A classification method, system, medium, equipment and terminal for fine-grained sediment particles

Abstract

The present invention belongs to the technical field of oil and gas resource exploration and discloses a classification method, system, medium, equipment, and terminal for fine-grained sedimentary particles. Based on multi-scale, multi-field scanning electron microscopy identification technology, the microstructural images of fine-grained sedimentary rocks are spliced ​​and identified using FE-SEM. The identified images are then grayscale processed using ImageJ software to determine the microstructural characteristic parameters of the fine-grained sedimentary particles. Nanoindentation experiments are used to measure the micromechanical properties of the fine-grained sedimentary particles, including hardness and elastic modulus. A five-unit characterization method is constructed using particle size, flatness, angularity, elastic modulus, and hardness to determine the characteristics of the fine-grained sedimentary particles. Based on the principle of the five basic properties of fine-grained sedimentary particles, the combination types of fine-grained sedimentary particles are classified. The novel image analysis technology of the present invention is more comprehensive and intuitive than local observation under a scanning electron microscope, providing new ideas for quantitative characterization and qualitative analysis of microstructures.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas resource exploration, and in particular relates to a classification method, system, medium, equipment and terminal for fine-grained sediment particles. Background Art

[0002] Currently, fine-grained sedimentary rocks are considered to be important source rocks for unconventional oil and gas resources. They are characterized by fine grain size, complex structure, and strong heterogeneity. The formation of fine-grained sedimentary rocks undergoes geological evolution processes such as sedimentation and diagenesis. Their macroscopic structural characteristics and microscopic morphological features are far more complex than those of other rocks. The grain size of fine-grained rocks is small and difficult to accurately identify with the naked eye; the sedimentary structural characteristics of fine-grained sedimentary rocks vary greatly, and diagenesis has strongly transformed the sedimentary grains; even fine-grained rocks with similar macroscopic structural characteristics have ever-changing microscopic morphological characteristics. Therefore, relying solely on macroscopic classification methods (such as the "three-terminal" classification method of mineral composition, color structural classification method, and genetic classification method) cannot fully characterize the true properties of fine-grained sedimentary rocks.

[0003] The macroscopic structural characteristics and color properties of fine-grained rocks are the comprehensive external manifestations of their microstructure. The macroscopic properties of rocks are controlled by their microstructural characteristics. Systematic research on the microstructure of fine-grained particles is a process from internal mechanisms to external manifestations.

[0004] Through the above analysis, the problems and defects of the existing technology are: due to the small particle size of fine-grained rocks and the diverse variations in sedimentary structural characteristics, the current reliance on the macroscopic mineral composition "three-end member" classification method, color structure classification method, and genetic classification method cannot fully characterize the true properties of fine-grained sedimentary rocks. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a method, system, medium, equipment and terminal for classifying fine-grained deposited particles, and in particular relates to a method, system, medium, equipment and terminal for classifying fine-grained deposited particles based on morphological characteristics and micromechanical properties.

[0006] The present invention is achieved by providing a method for classifying fine-grained sedimentary particles, which comprises: based on multi-scale and multi-viewing field scanning electron microscope identification technology, performing FE-SEM splicing and identification on the microstructure image of fine-grained sedimentary rock, grayscale processing the identified image using ImageJ software, and determining the microstructure characteristic parameters of the fine-grained sedimentary particles; measuring the micromechanical properties of hardness and elastic modulus of fine-grained sedimentary particles using nanoindentation experiments; comprehensively analyzing the morphology of fine-grained sedimentary particles and rock mechanics characteristics, based on the force and deformation displacement of particles and particle geometric parameters, constructing a five-unit characterization method using particle size, flatness, angularity, elastic modulus and hardness to determine the characteristics of fine-grained sedimentary particles; and classifying the combination types of fine-grained sedimentary particles according to the principle of the five-unit basic properties of fine-grained sedimentary particles.

[0007] Furthermore, the method for classifying fine-grained sediment particles comprises the following steps:

[0008] Step 1: Based on the multi-scale and multi-view scanning electron microscopy identification technology, combined with ImageJ software, the microscopic morphological characteristics (particle size and shape characteristics) of the fine-grained sediment particles are determined;

[0009] Step 2: using nanoindentation experiments to determine the micromechanical properties of fine-grained sediment particles;

[0010] Step three, quantitative characterization of the microstructural characteristics of fine-grained sedimentary particles: a five-unit characterization method is constructed using the particle size, flatness, angularity, elastic modulus and hardness of the particles to determine the characteristics of the fine-grained sedimentary particles; based on the principle of the basic properties of the five units of particles, the combination types of fine-grained sedimentary particles are divided according to the normalized parameters of the five units of fine-grained sedimentary particles.

[0011] Furthermore, the quantitative characterization of the microstructural characteristics of the fine-grained sediment particles in step 1 includes:

[0012] The microstructural characteristics of fine-grained sedimentary rocks were statistically analyzed with the help of multi-scale and multi-viewing field micropore identification technology. A field emission environmental scanning electron microscope was used to continuously move the end to end to take photos of the shale microstructure. The scanning electron microscope photos were stitched together to obtain an image reflecting the overall microscopic characteristics of the sedimentary rocks. The identified images were grayscale processed using ImageJ software to determine the multi-scale micropore structural characteristics.

[0013] Furthermore, in step 1, the identified image is imported into ImageJ image processing software to obtain a digital image in black and white tones, and the microstructural characteristic parameters of the particles are characterized by using ImageJ software, specifically including:

[0014] (1) Grayscale conversion: import the target image into the software and perform grayscale conversion on the image;

[0015] (2) Grayscale threshold setting: adjust the image threshold according to the grayscale value of the image so that the image shows the complete geometric shape of the particle size, keep the threshold concentrated in a stable range, and extract the particles according to the threshold;

[0016] (3) Automatic denoising: removing noise from the image after threshold processing by manually correcting the image or filtering and smoothing the image;

[0017] (4) Acquisition of geometric parameters: Calculate the geometric parameters of the particle objects, including the centroid coordinates (X, Y), axis length ratio, area, perimeter, equivalent ellipse perimeter, and convexity, and perform calibration counting;

[0018] (5) Export data: Export and transform data, save all data output in an Excel spreadsheet, and convert the measurement results to obtain the true geometric information of the particles.

[0019] Furthermore, in step one, the microscopic morphological characteristics of the fine-grained sediment particles include particle size, flatness, and angularity, and the mechanical property characteristics include elastic modulus, hardness, and creep.

[0020] Based on the multi-scale and multi-viewing field scanning electron microscopy identification technology and combined with ImageJ software, the particle size and particle size distribution of shale sample particles were statistically analyzed to determine the particle size distribution characteristics of shale sample particles.

[0021] The mathematical model is used to quantitatively characterize the morphological characteristic parameters of fine-grained sediment particles and determine the shape of fine-grained sediment particles. Among them, the particle flatness and perimeter angularity index of the sample are consistent with the logarithmic normal distribution H1:X~LN(μ,σ 2 ) and normal distribution H0:X~N(μ,σ 2 ) characteristics.

[0022] Furthermore, in step 3, according to the principle of the basic properties of the five units of particles, each parameter is dimensionlessly processed by normalization to achieve proportional scaling of the data, so that the data becomes a relative value relationship;

[0023] Among them, the normalization formula is:

[0024]

[0025] Where, X norm is the normalized data, X is the original data, X max and X min are the maximum and minimum values ​​of the original data respectively.

[0026] According to the normalized parameters of the five units of fine-grained sedimentary particles, the combination types of shale fine particles are divided into the following six categories: Type 1: particle size + angularity type; Type 2: flatness + angularity type; Type 3: flatness + angularity + elastic modulus + hardness type; Type 4: elastic modulus + hardness type; Type 5: angularity + elastic modulus + hardness type; Type 6: particle size + angularity + elastic modulus type.

[0027] Another object of the present invention is to provide a classification system for fine-grained deposited particles using the classification method for fine-grained deposited particles, the classification system for fine-grained deposited particles comprising:

[0028] Fine-grained sediment particle structure characterization module, which is used to construct a five-element characterization method using particle size, flatness, angularity, elastic modulus, and hardness to characterize fine-grained sediment particles;

[0029] The module for determining the micromorphology and mechanical properties of fine-grained sediment particles is used to determine the particle size and shape characteristics of fine-grained sediment particles based on multi-scale and multi-viewing field scanning electron microscopy identification technology combined with ImageJ software, and to determine the micromechanical properties of fine-grained sediment particles using nanoindentation experiments;

[0030] The fine-grained sediment particle type classification module is used to classify the combination types of fine-grained sediment particles based on the principle of the basic properties of the five units of particles and the normalized parameters of the five units of fine-grained sediment particles.

[0031] Another object of the present invention is to provide a computer device, which includes a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method for classifying fine-grained deposited particles.

[0032] Another object of the present invention is to provide a computer-readable storage medium storing a computer program, which, when executed by a processor, causes the processor to perform the steps of the method for classifying fine-grained deposited particles.

[0033] Another object of the present invention is to provide an information data processing terminal, which is used to implement the classification system of fine-grained sediment particles.

[0034] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0035] First, the present invention provides a classification method for fine-grained sedimentary particles based on morphological characteristics and micromechanical properties. The microstructural characteristics of fine-grained sedimentary rocks are statistically analyzed with the help of multi-scale and multi-view micropore identification technology. A field emission environmental scanning electron microscope is used to continuously move and take photos of the shale microstructure, and the photos are stitched together in sequence. After software identification and recognition processing (ImageJ), the multi-scale micropore structural characteristics can be observed in all aspects. ImageJ image processing software can easily obtain basic geometric parameters such as the number, perimeter, area, and length and diameter of particles, and can also segment, count, and classify target images.

[0036] The microstructure of fine-grained sedimentary particles determines the physical and chemical properties of fine-grained rocks and controls the macroscopic characteristics of fine-grained rocks. The characteristics of fine-grained sedimentary particles include both morphological characteristics and their rock mechanical properties. The microscopic morphological characteristics of fine-grained sedimentary particles mainly include the particle size, shape and roughness, while the mechanical properties are composed of elastic modulus, hardness, creep, etc. The present invention integrates the morphology of fine-grained sedimentary particles and the rock mechanical characteristics, and constructs a "five-unit" characterization method to describe the characteristics of fine-grained sedimentary particles from the perspective of particle force and deformation displacement, and particle geometric parameters. The "five-unit" characteristics of particles are particle size, flatness, angularity, elastic modulus and hardness. The present invention adopts the equivalent diameter of circle area D S As the diameter of the particles, the two-dimensional parameter perimeter angularity index is used to finely characterize the angularity of fine-grained sediment particles, and a mathematical model is used to accurately and quantitatively characterize the shape of the particles, thereby realizing the classification of fine-grained sediment particles.

[0037] Second, the five-unit characterization method for fine-grained sedimentary particles allows for the classification of different fine-grained sedimentary particles. Based on characteristic parameters such as particle size, flatness, angularity, elastic modulus, and hardness, particles are divided into different assemblages, enabling a better understanding of the genesis and evolution of fine-grained sedimentary rocks. Furthermore, this classification method has applications in a variety of fields, such as petroleum exploration and soil science.

[0038] This classification method divides the types of fine-grained sedimentary rock particles from the perspective of mechanics and morphology, which is innovative in classification methods. The classification results can restore the environmental and diagenetic evolution stress and structural conditions during the sedimentary period, which has important scientific significance for paleoenvironmental research and diagenetic evolution research. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0040] Figure 1 is a flow chart of a method for classifying fine-grained sediment particles provided by an embodiment of the present invention;

[0041] Figure 2A This is a schematic diagram of determining the viewing angle magnification provided by an embodiment of the present invention;

[0042] Figure 2B is a photograph taken according to an embodiment of the present invention;

[0043] Figure 2C Schematic diagram of the multi-scale and multi-view stitching technology provided by an embodiment of the present invention;

[0044] Figure 2D is a schematic diagram of particle identification provided by an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of a quantitative characterization technique for particle geometric features based on multi-scale, multi-viewing domains and ImageJ software provided by an embodiment of the present invention;

[0046] Figure 4 is a schematic diagram of fine particle statistical diameter provided by an embodiment of the present invention;

[0047] Figure 5 is a schematic diagram of particle shape parameters provided by an embodiment of the present invention;

[0048] Figure 6 Schematic diagram of the average particle size of terrestrial fine-grained sediment particles provided by an embodiment of the present invention;

[0049] Figure 7 This is a box-shaped distribution diagram of the average particle size of shale samples from the 7th member of the Yanchang Formation in the Ordos Basin provided by an embodiment of the present invention;

[0050] Figure 8 This is a scatter plot of standard deviation and average particle size of shale in the 7th member of the Yanchang Formation in the Ordos Basin provided by an embodiment of the present invention;

[0051] Figure 9 is a box plot of the elastic modulus of shale fine-grained sedimentary rock particles under a peak load of 100 mN provided by an embodiment of the present invention;

[0052] Figure 10 This is a particle box diagram of the hardness of shale fine-grained sedimentary rock under a peak load of 100 mN provided by an embodiment of the present invention;

[0053] Figure 11A Schematic diagram of the average elastic modulus of shale fine-grained sediment particles provided by an embodiment of the present invention;

[0054] Figure 11B This is a histogram of the hardness of shale fine-grained sediment particles provided by an embodiment of the present invention;

[0055] Figure 12A This is a schematic diagram of granularity + angular division provided by an embodiment of the present invention;

[0056] Figure 12B This is a schematic diagram of the flatness + angularity division provided by an embodiment of the present invention;

[0057] Figure 12C This is a schematic diagram of the classification of flatness + angularity + elastic modulus + hardness provided by an embodiment of the present invention;

[0058] Figure 12D Schematic diagram of elastic modulus + hardness classification provided by an embodiment of the present invention;

[0059] Figure 12E This is a schematic diagram of the angularity + elastic modulus + hardness classification provided by an embodiment of the present invention;

[0060] Figure 12F This is a schematic diagram of the particle size + angularity + elastic modulus classification provided by an embodiment of the present invention;

[0061] Figure 13A This is a graph showing the intersection of particle size + angularity and TOC content provided by an embodiment of the present invention;

[0062] Figure 13B This is an intersection diagram of flatness + angularity and feldspar content provided by an embodiment of the present invention;

[0063] Figure 13C This is an intersection diagram of flatness + angularity and clay mineral content provided by an embodiment of the present invention;

[0064] Figure 13D This is an intersection diagram of flatness + angularity + elastic modulus + hardness type and clay mineral + TOC content provided by an embodiment of the present invention;

[0065] Figure 13E is an intersection diagram of elastic modulus + hardness type and pyrite content provided by an embodiment of the present invention;

[0066] Figure 13F This is a graph showing the intersection of angularity, elastic modulus, hardness and quartz content provided by an embodiment of the present invention;

[0067] Figure 13G This is an intersection diagram of the particle size + angularity + elastic modulus type and the calcite + dolomite + feldspar content provided by an embodiment of the present invention; DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0069] In order to solve the problems existing in the prior art, the present invention provides a method, system, medium, equipment and terminal for classifying fine-grained sediment particles. The present invention is described in detail below with reference to the accompanying drawings.

[0070] like Figure 1 As shown, the classification method of fine-grained sediment particles provided by the embodiment of the present invention includes the following steps:

[0071] S101, based on multi-scale and multi-view scanning electron microscopy identification technology, combined with ImageJ software to determine the microscopic morphological characteristics (particle size and shape characteristics) of fine-grained sediment particles;

[0072] S102, determine the micromechanical properties of fine-grained sediment particles using nanoindentation experiments;

[0073] S103, Quantitative characterization of the microstructural characteristics of fine-grained sedimentary particles: A five-unit characterization method is constructed using particle size, flatness, angularity, elastic modulus, and hardness to determine the characteristics of fine-grained sedimentary particles; based on the principle of the basic properties of the five-unit particles, the combination types of fine-grained sedimentary particles are divided according to the normalized parameters of the five-unit fine-grained sedimentary particles.

[0074] The quantitative characterization of the microstructural characteristics of the fine-grained deposited particles in step S101 provided in the embodiment of the present invention includes:

[0075] The microstructural characteristics of fine-grained sedimentary rocks were statistically analyzed with the help of multi-scale and multi-viewing field micropore identification technology. A field emission environmental scanning electron microscope was used to continuously move the end to end to take photos of the shale microstructure. The scanning electron microscope photos were stitched together to obtain an image reflecting the overall microscopic characteristics of the sedimentary rocks. The identified images were grayscale processed using ImageJ software to determine the multi-scale micropore structural characteristics.

[0076] The identified image is imported into ImageJ image processing software to obtain a digital image in black and white tones. The microstructural characteristic parameters of the particles are characterized by ImageJ software, including:

[0077] (1) Grayscale conversion: import the target image into the software and perform grayscale conversion on the image;

[0078] (2) Grayscale threshold setting: adjust the image threshold according to the grayscale value of the image so that the image shows the complete geometric shape of the particle size, keep the threshold concentrated in a stable range, and extract the particles according to the threshold;

[0079] (3) Automatic denoising: removing noise from the image after threshold processing by manually correcting the image or filtering and smoothing the image;

[0080] (4) Acquisition of geometric parameters: Calculate the geometric parameters of the particle objects, including the centroid coordinates (X, Y), axis length ratio, area, perimeter, equivalent ellipse perimeter, and convexity, and perform calibration counting;

[0081] (5) Export data: Export and transform data, save all data output in an Excel spreadsheet, and convert the measurement results to obtain the true geometric information of the particles.

[0082] The determination of the microscopic morphology and mechanical property characteristics of the fine-grained deposited particles in step S102 provided by the embodiment of the present invention includes:

[0083] The microscopic morphological characteristics of fine-grained sedimentary particles include particle size, flatness, and angularity, and the mechanical properties include elastic modulus, hardness, and creep.

[0084] Based on the multi-scale and multi-viewing field scanning electron microscopy identification technology and combined with ImageJ software, the particle size and particle size distribution of shale sample particles were statistically analyzed to determine the particle size distribution characteristics of shale sample particles.

[0085] The mathematical model is used to quantitatively characterize the morphological characteristic parameters of fine-grained sediment particles and determine the shape of fine-grained sediment particles. Among them, the particle flatness and perimeter angularity index of the sample are consistent with the logarithmic normal distribution H1:X~LN(μ,σ 2 ) and normal distribution H0:X~N(μ,σ 2 ) characteristics.

[0086] In step S103 provided by the embodiment of the present invention, based on the principle of the five basic properties of the particle, each parameter is dimensionlessly processed by normalization to achieve proportional scaling of the data, so that the data becomes a relative value relationship; wherein the normalization formula is:

[0087]

[0088] Where, X norm is the normalized data, X is the original data, X max and X min are the maximum and minimum values ​​of the original data respectively.

[0089] According to the normalized parameters of the five units of fine-grained sedimentary particles, the combination types of shale fine particles are divided into the following six categories: Type 1: particle size + angularity type; Type 2: flatness + angularity type; Type 3: flatness + angularity + elastic modulus + hardness type; Type 4: elastic modulus + hardness type; Type 5: angularity + elastic modulus + hardness type; Type 6: particle size + angularity + elastic modulus type.

[0090] The classification system for fine-grained sediment particles provided by an embodiment of the present invention includes:

[0091] Fine-grained sediment particle structure characterization module, which is used to construct a five-element characterization method using particle size, flatness, angularity, elastic modulus, and hardness to characterize fine-grained sediment particles;

[0092] The module for determining the micromorphology and mechanical properties of fine-grained sediment particles is used to determine the particle size and shape characteristics of fine-grained sediment particles based on multi-scale and multi-viewing field scanning electron microscopy identification technology combined with ImageJ software, and to determine the micromechanical properties of fine-grained sediment particles using nanoindentation experiments;

[0093] The fine-grained sediment particle type classification module is used to classify the combination types of fine-grained sediment particles based on the principle of the basic properties of the five units of particles and the normalized parameters of the five units of fine-grained sediment particles.

[0094] Example: Characteristic Analysis and Classification of Fine-Grained Sedimentary Particles in the 7th Member of the Yanchang Formation in Ordos

[0095] 1. Quantitative characterization of microstructural characteristics of fine-grained sediment particles

[0096] 1.1 Quantitative characterization technology of single particle geometric characteristics

[0097] (1) Stitching and identification of FE-SEM images

[0098] Fine-grained rocks are highly heterogeneous, and a single scanning electron microscope photograph cannot represent the true microstructural characteristics of the rock. Therefore, the microstructural characteristics of fine-grained sedimentary rocks are statistically analyzed with the help of multi-scale and multi-view micropore identification technology. The field emission environmental scanning electron microscope is used to continuously take photos of the shale microstructure, and the photos are stitched together in sequence. After identification and processing by software (ImageJ), the multi-scale micropore structural characteristics can be observed in all aspects (see Figure 2AThis new image analysis technology is more comprehensive and intuitive than local observation under a scanning electron microscope. After the multiple (8×8) shale microstructure images are spliced ​​together, it can avoid the randomness of the position selection of the traditional observation method to a certain extent, reduce the lack of global understanding of the shale pore structure and the errors caused by the selection of the sample observation position, and can present the multi-scale and multi-magnitude microstructure of fine-grained sedimentary rocks in one image, providing a new idea for the quantitative characterization and qualitative analysis of microstructure (see Figure 2B ).

[0099] The scanning electron microscope images taken at the beginning and end are stitched together to form a picture that can reflect the entire microscopic features of sedimentary rocks (see Figure 2C ), and based on this, the particles are identified. The yellow color in the figure is the identified particle shape (see Figure 2D ). Then, the recognized image was gray-scale processed using ImageJ software to obtain a digital image composed of black and white colors. The black area in the image represents the area of ​​the particles.

[0100] (2) Characterize the microstructural characteristic parameters of particles using ImageJ software

[0101] The identified image is imported into the image processing software to obtain a black and white digital image. The present invention uses the ImageJ image processing software developed by the National Institutes of Health. This software can easily obtain basic geometric parameters such as the number, perimeter, area, length and diameter of the particles, and can also segment, count and classify the target image. On this basis, the complex shape parameters such as particle size, flatness, Fourier shape index, perimeter angularity index, etc. are calculated in combination with Matlab mathematical analysis software. The specific process is shown in Figure 3 .

[0102] 1.2 Characterization of particle micromechanical properties

[0103] (1) Experimental instruments and principles

[0104] Nano-indenter can not only measure traditional hardness indexes, but also tensile indexes, impact indexes, etc. Nano-indenter is based on the indentation technology of depth-sensing indentation. It presses an indenter of known properties into the physical surface to be measured, continuously records the load-displacement loading and unloading curve, and then calculates indicators such as elastic modulus, hardness, yield stress, power law creep index, etc. As a high-precision indentation testing equipment, the load accuracy of nano-indenter has reached dozens of nano-Newtons and the displacement accuracy has reached 0.1nm. It is widely used in high-precision mechanical measurements of micron or nano-grain materials and films. Nano-indentation experiment is a microscopic mechanical experiment. Unlike conventional mechanical experiments, it has higher requirements for experimental measurement accuracy. It is usually required that the sample thickness should be no less than 10 times the indentation depth or 6 times the indentation radius. The sample size prepared by the present invention is 50*25*15mm, the parallelism of the upper and lower surfaces of the sample is no more than 0.5 degrees, and the verticality of the side surface to the experimental surface is no more than 0.5 degrees. Before conducting experimental tests, the samples were polished and the deformed layer was removed. The present invention uses sub-ion polishing technology to avoid the problem of temperature changes causing volatilization of organic matter in the rock sample to generate secondary pores, or thermal stress causing deformation of primary pores to generate artificial cracks.

[0105] A nanoindenter consists of three components: an indenter fixed to a rigid loading frame, a powered brake, and a displaceable sensor. Nanoindenters employ three primary loading methods: electromagnetic, electrostatic, and piezoelectric. They operate in two modes: normal and continuous. In normal mode, a single loading and unloading cycle can only measure a single hardness and elastic modulus value corresponding to the maximum load or maximum indentation depth. Cyclic mode, on the other hand, continuously measures contact stiffness during loading, yielding curves showing how hardness and elastic modulus vary with indentation depth.

[0106] Nanoindentation experiments primarily consist of three phases: loading, holding, and unloading. First, the indenter is placed on the rock sample surface and pressed into the sample at a specified maximum load and loading rate. Once the maximum load is reached, the pressure is held for a specified time to eliminate measurement errors. Then, the pressure is unloaded to zero at a specified unloading rate within a specified time. Finally, the indenter is lifted from the rock sample surface and moved to the next test point. Due to differences in test scale and precision, the experimental measurement steps vary slightly.

[0107] According to GB / T22458 standard and Hystrion manual, the specific experimental steps are as follows:

[0108] a. Sample installation. To reduce instrument flexibility, the sample should be firmly placed on a rigid support or in a fixture. The sample and the support or fixture should be rigidly connected, and the sample surface should be perpendicular to the indentation load.

[0109] b. Select the test location. The test results may be affected by the interface, free surface or other indentations, depending on the indenter shape and specimen properties.

[0110] c. Determine the contact zero point. For each test, the contact zero point should be specified.

[0111] d. Specify the test cycle. To avoid changes in the mechanical properties of the specimen surface due to collision, the indenter's approach speed to the specimen surface should be low and should not exceed 2 μm / s. A more reasonable speed is 10-20 nm / s, or even less. Consider drive properties, such as the indentation load, displacement rate, or strain rate control method, and the form and value of their parameters. The effective experimental time, such as the loading time, unloading time, and holding time at maximum load, are all 15 seconds, and the holding time for measuring the thermal drift rate after 90% unloading is 60 seconds. The data acquisition rate and thermal drift rate settings must also be considered.

[0112] e. Perform the test cycle. Perform the test cycle according to the manufacturer's or test method's requirements and record the load-displacement-time data.

[0113] f. Correction data. The acquired data should be corrected for contact zero, thermal drift, and instrument compliance.

[0114] The experimental process of the nanoindentation tester MFT-4000 is as follows:

[0115] a. Loosen the beam positioning knob, turn the beam 45 degrees clockwise, fix the sample on the fixture, reset the beam and tighten the beam positioning knob.

[0116] b. After the sample is placed, fix the press-in depth sensor bracket to the side of the host, adjust its position, screw the displacement test screw into the screw hole of the weight tray, and align the displacement sensor contact with the center of the screw.

[0117] c. Adjust the position of the displacement contact so that the contact position bar on the screen is displayed in the green segment, which means that the displacement sensor is adjusted into place.

[0118] d. Press the compensation curve to get the compensation parameters (the more times you perform this operation, the higher the measurement accuracy will be, generally more than five times is best).

[0119] e. Enter the sample number, material name, experimental parameters, and adjust the sample position.

[0120] f. Adjust the loading force to zero and adjust the position of the displacement probe.

[0121] g. Click the "Compensation Curve" button to compensate for the elastic deformation of the test bench.

[0122] h. Set the maximum load and load at a constant loading rate; maintain the load at the maximum load for 15 seconds, and then unload the load to zero at the same rate.

[0123] In nanoindentation measurement, hardness (H) and elastic modulus (E) are among the most representative mechanical parameters. Nanoindentation mechanical property characterization is based on the Oliver-Pharr method, proposed in 1992. Based on classical elastic contact mechanics, the elastic modulus is derived from the slope of the load-displacement curve, and the hardness is calculated based on the maximum applied load and the residual deformation area of ​​the indentation. This method is currently the most widely used for calculating the hardness and elastic modulus of nanoscale materials.

[0124] (2) Experimental plan

[0125] XRD analysis shows that shale is primarily composed of detrital minerals (quartz and feldspar), carbonates (calcite, dolomite, and pyrite), clay minerals, and organic matter. Therefore, this study focused on testing the micromechanical parameters of quartz, feldspar, calcite, dolomite, clay minerals, and organic mineral particles, including hardness and elastic modulus, and analyzed the relationships between these mechanical parameters.

[0126] 1.3 Single Particle Characterization Method - "Five-Unit Properties"

[0127] The microstructural characteristics of fine-grained sedimentary particles are fundamental, intrinsic properties that influence their physicochemical behavior under dynamic and static stresses, exerting a significant influence on porosity, permeability, chemical properties, microstructural characteristics, and stress-strain dynamics. The formation of fine-grained sedimentary particle fabric undergoes complex macroscopic and microscopic environmental conditions, from erosion of the original material to sedimentation and burial, with the ultimate result being reflected in the microscopic morphology of the sedimentary particles. Therefore, the microscopic morphology of sedimentary particles, to a certain extent, reflects the environment during the period of sedimentation and diagenesis, serving as "direct evidence" for geological change.

[0128] By integrating the morphology of fine-grained sedimentary particles and rock mechanics characteristics, and starting from the perspectives of particle force and deformation displacement, as well as particle geometric parameters, a "five-unit" characterization method is constructed to describe the characteristics of fine-grained sedimentary particles. The "five-unit" characteristics of particles are particle size, flatness, angularity, elastic modulus and hardness.

[0129] (1) Particle size

[0130] Particle size and particle size are two terms that characterize the size of particles. Particle size is based on a single particle, while particle size is based on a group of particles. Fine-grained sediment particles are irregular in shape and vary in size. Therefore, the concept of "calculated diameter" is used to characterize the diameter of irregular fine-grained sediment particles. By measuring the properties related to the particle size, the relevant parameters of the linear stiffness are derived to indirectly characterize the size of the particles. Previous studies have divided "calculated diameter" into four categories: axial diameter, spherical equivalent diameter, circular equivalent diameter and statistical diameter. The analysis of the particle appearance morphology this time is carried out on a two-dimensional scale, and most of the particles are irregular in shape, so the circular area equivalent diameter D is used. S As the diameter of the particles (see Figure 4 ).

[0131] The equivalent diameter of a circle is the diameter of a circle with the same area as the circle. The calculation formula is as follows:

[0132]

[0133] (2) Flatness of particles

[0134] For irregular particles, the shape of the particles can be expressed by the flatness ratio (flatness) (see Figure 5 ):

[0135] F=b / t (3)

[0136] Where F is the flatness ratio, t is the particle thickness, which is the distance between the parallel faces of the particle, and b is the particle width, which is the shortest distance between the other parallel faces and the planes intersecting them perpendicularly. The flatness ratio of fine-grained sediment particles is typically greater than 1, with larger values ​​indicating a more flaky particle.

[0137] (3) Angularity of particles

[0138] Since fine-grained sedimentary particles are embedded in the rock matrix, it is difficult to extract and separate them individually, making their three-dimensional overall observation difficult. Therefore, the present invention uses a two-dimensional parameter perimeter angularity index to finely characterize the angularity of fine-grained sedimentary particles.

[0139] In 2000, Mora and Kwan applied convexity to calculate the angularity of a shape as follows:

[0140]

[0141] (4) Elastic modulus

[0142] The elastic modulus parameters of fine-grained deposited particles can be calculated based on the measurement results of the nanoindentation experiment using the following formula. The traditional Oliver-Pharr method assumes that a tangent line is drawn through the maximum loading point of the nanoindentation curve, and the slope of the tangent line is the unloading stiffness S at the initial point. The calculation formula is as follows:

[0143]

[0144] Where A is the projected contact area of ​​the indentation, E* is the equivalent elastic modulus, which is related to the elastic moduli of the sample and the indenter, and β is a constant related to the shape of the indenter. The elastic modulus E of the rock being tested can be calculated using the following formula:

[0145]

[0146] Where E and v are the elastic modulus and Poisson's ratio of the sample, respectively. i and v i The elastic modulus and Poisson's ratio of the indenter are 1141 GPa and 0.07 respectively.

[0147] (5) Hardness

[0148] Nanoindenter can not only measure the Young's modulus of the sample, but also the hardness of the sample. The hardness of the sample can be expressed as:

[0149] H=P max / A (10)

[0150] Where, P max is the maximum load, A is the projected contact area of ​​the indentation, which is a function of the indentation contact depth and is related to the shape of the indenter. It is generally believed that the contact area of ​​the Berkovich indenter is:

[0151]

[0152] Where h c is the indentation contact depth. When calculating, A needs to be corrected. The specific formula is as follows:

[0153]

[0154] In the formula, C1 is 24.56, C1~C n It can be obtained by fitting, the indentation h c It can be calculated by the following formula:

[0155]

[0156] Where ε is related to the shape of the indenter.

[0157] 2. Micromorphology and mechanical properties of fine-grained sediment particles

[0158] The grain size and distribution characteristics of fine-grained sedimentary rocks are influenced by numerous factors, including provenance distance, parent rock composition, transportation method, transport distance, and hydrodynamic conditions. To investigate the influence of sedimentary environment on fine-grained particle size distribution, we investigated the coupled relationship between sedimentary facies type (semi-deep to deep lacustrine, shallow lacustrine, and deltaic) and fine-grained rock grain size. Experimental results show that fine-grained rocks within deep to semi-deep lacustrine facies have uniform grain sizes, with most particles smaller than 4 μm and primarily distributed in the 2 μm to 3.5 μm range. Deep to semi-deep lacustrine facies exhibit waves and lake currents, and their hydrodynamic conditions are somewhat similar to those of the ocean. However, the lakes are smaller in area and depth, resulting in weaker wave breaking and the absence of tidal forces. The quiet, low-energy water environment results in uniform sediment distribution and smaller grain sizes. Fine-grained rocks within shallow lacustrine facies have relatively uniform grain sizes, with average grain sizes slightly larger than those in deep to deep lacustrine facies, primarily ranging from 3.0 μm to 5.0 μm. Compared with the deep lake to semi-deep lake phase, the fine-grained sediments in the shallow lake phase are located in shallower water and have a more active sedimentary environment than the deep lake phase, so the grain size is larger. The grain size of fine-grained rocks developed in the delta phase varies greatly, covering a range of 0.24μm to 38.12μm, with strong heterogeneity, and the grain size ranges from 5.8μm to 8.0μm (see Figure 7 The results demonstrate that the environment during the deposition of fine-grained sediments has a certain control over particle size. However, compared with conventional reservoirs, the influence of the sedimentary environment on particle size is much weaker, and the range of particle size variation is very small. Fine-grained sedimentary rocks are generally deposited in deep, low-energy environments with weak hydrodynamic conditions, deep water bodies, and a lack of peripheral supply, resulting in relatively stable distribution over a large surface area. This results in less distinct phase markers such as grain size and less variability.

[0159] For many years, sedimentary rock researchers have attempted to use grain size data to determine the depositional environment. The present invention statistically calculates the average grain size and standard deviation of different sedimentary phases and finds that the scatter plot of the two can better distinguish the depositional environment. Figure 8 This is a scatter plot of standard deviation and mean grain size for the shale in the Yanchang Formation Member 7 of the Ordos Basin. The scatter plot of standard deviation and mean grain size is divided into three regions, with overlapping areas between the deep-semi-deep lacustrine facies and the shallow lacustrine facies.

[0160] Characterizing the mechanical properties of shale is one of the most challenging tasks in unconventional reservoirs. The mechanical properties of shale (elasticity and strength) affect many aspects of drilling, seismic exploration, and production. However, due to the complex composition and strong structural heterogeneity of shale, its mechanical properties are difficult to predict. Many factors affect the mechanical properties of shale, including external forces and the occurrence environment, as well as internal factors such as the material composition and structural characteristics of the rock itself. In addition, the presence of factors such as the shape of fine-grained sedimentary particles, the stacking state, pore distribution, bedding structure, and microfractures in shale makes the micromechanical properties of shale complex and diverse.

[0161] Figures 9 and 10The elastic modulus and strength box plots of different fine-grained sedimentary particles under the same peak load show that the elastic modulus of organic matter is distributed between 2.92GPa and 5.31GPa, the elastic modulus of pyrite varies between 272GPa and 285GPa, the elastic modulus of quartz is in the range of 72GPa to 88GPa, the elastic modulus of feldspar is in the range of 64GPa to 91GPa, and the elastic modulus of calcite is in the range of 51GPa to 57GPa.

[0162] A large amount of experimental test data shows that the microscopic rock mechanical properties of shale are closely related to the type of mineral particles. The elastic modulus of pyrite particles is the largest, followed by brittle minerals such as quartz, feldspar, calcite and dolomite, while the elastic modulus of clay minerals and organic matter is the smallest. The elastic modulus of quartz particles is distributed between 22.84GPa and 125.43GPa, with an average of 69.62GPa; the elastic modulus of feldspar particles is distributed between 42.00GPa and 102.11GPa, with an average of 67.82GPa; the elastic modulus of clay minerals is distributed between 7.30GPa and 99.34GPa, with an average of 50.38GPa; the elastic modulus of calcite particles is distributed between 11.17GPa and 11. The elastic modulus of dolomite particles ranges from 25.13 GPa to 77.57 GPa, with an average of 49.76 GPa; the elastic modulus of pyrite particles ranges from 253.90 GPa to 293.20 GPa, with an average of 273.90 GPa; the elastic modulus of organic matter ranges from 0.40 GPa to 4.70 GPa, with an average of 9.20 GPa (see Figure 11A ).

[0163] The distribution pattern of hardness values ​​of fine-grained sedimentary particles is similar to that of elastic modulus. Pyrite particles have the highest hardness, followed by brittle minerals such as quartz, feldspar, calcite and dolomite, while clay minerals and organic matter have the lowest hardness. The hardness of quartz particles ranges from 3.10 GPa to 38.80 GPa, with an average value of 12.10 GPa; the hardness of feldspar particles ranges from 1.50 GPa to 12.52 GPa, with an average value of 6.18 GPa; the hardness of clay minerals ranges from 1.37 GPa to 11.17 GPa, with an average value of 4.85 GPa; the hardness of calcite particles ranges from 1.44 GPa to 7.09 GPa, with an average value of 4.03 GPa; the hardness of dolomite particles ranges from 0.82 GPa to 12.93 GPa, with an average value of 4.32 GPa; the hardness of pyrite particles ranges from 30.12 GPa to 39.80 GPa, with an average value of 34.79 GPa; and the hardness of organic matter ranges from 0.20 GPa to 1.10 GPa, with an average value of 0.53 GPa (see Figure 11). The results show that the hardness of mineral particles is highly heterogeneous, and the hardness values ​​of brittle minerals are relatively close with little difference.

[0164] 3. Classification of fine-grained sedimentary particle types

[0165] 3.1 Basic types of single particles

[0166] The classification of fine-grained sediment particles is based on the principle of the "five units" basic properties of particles. However, the units and distribution ranges of the five parameters vary. Therefore, the principle of normalization is used to perform dimensionless processing on each parameter to achieve proportional scaling of the data, resulting in the data becoming a relative value relationship. The formula is as follows:

[0167]

[0168] Where, X norm is the normalized data, X is the original data, X max and X min are the maximum and minimum values ​​of the original data respectively.

[0169] According to the normalized parameters of the five units of fine-grained sedimentary particles, the types of fine-grained particles in the 7th member of the Yanchang Formation in the southern margin of Ordos can be divided into six categories (see Figures 12A to 12F ).

[0170] Type 1: Particle size + angularity. This type of particles has significant particle size and angularity characteristics.

[0171] Type #2: Flatness + angularity;

[0172] Type #3: Flatness + angularity + elastic modulus + hardness;

[0173] Type 4: elastic modulus + hardness type;

[0174] Type #5: angularity + elastic modulus + hardness type;

[0175] Type #6: Particle size + angularity + elastic modulus type.

[0176] 3.2 Relationship between particle type and mineral composition

[0177] In order to further explore the relationship between single particle type and mineral composition, the present invention calculated the fitting relationship between particle type and main minerals, and the specific values ​​are shown in Table 7. The results show that type 1 particles have a positive correlation with the TOC content in fine-grained sedimentary rocks (R 2 =0.644); Type II particles are correlated with the content of feldspar and clay minerals in fine-grained sedimentary rocks (R 2 =0.656; R 2 =0.509); the content of type III particles increases with the increase of the total content of TOC and clay minerals in fine-grained sedimentary rocks (R 2 =0.872); the higher the content of type IV particles, the higher the content of pyrite in fine-grained sedimentary rocks (R 2 =0.659); Type V particles show a positive correlation with the quartz content in fine-grained sedimentary rocks (R 2 =0.871); Type VI particles show a positive correlation with the sum of calcite, dolomite, and feldspar in fine-grained sedimentary rocks (R 2 =0.453). The particle type reflects the comprehensive characteristics of mineral particles and can represent one or more mineral particles. Therefore, the present invention believes that type 1 particles can represent the characteristics of organic matter in fine-grained rocks, type 2 particles can represent the characteristics of feldspar and clay minerals, type 3 particles can represent the characteristics of organic matter and clay minerals, type 4 particles reflect the characteristics of pyrite particles, type 5 particles reflect the characteristics of quartz, and type 6 particles reflect the characteristics of calcite, dolomite, and feldspar. Figures 13A to 13G shown.

[0178] Table 1 Relationship between particle type and mineral composition

[0179]

[0180] It should be noted that the embodiments of the present invention can be implemented by hardware, software, or a combination of software and hardware. The hardware portion can be implemented using dedicated logic; the software portion can be stored in a memory and executed by an appropriate instruction execution system, such as a microprocessor or dedicated design hardware. Those skilled in the art will appreciate that the above-mentioned devices and methods can be implemented using computer-executable instructions and / or contained in processor control code, for example, such as a carrier medium such as a disk, CD or DVD-ROM, a programmable memory such as a read-only memory (firmware), or a data carrier such as an optical or electronic signal carrier. The devices and modules of the present invention can be implemented by hardware circuits such as very large-scale integrated circuits or gate arrays, semiconductors such as logic chips, transistors, or programmable hardware devices such as field programmable gate arrays, programmable logic devices, etc., can also be implemented by software executed by various types of processors, or can be implemented by a combination of the above-mentioned hardware circuits and software, such as firmware.

[0181] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with this technical field within the technical scope disclosed by the present invention and within the spirit and principles of the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for classifying fine-grained sediment particles, characterized in that: include: Based on the multi-scale and multi-view scanning electron microscopy identification technology, the microstructural images of fine-grained sedimentary rocks were spliced ​​and identified by FE-SEM. The identified images were then grayscale processed using ImageJ software to determine the microstructural characteristic parameters of fine-grained sedimentary particles. Nanoindentation experiments were used to measure the micromechanical properties of fine-grained sediment particles, including hardness and elastic modulus. A five-element characterization method was constructed based on the combined morphology of fine-grained sediment particles and rock mechanical characteristics, based on particle force and deformation displacement, particle geometry, and particle size, flatness, angularity, elastic modulus, and hardness. This method was used to characterize fine-grained sediment particles. Based on the principle of the five basic properties of fine-grained sedimentary particles, the combination types of fine-grained sedimentary particles are divided; The classification method of fine-grained sediment particles specifically includes the following steps: Step 1: Based on the multi-scale and multi-view scanning electron microscopy identification technology, combined with ImageJ software, the microscopic morphology characteristics of fine-grained sediment particles are determined; Step 2: using nanoindentation experiments to determine the micromechanical properties of fine-grained sediment particles; Step three, quantitative characterization of the microstructural characteristics of fine-grained sedimentary particles: a five-unit characterization method is constructed using the particle size, flatness, angularity, elastic modulus and hardness of the particles to determine the characteristics of the fine-grained sedimentary particles; based on the principle of the basic properties of the five units of particles, the combination types of fine-grained sedimentary particles are divided according to the normalized parameters of the five units of fine-grained sedimentary particles.

2. The method for classifying fine-grained sediment particles according to claim 1, wherein: The quantitative characterization of the microstructural characteristics of fine-grained sediment particles in step 1 includes: The microstructural characteristics of fine-grained sedimentary rocks were statistically analyzed with the help of multi-scale and multi-viewing field micropore identification technology. A field emission environmental scanning electron microscope was used to continuously move the end to end to take photos of the shale microstructure. The scanning electron microscope photos were stitched together to obtain an image reflecting the overall microscopic characteristics of the sedimentary rocks. The identified images were grayscale processed using ImageJ software to determine the multi-scale micropore structural characteristics.

3. The method for classifying fine-grained sediment particles according to claim 1, wherein: In step 1, the identified image is imported into ImageJ image processing software to obtain a digital image in black and white tones. The microstructural characteristic parameters of the particles are characterized by ImageJ software, including: (1) Grayscale conversion: import the target image into the software and perform grayscale conversion on the image; (2) Grayscale threshold setting: adjust the image threshold according to the grayscale value of the image so that the image shows the complete geometric shape of the particle size, keep the threshold concentrated in a stable range, and extract the particles according to the threshold; (3) Automatic denoising: removing noise from the image after threshold processing by manually correcting the image or filtering and smoothing the image; (4) Acquisition of geometric parameters: Calculate the geometric parameters of the particle objects, including the centroid coordinates (X, Y), axis length ratio, area, perimeter, equivalent ellipse perimeter, and convexity, and perform calibration counting; (5) Export data: Export and transform data, save all data output in an Excel spreadsheet, and convert the measurement results to obtain the true geometric information of the particles.

4. The method for classifying fine-grained sediment particles according to claim 1, wherein: In step 2, the microscopic morphological characteristics of the fine-grained sediment particles include particle size, flatness, angularity, elastic modulus and hardness, and the mechanical property characteristics include elastic modulus, hardness and creep; Based on the multi-scale and multi-view scanning electron microscopy identification technology, combined with ImageJ software, the particle size and particle size distribution of shale sample particles were statistically analyzed to determine the particle size distribution characteristics of shale sample particles; The mathematical model is used to quantitatively characterize the morphological characteristic parameters of fine-grained sediment particles and determine the shape of fine-grained sediment particles; among them, the particle flatness and perimeter angularity index of the sample are respectively in accordance with the logarithmic normal distribution. H 1 :X~LN( μ , σ 2 ) and normal distribution H 0 :X~N( μ , σ 2 ) characteristics.

5. The method for classifying fine-grained sediment particles according to claim 1, wherein: In step 3, according to the principle of the basic properties of the five units of particles, each parameter is dimensionlessly processed by normalization to achieve proportional scaling of the data, so that the data becomes a relative value relationship; Among them, the normalization formula is: ; Where, X norm For normalized data, X is the original data, X max and X min are the maximum and minimum values ​​of the original data respectively; According to the normalized parameters of the five units of fine-grained sedimentary particles, the combination types of shale fine particles are divided into the following six categories: Type 1: particle size + angularity type; Type 2: flatness + angularity type; Type 3: flatness + angularity + elastic modulus + hardness type; Type 4: elastic modulus + hardness type; Type 5: angularity + elastic modulus + hardness type; Type 6: particle size + angularity + elastic modulus type.

6. A system for classifying fine-grained sediment particles using the method for classifying fine-grained sediment particles according to any one of claims 1 to 5, characterized in that: Classification systems for fine-grained sedimentary particles include: Fine-grained sediment particle structure characterization module, which is used to construct a five-element characterization method using particle size, flatness, angularity, elastic modulus, and hardness to characterize fine-grained sediment particles; The module for determining the micromorphology and mechanical properties of fine-grained sediment particles is used to determine the particle size and shape characteristics of fine-grained sediment particles based on multi-scale and multi-viewing field scanning electron microscopy identification technology combined with ImageJ software, and to determine the micromechanical properties of fine-grained sediment particles using nanoindentation experiments; The fine-grained sediment particle type classification module is used to classify the combination types of fine-grained sediment particles based on the principle of the basic properties of the five units of particles and the normalized parameters of the five units of fine-grained sediment particles.

7. A computer device, characterized in that: The computer device includes a memory and a processor. The memory stores a computer program. When the computer program is executed by the processor, the processor executes the steps of the method for classifying fine-grained deposited particles according to any one of claims 1 to 5.

8. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method for classifying fine-grained deposited particles according to any one of claims 1 to 5.

9. An information data processing terminal, characterized in that: The information data processing terminal is used to implement the fine-grained sediment particle classification system according to claim 6.

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