A method and device for modeling velocity anisotropy of shallow surface media

Abstract

The present application provides a method and device for modeling the velocity anisotropy of shallow surface media, which belongs to the field of petroleum exploration technology. The anisotropic parameter involved in the present invention is a horizontally symmetric axis transversely isotropic medium, which can be divided into two categories. One is that the velocity of the symmetry axis is a horizontal fast speed, that is, the vertical velocity is the same as the horizontal slow speed; the other is that the velocity of the symmetry axis is a horizontal slow speed, and the vertical velocity is the same as the horizontal fast speed; first, by comparing the micro-logging initial arrival data with the horizontal fast speed azimuth initial arrival data and the horizontal slow speed azimuth initial arrival data, it is determined which category the anisotropic parameter belongs to, and based on the symmetry axis velocity and the vertical velocity, the anisotropic parameter is determined; and an anisotropic model is constructed based on the anisotropic parameter. The use of the shallow surface medium velocity anisotropy modeling method provided by the present application solves the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of the existing surface model when there is strong anisotropy in the surface layer.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of petroleum exploration technology, and in particular to a method and device for modeling velocity anisotropy of shallow surface media. Background Art

[0002] Seismic exploration is the primary method for finding and exploring for oil and natural gas. Basic seismic theory assumes that the excitation point and the receiving point are on the same horizontal plane and that the seismic wave velocity in the formation is uniform. However, the actual surface elevation is undulating, and a set of weathered layers or unconsolidated sediments called low-velocity zones (layers) are commonly found near the surface. Due to the varying degrees of weathering or consolidation at different locations, the thickness and velocity of the low-velocity zones vary significantly laterally relative to the underlying strata. Lateral variations in the low-velocity zones distort the hyperbolic shape of the travel time of seismic exploration reflection waves, affecting the accuracy of seismic imaging. Therefore, the distortion caused by the near-surface low-velocity zones on the travel time of reflection waves must be eliminated during seismic data processing.

[0003] In the existing technology, the velocity and thickness of the low-deceleration zone are directly used as the near-surface velocity model, and then fused with the shallow, medium and deep velocity models as the velocity model for depth domain imaging to perform depth domain migration imaging. This is called near-surface velocity modeling or surface velocity modeling for depth domain imaging of seismic data. However, this method establishes a surface model based on an isotropic medium (that is, the medium velocity is independent of direction). When there is strong anisotropy in the surface layer, it will cause the shallow imaging effect to deteriorate or even no imaging, the deep imaging frequency to decrease, and the imaging depth to be inaccurate. Therefore, when there is strong anisotropy in the surface layer, the existing surface model has poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth, which are problems that need to be solved urgently. Summary of the Invention

[0004] The embodiments of the present application provide a method and device for modeling the velocity anisotropy of shallow surface media, aiming to solve the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of existing surface models when there is strong anisotropy in the surface layer.

[0005] A first aspect of an embodiment of the present application provides a method for modeling velocity anisotropy of a shallow surface medium, which is applied to a transversely isotropic medium with a horizontal symmetry axis, comprising:

[0006] Acquire the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction;

[0007] The first arrival data is the first arrival data of the production shot when simulating the surface structure obtained by micro-logging, and the second and third arrival data are the first arrival data obtained in actual production.

[0008] In the second and third initial arrival data, the velocity corresponding to the initial arrival data whose difference from the first initial arrival data is less than a preset difference is determined as the vertical velocity, and the velocity corresponding to the other initial arrival data is determined as the symmetry axis velocity; that is, if the vertical velocity is determined to be a slow horizontal velocity, then the symmetry axis velocity is a fast horizontal velocity, or if the vertical velocity is determined to be a fast horizontal velocity, then the symmetry axis velocity is a slow horizontal velocity;

[0009] Determine anisotropy parameters based on the symmetry axis velocity and vertical velocity;

[0010] Anisotropic models are constructed based on anisotropic parameters.

[0011] Optionally, in the second initial arrival data and the third initial arrival data, determining a velocity corresponding to the initial arrival data having a difference with the first initial arrival data smaller than a preset difference as the vertical velocity, and determining a velocity corresponding to the other initial arrival data as the symmetry axis velocity includes:

[0012] Based on the fitting of the common center point first arrival ellipse at the micro-logging point, the second first arrival data and the first first arrival data are extracted according to the fast and slow azimuth of the fitting, and compared with the first first arrival data, the vertical velocity corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, the preliminary value of the symmetry axis velocity corresponding to the other first arrival data, and the azimuth angle are obtained;

[0013] Based on 2D forward modeling and tomographic inversion with different anisotropies, the correction coefficients for the preliminary values ​​of the symmetry axis velocity are determined;

[0014] The preliminary value of the symmetry axis velocity is corrected based on the correction coefficient to obtain the symmetry axis velocity.

[0015] Optionally, obtaining first initial arrival data of a concentric point of the micro-logging, second initial arrival data generated in a horizontal fast speed direction, and third initial arrival data generated in a horizontal slow speed direction includes:

[0016] Obtaining isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data at least includes the thickness of the i-th layer, the velocity of the i-th layer, and the velocity of the last layer in the micro-logging surface structure;

[0017] By fitting the first arrivals of the concentric points, the horizontal fast speed azimuth and horizontal slow speed azimuth of the anisotropic medium are calculated. The horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed.

[0018] Based on the horizontal fast speed azimuth and the horizontal slow speed azimuth, second first arrival data and third first arrival data are extracted from the first arrival data obtained in actual production.

[0019] Optionally, the horizontal fast velocity azimuth and the horizontal slow velocity azimuth of the anisotropic medium are calculated by fitting the first arrivals of the concentric points, including:

[0020] Rearrange the space according to the direction of the gun inspection when the initial arrival is made, forming an elliptical space diagram;

[0021] Fit the ellipse space diagram according to the ellipse formula and calculate the ellipse inclination;

[0022] Based on the elliptical inclination angle, the horizontal fast speed azimuth and the horizontal slow speed azimuth are determined.

[0023] Optionally, based on fitting the common center point first arrival ellipse at the micro-logging point, extracting the second first arrival data and the first first arrival data according to the fast and slow azimuths of the fitting, and comparing them with the first first arrival data, obtaining the vertical velocity, preliminary value of the symmetry axis velocity, and azimuth angle corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, including:

[0024] Determine the azimuths of all shot pairs, divide the first arrival data into multiple groups according to the azimuths, and perform tomographic inversion on each of the multiple groups of first arrival data to obtain multiple groups of velocity volume data;

[0025] Perform spatial rearrangement on multiple sets of velocity volume data to form a velocity ellipse spatial map;

[0026] The velocity at each position is fitted according to the ellipse formula to obtain the vertical velocity, preliminary values ​​of the symmetry axis velocity and azimuth angle.

[0027] Optionally, based on two-dimensional forward modeling and tomographic inversion of different anisotropies, a correction coefficient for the preliminary value of the symmetry axis velocity is determined, including:

[0028] A vertical velocity model is established based on the surface structure investigated by micro-well logging, and multiple vertical velocity models are established using multiple anisotropic parameters.

[0029] Based on the forward modeling data of multiple vertical velocity models, tomographic inversion is performed to obtain the velocity of each vertical velocity model;

[0030] Based on the velocity of each vertical velocity model, a correction factor for the preliminary value of the symmetry axis velocity is determined.

[0031] A second aspect of the present application provides a shallow surface medium velocity anisotropy modeling device, comprising:

[0032] Acquisition module: used to obtain the first initial arrival data of the concentric point of micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction. Among them, the first initial arrival data is the initial arrival data of the production shot when simulating the surface structure obtained by micro-logging, and the second and third initial arrival data are the initial arrival data obtained in actual production.

[0033] A first determination module is configured to determine, among the second and third initial arrival data, a velocity corresponding to an initial arrival data having a difference with the first initial arrival data that is less than a preset difference as a vertical velocity, and to determine a velocity corresponding to another initial arrival data as a symmetry axis velocity; that is, if the vertical velocity is determined to be a slow horizontal velocity, the symmetry axis velocity is a fast horizontal velocity, or if the vertical velocity is determined to be a fast horizontal velocity, the symmetry axis velocity is a slow horizontal velocity;

[0034] The second determination module is used to determine anisotropy parameters based on the symmetry axis velocity and the vertical velocity;

[0035] Model building module: used to build anisotropic models based on anisotropic parameters.

[0036] Optionally, the first determining module includes:

[0037] The first calculation unit is configured to extract the second first arrival data and the first first arrival data according to the fast and slow azimuth of the fitting based on the first arrival ellipse of the common center point at the micro-logging point, compare the second first arrival data with the first first arrival data, and obtain the vertical velocity corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, the preliminary value of the symmetry axis velocity corresponding to the other first arrival data, and the azimuth angle;

[0038] The first determination unit is used to determine the correction coefficient of the preliminary value of the symmetry axis velocity based on two-dimensional forward simulation and tomographic inversion with different anisotropies;

[0039] The first correction unit corrects the preliminary value of the symmetry axis velocity based on the correction coefficient to obtain the symmetry axis velocity.

[0040] Optionally, the acquisition module includes:

[0041] A first acquisition unit is configured to acquire isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data includes at least the thickness of the i-th layer, the velocity of the i-th layer, and the velocity of the last layer in the micro-logging surface structure;

[0042] The second calculation unit is used to calculate the horizontal fast speed azimuth and the horizontal slow speed azimuth of the isotropic medium by fitting the first arrival of the concentric point. The horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed.

[0043] A second acquisition unit is configured to extract second first arrival data and third first arrival data from the first arrival data obtained in the actual production based on the horizontal fast speed azimuth and the horizontal slow speed azimuth.

[0044] Optionally, the second computing unit includes:

[0045] The first control subunit is used to spatially rearrange the initial arrival according to the direction of the artillery inspection to form an elliptical spatial diagram;

[0046] The first calculation subunit is used to fit the ellipse space diagram according to the ellipse formula to calculate the ellipse inclination;

[0047] The second calculation subunit is used to calculate the horizontal fast speed azimuth and the horizontal slow speed azimuth based on the elliptical inclination angle.

[0048] Beneficial effects:

[0049] The present application provides a method for modeling the anisotropy of velocity of shallow surface media. The method compares the second initial arrival data generated in the horizontal fast speed direction and the third initial arrival data generated in the horizontal slow speed direction with the first initial arrival data of the concentric point of the micro-logging well, determines the velocity corresponding to the initial arrival data whose difference with the first initial arrival data is less than a preset difference as the vertical velocity, and determines the velocity corresponding to the other initial arrival data as the symmetry axis velocity. Based on the symmetry axis velocity and the vertical velocity, anisotropy parameters are determined, and an anisotropy model is constructed based on the anisotropy parameters. The anisotropy model established based on the anisotropy parameters takes the anisotropy factor into consideration. Therefore, when there is strong anisotropy in the surface layer, the anisotropic model has good shallow imaging effect, high deep imaging frequency, and accurate imaging depth, thereby solving the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of existing surface models. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments of the present application. 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 any creative work.

[0051] Figure 1 This is a flow chart of a shallow surface medium velocity anisotropy modeling method proposed in one embodiment of the present application;

[0052] Figure 2 This is a common-center point common-offset first-break fitting diagram of micro-well logging proposed in one embodiment of the present application;

[0053] Figure 3 This is a relationship diagram of the first initial arrival data, the second initial arrival data, and the third initial arrival data proposed in one embodiment of the present application;

[0054] Figure 4 1 is a velocity diagram of first arrival inversion in four directions proposed in one embodiment of the present application;

[0055] Figure 5 It is an ellipse fitting diagram of the speed in four directions proposed in an embodiment of the present application;

[0056] Figure 6 Schematic diagram of correction coefficients in a shallow surface medium velocity anisotropy modeling method proposed in one embodiment of the present application;

[0057] Figure 7 is a schematic diagram of the vertical velocity and the symmetry axis velocity proposed in one embodiment of the present application;

[0058] Figure 8 is a schematic diagram of anisotropic strength proposed in one embodiment of the present application;

[0059] Figure 9 This is a comparison diagram of the pre-stack depth migration effect using an anisotropic model proposed in one embodiment of the present application;

[0060] Figure 10 This is a structural block diagram of a shallow surface medium velocity anisotropy modeling device proposed in one embodiment of the present application. DETAILED DESCRIPTION

[0061] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0062] In related technologies, the velocity and thickness of the low-deceleration zone are directly used as the near-surface velocity model, and then fused with the shallow, medium and deep velocity models as the velocity model for depth domain imaging to perform depth domain offset imaging. This is called near-surface velocity modeling or surface velocity modeling for depth domain imaging of seismic data. However, this method establishes a surface model based on an isotropic medium. When there is strong anisotropy in the surface layer, it will cause the shallow imaging effect to deteriorate or even no imaging, the deep imaging frequency to decrease, and the imaging depth to be inaccurate. Therefore, when there is strong anisotropy in the surface layer, the existing surface model has poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth, which are problems that need to be solved urgently.

[0063] In view of this, the present application provides a method for modeling the anisotropy of velocity of shallow surface media. By comparing the second initial arrival data generated by the acquired horizontal fast speed direction and the third initial arrival data generated by the acquired horizontal slow speed direction with the first initial arrival data of the concentric point of the micro-logging, the velocity corresponding to the initial arrival data whose difference with the first initial arrival data is less than the preset difference is determined as the vertical velocity, and the velocity corresponding to the other initial arrival data is determined as the symmetry axis velocity. Based on the symmetry axis velocity and the vertical velocity, the anisotropy parameters are determined, and an anisotropic model is constructed based on the anisotropy parameters. The anisotropic model established based on the anisotropy parameters takes the anisotropy factor into consideration. Therefore, when there is strong anisotropy in the surface layer, the anisotropic model has good shallow imaging effect, high deep imaging frequency, and accurate imaging depth, thereby solving the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of the existing surface model.

[0064] Example 1

[0065] Reference Figure 1 , which shows a flow chart of a shallow surface medium velocity anisotropy modeling method of the present application, as shown in FIG. Figure 1 As shown, the shallow medium velocity anisotropy modeling method of the present application is applied to horizontal symmetry axis transverse isotropy (HTI) medium. The HTI medium has two mutually perpendicular symmetry planes, one of which is the isotropic plane. The velocity in the isotropic plane is the vertical velocity, which is independent of the direction. The other is the symmetry axis plane, that is, the plane where the symmetry axis is located. The velocity in the symmetry axis plane is divided into a horizontal fast speed and a horizontal slow speed. The vertical speed is the same as one of the horizontal fast speed and the horizontal slow speed, and the other speed is the symmetry axis speed. The shallow medium velocity anisotropy modeling method includes the following steps:

[0066] Step S1: Obtain the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction, wherein the first initial arrival data is the initial arrival data of the production shot when simulating the surface structure obtained by micro-logging, and the second initial arrival data and the third initial arrival data are the initial arrival data obtained in actual production.

[0067] In this embodiment, the initial arrival data includes the initial arrival time and the offset distance. The first initial arrival data is the initial arrival data of the production shot when simulating the surface structure obtained by micro-logging. The second initial arrival data and the third initial arrival data are the initial arrival data obtained in actual production.

[0068] Step S2: In the second initial arrival data and the third initial arrival data, the speed corresponding to the initial arrival data whose difference with the first initial arrival data is less than the preset difference is determined as the vertical speed, and the speed corresponding to the other initial arrival data is determined as the symmetry axis speed; that is, if the vertical speed is determined to be a slow horizontal speed, then the symmetry axis speed is a fast horizontal speed, or, if the vertical speed is determined to be a fast horizontal speed, then the symmetry axis speed is a slow horizontal speed.

[0069] Display the first arrival data, the second arrival data and the third arrival data in the same coordinate system, refer to Figure 3 , shows the relationship between the first initial arrival data, the second initial arrival data and the third initial arrival data of this application, as shown in Figure 3 As shown, the horizontal axis represents the offset distance, and the vertical axis represents the first arrival time. If the difference between the first first arrival data and a group of first arrival data in the coordinate system is less than the preset difference from the second first arrival data and the third first arrival data, then the speed corresponding to this group of first arrival data is the same as the vertical speed, and the speed corresponding to the other group of first arrival data is determined to be the symmetry axis speed.

[0070] For example: in the second initial arrival data and the third initial arrival data, the difference between the second initial arrival data and the first initial arrival data is smaller than the difference between the third initial arrival data and the first initial arrival data, and the difference between the second initial arrival data and the first initial arrival data is smaller than the preset difference, then the horizontal fast speed is the same as the vertical speed, and the horizontal slow speed is the symmetry axis speed.

[0071] In the second initial arrival data and the third initial arrival data, the difference between the third initial arrival data and the first initial arrival data is smaller than the difference between the second initial arrival data and the first initial arrival data, and the difference between the third initial arrival data and the first initial arrival data is smaller than the preset difference, then the horizontal slow speed is the same as the vertical speed, and the horizontal fast speed is the symmetry axis speed.

[0072] Step S3: Determine anisotropy parameters based on the symmetry axis velocity and the vertical velocity.

[0073] Reference Figure 8 , shows a schematic diagram of anisotropic strength of the present application, such as Figure 8 As shown in the figure, the horizontal axis is the position along the survey line, the vertical axis is the grid coordinate, and the anisotropy parameters include anisotropy intensity, symmetry axis velocity, and anisotropy orientation. The anisotropy orientation is the azimuth of the symmetry axis velocity, and the anisotropy intensity is E. P , the velocity of the symmetry axis is V ff , vertical velocity is V S , the anisotropic strength is calculated by the following formula:

[0074]

[0075] Step S4: constructing an anisotropic model based on the anisotropic parameters.

[0076] The anisotropic model is a geophysical parameter model. The geophysical parameter model uses mathematical formulas or numerical forms to characterize certain properties or laws of the earth. It is a reasonable abstraction and high-level generalization of the complex research object. After such abstraction or simplification, it should be able to better reflect or approach the essence of the object in theory or concept.

[0077] The anisotropy parameter itself takes the anisotropy factor into account, so the anisotropy model established based on the anisotropy parameter also takes the anisotropy factor into account. Therefore, when there is strong anisotropy in the surface layer, the anisotropic model has good shallow imaging effect, high deep imaging frequency, and accurate imaging depth, which solves the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of the existing surface model.

[0078] Reference Figure 9 , which shows the comparison of pre-stack depth migration effects using anisotropic model in this application, as shown in Figure 9 As shown, the left side is an isotropic model and the right side is an anisotropic model. The anisotropic model constructed in this application is a spatial velocity change model. The anisotropic model can be constructed through anisotropic parameters, and the velocities in different directions can be obtained through the anisotropic model.

[0079] The present application provides a method for modeling the anisotropy of velocity of shallow surface media. The method compares the second initial arrival data generated in the horizontal fast speed direction and the third initial arrival data generated in the horizontal slow speed direction with the first initial arrival data of the concentric point of the micro-logging well, determines the velocity corresponding to the initial arrival data whose difference with the first initial arrival data is less than a preset difference as the vertical velocity, and determines the velocity corresponding to the other initial arrival data as the symmetry axis velocity. Based on the symmetry axis velocity and the vertical velocity, anisotropy parameters are determined, and an anisotropy model is constructed based on the anisotropy parameters. The anisotropy model established based on the anisotropy parameters takes the anisotropy factor into consideration. Therefore, when there is strong anisotropy in the surface layer, the anisotropic model has good shallow imaging effect, high deep imaging frequency, and accurate imaging depth, thereby solving the problems of poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth of existing surface models.

[0080] Based on the above-mentioned shallow medium velocity anisotropy modeling method, the present application provides the following examples of specific implementable methods. Under the premise that they do not conflict with each other, the various examples can be arbitrarily combined to form another shallow medium velocity anisotropy modeling method. It should be understood that the shallow medium velocity anisotropy modeling method formed by combining any of the examples should fall within the scope of protection of the present application.

[0081] In a feasible implementation, among the second and third initial arrival data, a velocity corresponding to the initial arrival data having a difference with the first initial arrival data that is less than a preset difference is determined as the vertical velocity, and a velocity corresponding to the other initial arrival data is determined as the symmetry axis velocity, including the following steps:

[0082] Step S21: Based on the fitting of the common center point initial arrival ellipse at the micro-logging point, the second initial arrival data and the first initial arrival data are extracted according to the fast and slow azimuth of the fitting, and compared with the first initial arrival data to obtain the vertical velocity corresponding to the initial arrival data whose difference with the first initial arrival data is less than the preset difference, the preliminary velocity value corresponding to the other initial arrival data, and the azimuth angle.

[0083] The first arrival data are grouped according to azimuth, and the grouped first arrival data are subjected to tomographic inversion to obtain the vertical velocity corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, the preliminary velocity value corresponding to the other first arrival data, and the azimuth angle.

[0084] Step S22: Based on the two-dimensional forward modeling and tomographic inversion of different anisotropies, a correction coefficient of the preliminary value of the symmetry axis velocity is determined.

[0085] Two-dimensional forward modeling refers to considering the plane where the vertical velocity is located and establishing a vertical velocity model based on different anisotropic parameters. The vertical velocity is independent of direction, so the vertical velocity model is also independent of velocity. The vertical velocity model established for the anisotropic parameters is subjected to tomographic inversion to determine the correction coefficient of the preliminary value of the symmetry axis velocity.

[0086] Step S23: Correcting the preliminary value of the symmetry axis velocity based on the correction coefficient to obtain the symmetry axis velocity.

[0087] The correction coefficient is K, the initial value of the symmetry axis speed is Vf, the vertical speed is Vs, and the symmetry axis speed is Vff. Then the symmetry axis speed is calculated using the following formula:

[0088] Vff=(Vf-Vs)K+Vs

[0089] In a feasible embodiment, obtaining the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction includes:

[0090] Step S11: obtaining isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data at least includes the thickness of the i-th layer, the velocity of the i-th layer and the velocity of the last layer in the micro-logging surface structure.

[0091] The micro-logging result data is the survey data obtained from the micro-logging survey point. The result data at least includes the thickness h of the i-th layer in the surface structure of the micro-loggingi , the speed v of the i-th layer i And the speed v of the last layer p , the offset distance is Ofst k =0,10,20,…2000m, i is 2,…P, P is the number of layers of the surface structure, and k is 1,2,…201.

[0092]

[0093]

[0094] Tw k =min(Ttmp i,k )

[0095] By calculating the above formula, the first arrival data of micro-logging calculation is obtained as follows: Offset discrete distance Ofst k , first arrival time Tw k .

[0096] Step S12: Calculate the horizontal fast speed azimuth and horizontal slow speed azimuth of the anisotropic medium by fitting the first arrivals of the concentric points. The horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed.

[0097] Reference Figure 2 , shows the initial arrival fitting diagram of the common center point and common offset of the micro-logging of this application, as shown in Figure 2 As shown in the figure, the first arrival time of the concentric point at the micro-logging survey point is extracted, the first arrival travel time is spatially rearranged according to the shot inspection direction, and then an ellipse fitting is performed to calculate the horizontal fast speed azimuth and horizontal slow speed azimuth of the anisotropic medium. The horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed.

[0098] Step S13: Based on the horizontal fast speed azimuth and the horizontal slow speed azimuth, extract the second first arrival data and the third first arrival data from the first arrival data obtained in actual production.

[0099] Based on the horizontal fast speed azimuth and the horizontal slow speed azimuth, second first arrival data and third first arrival data that meet the conditions are extracted from the first arrival data obtained in actual production.

[0100] In another feasible implementation, the horizontal fast velocity azimuth and the horizontal slow velocity azimuth of the anisotropic medium are calculated by fitting the first arrivals of the concentric points, including the following steps:

[0101] Step S121: spatially rearrange the initial arrival travel time according to the direction of the artillery inspection to form an elliptical spatial diagram.

[0102] The shot detection direction is the direction from the shot point to the geophone, and the shot point is the location where the seismic wave is excited. For example, the first arrival time of the common center point at the micro-well survey point is extracted, and the first arrival with an offset of 2 times the thickness of the low-velocity drop zone is selected for ellipse fitting. To ensure sufficient fitting data, the range of the extracted common center point can be expanded to 3 to 5 times the natural bin size, and the offset range can be one to two trace spacings.

[0103] The coordinates of the excitation point of the selected data are recorded as SX i ,SY i , the receiving point coordinates are Rx i 、Ry i , when I first arrived on the trip, it was Fbt i , i = 1, 2, ..., N, where N is the number of first arrivals selected and the coordinates of the center point of the micro-well are X0, Y0. The first arrivals are spatially rearranged according to the direction of the shot detection using the following formula:

[0104] Fx i =Fbt i (Sx i -Rx i ) / ((Sx i -Rx i ) 2 +(Sy i -Ry i ) 2 )) 0.5 +X0

[0105] Fy i =Fbt i (Sy i -Ry i ) / ((Sx i -Rx i ) 2 +(Sy i -Ry i ) 2 )) 0.5 +Y0

[0106] Step S122: fitting the ellipse space diagram according to the ellipse formula to calculate the ellipse inclination.

[0107] For Fx i 、Fy i According to the ellipse formula Ax 2 +Bxy+Cy 2 +Dx+Ey+F=0 for fitting, the ellipse inclination calculation formula is:

[0108] Step S123: Determine the horizontal fast speed azimuth and the horizontal slow speed azimuth based on the elliptical inclination angle.

[0109] Based on the ellipse inclination angle θ, it can be concluded that θ and θ+π / 2 are the fast and slow speeds or the slow and fast speed directions respectively.

[0110] In a feasible embodiment, based on fitting the common center point first arrival ellipse at the micro-logging point, extracting the second first arrival data and the first first arrival data according to the fast and slow azimuth of the fitting, and comparing them with the first first arrival data, obtaining the vertical velocity, preliminary value of the symmetry axis velocity, and azimuth angle corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, including the following steps:

[0111] Step S211: Determine the azimuths of all shot-detection pairs, divide the first arrival data into multiple groups according to the azimuths, and perform tomographic inversion on the multiple groups of first arrival data to obtain multiple groups of velocity volume data.

[0112] Calculate the azimuth angles of all shot detection pairs using the following formula:

[0113] Azi j =arctan((SY i -RY i ) / ((SX i -RX i ))

[0114] According to the azimuth, the first arrival data are divided into multiple groups. For example, the first arrival data are divided into 4 groups. The azimuths of the 4 groups of first arrival data are: the first group of azimuths: between [0°-22.5°0°+22.5°] and [180°-22.5°180°+22.5°], the second group of azimuths: between [45°-22.5°45°+22.5°] and [135°-22.5°135°+22.5°], the third group of azimuths: between [90°-22.5°90°+22.5°] and [270°-22.5°270°+22.5°], and the fourth group of azimuths: between [135°-22.5°135°+22.5°] and [315°-22.5°315°+22.5°].

[0115] The 4 sets of first arrival data were subjected to tomographic inversion respectively, and 4 sets of velocity volume data were obtained. Figure 4 , shows the velocity diagram of the first arrival inversion in four directions of this application, such as Figure 4 As shown, denoted as Vt k,l,m,n , k=1,2,3,4, representing 4 directions, l=1,2……R, R represents the number of data along the detection line, m=1,2……S, S represents the number of data in the direction of the vertical detection line, n=1,2……T, T represents the number of vertical data.

[0116] Step S212: spatially rearrange the multiple sets of velocity volume data to form a velocity ellipse spatial diagram.

[0117] The speed at each position is recorded as: Vx i 、Vy i ,, spatially rearrange the four groups of velocities according to the following formula:

[0118] Vx 1,l,m,n =Vt 1,l,m,n

[0119] Vy 1,l,m,n =0

[0120] Vx 2,l,m,n =Vt 2,l,m,n cos(45°)

[0121] Vy 2,l,m,n =Vt 2,l,m,n sin(45°)

[0122] Vx 3,l,m,n =0

[0123] Vy 3,l,m,n =Vt 3,l,m,n

[0124] Vx 4,l,m,n =Vt 4,l,m,n cos(135°)

[0125] Vy 4,l,m,n =Vt 4,l,m,n sin(135°)

[0126] Vx 5,l,m,n =-Vt 1,l,m,n

[0127] Vy 5,l,m,n =0

[0128] Vx 6,l,m,n =-Vt 2,l,m,n cos(45°)

[0129] Vy 6,l,m,n =-Vt 2,l,m,n sin(45°)

[0130] Vx 7,l,m,n =0

[0131] Vy 7,l,m,n =-Vt 3,l,m,n

[0132] Vy 8,l,m,n =-Vt 4,l,m,n cos(135°)

[0133] Vy 8,l,m,n =-Vt 4,l,m,n sin(135°).

[0134] Step S213: Fit the velocity at each position according to the ellipse formula to obtain the vertical velocity, preliminary values ​​of the symmetry axis velocity, and azimuth angle.

[0135] Reference Figure 5 , shows the elliptical fitting diagram of the speed in four directions of the application step, such as Figure 5 As shown, for each position Vx i 、Vy i According to the ellipse formula Ax 2 +Bxy+Cy 2 +Dx+Ey+F=0 for fitting, A, B, C, D, E, F are ellipse coefficients, Axis1 and Axis2 are the lengths of the two semi-axes in the ellipse respectively, and the inclination of the ellipse is:

[0136]

[0137]

[0138]

[0139]

[0140] Reference Figure 7 , shows a schematic diagram of the vertical velocity and the symmetry axis velocity of this application, as shown in Figure 7 As shown in the figure, the horizontal axis is the position along the survey line, and the vertical axis is the grid coordinate. The formula min(Axis1,Axis2) is used to obtain the horizontal slow speed of the entire surface layer, and the formula max(Axis1,Axis2) is used to obtain the horizontal fast speed of the entire surface layer. For example: if the horizontal slow speed is the same as the vertical speed, then min(Axis1,Axis2) is the vertical speed, and max(Axis1,Axis2) is the preliminary value of the symmetry axis speed; using the formula The ellipse inclination angle corresponding to the preliminary value of the symmetry axis velocity is obtained, that is, the azimuth angle of the preliminary value of the symmetry axis velocity.

[0141] In a feasible embodiment, determining a correction coefficient for a preliminary value of the symmetry axis velocity based on two-dimensional forward modeling and tomographic inversion with different anisotropies includes the following steps:

[0142] Step S221: establishing a vertical velocity model based on the surface structure investigated by micro-well logging, and establishing multiple vertical velocity models using multiple anisotropic parameters.

[0143] The vertical velocity is independent of direction, so the vertical velocity model is also independent of velocity. For example, six anisotropic models are established with anisotropy parameters Emi = 0, 0.1, 0.2, 0.3, 0.4, and 0.5 respectively. Assuming that the vertical velocity is consistent with the horizontal fast speed, Emi = 0, -0.1, -0.2, -0.3, and -0.4.

[0144] Step S222: performing tomographic inversion based on the forward modeling data of the multiple vertical velocity models to obtain the velocity of each vertical velocity model.

[0145] The velocity obtained by tomographic inversion using the forward data of these models is recorded as Vm i,k ,k is 1, 2, ... W, W is the number of grids to the depth of the high-speed layer of micro-logging survey.

[0146] Step S223: Determine a correction coefficient for the preliminary value of the symmetry axis velocity based on the velocity of each vertical velocity model.

[0147] Reference Figure 6 , which shows a schematic diagram of the correction coefficients in the shallow surface medium velocity anisotropy modeling method of this application, as shown in Figure 6 As shown in the figure, the horizontal axis is depth and the vertical axis is the correction coefficient K. The correction coefficient of the preliminary velocity value is calculated by the following formula, where m = 1, 2...S, S represents the number of data in the vertical detection line direction, i = 1, 2, ..., 6, and j = 2, 3, ..., 6:

[0148]

[0149]

[0150]

[0151] In combination with the above embodiments, in one feasible implementation manner, a method for constructing an anisotropic model is exemplarily provided, including the following steps:

[0152] 1. Prepare basic data:

[0153] (a) Micro-logging data: geodetic coordinates of survey points, observation depth, and micro-logging interpretation results.

[0154] (b) First arrival data: the first arrival time of earthquake data.

[0155] (c) Tomographic inversion velocity in four azimuths. The four azimuths are: the first group of azimuths: between [0°-22.5°0°+22.5°] and [180°-22.5°180°+22.5°], the second group of azimuths: between [45°-22.5°45°+22.5°] and [135°-22.5°135°+22.5°], the third group of azimuths: between [90°-22.5°90°+22.5°] and [270°-22.5°270°+22.5°], and the fourth group of azimuths: between [135°-22.5°135°+22.5°] and [315°-22.5°315°+22.5°].

[0156] (d) Forward modeling data and tomographic inversion velocities of six anisotropic models with anisotropy intensities of 0, 0.1, 0.2, 0.3, 0.4, and 0.5, respectively.

[0157] 2. Calculate the first arrival time using micro-logging interpretation results

[0158] According to the method of step S11 of the present application, the first arrival time is calculated using the micro-logging results.

[0159] 3. Calculate the azimuth of the horizontal speed

[0160] According to steps S121 and S122 of the present application, the concentric points are fitted and the inclination of the ellipse is calculated.

[0161] 4. Determine the isotropic surface characteristics

[0162] According to the method of step S2 of the present application, it is determined whether the vertical speed is the same as the horizontal fast speed or the horizontal slow speed.

[0163] 5. Calculate the preliminary values ​​of vertical velocity and symmetry axis velocity

[0164] The vertical speed, the horizontal slow speed and the preliminary horizontal fast speed are calculated according to the method of steps S211 to S213 of the present application.

[0165] 6. Calculate the correction coefficient of the preliminary value of the symmetry axis velocity

[0166] The correction coefficient of the horizontal fast speed is obtained according to the method of steps S221 to S223 of the present application.

[0167] 7. Calculate the velocity of the symmetry axis

[0168] The preliminary value of the symmetry axis velocity is corrected by the obtained correction coefficient to obtain the symmetry axis velocity.

[0169] 8. Calculate anisotropic parameters

[0170] The anisotropy parameters are calculated according to the method of step S3 of the present application.

[0171] Example 2

[0172] Based on the same inventive concept, another embodiment of the present application provides a shallow medium velocity anisotropy modeling device, which is used to execute the shallow medium velocity anisotropy modeling method provided in the first embodiment of the present application; Figure 10 , shows the structural block diagram of the shallow surface medium velocity anisotropy modeling device, as shown in Figure 10 As shown in FIG, the shallow surface medium velocity anisotropy modeling device includes:

[0173] Acquisition module 11: used to obtain the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction; wherein the first initial arrival data is the initial arrival data of the production shot when simulating the surface structure obtained by micro-logging, and the second and third initial arrival data are the initial arrival data obtained in actual production;

[0174] The first determination module 12 is configured to determine, among the second and third initial arrival data, a velocity corresponding to the initial arrival data having a difference with the first initial arrival data that is less than a preset difference as the vertical velocity, and to determine a velocity corresponding to the other initial arrival data as the symmetry axis velocity; that is, if the vertical velocity is determined to be a slow horizontal velocity, the symmetry axis velocity is a fast horizontal velocity, or if the vertical velocity is determined to be a fast horizontal velocity, the symmetry axis velocity is a slow horizontal velocity;

[0175] The second determining module 13 is used to determine anisotropy parameters based on the symmetry axis velocity and the vertical velocity;

[0176] Model building module 14: used for building an anisotropic model based on anisotropic parameters.

[0177] The present application provides a shallow surface medium velocity anisotropy modeling device.

[0178] In a feasible implementation, the first determining module 12 includes:

[0179] The first calculation unit 121 is configured to extract the second first arrival data and the first first arrival data according to the fast and slow azimuth of the fitting based on the first arrival ellipse of the common center point at the micro-logging point, compare the second first arrival data with the first first arrival data, and obtain the vertical velocity corresponding to the first arrival data whose difference with the first arrival data is less than a preset difference, the preliminary value of the symmetry axis velocity corresponding to the other first arrival data, and the azimuth angle;

[0180] The first determining unit 122 is used to determine the correction coefficient of the preliminary value of the symmetry axis velocity based on the two-dimensional forward simulation and tomographic inversion of different anisotropies;

[0181] The first correction unit 123 corrects the preliminary value of the symmetry axis velocity based on the correction coefficient to obtain the symmetry axis velocity.

[0182] The shallow surface medium velocity anisotropy modeling device provided in the present application compares the second initial arrival data generated in the horizontal fast speed direction and the third initial arrival data generated in the horizontal slow speed direction with the first initial arrival data of the concentric point of the micro-logging well, determines the velocity corresponding to the initial arrival data whose difference with the first initial arrival data is less than a preset difference as the vertical velocity, and determines the velocity corresponding to the other initial arrival data as the symmetry axis velocity. Based on the symmetry axis velocity and the vertical velocity, anisotropy parameters are determined, and an anisotropy model is constructed based on the anisotropy parameters. The anisotropy model established based on the anisotropy parameters takes the anisotropy factor into consideration. Therefore, when there is strong anisotropy in the surface layer, the anisotropic model has good shallow imaging effect, high deep imaging frequency, and accurate imaging depth, thereby solving the urgent problems of the existing surface model, such as poor shallow imaging effect, low deep imaging frequency, and inaccurate imaging depth.

[0183] In a feasible implementation, the acquisition module 11 includes:

[0184] A first acquisition unit 111 is configured to acquire isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data includes at least the thickness of the i-th layer, the velocity of the i-th layer, and the velocity of the last layer in the micro-logging surface structure;

[0185] The second calculation unit 112 is configured to calculate the horizontal fast speed azimuth and the horizontal slow speed azimuth of the isotropic medium by fitting the first arrivals of the concentric points. The horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed.

[0186] The second acquisition unit 113 is configured to extract second first arrival data and third first arrival data from the first arrival data obtained in the actual production based on the horizontal fast speed azimuth and the horizontal slow speed azimuth.

[0187] In a feasible implementation, the second calculation unit 112 includes:

[0188] The first control subunit 1121 is used to spatially rearrange the initial arrival travel time according to the direction of the artillery inspection to form an elliptical spatial diagram;

[0189] The first calculation subunit 1122 is used to fit the ellipse space diagram according to the ellipse formula to calculate the ellipse inclination;

[0190] The second calculation subunit 1123 is configured to calculate a horizontal fast speed azimuth and a horizontal slow speed azimuth based on the elliptical inclination angle.

[0191] In another feasible implementation, the first calculation unit 121 includes:

[0192] The third calculation subunit 1211 is used to calculate the azimuths of all shot-detection pairs, divide the first arrival data into multiple groups according to the azimuths, and perform tomographic inversion on the multiple groups of first arrival data to obtain multiple groups of velocity volume data;

[0193] The second control subunit 1212 is used for spatially rearranging the multiple sets of velocity volume data to form a velocity ellipse spatial map;

[0194] The fourth calculation subunit 1213 is used to fit the velocity at each position according to the ellipse formula to obtain the vertical velocity, preliminary values ​​of the symmetry axis velocity and the azimuth angle.

[0195] In a feasible implementation manner, the first determining unit 122 includes:

[0196] The first construction subunit 1221 is used to establish a vertical velocity model based on the surface structure investigated by micro-well logging, and to establish multiple vertical velocity models using multiple anisotropic parameters.

[0197] The fifth calculation subunit 1222 is configured to perform tomographic inversion based on the forward modeling data of the multiple vertical velocity models to obtain the velocity of each vertical velocity model.

[0198] The sixth calculation subunit 1223 is configured to obtain a correction coefficient of a preliminary value of the symmetry axis velocity based on the velocity calculation of each vertical velocity model.

[0199] As for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment.

[0200] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0201] It should be understood that although the present specification has described preferred embodiments of the present invention, those skilled in the art may make additional changes and modifications to these embodiments once they understand the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0202] The above is a detailed introduction to a method and device for modeling velocity anisotropy of shallow surface media provided by the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method and core ideas of the present application. At the same time, for general technicians in this field, based on the ideas of the present 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 a limitation on the present application.

Claims

1. A method for modeling velocity anisotropy in shallow surface media, applied to transversely isotropic media with a horizontal symmetry axis, characterized in that: The method comprises: Acquire the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction; The first initial arrival data is the initial arrival data of a production shot when simulating the surface structure obtained by the micro-logging, and the second initial arrival data and the third initial arrival data are the initial arrival data obtained in actual production; In the second first arrival data and the third first arrival data, the speed corresponding to the first arrival data whose difference with the first first arrival data is less than the preset difference is determined as the vertical speed, and the speed corresponding to the other first arrival data is determined as the symmetry axis speed; that is, if the vertical speed is determined to be the horizontal slow speed, then the symmetry axis speed is the horizontal fast speed, or if the vertical speed is determined to be the horizontal fast speed, then the symmetry axis speed is the horizontal slow speed; determining an anisotropy parameter based on the symmetry axis velocity and the vertical velocity; An anisotropic model is constructed based on the anisotropic parameters.

2. The method according to claim 1, characterized in that In the second and third first arrival data, determining a velocity corresponding to first arrival data having a difference with the first arrival data that is less than a preset difference as a vertical velocity, and determining a velocity corresponding to another first arrival data as a symmetry axis velocity, includes: Based on fitting a common center point first arrival ellipse at the micro-logging point, extracting the second first arrival data and the first first arrival data according to the fast and slow azimuths of the fitting, and comparing them with the first first arrival data to obtain the vertical velocity, the preliminary value of the symmetry axis velocity, and the azimuth angle corresponding to the first arrival data whose difference from the first arrival data is less than a preset difference; Determining a correction coefficient for the preliminary value of the symmetry axis velocity based on two-dimensional forward modeling and tomographic inversion with different anisotropies; The preliminary value of the symmetry axis velocity is corrected based on the correction coefficient to obtain the symmetry axis velocity.

3. The method according to claim 1, characterized in that Acquiring the first initial arrival data of the common center point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction, including: Obtaining isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data at least includes the thickness of the i-th layer, the velocity of the i-th layer, and the velocity of the last layer in the micro-logging surface structure; By fitting the first arrivals of the concentric points, the horizontal fast speed azimuth and the horizontal slow speed azimuth of the anisotropic medium are calculated, wherein the horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed; Based on the horizontal fast speed azimuth and the horizontal slow speed azimuth, the second first arrival data and the third first arrival data are extracted from the first arrival data obtained in the actual production.

4. The method according to claim 3, characterized in that By fitting the first arrivals of the concentric points, the horizontal fast velocity azimuth and the horizontal slow velocity azimuth of the anisotropic medium are calculated, including: Rearrange the space according to the direction of the gun inspection when the initial arrival is made, forming an elliptical space diagram; Fitting the ellipse space diagram according to the ellipse formula to calculate the ellipse inclination; Based on the elliptical inclination angle, the horizontal fast speed azimuth angle and the horizontal slow speed azimuth angle are determined.

5. The method according to claim 2, characterized in that Based on fitting the common center point first arrival ellipse at the micro-logging point, extracting the second first arrival data and the first first arrival data according to the fast and slow azimuths of the fitting, and comparing them with the first first arrival data, obtaining the vertical velocity, the preliminary value of the symmetry axis velocity, and the azimuth angle corresponding to the first arrival data whose difference with the first first arrival data is less than a preset difference, including: determining the azimuths of all shot-detection pairs, dividing the first arrival data into multiple groups according to the azimuths, and performing tomographic inversion on the multiple groups of first arrival data to obtain multiple groups of velocity volume data; spatially rearranging the plurality of sets of velocity volume data to form a velocity ellipse spatial map; The velocity at each position is fitted according to the ellipse formula to obtain the vertical velocity, the preliminary value of the symmetry axis velocity and the azimuth angle.

6. The method according to claim 2, characterized in that Based on two-dimensional forward modeling and tomographic inversion with different anisotropies, the correction coefficient of the preliminary value of the symmetry axis velocity is determined, including: Establishing a vertical velocity model based on the surface structure investigated by the micro-well logging, and establishing a plurality of vertical velocity models based on a plurality of anisotropic parameters; Based on the forward modeling data of the plurality of vertical velocity models, performing tomographic inversion to obtain the velocity of each vertical velocity model; A correction coefficient for the preliminary value of the symmetry axis velocity is determined based on the velocity of each vertical velocity model.

7. A shallow surface medium velocity anisotropy modeling device, applied to a horizontally symmetric axis transversely isotropic medium, characterized in that: The device comprises: Acquisition module: used to acquire the first initial arrival data of the concentric point of the micro-logging, the second initial arrival data generated in the horizontal fast speed direction, and the third initial arrival data generated in the horizontal slow speed direction; wherein the first initial arrival data is the initial arrival data of the production shot when simulating the surface structure obtained by the micro-logging, and the second initial arrival data and the third initial arrival data are the initial arrival data obtained in actual production; A first determining module is configured to determine, among the second and third first arrival data, a speed corresponding to the first arrival data having a difference less than a preset difference from the first arrival data as the vertical speed, and to determine a speed corresponding to the other first arrival data as the symmetry axis speed; that is, if the vertical speed is determined to be the horizontal slow speed, the symmetry axis speed is the horizontal fast speed, or if the vertical speed is determined to be the horizontal fast speed, the symmetry axis speed is the horizontal slow speed; A second determining module is configured to determine an anisotropy parameter based on the symmetry axis velocity and the vertical velocity; Model building module: used for building an anisotropic model based on the anisotropic parameters.

8. The device according to claim 7, characterized in that The first determining module includes: A first calculation unit is configured to extract the second first arrival data and the first first arrival data according to the fast and slow azimuths of the fitting based on the first arrival ellipse of the common center point at the micro-logging point, compare the second first arrival data and the first first arrival data with the first first arrival data, and obtain the vertical velocity, the preliminary value of the symmetry axis velocity, and the azimuth angle corresponding to the first arrival data whose difference with the first first arrival data is less than a preset difference; A first determining unit is configured to determine a correction coefficient for the preliminary value of the symmetry axis velocity based on two-dimensional forward modeling and tomographic inversion with different anisotropies; A first correction unit is configured to correct the preliminary value of the symmetry axis velocity based on the correction coefficient to obtain the symmetry axis velocity.

9. The device according to claim 7, characterized in that The acquisition module includes: a first acquisition unit configured to acquire isotropic first arrival data of different offsets corresponding to the micro-logging surface structure based on the micro-logging result data; wherein the result data at least includes the thickness of the i-th layer, the velocity of the i-th layer, and the velocity of the last layer in the micro-logging surface structure; A second calculation unit is configured to calculate a horizontal fast speed azimuth and a horizontal slow speed azimuth of the isotropic medium by fitting the first arrivals of the concentric points, wherein the horizontal fast speed azimuth is used to determine the direction of the horizontal fast speed, and the horizontal slow speed azimuth is used to determine the direction of the horizontal slow speed; A second acquisition unit is configured to extract the second first arrival data and the third first arrival data from the first arrival data obtained in the actual production based on the horizontal fast speed azimuth and the horizontal slow speed azimuth.

10. The device according to claim 9, characterized in that The second calculation unit includes: The first control subunit is used to spatially rearrange the initial arrival according to the direction of the artillery inspection to form an elliptical spatial diagram; A first calculation subunit is configured to fit the ellipse space diagram according to an ellipse formula to calculate the ellipse inclination angle; The second calculation subunit is configured to calculate the horizontal fast speed azimuth and the horizontal slow speed azimuth based on the elliptical inclination angle.

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