A method, device, medium and product for non-destructive characterization of pore structure of rock samples

Abstract

The present application discloses a method, apparatus, medium, and product for non-destructively characterizing the pore structure of a rock sample, relating to the field of shale oil and gas. The method comprises preparing a shale sample to be tested, performing a micron CT experiment, an ultra-small angle neutron scattering experiment, and a small angle neutron scattering experiment on the shale sample to be tested, extracting a first pore volume distribution and pore volume percentage, a second pore volume distribution and pore volume percentage, and a third pore volume distribution and pore volume percentage of the shale sample to be tested, and drawing a full-scale pore size distribution curve of the shale sample to be tested based on the extracted pore volume distribution and pore volume percentage. The present application can ensure the continuity of the experimental characterization of the same sample without causing damage to the sample, and at the same time, can accurately characterize the pore structure of the sample at various scales, thereby achieving full-scale joint characterization of the pore structure of the rock sample.

Description

Technical Field

[0001] The present application relates to the field of unconventional oil and gas characterization, and in particular to a method, equipment, medium and product for non-destructive characterization of the pore structure of rock samples. Background Art

[0002] Shale oil and gas resources hold enormous potential and broad prospects for development. The pore structure of shale is crucial for evaluating, exploring, and developing shale oil and gas resources. However, current research on shale pore structure has been limited by its single-scale focus, while insufficient attention has been paid to characterizing pore structure at all scales.

[0003] Traditional intrusive pore structure research methods cause certain damage to the original structure of the sample before and after the experiment. The same sample cannot be continuously characterized for pore structures at different scales, and sample switching is required. Due to the strong anisotropy of the shale samples to be tested, this will lead to inaccurate description results. Summary of the Invention

[0004] The purpose of this application is to provide a method, equipment, medium and product for non-destructive characterization of the pore structure of rock samples, which can ensure the continuity of characterization of the same sample without causing damage to the sample. At the same time, the pore structure of the sample at all scales can be accurately characterized to achieve full-scale joint characterization of the pore structure of rock samples.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a method for non-destructively characterizing the pore structure of a rock sample, the method comprising:

[0007] preparing shale samples to be tested;

[0008] Performing a micron CT experiment on the shale sample to be tested, and extracting a first pore volume distribution and a pore volume percentage of the shale sample to be tested;

[0009] performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micron CT experiment, and extracting a second pore volume distribution and a pore volume percentage of the shale sample to be tested;

[0010] performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment, and extracting a third pore volume distribution and a pore volume percentage of the shale sample to be tested;

[0011] A full-scale pore size distribution curve of the shale sample to be tested is generated based on the first pore volume distribution and pore volume percentage, the second pore volume distribution and pore volume percentage, and the third pore volume distribution and pore volume percentage of the shale sample to be tested.

[0012] Optionally, preparing a shale sample to be tested specifically includes:

[0013] Shale to be tested with a set mass, a set diameter and a set thickness is taken from the shale core in a direction perpendicular to the base, and the shale to be tested is dried to obtain a shale sample to be tested.

[0014] Optionally, performing a micron CT experiment on the shale sample to be tested to extract a first pore volume distribution and a pore volume percentage of the shale sample to be tested specifically includes:

[0015] Performing a micrometer CT experiment on the shale sample to be tested, and capturing slices of the shale sample to be tested at various set angles;

[0016] Based on capturing slices of the shale sample to be tested at various set angles, Avizo software is used to extract the first pore volume distribution and pore volume percentage of the shale sample to be tested.

[0017] Optionally, an ultra-small angle neutron scattering experiment is performed on the shale sample to be tested after the micron CT experiment to extract a second pore volume distribution and a pore volume percentage of the shale sample to be tested, specifically including:

[0018] performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micron CT experiment, and collecting neutron scattering data of the ultra-small angle neutron scattering experiment;

[0019] The neutron scattering data of the ultra-small angle neutron scattering experiment are processed to extract the second pore volume distribution and pore volume percentage of the shale sample to be tested.

[0020] Optionally, performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment to extract a third pore volume distribution and a pore volume percentage of the shale sample to be tested specifically includes:

[0021] performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment, and collecting neutron scattering data of the small-angle neutron scattering experiment;

[0022] The neutron scattering data of the small-angle neutron scattering experiment are processed to extract the third pore volume distribution and pore volume percentage of the sample to be tested.

[0023] Optionally, the neutron scattering data of the ultra-small-angle neutron scattering experiment and the neutron scattering data of the small-angle neutron scattering experiment both include: a scattering vector and a scattering intensity.

[0024] Optionally, IGOR Pro software is used to process neutron scattering data of ultra-small angle neutron scattering experiments; IGORPro software is used to process neutron scattering data of small angle neutron scattering experiments.

[0025] In a second aspect, the present application provides a computer device comprising: 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 any one of the above-mentioned methods for non-destructive characterization of the pore structure of rock samples.

[0026] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of any one of the above-mentioned methods for non-destructive characterization of the pore structure of rock samples.

[0027] In a fourth aspect, the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the steps of any one of the above-mentioned methods for non-destructive characterization of the pore structure of rock samples.

[0028] According to the specific embodiments provided in this application, this application has the following technical effects:

[0029] The present application provides a method, device, medium and product for non-destructive characterization of the pore structure of rock samples. The method comprises the following steps: performing a micrometer CT experiment on the shale sample to extract a first pore volume distribution and pore volume percentage of the shale sample to be tested; performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micrometer CT experiment to extract a second pore volume distribution and pore volume percentage of the shale sample to be tested; and performing a small angle neutron scattering experiment on the shale sample to be tested after the ultra-small angle neutron scattering experiment to extract a third pore volume distribution and pore volume percentage of the shale sample to be tested. The method can solve the problem of easy damage to the sample during the experiment and ensure the continuity of the characterization of the same sample. By generating a full-scale pore size distribution curve of the shale sample to be tested based on the first pore volume distribution and pore volume percentage, the second pore volume distribution and pore volume percentage, and the third pore volume distribution and pore volume percentage of the shale sample to be tested, the problem of not being able to continuously characterize the pore structure of the same sample at different scales can be solved, thereby realizing full-scale joint characterization of the pore structure of the rock sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 A schematic flow chart of a method for non-destructive characterization of the pore structure of a rock sample provided in one embodiment of the present application;

[0032] Figure 2 A schematic diagram of the pore size distribution of a shale sample according to a method for non-destructive characterization of the pore structure of a rock sample provided in one embodiment of the present application;

[0033] Figure 3 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0034] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0036] In an exemplary embodiment, Figure 1 As shown, a non-destructive method for characterizing the pore structure of a rock sample is provided, comprising the following steps 100 to 104. In which:

[0037] Step 100: preparing a shale sample to be tested;

[0038] Step 101: Perform a micron CT experiment on the shale sample to be tested, and extract a first pore volume distribution and a pore volume percentage of the shale sample to be tested;

[0039] Step 102: performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micron CT experiment, and extracting a second pore volume distribution and pore volume percentage of the shale sample to be tested;

[0040] Step 103, performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment, and extracting a third pore volume distribution and a pore volume percentage of the shale sample to be tested;

[0041] Step 104 : generating a full-scale pore size distribution curve of the shale sample to be tested based on the first pore volume distribution and pore volume percentage, the second pore volume distribution and pore volume percentage, and the third pore volume distribution and pore volume percentage of the shale sample to be tested.

[0042] Implementing the above steps 100 to 104 can ensure the continuity of characterization of the same sample without damaging the sample. At the same time, the pore structure of the sample at each scale can be accurately characterized to achieve full-scale joint characterization of the pore structure of the rock sample.

[0043] In another exemplary embodiment of the present application, in order to ensure the effectiveness of the experiment, the target shale needs to be prepared accordingly.

[0044] For example, the method for preparing shale samples is as follows:

[0045] A certain mass of shale perpendicular to the basement direction is taken from the target shale core sample, and the shale is formed into circular slices with a diameter of 2.0 cm and a thickness of 0.5 mm. The prepared slices are further dried to obtain the shale sample to be tested. The drying process is carried out in a drying oven at a temperature of 70°C for 24 hours.

[0046] In another exemplary embodiment of the present application, in order to characterize the pore structure of a shale sample, a micron CT experiment is performed on the shale sample to extract the first pore volume distribution and pore volume percentage of the shale sample to be tested, wherein the micron CT experiment is performed on a general-purpose Nanotom SX X-ray scanner in the United States.

[0047] In practical applications, the micron CT experimental process for shale samples includes:

[0048] The first step is to clean the surface of the shale sample to be tested and remove surface contaminants to avoid interference with the scanning results.

[0049] The second step is to fix the shale sample to be tested and place it vertically into the micron CT scanning device.

[0050] In the third step, during the scanning process, the shale sample to be tested remains stationary, and the X-ray source and detector are rotated to capture slices of the shale sample at various angles. During this process, the micron CT scanning voltage is 60kV, the experimental temperature is 20°C, and the single exposure time is 2 seconds.

[0051] The fourth step is to import the TIFF format image sequence generated by micron CT of the shale sample to be tested into AVIZO (visualization software for earth and geological sciences, etc.). After setting the correct resolution and pixel size, data preprocessing is performed to make the data volume clearer. Then, the sample is reconstructed and visualized in three dimensions, and the pore volume distribution and volume percentage of the shale sample with a pore size greater than 2μm are extracted.

[0052] In another exemplary embodiment of the present application, in order to comprehensively characterize the pore structure of a shale sample, in this embodiment, an ultra-small-angle neutron scattering experiment is performed on the shale sample to be tested to extract the second pore volume distribution and pore volume percentage of the shale sample to be tested, wherein the ultra-small-angle neutron scattering experiment is performed using a general-purpose SANS (small-angle neutron scattering) (GP-SANS) instrument of the Oak Ridge National Laboratory (ORNL) in the United States.

[0053] In actual experiments, the ultra-small angle neutron scattering experimental process of the shale sample to be tested specifically includes:

[0054] The first step is to place the sample that has completed the micron CT experiment on the sample stage of the ultra-small angle neutron scattering equipment, ensure that the sample is placed correctly and fixed in the center position, and adjust the sample position and angle to ensure that the neutron beam can accurately irradiate the sample.

[0055] The second step is to adjust the neutron source so that the neutron wavelength Scattering intensity Q value range

[0056] The third step is to start the ultra-small-angle neutron scattering equipment, begin the ultra-small-angle neutron scattering experiment, and collect neutron scattering data.

[0057] The fourth step is to use IGOR PRO (data analysis and drawing software) to analyze and process the scattering data to obtain the sample's scattering vector, analyze its pore structure and pore size distribution information, and extract the pore volume distribution and volume percentage of the shale sample with a pore size of 20nm to 2μm.

[0058] In another exemplary embodiment of the present application, in order to more comprehensively characterize the pore structure of the shale sample, in this embodiment, a small-angle neutron scattering experiment is performed on the shale sample to be tested to extract the third pore volume distribution and pore volume percentage of the shale sample to be tested, wherein the small-angle neutron scattering experiment is performed using the general-purpose SANS (small-angle neutron scattering) (GP-SANS) instrument of the Oak Ridge National Laboratory (ORNL) in the United States.

[0059] In actual experiments, the small-angle neutron scattering experiment process for the shale sample to be tested specifically includes:

[0060] The first step is to place the sample that has undergone ultra-small-angle neutron scattering on the sample stage of the small-angle neutron scattering equipment, ensure that the sample is placed correctly and fixed in the center position, and adjust the sample position and angle to ensure that the neutron beam can accurately irradiate the sample.

[0061] The second step is to adjust the neutron source so that the neutron wavelength is and Scattering intensity Q value range

[0062] The third step is to start the small-angle neutron scattering equipment, start the small-angle neutron scattering experiment, and collect the neutron scattering data.

[0063] The fourth step is to use IGOR PRO software to analyze and process the scattering data to obtain the sample's scattering vector, analyze its pore structure and pore size distribution information, and extract the pore volume distribution and volume percentage of the pore size of the shale sample to be tested with a pore size of 0 to 20 nm.

[0064] Based on the above description, the first pore volume distribution and pore volume percentage, the second pore volume distribution and pore volume percentage, and the third pore volume distribution and pore volume percentage of the extracted shale sample to be tested are plotted to obtain the full-scale pore size distribution curve of the shale sample to be tested, such as Figure 2 shown.

[0065] In this application, small-angle neutron scattering, ultra-small-angle neutron scattering and micron CT technology are used to jointly characterize the pore structure of rock samples at all scales. It is the first to propose the use of a combination of neutron scattering and CT technology to characterize the pore structure of rock samples. This method has the following advantages over traditional methods, such as high-pressure mercury injection and gas adsorption: First, there is no damage to the sample during the experiment, and the same sample can be experimented continuously; second, the neutron scattering experiment and the CT experiment can obtain all the pores (connected pores and isolated pores) of the shale sample at the corresponding scale, thereby making the characterization results more accurate.

[0066] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Figure 3As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O) and a communication interface. The processor, memory and input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and computer program in the non-volatile storage medium. The database of the computer device is used to store data to be processed. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for non-destructive characterization of the pore structure of a rock sample is implemented.

[0067] Those skilled in the art will understand that Figure 3 The structure shown in the figure is merely a block diagram of a portion of the structure related to the solution of the present application and does not constitute a limitation on the computer device to which the solution of the present application is applied. A specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor implements the steps of the above-mentioned method embodiments when executing the computer program.

[0068] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program. When the computer program is executed by a processor, the steps in the above-mentioned method embodiments are implemented.

[0069] In an exemplary embodiment, a computer program product is provided, including a computer program. When the computer program is executed by a processor, the steps in the above method embodiments are implemented.

[0070] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0071] Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0072] The databases involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processors involved in the various embodiments provided herein may include, but are not limited to, general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic units, data processing logic units based on quantum computing, and the like.

[0073] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0074] This document uses specific examples to illustrate the principles and implementation methods of this application. The description of the above examples is only intended to help understand the method and core concept of this application. At the same time, for those skilled in the art, based on the concept of this application, there may be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A non-destructive method for characterizing the pore structure of rock samples, characterized in that: The non-destructive method for characterizing the pore structure of a rock sample comprises: preparing shale samples to be tested; Performing a micron CT experiment on the shale sample to be tested, and extracting a first pore volume distribution and a pore volume percentage of the shale sample to be tested; performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micron CT experiment, and extracting a second pore volume distribution and a pore volume percentage of the shale sample to be tested; performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment, and extracting a third pore volume distribution and a pore volume percentage of the shale sample to be tested; A full-scale pore size distribution curve of the shale sample to be tested is generated based on the first pore volume distribution and pore volume percentage, the second pore volume distribution and pore volume percentage, and the third pore volume distribution and pore volume percentage of the shale sample to be tested.

2. The non-destructive method for characterizing the pore structure of a rock sample according to claim 1, characterized in that: Prepare the shale sample to be tested, specifically including: Shale to be tested with a set mass, a set diameter and a set thickness is taken from the shale core in a direction perpendicular to the base, and the shale to be tested is dried to obtain a shale sample to be tested.

3. The non-destructive method for characterizing the pore structure of rock samples according to claim 1, characterized in that: The performing of a micron CT experiment on the shale sample to be tested to extract a first pore volume distribution and a pore volume percentage of the shale sample to be tested specifically includes: Performing a micrometer CT experiment on the shale sample to be tested, and capturing slices of the shale sample to be tested at various set angles; Based on the captured slices of the shale sample to be tested at various set angles, the Avizo software is used to extract the first pore volume distribution and pore volume percentage of the shale sample to be tested.

4. The non-destructive method for characterizing the pore structure of a rock sample according to claim 1, wherein: The ultra-small angle neutron scattering experiment is performed on the shale sample to be tested after the micron CT experiment to extract the second pore volume distribution and pore volume percentage of the shale sample to be tested, specifically including: performing an ultra-small angle neutron scattering experiment on the shale sample to be tested after the micron CT experiment, and collecting neutron scattering data of the ultra-small angle neutron scattering experiment; The neutron scattering data of the ultra-small angle neutron scattering experiment are processed to extract the second pore volume distribution and pore volume percentage of the shale sample to be tested.

5. The non-destructive method for characterizing the pore structure of a rock sample according to claim 1, characterized in that: The step of performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment to extract the third pore volume distribution and pore volume percentage of the shale sample to be tested specifically includes: performing a small-angle neutron scattering experiment on the shale sample to be tested after the ultra-small-angle neutron scattering experiment, and collecting neutron scattering data of the small-angle neutron scattering experiment; The neutron scattering data of the small-angle neutron scattering experiment are processed to extract the third pore volume distribution and pore volume percentage of the shale sample to be tested.

6. The method for non-destructive characterization of the pore structure of a rock sample according to claim 4 or claim 5, characterized in that: The neutron scattering data of ultra-small-angle neutron scattering experiments and the neutron scattering data of small-angle neutron scattering experiments both include: scattering vector and scattering intensity.

7. The method for non-destructive characterization of pore structure of rock samples according to claim 4 or claim 5, characterized in that: IGOR Pro software was used to process the neutron scattering data of ultra-small-angle neutron scattering experiments; IGOR Pro software was used to process the neutron scattering data of small-angle neutron scattering experiments.

8. A computer device comprising: 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 method for non-destructive characterization of the pore structure of a rock sample according to any one of claims 1 to 7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for non-destructive characterization of the pore structure of a rock sample according to any one of claims 1 to 7 is implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method for non-destructive characterization of the pore structure of a rock sample according to any one of claims 1 to 7 is implemented.

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