Rock mechanics dynamic and static conversion model construction method without damaging rock core, equipment, medium and product

Abstract

The invention discloses a rock mechanics dynamic-static conversion model construction method without damaging a rock core, equipment, a medium and a product, and relates to the field of rock mechanics, a group of rock samples are obtained, each rock sample is regarded as being composed of different sub-samples, the wave velocity and the volume density of each sub-sample meet normal distribution, and the wave velocity and the volume density of each sub-sample meet normal distribution; the standard deviation and the expected value are determined by the wave velocity and volume density experimental values of the group of rock samples. Substituting the wave velocity and the volume density of each generated sub-sample into a rock mechanical parameter physical model, calculating static mechanical parameters and dynamic mechanical parameters of the rock sample, and constructing a dynamic-static conversion model; performing stratigraphic section rock mechanical property analysis according to the dynamic-static conversion model; the rock mechanical parameter physical model is a theoretical relationship between the mechanical parameters of the rock sample and the mechanical parameters of each sub-sample. The dynamic and static conversion model is obtained by linear fitting of dynamic mechanical parameters and static mechanical parameters. The dynamic and static conversion model is constructed under the condition of no damage to the rock core, and the rock core utilization rate is increased.

Description

Technical Field

[0001] The present application relates to the field of rock mechanics, and in particular to a method, equipment, medium and product for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core. Background Art

[0002] Rock mechanics parameters can be divided into static mechanics parameters and dynamic mechanics parameters. Static mechanics parameters mainly refer to the properties and behaviors of rocks under static loads, such as the compressive strength, tensile strength, and shear strength of rocks; while dynamic mechanics parameters involve the response characteristics of rocks under dynamic loads, such as the wave velocity and wave impedance of rocks. The study of these two parameters is of great significance to rock engineering and geological exploration, and can help engineers and researchers more accurately evaluate the properties and behaviors of rocks, and provide a reliable basis for engineering design and construction.

[0003] In practical applications, the parameters used in drilling engineering and fracturing engineering are all obtained through static rock mechanics parameter calculations. Static mechanics parameters are mainly obtained by conducting triaxial compression experiments in rock chambers. However, due to the limited number of rock samples and the impact of mining costs, the experimental data is limited. Dynamic mechanical parameters are obtained by measuring the propagation speed of ultrasound in rock samples and using theoretical formulas. Compared with static mechanical parameters, dynamic mechanical parameter data is more comprehensive and complete, and can characterize the continuous change trend of mechanical parameters under actual formation environments. Therefore, it is of great significance to study the dynamic-static conversion model, which can provide a more scientific and reliable basis for the design, construction and prediction of rock engineering, and promote the development and progress of the field of rock engineering.

[0004] Currently, many scholars have conducted many experiments on different rock areas, and the studies have found that dynamic and static parameters are closely related. In 2007, Liu Jiangping, Luo Yinhe and others studied the correlation between dynamic and static Young's parameters of clay and found that the static Young's modulus is generally smaller than the dynamic Young's modulus. In 2015, Bian Huiyuan, Wang Fei and others studied the mechanical properties of tight sandstone under simulated reservoir conditions in the Sulige gas field and found that the dynamic Young's modulus is greater than the static Young's modulus, while there is no obvious correlation between the dynamic and static Poisson's ratios. In 2019, He Xiaodong, Ma Junxiu and others conducted a mechanical analysis of the conglomerate reservoir of the Mahu Oilfield and found that the dynamic and static Young's modulus have a good correlation, but the correlation between the dynamic and static Poisson's ratios is low.

[0005] Due to the heterogeneity of experimental rock samples and the small number of available samples, it is difficult to obtain static mechanical parameters and the experimental errors are relatively obvious, which makes it difficult for the dynamic-static conversion model to achieve the expected ideal effect. Therefore, it is urgent to develop a new dynamic-static conversion model to improve the accuracy of mechanical parameter conversion and provide a more accurate and reliable reference for the development and practical application of rock engineering. Summary of the invention

[0006] The purpose of this application is to provide a method, equipment, medium and product for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core, so as to improve the accuracy of mechanical parameter conversion.

[0007] To achieve the above objectives, this application provides the following solutions:

[0008] In a first aspect, the present application provides a method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core, comprising:

[0009] Based on ultrasonic waves, static mechanical parameters and dynamic mechanical parameters of a group of rock samples are obtained; the static mechanical parameters include static Young's modulus and static Poisson's ratio; the dynamic mechanical parameters include dynamic Young's modulus and dynamic Poisson's ratio; the static mechanical parameters and dynamic mechanical parameters are determined by using a rock mechanical parameter physical model; the rock mechanical parameter physical model is a theoretical relationship between the mechanical parameters of a rock sample and the mechanical parameters of each sub-sample; the sub-samples are obtained by evenly dividing the physical model of the rock sample; the rock mechanical parameter physical model includes a physical model of dynamic Young's modulus, a physical model of static Young's modulus, a physical model of dynamic Poisson's ratio and a physical model of static Poisson's ratio;

[0010] According to the static mechanical parameters and dynamic mechanical parameters of a group of rock samples, a rock mechanics dynamic-static conversion model is constructed; the rock mechanics dynamic-static conversion model includes a Young's modulus dynamic-static conversion model and a Poisson's ratio dynamic-static conversion model; the Young's modulus dynamic-static conversion model is obtained by linearly fitting the dynamic Young's modulus calculated based on a physical model of the dynamic Young's modulus and the static Young's modulus calculated based on a physical model of the static Young's modulus; the Poisson's ratio dynamic-static conversion model is obtained by linearly fitting the dynamic Poisson's ratio calculated based on a physical model of the dynamic Poisson's ratio and the static Poisson's ratio calculated based on a physical model of the static Poisson's ratio;

[0011] The dynamic mechanical parameters of the single well profile obtained during the logging process are obtained, and the static mechanical parameters of the formation profile are determined using the rock mechanics dynamic-static conversion model to perform rock mechanical property analysis of the formation profile.

[0012] Optionally, based on ultrasound, a set of static mechanical parameters and dynamic mechanical parameters of rock samples are obtained, specifically including:

[0013] Obtain a group of rock samples, divide the rock samples into n rock sub-samples, and obtain the volume density of the rock sub-samples; each rock sub-sample has the same thickness;

[0014] determining the shear wave velocity and the longitudinal wave velocity of the ultrasonic wave penetrating each layer of the rock subsample;

[0015] According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic mechanical parameters and static mechanical parameters of the rock sample are determined using a rock mechanical parameter physical model; the mechanical parameters include Young's modulus and Poisson's ratio.

[0016] Optionally, according to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the static mechanical parameters and dynamic mechanical parameters of the rock sample are determined by using a rock mechanical parameter physical model, specifically including:

[0017] According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic Young's modulus and the static Young's modulus of the rock sample are determined by using the physical model of the dynamic Young's modulus and the physical model of the static Young's modulus;

[0018] According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample, the dynamic Poisson's ratio and the static Poisson's ratio of the rock sample are determined by using the physical model of the dynamic Poisson's ratio and the physical model of the static Poisson's ratio.

[0019] Optionally, according to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic Young's modulus and the static Young's modulus of the rock sample are determined by using a physical model of the dynamic Young's modulus and a physical model of the static Young's modulus, specifically including:

[0020] Physical Model Using Dynamic Young's Modulus determining a dynamic Young's modulus of the rock sample;

[0021] Physical Model Using Static Young's Modulus determining a static Young's modulus of the rock sample;

[0022] Among them, E d is the dynamic Young's modulus of the rock sample; E s is the static Young's modulus of the rock sample; E i is the Young's modulus of the rock subsample in the i-th layer. i is the volume density of the rock subsample in the i-th layer; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

[0023] Optionally, according to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample, the dynamic Poisson's ratio and the static Poisson's ratio of the rock sample are determined by using a physical model of the dynamic Poisson's ratio and a physical model of the static Poisson's ratio, specifically including:

[0024] Physical Model Using Dynamic Poisson's Ratio determining a dynamic Poisson's ratio of the rock sample;

[0025] Physical Model Using Static Poisson's Ratio determining a static Poisson's ratio of the rock sample;

[0026] Among them, μ d is the dynamic Poisson's ratio of the rock sample; μ s is the static Poisson's ratio of the rock sample; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

[0027] Optionally, the dynamic-static conversion model of Young's modulus is:

[0028] E s '=a 1 ·E d '+b 1 ; Among them, E d ' is the dynamic Young's modulus of the single well profile obtained during the logging process; E s ' is the static Young's modulus of the formation section; a 1 is the first proportionality coefficient; b 1 is the first constant term.

[0029] Optionally, the Poisson's ratio dynamic-static conversion model is:

[0030] μ s '=a 2 ·μ d '+b 2 ; where μ d ' is the dynamic Poisson's ratio of the single well profile obtained during the logging process; μ s ' is the static Poisson's ratio of the stratigraphic section; a 2 is the second proportional coefficient; b 2 is the second constant term.

[0031] In a second aspect, the present application provides a computer device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the above-described methods for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core.

[0032] In a third aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements any of the above-mentioned methods for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core.

[0033] In a fourth aspect, the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned methods for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core.

[0034] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0035] The present application provides a method, equipment, medium and product for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core. First, for a group of rock samples, each rock sample is regarded as consisting of different homogeneous sub-samples. The wave velocity and volume density of each sub-sample satisfy the normal distribution, and its standard deviation and expected value are determined by the experimental values ​​of the wave velocity and volume density of the group of rock samples. Substitute the generated wave velocity and volume density values ​​of each sub-sample into the rock mechanics physical model, calculate the static Young's modulus and dynamic Young's modulus of the rock sample, and construct a dynamic-static conversion model; analyze the rock mechanical properties of the formation section according to the dynamic-static conversion model; the rock mechanics physical model is the theoretical relationship between the mechanical parameters of the rock sample and the mechanical parameters of each sub-sample. The dynamic-static conversion model is obtained by linear fitting of the dynamic mechanical parameters and the static mechanical parameters. The present application constructs a dynamic-static conversion model under non-destructive core conditions, improves the utilization rate of the core, and improves the accuracy of mechanical parameter conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 A schematic diagram of a flow chart of a method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to an embodiment of the present application;

[0038] Figure 2 A conventional experimental method provided in this application is used to construct a dynamic-static conversion model flow chart;

[0039] Figure 3 This is the curve diagram of the dynamic and static Young's modulus conversion model of Well A in the study area;

[0040] Figure 4 This is the curve diagram of the dynamic and static Poisson's ratio conversion model of Well A in the study area;

[0041] Figure 5 Schematic diagram of the physical model for dividing rock into sub-samples composed of n homogeneous thin rock layers;

[0042] Figure 6 This is a schematic diagram of the velocity model of ultrasonic waves passing through heterogeneous rocks;

[0043] Figure 7 Schematic diagram of the lateral stress and strain model caused by each homogeneous layer under axial compression;

[0044] Figure 8 A schematic diagram of the inversion results of inverting the static Young's modulus using the method of the present application and the conventional method;

[0045] Fig. 9 A schematic diagram of the inversion results of inverting the static Poisson's ratio using the method of the present application and the conventional method;

[0046] Fig.10 This is the result diagram of iterative operation of the dynamic-static conversion theoretical model program;

[0047] Fig.11 This is a comparison chart of the dynamic and static Young's modulus of the conventional method and the new method in Well A in the study area;

[0048] Fig.12 This is a comparison chart of the dynamic and static Poisson's ratios of the conventional method and the new method in Well A in the study area;

[0049] Fig.13 A schematic diagram of the structure of a computer device provided in one embodiment of the present application. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0052] In an exemplary embodiment, Figure 1 As shown, a method for constructing a dynamic-static conversion model of rock mechanics of a non-destructive core is provided, comprising:

[0053] S1: Based on ultrasound, static mechanical parameters and dynamic mechanical parameters of a group of rock samples are obtained; the static mechanical parameters include static Young's modulus and static Poisson's ratio; the dynamic mechanical parameters include dynamic Young's modulus and dynamic Poisson's ratio; the static mechanical parameters and dynamic mechanical parameters are determined using a rock mechanical parameter physical model; the rock mechanical parameter physical model is the theoretical relationship between the mechanical parameters of a rock sample and the mechanical parameters of each sub-sample; the sub-samples are obtained by evenly dividing the physical model of the rock sample; the rock mechanical parameter physical model includes a physical model of dynamic Young's modulus, a physical model of static Young's modulus, a physical model of dynamic Poisson's ratio and a physical model of static Poisson's ratio.

[0054] As an optional implementation, S1 specifically includes:

[0055] S11: Obtain a group of rock samples, divide the rock samples into n rock sub-samples, and obtain the volume density of the rock sub-samples; each rock sub-sample has the same thickness. The rock samples are divided into n homogeneous thin rock layer sub-samples (rock sub-samples).

[0056] S12: Determine the shear wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating each layer of the rock sub-sample. In practical applications, the wave velocity and density of the rock sub-sample are randomly formed and both satisfy the normal distribution, and their standard deviation and expected value are determined by the experimental values ​​of the wave velocity and volume density of the group of rock samples to generate the shear wave velocity and longitudinal wave velocity of the rock sub-sample.

[0057] S13: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic mechanical parameters and static mechanical parameters of the rock sample are determined by using the rock mechanical parameter physical model; the mechanical parameters include Young's modulus and Poisson's ratio. Specifically including:

[0058] S131: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic Young's modulus and the static Young's modulus of the rock sample are determined using the physical model of the dynamic Young's modulus and the physical model of the static Young's modulus.

[0059] Physical Model Using Dynamic Young's Modulus The dynamic Young's modulus of the rock sample is determined.

[0060] Physical Model Using Static Young's Modulus Determine the static Young's modulus of the rock sample.

[0061] Among them, E d is the dynamic Young's modulus of the rock sample; E s is the static Young's modulus of the rock sample; E iis the Young's modulus of the rock subsample in the i-th layer. i is the volume density of the rock subsample in the i-th layer; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

[0062] S132: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample, the dynamic Poisson's ratio and the static Poisson's ratio of the rock sample are determined using the physical model of the dynamic Poisson's ratio and the physical model of the static Poisson's ratio.

[0063] Physical Model Using Dynamic Poisson's Ratio Determine the dynamic Poisson's ratio of the rock sample.

[0064] Physical Model Using Static Poisson's Ratio Determine the static Poisson's ratio of the rock sample.

[0065] Among them, μ d is the dynamic Poisson's ratio of the rock sample; μ s is the static Poisson's ratio of the rock sample; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

[0066] S2: According to the static mechanical parameters and dynamic mechanical parameters of a group of rock samples, a rock mechanics dynamic-static conversion model is constructed; the rock mechanics dynamic-static conversion model includes a Young's modulus dynamic-static conversion model and a Poisson's ratio dynamic-static conversion model; the Young's modulus dynamic-static conversion model is obtained by linearly fitting the dynamic Young's modulus calculated based on the physical model of the dynamic Young's modulus and the static Young's modulus calculated based on the physical model of the static Young's modulus; the Poisson's ratio dynamic-static conversion model is obtained by linearly fitting the dynamic Poisson's ratio calculated based on the physical model of the dynamic Poisson's ratio and the static Poisson's ratio calculated based on the physical model of the static Poisson's ratio.

[0067] The dynamic-static conversion model of Young's modulus is:

[0068] E s '=a 1 ·E d '+b 1 ; Among them, E d ' is the dynamic Young's modulus of the single well profile obtained during the logging process; E s ' is the static Young's modulus of the formation section; a 1 is the first proportionality coefficient; b 1The first proportionality coefficient and the first constant term are determined based on the least squares linear fitting using the data of the dynamic Young's modulus of the rock sample and the data of the static Young's modulus of the rock sample.

[0069] The Poisson's ratio dynamic-static conversion model is:

[0070] μ s '=a 2 ·μ d '+b 2 ; where μ d ' is the dynamic Poisson's ratio of the single well profile obtained during the logging process; μ s ' is the static Poisson's ratio of the stratigraphic section; a 2 is the second proportional coefficient; b 2 The second proportionality coefficient and the second constant term are determined based on the least squares linear fitting using the data of the dynamic Poisson's ratio of the rock sample and the data of the static Poisson's ratio of the rock sample.

[0071] According to the rock mechanics dynamic-static conversion model construction method of the non-destructive core, the Young's modulus dynamic-static conversion model in this embodiment is:

[0072] E s '=1.242E d '-4.5605; where E d ' is the dynamic Young's modulus of the single well profile obtained during the logging process; E s ' is the static Young's modulus of the formation section.

[0073] The Poisson's ratio dynamic-static conversion model in this embodiment is:

[0074] μ s '=0.9034μ d '-0.0176; where μ d ' is the dynamic Poisson's ratio of the single well profile obtained during the logging process; μ s ' is the static Poisson's ratio of the stratigraphic section.

[0075] S3: Obtain the dynamic mechanical parameters of the single well profile obtained during the logging process, and determine the static mechanical parameters of the formation profile using the rock mechanics dynamic-static conversion model to perform rock mechanical property analysis of the formation profile.

[0076] Example 1.

[0077] like Figure 2 As shown in FIG. 1 , the process of establishing a dynamic-static conversion model by conventional experimental methods specifically includes:

[0078] Step 101: Select a suitable group of rock samples, obtain the longitudinal and transverse wave velocities of the rock samples through laboratory ultrasonic pulse testing, and calculate the dynamic mechanical parameters of the rock according to theoretical formulas. The mechanical parameters mainly include dynamic Young's modulus and dynamic Poisson's ratio.

[0079] As an optional implementation, step 101, before, also includes:

[0080] Rock samples are obtained by sampling rocks at different depths in the low-permeability reservoir. In practical applications, parallel sampling is used to select rocks with flat layers, large volumes, and no cracks in the study area (different depths in the low-permeability reservoir) for centralized sampling, ensuring that the influence of the rock properties of the rock samples themselves on the mechanical properties of the rock is minimized.

[0081] In this example, laboratory ultrasonic pulse tests were carried out on six rock samples from Well A in the study area without confining pressure to obtain the longitudinal and transverse wave velocities of the rock samples, and the dynamic Young's modulus and dynamic Poisson's ratio of the rocks were calculated according to theoretical formulas.

[0082] Follow the steps below to obtain the theoretical formula for calculating dynamic Young's modulus and Poisson's ratio:

[0083] According to elasticity theory, when the rock is isotropic and the wavelength of the sound wave is much smaller than the rock mass measurement scale, the longitudinal and transverse wave velocities have the following relationship:

[0084]

[0085] Where V P and V S are the longitudinal and transverse wave velocities of the rock sample (m / s); λ is the Lame constant; G is the shear modulus; ρ is the volume density of the rock sample (g / m 3 ).

[0086] According to the elasticity theory, the Lame constant λ, shear modulus G and bulk modulus K can be obtained:

[0087]

[0088] Where E is Young's modulus and μ is Poisson's ratio.

[0089] According to the above formula (1), formula (3) and formula (4), we can get:

[0090]

[0091] According to the above formula (2), formula (3) and formula (4), we can get:

[0092]

[0093] According to the above formula (6) and formula (7), the ratio is calculated and simplified to:

[0094]

[0095] According to formula (8), the calculation formula of dynamic Poisson's ratio is:

[0096]

[0097] Substituting the above relationship formula (9) into formula (7), the calculation formula of dynamic Young's modulus can be obtained after simplification:

[0098]

[0099] Step 102: Conduct an indoor triaxial compression test based on the rock sample to obtain a stress-strain curve; calculate the static mechanical parameters of the rock according to the stress-strain curve, wherein the mechanical parameters mainly include a static Young's modulus and a static Poisson's ratio.

[0100] As an optional implementation, step 102 specifically includes:

[0101] An indoor triaxial compression experiment is carried out based on the rock samples to obtain a stress-strain curve; the static mechanical parameters of the rock are calculated according to the stress-strain curve, and the mechanical parameters mainly include a static Young's modulus and a static Poisson's ratio.

[0102] Young's modulus is a physical quantity that characterizes the ability of rock to undergo pre-peak elastic deformation. In the elastic stage, the static Young's modulus is expressed as the ratio of axial stress to axial strain, and is calculated using the following formula:

[0103]

[0104] In the formula, E s is the static Young's modulus, GPa; Δσ is the axial stress change; Δε 1 is the axial strain change.

[0105] Poisson's ratio characterizes the compressibility of the material and describes the radial strain change Δε during elastic deformation. 2 and the corresponding axial strain change Δε 1 The static Poisson's ratio is calculated using the following formula:

[0106]

[0107] Step 103: Using the dynamic and static parameters obtained by the conventional method, a dynamic and static Young's modulus and Poisson's ratio conversion model of the study area is established, and its rationality is analyzed.

[0108] As an optional implementation, step 103 specifically includes:

[0109] According to the dynamic Young's modulus and dynamic Poisson's ratio of step 101, and the static Young's modulus and static Poisson's ratio of step 102, multiple fitting relationships of dynamic and static Young's modulus and dynamic and static Poisson's ratio are established respectively, and the dynamic and static Young's modulus conversion model and dynamic and static Poisson's ratio conversion model constructed under the conventional method are obtained.

[0110] For the six rock samples from Well A in the study area, a dynamic and static Young's modulus conversion model was established based on the above implementation method, as follows: Figure 3 As shown, the specific conversion relationship is as follows:

[0111] E s =1.9668E d -16.379, R 2 =0.8707 (13)

[0112] In the formula, E s and E d are the static Young's modulus and the dynamic Young's modulus, respectively.

[0113] Establish a dynamic and static Poisson's ratio conversion model, such as Figure 4 As shown, the specific conversion relationship is as follows:

[0114] μ s =0.5743μ d +0.0616, R 2 =0.7127 (14)

[0115] In the formula, μ s is the static Poisson's ratio, μ d is the dynamic Poisson's ratio.

[0116] According to the dynamic-static conversion model, the study found that the dynamic-static Young's modulus conversion relationship has a good correlation, indicating that the dynamic Young's modulus data obtained under ultrasonic testing conditions can be effectively converted into the Young's modulus value under static loading conditions. However, the correlation of the dynamic-static Poisson's ratio conversion relationship did not reach the expected goal, indicating that the performance of the Poisson's ratio parameter under dynamic testing and static loading conditions is different, which requires further research and exploration.

[0117] The study found that the reasons for the poor correlation between the dynamic and static Poisson's ratio conversion relationship include: the core scale of the mechanical experiment does not match the reservoir scale of the acoustic wave test; the core environment for indoor experiments is different from the actual formation environment; the rock is heterogeneous, and the collection of a small amount of rock samples for experiments leads to increased randomness, which in turn causes deviations in the experimental results.

[0118] Example 2.

[0119] Based on the problems existing in the above-mentioned dynamic-static conversion model and the heterogeneity of rocks, this application divides the rock sample selected in Example 1 into n homogeneous thin rock sub-samples, each layer of which has the same thickness and is considered to be homogeneous. According to the physical relationship between the mechanical parameters of each sub-sample and the mechanical parameters of the macroscopic rock sample, a physical model of rock mechanics parameters is constructed, and a method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core is proposed.

[0120] For heterogeneous rocks, let the rock sample height be L, the cross-sectional area be S, and the rock be evenly divided into n layers of sub-samples. Each layer of sub-sample is considered to be uniform, and the Young model of each layer of sub-sample is E 1 、E 2 、E 3 ,...,E n , the specific physical model is as follows Figure 5 shown.

[0121] Assume that under the action of load F, the total deformation of the rock mass is Δx, and the total deformation of the rock layer (subsample) I is Δx 1 , the total deformation of rock layer (subsample) II is Δx 2 , ..., the total deformation of rock layer (subsample) n is Δx n . Then the following formula exists:

[0122]

[0123] The total Young's modulus E of rock is:

[0124]

[0125] The relationship between the total Young's modulus of the rock sample and the Young's modulus of each subsample is:

[0126]

[0127] Assume that when the ultrasonic wave passes through heterogeneous rock, the average velocity of the rock mass is V, such as Figure 6 As shown, the velocity of rock layer (subsample) I is V 1 , the velocity of rock layer (subsample) II is V 2 , ..., the velocity of rock layer (subsample) n is V n . Then the following formula exists:

[0128]

[0129] The relationship between the total velocity of the rock sample and the velocity of each sub-sample, that is, the physical model of wave velocity, is:

[0130]

[0131] The relationship between the volume density of the rock sample and the volume density of each sub-sample, that is, the physical model of the volume density is:

[0132]

[0133] The Young's modulus of each layer of sub-sample is:

[0134]

[0135] The physical model of rock static Young's modulus is:

[0136]

[0137] The physical model of rock dynamic Young's modulus is:

[0138]

[0139] The above dynamic Young's modulus and static Young's modulus are linearly fitted based on the least square method to obtain the dynamic-static conversion model of Young's modulus.

[0140] Axial compression causes lateral strain and stress in rock samples. The lateral stress of each layer is not equal. Assume that the lateral stress of the i-th layer is σ si , the total lateral stress is σ s , the Young's modulus generated by the lateral deformation stress is E' i ,like Figure 7 shown.

[0141] Lateral stress σ per layer (sub-sample) si The total lateral stress σ of the entire rock sample s The relationship is:

[0142] σ s1 +σ s2 +…+σ si +…+σ sn =nσ s (26)

[0143] The lateral Young's stress-strain relationship of each layer (sub-sample) is:

[0144] σ si =E i ε 2i (27)

[0145] The overall lateral Young's stress-strain relationship is:

[0146] σ s =E i ε 2 (28)

[0147] The lateral stress-strain relationship between the subsample and the rock sample is:

[0148]

[0149] The axial stress-strain relationship between the sub-sample and the rock sample is:

[0150] E 1 ′ε 11 =E 2 ′ε 12 =…=E i ′ε 1i =… = nE′ε 1 (30)

[0151] The relationship between the Poisson's ratio of the rock sample and the Poisson's ratio of each subsample is:

[0152]

[0153] Assuming that the sub-sample is an isotropic medium, the transverse Young's modulus is equal to the longitudinal Young's modulus, that is,

[0154]

[0155] The physical model of the static Poisson's ratio of rock is:

[0156]

[0157] The physical model of rock dynamic Poisson's ratio is:

[0158]

[0159] The above dynamic Poisson's ratio and static Poisson's ratio are linearly fitted based on the least squares method to obtain a Poisson's ratio dynamic-static conversion model.

[0160] The static Young's modulus and static Poisson's ratio obtained by inversion using the method of the present application are different from those obtained by inversion using conventional methods. Figure 8 and Fig. 9 As shown, the static Young's modulus and static Poisson's ratio inverted using the method of the present application are more accurate.

[0161] The calculation of the rock mechanics parameter model proposed in this example is based on MATLAB software programming, including:

[0162] Each core is divided into 10,000 layers, and the wave velocity and volume density of each layer (subsample) are randomly generated. The distribution function satisfies the normal distribution, and its standard deviation and expected value are determined by the experimental values ​​of the wave velocity and volume density of the group of rock samples.

[0163] For the physical model of volume density, the randomly generated volume density of each layer (sub-sample) of rock samples must satisfy the normal distribution. The difference between the maximum density and the minimum density of each group of rock samples is selected as the standard deviation of the volume density normal distribution function, and the expected value is the experimental value of the indoor test of the rock sample.

[0164] For the physical model of the wave velocity, the randomly generated longitudinal wave velocity and shear wave velocity of each layer (sub-sample) must satisfy the normal distribution. The difference between the reciprocal of the minimum longitudinal wave velocity and the reciprocal of the maximum longitudinal wave velocity of each group of rock samples is used as the standard deviation of the normal distribution function of the longitudinal wave velocity, and the expected value is the reciprocal of the longitudinal wave velocity value of the rock sample tested indoors; the difference between the reciprocal of the minimum shear wave velocity and the reciprocal of the maximum shear wave velocity of each group of rock samples is used as the standard deviation of the shear wave velocity normal distribution function, and the expected value is the reciprocal of the shear wave velocity value of the rock sample tested indoors.

[0165] In order to improve the accuracy of the dynamic-static conversion relationship, the program of the theoretical model can be iteratively run, and the value of the dense data point area can be taken as the target value, such as Fig.10 As shown, the dynamic and static relationship satisfies the linear relationship.

[0166] like Fig.11 and Fig.12 As shown, static mechanical parameters and dynamic mechanical parameters are calculated based on the rock mechanical parameter physical model, and a dynamic and static Young's modulus and dynamic and static Poisson's ratio conversion model of Well A in the above study area is constructed. Compared with the conversion model constructed by conventional methods, the new method proposed in this example has a better linear relationship.

[0167] The present application provides a method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core. First, for a group of rock samples, each rock sample is regarded as consisting of different homogeneous sub-samples. The wave velocity and volume density of each sub-sample satisfy the normal distribution, and its standard deviation and expected value are determined by the experimental values ​​of the wave velocity and volume density of the group of rock samples. Substitute the generated wave velocity and volume density values ​​of each sub-sample into the rock mechanics physical model, calculate the static Young's modulus and dynamic Young's modulus of the rock sample, and construct a dynamic-static conversion model; analyze the rock mechanical properties of the stratigraphic section according to the dynamic-static conversion model; the rock mechanics physical model is the theoretical relationship between the mechanical parameters of the rock sample and the mechanical parameters of each sub-sample. The dynamic-static conversion model is obtained by linear fitting of the dynamic mechanical parameters and the static mechanical parameters. In this application, a more accurate dynamic-static conversion model is established through theoretical analysis and experimental verification, which can help researchers obtain more accurate rock mechanics parameters and provide a reference for the fields of oil and gas exploration and rock engineering.

[0168] In an exemplary embodiment, a computer device is provided. The computer device may be a server or a terminal. The internal structure diagram thereof may be as follows: Fig.13As shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, referred to as I / O) and a communication interface. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store dynamic mechanical parameter data. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, a method for constructing a dynamic-static conversion model of rock mechanics of a non-destructive core is realized.

[0169] Those skilled in the art will understand that Fig.13 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components. In an exemplary embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the above-mentioned method for constructing a rock mechanics dynamic-static conversion model of a non-destructive core is implemented.

[0170] In an exemplary embodiment, a computer-readable storage medium is provided, storing a computer program, which, when executed by a processor, implements the above-mentioned method for constructing a dynamic-static conversion model of rock mechanics for non-destructive cores.

[0171] In an exemplary embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the above-mentioned method for constructing a dynamic-static conversion model of rock mechanics of a non-destructive core.

[0172] Those of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM may be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0173] The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. The non-relational database may include a distributed database based on blockchain, etc., but is not limited thereto. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but is not limited thereto.

[0174] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0175] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A method for constructing a dynamic-static conversion model of rock mechanics for non-destructive cores, characterized in that: include: Based on ultrasonic waves, a group of static mechanical parameters and dynamic mechanical parameters of rock samples are obtained; the static mechanical parameters include static Young's modulus and static Poisson's ratio; The dynamic mechanical parameters include dynamic Young's modulus and dynamic Poisson's ratio; static mechanical parameters and dynamic mechanical parameters are determined by using a rock mechanical parameter physical model; the rock mechanical parameter physical model is a theoretical relationship between the mechanical parameters of a rock sample and the mechanical parameters of each sub-sample; the sub-samples are obtained by evenly dividing the physical model of the rock sample; the rock mechanical parameter physical model includes a physical model of a dynamic Young's modulus, a physical model of a static Young's modulus, a physical model of a dynamic Poisson's ratio and a physical model of a static Poisson's ratio; According to the static mechanical parameters and dynamic mechanical parameters of a group of rock samples, a rock mechanics dynamic-static conversion model is constructed; the rock mechanics dynamic-static conversion model includes a Young's modulus dynamic-static conversion model and a Poisson's ratio dynamic-static conversion model; the Young's modulus dynamic-static conversion model is obtained by linearly fitting the dynamic Young's modulus calculated based on a physical model of the dynamic Young's modulus and the static Young's modulus calculated based on a physical model of the static Young's modulus; the Poisson's ratio dynamic-static conversion model is obtained by linearly fitting the dynamic Poisson's ratio calculated based on a physical model of the dynamic Poisson's ratio and the static Poisson's ratio calculated based on a physical model of the static Poisson's ratio; The dynamic mechanical parameters of the single well section obtained in the logging process are obtained, and the static mechanical parameters of the formation section are determined using the rock mechanics dynamic-static conversion model to perform rock mechanical property analysis of the formation section.

2. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 1, characterized in that: Based on ultrasound, a set of static and dynamic mechanical parameters of rock samples are obtained, including: Obtain a group of rock samples, divide the rock samples into n rock sub-samples, and obtain the volume density of the rock sub-samples; each rock sub-sample has the same thickness; determining the shear wave velocity and the longitudinal wave velocity of the ultrasonic wave penetrating each layer of the rock subsample; According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic mechanical parameters and static mechanical parameters of the rock sample are determined using a rock mechanical parameter physical model; the mechanical parameters include Young's modulus and Poisson's ratio.

3. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 2, characterized in that: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the static mechanical parameters and dynamic mechanical parameters of the rock sample are determined by using the rock mechanical parameter physical model, specifically including: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic Young's modulus and the static Young's modulus of the rock sample are determined by using the physical model of the dynamic Young's modulus and the physical model of the static Young's modulus; According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample, the dynamic Poisson's ratio and the static Poisson's ratio of the rock sample are determined by using the physical model of the dynamic Poisson's ratio and the physical model of the static Poisson's ratio.

4. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 3, characterized in that: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample and the volume density of the rock sub-sample, the dynamic Young's modulus and the static Young's modulus of the rock sample are determined by using the physical model of the dynamic Young's modulus and the physical model of the static Young's modulus, specifically including: Physical Model Using Dynamic Young's Modulus determining a dynamic Young's modulus of the rock sample; Physical Model Using Static Young's Modulus determining a static Young's modulus of the rock sample; Among them, E d is the dynamic Young's modulus of the rock sample; E s is the static Young's modulus of the rock sample; E i is the Young's modulus of the rock subsample in the i-th layer. i is the volume density of the rock subsample in the i-th layer; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

5. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 3, characterized in that: According to the transverse wave velocity and longitudinal wave velocity of the ultrasonic wave penetrating the rock sub-sample, the dynamic Poisson's ratio and the static Poisson's ratio of the rock sample are determined by using the physical model of the dynamic Poisson's ratio and the physical model of the static Poisson's ratio, specifically including: Physical Model Using Dynamic Poisson's Ratio determining a dynamic Poisson's ratio of the rock sample; Physical Model Using Static Poisson's Ratio determining a static Poisson's ratio of the rock sample; Among them, μ d is the dynamic Poisson's ratio of the rock sample; μ s is the static Poisson's ratio of the rock sample; V pi is the longitudinal wave velocity of the rock subsample in the i-th layer; V si is the shear wave velocity of the i-th rock subsample; n is the total number of rock subsample layers.

6. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 1, characterized in that: The dynamic-static conversion model of Young's modulus is: E s '=a1·E d '+b1; Among them, E d ' is the dynamic Young's modulus of the single well profile obtained during the logging process; E s ' is the static Young's modulus of the formation section; a1 is the first proportional coefficient; b1 is the first constant term.

7. The method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to claim 1, characterized in that: The Poisson's ratio dynamic-static conversion model is: μ s '=a2·μ d '+b2; where μ d ' is the dynamic Poisson's ratio of the single well profile obtained during the logging process; μ s ' is the static Poisson's ratio of the stratigraphic section; a2 is the second proportional coefficient; b2 is the second constant term.

8. A computer device comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core as described in any one of claims 1-7.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to any one of claims 1 to 7 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method for constructing a dynamic-static conversion model of rock mechanics for a non-destructive core according to any one of claims 1 to 7 is implemented.

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