Method and device for constructing stratigraphic shear wave velocity data volume

Abstract

The invention discloses a method and a device for constructing a stratigraphic shear wave velocity data body. The method comprises the following steps: aiming at each sampling point in four-component waveform data of cross dipole acoustic logging of a target interval, respectively executing the following operations: determining dipole waveforms in N orientations according to the four-component waveform data; according to the dipole waveforms in the N orientations, respectively calculating a bending wave frequency dispersion curve of each orientation in a frequency domain, and calculating shear wave velocity data of the corresponding orientation by adopting a frequency dispersion curve constraint inversion technology; carrying out interpolation on the shear wave velocity data in the N directions to obtain the interpolated shear wave velocity data corresponding to the sampling point; wherein N is an integer greater than 4; and determining a shear wave velocity data body of the target interval according to the shear wave velocity data after all sampling points are interpolated.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas exploration technology, and in particular to a method and device for constructing a formation shear wave velocity data body. Background Art

[0002] In the process of acoustic wave processing and interpretation, traditional methods generally assume that at a certain depth point, the shear wave velocity near the wellbore is uniformly distributed. In the actual drilling process, factors such as rock mechanical crushing, wellbore stress concentration, and mud invasion often cause the shear wave velocity of the formation near the wellbore to be different from the shear wave velocity of the original formation. The shear wave radial velocity profile inversion technology can obtain the shear wave velocity of the formation at different radial depths near the wellbore, which is of great significance for evaluating the brittleness and fracturability of the formation and constructing a high-quality initial model of long-range acoustic wave velocity.

[0003] With the increasing complexity of exploration targets and the further application of acoustic logging data, the two-dimensional shear wave radial velocity profile can no longer meet the needs of practical applications. The current three-dimensional shear wave velocity analysis method near the wellbore mainly uses the four-component waveform data measured by the cross-dipole mode of array acoustic logging, combined with travel-time tomography technology to perform three-dimensional shear wave velocity analysis around the wellbore, but this method is relatively time-consuming in actual calculations; therefore, it is an urgent problem to realize a method for constructing a formation shear wave velocity data body that is simple, easy to implement, and has a high actual processing efficiency. Summary of the invention

[0004] The present application provides a method and device for constructing a formation shear wave velocity data body. The method uses four-component waveform data of cross-dipole acoustic logging to calculate dipole waveforms in several specified azimuths, adopts dispersion curve constrained inversion technology to calculate the shear wave radial velocity profile in each azimuth, and uses multi-azimuth radial shear wave velocity profiles to interpolate to obtain a three-dimensional shear wave velocity body of the target layer segment. The method is simple and easy to implement, has a high actual processing efficiency, and is easy to promote and apply.

[0005] In a first aspect, the present application provides a method for constructing a formation shear wave velocity data volume, the method comprising:

[0006] The following operations are performed for each sampling point in the four-component waveform data of the cross-dipole acoustic logging of the target layer:

[0007] Determine the dipole waveforms at N directions according to the four-component waveform data; calculate the bending wave dispersion curve in the frequency domain of each direction according to the dipole waveforms at the N directions, and calculate the shear wave velocity data of the corresponding direction using the dispersion curve constrained inversion technology; interpolate the shear wave velocity data at the N directions to obtain the interpolated shear wave velocity data corresponding to the sampling point; wherein N is an integer greater than 4;

[0008] The shear wave velocity data volume of the target layer segment is determined according to the shear wave velocity data after interpolation of all sampling points.

[0009] In an exemplary embodiment, relevant preprocessing operations are performed on the four-component waveform data of the cross-dipole acoustic logging of the target layer, wherein the preprocessing operations include one or more of the following:

[0010] Start time correction, waveform degaining and digital filtering.

[0011] In an exemplary embodiment, determining the dipole waveforms in N directions according to the four-component waveform data includes:

[0012] According to the four-component waveform data, the dipole waveforms in N directions are calculated respectively using the coordinate rotation equation, wherein the coordinate rotation equation is:

[0013] W(θ)=W XX cos 2 θ+(W XY +W YX )sinθcosθ+W YY sin 2 θ

[0014] Where W(θ) is the dipole waveform at the θ azimuth angle; θ is the azimuth angle; W XX is the four-component waveform data in the XX direction, W XY is the four-component waveform data in the XY direction, W YX is the four-component waveform data in the YX direction, W YY They are four-component waveform data in the YY direction respectively.

[0015] In an exemplary embodiment, the calculating the bending wave dispersion curve in the frequency domain of each orientation according to the dipole waveforms in the N orientations respectively includes:

[0016] Performing Fourier transformation on the dipole waveform in each of the N directions to obtain a spectrum of the dipole waveform and a conjugate spectrum of the dipole waveform;

[0017] For each angular frequency value, using a spectral coherence function according to the spectrum of the dipole waveform and the conjugate spectrum of the dipole waveform, respectively determine the spectral coherence function values ​​of the azimuthal dipole waveform under each set bending wave velocity value, and use the bending wave velocity corresponding to the maximum value of the spectral coherence function as the bending wave velocity at the angular frequency;

[0018] The bending wave dispersion curve is obtained according to the bending wave velocity at each angular frequency.

[0019] In an exemplary embodiment, the spectral coherence function is:

[0020]

[0021] Where ρ(ω, V) is the value of the spectral coherence function; X m (ω) is the spectrum of the dipole waveform; is the conjugate spectrum of the dipole waveform; M is the number of receivers of the cross-dipole acoustic logging instrument, m represents the receiver number; V is the bending wave velocity; ω is the angular frequency; l is the distance between two adjacent receivers.

[0022] In an exemplary embodiment, the method of calculating the shear wave velocity data of the corresponding azimuth using the dispersion curve constrained inversion technique includes:

[0023] According to the bending wave dispersion curve, the homogeneous formation dispersion curve and the theoretical dispersion curve at each of the N directions, an inversion objective function of the thickness and shear wave velocity of the variable zone formation in the radial layered formation model is established;

[0024] The minimum value of the inversion objective function is determined by the least square method within the preset variation zone formation thickness and shear wave velocity parameter values, and the shear wave velocity corresponding to the minimum value is used as the shear wave velocity of the variation zone formation corresponding to the azimuth.

[0025] In an exemplary embodiment, the dispersion curve of the homogeneous formation is determined by the following steps:

[0026] Determine the wave number at different angular frequencies using a dispersion equation of multipole acoustic wave propagation in a homogeneous formation according to the wellbore radius, formation density, formation P-wave velocity, shear wave velocity of the change zone formation, wellbore fluid density and fluid velocity;

[0027] According to the determined wave numbers at different angular frequencies, the dispersion curve of the homogeneous formation at the corresponding shear wave velocity of the homogeneous formation is calculated.

[0028] In an exemplary embodiment, the inversion objective function of the thickness and shear wave velocity of the variable zone strata in the radially layered stratum model is:

[0029]

[0030] In the formula, E(d, V S1 ) is the inversion residual of the objective function; d is the formation thickness of the variable zone; V(ω) is the flexural wave dispersion curve; V s1 is the shear wave velocity of the variable zone formation; V1(ω) is the dispersion curve of the homogeneous formation; V2(ω, d, V S1 ) is the theoretical dispersion curve; Ω is the preset inversion processing frequency band; Ω′ is the preset inversion constraint frequency band; λ is the weight factor.

[0031] In an exemplary embodiment, after calculating the shear wave velocity of the formation in the variation zone of the corresponding azimuth using the dispersion curve constrained inversion technique, the method further includes:

[0032] According to the shear wave velocity of the formation in the change zone and the shear wave velocity of the original formation, the shear wave velocity formula of the formation at different radial depths is used to determine the shear wave velocity of the formation at different radial depths in the azimuth;

[0033] Determine the formation shear wave velocity at different radial depths in N directions according to the formation shear wave velocity of the variation zone in each direction;

[0034] The formula for the shear wave velocity of the formation at different radial depths is:

[0035]

[0036] In the above formula, V S (r) is the shear wave velocity of the formation at different radial depths; V S2 is the shear wave velocity of the original formation; is the shear wave velocity of the formation in the variation zone obtained by inversion; a is the wellbore radius; r is the radial distance from the wellbore wall.

[0037] In an exemplary embodiment, interpolating the N azimuth radial shear wave velocity data to obtain interpolated shear wave velocity data corresponding to the sampling point includes:

[0038] Establishing a wellbore shear wave velocity polar coordinate model, and performing radial and circumferential mesh discretization processing under the polar coordinate model;

[0039] Convert the discretized grid coordinates into a rectangular coordinate system;

[0040] In the rectangular coordinate system, the interpolation algorithm is used to interpolate the formation shear wave velocity at N directions to obtain the interpolated shear wave velocity data corresponding to the sampling point;

[0041] Wherein, the interpolation algorithm is:

[0042] Interpolate in the x direction:

[0043] Interpolate in the y direction:

[0044] In the above formula, x=r cosθ, y=r sinθ; (x1, y1) and (x2, y2) are the coordinate values ​​of two points respectively; and v is the shear wave velocity.

[0045] In a second aspect, an embodiment of the present invention provides a device for constructing a formation shear wave velocity data body, the device comprising: a memory and a processor; the memory is used to store a program for constructing a formation shear wave velocity data body, and the processor is used to read and execute the program for constructing a formation shear wave velocity data body, and execute the method for constructing a formation shear wave velocity data body described in any one of the above embodiments.

[0046] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium having a data processing program stored thereon, and the data processing program is executed by a processor to perform the method for constructing a formation shear wave velocity data body as described in any one of the above embodiments.

[0047] Compared with the related art, the present application provides a method and device for constructing a formation shear wave velocity data body, the method comprising: performing the following operations for each sampling point in the four-component waveform data of the cross-dipole acoustic logging of the target layer segment: determining the dipole waveforms in N azimuths according to the four-component waveform data; calculating the bending wave dispersion curve in the frequency domain of each azimuth according to the dipole waveforms in the N azimuths, and calculating the shear wave velocity data of the corresponding azimuth using the dispersion curve constrained inversion technology; interpolating the shear wave velocity data in the N azimuths to obtain the interpolated shear wave velocity data corresponding to the sampling point; determining the shear wave velocity data body of the target layer segment according to the interpolated shear wave velocity data of all sampling points. The present application uses the four-component waveform data of the cross-dipole acoustic logging to calculate the dipole waveforms in several specified azimuths, uses the dispersion curve constrained inversion technology to calculate the radial shear wave velocity data in each azimuth, and uses the radial shear wave velocity data in multiple azimuths to perform interpolation and reconstruction to complete the rapid construction of the three-dimensional shear wave velocity body of the entire target layer segment; the method is simple and easy to implement, has a high actual processing efficiency, and is easy to promote and apply.

[0048] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by implementing the present application. Other advantages of the present application can be realized and obtained by the schemes described in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings are used to provide an understanding of the technical solution of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solution of the present application and do not constitute a limitation on the technical solution of the present application.

[0050] Figure 1 This is a flow chart of a method for constructing a formation shear wave velocity data volume according to an embodiment of the present application;

[0051] Figure 2 Schematic diagram of a device for constructing a formation shear wave velocity data volume according to an embodiment of the present application;

[0052] Figure 3 is a schematic diagram of a radial two-layer formation model in some exemplary embodiments;

[0053] Figure 4 is a schematic diagram of shear wave velocity distribution results at a depth point in some exemplary embodiments;

[0054] Figure 5 It is a schematic diagram of the radial shear wave velocity profile results of the change zone formation in some exemplary embodiments. DETAILED DESCRIPTION

[0055] The present application describes multiple embodiments, but the description is exemplary rather than restrictive, and it is obvious to those skilled in the art that there may be more embodiments and implementations within the scope of the embodiments described in the present application. Although many possible feature combinations are shown in the drawings and discussed in the specific embodiments, many other combinations of the disclosed features are also possible. Unless specifically limited, any feature or element of any embodiment may be used in combination with any other feature or element in any other embodiment, or may replace any other feature or element in any other embodiment.

[0056] The present application includes and contemplates combinations of features and elements known to those of ordinary skill in the art. The embodiments, features and elements disclosed in the present application may also be combined with any conventional features or elements to form a unique invention scheme defined by the claims. Any features or elements of any embodiment may also be combined with features or elements from other invention schemes to form another unique invention scheme defined by the claims. Therefore, it should be understood that any feature shown and / or discussed in the present application may be implemented individually or in any appropriate combination. Therefore, except for the limitations made according to the attached claims and their equivalents, the embodiments are not subject to other restrictions. In addition, various modifications and changes may be made within the scope of protection of the attached claims.

[0057] In addition, when describing representative embodiments, the specification may have presented the method and / or process as a specific sequence of steps. However, to the extent that the method or process does not rely on the specific order of the steps described herein, the method or process should not be limited to the steps of the specific order described. As will be understood by those of ordinary skill in the art, other sequences of steps are also possible. Therefore, the specific sequence of the steps set forth in the specification should not be interpreted as a limitation to the claims. In addition, the claims for the method and / or process should not be limited to the steps of performing them in the order written, and those skilled in the art can easily understand that these sequences can be changed and still remain within the spirit and scope of the embodiments of the present application.

[0058] The embodiment of the present invention provides a method for constructing a formation shear wave velocity data volume, such as Figure 1 As shown, the method includes steps S100-S110, which are specifically as follows:

[0059] Step S100: Perform the following operations for each sampling point in the four-component waveform data of the cross-dipole acoustic logging of the target layer:

[0060] The dipole waveforms at N directions are determined based on the four-component waveform data; the bending wave dispersion curve in the frequency domain of each direction is calculated based on the dipole waveforms at the N directions, and the shear wave velocity data of the corresponding direction is calculated using the dispersion curve constrained inversion technique; the shear wave velocity data at the N directions are interpolated to obtain the interpolated shear wave velocity data corresponding to the sampling point.

[0061] Step S110: Determine the shear wave velocity data volume of the target layer segment based on the interpolated shear wave velocity data of all sampling points.

[0062] In an exemplary embodiment, a multipole array acoustic logging instrument is used to measure the downhole target layer segment, collect four-component waveform data in the cross-dipole measurement mode, and preprocess the four-component waveform data; wherein the preprocessing operation includes: start time correction, waveform de-gaining and digital filtering, etc.

[0063] In an exemplary embodiment, N is a value determined by the well circumference and a preset interval angle, and N is an integer greater than 4. For example, within the range of 0-360° of the well circumference, with an interval of 15°, N is 24.

[0064] In an exemplary embodiment, determining dipole waveforms in N directions based on four-component waveform data includes: calculating the dipole waveforms in N directions respectively using a coordinate rotation equation based on the four-component waveform data; for example: calculating the dipole waveforms in 24 directions respectively at intervals of 15°.

[0065] The coordinate rotation equation is:

[0066] W(θ)=W XX cos 2 θ+(W XY +W YX )sinθcosθ+W YY sin 2 θ

[0067] Where W(θ) is the dipole waveform at the θ azimuth angle; θ is the azimuth angle; W XX is the four-component waveform data in the XX direction, W XY is the four-component waveform data in the XY direction, WYX The four-component waveform data in the Y and X directions, W YY They are four-component waveform data in the YY direction respectively.

[0068] For example: when the azimuth angle is 15°, W(15°) is the dipole waveform at the azimuth angle of 15°; when the azimuth angle is 45°, W(45°) is the dipole waveform at the azimuth angle of 45°.

[0069] In an exemplary embodiment, the bending wave dispersion curve in the frequency domain of each direction is calculated based on the dipole waveforms in N directions, including:

[0070] 1. Perform Fourier transform on the dipole waveform in each of the N directions to obtain the spectrum of the dipole waveform and the conjugate spectrum of the dipole waveform. Perform Fourier transform on the dipole waveform in each direction to obtain X n (ω) is the spectrum of the dipole waveform. The spectrum of the waveform can be obtained by Fourier transforming the dipole waveform in each direction. The spectrum is a complex number, and the conjugate spectrum of the dipole waveform can be obtained by taking the conjugate of the complex number.

[0071] Second, for each angular frequency value, the spectral coherence function is used according to the spectrum of the dipole waveform and the conjugate spectrum of the dipole waveform to determine the spectral coherence function value of the azimuthal dipole waveform under each set bending wave velocity value.

[0072] 3. The bending wave velocity corresponding to the maximum value of the spectrum coherence function is taken as the bending wave velocity at the angular frequency. The spectrum coherence function is:

[0073]

[0074] Where ρ(ω, V) is the value of the spectral coherence function; X m (ω) is the spectrum of the dipole waveform; is the conjugate spectrum of the dipole waveform; M is the number of receivers of the cross-dipole acoustic logging instrument, m represents the receiver number; V is the bending wave velocity; ω is the angular frequency; l is the distance between two adjacent receivers.

[0075] 4. Obtain the bending wave dispersion curve based on the bending wave velocity at each angular frequency. At each frequency point, a series of coherence function values ​​of the bending wave velocity are calculated. The bending wave velocity corresponding to the maximum value of the coherence function at that frequency is taken as the bending wave velocity at that frequency; the above processing is performed for each frequency within a given frequency range to obtain the bending wave dispersion curve. For example: for a dipole waveform, the weighted spectrum correlation analysis technique, i.e., the spectrum coherence function, is used in the frequency domain to calculate the bending wave dispersion curves at 24 directions respectively.

[0076] In an exemplary embodiment, based on the characteristics of the flexural wave dispersion curve and the theoretical dispersion curve, the radial shear wave velocity profile of the corresponding azimuth is calculated by using the dispersion curve constrained inversion technique: the first step is to calculate the radial shear wave velocity profile of the corresponding azimuth according to the flexural wave dispersion curve, the homogeneous formation dispersion curve V1(ω) and the theoretical dispersion curve V2(ω, d, V S1 ), establish the thickness and shear wave velocity inversion objective function of radially layered strata;

[0077] In this step, the dispersion curve V1(ω) of the homogeneous formation and the theoretical dispersion curve V2(ω, d, V s1 )as follows:

[0078] (1) The dispersion curve V1(ω) of a homogeneous formation is determined by the following steps:

[0079] Determine the wave number at different angular frequencies using a dispersion equation of multipole acoustic wave propagation in a homogeneous formation according to the wellbore radius, formation density, formation P-wave velocity, shear wave velocity of the change zone formation, wellbore fluid density and fluid velocity;

[0080] According to the wave numbers at different angular frequencies determined, the dispersion curve of the homogeneous formation under the corresponding homogeneous formation shear wave velocity is calculated. In this embodiment, the radial variation formation model is simplified to a radial double-layer model, such as Figure 3 The schematic diagram of the radial double-layer formation model shown in the figure shows that the radial thickness of the formation in the variable zone is d, the radius of the wellbore is a, and r is the radial distance between the formation and the wellbore.

[0081] In this simplified radial two-layer model, according to the shear wave velocity V S1 , the shear wave velocity of the original formation, using the borehole radius, formation density, formation P-wave velocity, shear wave velocity of the changing zone formation, wellbore fluid density and fluid velocity and other related parameters, into the dispersion equation of multipole acoustic wave propagation in the homogeneous formation, the shear wave velocity of the homogeneous formation is obtained as V S1 The dispersion curve V1(ω) when ;

[0082] The dispersion equation of multipole acoustic waves propagating in homogeneous formations is:

[0083] D(n, k, ω) = 0

[0084] Among them, n is the order of the sound source; k is the wave number; ω is the angular frequency.

[0085] By solving the wave number at different angular frequencies ω using the dispersion equation D, we can obtain the shear wave velocity V in the homogeneous formation. S1 The dispersion curve V1(ω) at .

[0086] The relevant parameters of the change zone formation (near wellbore formation) and the original formation are introduced into the dispersion equation of multipole acoustic wave propagation in radial layered formations to obtain the theoretical dispersion curve V2 (ω, d, V S1 );

[0087] Among them, the dispersion equation of radial layered stratum propagation is:

[0088] D1(n, k, ω)=0

[0089] By using the dispersion equation D1 and solving the wave number at different angular frequencies ω, the theoretical dispersion curve V2 (ω, d, V S1 ). Where n is the order of the sound source; k is the wave number; ω is the angular frequency.

[0090] The sound sources of currently commonly used acoustic logging instruments are mainly divided into monopole, dipole and quadrupole. Monopole sound source n = 0, dipole sound source n = 1, quadrupole sound source n = 2. The present invention is based on the measurement data of the dipole sound source, and n is 1.

[0091] The second step is to determine the minimum value of the inversion objective function using the least squares method within the preset variation zone stratum thickness and shear wave velocity parameter values, and use the shear wave velocity corresponding to the minimum value as the shear wave velocity of the variation zone stratum corresponding to the azimuth.

[0092] Among them, the inversion objective function of thickness and shear wave velocity of the variable zone strata in the radial layered stratum model is:

[0093]

[0094] In the formula, E(d, V S1 ) is the inversion residual of the objective function; d is the formation thickness of the variable zone; V(ω) is the flexural wave dispersion curve; V s1 is the shear wave velocity of the variable zone formation; V1(ω) is the dispersion curve of the homogeneous formation; V2(ω, d, V S1 ) is the theoretical dispersion curve; Ω is the preset inversion processing frequency band; Ω′ is the preset inversion constraint frequency band; λ is the weight factor.

[0095] In this step, the preset inversion processing frequency band is generally [2500Hz, 7500Hz]; the preset inversion constraint frequency band is the high-frequency constraint frequency band of inversion, which is generally [9000Hz, 10000Hz]; λ is the weight factor, which is generally 3 to 4.

[0096] In an exemplary embodiment, after the shear wave radial velocity data of the corresponding azimuth is calculated using the dispersion curve constrained inversion technique,

[0097] According to the shear wave velocity of the formation in the change zone and the shear wave velocity of the original formation, the shear wave velocity formula of the formation at different radial depths is used to determine the shear wave velocity of the formation at different radial depths in the azimuth;

[0098] According to the formation shear wave velocity of each azimuth variation zone, the formation shear wave velocity (V S (r,θ i )| i＝1～24 );

[0099] The formula for the shear wave velocity of the formation at different radial depths is:

[0100]

[0101] In the above formula, V S (r) is the shear wave velocity of the formation at different radial depths, V S2 is the original formation shear wave velocity, is the shear wave velocity of the formation in the variation zone obtained by inversion, a is the wellbore radius, and r is the radial distance from the wellbore wall.

[0102] In an exemplary embodiment, interpolating the N azimuth radial shear wave velocity data to obtain interpolated shear wave velocity data corresponding to the sampling point includes:

[0103] The first step is to establish a polar coordinate model of wellbore shear wave velocity, and to perform grid discretization processing in radial and circumferential directions under the polar coordinate model;

[0104] In this step, it is assumed that the wellbore is a regular cylinder with a radius of a. On the cross section of the wellbore, with the center of the circle as the coordinate origin, a polar coordinate model of the shear wave velocity of the formation near the wellbore is established.

[0105] The second step is to convert the discretized grid coordinates (r, θ) into the rectangular coordinate system (x, y);

[0106] The grid coordinates (r, θ) in the polar coordinate system are converted from the radial distance r and θ of the well wall to the rectangular coordinate system (x, y). The specific conversion relationship is:

[0107]

[0108] The third step is to use the interpolation algorithm to interpolate the formation shear wave velocity at N directions in the rectangular coordinate system to obtain the interpolated shear wave velocity data corresponding to the sampling point, such as Figure 4 Shown is a schematic diagram of the cross-sectional slice results of the three-dimensional shear wave velocity body of the formation near the wellbore, i.e., the changing zone, at a certain depth.

[0109] Wherein, the interpolation algorithm is:

[0110] Interpolate in the x direction:

[0111]

[0112] Interpolate in the y direction:

[0113]

[0114] In the above formula, x=r cosθ, y=r sinθ; (x1, y1) and (x2, y2) are the coordinate values ​​of two points respectively; and v is the shear wave velocity.

[0115] The shear wave velocity data are calculated at different depth points until the circumferential and radial shear wave velocity bodies of the formation (near the wellbore) in the entire depth target section are constructed, such as Figure 5 The following is a schematic diagram of the longitudinal slice results of the three-dimensional shear wave velocity body of the change zone at different orientations. Figure 4 and Figure 5 It can be seen that the three-dimensional shear wave velocity body constructed in this embodiment can effectively reflect the spatial distribution of shear wave velocity near the wellbore. In addition, by combining the azimuth shear wave radial velocity profile inversion and spatial interpolation reconstruction technology, the efficiency of constructing the three-dimensional formation shear wave velocity data body can be significantly improved.

[0116] The disclosed embodiment also provides a device for constructing a formation shear wave velocity data body, such as Figure 2 As shown, the device includes: a memory 200 and a processor 210; the memory is used to store a program for constructing a formation shear wave velocity data body, and the processor is used to read and execute the program for constructing a formation shear wave velocity data body, and execute any one of the methods described in the above embodiments.

[0117] The present disclosure also provides a computer-readable storage medium having a data processing program stored thereon. The data processing program is executed by a processor to implement the method for constructing a formation shear wave velocity data volume described in any one of the above embodiments.

[0118] Example 1

[0119] This example shows the construction process of the formation shear wave velocity data volume as follows:

[0120] 1) Using a multipole array acoustic logging instrument to measure the downhole target layer, collecting four-component waveform data in a cross-dipole measurement mode, and preprocessing the four-component waveform data;

[0121] 2) In the range of 0-360° around the well, at intervals of 15°, the dipole waveforms at 24 directions are calculated using the four-component waveform data measured in the cross-dipole mode;

[0122] 3) Using the weighted spectrum correlation analysis technique in the frequency domain, the flexural wave dispersion curves in 24 directions are calculated for the dipole waveform;

[0123] 4) Based on the actual and theoretical dispersion curves of flexural waves, the radial shear wave velocity profiles at the corresponding azimuths are calculated using the dispersion curve constraint inversion technique.

[0124] 5) Establish a polar coordinate model of shear wave velocity near the wellbore, discretize the model in radial and circumferential directions, and reconstruct the shear wave velocity at different radial and circumferential positions by interpolation of shear wave velocities at different radial depths in 24 directions;

[0125] 6) Repeat steps 2-6 at different depths until the entire depth interval is processed, thereby realizing the construction of a three-dimensional shear wave velocity body of the formation near the wellbore.

[0126] The present invention proposes a method for rapidly constructing a near-wellbore three-dimensional formation shear wave velocity data body. The four-component waveform data obtained by the array acoustic logging cross-dipole measurement mode is used to calculate the dipole waveforms of several specified azimuths, and the dispersion curve constrained inversion technology is used to calculate the shear wave radial velocity profile of each azimuth. The shear wave radial velocity profiles of multiple azimuths are interpolated and reconstructed to complete the rapid construction of the three-dimensional shear wave velocity body of the entire target layer. The method is simple and easy to implement, has a high actual processing efficiency, and is easy to promote and apply.

[0127] It will be appreciated by those skilled in the art that all or some of the steps, systems, and functional modules / units in the methods disclosed above may be implemented as software, firmware, hardware, and appropriate combinations thereof. In hardware implementations, the division between the functional modules / units mentioned in the above description does not necessarily correspond to the division of physical components; for example, a physical component may have multiple functions, or a function or step may be performed by several physical components in cooperation. Some or all components may be implemented as software executed by a processor, such as a digital signal processor or a microprocessor, or implemented as hardware, or implemented as an integrated circuit, such as an application-specific integrated circuit. Such software may be distributed on a computer-readable medium, which may include a computer storage medium (or non-transitory medium) and a communication medium (or temporary medium). As known to those skilled in the art, the term computer storage medium includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store the desired information and can be accessed by a computer. In addition, it is well known to those of ordinary skill in the art that communication media typically contain computer-readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism, and may include any information delivery media.

Claims

1. A method for constructing a formation shear wave velocity data volume, characterized in that: The method comprises: The following operations are performed for each sampling point in the four-component waveform data of the cross-dipole acoustic logging of the target layer: Determine the dipole waveforms at N directions according to the four-component waveform data; calculate the bending wave dispersion curve in the frequency domain of each direction according to the dipole waveforms at the N directions, and calculate the shear wave velocity data of the corresponding direction using the dispersion curve constrained inversion technology; interpolate the shear wave velocity data at the N directions to obtain the interpolated shear wave velocity data corresponding to the sampling point; wherein N is an integer greater than 4; The shear wave velocity data volume of the target layer segment is determined according to the shear wave velocity data after interpolation of all sampling points.

2. The method for constructing a formation shear wave velocity data volume according to claim 1, characterized in that: The method further comprises: Performing relevant preprocessing operations on the four-component waveform data of the cross-dipole acoustic logging of the target layer; Wherein, the preprocessing operation includes one or more of the following: start time correction, waveform gain reduction and digital filtering.

3. The method for constructing a formation shear wave velocity data volume according to claim 1, characterized in that: The method of determining the dipole waveforms in N directions according to the four-component waveform data includes: According to the four-component waveform data, the dipole waveforms in N directions are calculated respectively using the coordinate rotation equation, wherein the coordinate rotation equation is: W(θ)=W XX cos 2 θ+(W XY +W YX )sinθcosθ+W YY sin 2 i Where W(θ) is the dipole waveform at the θ azimuth angle; θ is the azimuth angle; W XX is the four-component waveform data in the XX direction, W XY is the four-component waveform data in the XY direction, W YX is the four-component waveform data in the YX direction, W YY They are four-component waveform data in the YY direction respectively.

4. The method for constructing a formation shear wave velocity data volume according to claim 1, characterized in that: The step of calculating the bending wave dispersion curve in the frequency domain at each orientation according to the dipole waveforms at the N orientations comprises: Performing Fourier transformation on the dipole waveform in each of the N directions to obtain a spectrum of the dipole waveform and a conjugate spectrum of the dipole waveform; For each angular frequency value, using a spectral coherence function according to the spectrum of the dipole waveform and the conjugate spectrum of the dipole waveform, respectively determine the spectral coherence function values ​​of the azimuthal dipole waveform under each set bending wave velocity value, and use the bending wave velocity corresponding to the maximum value of the spectral coherence function as the bending wave velocity at the angular frequency; The bending wave dispersion curve is obtained according to the bending wave velocity at each angular frequency.

5. The method for constructing a formation shear wave velocity data volume according to claim 4, characterized in that: The spectral coherence function is: Where ρ(ω, V) is the value of the spectral coherence function; X m (ω) is the spectrum of the dipole waveform; is the conjugate spectrum of the dipole waveform; M is the number of receivers of the cross-dipole acoustic logging instrument, m represents the receiver number; V is the bending wave velocity; ω is the angular frequency; l is the distance between two adjacent receivers.

6. The method for constructing a formation shear wave velocity data volume according to claim 4, characterized in that: The method of calculating the shear wave velocity data of the corresponding azimuth using the dispersion curve constraint inversion technique includes: According to the bending wave dispersion curve, the homogeneous formation dispersion curve and the theoretical dispersion curve at each of the N directions, an inversion objective function of the thickness and shear wave velocity of the variable zone formation in the radial layered formation model is established; The minimum value of the inversion objective function is determined by the least square method within the preset variation zone formation thickness and shear wave velocity parameter values, and the shear wave velocity corresponding to the minimum value is used as the shear wave velocity of the variation zone formation corresponding to the azimuth.

7. The method for constructing a formation shear wave velocity data volume according to claim 6, characterized in that: The dispersion curve of the homogeneous formation is determined by the following steps: Determine the wave number at different angular frequencies using a dispersion equation of multipole acoustic wave propagation in a homogeneous formation according to the wellbore radius, formation density, formation P-wave velocity, shear wave velocity of the change zone formation, wellbore fluid density and fluid velocity; According to the determined wave numbers at different angular frequencies, the dispersion curve of the homogeneous formation at the corresponding shear wave velocity of the homogeneous formation is calculated.

8. The method for constructing a formation shear wave velocity data volume according to claim 6, characterized in that: The objective function of thickness and shear wave velocity inversion of the variable zone strata in the radially layered stratum model is: In the formula, E(d, V S1 ) is the inversion residual of the objective function; d is the formation thickness of the variation zone; V(ω) is the flexural wave dispersion curve; V s1 is the shear wave velocity of the variable zone formation; V1(ω) is the dispersion curve of the homogeneous formation; V2(ω, d, V S1 ) is the theoretical dispersion curve; Ω is the preset inversion processing frequency band; Ω′ is the preset inversion constraint frequency band; λ is the weight factor.

9. The method for constructing a formation shear wave velocity data volume according to claim 7, characterized in that: After the dispersion curve constrained inversion technique is used to calculate the shear wave velocity of the formation in the corresponding azimuth variation zone, the method further comprises: According to the shear wave velocity of the formation in the change zone and the shear wave velocity of the original formation, the shear wave velocity formula of the formation at different radial depths is used to determine the shear wave velocity of the formation at different radial depths in the azimuth; Determine the formation shear wave velocity at different radial depths in N directions according to the formation shear wave velocity of the variation zone in each direction; The formula for the shear wave velocity of the formation at different radial depths is: In the above formula, V S (r) is the shear wave velocity of the formation at different radial depths; V S2 is the shear wave velocity of the original formation; is the shear wave velocity of the formation in the variation zone obtained by inversion; a is the wellbore radius; r is the radial distance from the wellbore wall.

10. The method for constructing a formation shear wave velocity data volume according to claim 9, characterized in that: The interpolating the N azimuth radial shear wave velocity data to obtain the interpolated shear wave velocity data corresponding to the sampling point includes: Establishing a wellbore shear wave velocity polar coordinate model, and performing radial and circumferential mesh discretization processing under the polar coordinate model; Convert the discretized grid coordinates into a rectangular coordinate system; In the rectangular coordinate system, the interpolation algorithm is used to interpolate the formation shear wave velocity at N directions to obtain the interpolated shear wave velocity data corresponding to the sampling point; Wherein, the interpolation algorithm is: Interpolate in the x direction: Interpolate in the y direction: In the above formula, x=r cosθ, y=r sinθ; (x1, y1) and (x2, y2) are the coordinate values ​​of two points respectively; and v is the shear wave velocity.

11. A device for constructing a formation shear wave velocity data volume, characterized in that: The device comprises: a memory and a processor; the memory is used to store a program for constructing a formation shear wave velocity data body, and the processor is used to read and execute the program for constructing a formation shear wave velocity data body, and execute the method described in any one of claims 1-10.

12. A computer-readable storage medium having a data processing program stored thereon, wherein the data processing program is executed by a processor to construct the method for constructing a formation shear wave velocity data volume according to any one of claims 1 to 10.

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