CN113391348B - Common reflection point gather construction method and device for prestack inversion - Google Patents
Common reflection point gather construction method and device for prestack inversion Download PDFInfo
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Abstract
The application provides a method and a device for constructing a common reflection point gather for prestack inversion, wherein the method comprises the following steps: performing OVT gather extraction on the common reflection point CMP gather in the original seismic data to generate offset vector sheet OVT gather; performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets; pre-stack denoising is carried out on the OVG gather; and carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion. The method can construct the common reflection point gather for pre-stack inversion, has high precision and can meet the requirement of pre-stack inversion.
Description
Technical Field
The application relates to the technical field of seismic data processing, in particular to a method and a device for constructing a common reflection point gather for prestack inversion.
Background
In an isotropic medium, when a plane longitudinal wave is obliquely incident to the interface of two media and the incident angle is relatively large, 4 waves, i.e., a reflected longitudinal wave, a reflected transverse wave, a transmitted longitudinal wave, and a transmitted transverse wave, are generated. Under the condition of a longitudinal wave source, transverse wave data can be obtained, which is the theoretical basis for carrying out pre-stack inversion by utilizing the incidence angle gathers of seismic data. The CRP gather (common reflection point gather) generated by using the conventional prestack time migration can invert the longitudinal wave impedance and the transverse wave impedance simultaneously on the basis of a horizontal lamellar earth model. Based on Bayesian theory, the pre-stack elastic parameter simultaneous inversion assumes that the seismic noise and the elastic model are gaussian probability distribution, and on the basis of maximum similarity, the low-frequency model established through geological data and logging data is optimally matched with a plurality of angle gather seismic data obtained through CRP gathers. The success or failure of pre-stack inversion has a great relation with AVO characteristics of the CRP gather, and when the AVO (Amplitude variation with offset, the change of amplitude along with offset) characteristics are correct, the CRP gather data can only reflect the actual geological characteristics of the underground.
Due to the design of an original observation system, the conventional prestack time migration has the characteristics of 'spindle-shaped' amplitude distribution, which is characterized by weak near offset and far offset amplitude and strong medium offset amplitude, of CRP gathers obtained by prestack time migration, and the amplitude distribution is characterized by being inconsistent with the AVO characteristics of a reservoir. In the prior art, residual amplitude compensation is typically performed on the CRP gather prior to pre-stack elastic impedance inversion to account for the "spindle-shaped" amplitude distribution characteristics of conventional pre-stack time-shifted CRP gathers. However, the residual amplitude compensation technique is a statistical technique, which extracts the amplitude compensation factors in a three-dimensional space, so that three-dimensional space data volumes with different attributes and three-dimensional space data volumes with different sizes have great influence on the amplitude compensation factors, the amplitude compensation factors obtained by statistics of the data volumes with different sizes are actually the amplitude compensation factors obtained by the sizes of the different geologic volumes, and how to define the data with the three-dimensional space to obtain the amplitude compensation factors is a preservation method, so that the standard is difficult to grasp. Therefore, the CRP gather precision of the conventional prestack time migration is low, and the requirement of prestack inversion cannot be met.
Disclosure of Invention
The embodiment of the application provides a method for constructing a common reflection point gather for prestack inversion, which is used for constructing the common reflection point gather for prestack inversion, has high precision and can meet the requirement of prestack inversion, and the method comprises the following steps:
performing OVT gather extraction on the common reflection point CMP gather in the original seismic data to generate offset vector sheet OVT gather;
performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets;
pre-stack denoising is carried out on the OVG gather;
and carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion.
The embodiment of the application provides a common reflection point gather construction device for prestack inversion, which is used for constructing the common reflection point gather for prestack inversion, has high precision and can meet the requirement of prestack inversion, and the device comprises:
the OVT gather generation module is used for carrying out OVT gather extraction on the common reflection point CMP gather in the original seismic data to generate offset vector chip OVT gathers;
the pre-stack time migration module is used for performing pre-stack time migration on the OVT gather to generate a OVG gather, and the OVG gather comprises a plurality of pre-stack time migration OVT sheets;
the denoising processing module is used for carrying out prestack denoising processing on the OVG gather;
and the CRP gather acquisition module is used for carrying out data regularization processing on the OVG gather subjected to pre-stack denoising processing to obtain a common reflection point CRP gather, wherein the CRP gather is used for pre-stack inversion.
The embodiment of the application also provides computer equipment, which comprises a memory, a processor and a computer program stored on the memory and capable of running on the processor, wherein the processor realizes the method for constructing the common reflection point gather for pre-stack inversion when executing the computer program.
The embodiment of the application also provides a computer readable storage medium, which stores a computer program for executing the common reflection point gather construction method for prestack inversion.
In the embodiment of the application, OVT gather extraction is carried out on common reflection point CMP gathers in original seismic data, and offset vector chip OVT gathers are generated; performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets; pre-stack denoising is carried out on the OVG gather; and carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion. Because the amplitudes of the near offset and the far offset of the CRP gather obtained by the conventional prestack time migration are weak, the amplitude of the middle offset is strong, and the requirement of prestack reservoir inversion cannot be met. The OVG gather generated by the embodiment of the application has balanced overall energy, and can meet the requirement of pre-stack inversion; after that, the OVG gather is subjected to pre-stack denoising treatment, so that the signal to noise ratio of the OVG gather is improved, the influence of random noise on the amplitude is eliminated, and the precision of the finally obtained CRP gather is improved.
Drawings
In order to more clearly illustrate the embodiments of the application or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art. In the drawings:
FIG. 1 is a flow chart of a method for constructing a common reflection point gather for pre-stack inversion in an embodiment of the application;
FIG. 2 is a schematic diagram of OVT data volume extraction according to an embodiment of the present application;
FIG. 3 is a detailed flowchart of a method for constructing a common reflection point gather for pre-stack inversion according to an embodiment of the present application;
FIG. 4 is a schematic diagram of a CRP gather obtained using a conventional prestack time shift;
FIG. 5 is a schematic representation of a OVG gather obtained by the method of the present application;
FIG. 6 is a schematic diagram of OVG trace set prior to pre-stack denoising;
FIG. 7 is a schematic diagram of a OVG gather after pre-stack denoising;
FIG. 8 is a schematic diagram of a superimposed cross-section of OVG gather prior to pre-stack denoising;
FIG. 9 is a schematic diagram of a superimposed cross-section of OVG gather after a pre-stack denoising process;
FIG. 10 is a schematic diagram of the amplitude attribute of OVG gather prior to pre-stack denoising;
FIG. 11 is a schematic illustration of the amplitude attribute of the OVG gather after the pre-stack denoising process;
FIG. 12 is a schematic diagram of OVG gather before azimuthal anisotropy correction;
FIG. 13 is a schematic diagram of a OVG gather after azimuthal anisotropy correction;
FIG. 14 is a schematic diagram of regularization of OVG gather to CRP gather;
FIG. 15 is a schematic diagram of a comparison of a CRP gather obtained using a conventional prestack time shift and a CRP gather obtained using an embodiment of the present application;
FIG. 16 is a graph showing AVO attribute comparison of a CRP gather and an uphole forward gather obtained by the method of the present application;
FIG. 17 is a graph showing a comparison of a gradient curve of a CRP gather and an uphole forward gather obtained by the method of the present application;
FIG. 18 is a schematic diagram of AVO characteristic cluster analysis of a section of gas layer of a Qinglongtai region by a CRP gather obtained by an embodiment of the present application;
FIG. 19 is a schematic diagram of a common reflection point gather construction apparatus for pre-stack inversion according to an embodiment of the present application;
fig. 20 is a schematic diagram of a computer device according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the embodiments of the present application will be described in further detail with reference to the accompanying drawings. The exemplary embodiments of the present application and their descriptions herein are for the purpose of explaining the present application, but are not to be construed as limiting the application.
In the description of the present specification, the terms "comprising," "including," "having," "containing," and the like are open-ended terms, meaning including, but not limited to. The description of the reference terms "one embodiment," "a particular embodiment," "some embodiments," "for example," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. The order of steps involved in the embodiments is illustrative of the practice of the application, and is not limited and may be suitably modified as desired.
FIG. 1 is a flowchart of a method for constructing a common reflection point gather for pre-stack inversion according to an embodiment of the present application, as shown in FIG. 1, the method includes:
step 101, performing OVT gather extraction on a common reflection point CMP gather in original seismic data to generate an offset vector chip OVT gather;
102, performing prestack time migration on an OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets;
step 103, performing pre-stack denoising treatment on the OVG gather;
and 104, carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion.
In the embodiment of the application, the generated OVG gather has balanced overall energy, and can meet the requirement of pre-stack inversion; after that, the OVG gather is subjected to pre-stack denoising treatment, so that the signal to noise ratio of the OVG gather is improved, the influence of random noise on the amplitude is eliminated, and the precision of the finally obtained CRP gather is improved.
In the specific implementation, in step 101, OVT gather extraction is required to be performed on the common reflection point CMP gather in the original seismic data, so as to generate an OVT gather, which specifically includes the following steps:
in specific implementation, the OVT gather is extracted from the common reflection point CMP gather in the original seismic data, and there are various methods for generating the offset vector sheet OVT gather, and one of the following embodiments is given.
In one embodiment, performing OVT gather extraction on a common reflection point CMP gather in original seismic data to generate offset vector sheet OVT gathers, including:
extracting a common reflection point CMP gather in original seismic data into an OVT data body;
and performing OVT domain offset imaging on the OVT data body to obtain a offset vector piece OVG gather.
In the above embodiment, the OVT trace set includes a plurality of OVT slices, the bin definition of the OVT trace set (or referred to as OVT data) is first performed, then the CMP trace set is extracted into an OVT data body according to the bin definition of the OVT data, fig. 2 is a schematic diagram of the OVT data body extraction according to the embodiment of the present application, as shown in fig. 2 (a), the OVT data body includes a plurality of OVT blocks, the OVT data body extraction is performed on a cross arrangement, a single OVT block is taken out from all possible cross arrangements in the work area, as shown in fig. 2 (b), and then the single OVT blocks are combined together, as shown in fig. 2 (c), so as to form the OVT data body. The single OVT blocks have the same relative position in each cross arrangement and are decimated to form a single covered data volume having similar azimuth and offset.
OVT domain offset imaging of the OVT data volume may be performed using a conventional Kirchhoff offset module, with the resulting gather referred to as the OVG gather, also referred to as the spiral (Snail) gather, and the OVG gather comprising a plurality of prestack time offset post-OVT slices.
In specific implementations, there are various methods for performing pre-stack denoising on the OVG gather, and one example is given below.
In one embodiment, pre-stack denoising of OVG gathers, comprises:
carrying out random noise suppression treatment and/or linear interference suppression treatment on each OVT sheet of OVG gathers in a three-dimensional Tau-p domain to obtain each denoised OVT sheet;
all the OVT sheets after denoising are added to obtain OVG gather after prestack denoising.
In the above embodiment, each OVT sheet is equivalent to a three-dimensional data body with one coverage frequency, how many OVT sheets have three-dimensional data bodies with one coverage frequency, and then random noise suppression processing and/or linear interference suppression processing are performed on each OVT sheet in the three-dimensional Tau-p domain, so as to improve the signal to noise ratio of each OVT sheet, and obtain each denoised OVT sheet. The Tau-p transform is known as a linear transform, and if the number of channels involved in the transform is N, a linear signal will be N times stronger, still being random noise for random noise, according to the superposition characteristics. Therefore, the signal-to-noise ratio of the data in the three-dimensional Tau-p domain is higher than that of the time-space domain, and the signal and the noise are easy to identify because of the high signal-to-noise ratio of the data in the three-dimensional Tau-p domain, so that the noise suppression can be performed by a random noise suppression processing method in the three-dimensional Tau-p domain, and the signal-to-noise ratio of the OVT chip is improved. In addition, in the three-dimensional Tau-p domain, if weighted forward transformation is adopted, the linear signal is further enhanced, the linear interference is enhanced by utilizing the characteristic, then the linear interference is suppressed by utilizing a linear interference suppressing processing method in the three-dimensional Tau-p domain, and the signal to noise ratio of the finally obtained OVT sheet can be further improved. Adding all the OVT sheets subjected to denoising to obtain OVG gather, namely performing prestack denoising on OVG gather.
To further increase the accuracy of the CRP gather, in one embodiment, before the data regularization of the pre-stack denoised OVG gather, the method further includes:
performing azimuth anisotropy correction on OVG gathers subjected to pre-stack denoising treatment;
data regularization processing is carried out on OVG gathers after prestack denoising processing, and the method comprises the following steps:
and (5) carrying out data regularization processing on the OVG gather subjected to the orientation anisotropy correction.
In one embodiment, performing azimuthal anisotropy correction on the pre-stack denoising OVG gather, comprising:
picking up the time difference with azimuth information from the OVG gather after pre-stack denoising;
obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information;
performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction;
and (5) carrying out dynamic correction on the OVG gather after the reaction correction according to a speed function changing along with the azimuth angle.
In the embodiment, the direction anisotropy correction is performed on the OVG gather after the pre-stack denoising treatment, so that the influence of the anisotropy on the direction of the seismic wave amplitude, the reflection waveform and the phase along with the measuring line can be eliminated, and the OVG gather data is more beneficial to be regularized into the CRP gather under the condition of not considering the azimuth angle. The key to the correction of azimuth anisotropy is to find the velocity function as a function of azimuth angle, and to obtain the velocity function as a function of azimuth angle, two velocities must be obtained, parallel and perpendicular to the direction of symmetry axis. The method for realizing the azimuth anisotropy correction mainly comprises the following key steps: firstly, picking up time difference with azimuth information from OVG gathers after pre-stack denoising; then, according to the time difference with azimuth information, obtaining a speed function changing along with the azimuth angle, and calculating azimuth anisotropy attribute bodies, mainly a fast direction speed body, a slow direction speed body and a fast direction azimuth angle body, by mainly utilizing the time difference with the azimuth information, so as to obtain the speed function changing along with the azimuth angle; then, the OVG gather is subjected to reaction correction, namely the OVG gather is subjected to reaction correction mainly by using the original speed, and finally, the OVG gather subjected to reaction correction is subjected to reaction correction according to the speed function changing along with the azimuth angle.
In specific implementation, the method for obtaining the CRP gather by performing data regularization processing on the OVG gather subjected to the anisotropic correction of the orientation is various, and one embodiment is given below.
In one embodiment, the data regularization processing is performed on the OVG gather after the anisotropic correction of the azimuth, so as to obtain a CRP gather, which includes:
dividing the OVT track set subjected to azimuth anisotropy correction into a plurality of single offset data volumes;
performing Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components;
interpolation is carried out on each irregular data body, and a corresponding regular data body is obtained;
and selecting and arranging the plurality of regular data volumes into a three-dimensional data volume to form a CRP gather.
In the above embodiment, the OVG gather may be displayed in multiple dimensions, such as the spatial location of the OVG gather having four dimensions of crossline, inline, azimuth and offset, and the spatial location of the OVG gather having three dimensions of crossline, inline and offset when azimuth information is not considered, the OVG gather then exhibits CRP gather characteristics. However, the CRP gather is not unique in track number or missing in track number, so a data regularization technique is required to reconstruct the CRP gather data.
The regularization processing technology is that after the seismic data is subjected to multidimensional Fourier transform, the multidimensional seismic data reconstruction is easy to realize due to slow change in the wave number direction, and the calculation efficiency is greatly improved due to the use of rapid Fourier transform, so that the multidimensional data reconstruction method based on Fourier transform is very practical in practical seismic data. The core of the seismic data reconstruction method based on Fourier transformation is that irregular data is utilized to estimate Fourier coefficients of regular data, and then Fourier inverse transformation is carried out to obtain missing seismic data on a regular grid.
The data regularization processing of the OVG track set after the azimuth anisotropy correction specifically comprises the four steps, firstly, the OVG track set after the azimuth anisotropy correction is divided into a plurality of single offset data bodies; then, carrying out Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components; interpolation is carried out on each irregular data body, and difference values can be carried out according to a preconfigured grid, so that all empty channels are interpolated and reconstructed to obtain corresponding regular data bodies; and selecting and arranging the plurality of regular data bodies into a three-dimensional data body to form a CRP gather, wherein the selecting and arranging is to change the arrangement mode of the data under the condition of not changing the data of the plurality of regular data bodies so as to generate a desired arrangement mode.
Based on the above embodiments, the present application proposes an embodiment to explain a detailed flow of a method for constructing a common reflection point gather for pre-stack inversion, and fig. 3 is a detailed flow chart of the method for constructing a common reflection point gather for pre-stack inversion according to the embodiment of the present application, as shown in fig. 3, in which the detailed flow of the method for constructing a common reflection point gather for pre-stack inversion includes:
step 301, extracting a common reflection point CMP gather in original seismic data into an OVT data volume;
step 302, performing OVT domain offset imaging on an OVT data volume to obtain a OVG gather;
step 303, carrying out random noise suppression treatment and/or linear interference suppression treatment on each OVT sheet of the OVG gather in a three-dimensional Tau-p domain to obtain each denoised OVT sheet;
step 304, adding all the denoised OVT sheets to obtain OVG gather after pre-stack denoising treatment;
step 305, picking up the time difference with azimuth information from OVG gathers after pre-stack denoising;
step 306, obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information;
step 307, performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction;
step 308, dynamically correcting the OVG gather after the reaction correction according to a speed function changing along with the azimuth angle;
step 309, dividing the OVG track set after the azimuth anisotropy correction into a plurality of single offset data volumes;
step 310, performing fourier transform on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components;
step 311, interpolate each irregular data body to obtain a corresponding regular data body;
at step 312, the plurality of regular data volumes are sorted into three-dimensional data volumes to form a CRP gather.
Of course, it can be understood that other variations of the detailed flow of the method for constructing the common reflection point gather for pre-stack inversion are also possible, and all related variations should fall within the protection scope of the present application.
A specific embodiment is given below to illustrate a specific application of the common reflection point gather construction method for prestack inversion.
Taking seismic data of the eastern concave Qinglong platform of Liaohe oil field as an example, the earth surface of the area is plain and river beach, and the full coverage area is 450km 2 。
Firstly, extracting CMP trace sets in original seismic data of the region into OVT data; performing OVT domain pre-stack time migration imaging on OVT data to obtain a offset vector patch OVG gather, wherein FIG. 4 is a schematic diagram of a CRP gather obtained by adopting conventional pre-stack time migration, and FIG. 5 is a schematic diagram of a OVG gather obtained by adopting the method, and it can be seen that the CRP gather obtained by adopting the conventional pre-stack time migration has the characteristics of 'spindle-shaped' amplitude distribution with weak near offset and far offset amplitudes and strong medium offset amplitude, and cannot meet the requirement of inversion of a pre-stack reservoir. The OVG gather obtained through OVT domain migration imaging does not have the phenomenon, the whole energy is balanced, the requirement of inversion of a prestack reservoir is met, but the signal to noise ratio of the OVG gather is low, and the OVG gather is required to be subjected to signal to noise ratio improvement treatment.
Carrying out random noise suppression treatment and linear interference suppression treatment on each OVT sheet of OVG gathers in a three-dimensional Tau-p domain to obtain each denoised OVT sheet; adding all the denoised OVT sheets to obtain OVG gather after pre-stack denoising treatment; FIG. 6 is a schematic diagram of a OVG trace set before pre-stack denoising, FIG. 7 is a schematic diagram of a OVG trace set after pre-stack denoising, FIG. 8 is a schematic diagram of a superimposed cross section of a OVG trace set before pre-stack denoising, FIG. 9 is a schematic diagram of a superimposed cross section of a OVG trace set after pre-stack denoising, FIG. 6 is compared with FIG. 7, and FIG. 8 is compared with FIG. 9, as can be seen that the azimuthal anisotropy characteristics of a OVG trace set after pre-stack denoising are more pronounced; fig. 10 is a schematic diagram of the amplitude attribute of the OVG gather before the pre-stack denoising process, and fig. 11 is a schematic diagram of the amplitude attribute of the OVG gather after the pre-stack denoising process, it can be seen that the amplitude attribute of the OVG gather after the pre-stack denoising process is relatively maintained, and after the signal-to-noise ratio is improved, the amplitude attribute has better zonal property, and the influence of random noise on the amplitude is eliminated.
Picking up the time difference with azimuth information from the OVG gather after pre-stack denoising; obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information; performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction; according to the velocity function changing along with the azimuth angle, the OVG gather after the reaction correction is dynamically corrected, fig. 12 is a schematic diagram of OVG gathers before the azimuth anisotropy correction, fig. 13 is a schematic diagram of OVG gathers after the azimuth anisotropy correction, and it can be seen that after the azimuth anisotropy correction, the same phase axis is smoother, which is beneficial for regularization of OVG gathers into CRP gathers.
Dividing the OVG track set subjected to azimuth anisotropy correction into a plurality of single offset data bodies; performing Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components; interpolation is carried out on each irregular data body, and a corresponding regular data body is obtained; and selecting and arranging the plurality of regular data volumes into a three-dimensional data volume to form a CRP gather. Fig. 14 is a schematic diagram of regularization of OVG gathers to CRP gathers, fig. 14 (a) being OVG gathers and fig. 14 (b) being CRP gathers. Fig. 15 is a schematic diagram comparing a CRP gather obtained by using a conventional prestack time migration with a CRP gather obtained by using an embodiment of the present application, fig. 15 (a) is a CRP gather obtained by using a conventional prestack time migration, and fig. 15 (b) is a CRP gather obtained by using an embodiment of the present application, it can be seen that a CRP gather obtained by using an embodiment of the present application does not have a characteristic of strong offset energy in a weak far-path and a weak middle-path of a conventional CRP gather. Fig. 16 is a schematic diagram showing comparison of AVO properties of a CRP gather and an uphole forward gather obtained by the method according to the embodiment of the present application, and fig. 17 is a schematic diagram showing comparison of gradient curves of a CRP gather and an uphole forward gather obtained by the method according to the embodiment of the present application, and it can be seen that the AVO properties of a CRP gather according to the embodiment of the present application are consistent with the AVO properties of a forward gather, which illustrates that a CRP gather obtained by the method according to the embodiment of the present application is amplitude-preserving.
FIG. 18 is a schematic diagram of AVO characteristic clustering analysis of a section of gas layer in Qinglong platform region by using CRP gather obtained by the embodiment of the application, FIG. 18 shows that there are 10 wells in the region, wherein 5 are gas layers, 2 are dry layers, and 3 are water layers, table 1 shows actual oil test results of 10 wells in the region, and the final oil test results have a matching degree with AVO characteristic clustering analysis of 10 wells in FIG. 18 of up to 90%, wherein the actual oil test results of 5 wells are gas layers completely match with FIG. 18; only l20 did not agree, l20 in FIG. 18 being the aqueous layer, l20 in Table 1 being the dry layer. It can be seen from fig. 18 that no well has been drilled in the southern part of the area, and the method according to the embodiment of the present application can provide a reference for these non-drilled areas, thereby providing a solid foundation for increased production in the oil field.
TABLE 1 actual oil test conclusion of partial well in Qinglong table area
In summary, in the method provided by the embodiment of the application, OVT gather extraction is performed on the common reflection point CMP gather in the original seismic data, so as to generate offset vector sheet OVT gather; performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets; pre-stack denoising is carried out on the OVG gather; and carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion. Because the amplitudes of the near offset and the far offset of the CRP gather obtained by the conventional prestack time migration are weak, the amplitude of the middle offset is strong, and the requirement of prestack reservoir inversion cannot be met. The OVG gather generated by the embodiment of the application has balanced overall energy, and can meet the requirement of pre-stack inversion; after that, the OVG gather is subjected to pre-stack denoising treatment, so that the signal to noise ratio of the OVG gather is improved, the influence of random noise on the amplitude is eliminated, and the precision of the finally obtained CRP gather is improved.
Based on the same inventive concept, the embodiment of the application also provides a common reflection point gather construction device for prestack inversion, as described in the following embodiment. Since the principles of solving the problems are similar to those of the common reflection point gather construction method for pre-stack inversion, the implementation of the device can be referred to the implementation of the method, and the repetition is omitted.
Fig. 19 is a schematic diagram of a common reflection point gather construction apparatus for pre-stack inversion according to an embodiment of the present application, as shown in fig. 19, the apparatus includes:
the OVT gather generation module 1901 is configured to perform OVT gather extraction on the common reflection point CMP gather in the original seismic data, and generate an offset vector sheet OVT gather;
a pre-stack time migration module 1902, configured to perform pre-stack time migration on an OVT gather to generate a OVG gather, where the OVG gather includes a plurality of OVT slices after the pre-stack time migration;
a denoising processing module 1903, configured to perform pre-stack denoising processing on the OVT gather;
and a CRP gather obtaining module 1904, configured to perform data regularization processing on the pre-stack denoised OVT gather, and obtain a common reflection point CRP gather, where the CRP gather is used for pre-stack inversion.
In one embodiment, the OVT gather generation module 1901 is specifically configured to:
extracting a common reflection point CMP gather in original seismic data into an OVT data body;
OVT domain offset imaging was performed on OVT data volumes to obtain OVG gathers.
In one embodiment, the denoising processing module 1903 is specifically configured to:
carrying out random noise suppression treatment and/or linear interference suppression treatment on each OVT sheet of OVG gathers in a three-dimensional Tau-p domain to obtain each denoised OVT sheet;
all the OVT sheets after denoising are added to obtain OVG gather after prestack denoising.
In an embodiment, the apparatus further comprises a correction module 1905 for:
performing azimuth anisotropy correction on OVG gathers subjected to pre-stack denoising treatment;
CRP gather acquisition module 1904 is specifically configured to:
and (5) carrying out data regularization treatment on the OVG gather subjected to the orientation anisotropy correction to obtain a CRP gather.
In one embodiment, the correction module 1905 is specifically configured to:
picking up the time difference with azimuth information from the OVG gather after pre-stack denoising;
obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information;
performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction;
and (5) carrying out dynamic correction on the OVG gather after the reaction correction according to a speed function changing along with the azimuth angle.
In one embodiment, CRP gather acquisition module 1904 is specifically configured to:
dividing the OVG track set subjected to azimuth anisotropy correction into a plurality of single offset data bodies;
performing Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components;
interpolation is carried out on each irregular data body, and a corresponding regular data body is obtained;
and selecting and arranging the plurality of regular data volumes into a three-dimensional data volume to form a CRP gather.
In summary, in the device provided by the embodiment of the application, OVT gather extraction is performed on the common reflection point CMP gather in the original seismic data, so as to generate offset vector sheet OVT gather; performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets; pre-stack denoising is carried out on the OVG gather; and carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion. Because the amplitudes of the near offset and the far offset of the CRP gather obtained by the conventional prestack time migration are weak, the amplitude of the middle offset is strong, and the requirement of prestack reservoir inversion cannot be met. The OVG gather generated by the embodiment of the application has balanced overall energy, and can meet the requirement of pre-stack inversion; after that, the OVG gather is subjected to pre-stack denoising treatment, so that the signal to noise ratio of the OVG gather is improved, the influence of random noise on the amplitude is eliminated, and the precision of the finally obtained CRP gather is improved.
An embodiment of the present application further provides a computer device, and fig. 20 is a schematic diagram of the computer device in the embodiment of the present application, where the computer device can implement all the steps in the construction of the common reflection point gather for pre-stack inversion in the foregoing embodiment, and the electronic device specifically includes the following contents:
a processor (processor) 2001, a memory (memory) 2002, a communication interface (Communications Interface) 2003, and a bus 2004;
wherein the processor 2001, memory 2002, and communication interface 2003 complete communication with each other through the bus 2004; the communication interface 2003 is used for implementing information transmission among related devices such as server-side devices, detection devices, user-side devices and the like;
the processor 2001 is configured to invoke a computer program in the memory 2002, which when executed implements all the steps in the common reflection point gather construction method for pre-stack inversion in the above-described embodiment.
The embodiment of the present application further provides a computer readable storage medium, which can implement all the steps in the method for constructing a common reflection point gather for pre-stack inversion in the above embodiment, and the computer readable storage medium stores a computer program, and when the computer program is executed by a processor, the computer program implements all the steps in the method for constructing a common reflection point gather for pre-stack inversion in the above embodiment.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the application, and is not meant to limit the scope of the application, but to limit the application to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the application are intended to be included within the scope of the application.
Claims (6)
1. A method for constructing a common reflection point gather for prestack inversion, comprising:
performing OVT gather extraction on a common center point CMP gather in original seismic data to generate offset vector sheet OVT gathers;
performing prestack time migration on the OVT gather to generate a OVG gather, wherein the OVG gather comprises a plurality of prestack time-migrated OVT sheets;
pre-stack denoising is carried out on the OVG gather;
carrying out data regularization treatment on the OVG gather subjected to pre-stack denoising treatment to obtain a CRP gather, wherein the CRP gather is used for pre-stack inversion;
before the data regularization processing is carried out on the OVG gather after the prestack denoising processing, the CRP gather is obtained, the method further comprises the following steps: performing azimuth anisotropy correction on OVG gathers subjected to pre-stack denoising treatment;
performing data regularization processing on the OVG gather subjected to pre-stack denoising processing to obtain a CRP gather, wherein the method comprises the following steps of: performing data regularization treatment on the OVG gather subjected to the orientation anisotropy correction to obtain a CRP gather;
performing data regularization processing on the OVG gather subjected to the orientation anisotropy correction to obtain a CRP gather, wherein the method comprises the following steps of: dividing the OVG track set subjected to azimuth anisotropy correction into a plurality of single offset data bodies; performing Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components; interpolation is carried out on each irregular data body, and a corresponding regular data body is obtained; selecting and arranging a plurality of regular data volumes into three-dimensional data volumes to form a CRP gather;
when Fourier transformation is carried out on a plurality of single offset data volumes, irregular data is utilized to estimate Fourier coefficients of regular data, and then Fourier inverse transformation is carried out to obtain missing seismic data on a regular grid;
when each irregular data body is interpolated, interpolation is carried out according to a grid which is configured in advance, so that all empty channels are interpolated and reconstructed to obtain a corresponding regular data body;
when a plurality of rule data bodies are selected and arranged into a three-dimensional data body, the arrangement mode of the data is changed under the condition that the data of the plurality of rule data bodies is not changed, and a desired arrangement mode is generated;
azimuth anisotropy correction was performed on pre-stack denoising OVG gathers, including:
picking up the time difference with azimuth information from the OVG gather after pre-stack denoising;
obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information;
performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction;
and (5) carrying out dynamic correction on the OVG gather after the reaction correction according to a speed function changing along with the azimuth angle.
2. The method for constructing a common reflection point gather for pre-stack inversion according to claim 1, wherein performing pre-stack denoising on the OVG gather comprises:
carrying out random noise suppression treatment and/or linear interference suppression treatment on each OVT sheet of OVG gathers in a three-dimensional Tau-p domain to obtain each denoised OVT sheet;
all the OVT sheets after denoising are added to obtain OVG gather after prestack denoising.
3. A common reflection point gather construction apparatus for prestack inversion, comprising:
the OVT gather generation module is used for carrying out OVT gather extraction on the common center point CMP gather in the original seismic data to generate offset vector chip OVT gathers;
the pre-stack time migration module is used for performing pre-stack time migration on the OVT gather to generate a OVG gather, and the OVG gather comprises a plurality of pre-stack time migration OVT sheets;
the denoising processing module is used for carrying out prestack denoising processing on the OVG gather;
the CRP gather acquisition module is used for carrying out data regularization processing on the OVG gather subjected to pre-stack denoising processing to obtain a common reflection point CRP gather, wherein the CRP gather is used for pre-stack inversion;
the system further comprises a correction module for: performing azimuth anisotropy correction on OVG gathers subjected to pre-stack denoising treatment;
the CRP gather acquisition module is specifically configured to: performing data regularization treatment on the OVG gather subjected to the orientation anisotropy correction to obtain a CRP gather;
the CRP gather acquisition module is specifically configured to: dividing the OVG track set subjected to azimuth anisotropy correction into a plurality of single offset data bodies; performing Fourier transformation on the plurality of single offset data volumes to obtain a plurality of irregular data volumes with different frequency components; interpolation is carried out on each irregular data body, and a corresponding regular data body is obtained; selecting and arranging a plurality of regular data volumes into three-dimensional data volumes to form a CRP gather;
when Fourier transformation is carried out on a plurality of single offset data volumes, irregular data is utilized to estimate Fourier coefficients of regular data, and then Fourier inverse transformation is carried out to obtain missing seismic data on a regular grid;
when each irregular data body is interpolated, interpolation is carried out according to a grid which is configured in advance, so that all empty channels are interpolated and reconstructed to obtain a corresponding regular data body;
when a plurality of rule data bodies are selected and arranged into a three-dimensional data body, the arrangement mode of the data is changed under the condition that the data of the plurality of rule data bodies is not changed, and a desired arrangement mode is generated;
the correction module is specifically used for:
picking up the time difference with azimuth information from the OVG gather after pre-stack denoising;
obtaining a speed function changing along with the azimuth angle according to the time difference with azimuth information;
performing reaction correction on the OVG gather to obtain a OVG gather after reaction correction;
and (5) carrying out dynamic correction on the OVG gather after the reaction correction according to a speed function changing along with the azimuth angle.
4. The apparatus for constructing a common reflection point gather for prestack inversion according to claim 3, wherein the denoising processing module is specifically configured to:
carrying out random noise suppression treatment and/or linear interference suppression treatment on each OVT sheet of OVG gathers in a three-dimensional Tau-p domain to obtain each denoised OVT sheet;
all the OVT sheets after denoising are added to obtain OVG gather after prestack denoising.
5. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the processor implements the method of any of claims 1 to 2 when executing the computer program.
6. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program for executing the method of any one of claims 1 to 2.
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