Method and device for representing the relationship between dynamic and static elastic parameters of rock based on variable confining pressure

Abstract

The embodiment of the present application belongs to the technical field of rock mechanics, and discloses a rock dynamic and static elastic parameter relationship representation method and equipment based on variable confining pressure. The rock dynamic and static elastic parameter relationship representation method based on variable confining pressure comprises the following steps: determining the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; applying multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confinings; measuring the dynamic and static elastic parameters of the target rock in the process of applying multiple levels of deviatoric stress, and determining the relationship between the dynamic and static elastic parameters. The present application not only optimizes the selection of stress amplitude, but also effectively reduces the influence of rock sample heterogeneity on test results. In addition, through the sound force joint measurement experiment and the establishment of the dynamic and static elastic parameter relationship model, the present application can accurately correct the dynamic and static test model, and provide reliable data support for rock mechanics research and geological engineering practice.

Description

Technical Field

[0001] The embodiments of the present invention relate to the field of rock mechanics technology, and in particular to a method, apparatus, equipment, medium and product program for characterizing the relationship between dynamic and static elastic parameters of rocks based on variable confining pressure. Background Technology

[0002] In the early assessment stages of oil and gas reservoirs, predicting the static elastic modulus using dynamic elastic modulus can reduce reliance on expensive and time-consuming static tests, accelerating the exploration process. Furthermore, in designing underground engineering projects such as tunnels, mines, and oil and gas wells, accurately predicting the static elastic modulus of rocks helps optimize engineering designs and improve structural stability and safety.

[0003] Existing methods for determining the dynamic elastic modulus of rocks to predict their static elastic modulus have at least the following problems:

[0004] Rock heterogeneity: Rocks in nature often exhibit high heterogeneity, including differences in mineral composition, pore structure, and the degree of fracture development. This heterogeneity leads to significant variations in the dynamic and static elastic moduli of rocks among different samples, increasing the complexity of testing and prediction.

[0005] Selection of the amplitude of the deviatoric stress cycle: As mentioned earlier, an excessively large deviatoric stress cycle amplitude may lead to premature rock failure, while an excessively small amplitude may fail to adequately reflect the dynamic and static characteristics of the rock. How to minimize the excitation of its nonlinear behavior while ensuring the integrity of the rock is an important issue in test design. Summary of the Invention

[0006] The purpose of this invention is to provide at least one method and device for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure. The aim is to solve the problems of test instability caused by the heterogeneity of rock samples, difficulty in selecting deviatoric stress amplitude, and inaccuracy of dynamic and static test models. The invention aims to provide an efficient solution that can improve test stability, optimize stress amplitude selection, and accurately correct dynamic and static test models.

[0007] To address the aforementioned technical problems, at least one embodiment of the present invention provides a method for characterizing the relationship between dynamic and static elastic parameters of rock based on variable confining pressure, comprising:

[0008] The deviatoric stress loading amplitude is determined based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features;

[0009] Under multiple confining pressures, multiple levels of deviatoric stress are applied to the target rock according to the deviatoric stress loading amplitude;

[0010] The dynamic and static elastic parameters of the target rock are measured during the application of the multi-level deviatoric stress, and the relationship between the dynamic and static elastic parameters is determined.

[0011] In some embodiments, applying multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures includes:

[0012] Under each confining pressure, a series of deviatoric stress cycles are set according to the deviatoric stress loading amplitude to apply multiple levels of deviatoric stress to the target rock.

[0013] In some embodiments, a method for characterizing the dynamic and static elastic parameter relationship of rocks based on varying confining pressure further includes:

[0014] The amplitude, frequency, and duration of the deviatoric stress cycle are determined based on the rock type and the physical characteristics.

[0015] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0016] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0017] In some embodiments, measuring the static elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0018] During the multi-level deviatoric stress process, the target rock is subjected to triaxial compression testing to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0019] The static Poisson's ratio and the static Young's modulus are determined based on the axial stress, axial strain, and radial strain.

[0020] In some embodiments, measuring the dynamic elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0021] During the multi-level deviatoric stress process, the target rock is subjected to ultrasonic testing to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0022] The dynamic Poisson's ratio is determined based on the longitudinal wave velocity and the transverse wave velocity;

[0023] The dynamic Young's modulus is determined based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0024] In some embodiments, after measuring the dynamic and static elastic parameters of the target rock during the application of the multi-level deviatoric stress and determining the relationship between the dynamic and static elastic parameters, the method further includes:

[0025] Determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure;

[0026] The relationship between the dynamic elastic parameter and the static elastic parameter is corrected based on the ratio.

[0027] At least one embodiment of the present invention also provides a device for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure, comprising:

[0028] The deviatoric stress loading amplitude determination module is used to determine the deviatoric stress loading amplitude based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features;

[0029] A multi-level deviatoric stress application module is used to apply multi-level deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures.

[0030] The relationship determination module is used to measure the dynamic elastic parameters and static elastic parameters of the target rock during the application of the multi-level deviatoric stress, and to determine the relationship between the dynamic elastic parameters and the static elastic parameters.

[0031] In some embodiments, the multi-level deviatoric stress application module includes:

[0032] A multi-level deviatoric stress application unit is used to set a series of deviatoric stress cycles according to the deviatoric stress loading amplitude under each confining pressure in order to apply multi-level deviatoric stress to the target rock.

[0033] In some embodiments, a device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure further includes:

[0034] The deviatoric stress cycle parameter determination module is used to determine the amplitude, frequency, and duration of the deviatoric stress cycle process based on the rock type and the physical characteristics.

[0035] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0036] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0037] In some embodiments, the relationship determination module includes:

[0038] A stress-strain determination unit is used to perform triaxial compression tests on the target rock during the multi-level deviatoric stress process to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0039] The static elastic parameter determination unit is used to determine the static Poisson's ratio and the static Young's modulus based on the axial stress, axial strain, and radial strain.

[0040] In some embodiments, the relationship determination module further includes:

[0041] A velocity determination unit is used to perform ultrasonic testing on the target rock during the multi-level deviatoric stress process to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0042] A dynamic Poisson ratio determination unit is used to determine the dynamic Poisson ratio based on the longitudinal wave velocity and the transverse wave velocity;

[0043] The dynamic Young's modulus determination unit is used to determine the dynamic Young's modulus based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0044] In some embodiments, a device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure further includes:

[0045] The ratio determination module is used to determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure.

[0046] The relationship correction module is used to correct the relationship between the dynamic elastic parameter and the static elastic parameter based on the ratio.

[0047] At least one embodiment of the present invention also provides an electronic device, comprising: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the above-described method for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure.

[0048] At least one embodiment of the present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for characterizing the relationship between dynamic and static elastic parameters of rocks based on variable confining pressure.

[0049] The present invention provides a method and apparatus for characterizing the relationship between dynamic and static elastic parameters of rocks based on variable confining pressure. The method includes: first, determining the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; then, applying multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures; finally, measuring the dynamic and static elastic parameters of the target rock during the application of multiple levels of deviatoric stress, and determining the relationship between the dynamic and static elastic parameters.

[0050] The corresponding device for characterizing the relationship between dynamic and static elastic parameters of rocks based on varying confining pressure includes: a deviatoric stress loading amplitude determination module, used to determine the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters and structural features; a multi-level deviatoric stress application module, used to apply multi-level deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures; and a relationship determination module, used to measure the dynamic and static elastic parameters of the target rock during the application of multi-level deviatoric stress and determine the relationship between the dynamic and static elastic parameters.

[0051] This invention determines a reasonable deviatoric stress loading amplitude, designs a multi-stage deviatoric stress cyclic loading scheme, and conducts acoustic-mechanical measurements to simultaneously acquire the dynamic and static elastic parameters of the rock. A model is established based on experimental data and corrected using triaxial compression experimental data to improve prediction accuracy. This invention effectively improves the testing stability of the dynamic and static elastic parameters of rocks, providing accurate elastic modulus data for petroleum and geological engineering, and is of great significance for engineering design and construction safety. Attached Figure Description

[0052] One or more embodiments are illustrated by way of example with reference to the accompanying drawings, and these illustrative descriptions do not constitute a limitation on the embodiments.

[0053] Figure 1 This is a flowchart illustrating a method for characterizing the relationship between dynamic and static elastic parameters of rock based on variable confining pressure, provided by an embodiment of the present invention.

[0054] Figure 2 This is a flowchart illustrating step 300 provided in one embodiment of the present invention;

[0055] Figure 3 This is a flowchart illustrating another step 300 provided in one embodiment of the present invention;

[0056] Figure 4 This is a flowchart illustrating another method for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure, provided by an embodiment of the present invention.

[0057] Figure 5 This is a flowchart illustrating a method for characterizing the relationship between dynamic and static elastic parameters of rock based on variable confining pressure, provided by a specific embodiment of the present invention.

[0058] Figure 6 This is a technical roadmap of a method for characterizing the relationship between dynamic and static elastic parameters of rocks based on variable confining pressure, provided by a specific embodiment of the present invention;

[0059] Figure 7 This is a schematic diagram of the structure of the acoustic-mechanical measurement MTS device provided in a specific embodiment of the present invention;

[0060] Figure 8 This is a test diagram of stress conditions for a variable confining pressure acoustic-force combined measurement experiment provided in a specific embodiment of the present invention;

[0061] Figure 9 This is a stress-strain curve diagram of the cyclic rise segment of deviatoric stress under different confining pressures provided by a specific embodiment of the present invention.

[0062] Figure 10 This is a waveform diagram of the peak point of the deviatoric stress cycle under different confining pressure conditions provided by a specific embodiment of the present invention;

[0063] Figure 11 This is a cross-plot and regression fitting result diagram of the dynamic Young's modulus and the static Young's modulus provided in a specific embodiment of the present invention.

[0064] Figure 12 This is a schematic diagram of a device for characterizing the dynamic and static elastic parameters of rock based on variable confining pressure, provided in an embodiment of the present invention.

[0065] Figure 13 This is a schematic diagram of the structure of an electronic device provided in another embodiment of the present invention. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details are presented in the embodiments of the present invention to facilitate a better understanding of the invention. However, the technical solutions claimed in the present invention can be implemented even without these technical details and various variations and modifications based on the following embodiments. The division of the following embodiments is for ease of description and should not constitute any limitation on the specific implementation of the present invention. The various embodiments can be combined with and referenced by each other without contradiction.

[0067] The difference between dynamic and static elastic parameters usually stems from different loading conditions. Static elastic parameter testing, such as triaxial compression mechanics testing, typically involves strain amplitudes of 10... -3 up to 10 -5 Between these values, dynamic elastic parameter tests, such as elastic wave propagation, produce strain amplitudes less than 10. -6 These differences in strain amplitude lead to varying internal responses within the rock. In the fields of petroleum and geological engineering, accurately assessing the relationship between the dynamic and static elastic moduli of rocks is crucial for the effective development of resources and the stability of engineering projects. In oil and gas exploration and production, the dynamic elastic modulus is significant for predicting formation pore pressure, assessing wellbore stability, and optimizing fracturing design. The static elastic modulus plays a key role in evaluating reservoir quality and calculating formation stress. Researching the relationship between dynamic and static elastic moduli can provide scientific basis and technical support for numerous applications in petroleum and geological engineering.

[0068] Example 1:

[0069] Based on the above objectives and to solve at least some of the technical problems described in the background section of this invention, a method for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure, as described in this embodiment, can be applied to electronic devices with communication, computing, and data storage capabilities. Its specific process can be as follows: Figure 1 As shown, it includes:

[0070] Step 100: Determine the deviatoric stress loading amplitude based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features;

[0071] Step 200: Under multiple confining pressures, apply multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude;

[0072] Step 300: Measure the dynamic elastic parameters and static elastic parameters of the target rock during the application of the multi-level deviatoric stress, and determine the relationship between the dynamic elastic parameters and the static elastic parameters.

[0073] An embodiment of the present invention provides a method for characterizing the relationship between dynamic and static elastic parameters of rocks based on varying confining pressure, comprising: first, determining the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; then, applying multiple levels of deviatoric stress to the target rock under multiple confining pressures according to the deviatoric stress loading amplitude; finally, measuring the dynamic and static elastic parameters of the target rock during the application of multiple levels of deviatoric stress, and determining the relationship between the dynamic and static elastic parameters.

[0074] This invention determines a reasonable deviatoric stress loading amplitude, designs a multi-stage deviatoric stress cyclic loading scheme, and conducts acoustic-mechanical measurements to simultaneously acquire the dynamic and static elastic parameters of the rock. A model is established based on experimental data and corrected using triaxial compression test data to improve prediction accuracy. This invention effectively improves testing stability, provides accurate elastic modulus data for petroleum and geological engineering, and is of great significance for engineering design and construction safety.

[0075] For step 100, the deviatoric stress loading amplitude must be determined based on the rock type and physical characteristics (such as porosity, permeability, fracture parameters and structural features) of the target rock. It is necessary to comprehensively consider how these physical characteristics affect the mechanical properties of the rock and its response under different stress conditions.

[0076] The type of rock determines its basic mechanical properties. Different types of rocks (such as sandstone, shale, granite, limestone, etc.) exhibit significant differences in their performance under stress. Rock type affects parameters such as strength, elastic modulus, porosity, and permeability, all of which directly influence the amplitude of deviatoric stress loading.

[0077] Sandstone: Sandstone has high strength and elastic modulus, large porosity, and strong permeability. It may exhibit good plasticity under low stress, but it is prone to brittle fracture under high stress.

[0078] Shale: Shale has low strength and high brittleness, and its porosity and permeability are low, making it prone to cracking. Therefore, it is prone to shear fracture when subjected to deviatoric stress.

[0079] Granite: It has high hardness and compressive strength, exhibiting brittle fracture behavior. It has low porosity and extremely low permeability.

[0080] Limestone: It has high compressive strength and a large elastic modulus, but it is controlled by cracks and is prone to shear fracture.

[0081] Influence of physical characteristics on the amplitude of deviatoric stress:

[0082] Porosity is the ratio of pore volume to total volume in a rock. It reflects the porosity of the rock and directly affects its strength and deformation characteristics.

[0083] High porosity: When the porosity of a rock is high, its compressive strength is low, and it is easily subjected to compression and plastic deformation under deviatoric stress. High-porosity rocks (such as sandstone) may undergo irreversible compression or crack propagation under relatively low deviatoric stress.

[0084] Low porosity: Low-porosity rocks (such as granite) have high compressive strength and rigidity, but may also fracture brittlely under high deviatoric stress. Low-porosity rocks have a strong ability to withstand deviatoric stress during loading.

[0085] When determining the deviatoric stress amplitude, if the rock porosity is high, a lower deviatoric stress amplitude may need to be selected to avoid overcompression. If the porosity is low, a higher deviatoric stress can be applied.

[0086] Permeability is the ability of a rock to allow fluids to pass through it, and it is related to porosity and pore structure. Rocks with high permeability (such as sandstone) are more prone to pore compression or crack propagation under stress, thus affecting the magnitude of deviatoric stress loading.

[0087] High-permeability rocks: Rocks with high permeability (such as sandstone) are more prone to crack propagation when deviatoric stress is applied, which may lead to premature deviatoric stress-induced fracture. Therefore, a lower deviatoric stress loading amplitude needs to be selected.

[0088] Low-permeability rocks: Rocks with low permeability (such as shale and granite) are less prone to crack propagation, and therefore can be loaded under higher deviatoric stress.

[0089] Fracture parameters include fracture size, distribution, density, and morphology. Fractures significantly affect the mechanical behavior of rocks under deviatoric stress loading. The presence of fractures not only reduces the overall strength of the rock but can also become a source of deviatoric stress concentration and fracture.

[0090] Rocks with well-developed fissures (such as shale and weathered rocks) will experience crack propagation or shear fracture even under relatively low deviatoric stress. Therefore, for these types of rocks, the deviatoric stress amplitude should be appropriately reduced to avoid brittle fracture caused by fissures.

[0091] Rocks with fewer fissures (such as granite and hard limestone) can withstand higher deviatoric stress and often exhibit higher elastic deformation under load. However, they may also undergo brittle fracture when the deviatoric stress is large, so the loading amplitude can be relatively large.

[0092] Tectonic features include the bedding, joints, and folds of rocks. These features directly influence stress distribution and fracture modes under different stress environments.

[0093] Rocks with obvious bedding or joints, such as shale and sandstone, tend to slip or fracture along the weak surfaces when subjected to deviatoric stress due to the weakening along the bedding or joint directions. Therefore, when applying deviatoric stress to these rocks, it is necessary to select an appropriate amplitude to avoid fracture along the weak surfaces.

[0094] Rocks without obvious structural features, such as some homogeneous granites, are not prone to fracturing or sliding along structural planes. For these rocks, a larger deviatoric stress amplitude can be used for loading, and the rocks will exhibit higher strength under high stress.

[0095] Specifically, in step 100, the fracture stress of the rock can be calculated based on the Mohr-Coulomb fracture criterion, assuming that the fracture of the rock is controlled by the relationship between normal stress and shear stress. The Mohr-Coulomb criterion provides the relationship between the shear strength and normal stress of the rock:

[0096] t = c + σ·tan(φ)

[0097] Where: t is shear stress, σ is normal stress, c is the cohesion of the rock (related to the porosity and fracture structure of the rock), and φ is the internal friction angle (related to the structural characteristics and fracture density of the rock).

[0098] Based on the specific physical characteristics of the rock, the amplitude of the deviatoric stress under different stress states can be calculated.

[0099] Stress-strain curves of rocks under different stresses can be obtained through experiments or theoretical modeling. Different rocks exhibit different stress-strain behaviors.

[0100] High-porosity rocks: strain may be large, and the amplitude of the applied deviatoric stress is small.

[0101] Low-porosity rocks have smaller strain, allowing for larger deviatoric stress amplitudes under load.

[0102] In addition, different amplitudes of deviatoric stress can be gradually applied to the rock through experimental methods such as triaxial compression tests or uniaxial compression tests, and the fracture or yielding behavior of the rock can be observed. The appropriate deviatoric stress amplitude can then be deduced from the experimental data.

[0103] In summary, for rocks with high porosity and well-developed fractures, a lower deviatoric stress loading amplitude should be selected to avoid premature fracturing or fracture propagation. For rocks with low porosity, low permeability, and no obvious structural weaknesses, a higher deviatoric stress loading amplitude can be selected.

[0104] Porosity is the ratio of pore volume to total volume in a rock, reflecting the rock's porosity. Porosity directly affects the rock's strength, deformation characteristics, and permeability.

[0105] Permeability refers to the ability of a rock to allow fluid flow, and it is closely related to the rock's porosity and pore connectivity. Rocks with high permeability allow fluids to pass through more easily, which has a significant impact on the rock's performance under deviatoric stress loading.

[0106] Fracture parameters, including fracture density, distribution, size, and morphology, directly affect the fracture behavior of rocks under stress. Fractures have a significant impact on the mechanical properties of rocks, especially under deviatoric stress loading, where fractures can become stress concentration areas, easily leading to failure.

[0107] Rocks with numerous fissures may become the source of brittle fracture under deviatoric stress loading, thus requiring a smaller deviatoric stress amplitude to prevent fissure propagation and fracture. Rocks with fewer fissures, on the other hand, can maintain higher strength even under higher stress.

[0108] The structural features of rocks include geological structures such as bedding, joints, and folds. These structural features determine the deformation and fracture modes of rocks under deviatoric stress.

[0109] For step 200, based on the deviatoric stress loading amplitude determined in step 100, a multi-stage deviatoric stress cyclic loading scheme is designed. This scheme will include different confining pressure conditions, with a series of deviatoric stress cycles set under each confining pressure condition to simulate various stress environments that actual underground rocks may encounter. The amplitude, frequency, and duration of the cyclic loading must be carefully designed (which will be discussed later) to ensure the effectiveness and safety of the experiment.

[0110] Regarding step 300, the elastic parameters of the rock are important mechanical indicators describing the rock's ability to deform elastically under external forces, including the elastic modulus and Poisson's ratio.

[0111] The elastic modulus is a physical quantity that measures a material's resistance to deformation, representing the magnitude of strain produced per unit stress. For rocks, the elastic modulus mainly includes Young's modulus and shear modulus.

[0112] Young's modulus represents the stiffness of a rock under tension or compression; it is the ratio between stress and strain. It reflects the rock's ability to elastically deform. Young's modulus is closely related to the rock's mineral composition, porosity, fracture distribution, and moisture content. Rocks with higher porosity or more developed fractures exhibit lower Young's modulus.

[0113] Shear modulus describes the stiffness of a rock under shear force, representing the magnitude of shear strain caused by a unit shear stress. Shear modulus is closely related to the rock's mineral composition, density, porosity, and the nature of its fractures. Harder and denser rocks (such as granite and basalt) have higher shear moduli, while rocks with high porosity (such as sandstone and shale) have lower shear moduli.

[0114] Poisson's ratio describes the ratio of transverse strain to longitudinal strain in a rock under tension or compression. It is closely related to the deformation characteristics of rocks and is used to analyze stress distribution and deformation behavior under different loads. The Poisson's ratio of a rock is related to its composition, porosity, and structural features. For example, hard rocks (such as granite and basalt) have lower Poisson's ratios, while soft rocks (such as sandstone and shale) have relatively higher Poisson's ratios. Typical values ​​for Poisson's ratio:

[0115] Granite: 0.2-0.3;

[0116] Basalt: 0.25-0.3;

[0117] Sandstone: 0.25-0.4;

[0118] Shale: 0.3-0.4;

[0119] Limestone: 0.2-0.3;

[0120] The elastic parameters of rocks are affected by a variety of factors, mainly including the following:

[0121] Mineral composition: Different minerals have different elastic moduli. Generally speaking, dense and hard minerals (such as quartz and feldspar) have higher elastic moduli, while soft minerals (such as clay minerals and mica) have lower elastic moduli.

[0122] Porosity: Rocks with higher porosity exhibit lower elastic modulus. The effect of porosity on elastic modulus varies among different rock types, but the general trend is that as porosity increases, the elastic modulus decreases.

[0123] Fractures and structural features: Structural features such as fractures, bedding, and joints have a significant impact on the elastic behavior of rocks. Weak surfaces such as fractures and joints reduce the stiffness of rocks, thereby reducing the elastic modulus.

[0124] Moisture content: Rocks with higher moisture content exhibit lower elastic modulus. The presence of water can increase the plastic deformation behavior of rocks, making them more susceptible to deformation under stress.

[0125] Loading rate and temperature: Under high temperature or rapid loading conditions, the elastic modulus of rock may change. For example, the elastic modulus of rock decreases at high temperatures.

[0126] For step 300, based on the dynamic and static elastic parameter data obtained in step 200, a relationship model between the dynamic and static elastic parameters of the rock is established using statistical and numerical analysis methods. This model will describe how the dynamic elastic modulus of the rock is converted into the static elastic modulus under different confining pressures.

[0127] Example 2:

[0128] In some embodiments, step 200 includes:

[0129] Under each confining pressure, a series of deviatoric stress cycles are set according to the deviatoric stress loading amplitude to apply multiple levels of deviatoric stress to the target rock.

[0130] Specifically, a series of deviatoric stress cycles are set under each confining pressure condition to simulate the various stress environments that actual underground rocks may encounter.

[0131] In some embodiments, a method for characterizing the dynamic and static elastic parameter relationship of rocks based on varying confining pressure further includes:

[0132] The amplitude, frequency, and duration of the deviatoric stress cycle are determined based on the rock type and the physical characteristics.

[0133] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0134] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0135] In some embodiments, see Figure 2 Step 300, "measuring the static elastic parameters of the target rock during the application of the multi-level deviatoric stress," includes:

[0136] Step 301: During the multi-level deviatoric stress process, a triaxial compression test is performed on the target rock to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0137] Specifically, confining pressure was applied to the rock sample in three orthogonal directions, followed by axial pressure until failure, and the stress-strain relationship was measured during this process. The static elastic modulus was determined by the slope of the initial linear stress-strain curve, while Poisson's ratio was obtained by measuring the ratio of axial strain to lateral strain.

[0138] Step 302: Determine the static Poisson's ratio and the static Young's modulus based on the axial stress, axial strain, and radial strain.

[0139] In a uniaxial compression test, the static Young's modulus (E1) is the sum of the axial stress (σ) and the resulting axial strain (ε). a The ratio between ) and ), where the static Poisson's ratio (υ1) is negative, is the radial strain (ε) caused by axial stress. r ) and axial strain (ε a The ratios between them are shown in equations (1) and (2):

[0140]

[0141] In some embodiments, see Figure 3 Step 300, "measuring the dynamic elastic parameters of the target rock during the application of the multi-level deviatoric stress," includes:

[0142] Step 303: During the multi-level deviatoric stress process, the target rock is subjected to ultrasonic testing to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0143] Specifically, the dynamic elastic properties of rocks can be assessed by measuring the propagation velocities of longitudinal and transverse waves. Wave velocity is related to the density and elastic modulus of the rock, and the dynamic elastic modulus of the rock can be calculated from the wave velocity and density.

[0144] Step 304: Determine the dynamic Poisson's ratio based on the longitudinal wave velocity and the transverse wave velocity;

[0145] Step 305: Determine the dynamic Young's modulus based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0146] In steps 304 and 305, based on the wave equation (Zhang et al., 2021), the propagation speed of elastic waves in a solid medium can be used to calculate the elastic parameters of the rock, which are called dynamic elastic parameters (Mavko et al., 2009).

[0147] Assuming that the volume density (ρ) of the sample remains constant during stress loading, the formulas for calculating the dynamic Poisson's ratio (υ2) and the dynamic Young's modulus (E2) are shown in (3) and (4).

[0148]

[0149] In some embodiments, see Figure 4 Following step 300, a method for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure further includes:

[0150] Step 400: Determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure;

[0151] Step 500: Correct the relationship between the dynamic elastic parameter and the static elastic parameter according to the ratio.

[0152] In steps 400 and 500, the static Young's modulus E during the triaxial compression failure process is calculated. P The static Young's modulus E calculated by cyclic deviatoric stress under the same confining pressure. C The ratio of is used to correct the static Young's modulus under other confining pressure conditions. The correction formula is as follows:

[0153] E new =E P / E C *E (5)

[0154] An embodiment of the present invention provides a method for characterizing the relationship between dynamic and static elastic parameters of rocks based on varying confining pressure, comprising: first, determining the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; then, applying multiple levels of deviatoric stress to the target rock under multiple confining pressures according to the deviatoric stress loading amplitude; finally, measuring the dynamic and static elastic parameters of the target rock during the application of multiple levels of deviatoric stress, and determining the relationship between the dynamic and static elastic parameters.

[0155] This invention provides a method for characterizing the dynamic and static elastic parameters of rocks based on variable confining pressure. Through innovative multi-level deviatoric stress cyclic loading under variable confining pressure, it significantly improves the accuracy and reliability of predicting the dynamic and static elastic modulus of rocks. By controlling the loading of confining pressure and deviatoric stress, and simultaneously acquiring the dynamic and static elastic parameters of rocks under different confining pressure conditions, a dynamic and static elastic parameter relationship model under different confining pressures is established. Finally, by matching the model with the elastic modulus obtained from triaxial compression experiments, the corrected static elastic modulus of rocks under variable confining pressure conditions is obtained, thus completing the correction of the dynamic and static elastic parameter relationship model.

[0156] This method not only optimizes the selection of stress amplitude but also effectively reduces the impact of rock sample heterogeneity on test results. Furthermore, through acoustic-mechanical combined testing experiments and the establishment of a dynamic-static elastic parameter relationship model, this invention can accurately calibrate dynamic-static test models, providing reliable data support for rock mechanics research and geological engineering practice.

[0157] Example 3:

[0158] For further explanation of the plan, see Figure 5 as well as Figure 6 The present invention also provides a specific implementation of a method for characterizing the relationship between dynamic and static elastic parameters of rocks based on variable confining pressure, which specifically includes the following contents.

[0159] This invention relates to the field of rock mechanics, and in particular to a method for predicting the dynamic and static elastic modulus of rocks under different confining pressures. Primarily aimed at addressing the problems of testing instability caused by the heterogeneity of rock samples, difficulty in selecting the deviatoric stress amplitude, and inaccuracy of dynamic and static testing models, this method uses rock mechanics and acoustic experiments with controlled multi-level deviatoric stress cyclic loading under confining pressure to predict the dynamic and static elastic modulus relationship of rocks under different confining pressures.

[0160] S1: Determine the magnitude of the deviatoric stress loading.

[0161] In this step, a reasonable deviatoric stress loading amplitude is first estimated through a preliminary analysis of the rock's physical properties, combined with empirical data or test results of similar rock types in the literature (or determined using the aforementioned method). Subsequently, a preliminary test is conducted on the rock sample using uniaxial compression experiments to determine its mechanical response. The experimental data will be used to verify the suitability of the preset deviatoric stress amplitude, ensuring that the nonlinear properties of the rock are stimulated during subsequent multi-stage deviatoric stress cyclic loading without causing sample damage.

[0162] S2: Set up multi-level variable confining pressure deviatoric stress cycle.

[0163] Based on the deviatoric stress loading amplitude determined in step S1, a multi-stage deviatoric stress cyclic loading scheme is designed. This scheme will include different confining pressure conditions, with a series of deviatoric stress cycles set under each confining pressure condition to simulate various stress environments that actual underground rocks may encounter. The amplitude, frequency, and duration of the cyclic loading must be carefully designed to ensure the effectiveness and safety of the experiment.

[0164] In this experiment, the MTS 815 servo-hydraulic rock mechanics testing system was used. Figure 7 This system can simultaneously test dynamic and static elastic parameters. This advanced testing system boasts a powerful load capacity, with a maximum axial compressive strength of 4600 kN, a maximum tensile strength of 2300 kN, and maximum pore pressure and confining pressure both reaching 140 MPa.

[0165] The core components of the system are located in the triaxial chamber, including a load cell for measuring deviatoric stress, a titanium alloy ultrasonic probe equipped with longitudinal and transverse wave piezoelectric ceramic transducers, and axial and circumferential extensometers for measuring axial and radial deformation. These sophisticated components work together to ensure the accuracy and reliability of the experimental data.

[0166] A multi-stage deviatoric stress cyclic experimental procedure was employed to simulate the in-situ effective stress conditions of the rock in the study area. Specifically, the confining pressures were set to 10 MPa, 20 MPa, and 30 MPa. Figure 8 The maximum deviatoric stress amplitude was set to 30 MPa to simulate the in-situ effective vertical stress of the formation. During the deviatoric stress loading process, a constant stress rate of 0.2 kN / s was controlled to ensure the consistency and repeatability of the loading process.

[0167] S3: Conduct acoustic-mechanical joint measurement experiments.

[0168] An acoustic-mechanical combined experiment was conducted on rock samples using the MTS815 rock mechanics testing system. During the experiment, the mechanical response (e.g., stress-strain data) and acoustic response (e.g., P-wave and S-wave velocities) of the rock were simultaneously acquired by precisely controlling the confining pressure and deviatoric stress. Accurate recording and real-time monitoring of all parameters were ensured throughout the experiment to obtain high-quality data.

[0169] S4: Establish a model of the relationship between dynamic and static elastic parameters.

[0170] Based on the dynamic and static elastic parameter data obtained in step 3, a relationship model between the dynamic and static elastic parameters of the rock is established using statistical and numerical analysis methods. This model will describe how the dynamic elastic modulus of the rock is converted into the static elastic modulus under different confining pressures.

[0171] At the end of the deviatoric stress cycle, while keeping the confining pressure constant, the stress loading method was changed, and a displacement control mode close to the constant strain rate was adopted to conduct a triaxial compression test on the rock. During the experiment, the deviatoric stress, axial deformation, and radial deformation were monitored in real time, and the stress-strain curves of the rock under different confining pressures were obtained. Figure 9 The static elastic parameters of the rock were calculated using formulas (1) and (2). Furthermore, longitudinal and transverse wave signals of the rock were collected each time the maximum deviatoric stress was reached. Figure 10 By combining the density information of the rock sample, the dynamic elastic parameters of the rock can be calculated using formulas (3) and (4).

[0172] Through experimental testing of multiple sets of rocks, multiple regression analysis can be performed based on the obtained dynamic and static elastic parameters to obtain the relationship models of dynamic and static elastic parameters under different confining pressures. Figure 11 ).

[0173] S5: Correction of dynamic and static elastic parameter relationship model.

[0174] The ratio of the static modulus obtained from triaxial compression experiments to the static modulus calculated from deviatoric stress cycles under the same confining pressure is used as the correction coefficient for the dynamic-static relationship model under varying confining pressure. After correction, the final determined dynamic-static elastic parameter relationship model is used to predict the dynamic-static elastic modulus of rock under varying confining pressure.

[0175] The dynamic elastic parameters of the rock, including Young's modulus and Poisson's ratio, can be calculated. Combined with formula (5), the static modulus under different confining pressures can be calculated after correction.

[0176] The present invention provides a method for characterizing the relationship between dynamic and static elastic parameters of rocks based on varying confining pressure, comprising: first, determining the deviatoric stress loading amplitude according to the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; then, applying multiple levels of deviatoric stress to the target rock under multiple confining pressures according to the deviatoric stress loading amplitude; finally, measuring the dynamic and static elastic parameters of the target rock during the application of multiple levels of deviatoric stress, and determining the relationship between the dynamic and static elastic parameters.

[0177] Specifically, this invention designs a multi-stage deviatoric stress cyclic loading scheme by determining a reasonable deviatoric stress loading amplitude (which can be determined through empirical judgment or uniaxial compressive strength tests, and then setting the cyclic amplitude of multi-stage deviatoric stress cycles), and uses an MTS815 rock mechanics testing device for acoustic-mechanical joint measurement to simultaneously acquire the dynamic and static elastic parameters of the rock. A model is established based on the experimental data and corrected using triaxial compression test data to improve the accuracy of predictions. This method effectively improves test stability, provides accurate elastic modulus data for petroleum and geological engineering, and is of great significance for engineering design and construction safety.

[0178] Example 4:

[0179] Another embodiment of the present invention relates to a device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure. The implementation details of this embodiment of the device are described below. The following details are provided for ease of understanding and are not essential for implementing this solution. A schematic diagram of this embodiment of the device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure can be seen as follows: Figure 12 As shown, the device includes: a deviatoric stress loading amplitude determination module 801, a multi-level deviatoric stress application module 802, and a relationship determination module 803.

[0180] The deviatoric stress loading amplitude determination module 801 is used to determine the deviatoric stress loading amplitude based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters and structural features;

[0181] The multi-level deviatoric stress application module 802 is used to apply multi-level deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures.

[0182] The relationship determination module 803 is used to measure the dynamic elastic parameters and static elastic parameters of the target rock during the application of the multi-level deviatoric stress, and to determine the relationship between the dynamic elastic parameters and the static elastic parameters.

[0183] In some embodiments, the multi-level deviatoric stress application module includes:

[0184] A multi-level deviatoric stress application unit is used to set a series of deviatoric stress cycles according to the deviatoric stress loading amplitude under each confining pressure in order to apply multi-level deviatoric stress to the target rock.

[0185] In some embodiments, a device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure further includes:

[0186] The deviatoric stress cycle parameter determination module is used to determine the amplitude, frequency, and duration of the deviatoric stress cycle process based on the rock type and the physical characteristics.

[0187] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0188] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0189] In some embodiments, the relationship determination module includes:

[0190] A stress-strain determination unit is used to perform triaxial compression tests on the target rock during the multi-level deviatoric stress process to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0191] The static elastic parameter determination unit is used to determine the static Poisson's ratio and the static Young's modulus based on the axial stress, axial strain, and radial strain.

[0192] In some embodiments, the relationship determination module further includes:

[0193] A velocity determination unit is used to perform ultrasonic testing on the target rock during the multi-level deviatoric stress process to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0194] A dynamic Poisson ratio determination unit is used to determine the dynamic Poisson ratio based on the longitudinal wave velocity and the transverse wave velocity;

[0195] The dynamic Young's modulus determination unit is used to determine the dynamic Young's modulus based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0196] In some embodiments, a device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure further includes:

[0197] The ratio determination module is used to determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure.

[0198] The relationship correction module is used to correct the relationship between the dynamic elastic parameter and the static elastic parameter based on the ratio.

[0199] An embodiment of the present invention provides a device for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure, comprising: an initial realized value generation module for generating multiple initial realized values ​​of fitting parameters for a tight gas reservoir; wherein the fitting parameters are used to characterize the time-varying features of the tight gas reservoir; an iterative operation module for performing the following iterative operations until the posterior distribution of the current parameter field meets the expected value and the initial realized values ​​corresponding to all fitting parameters are assimilated; a parameter length generation module for performing historical fitting on multiple current geological models of the tight gas reservoir based on the multiple current realized values ​​to generate a current parameter field; wherein the initial value of the current realized value is the initial realized value, and the current geological model is generated by the current parameter field and the previous geological model; and a posterior distribution calculation module for calculating the posterior distribution of the current parameter field.

[0200] This invention takes into account the fact that the probability distribution of the property field of tight gas reservoirs is usually a complex multi-peak distribution, and solves the problem of difficulty in conducting numerical simulations of multi-peak fields. In addition, this invention can realize the simulation of time-varying characteristics of parameters. Tight gas has initiation pressure and stress sensitivity. As mining progresses, the pressure continuously decreases, and formation water is extracted. Initiation pressure and stress sensitivity are quantities that change with time. The fitting method provided by this invention can achieve variable field fitting.

[0201] It is worth mentioning that all modules involved in this embodiment are logical modules. In practical applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. Furthermore, to highlight the innovative aspects of this invention, this embodiment does not introduce units that are not closely related to solving the technical problem proposed by this invention; however, this does not mean that other units are absent from this embodiment.

[0202] Example 5:

[0203] Another embodiment of the present invention relates to an electronic device, such as Figure 13 As shown, the electronic device specifically includes the following:

[0204] Processor 1201, memory 1202, communications interface 1203, and bus 1204;

[0205] The processor 1201, memory 1202, and communication interface 1203 communicate with each other via bus 1204; the communication interface 1203 is used to realize information transmission between server-side devices and user-side devices and other related devices.

[0206] The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, it implements all the steps in the rock dynamic and static elastic parameter relationship characterization method based on variable confining pressure in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0207] The deviatoric stress loading amplitude is determined based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features;

[0208] Under multiple confining pressures, multiple levels of deviatoric stress are applied to the target rock according to the deviatoric stress loading amplitude;

[0209] The dynamic and static elastic parameters of the target rock are measured during the application of the multi-level deviatoric stress, and the relationship between the dynamic and static elastic parameters is determined.

[0210] In some embodiments, applying multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures includes:

[0211] Under each confining pressure, a series of deviatoric stress cycles are set according to the deviatoric stress loading amplitude to apply multiple levels of deviatoric stress to the target rock.

[0212] In some embodiments, a method for characterizing the dynamic and static elastic parameter relationship of rocks based on varying confining pressure further includes:

[0213] The amplitude, frequency, and duration of the deviatoric stress cycle are determined based on the rock type and the physical characteristics.

[0214] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0215] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0216] In some embodiments, measuring the static elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0217] During the multi-level deviatoric stress process, the target rock is subjected to triaxial compression testing to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0218] The static Poisson's ratio and the static Young's modulus are determined based on the axial stress, axial strain, and radial strain.

[0219] In some embodiments, measuring the dynamic elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0220] During the multi-level deviatoric stress process, the target rock is subjected to ultrasonic testing to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0221] The dynamic Poisson's ratio is determined based on the longitudinal wave velocity and the transverse wave velocity;

[0222] The dynamic Young's modulus is determined based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0223] In some embodiments, after measuring the dynamic and static elastic parameters of the target rock during the application of the multi-level deviatoric stress and determining the relationship between the dynamic and static elastic parameters, the method further includes:

[0224] Determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure;

[0225] The relationship between the dynamic elastic parameter and the static elastic parameter is corrected based on the ratio.

[0226] The memory and processor are connected via a bus, which can include any number of interconnecting buses and bridges, connecting various circuits of one or more processors and memories. The bus can also connect various other circuits, such as peripheral devices, voltage regulators, and power management circuits, which are well known in the art and will not be described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single element or multiple elements, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over the wireless medium via an antenna, which further receives data and transmits it to the processor.

[0227] The processor manages the bus and general processing, and also provides various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory is used to store data used by the processor during operation.

[0228] Example 6:

[0229] Another embodiment of the present invention relates to a computer-readable storage medium storing a computer program. When executed by a processor, the computer program implements the steps in the above-described embodiment of the method for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure. These steps include:

[0230] The deviatoric stress loading amplitude is determined based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features;

[0231] Under multiple confining pressures, multiple levels of deviatoric stress are applied to the target rock according to the deviatoric stress loading amplitude;

[0232] The dynamic and static elastic parameters of the target rock are measured during the application of the multi-level deviatoric stress, and the relationship between the dynamic and static elastic parameters is determined.

[0233] In some embodiments, applying multiple levels of deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures includes:

[0234] Under each confining pressure, a series of deviatoric stress cycles are set according to the deviatoric stress loading amplitude to apply multiple levels of deviatoric stress to the target rock.

[0235] In some embodiments, a method for characterizing the dynamic and static elastic parameter relationship of rocks based on varying confining pressure further includes:

[0236] The amplitude, frequency, and duration of the deviatoric stress cycle are determined based on the rock type and the physical characteristics.

[0237] In some embodiments, the dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus;

[0238] The static elastic parameters include: static Poisson's ratio and static Young's modulus.

[0239] In some embodiments, measuring the static elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0240] During the multi-level deviatoric stress process, the target rock is subjected to triaxial compression testing to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress.

[0241] The static Poisson's ratio and the static Young's modulus are determined based on the axial stress, axial strain, and radial strain.

[0242] In some embodiments, measuring the dynamic elastic parameters of the target rock during the application of the multi-level deviatoric stress includes:

[0243] During the multi-level deviatoric stress process, the target rock is subjected to ultrasonic testing to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process.

[0244] The dynamic Poisson's ratio is determined based on the longitudinal wave velocity and the transverse wave velocity;

[0245] The dynamic Young's modulus is determined based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

[0246] In some embodiments, after measuring the dynamic and static elastic parameters of the target rock during the application of the multi-level deviatoric stress and determining the relationship between the dynamic and static elastic parameters, the method further includes:

[0247] Determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure;

[0248] The relationship between the dynamic elastic parameter and the static elastic parameter is corrected based on the ratio.

[0249] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on its differences from other embodiments. In particular, hardware + program embodiments are relatively simple in description because they are fundamentally similar to method embodiments; relevant parts can be referred to the descriptions in the method embodiments.

[0250] The foregoing has described specific embodiments of this specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired result. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0251] While this invention provides method operation steps as shown in the embodiments or flowcharts, more or fewer operation steps may be included based on conventional or non-inventive labor. The order of steps listed in the embodiments is merely one possible execution order among many and does not represent the only possible execution order. In actual device or client product execution, the method can be executed in the order shown in the embodiments or drawings or in parallel (e.g., in a parallel processor or multi-threaded processing environment).

[0252] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0253] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0254] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0255] Specific embodiments have been used to illustrate the principles and implementation methods of this invention. The descriptions of the embodiments above are only for the purpose of helping to understand the method and core ideas of this invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this invention. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for characterizing the dynamic and static elastic parameter relationship of rocks based on variable confining pressure, characterized in that, include: The deviatoric stress loading amplitude is determined based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; Under multiple confining pressures, multi-level deviatoric stresses are applied to the target rock according to the deviatoric stress loading amplitude; The dynamic and static elastic parameters of the target rock are measured during the application of the multi-level deviatoric stress, and the relationship between the dynamic and static elastic parameters is determined.

2. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to claim 1, characterized in that, The process of applying multiple levels of deviatoric stress to the target rock under multiple confining pressures according to the deviatoric stress loading amplitude includes: Under each confining pressure, a series of deviatoric stress cycles are set according to the deviatoric stress loading amplitude to apply multiple levels of deviatoric stress to the target rock.

3. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to claim 2, characterized in that, Also includes: The amplitude, frequency, and duration of the deviatoric stress cycle are determined based on the rock type and the physical characteristics.

4. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to claim 1, characterized in that, The dynamic elastic parameters include: dynamic Poisson's ratio and dynamic Young's modulus; The static elastic parameters include: static Poisson's ratio and static Young's modulus.

5. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to claim 4, characterized in that, The measurement of the static elastic parameters of the target rock during the application of the multi-level deviatoric stress includes: During the multi-level deviatoric stress process, the target rock is subjected to triaxial compression testing to determine the axial stress, axial strain, and radial strain of the target rock during the multi-level deviatoric stress process; wherein the radial strain is caused by negative axial stress. The static Poisson's ratio and the static Young's modulus are determined based on the axial stress, axial strain, and radial strain.

6. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to any one of claims 1 to 5, characterized in that, The measurement of the dynamic elastic parameters of the target rock during the application of the multi-level deviatoric stress includes: During the multi-level deviatoric stress process, the target rock is subjected to ultrasonic testing to determine the longitudinal wave velocity and transverse wave velocity of the target rock during the multi-level deviatoric stress process. The dynamic Poisson's ratio is determined based on the longitudinal wave velocity and the transverse wave velocity; The dynamic Young's modulus is determined based on the bulk density of the target rock, the longitudinal wave velocity, and the dynamic Poisson's ratio.

7. The method for characterizing the relationship between dynamic and static elastic parameters of rock according to claim 5, characterized in that, After measuring the dynamic and static elastic parameters of the target rock during the application of the multi-level deviatoric stress and determining the relationship between the dynamic and static elastic parameters, the method further includes: Determine the ratio between the static modulus during the triaxial compression test and the static modulus determined by the deviatoric stress cycle under the same confining pressure; The relationship between the dynamic elastic parameter and the static elastic parameter is corrected based on the ratio.

8. A device for characterizing the dynamic and static elastic parameter relationship of rock based on variable confining pressure, characterized in that, include: The deviatoric stress loading amplitude determination module is used to determine the deviatoric stress loading amplitude based on the rock type and physical characteristics of the target rock; wherein, the physical characteristics include: porosity, permeability, fracture parameters, and structural features; A multi-level deviatoric stress application module is used to apply multi-level deviatoric stress to the target rock according to the deviatoric stress loading amplitude under multiple confining pressures. The relationship determination module is used to measure the dynamic elastic parameters and static elastic parameters of the target rock during the application of the multi-level deviatoric stress, and to determine the relationship between the dynamic elastic parameters and the static elastic parameters.

9. An electronic device, characterized in that, include: At least one processor; as well as, A memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor to enable the at least one processor to perform the rock dynamic and static elastic parameter relationship characterization method based on variable confining pressure as described in any one of claims 1 to 7.

10. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for characterizing the relationship between dynamic and static elastic parameters of rock based on variable confining pressure, as described in any one of claims 1 to 7.

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