Coal bed gas core depth homing method, system and equipment

Abstract

The invention discloses a coal bed gas rock core depth homing method, system and equipment, and the method comprises the steps: obtaining the related data of a rock core based on rock core analysis and assay; based on a marker bed lithology consistency principle, the depth of the rock core is integrally adjusted according to lithology parameters in related data; moving the sampling point of the rock core in the depth range of the corresponding rock core section until the correlation coefficient between the ash content of the sampling point and the natural gamma is maximum, and determining as a target homing; and correcting the depth of the core based on the target homing. Accurate sampling points in coal core analysis and assay can be found, so that the real horizon and depth of the core can be recovered.

Description

Technical Field

[0001] The present invention relates to the technical field of coalbed methane geological analysis, and in particular to a coalbed methane core depth homing method, system and equipment. Background Art

[0002] Conventional core analysis and testing depth homing can be completed by simply translating the core analysis data of the marker layer and the logging depth difference. In the prior art, one method is to establish a relationship between the physical parameters of the core analysis and the logging data, and the position with the largest correlation coefficient is the target homing depth. Another method is to compare the natural gamma test data of the core with the logging gamma curve, and translate the whole to find the target homing depth.

[0003] Compared with sandstone, the reservoir coal is brittle, and its coring process is generally based on ropes. The diameter of the coal core is relatively small, and the well wall will collapse if the drilling pressure is not careful. Moreover, most of the coal cores are broken after coming out of the barrel. At this time, it is difficult for the experimenters to obtain the accurate depth of the plunger sample when sampling and analyzing the coal rock. Therefore, the coal core analysis report generally attributes the analysis value of a certain point to a certain section of the sample, rather than a conventional depth, which leads to the uncertainty of the location of the coal core analysis sampling point in the sample section. Therefore, the depth homing method of coalbed methane cores cannot be completely performed according to the conventional method. Summary of the invention

[0004] The embodiments of the present invention provide a method, system, equipment and medium for tracing the depth of coalbed methane cores, which at least partially solve the technical problem of uncertain position of sampling points in sample segments in coal core analysis and testing in the prior art. By adjusting the sampling points separately after the overall translation of the lithology, it is possible to find accurate sampling points in coal core analysis and testing.

[0005] In the first aspect, in order to solve the above technical problems, the embodiments of the present invention provide the following technical solutions:

[0006] A coalbed methane core depth tracing method, comprising:

[0007] Based on core analysis and testing, obtain relevant data of the core;

[0008] Based on the principle of consistent lithology of the marker layer, the depth of the above cores is adjusted overall according to the lithology parameters in the above related data;

[0009] The sampling point of the core is moved within the depth range of the corresponding core section until the correlation coefficient between the ash content and the natural gamma at the sampling point is the largest, and the target position is determined;

[0010] The depth of the core is corrected based on the target position.

[0011] Optionally, the step of overall adjusting the depth of the core specifically includes:

[0012] According to the coal body structure position or natural gamma curve characteristics 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.

[0013] Optionally, the above step of determining as target homing specifically includes:

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

[0015] By moving the sampling points in each core section, the position where the correlation coefficient between the ash content and natural gamma of the above sampling points is the largest is found, and the above position is used as the target position.

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

[0017] All core sections are divided into multiple areas. A core section is selected in each of the above areas. The position with the largest correlation coefficient between ash content and natural gamma is found by moving the sampling points in the above core section, and the above position is used as the target position.

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

[0019] In a second aspect, a coalbed methane core depth homing system is provided, comprising:

[0020] A data acquisition module, used to acquire core-related data;

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

[0022] A fine adjustment module is used to move the sampling point of the core within the depth range of the corresponding core section until the correlation coefficient between the ash content and the natural gamma of the sampling point is the largest, and the target position is determined;

[0023] The homing module corrects the core depth based on the above target homing.

[0024] Optionally, the data acquisition module is further used to generate a corresponding first histogram according to the core-related data;

[0025] The above-mentioned coarse adjustment module is further used to generate a corresponding second histogram after the above-mentioned overall adjustment;

[0026] The above-mentioned homing module is also used to generate a third histogram after the core depth is corrected;

[0027] The system also includes: a sorting module, which is used to arrange the first bar graph, the second bar graph and the third bar graph in sequence and output them as a process display chart.

[0028] Optionally, the above system further includes:

[0029] A fitting module, used for fitting the corresponding ash values ​​and natural gamma values ​​on the first histogram, the second histogram and the third histogram respectively;

[0030] The output module is used to output the correlation coefficient values ​​obtained by the above fitting to the corresponding bar graphs.

[0031] Optionally, the above system further includes:

[0032] The construction module is used to respectively establish a wellbore curve and a natural gamma curve corresponding to the lithology on the first histogram, the second histogram and the third histogram as a reference for checking the lithology.

[0033] In a third aspect, an electronic device is provided, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps corresponding to the method of the first aspect when executing the computer program.

[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 the embodiment of the present invention, the principle of consistency of the lithology of the marker layer is first used, that is, the lithology depth is roughly adjusted overall by comparing the coal body structure and the position of the characteristic point of the natural gamma curve; then, according to the corresponding relationship between the positive correlation between ash content and natural gamma, the depth of individual sampling points is fine-tuned, and the position with the maximum correlation coefficient between ash content and natural gamma is selected as the target position. In this way, the accurate sampling point in the coal core analysis and testing is found, so as to restore the real layer and depth of the core. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A flow chart of a coalbed methane core depth homing method provided by the present invention;

[0038] Figure 2 is the first bar graph in the present invention;

[0039] Figure 3 is the second bar graph in the present invention;

[0040] Figure 4 is the third bar graph of the present invention;

[0041] Figure 5 It is a display diagram in the present invention;

[0042] Figure 6 A structural schematic diagram of a coalbed methane core depth homing system provided by the present invention. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0044] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0046] In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood 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 the present application, rather than limitations of the technical solutions of the present application. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments may be combined with each other.

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

[0049] First, the lithology depth is shifted as a whole by comparing the coal structure and the position of the characteristic points of the natural gamma curve; then, according to the corresponding relationship between the ash content and the natural gamma, the depth of individual sample points is fine-tuned, and the position with the maximum correlation coefficient between the ash content and the natural gamma is selected as the target position. In this way, the accurate sampling point in the coal core analysis and testing is found, so as to restore the real layer and depth of the core.

[0050] Embodiment 1:

[0051] In an embodiment of the present invention, there is provided Figure 1 A method for core depth tracing of coalbed methane is shown, the method comprising steps S101 to S104:

[0052] Step S101, obtaining core-related data based on core analysis and testing;

[0053] It should be noted that core analysis and testing mainly include microscopic technology and spectroscopy technology, etc., and the relevant data of the core is obtained from them. The relevant data specifically include the ash content, lithology, coal structure, well diameter curve and natural gamma curve of the core.

[0054] Step S102, based on the principle of consistency of marker layer lithology, the depth of the core is adjusted overall according to the lithology parameters in the relevant data.

[0055] It should be noted that the principle of consistent lithology of the marker layer means that when returning the cores, the cores taken from the same stratum are returned to their original positions to ensure the accuracy and reliability of the core analysis results. After the initial sampling, the sampled cores may be deviated or missing due to geological factors, drilling technology factors, sampling factors, etc. Therefore, a rough adjustment is first performed, specifically: according to the coal structure position of the core or the natural gamma curve characteristics, the lithology of the core is translated until the coal layer of the lithology corresponds to the depth of the coal structure or the depth of the coal characteristics of the natural gamma curve.

[0056] Among them, the coal body structure is broken coal, which can reflect the location of the coal seam in the lithology, such as Figure 2 As shown, the position of the crushed coal can be adjusted according to the Figure 2 The lithology of the coal seam in the middle core corresponds to the crushed coal, and we can get Figure 3 .in addition, Figure 2 The black area is coal, the brick area is limestone, and the rest is mudstone. Different minerals have different natural gamma radiation intensities. Based on the comparison of intensity characteristics, the approximate location of the coal seam can be found and rough adjustments can be made.

[0057] Step S103, moving the sampling point of the core within the depth range of the corresponding core section until the correlation coefficient between the ash content and the natural gamma at the sampling point is the maximum, and determining it as the target position;

[0058] In this embodiment, the rough adjustment is only performed based on the rough analysis results, and there is still a deviation after the adjustment, such as Figure 3 As shown, fine-tuning is needed to further improve the accuracy. Therefore, the ash data obtained from core analysis is used for repositioning, that is, based on the principle of positive correlation between ash and natural gamma, the position of the sampling point is changed within the height range of the corresponding core section until the position with the largest correlation coefficient between ash and natural gamma is found, thereby obtaining Figure 4 .

[0059] Specifically, when the number of core segments is within the first preset range, for example, when the number of core segments is less than 20, the position where the ash content of the sampling point has the largest correlation coefficient with the natural gamma is found by moving the sampling points in each core segment, and all core segments are corrected based on the position and core deviation. In other words, because the number of core segments to be processed is small, the sampling points of each core segment can be found by changing their positions to ensure the accuracy of fine-tuning. The number of ash test points needs to be greater than 3 to avoid the problem of low depth homing accuracy.

[0060] When the number of core segments is within the second preset range, for example, when it is greater than 20, all core segments are divided into multiple regions, and one core segment is selected in each region. By moving the sampling points in the core segment, the position with the largest correlation coefficient between ash content and natural gamma is found, and all core segments in the region are corrected based on the position and the deviation of the core. In other words, when there are too many test point data selected, it is a heavy burden to search one by one. Based on different height ranges, the geology with large differences can be divided into different regions, and the deviation of a core segment in each region is calculated, and then all core segments in the region are adjusted according to the deviation, thereby reducing the calculation burden.

[0061] It should be noted that the sampling point can be changed in a random manner, by randomly selecting sampling points at multiple positions, calculating the correlation coefficient between ash content and natural gamma, and selecting the position with the maximum correlation coefficient as the target position. The more sampling points there are, the more accurate the target position is. Of course, other methods can also be selected to set the sampling points, which are not limited here.

[0062] Step S104, correcting the core depth based on the target homing.

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

[0064]

[0065]

[0066] Table 1

[0067] In the embodiment of the present invention, the principle of consistent lithology of the marker layer is used to compare the coal body structure and the position of the characteristic points of the natural gamma curve to make a rough adjustment to the lithology depth as a whole; then, according to the corresponding relationship between the positive correlation between ash content and natural gamma, the depth of individual sampling points is fine-tuned, and the position with the maximum correlation coefficient between ash content and natural gamma is selected as the target position. In this way, the accurate sampling point in the coal core analysis and testing is found, so as to restore the real layer and depth of the core.

[0068] Embodiment 2:

[0069] Based on the same inventive concept, the embodiment of the present invention provides a coalbed methane core depth homing system, such as Figure 6 As shown, including:

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

[0071] The coarse adjustment module 202 adjusts the depth of the core as a whole based on the principle of consistency of the lithology of the marker layer and the lithology parameters in the relevant data to obtain a second histogram; for example, if the coal is black in the lithology, the black area is identified by using image recognition technology, and the entire lithology and the corresponding depth are translated until the uppermost end of the black area is parallel to the coal body structure to obtain a second histogram, such as Figure 3 shown.

[0072] The fine adjustment module 203 moves the sampling point of the core within the depth range of the corresponding core section on the second histogram until the correlation coefficient between the ash content and the natural gamma at the sampling point is the largest, and determines it as the target position;

[0073] The homing module 204 corrects the core depth based on the target homing to obtain a third histogram after homing.

[0074] Furthermore, the data acquisition module 201 is also used to generate a corresponding first histogram according to the core-related data;

[0075] The coarse adjustment module 202 is further used to generate a corresponding second histogram after the overall adjustment;

[0076] The homing module 204 is also used to generate a third histogram after the core depth is corrected;

[0077] The system further includes: a sorting module 205, which is used to arrange the first bar graph, the second bar graph and the third bar graph in order and output them as a process display diagram. The function of the sorting module is to provide a visual display interface 208 for homing adjustment, that is, to arrange the initial bar graph, the rough adjustment bar graph and the fine adjustment bar graph in a row after adjustment. Figure 5 It is displayed in the form of a graph, thus providing an analytical basis for the verification of the core retrieval results.

[0078] Similarly, the correlation coefficient between ash content and natural gamma is also an important reference in the whole homing process, so it can be displayed together with the display chart. Specifically, a fitting module 206 is set in the system to fit the corresponding ash content value and natural gamma value on the first bar graph, the second bar graph and the third bar graph respectively; an output module is set to output the correlation coefficient values ​​obtained by the fitting to the corresponding bar graphs respectively, and display them on the display interface 208.

[0079] In addition, the borehole diameter curve and natural gamma curve corresponding to the lithology are important reference data for core analysis. Therefore, they can be output together. In detail, a construction module 207 is set in the system to respectively establish the borehole diameter curve and natural gamma curve corresponding to the lithology on the first bar graph, the second bar graph and the third bar graph as references for checking the lithology, and display them on the display interface 208. Figure 2 to Figure 5 As shown, GR is the natural gamma curve, CALL is the wellbore curve, and DEPTH is the depth or height.

[0080] Based on the same inventive concept, an embodiment of the present invention provides 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, a method for tracing the depth of a coalbed methane core is implemented.

[0081] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0082] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0083] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for core depth homing of coalbed methane, characterized in that: The method comprises: Based on core analysis and testing, obtain relevant data of the core; Based on the principle of consistency of marker layer lithology, the depth of the core is adjusted overall according to the lithology parameters in the relevant data; The sampling point of the core is moved within the depth range of the corresponding core section until the correlation coefficient between the ash content and the natural gamma at the sampling point is the largest, and the target position is determined; The depth of the core is corrected based on the target homing.

2. The method according to claim 1, characterized in that The step of overall adjusting the depth of the core specifically includes: According to the coal body structure position or natural gamma curve characteristics 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 according to any one of claims 1 to 2, characterized in that: The step of determining the target homing specifically includes: When the number of core segments is within a first preset range; By moving the sampling points in each core section, the position where the correlation coefficient between the ash content and the natural gamma of the sampling point is the largest is found, and the position is used as the target position.

4. The method according to claim 3, characterized in that When the number of core segments is within a second preset range; The method further comprises: All core sections are divided into multiple areas, and a core section is selected in each of the areas. The position with the largest correlation coefficient between ash content and natural gamma is found by moving the sampling points in the core section, and the position is used as the target position.

5. The method according to claim 1, characterized in that The number of sampling points is greater than 3.

6. A coalbed methane core depth homing system, characterized in that: The system comprises: A data acquisition module, used to acquire core-related data; A coarse adjustment module adjusts the depth of the core as a whole based on the principle of consistent lithology of the marker layer; A fine adjustment module is used to move the sampling point of the core within the depth range of the corresponding core section until the correlation coefficient between the ash content and the natural gamma of the sampling point is the largest, and the target position is determined; A homing module is used to correct the core depth based on the target homing.

7. The system according to claim 6, characterized in that The data acquisition module is further used to generate a corresponding first histogram according to the core-related data; The coarse adjustment module is further used to generate a corresponding second histogram after the overall adjustment; The homing module is also used to generate a third histogram after the core depth is corrected; The system further comprises: a sorting module for arranging the first bar graph, the second bar graph and the third bar graph in sequence, and outputting the sequence as a process display diagram.

8. The system of claim 7, further comprising: A fitting module, used for fitting the corresponding ash values ​​and natural gamma values ​​on the first histogram, the second histogram and the third histogram respectively; The output module is used to output the correlation coefficient values ​​obtained by the fitting to the corresponding bar graphs.

9. The system according to any one of claims 7 to 8, further comprising: A construction module is used to establish a wellbore curve and a natural gamma curve corresponding to the lithology on the first histogram, the second histogram and the third histogram, respectively, as a reference for checking the lithology.

10. An electronic device, characterized in that: The electronic device comprises: a memory, a processor, and a computer program stored in the memory and executable on the processor, and the processor implements any one of the method steps described in claims 1 to 5 when executing the computer program.

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