A static mechanical parameter characteristic digital rock simulation and characterization method

Abstract

The application discloses a static mechanical parameter characteristic digital rock simulation and characterization method, and the simulation and characterization method comprises the following steps: acquiring a digital image containing geological information; constructing a real geological feature digital rock according to the digital image; constructing a plurality of digital rocks with different layering angles; and performing a simulation test on the mechanical properties of the rocks with different layering angles. The application discloses the variation law of the static mechanical parameters of shale oil with the layering angle, and provides a new and unified prediction and evaluation method for the mechanical properties of shale oil in different regions.

Description

Technical Field

[0001] This invention relates to the field of rock mechanics analysis in oil and gas exploration, and in particular to a digital rock simulation and characterization method for static mechanical parameter characteristics. Background Technology

[0002] Shale oil refers to petroleum hosted in organic-rich shale formations. This type of oil and gas resource is characterized by the complexity and unconventionality of its occurrence environment. In China, the potential of continental shale oil resources is enormous, and the growth potential of its reserves and production is of great significance to the country's energy security and economic development. Due to the unique characteristics of shale oil reservoirs, their development and utilization face challenges different from those of traditional oil and gas fields. Laminar structures, as the smallest or thinnest distinguishable original sedimentary layers in sediments or sedimentary rocks, have a decisive influence on the characteristics of shale oil reservoirs. The laminar structure of shale not only determines the development of reservoirs and the migration and accumulation paths of oil, but also affects the distribution of so-called "sweet spots," i.e., areas with high oil and gas production potential. Furthermore, the laminar structure of shale is also the main cause of its anisotropy, which has a significant impact on the mechanical properties and engineering response characteristics of the rock. Given the low porosity and low permeability characteristics of shale, the efficient development of its reservoirs relies on advanced horizontal well drilling technology and large-scale hydraulic fracturing technology. Existing technologies can not only effectively increase the contact area of ​​oil and gas wells, but also improve the flowability of oil and gas from low-permeability rocks. However, the inherent anisotropy of shale presents unique challenges to engineering operations, such as wellbore stability and the propagation of hydraulic fractures. The mechanical response caused by this anisotropy must be fully considered when designing and implementing drilling and fracturing operations.

[0003] Currently, the rock mechanical parameters for studying the anisotropy of shale are mainly based on extensive laboratory experimental analysis. Hou Zhenkun conducted uniaxial compression tests on shale cored from different bedding directions, Heng Shuai conducted uniaxial and triaxial compression tests on shale with different bedding dip angles, triaxial compression tests on Tourenmire shale with different bedding angles, and uniaxial and triaxial compressive strength tests using Mancos shale. A series of uniaxial and Brazilian splitting tests were also conducted on gneiss, schist, and shale. Their experimental results show that shale exhibits significant anisotropy, with the elastic modulus being highest parallel to the bedding direction and lowest perpendicular to the bedding. The failure strength shows a "V"-shaped trend of first decreasing and then increasing with the bedding dip angle. Although experiments are an effective method for studying rock mechanical properties, they are often time-consuming, labor-intensive, costly, and destructive. Furthermore, the success rate of shale sample preparation is very low, and shale samples perpendicular to the bedding direction or at a certain angle to the bedding are difficult to obtain. More importantly, these methods have limitations in handling rock heterogeneity and complex structures, and cannot ensure the consistency of experimental samples. With the development of computer technology, digital rock analysis has become an effective tool for studying the mechanical properties of rocks. In the area of ​​using digital rock analysis to model the anisotropic static mechanical parameters of shale, two-dimensional numerical simulations were performed using bedding planes to characterize anisotropic rocks. A model of bonded grains with high-density smooth interconnections was used to simulate the anisotropic mechanical characteristics of schist under uniaxial compression. In summary, these numerical studies provide important insights into the characterization of rock mechanics and failure behavior; however, the model specimens constructed using these methods lack practical geological significance and differ significantly from actual rock masses, requiring further research.

[0004] Chinese Patent Application No. CN201510404832.4, entitled "A Method and Apparatus for Determining Shale Anisotropic Parameters," proposes to conduct acoustic anisotropic measurements on samples parallel to the shale bedding direction. By acquiring four wave velocities, corresponding elastic constants are obtained, and a fifth elastic constant is calculated. The anisotropic parameters of the shale are then derived through elastic constant conversion. While this invention offers the advantage of obtaining multiple elastic parameters in a single experiment, saving experimental time, it only measures the acoustic wave velocity of shale at horizontal dip angles. The resulting elastic parameters cannot fully characterize the static mechanical behavior of the rock.

[0005] Chinese patent application CN202010951018.5, entitled "A Method for Predicting Wellbore Collapse Instability in Hydrated Shale Formations," is based on Jaeger's anisotropic rock shear failure strength criterion. It introduces the equivalent hydration weakening stress of shale bedding shear strength and considers the shear failure strength at four lamellar-axial angles. This invention significantly improves the prediction of wellbore collapse instability in hydrated shale formations under shear failure conditions. However, this invention focuses on the shear failure of the formation rock, without broadly considering the anisotropic failure behavior of the rock, and without deeply considering the influence of lamellar dip angles. Summary of the Invention

[0006] In view of the above problems, the present invention is proposed to provide a method for digital rock simulation and characterization of static mechanical parameter characteristics that overcomes or at least partially solves the above problems.

[0007] According to one aspect of the present invention, a digital rock simulation and characterization method for static mechanical parameter characteristics is provided, the simulation and characterization method comprising:

[0008] Acquire digital images containing geological information;

[0009] Construct digital rock blocks with realistic geological features based on the digital images;

[0010] Constructing digital rocks with multiple dip angles of laminae;

[0011] Simulation experiments were conducted on the rock mechanics of multiple dip angles with lamellarity.

[0012] Optionally, acquiring digital images containing geological information specifically includes:

[0013] Image recognition is performed on the data source to obtain the texture data.

[0014] Optionally, constructing a digital rock block with realistic geological features based on the digital image specifically includes:

[0015] Digitize real geological features based on the digital images;

[0016] By assigning values ​​to multiple layered structural features, a digital rock block with realistic geological characteristics is constructed.

[0017] Optionally, the digitization of real geological features based on the digital image specifically includes:

[0018] Obtain digital images containing true information about the tilt ridges;

[0019] Based on image recognition technology, multiple mineral components are identified by gray-level histogram threshold segmentation, corresponding to multiple texture types;

[0020] The threshold segmentation results are processed into a grid, and multiple numbers are used to represent multiple mineral types to assemble a digital matrix containing real geological information.

[0021] Optionally, the step of assigning values ​​to multiple layered structural features to construct a digital rock block with realistic geological features specifically includes:

[0022] A homogeneous digital rock block is constructed based on the discrete element method. Through spatial geometric mapping, the geological information in the matrix is ​​assigned to the homogeneous digital rock block to obtain a digital rock block containing real laminar geological features.

[0023] In the particle flow discrete element method, the basic unit for constructing digital rock blocks is a series of rigid particles configured within a bound;

[0024] The interaction between particles is achieved through internal forces and torques at paired contact points;

[0025] In the granular flow model, the contact between particles is regarded as point contact, and a soft sphere contact model is used. The soft sphere contact model allows for overlapping areas between particles to simulate the deformation of real materials.

[0026] The calculation and updating of interparticle contact forces are based on a force-displacement contact model;

[0027] The force-displacement contact model typically includes elastic and damping components in the normal and tangential directions, as well as adhesive forces;

[0028] Simulate complex rock behavior, taking into account the heterogeneity and bedding structure of rocks.

[0029] Optionally, the step of assigning geological information from the matrix to homogeneous digital rock blocks to obtain digital rock blocks containing real laminar geological features specifically includes:

[0030] The laminar information in the digitized matrix is ​​converted into a digital grid containing coordinate information. Each grid node contains the corresponding laminar information, forming a digital grid containing real laminar geological information.

[0031] Iterate through each particle element in the homogeneous digital rock block constructed by the discrete element method;

[0032] Match the coordinates of the particle elements obtained in each search with the coordinates of the digital texture mesh nodes;

[0033] After successful coordinate matching, the geological information contained in the grid node is assigned to the corresponding particle element. After the traversal search is completed, a digital rock block containing a real layered structure is obtained.

[0034] Based on the information contained in the digital texture mesh nodes, each particle element is assigned corresponding physical properties, and each particle contact is identified through particle element contact and assigned corresponding contact mechanical properties.

[0035] Optionally, the construction of digital rocks with multiple bedding dip angles specifically includes:

[0036] Simulated isometric coring was performed on digital rock blocks containing real laminar geological features to obtain anisotropic digital rock samples with various laminar dip angle characteristics.

[0037] Optionally, the simulated isostatic coring operation on digital rock blocks containing real laminar geological features specifically includes:

[0038] Determine the center point of the sample;

[0039] Detailed statistics were collected and particle information of the located area was obtained. Based on the particle information, standard samples with various laminar dip angle geological information were reconstructed.

[0040] The reconstructed sample model is given a contact constitutive model to simulate the mechanical behavior of real rock materials.

[0041] Optionally, determining the center point of the centering process specifically includes:

[0042] Precisely locate the rock particles contained in samples taken at different core angles under standard sample size to obtain particle information contained in various digital rock blocks.

[0043] Optionally, the step of assigning a contact constitutive model to the reconstructed sample model to simulate the mechanical behavior of real rock materials specifically includes:

[0044] In the discrete element particle flow method, the interactions and motion behaviors between particles are calculated based on Newton's laws of motion and a given contact force-displacement model.

[0045] Optionally, the simulation test of rock mechanics for multiple dip-angled lamellar rocks specifically includes:

[0046] Numerical simulation experiments of rock mechanics with various lamellar dip angles were conducted on the digital rock after parameter correction;

[0047] In the application of the discrete element method, rigid walls are used to simulate loading devices in real experiments;

[0048] The confining pressure of the specimen was applied through the wall, simulating the pressure state that actual rock would experience in an underground environment.

[0049] This invention provides a method for simulating and characterizing static mechanical parameters of digital rocks. The method includes: acquiring digital images containing geological information; constructing digital rock blocks with realistic geological features based on the digital images; constructing digital rocks with multiple dip angles; and conducting simulation experiments on the mechanics of the dip-angled rocks. This reveals the variation law of static mechanical parameters of shale oil with dip angle, providing a new and unified method for predicting and evaluating the mechanical properties of shale oil from different regions.

[0050] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A flowchart illustrating a digital rock simulation and characterization method for static mechanical parameter characteristics provided in an embodiment of the present invention;

[0053] Figure 2 This is a schematic diagram of the reconstruction of an equivalent digital rock block model based on a real shale oil thin section, provided in an embodiment of the present invention.

[0054] Figure 3 A schematic diagram of a digital rock model with different lamellar dip angles provided in an embodiment of the present invention;

[0055] Figure 4 A schematic diagram showing the comparison between indoor experimental and numerical simulation results provided in an embodiment of the present invention;

[0056] Figure 5 A schematic diagram illustrating the relationship between different lamellar dip angles and (a): peak intensity of shale; (b): static Young's modulus; (c): static Poisson's ratio, provided for embodiments of the present invention.

[0057] Figure 6 This is a schematic diagram of the mechanical components of the linear parallel bonding model provided in an embodiment of the present invention. Detailed Implementation

[0058] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0059] The terms "comprising" and "having," and any variations thereof, in the specification, embodiments, claims, and drawings of this invention are intended to cover non-exclusive inclusion, such as including a series of steps or units.

[0060] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0061] Example 1

[0062] like Figure 1 As shown, a digital rock simulation and characterization method for static mechanical parameter characteristics includes:

[0063] Acquire digital images containing geological information;

[0064] Construct digital rock blocks with realistic geological features based on the digital images;

[0065] Constructing digital rocks with multiple dip angles of laminae;

[0066] Simulation experiments were conducted on the rock mechanics of multiple dip angles with lamellarity.

[0067] (1) Construction of digital rock blocks with real geological features

[0068] ① Digitization of Real Geological Features. Digital images containing accurate dip and laminar flow information are acquired through field observation and photography of outcrops, rock scanning, and other methods. Based on image recognition technology, different mineral components are identified using grayscale histogram thresholding, thus corresponding to different laminar flow types. The thresholding results are then processed into a grid for digitization, using different numbers to represent different mineral types, ultimately assembling a digital matrix containing accurate geological information.

[0069] ② Assignment of Different Laminar Structure Features. First, a homogeneous digital rock block is constructed based on the Discrete Element Method (DEM). Then, through spatial geometric mapping, the geological information in the matrix is ​​assigned to the homogeneous digital rock block. Specifically, the laminar information in the digitized matrix is ​​converted into a digital grid containing coordinate information. Each grid node contains corresponding laminar information, thus forming a digital grid containing real laminar geological information. Then, each particle element in the homogeneous digital rock block constructed by the DEM is traversed and searched. The coordinates of each particle element obtained in each search are matched with the coordinates of the digital laminar grid node. If a coordinate match is successful, the geological information contained in that grid node is assigned to the corresponding particle element. After the traversal and search are completed, a digital rock block containing real laminar structure is obtained. Then, based on the information contained in the digital laminar grid node, each particle element is assigned corresponding physical properties, and each particle contact is identified through particle element contact and assigned corresponding contact mechanical properties. For example, the number "1" represents a specific type of laminar structure; therefore, all particles marked "1" will be assigned the corresponding physical properties of that laminar structure type, and particle contacts will be assigned corresponding contact mechanical properties. Finally, a digital rock block containing real laminar geological features is obtained.

[0070] In the granular flow discrete element method, the basic unit for constructing digital rock blocks is a series of rigid particles configured within a boundary formed by rigid walls. The interactions between these particles are primarily achieved through internal forces and moments at paired contact points. In the granular flow model, particle contact is treated as point contact, employing a soft-sphere contact model. This model allows for some overlap between particles, thus simulating the deformation of real-world materials. The motion of each particle follows Newton's second law, meaning that the particle's acceleration is directly proportional to the net force acting on it and inversely proportional to its mass. The calculation and updating of contact forces between particles are based on a force-displacement contact model. In this model, the contact force depends not only on the relative position (displacement) between particles but also on their relative velocity. The force-displacement model typically includes elastic and damping components in the normal and tangential directions, as well as possible adhesive forces. This approach allows for the simulation of complex rock behavior, particularly when considering the heterogeneity and bedding structure of rocks.

[0071] (2) Constructing digital rocks with different dip angles of lamination

[0072] The digital rock block containing realistic lamellar geological features constructed in step (1) is subjected to simulated core sampling to obtain anisotropic digital rock samples with different lamellar dip angles. The equipotential core sampling method used in this process ensures that the different samples obtained have the same geological properties, thereby avoiding the influence of other heterogeneities within the rock on the simulation results. The equipotential core sampling implementation steps include:

[0073] ① Determine the center point of the core sample. Based on this, accurately locate the rock particles contained in samples taken at different core angles under the standard sample size to obtain particle information contained in different digital rock blocks.

[0074] ② Detailed statistical analysis and acquisition of particle information for the located area. Based on this information, standard samples with different dip angles of laminae are reconstructed, ensuring the authenticity and consistency of the geological characteristics of each sample.

[0075] ③ Assign an appropriate contact constitutive model to the reconstructed sample model to simulate the mechanical behavior of real rock materials. In the discrete element particle flow method, the interaction and motion behavior between particles are calculated based on Newton's laws of motion and a given contact force-displacement model.

[0076] The constitutive model for particle contact mechanics selected in this invention is the linear parallel bond model. This model is suitable for simulating the mechanical behavior of soil and rock materials, accurately capturing the contact and bonding characteristics between particles, such as friction, collision, and adhesion. Through simulation, we can gain a deeper understanding and predict the influence of different lamination dip angles on the mechanical properties of rocks, providing important theoretical basis and technical guidance for the design and construction of geotechnical engineering. Furthermore, this method has broad application prospects in fields such as petroleum engineering and mining engineering, and has significant practical implications for understanding and optimizing corresponding engineering operations.

[0077] In the granular flow method, each particle is treated as an independent entity, and its motion and interactions are governed by the following main equations:

[0078] Linear equations of motion:

[0079]

[0080] Where, m i It is the mass of the particles. It is the position vector of the particle. It is the resultant force acting on the particles.

[0081] Equations of angular motion:

[0082]

[0083] Among them, I i It is the moment of inertia of the particle. It is the rotation angle vector of the particle. It is the resultant torque acting on the particle.

[0084] The linear parallel bond contact model updates the contact force and torque using the following formula:

[0085]

[0086] Among them, F c It is a contact force, F l It is a linear contact force, F d It is damping force. It is a parallel adhesive contact force, M C It is the contact torque. This refers to the parallel bonding contact torque. A schematic diagram of the mechanical components of a linear parallel bonding model is shown below. Figure 6 As shown.

[0087] The force-displacement law for parallel adhesive force and moment consists of the following steps:

[0088] Updated bond cross-sectional properties:

[0089]

[0090] in It is the cross-sectional area. The moment of inertia of the cross section of the parallel key (about the direction along the line it passes through), and It is the polar moment of inertia of the parallel key section (around the line passing through and along the direction). The bonded cross section is {rectangular in two dimensions; circular in three dimensions}.

[0091] renew

[0092]

[0093] Where Δδ n It is the relative normal displacement increment

[0094] renew

[0095]

[0096] Where Δδ s It is the relative tangential displacement increment

[0097] renew

[0098]

[0099] Where Δθ t It is the relative twisting rotation increment

[0100] renew

[0101]

[0102] Where Δθ b It is the relative twisting rotation increment

[0103] Update the maximum normal stress and shear stress around the parallel bond perimeter:

[0104]

[0105] Enforcement of strength limits. If the tensile strength limit is exceeded, the bond will break under tension.

[0106]

[0107] If the bond does not fracture under tension, a shear strength limit is enforced. Shear strength is the average normal stress acting on the cross-section parallel to the bond. If the shear strength limit is exceeded, the bond fails in shear.

[0108]

[0109] By iteratively solving the above equations, the motion and interactions of initial particles can be simulated, thus reproducing in detail the dynamic behavior between particles and the macroscopic mechanical response of the rock. The accuracy of this process is crucial, as it directly affects the realism and reliability of the simulation results. To improve the model's accuracy, further incorporating indoor rock mechanics experimental results, digital rock mechanics simulations at different dip angles were conducted. These experimental results provided important benchmark data for verifying and correcting model parameters, ensuring that the model accurately reflects the mechanical behavior of real rocks. Correcting the model parameters allows the simulation results to better match the actual mechanical properties of rocks. This includes adjusting parameters such as the contact force model parameters between particles, the elastic modulus, and the coefficient of friction to ensure that the simulation environment truly reflects the physical and mechanical properties of the rock. After parameter correction, the parameters were assigned to digital rock models with different dip angles and laminations, and then static mechanical simulations of digital rock samples with the same geological characteristics but different dip angles were performed.

[0110] (3) Simulation test of rock mechanics of different dip angles in layered rocks

[0111] Numerical simulation experiments on rock mechanics with different bedding angles were conducted on digitally corrected rock samples to deeply analyze and understand the mechanical behavior and intrinsic failure mechanism of shale under varying stress conditions. In the application of the discrete element method (DEM), rigid walls were used to simulate the loading device in real experiments. This technique not only replicates the physical environment of laboratory tests but also precisely controls the loading conditions. The confining pressure of the samples was applied through these walls, simulating the pressure state experienced by actual rock in the underground environment. Through this simulation, the microscopic failure characteristics of shale with different bedding angles during the stress process were revealed, including crack initiation, propagation, and failure penetration. These observations not only provide an intuitive understanding of the mechanical behavior of shale but also help us explore the influence of bedding angle on shale failure and its intrinsic mechanism. Through mechanical simulation experiments with samples at different dip angles, the influence of bedding angle on shale strength, deformation characteristics, and failure modes was evaluated, leading to a more comprehensive analysis of the mechanical behavior of shale.

[0112] This invention is applicable to the development of shale oil and gas reservoirs, especially in the reservoir description and evaluation stage. By using digital rock simulation to study the mechanical characteristics of laminae at different dip angles, it provides geological engineers with accurate predictions of shale mechanical parameters and constitutive relationships, thereby guiding actual drilling and fracturing operations.

[0113] Example 2

[0114] Based on the invention, this embodiment effectively conducted digital rock mechanics numerical simulation experiments with different lamellar dip angles. The specific implementation steps are as follows:

[0115] (1) Data Acquisition and Image Recognition: First, image recognition was performed on the data source of the Niuye 1 well in the Jiyang Depression to accurately acquire the laminar data. This step is crucial because it provides the foundation for constructing digital rock blocks with realistic geological features.

[0116] (2) Digital Rock Block Construction: Using the discrete element method (DEM) particle flow approach and the acquired laminar flow data, a digital rock block containing realistic geological features was constructed. This digital rock block accurately reflects the geological structure of actual rocks, providing a solid foundation for subsequent digital rock mechanics simulations. Figure 2 The diagram shows a reconstruction of an equivalent digital rock block model based on a real shale oil thin section.

[0117] (3) Equivalent coring and sample preparation: Next, using an equivalent coring method at 15° intervals, seven digital rock samples with laminar dip angles of 0°, 15°, 30°, 45°, 60°, 75°, and 90° were successfully obtained. This coring method ensured the comparability between samples and reduced heterogeneity errors caused by differences in geological characteristics. Figure 3 The diagram shows a digital rock model with various lamellar dip angles.

[0118] (4) Rock Mechanics Simulation and Parameter Correction: Based on the results of indoor rock mechanics tests, a rock mechanics simulation was first performed on a 0° dip specimen. This process corrected the contact microstructure parameters of the model. This step is crucial because it ensures the accuracy and reliability of the model. For example... Figure 4 The diagram shows a comparison between the results of the indoor experiments and the numerical simulation.

[0119] (5) Simulation of mechanical properties of samples with different dip angles: Based on the invention (3), rock mechanics test simulations were carried out on digital rock samples with different dip angles of lamination. This process revealed the influence of the dip angle of lamination on the failure characteristics and mechanical properties of shale.

[0120] like Figure 5 As shown, the simulation results reveal the unique mechanical properties and failure modes of shale under different dip angles. This finding not only aligns with the patterns observed in laboratory rock mechanics experiments, but more importantly, provides new insights into the failure characteristics of shale with different dip angles at the microscopic level. Through these detailed numerical simulations, this invention can deepen the understanding of the mechanical behavior of shale under different geological conditions, thereby providing a scientific basis and technical strategies for the effective development and scientific management of shale reservoirs.

[0121] Beneficial effects: First, based on field outcrop observations and photographs, and rock scanning analysis, a digital matrix containing real geological information was assembled. Then, through spatial geometric mapping, digital rock blocks containing real geological features were constructed. Furthermore, by employing equipotential coring, digital cores with different dip angles and containing the same geological properties were obtained.

[0122] Second, numerical simulation experiments on rock mechanics with different bedding angles were conducted using digital rock simulation methods. The implementation of this innovative method not only provides in-depth insights into the influence of shale bedding angle on its mechanical properties, but also successfully clarifies the relationship between shale bedding angle and its mechanical properties, laying the foundation for guiding the dynamic and static characteristics of different formation dip angles during actual drilling and fracturing.

[0123] Third, this invention reveals the variation law of static mechanical parameters of shale oil with the dip angle of the laminae, providing a new and unified method for predicting and evaluating the mechanical properties of shale oil in different regions, and providing technical support for subsequent engineering drilling and fracturing of shale oil reservoirs.

[0124] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for digital rock simulation and characterization of static mechanical parameters, characterized in that, The simulation and characterization methods include: Acquire digital images containing geological information; Construct digital rock blocks with realistic geological features based on the digital images; Constructing digital rocks with multiple dip angles of laminae; Simulation experiments were conducted on the rock mechanics of multiple dip angles with lamellarity.

2. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 1, characterized in that, The acquisition of digital images containing geological information specifically includes: Image recognition is performed on the data source to obtain the texture data.

3. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 1, characterized in that, The specific steps of constructing digital rock blocks with realistic geological features based on the digital images include: Digitize real geological features based on the digital images; By assigning values ​​to multiple layered structural features, a digital rock block with realistic geological characteristics is constructed.

4. The method for digital rock simulation and characterization of static mechanical parameters according to claim 3, characterized in that, The digitization of real geological features based on the digital image specifically includes: Obtain digital images containing true information about the tilt ridges; Based on image recognition technology, multiple mineral components are identified by gray-level histogram threshold segmentation, corresponding to multiple texture types; The threshold segmentation results are processed into a grid, and multiple numbers are used to represent multiple mineral types to assemble a digital matrix containing real geological information.

5. The method for digital rock simulation and characterization of static mechanical parameters according to claim 3, characterized in that, The process of assigning values ​​to multiple layered structural features to construct a digital rock block with realistic geological characteristics specifically includes: A homogeneous digital rock block is constructed based on the discrete element method. Through spatial geometric mapping, the geological information in the matrix is ​​assigned to the homogeneous digital rock block to obtain a digital rock block containing real laminar geological features. In the particle flow discrete element method, the basic unit for constructing digital rock blocks is a series of rigid particles configured within a bound; The interaction between particles is achieved through internal forces and torques at paired contact points; In the granular flow model, the contact between particles is regarded as point contact, and a soft sphere contact model is used. The soft sphere contact model allows for overlapping areas between particles to simulate the deformation of real materials. The calculation and updating of interparticle contact forces are based on a force-displacement contact model; The force-displacement contact model typically includes elastic and damping components in the normal and tangential directions, as well as adhesive forces; Simulate complex rock behavior, taking into account the heterogeneity and bedding structure of rocks.

6. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 5, characterized in that, The process of assigning geological information from the matrix to homogeneous digital rock blocks to obtain digital rock blocks containing real layered geological features specifically includes: The laminar information in the digitized matrix is ​​converted into a digital grid containing coordinate information. Each grid node contains the corresponding laminar information, forming a digital grid containing real laminar geological information. Iterate through each particle element in the homogeneous digital rock block constructed by the discrete element method; Match the coordinates of the particle elements obtained in each search with the coordinates of the digital texture mesh nodes; After successful coordinate matching, the geological information contained in the grid node is assigned to the corresponding particle element. After the traversal search is completed, a digital rock block containing a real layered structure is obtained. Based on the information contained in the digital texture mesh nodes, each particle element is assigned corresponding physical properties, and each particle contact is identified through particle element contact and assigned corresponding contact mechanical properties.

7. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 1, characterized in that, The digital rock constructed with multiple lamellar dip angles specifically includes: Simulated isometric coring was performed on digital rock blocks containing real laminar geological features to obtain anisotropic digital rock samples with various laminar dip angle characteristics.

8. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 7, characterized in that, The simulated isostatic coring operation on digital rock blocks containing real laminar geological features specifically includes: Determine the center point of the sample; Detailed statistics were collected and particle information of the located area was obtained. Based on the particle information, standard samples with various laminar dip angle geological information were reconstructed. The reconstructed sample model is given a contact constitutive model to simulate the mechanical behavior of real rock materials.

9. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 8, characterized in that, The determination of the center point for the centering process specifically includes: Precisely locate the rock particles contained in samples taken at different core angles under standard sample size to obtain particle information contained in various digital rock blocks.

10. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 8, characterized in that, The specific steps of assigning a contact constitutive model to the reconstructed sample model to simulate the mechanical behavior of real rock materials include: In the discrete element particle flow method, the interactions and motion behaviors between particles are calculated based on Newton's laws of motion and a given contact force-displacement model.

11. The method for digital rock simulation and characterization of static mechanical parameter characteristics according to claim 1, characterized in that, The simulation test of rock mechanics for multiple dip-angled laminations specifically includes: Numerical simulation experiments of rock mechanics with various lamellar dip angles were conducted on the digital rock after parameter correction; In the application of the discrete element method, rigid walls are used to simulate loading devices in real experiments; The confining pressure of the specimen was applied through the wall, simulating the pressure state that actual rock would experience in an underground environment.

Images