided into multiple regions. Within each region, one core sample is randomly selected. By moving the sampling points within that core sample, the location with the highest correlation coefficient between ash content and natural gamma is found. Based on the deviation between the location and the core sample, all core samples within that region are corrected. In other words, when there are too many selected test points, searching for each one individually is computationally intensive. Instead, based on different altitude ranges, significantly different geological features can be divided into different regions. Within each region, the deviation of one core sample is calculated, and then all core samples within that region are adjusted according to this deviation, thereby reducing the computational burden.

[0061] It should be noted that the method for changing the location of sampling points can be randomized. Multiple sampling points can be randomly selected, and the correlation coefficient between ash content and natural gamma can be calculated. The location with the highest correlation coefficient is then selected as the target location. The more sampling points there are, the more accurate the target location will be. Of course, other methods for setting sampling points can also be used; there are no restrictions here.

[0062] Step S104: Correct the core depth based on the target repositioning.

[0063] Taking the application of this invention to a coalbed methane exploration well on the eastern edge of the Ordos Basin as an example, the actual effect and correction results of the depth repositioning of the coal core analysis are shown in Table 1 below.

[0064]

[0065]

[0066] Table 1

[0067] In embodiments of the present invention, the lithological depth is coarsely adjusted overall by utilizing the principle of consistent marker lithology and comparing the location of characteristic points on the coal body structure and natural gamma curve. Then, based on the positive correlation between ash content and natural gamma, the depth of individual sampling points is finely adjusted, selecting the location with the highest correlation coefficient between ash content and natural gamma as the target location. This process finds accurate sampling points for coal core analysis, thereby reconstructing the true stratigraphic position and depth of the core.

[0068] Example 2:

[0069] Based on the same inventive concept, embodiments of the present invention provide a coalbed methane core depth relocation system, such as... Figure 6 As shown, it includes:

[0070] The data acquisition module 201 is used to acquire core-related data, including ash content, lithology, coal body structure, and well diameter. The data is then saved to the memory according to preset data rules.

[0071] The coarse adjustment module 202, based on the principle of consistent lithology of the marker layer, adjusts the depth of the core sample according to the lithological parameters in the relevant data to obtain a second columnar section. For example, if the coal in the lithology is black, image recognition technology is used to identify the black area, and the entire lithology and corresponding depth are shifted until the uppermost part of the black area is parallel to the coal body structure, thus obtaining the second columnar section. Figure 3 As shown.

[0072] In the fine-tuning module 203, the sampling points of the rock core are moved within the depth range of the corresponding rock core segment on the second bar chart until the correlation coefficient between the ash content and natural gamma of the sampling point is the largest, and then the target location is determined.

[0073] The repositioning module 204 corrects the core depth based on the target repositioning and obtains the third columnar section after repositioning.

[0074] Furthermore, the data acquisition module 201 is also used to generate a corresponding first columnar section based on the core-related data;

[0075] The coarse adjustment module 202 is also used to generate a corresponding second bar chart after the overall adjustment;

[0076] The repositioning module 204 is also used to generate the repositioned third columnar section after correcting the core depth;

[0077] The system also includes a sorting module 205, used to arrange the first, second, and third bar charts sequentially as a single process display chart. The sorting module's function is to provide a visual display interface 208 for repositioning and adjustment, showing the initial bar chart, the coarse-adjusted bar chart, and the fine-adjusted bar chart after adjustment. Figure 5 The core samples are displayed in a specific format, thus providing an analytical basis for verifying the results of the core repositioning.

[0078] Similarly, the correlation coefficient between ash content and natural gamma is also an important reference in the entire relocation process, and therefore can be displayed simultaneously with the display chart. Specifically, a fitting module 206 is set in the system to fit the corresponding ash content and natural gamma values ​​on the first, second, and third bar charts, respectively; an output module is set to output the fitted correlation coefficient values ​​to the corresponding bar charts for display on the display interface 208.

[0079] In addition, the caliper curve and natural gamma curve corresponding to the lithology are important reference data for core analysis. Therefore, they can be output together. Specifically, a construction module 207 is set up in the system to establish the caliper curve and natural gamma curve corresponding to the lithology on the first, second, and third bar charts, respectively, as a reference for verifying the lithology, and to display them on the display interface 208. Figures 2-5 As shown, GR is the natural gamma curve, CALL is the caliber curve, and DEPTH is the depth or height.

[0080] Based on the same inventive concept, embodiments of the present invention provide an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a method for repositioning coalbed methane core depth.

[0081] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0082] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0083] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for determining the depth of coalbed methane core samples, characterized in that, The method includes: Based on core analysis and testing, relevant data from the core were obtained. Based on the principle of consistent marker lithology, the depth of the core is adjusted as a whole according to the lithological parameters in the relevant data. Move the sampling point of the core within the depth range of the corresponding core segment; If the number of core segments is within a first preset range, then by moving the sampling points within each core segment, the location with the highest correlation coefficient between the ash content and natural gamma of the sampling point is found, and that location is used as the target location. If the number of core segments is within a second preset range, then all core segments are divided into multiple regions. In each region, a core segment is randomly selected. By moving the sampling points within the core segment, the location with the highest correlation coefficient between ash content and natural gamma is found, and that location is used as the target location. The depth of the core sample is corrected based on the target repositioning.

2. The method as described in claim 1, characterized in that, The step of adjusting the overall depth of the core sample specifically includes: Based on the location of the coal body structure or the characteristics of the natural gamma curve of the core, the lithology of the core is translated until the coal seam of the lithology corresponds to the depth of the coal body structure or the depth of the coal body characteristics of the natural gamma curve.

3. The method as described in claim 1, characterized in that, The number of sampling points is greater than 3.

4. A coalbed methane core depth repositioning system, characterized in that, The system includes: The data acquisition module is used to acquire core-related data; The coarse adjustment module, based on the principle of consistent lithology of the marker layer, makes an overall adjustment to the depth of the core. The fine-tuning module moves the sampling points of the core sample within the depth range of the corresponding core segment. If the number of core segments is within a first preset range, the module moves the sampling points within each core segment to find the location with the highest correlation coefficient between ash content and natural gamma, and sets that location as the target location. If the number of core segments is within a second preset range, the module divides all core segments into multiple regions, selects a core segment within each region, moves the sampling points within that core segment to find the location with the highest correlation coefficient between ash content and natural gamma, and sets that location as the target location. The repositioning module corrects the core depth based on the target repositioning.

5. The system as described in claim 4, characterized in that, The data acquisition module is also used to generate a corresponding first columnar section based on the core-related data; The coarse adjustment module is also used to generate a corresponding second bar chart after the overall adjustment; The repositioning module is also used to generate a repositioned third columnar section after correcting the core depth; The system further includes a sorting module, used to arrange the first bar chart, the second bar chart and the third bar chart in sequence, and output them as a process display chart.

6. The system of claim 5, further comprising: The fitting module is used to fit the corresponding gray values ​​and natural gamma values ​​on the first bar chart, the second bar chart, and the third bar chart, respectively. The output module is used to output the correlation coefficient values ​​obtained from the fitting to the corresponding histograms.

7. The system according to any one of claims 5 to 6, further comprising: The construction module is used to establish wellbore curves and natural gamma curves corresponding to lithology on the first bar chart, the second bar chart, and the third bar chart, respectively, as a reference for verifying lithology.

8. An electronic device, characterized in that, The electronic device includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1 to 3.

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