A shear wave time difference correction method and system for eliminating the influence of shale lamination angle anisotropy

Abstract

The present invention discloses a shear wave time difference correction method and system for eliminating the influence of shale laminar angle anisotropy. It relates to the field of geophysical well logging technology. It includes: acquiring well logging data of horizontal wells; fitting the well logging data and calculating the shear wave anisotropy coefficients at different depths; correcting the well logging data according to the shear wave anisotropy coefficients to obtain the corrected shear wave time difference. The present invention eliminates the influence of shear wave logging anisotropy of laminar shale, gets rid of the dependence on rock physics experiments, and saves the cost of implementing the scheme.

Description

Technical Field

[0001] The present invention relates to the field of geophysical well logging technology, and more particularly to a shear wave time difference correction method and system for eliminating the influence of shale lamination angle anisotropy. Background Art

[0002] As unconventional oil and gas has become a key area of ​​oil and gas exploration and development in my country, the exploration and development of shale oil and gas has increased. However, shale has strong anisotropy, which increases the difficulty of shale oil and gas exploration and development. At present, shale reservoirs are mainly developed by horizontal wells. The anisotropy caused by the development of shale laminations and fractures has a serious impact. Anisotropy refers to the different results of some physical parameters inside the rock in different directions, such as acoustic time difference, permeability, and resistivity. Acoustic time difference is a very important parameter in well logging interpretation and evaluation. It can be used to interpret and evaluate the lithology of the well wall rock, identify the reservoir, and estimate the porosity of the reservoir. However, there is a large difference between the acoustic time difference measurement value in the horizontal well and the measurement value in the vertical well, resulting in the data used in the well logging interpretation and evaluation cannot truly reflect the acoustic time difference value of the reservoir, affecting the accuracy of the reservoir evaluation. Therefore, it is of great significance to perform acoustic time difference anisotropy correction on the horizontal well shale formation.

[0003] At present, the commonly used method for correcting acoustic anisotropy of shale formations in horizontal wells is the acoustic anisotropy correction method based on rock physics experiments proposed by Xiong Jian. This method collects core samples with different lamination angles, processes their images with grayscale, and statistically calculates the lamination angle from them. Combined with the acoustic time difference data measured in the experiment, the relationship between the acoustic correction coefficient of the shale core and the lamination angle is established, and this is used to correct the acoustic anisotropy of shale formations in horizontal wells. However, due to the large number of cores consumed, the cost of coring samples downhole is high, and it is difficult to obtain the lamination angle.

[0004] Therefore, how to provide a shear wave time difference correction method and system to eliminate the influence of shale lamination angle anisotropy, eliminate the influence of laminar shale shear wave logging anisotropy while getting rid of the dependence on rock physics experiments and saving the cost of implementing the scheme is an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0005] In view of this, the present invention provides a shear wave time difference correction method and system for eliminating the influence of shale lamination angle anisotropy, eliminating the influence of laminar shale shear wave logging anisotropy, getting rid of the dependence on rock physics experiments, and saving the cost of program implementation.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: a shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy, comprising:

[0007] Obtain logging data for horizontal wells;

[0008] Fitting the logging data and calculating the shear wave anisotropy coefficients at different depths;

[0009] The logging data is corrected according to the shear wave anisotropy coefficient to obtain a corrected shear wave time difference.

[0010] Preferably, the logging data includes lamination angle data and shear wave time difference data.

[0011] Preferably, the method further comprises: constructing a shale model, simulating the relationship between laminar angle data and shear wave time difference data, and the relationship between laminar angle cosine and shear wave anisotropy coefficient.

[0012] Preferably, the shale model is formed by periodic superposition of laminae and mud layers and is a transversely isotropic medium;

[0013] The stiffness coefficient expression in the constitutive relationship of the shale model is as follows:

[0014]

[0015] Among them, the shear modulus of the lamina is μ1, the Lame coefficient is λ1, and the bulk density is ρ1; the shear modulus of the mud is μ2, the Lame coefficient is λ2, and the bulk density is ρ2; the lamina thickness is d, and the lamina density is m.

[0016] Preferably, the relationship between the simulated laminar angle data and the shear wave time difference data and the relationship between the laminar angle cosine and the shear wave anisotropy coefficient include:

[0017] In a transversely isotropic medium, the constitutive equation and geometric equation are substituted into the motion equation, and the elastic wave equation of the transversely isotropic medium is obtained through matrix calculation:

[0018]

[0019] Given an arbitrary plane wave wave function, substitute the wave function into the elastic wave equation and express it in matrix form:

[0020]

[0021] Among them, ρ = md(ρ1-ρ2) + ρ2, ρ is the volume density of the shale model, θ is the angle between the sound wave propagation direction and the lamination; u x 、u y 、u z are the displacements in the x, y, and z directions respectively; V is the speed of sound wave propagation, and t is the propagation time;

[0022] Solving the matrix, we get the shear wave velocity:

[0023]

[0024] Where V represents the shear wave velocity;

[0025] The shear wave velocity is converted into a shear wave time difference:

[0026]

[0027] In the formula, DTS represents the shear wave time difference, V represents the shear wave velocity, and δ represents the shear wave parameter;

[0028] The ratio method anisotropy coefficient is used to characterize the shear wave anisotropy coefficient at different lamination angles, and the following is obtained:

[0029]

[0030] Where y is the shear wave anisotropy coefficient, DTS θ Denotes the shear wave time difference when the angle is θ, DTS 90 is the shear wave time difference when the laminar angle is 90°.

[0031] Preferably, fitting the logging data and calculating the shear wave anisotropy coefficients at different depths includes:

[0032] The well logging data is fitted to obtain the following formula:

[0033]

[0034] When the lamination angle is 90°, x=cos90°=0,

[0035] When the lamination angle is 0°, x=cos0°=1,

[0036] The calculated shear wave anisotropy coefficient is expressed as:

[0037]

[0038] Where y represents the shear wave anisotropy coefficient, DTS θ represents the shear wave time difference when the angle is θ, cosθ represents the cosine value of the lamination angle, and c represents the attenuation coefficient, which is obtained by fitting the actual logging data.

[0039] Preferably, the corrected shear wave time difference is expressed as:

[0040] DTS J =DTS÷y;

[0041] Among them, DTS Jis the shear wave time difference after correction, DTS is the shear wave time difference before correction, and y is the shear wave anisotropy coefficient.

[0042] Preferably, a shear wave time difference correction system for eliminating the influence of shale lamination angle anisotropy comprises:

[0043] A logging data acquisition module, used to acquire logging data of horizontal wells;

[0044] A fitting calculation module, used for fitting the logging data and calculating the shear wave anisotropy coefficient at different depths;

[0045] The shear wave time difference correction module is used to correct the logging data according to the shear wave anisotropy coefficient to obtain the corrected shear wave time difference.

[0046] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a shear wave time difference correction method and system for eliminating the influence of shale lamination angle anisotropy, including: obtaining logging data of horizontal wells; fitting the logging data and calculating the shear wave anisotropy coefficient at different depths; correcting the logging data according to the shear wave anisotropy coefficient to obtain the corrected shear wave time difference. The present invention aims at the problem that the commonly used correction method currently needs to carry out rock physics experiments, which is costly and has errors. It eliminates the influence of shear wave logging anisotropy of laminar shale, gets rid of the dependence on rock physics experiments, and saves the cost of implementing the solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0048] Figure 1 This is a relationship diagram between the lamination angle and the shear wave time difference provided in Example 1 of the present invention.

[0049] Figure 2 This is a relationship diagram between the cosine value of the lamination angle and the shear wave anisotropy coefficient provided in Example 1 of the present invention.

[0050] Figure 3 A schematic diagram of the fitting results of the horizontal well target layer data provided in Example 2 of the present invention.

[0051] Figure 4 This is a schematic diagram of the comparison results before and after the horizontal well shear wave time difference correction provided in Example 2 of the present invention.

[0052] Figure 5This is a histogram of the shear wave time difference frequency distribution of the target layer before the horizontal well correction and after the vertical well and horizontal well correction provided in Example 2 of the present invention.

[0053] Figure 6 The normal distribution curve diagram of the shear wave time difference frequency distribution of the target layer before the horizontal well correction and after the vertical well and horizontal well correction provided in Example 2 of the present invention.

[0054] Figure 7 A schematic flow chart of a shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy provided in an embodiment of the present invention.

[0055] Figure 8 A schematic diagram of the structure of a shear wave time difference correction system for eliminating the influence of shale lamination angle anisotropy provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0056] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0057] The embodiment of the present invention discloses a shear wave time difference correction method and system for eliminating the influence of angular anisotropy of shale laminae. The method aims to eliminate the influence of anisotropy of shear wave logging in laminar shale, get rid of the dependence on rock physics experiments, and save the cost of implementing the solution, as the currently commonly used correction method requires supporting rock physics experiments, which is costly and has errors.

[0058] Example 1

[0059] Embodiment 1 of the present invention discloses a shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy, such as Figure 7 As shown, it includes: acquiring logging data of a horizontal well; fitting the logging data and calculating the shear wave anisotropy coefficient at different depths; correcting the logging data according to the shear wave anisotropy coefficient to obtain the corrected shear wave time difference.

[0060] Specifically, the logging data includes lamination angle data and shear wave time difference data.

[0061] Specifically, it also includes: constructing a shale model, simulating the relationship between laminar angle data and shear wave time difference data, and the relationship between laminar angle cosine and shear wave anisotropy coefficient.

[0062] Specifically, the shale model is formed by periodic superposition of laminae and mud layers and is a transversely isotropic medium;

[0063] Among them, stress-strain analysis is performed on the shale model, and positive stress f is applied to the laminae and mud layers in the directions parallel to the x-axis, y-axis and z-axis respectively. x1 、f x2 , f y1 、f y2 , f z1 、f z2 , considering the continuity of the mud layer and the laminae in the shale model, the strain magnitudes of the two media in the x-axis and y-axis directions should be consistent, and the stresses of the two media in the z-axis direction should be consistent. That is, the stress-strain relationship of the two media should be as follows:

[0064]

[0065] In the formula, ε xx1 represents the strain magnitude of the lamination in the x-axis direction, ε xx2 represents the strain of the mud layer in the x-axis direction, ε xx represents the strain magnitude in the x-axis direction, ε yy1 represents the strain magnitude of the laminae in the y-axis direction, ε yy2 represents the strain magnitude of the mud layer in the y-axis direction, ε yy represents the strain magnitude in the y-axis direction, f z1 Indicates the stress magnitude of the lamination in the z-axis direction, f z2 represents the stress magnitude of the mud layer in the z-axis direction, f z It represents the stress magnitude in the z-axis direction.

[0066] Because the shale layer and the laminae are both isotropic media, the stiffness coefficients of the shale layer and the laminae can be expressed by the Lame coefficient and the shear modulus. According to Hooke's law, the stress-strain relationship of the shale model can be expressed as:

[0067]

[0068] For the entire shale model, the stress f in the x-axis direction is x The stress f of the laminae and mud layers can be used x1 、f x2 To express the stress f in the y-axis direction y The stress f of the laminae and mud layers can be used y1 、f y2 To represent the strain ε in the z-axis direction zz The strain ε of the laminae and shale layers can be expressed as zz1 , ε zz2 To express, that is:

[0069]

[0070] Similarly, shear stress f is applied to the laminae and mud layers in parallel to the x-axis direction. yz1 、f yz2 , and apply shear stress f to the laminae and mud layers in parallel to the y-axis direction xz1 、f xz2 , and apply shear stress f to the laminae and mud layers in parallel to the z-axis direction xy1 、f xy2 The shear forces applied by the two media parallel to the x-axis and y-axis are equal, and the force parallel to the z-axis makes the shear strains of the two media equal but the shear forces unequal. Therefore, the relationship between the shear stress and shear strain of the entire shale model can be obtained, that is:

[0071]

[0072] Combining the above formulas, the constitutive relationship of the shale model can be obtained as follows:

[0073]

[0074] The stiffness coefficient expression in the constitutive relationship of the shale model is shown in formula (6):

[0075]

[0076] Among them, the shear modulus of the lamina is μ1, the Lame coefficient is λ1, and the bulk density is ρ1; the shear modulus of the mud layer is μ2, the Lame coefficient is λ2, and the bulk density is ρ2; the lamina thickness is d, and the lamina density is m.

[0077] Specifically, the relationship between the simulated laminar angle data and the shear wave time difference data and the relationship between the laminar angle cosine and the shear wave anisotropy coefficient include:

[0078] The relationship between the simulated laminar angle data and the shear wave time difference data and the relationship between the laminar angle cosine and the shear wave anisotropy coefficient include:

[0079] Define the geometric equations:

[0080]

[0081] Equations of motion:

[0082]

[0083] Among them, F x , F y , F z For physical strength.

[0084] In a transversely isotropic medium, the constitutive equation (5) and the geometric equation (7) are substituted into the motion equation (8), and the body force term in the motion equation is ignored. The elastic wave equation of the transversely isotropic medium is obtained by matrix calculation. Since the elastic mechanical properties of the transversely isotropic medium are symmetric about the symmetry axis (z axis) of the medium, that is, all the terms derived with respect to y in the wave equation are 0, the wave equation can be simplified to the following form:

[0085]

[0086] Given an arbitrary plane wave wave function:

[0087]

[0088] In the formula, u x 、u y 、u z are the displacements in the x, y and z directions respectively; u0, v0 and w0 are the initial displacements in the x, y and z directions respectively; θ is the angle between the sound wave propagation direction and the lamination; V is the sound wave propagation velocity and t is the propagation time.

[0089] Substitute the wave function of the plane wave into the elastic wave equation and express it in matrix form:

[0090]

[0091] Among them, ρ = md(ρ1-ρ2) + ρ2, ρ is the volume density of the shale model, θ is the angle between the sound wave propagation direction and the lamination, that is, the lamination angle;

[0092] To solve the matrix, we need to make the determinant of the matrix on the left equal to 0. For the convenience of expression, we can use formula (12):

[0093]

[0094] Further, the shear wave velocity V is obtained:

[0095]

[0096] The simulated shear wave velocity is converted into shear wave time difference for study.

[0097] Specifically, the shear wave velocity is converted into a shear wave time difference:

[0098]

[0099] Where DTS is the shear wave time difference, in μs / ft; V is the shear wave velocity, in km / s; δ is the shear wave parameter;

[0100] Specifically, according to 1ft=0.0003048km, in the embodiment of the present invention, as shown in formula (15):

[0101]

[0102] The shear wave parameter δ is obtained as 304.8.

[0103] The embodiment of the present invention adopts the ratio method anisotropy coefficient to characterize the shear wave anisotropy coefficient at different laminae angles, that is, the shear wave time difference value at other laminae angles is divided by the shear wave time difference value when the laminae angle is 90°, as shown in formula (16), and the result is:

[0104]

[0105] Where y is the shear wave anisotropy coefficient, DTS θ Denotes the shear wave time difference when the angle is θ, DTS 90 is the shear wave time difference when the laminar angle is 90°.

[0106] The above method is used to simulate the relationship between the laminar angle data and the shear wave time difference data, as well as the relationship between the laminar angle cosine and the shear wave anisotropy coefficient. Figure 1 The figure shows the relationship between the lamination angle (the complementary angle of the well inclination angle) and the shear wave time difference. Figure 2 This is the relationship between the cosine value of the lamination angle and the shear wave anisotropy coefficient.

[0107] Specifically, fitting the logging data and calculating the shear wave anisotropy coefficients at different depths includes:

[0108] according to Figure 2 , the shear wave anisotropy coefficient and the cosine value of the laminae angle can be fitted using formula (17):

[0109]

[0110] When the lamination angle is 90°, x=cos90°=0,

[0111] When the lamination angle is 0°, x=cos0°=1,

[0112] The final calculated shear wave anisotropy coefficient is expressed as formula (18):

[0113]

[0114] Where y represents the shear wave anisotropy coefficient, DTS θrepresents the shear wave time difference when the angle is θ, cosθ represents the cosine value of the lamination angle, and c represents the attenuation coefficient, which is obtained by fitting the actual logging data.

[0115] However, in actual logging data, the shear wave time difference with laminar angles of 0° and 90° is not easy to obtain, so both sides of formula (18) are multiplied by DTS 90 , transformed into formula (19):

[0116] DTS θ =(DTS0-DTS 90 )cos c θ+DTS 90 ; (19)

[0117] Formula (19) can be used to obtain the parameter DTS by fitting the shear wave time difference at other laminae angles when the shear wave time difference at laminae angles of 0° and 90° is difficult to obtain. 90 , DTS0 and c are brought back to formula (18) to obtain the shear wave anisotropy coefficient y. The correction formula for the shear wave anisotropy of laminar shale is:

[0118] DTS J =DTS÷y; (20)

[0119] Among them, DTS J is the shear wave time difference after correction, DTS is the shear wave time difference before correction, and y is the shear wave anisotropy coefficient.

[0120] Embodiment 1 of the present invention can avoid the difficulty of obtaining parameters during the correction process and relying on rock physics experimental data for calibration. It is easy to operate and saves the cost of coring downhole samples and conducting rock physics experiments.

[0121] Example 2

[0122] Embodiment 2 of the present invention discloses a shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy, comprising:

[0123] Taking a shale gas well in a certain basin as an example, the implementation steps and effects of the embodiment of the present invention are demonstrated. The specific steps are as follows:

[0124] Step 1: Read some discrete well inclination data and shear wave time difference data in the horizontal well according to the measured curve. Table 1 shows some discrete well inclination data and corresponding shear wave time difference logging response values ​​read in the target layer section in the horizontal well.

[0125] Table 1

[0126]

[0127] Step 2: Based on the selected data, use formula (19) to fit the data in Table 1 to determine the model parameters. The fitting results are as follows: Figure 3 As shown, according to the fitting results, c = 3.48, DTS 90 =144.73μs / ft, DTS0 = 144.73-37.07 = 107.66μs / ft, fitting correlation coefficient R 2 =0.9979.

[0128] Step 3: Calculate the shear wave anisotropy coefficient at different depths, and bring the parameters fitted in step 2 back into formula (18) to obtain:

[0129]

[0130] Step 4: Correct the shear wave time difference logging data of the horizontal well according to formula (20) and formula (21). The correction result is as follows: Figure 4 As shown in the figure, the corrected curve retains the undulating characteristics of the curve before correction. As the well inclination angle increases, the correction amount of the correction curve increases accordingly. Select the main target layer, make the frequency distribution histogram and normal distribution curve of its shear wave time difference before and after correction in the pilot well and horizontal well, and compare them, as shown in the figure. Figure 5 As shown in the figure, no filling, cross grid filling and oblique line filling represent the target layer shear wave time difference frequency distribution histogram before horizontal well correction, vertical well and horizontal well correction, respectively. Figure 6 As shown, the normal distribution curves of the shear wave time difference frequency distribution of the target layer before horizontal well correction, vertical well and horizontal well correction are respectively shown. It can be found that the peak areas of the normal distribution curves of the shear wave time difference of the target layer after vertical well and horizontal well correction coincide, indicating that the correction effect is good.

[0131] Example 3

[0132] Embodiment 3 of the present invention discloses a shear wave time difference correction system for eliminating the influence of shale lamination angle anisotropy, such as Figure 8 As shown, including:

[0133] A logging data acquisition module, used to acquire logging data of horizontal wells;

[0134] A fitting calculation module, used for fitting the logging data and calculating the shear wave anisotropy coefficient at different depths;

[0135] The shear wave time difference correction module is used to correct the logging data according to the shear wave anisotropy coefficient to obtain the corrected shear wave time difference.

[0136] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0137] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy, characterized in that: include: Obtain logging data for horizontal wells; Fitting the logging data and calculating the shear wave anisotropy coefficients at different depths; Correcting the logging data according to the shear wave anisotropy coefficient to obtain a corrected shear wave time difference; The logging data is fitted and the shear wave anisotropy coefficients at different depths are calculated, including: The well logging data is fitted to obtain the following formula: When the lamination angle is 90°, x=cos90°=0, When the lamination angle is 0°, x=cos0°=1, The calculated shear wave anisotropy coefficient is expressed as: Where y represents the shear wave anisotropy coefficient, DTS θ represents the shear wave time difference when the laminar angle is θ, cosθ represents the cosine value of the laminar angle, and c represents the attenuation coefficient; DTS 90 It represents the shear wave time difference when the laminae angle is 90 degrees; DTS0 represents the shear wave time difference when the laminae angle is 0 degrees.

2. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy according to claim 1, characterized in that: The logging data includes lamination angle data and shear wave time difference data.

3. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy according to claim 1, characterized in that: Also includes: A shale model was constructed to simulate the relationship between the laminae angle data and the shear wave time difference data, as well as the relationship between the laminae angle cosine and the shear wave anisotropy coefficient.

4. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy according to claim 3, characterized in that: The shale model is formed by periodic superposition of laminae and mud layers and is a transversely isotropic medium; The stiffness coefficient expression in the constitutive relationship of the shale model is as follows: c 66 =mdμ1+(1-md)μ2 Among them, the shear modulus of the lamina is μ1, the Lame coefficient is λ1, and the bulk density is ρ1; the shear modulus of the mud is μ2, the Lame coefficient is λ2, and the bulk density is ρ2; the lamina thickness is d, and the lamina density is m.

5. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy according to claim 3, characterized in that: The relationship between the simulated laminar angle data and the shear wave time difference data and the relationship between the laminar angle cosine and the shear wave anisotropy coefficient include: In a transversely isotropic medium, the constitutive equation and geometric equation are substituted into the motion equation, and the elastic wave equation of the transversely isotropic medium is obtained through matrix calculation: Given an arbitrary plane wave wave function, substitute the wave function into the elastic wave equation and express it in matrix form: Among them, ρ = md(ρ1-ρ2) + ρ2, ρ is the volume density of the shale model, θ is the angle between the sound wave propagation direction and the lamination, u x 、u y 、u z are the displacements in the x, y, and z directions respectively; V is the acoustic wave propagation velocity, t is the propagation time; ρ1 is the volume density of the laminae, ρ2 is the volume density of the mud layer; u0, v0, w0 are the initial displacements in the x, y, and z directions respectively; Solving the matrix, we get the shear wave velocity: Where V represents the shear wave velocity; The shear wave velocity is converted into a shear wave time difference: In the formula, DTS represents the shear wave time difference, V represents the shear wave velocity, and δ represents the shear wave parameter; The ratio method anisotropy coefficient is used to characterize the shear wave anisotropy coefficient at different lamination angles, and the following is obtained: Where y is the shear wave anisotropy coefficient, DTS θ The shear wave time difference when the laminar angle is θ, DTS 90 is the shear wave time difference when the laminar angle is 90°.

6. A shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy according to claim 1, characterized in that: The corrected shear wave time difference is expressed as: DTS J =DTS÷y; Among them, DTS J is the shear wave time difference after correction, DTS is the shear wave time difference before correction, and y is the shear wave anisotropy coefficient.

7. A shear wave time difference correction system for eliminating the influence of shale lamination angle anisotropy, applied to a shear wave time difference correction method for eliminating the influence of shale lamination angle anisotropy as claimed in any one of claims 1 to 6, characterized in that: include: A logging data acquisition module, used to acquire logging data of horizontal wells; A fitting calculation module, used for fitting the logging data and calculating the shear wave anisotropy coefficient at different depths; The shear wave time difference correction module is used to correct the logging data according to the shear wave anisotropy coefficient to obtain the corrected shear wave time difference.

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