WO2024093855A1 - Shear wave splitting correction method, system, storage medium and electronic device - Google Patents

Abstract

The present invention relates to the technical field of seismic data processing; provided are a shear wave splitting correction method, a system, a storage medium, and an electronic device. The method comprises: acquiring shear wave data, performing fast and slow wave separation on the shear wave data to obtain fast shear wave data and slow shear wave data, and performing post-stack processing on the fast shear wave data and the slow shear wave data to obtain post-stack fast shear wave data and post-stack slow shear wave data; calculating time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data using a dynamic time adjustment algorithm; and performing shear wave data correction on the basis of the time difference data. The present method prevents shortcomings such as the shear wave correction process of manual picking of fast shear wave layer positions and corresponding slow shear wave layer positions being time-consuming and laborious, and there being picking errors, and a cross-correlation method having low time window length selection and calculation efficiency, and large result errors being.

Description

A shear wave splitting correction method, system, storage medium and electronic device Technical Field

The present invention relates to the technical field of seismic data processing, and in particular to a shear wave splitting correction method, a shear wave splitting correction system, a computer-readable storage medium and an electronic device.

Background technique

Seismic exploration refers to the geophysical exploration method of artificially stimulating and receiving seismic waves, observing and analyzing the propagation law of seismic waves underground, and inferring the properties and morphology of underground rock formations. It plays a key role in oil and gas, coalfield and engineering geological exploration, as well as the detection of deep structures in the crust and upper mantle. The seismic waves stimulated and received in seismic exploration can be longitudinal waves or transverse waves.

In the upper part of the earth's crust, directional fractures filled with fluids are widely distributed. In many oil and gas fields, the flow of fluids is often controlled by fractures. Therefore, the study of fractured oil and gas reservoirs is of great significance. In the area of directional vertical (quasi-vertical) fractures, when the shear wave passes through the fracture, it is split into a fast shear wave polarized along the direction of the fracture and a slow shear wave polarized perpendicular to the direction of the fracture. The waveforms of the fast and slow shear waves are similar, but the propagation speeds of the fast and slow shear waves are different, resulting in different travel times. The fast and slow shear waves are recorded by the two horizontal components of the detector. By analyzing the amplitude and travel time of the fast and slow shear waves, the direction of the fracture, relative density and other parameters can be determined.

In the presence of multi-layer fractured media (fracture direction does not change with depth), the existing shear wave splitting correction method mainly calculates the time difference between fast and slow shear waves through the manual layer picking method and the cross-correlation method. Manually picking fast and slow shear waves of multiple marker layers is time-consuming and laborious, and there are picking errors; the cross-correlation method has problems such as time window length selection, slow calculation efficiency, and large result errors.

Summary of the invention

The purpose of the embodiments of the present invention is to provide a shear wave splitting correction method, a shear wave splitting correction system, a computer-readable storage medium and an electronic device, so as to at least solve the problems existing in the prior art in the process of realizing shear wave splitting correction, such as being time-consuming and labor-intensive, having low computational efficiency and having large result errors.

In order to achieve the above object, the present invention provides a shear wave splitting correction method in a first aspect, comprising:

The time difference data between post-stack fast shear wave data and post-stack slow shear wave data are calculated using a dynamic time adjustment algorithm;

Performing shear wave data correction based on the time difference data includes:

Correcting the prestack slow shear wave data based on the time difference data;

The Alford rotation formula is used to process the prestack fast shear wave data and the prestack slow shear wave data after time difference correction to obtain the corrected shear wave data.

The method uses a dynamic time adjustment algorithm to calculate the time difference between fast shear waves and slow shear waves. The calculation process is fast, the calculation result is accurate, and manpower and material resources are saved.

Optionally, before calculating the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data using the dynamic time adjustment algorithm, the method further includes:

Acquire shear wave data, perform fast and slow wave separation on the shear wave data to obtain fast shear wave data and slow shear wave data, perform post-stack processing on the fast shear wave data and the slow shear wave data to obtain post-stack fast shear wave data and post-stack slow shear wave data. Based on the post-stack fast shear wave data and the post-stack slow shear wave data, the time difference for correcting the shear wave data can be calculated.

Optionally, the post-stack processing uses overlay processing or offset processing.

Optionally, the Alford rotation formula is used to achieve fast and slow wave separation of shear wave data.

A second aspect of the present invention provides a shear wave splitting correction system, comprising:

A time difference calculation module is used to calculate the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data;

A correction module, which corrects the shear wave data based on the time difference data calculated by the time difference calculation module;

The correcting of the shear wave data based on the time difference data calculated by the time difference calculation module comprises:

Correct prestack slow shear wave data based on time difference data;

The Alford rotation formula is used to process the prestack fast shear wave data and the corrected prestack slow shear wave data to obtain the corrected shear wave data.

Optionally, also include:

An acquisition module, used for acquiring shear wave data;

A separation module is used to separate the acquired shear wave data into fast and slow waves;

The post-stack processing module is used to perform post-stack processing on fast shear wave data and slow shear wave data.

Optionally, the post-stack processing uses overlay processing or offset processing.

The third aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, so that when the computer instructions are executed on a computer, the first aspect of the present invention is executed. The method described.

A fourth aspect of the present invention provides an electronic device, comprising: at least one processor and a memory;

The memory stores computer-executable instructions;

The at least one processor executes the computer-executable instructions stored in the memory, so that the electronic device performs the method described in the first aspect.

Through the above technical scheme, the present invention avoids the time-consuming and labor-intensive manual picking of fast shear wave layers and corresponding slow shear wave layers and the picking errors during the shear wave correction process, as well as the shortcomings of the cross-correlation method such as time window selection, slow calculation efficiency, and large result errors.

Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide a further understanding of the embodiments of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the embodiments of the present invention, but do not constitute a limitation on the embodiments of the present invention. In the accompanying drawings:

FIG1 is a flow chart of a shear wave splitting correction method provided by one embodiment of the present invention;

FIG2 is a schematic diagram of four-component data in a shot detection direction and a tangential direction of the shot detection direction provided by an embodiment of the present invention;

FIG3 is a schematic diagram of fast and slow shear wave data of four components provided by an embodiment of the present invention;

4 is a schematic diagram of post-stack fast shear wave data and post-stack slow shear wave data provided by an embodiment of the present invention, wherein the left side of the figure shows the post-stack fast shear wave data, and the right side of the figure shows the post-stack slow shear wave data;

FIG5 is time difference data provided by an embodiment of the present invention;

FIG6 is a schematic diagram of two-component slow shear wave data after time difference correction provided by an embodiment of the present invention;

FIG. 7 is a schematic diagram of four-component data in the shot detection direction and the shot detection tangent direction after time difference correction provided by an embodiment of the present invention.

Detailed ways

The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present invention, and is not used to limit the present invention.

The steps of shear wave splitting correction in the prior art are: assuming that the splitting has been obtained through shear wave splitting analysis The direction of the seam is determined by using the Alford formula to separate the fast and slow waves of the shear wave data, and the fast and slow shear wave sections are obtained. The time difference between the fast and slow shear waves is calculated, and then the slow wave data is corrected to the time of the fast wave data. Among the current methods for calculating the time difference between fast and slow shear waves, the manual picking method is to manually pick the fast shear wave layer and the corresponding slow shear wave layer, and then correct the slow wave data to the fast wave data time by block interpolation. This method requires manual picking, and the whole process is time-consuming and labor-intensive, and there are picking errors. The cross-correlation method has problems such as time window length selection, slow calculation efficiency, and large result errors.

FIG1 is a flow chart of a shear wave splitting method provided by an embodiment of the present invention. As shown in FIG1 , an embodiment of the present invention provides a shear wave splitting method, the method comprising:

S1: Obtain shear wave data, and use the Alford formula to separate the fast and slow waves of the shear wave data to obtain fast shear wave data and slow shear wave data.

S2: Perform post-stack processing on the fast shear wave data and the slow shear wave data to obtain post-stack fast shear wave data and post-stack slow shear wave data. Post-stack processing can be achieved by stacking or migration.

S3: Based on the post-stack fast shear wave data and the post-stack slow shear wave data obtained by post-stack processing, a dynamic time adjustment algorithm is used to perform time difference calculation to obtain time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data.

S4: performing time difference correction on the pre-stack slow shear wave data using the calculated time difference data to obtain the pre-stack slow shear wave data after time difference correction.

S5: Using the Alford formula, the prestack fast shear wave data and the corrected prestack slow shear wave data are rotated to obtain shear wave data, thus completing the split correction of the shear wave data.

During the calculation process, this method uses a dynamic time adjustment algorithm to calculate the time difference between fast shear waves and slow shear waves. The calculation process is fast and the calculation results are accurate, which saves the time of manual picking and avoids the errors introduced by manual picking. It has great application prospects in shear wave seismic processing.

A specific implementation example is given below:

In this method, there is a step of performing post-stack processing on fast shear wave data and slow shear wave data, so for the convenience of description, the data that have not been post-stack processed are called pre-stack data, and the data that have been post-stack processed are called post-stack data.

Step 1: For the convenience of representation, the shear wave data obtained in this embodiment is represented in the form of four components _: ( _{SXRX , SXRY , SYRX} , SYRY); first, the shear wave data ( _{SXRX , SXRY , SYRX , SYRY} ) are rotated using the Alford formula to obtain four-component data in the shot detection (shot point-detection _point ) direction and _in the tangent direction of the shot detection direction _. ( _SRRR , _{SRRT , STRRR , STRRT} ), as shown in _Figure 2; the calculation formula _is as follows:

θ＝θ _Azimuth -θ _Inline ； (2)

Wherein, S _X R _X is the shear wave data component excited by the seismic source in the x direction and received by the geophone in the x direction; S _X R _Y is the shear wave data component excited by the seismic source in the x direction and received by the geophone in the y direction; S _Y R _X is the shear wave data component excited by the seismic source in the y direction and received by the geophone in the x direction; S _Y R _Y is the shear wave data component excited by the seismic source in the y direction and received by the geophone in the y direction; S _R R _R is the shear wave data component excited by the seismic source in _{the shot detection direction and received by the geophone in the tangential direction of the shot detection direction; S T R R is the shear} wave data component excited by the seismic source in the tangential direction of the shot detection direction and received by the geophone in the shot detection direction; S _T R _T is the shear wave data component excited by the seismic source in the tangential direction of the shot detection direction and received by the geophone in the tangential direction of the shot detection direction; θ is the angle between the survey line direction of the data and the shot detection line; θ _Azimuth is the angle corresponding to the direction of the gun-detection line; θ _Inline is the angle corresponding to the direction of the survey line.

Then _, the Alford rotation formula is used to rotate the four-component data in the shot detection direction and the tangential direction of the shot detection direction ( _SRRR , _{SRRT , STRRR , STRRT} ) to obtain the prestack fast _shear wave data ( _{SS1RS1 )} and prestack slow _{shear wave data (SS2RS2 )} , as shown in Figure 3.

S _S1 R _S1 represents prestack fast shear wave data, S _S1 R _S2 represents the projection of prestack fast shear wave on prestack slow shear wave, S _S2 R _S1 represents the projection of prestack slow shear wave on prestack fast shear wave, and S _S2 R _S2 represents prestack slow shear wave data; (S _S1 R _S1 , S _S2 R _S1 ) represents prestack fast shear wave component data, (S _S1 R _S2 , S _S2 R _S2 ) represents prestack slow shear wave component data; is the angle between the crack direction and the direction of the gun-detection line; θ _Fracture is the angle corresponding to the crack direction; θ _Azimuth is the angle corresponding to the direction of the gun-detection line.

Step 2: Perform post-stack processing on the pre-stack fast shear wave data (S _S1 R _S1 ) and the pre-stack slow shear wave data (S _S2 R _S2 ) to obtain post-stack fast shear wave data and post-stack slow shear wave data, as shown in Figure 4. Post-stack processing can be achieved by stacking or migration.

Step 3: Based on the post-stack fast shear wave data and the post-stack slow shear wave data obtained by post-stack processing, the time difference is calculated using the dynamic time adjustment algorithm to obtain the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data, as shown in FIG5 .

Step 4: Use the calculated time difference data to perform time difference correction on the prestack slow shear wave component data (S _S1 R _S2 , S _S2 R _S2 ) in equation (3) to obtain the prestack slow shear wave component data after time difference correction (S′ _S1 R′ _S2 , S′ _S2 R′ _S2 ), as shown in Figure 6.

Step 5: Using the Alford formula, the prestack fast shear wave component data ( _SS1RS1 , _SS2RS1 ) and the corrected prestack slow shear wave component data ( _S′S1R′S2 , _S′S2R′S2 ) are rotated to obtain four-component data in the shot inspection direction and its tangential direction ( _{S′RR′R , S′RR′T , S′TR′R , S′TR′T} ), as shown in Figure 7, i.e., the shear wave data after shear wave splitting _correction , _thus completing _{the shear wave} data splitting correction.

Among them, S′ _R R′ _R is the corrected shear wave data component excited by the seismic source in the shot detection direction and received by the geophone in the shot detection direction; S′ _R R′ _T is the corrected shear wave data component excited by the seismic source in the shot detection direction and received by the geophone in the tangential direction of the shot detection direction; S′ _T R′ _R is the corrected shear wave data component excited by the seismic source in the tangential direction of the shot detection direction and received by the geophone in the shot detection direction; S′ _T R′ _T is the corrected shear wave data component excited by the seismic source in the tangential direction of the shot detection direction and received by the geophone in the tangential direction of the shot detection direction.

The dynamic time adjustment algorithm used in step 3 is also called the dynamic time warping (DTW) algorithm. The algorithm calculates the alignment error between the two signals, adds the alignment errors to obtain the cumulative distance, and then traces back in the cumulative distance to obtain the time delay (time difference) between the two signals.

The principle of dynamic time adjustment algorithm is as follows:

For the time series f[i], a time-varying delay (time shift) u[i] is performed to obtain a new time series g[i], which can be expressed as:
g[i]＝f[i+u[i]] (7)

Dynamic time adjustment is to find the time-varying delay u[0:N-1]≡(u[0],u[1],...,u[N-1]), that is, to solve the following optimization problem,

in,

D in formula (9) is usually called distance. The constraint condition is,
|u[i]-u[i-1]|≤1 (10)

Dynamic time adjustment will produce a minimum delay sequence approximately equal to u[i]. In practical applications, sometimes the restrictions of formula (10) are not very reasonable, so the accuracy of the delay obtained is low. When the restriction condition becomes,

Then the corresponding cumulative distance d[i,l] is calculated as follows:

To find the delay u[i], three steps need to be performed in the dynamic time adjustment method:

(1) Calculate alignment error

The first step is to define the alignment error between time series f[i] and g[i],
e[i,l]＝(f[i]-g[i+l]) ² (13)

Where l is the sample delay. If l is approximately equal to u[i], the error e[i,l] approaches zero.

(2) Cumulative distance

The second step is to iteratively calculate the error e[i,l] to obtain the cumulative distance d[i,l]. The calculation formula is as follows:

Constraint (10) indicates that when calculating formula (8), we only need to calculate d[i-1,l-1], d[i-1,l] and d[i-1,l+1].

(3) Reverse tracking

The third step is to trace back in the distance d[i,l] to find the minimum path, that is, the sequence u[0:N-1]. The first delay at the beginning of the trace is u[N-1], and the last delay is u[0].

(4) Delay Application

After calculating the time delay, the new time series f ¹ [i] is obtained using formula (7).

The embodiment of the present invention further provides a shear wave splitting correction system, comprising:

An acquisition module, used for acquiring shear wave data;

A separation module, used for separating the acquired shear wave data into fast waves and slow waves;

The post-stack processing module is used to perform post-stack processing on fast shear wave data and slow shear wave data.

A time difference calculation module is used to calculate the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data;

The correction module corrects the shear wave data based on the time difference data calculated by the time difference calculation module.

An embodiment of the present invention further provides a computer-readable storage medium, on which computer instructions are stored, so that when the computer instructions are run on a computer, a shear wave splitting correction method provided in this embodiment is executed.

A fourth aspect of the present invention provides an electronic device, comprising: at least one processor and a memory;

The memory stores computer-executable instructions;

The at least one processor executes the computer-executable instructions stored in the memory, so that the electronic device executes a shear wave splitting correction method provided in this embodiment.

Those skilled in the art will understand that all or part of the steps in the method for implementing the above-mentioned embodiments can be completed by instructing the relevant hardware through a program, and the program is stored in a storage medium, including several instructions for making a single-chip microcomputer, chip or processor execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: a USB flash drive, a mobile hard disk, a read-only storage device, a memory card ... Various media that can store program codes include ROM (Read-Only Memory), RAM (Random Access Memory), disks or optical disks.

The optional embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the embodiments of the present invention are not limited to the specific details in the above embodiments. Within the technical concept of the embodiments of the present invention, the technical scheme of the embodiments of the present invention can be subjected to a variety of simple modifications, and these simple modifications all belong to the protection scope of the embodiments of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the embodiments of the present invention will not further describe various possible combinations.

In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the embodiments of the present invention, they should also be regarded as the contents disclosed in the embodiments of the present invention.

Claims (9)

1. A shear wave splitting correction method, characterized by comprising:

   The time difference data between post-stack fast shear wave data and post-stack slow shear wave data are calculated using a dynamic time adjustment algorithm;

   Performing shear wave data correction based on the time difference data includes:

   Correcting prestack slow shear wave data based on the time difference data;

   The Alford rotation formula is used to process the prestack fast shear wave data and the corrected prestack slow shear wave data to obtain the corrected shear wave data.
2. The shear wave splitting correction method according to claim 1 is characterized in that before using the dynamic time adjustment algorithm to calculate the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data, it also includes:

   Acquire shear wave data, perform fast-wave and slow-wave separation on the shear wave data to obtain fast shear wave data and slow shear wave data, and perform post-stack processing on the fast shear wave data and the slow shear wave data to obtain post-stack fast shear wave data and post-stack slow shear wave data.
3. The shear wave splitting correction method according to claim 2 is characterized in that the post-stack processing uses stacking processing or offset processing.
4. The shear wave splitting correction method according to claim 1 is characterized in that the fast and slow wave separation of shear wave data is achieved using the Alford rotation formula.
5. A shear wave splitting correction system, characterized by comprising:

   A time difference calculation module is used to calculate the time difference data between the post-stack fast shear wave data and the post-stack slow shear wave data;

   A correction module, which corrects the shear wave data based on the time difference data calculated by the time difference calculation module;

   The correcting of the shear wave data based on the time difference data calculated by the time difference calculation module comprises:

   Correct prestack slow shear wave data based on time difference data;

   The Alford rotation formula is used to process the prestack fast shear wave data and the corrected prestack slow shear wave data to obtain the corrected shear wave data.
6. The shear wave splitting correction system according to claim 5, characterized in that it also includes:

   An acquisition module, used for acquiring shear wave data;

   A separation module is used to separate the acquired shear wave data into fast and slow waves;

   The post-stack processing module is used to perform post-stack processing on fast shear wave data and slow shear wave data.
7. The shear wave splitting correction system according to claim 6 is characterized in that the post-stack processing uses stacking processing or offset processing.
8. A computer-readable storage medium, characterized in that computer instructions are stored on the computer-readable storage medium, so that when the computer instructions are run on a computer, the method according to any one of claims 1 to 4 is executed.
9. An electronic device, characterized in that it comprises: at least one processor and a memory;

   The memory stores computer-executable instructions;

   The at least one processor executes the computer-executable instructions stored in the memory, so that the electronic device performs the method according to any one of claims 1 to 4.