River channel identification method and device based on dominant band enhancement, equipment and medium

Abstract

The present application belongs to the technical field of petroleum and natural gas geophysical exploration, and relates to a river channel identification method and device based on advantage frequency band enhancement, equipment and medium. The method comprises: obtaining seismic data and extracting multiple seismic attributes; using a correlation evaluation function to select seismic attributes sensitive to river channel sand bodies; determining a frequency band range sensitive to the thickness of the target layer sand body through forward simulation; based on time-frequency analysis, using a frequency band enhancement function to obtain seismic data after advantage frequency band enhancement; using the seismic data after advantage frequency band enhancement to extract seismic attributes sensitive to the target layer sand body for river channel identification. The example application shows that the method can effectively identify river channels, is simple to apply, and has a strong application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of geophysical exploration, in particular to a river channel identification method based on advantage frequency band enhancement. BACKGROUND

[0002] River facies sand body reservoir is the main oil and gas reservoir in China's continental basins, but is affected by factors such as sand body thickness, physical property and superimposed relationship, so that it is difficult to clearly depict the river channel by conventional methods. There are mainly the following methods for depicting the river channel: (1) river channel identification method based on seismic attribute, which uses the difference between the river channel sand body and the surrounding rock in some specific seismic attribute to realize the river channel identification, but is affected by the different types of seismic attributes sensitive to the river channel sand body in different work areas, and usually a single attribute cannot effectively identify the river channel sand reservoir; (2) river channel identification method based on waveform classification, which uses seismic waveform information to identify the river channel based on the waveform variation characteristics of the river channel sand body, but the analysis window and the number of classification are difficult to determine, which has certain limitations in actual operation; (3) river channel identification method based on seismic frequency division interpretation technology, which uses different frequency data to tune the thickness and identify the river channel of different thickness by seismic frequency division processing, but is affected by the lateral variation of the river channel, so that it is difficult to accurately identify the overall distribution of the river channel by single frequency data.

[0003] The river facies sand body reservoir is affected by factors such as sand body thickness, physical property and superimposed relationship, so that its seismic response characteristics are not obvious, and it is difficult to clearly depict the river channel by conventional methods. SUMMARY

[0004] The river facies sand body reservoir is affected by factors such as sand body thickness, physical property and superimposed relationship, so that its seismic response characteristics are not obvious, and it is difficult to clearly depict the river channel by conventional methods. In order to make full use of the difference in sensitivity of different frequency bands to different thickness sand bodies, the present application optimizes the advantage frequency band sensitive to the river channel by forward modeling, and realizes the advantage frequency band enhancement by using the self-defined frequency band enhancement function based on the time-frequency analysis of the short-time Fourier transform, and extracts the sensitive seismic attribute by using the seismic data body after the advantage frequency band enhancement to depict the river channel.

[0005] In order to achieve the above purpose, the present application provides a river channel identification method based on advantage frequency band enhancement, which comprises the following steps:

[0006] acquiring seismic data and extracting a plurality of seismic attributes;

[0007] selecting the seismic attribute sensitive to the river channel sand body by using the correlation evaluation function;

[0008] determining the frequency band range sensitive to the sand body thickness of the target layer by forward modeling;

[0009] Based on time-frequency analysis, the seismic data after enhancement of dominant frequency band is obtained by using a frequency band enhancement function.

[0010] The seismic data after enhancement of dominant frequency band is used to extract seismic attributes sensitive to sand bodies of the target layer for channel recognition.

[0011] Further, before extracting multiple seismic attributes, the seismic data preprocessing is further included for optimizing the seismic data.

[0012] Further, the extraction of multiple seismic attributes includes extracting frequency, amplitude and phase seismic attributes from the optimized seismic data.

[0013] Further, through the extracted multiple seismic attributes, the logging and geological data are comprehensively used, and the correlation evaluation function is used to select the seismic attributes sensitive to the channel sand bodies.

[0014] Further, a correlation evaluation function h containing Spearman rank correlation coefficient and Pearson linear correlation coefficient is used to measure the relationship between the seismic attributes and the channel sand bodies.

[0015] h=a1*P+a2*ρ (1)

[0016]

[0017]

[0018] Wherein, X and Y respectively represent the sand body thickness on the well and the seismic attribute, N represents the number of them, and

[0019] Data x i and y i are reordered in ascending order, and the reordered positions are denoted as x′ i and x′ i , d i =x′ i -y′ i , ρ is the Spearman rank correlation coefficient, P is the Pearson linear correlation coefficient, a1 and a2 are the weighted coefficients.

[0020] Further, based on the short-time Fourier transform method, time-frequency analysis is carried out, and the frequency band enhancement function is used to carry out frequency band enhancement on the seismic data, and then the Fourier inverse transform is carried out to obtain the seismic data after enhancement of the dominant frequency band.

[0021] Further, the expression of the frequency band enhancement function is:

[0022]

[0023] Wherein, g is the amplitude spectrum after the dominant frequency band is enhanced, Amp is the amplitude spectrum of the original seismic data after the short-time Fourier transform, f represents the frequency, f1 is the lower limit frequency of the dominant frequency band, f2 is the upper limit frequency of the dominant frequency band, f max is the maximum frequency of the seismic data, and λ is an enhancement coefficient, indicating the size of the frequency band enhancement.

[0024] According to another aspect of the present application, a river channel identification device based on dominant frequency band enhancement is provided, comprising:

[0025] An extraction module acquires seismic data and extracts a plurality of seismic attributes;

[0026] A selection module selects seismic attributes sensitive to river channel sand bodies using a correlation evaluation function;

[0027] A determination module determines a frequency band range sensitive to the thickness of the target layer sand body through forward modeling;

[0028] An enhancement module acquires seismic data after the dominant frequency band is enhanced based on time-frequency analysis using a frequency band enhancement function;

[0029] An identification module extracts seismic attributes sensitive to the target layer sand body using the seismic data after the dominant frequency band is enhanced to identify the river channel.

[0030] According to another aspect of the present application, an electronic device is provided, comprising:

[0031] A memory storing executable instructions;

[0032] A processor running the executable instructions in the memory to implement the river channel identification method based on dominant frequency band enhancement.

[0033] According to another aspect of the present application, a non-transitory computer readable storage medium is provided, which stores a computer program, and the computer program is executed by a processor to implement the river channel identification method based on dominant frequency band enhancement.

[0034] The present application has the following innovations compared with the existing technology:

[0035] (1) The present application introduces a correlation evaluation function h containing Spearman rank correlation coefficient and Pearson linear correlation coefficient, which can comprehensively measure the linear and nonlinear relationship between variables, thereby helping to screen out attributes sensitive to river channels.

[0036] (2) The present application can effectively screen out a frequency band range sensitive to river channel sand bodies through forward modeling, and can effectively highlight seismic information in the dominant frequency band range through the defined frequency band enhancement function, thereby providing a solid data foundation for river channel identification.

[0037] (3) The present application can effectively identify the river channel which is difficult to be clearly identified by conventional methods through extracting sensitive seismic attributes based on the seismic data enhanced by the dominant frequency band. BRIEF DESCRIPTION OF DRAWINGS

[0038] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which like reference characters refer to like parts throughout the figures, and wherein:

[0039] Figure 1 A flow chart of the river channel identification method based on the dominant frequency band enhancement according to the present application.

[0040] Figure 2 A flow chart of the river channel identification method based on the dominant frequency band enhancement according to the present application.

[0041] Figure 3 The root mean square attribute of the post-stack data after optimization according to the present application.

[0042] Figure 4 The maximum wave trough attribute after the dominant frequency band enhancement according to the present application.

[0043] Figure 5 The frequency spectrum before and after the frequency band enhancement according to the present application.

[0044] Figure 6 The maximum wave trough attribute extracted after the dominant frequency band enhancement according to the present application. DETAILED DESCRIPTION

[0045] Preferred embodiments of the present application will be described herein below with more details. Although the preferred embodiments of the present application are described below, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0046] The present application belongs to the technical field of petroleum and natural gas geophysical exploration, and is a river channel identification method based on dominant frequency band enhancement. The seismic response characteristics of fluvial facies sand body reservoirs are not obvious due to the influence of factors such as sand body thickness, physical properties and superimposed relationship, and it is difficult to clearly depict the river channel by conventional methods.

[0047] The present application aims at these problems, firstly, based on the self-defined correlation evaluation function, the linear and nonlinear relationship between the seismic attribute and the channel sand body is comprehensively measured, and the attribute sensitive to the channel is screened out; then, the frequency band range sensitive to the channel sand body is screened out through forward simulation, and the seismic information in the dominant frequency band range is effectively highlighted through the defined frequency band enhancement function; finally, based on the seismic data enhanced by the dominant frequency band, the sensitive seismic attribute is extracted, and the channel recognition research is carried out. The example application shows that the method of the present application can effectively carry out the channel recognition research, and the application is simple, and has strong popularization and application prospect.

[0048] Embodiment one

[0049] As Figure 1 shown, the present embodiment provides a channel recognition method based on dominant frequency band enhancement, comprising:

[0050] acquiring seismic data and extracting a plurality of seismic attributes;

[0051] selecting the seismic attribute sensitive to the channel sand body by using the correlation evaluation function;

[0052] determining the frequency band range sensitive to the thickness of the sand body of the target layer through forward simulation;

[0053] based on time-frequency analysis, using the frequency band enhancement function, acquiring the seismic data enhanced by the dominant frequency band;

[0054] using the seismic data enhanced by the dominant frequency band, extracting the seismic attribute sensitive to the sand body of the target layer to carry out channel recognition.

[0055] Further, before extracting a plurality of seismic attributes, it also includes seismic data preprocessing for optimizing the seismic data.

[0056] Further, extracting a plurality of seismic attributes includes extracting frequency, amplitude and phase class seismic attributes in the optimized seismic data.

[0057] Further, through the extracted plurality of seismic attributes, the well logging and geological data are comprehensively measured, and the seismic attribute sensitive to the channel sand body is selected by using the previous understanding and the correlation evaluation function.

[0058] Further, a correlation evaluation function h containing Spearman rank correlation coefficient and Pearson linear correlation coefficient is used to measure the relationship between the seismic attribute and the channel sand body:

[0059] h=a1*P+a2*ρ (1)

[0060]

[0061]

[0062] Where X and Y represent the thickness of the sand body and seismic properties above the well, respectively, and N represents their number. The data x... i With y i Reorder the items in ascending order, and denote the sorted positions as x′. i and x′ i , d i =x′ i -y′ i ρ is the Spearman rank correlation coefficient, P is the Pearson linear correlation coefficient, and a1 and a2 are weighting coefficients.

[0063] Furthermore, based on the short-time Fourier transform method, time-frequency analysis is carried out, and a frequency band enhancement function is used to enhance the frequency band of the seismic data. Then, through inverse Fourier transform, the seismic data enhanced with the dominant frequency band is obtained.

[0064] Furthermore, the expression for the band enhancement function is:

[0065]

[0066] Where g is the amplitude spectrum after enhancement of the dominant frequency band, Amp is the amplitude spectrum of the original seismic data after short-time Fourier transform, f represents the frequency, f1 is the lower limit frequency of the dominant frequency band, f2 is the upper limit frequency of the dominant frequency band, and f... max λ represents the maximum frequency of the seismic data, and λ is the enhancement coefficient, indicating the magnitude of the frequency band enhancement.

[0067] Example 2

[0068] like Figure 2 As shown, this embodiment aims to highlight river channel characteristics through dominant frequency band enhancement, thereby enabling river channel identification. The method flow is as follows: First, seismic data preprocessing to obtain optimized seismic data; second, extracting various seismic attributes based on post-stack seismic data; third, seismic attribute optimization, using a custom correlation evaluation function to select seismic attributes sensitive to river channel sand bodies; fourth, determining the dominant frequency band through forward modeling; fifth, dominant frequency band enhancement, based on time-frequency analysis, using a custom frequency band enhancement function to highlight seismic information within the dominant frequency band range; sixth, extracting sensitive seismic attributes for river channel identification.

[0069] Specifically, the method of this embodiment is performed according to the following steps:

[0070] Step 1: Seismic data preprocessing. This mainly includes operations such as removing outliers from the seismic data to obtain optimized seismic data.

[0071] Step two: Seismic attribute extraction. Based on the optimized seismic data, extract a variety of seismic attributes including frequency, amplitude and phase.

[0072] Step three: Seismic attribute optimization. Through the extracted variety of seismic attributes, integrate well logging and geological data, and use the previous understanding and correlation analysis method to optimize the seismic attributes sensitive to the channel sand.

[0073] The relationship between different seismic attributes and channel sand bodies is inconsistent. In order to fully measure the linear or nonlinear relationship between seismic attributes and channel sand bodies, a correlation evaluation function h containing Spearman rank correlation coefficient and Pearson linear correlation coefficient is designed to measure the relationship between seismic attributes and channel sand bodies.

[0074] h = a1*P + a2*ρ (1)

[0075]

[0076]

[0077] Where X, Y represent the sand thickness on the well and the seismic attribute respectively, and N represents their number. The data x i and y i are reordered in ascending order, and the reordered positions are x′ i and x′ i , d i = x′ i -y′ i , ρ is the Spearman rank correlation coefficient, P is the Pearson linear correlation coefficient, a1 and a2 are the weighting coefficients.

[0078] Step four: Determine the dominant frequency band. Through forward modeling, determine the frequency band range sensitive to the sand thickness of the target layer.

[0079] Step five: Dominant frequency band enhancement. Based on the short-time Fourier transform method, carry out time-frequency analysis, and use the following function to enhance the frequency band of the seismic data. Then, through inverse Fourier transform, obtain the seismic data after the enhancement of the dominant frequency band.

[0080]

[0081] Where g is the amplitude spectrum after the enhancement of the dominant frequency band, Amp is the amplitude spectrum of the original seismic data after the short-time Fourier transform, f represents the frequency, f1 is the lower limit frequency of the dominant frequency band, f2 is the upper limit frequency of the dominant frequency band, f max is the maximum frequency of the seismic data, λ is the enhancement coefficient, indicating the size of the frequency band enhancement.

[0082] Step six: river channel identification based on the data enhanced by the dominant frequency band. The seismic data enhanced by the dominant frequency band is used to extract the seismic attribute sensitive to the sand body of the target layer for river channel identification.

[0083] Embodiment three

[0084] Referring to Figures 3-6 The embodiment takes an example to illustrate the implementation process and application effect of the present application. Taking the data of a practical work area in China as an example, the river channel identification research is carried out based on the method mentioned in the present application.

[0085] Step one: seismic data preprocessing. The optimized seismic data is obtained by removing outliers and other operations on the seismic data.

[0086] Step two: seismic attribute extraction. Based on the optimized seismic data, a plurality of seismic attributes of the target layer are extracted, Figure 3 The root mean square amplitude attribute map of the post-stack data of the target layer after optimization is shown.

[0087] Step three: seismic attribute optimization. Based on the plurality of extracted seismic attributes, the well logging and geological data are comprehensively used to optimize the river channel sand sensitive attribute by using the correlation evaluation function h, and the maximum trough attribute in the research area is the most sensitive attribute of the river channel sand, Figure 4 The maximum trough attribute map of the post-stack data of the target layer after optimization is shown.

[0088] Step four: determination of the dominant frequency band. The frequency band range sensitive to the thickness of the target layer sand body is determined to be 30-50 Hz through forward modeling.

[0089] Step five: enhancement of the dominant frequency band. Based on the short-time Fourier transform method, time-frequency analysis is carried out, and the defined band enhancement function (formula 4) is used to enhance the seismic data in the frequency band, and then the Fourier inverse transform is carried out to obtain the seismic data enhanced by the dominant frequency band, Figure 5 The frequency spectrum before and after the band enhancement is shown.

[0090] Step six: river channel identification based on the data enhanced by the dominant frequency band. The seismic data enhanced by the dominant frequency band is used to extract the seismic attribute sensitive to the sand body of the target layer for river channel identification, Figure 4 It can be seen that, compared with the maximum trough attribute extracted from the optimized seismic data, Figure 4 the maximum trough attribute extracted after the enhancement of the dominant frequency band has more obvious river channel characteristics and better river channel continuity (as shown by the arrows in the figure), which proves that the method of the present application can effectively identify the river channel.

[0091] Embodiment four

[0092] The embodiment provides a river channel identification device based on the enhancement of the dominant frequency band, which comprises:

[0093] The extraction module acquires seismic data and extracts multiple seismic attributes;

[0094] The selection module selects seismic attributes sensitive to the channel sand body by using a correlation evaluation function;

[0095] The determination module determines a frequency band range sensitive to the thickness of the target layer sand body through forward simulation;

[0096] The enhancement module acquires seismic data enhanced by the dominant frequency band based on time-frequency analysis and using a frequency band enhancement function;

[0097] The identification module extracts seismic attributes sensitive to the target layer sand body from the seismic data enhanced by the dominant frequency band to identify the channel.

[0098] Embodiment five

[0099] The electronic device comprises:

[0100] The memory stores executable instructions;

[0101] The processor runs the executable instructions in the memory to implement the channel identification method based on the dominant frequency band enhancement. The method comprises: acquiring seismic data and extracting multiple seismic attributes; selecting seismic attributes sensitive to the channel sand body by using a correlation evaluation function; determining a frequency band range sensitive to the thickness of the target layer sand body through forward simulation; acquiring seismic data enhanced by the dominant frequency band based on time-frequency analysis and using a frequency band enhancement function; and extracting seismic attributes sensitive to the target layer sand body from the seismic data enhanced by the dominant frequency band to identify the channel.

[0102] Embodiment six

[0103] The non-transitory computer readable storage medium stores a computer program, which, when executed by a processor, implements the channel identification method based on the dominant frequency band enhancement. The method comprises: acquiring seismic data and extracting multiple seismic attributes; selecting seismic attributes sensitive to the channel sand body by using a correlation evaluation function; determining a frequency band range sensitive to the thickness of the target layer sand body through forward simulation; acquiring seismic data enhanced by the dominant frequency band based on time-frequency analysis and using a frequency band enhancement function; and extracting seismic attributes sensitive to the target layer sand body from the seismic data enhanced by the dominant frequency band to identify the channel.

[0104] The computer readable storage medium includes, but is not limited to, optical storage media (such as CD-ROM and DVD), magneto-optical storage media (such as MO), magnetic storage media (such as magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (such as memory card), and media with built-in ROM (such as ROM cartridge).

[0105] In summary, the application is based on a self-defined correlation evaluation function, which comprehensively measures the linear and nonlinear relationship between seismic attributes and channel sand bodies, and screens out attributes sensitive to channels; through forward simulation, the frequency band range sensitive to channel sand bodies is screened out, through a defined frequency band enhancement function, the seismic information in the dominant frequency band range is effectively highlighted; finally, based on the enhanced seismic data in the dominant frequency band, sensitive seismic attributes are extracted for channel identification research. Example application shows that the method of the application can effectively perform channel identification research, and is simple to apply, and has strong application prospect.

[0106] The above has described various embodiments of the application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A river identification method based on dominant band enhancement, characterized in that, The method comprises: acquiring seismic data and extracting multiple seismic attributes; selecting seismic attributes sensitive to channel sand bodies by using a correlation evaluation function; determining a frequency band range sensitive to sand body thickness of a target layer by forward modeling; obtaining seismic data after enhancement of a dominant frequency band based on time-frequency analysis and using a frequency band enhancement function; extracting seismic attributes sensitive to sand bodies of the target layer from the seismic data after enhancement of the dominant frequency band, and identifying channels. 2.The river identification method based on dominant band enhancement according to claim 1, characterized in that, Before the multiple seismic attributes are extracted, the method further comprises seismic data preprocessing for optimizing the seismic data. 3.The river identification method based on dominant band enhancement according to claim 2, characterized in that, The multiple seismic attributes are extracted from the optimized seismic data, including frequency, amplitude and phase seismic attributes. 4.The river identification method based on dominant band enhancement according to claim 3, characterized in that, The extracted multiple seismic attributes are used in combination with well logging and geological data to select seismic attributes sensitive to channel sand bodies by using a correlation evaluation function and previous knowledge.

5. The river identification method based on the advantage band enhancement according to claim 1 or 4, characterized in that, A correlation evaluation function h containing a Spearman rank correlation coefficient and a Pearson linear correlation coefficient is used to measure the relationship between the seismic attributes and the channel sand bodies. （1） （2） （3） where, denote the sand thickness and seismic attribute respectively, denote their number, and the data and are reordered in ascending order, and the reordered position is denoted as and , and , is the Spearman rank correlation coefficient, P is the Pearson linear correlation coefficient, and are weighting coefficients. 6.The river identification method based on dominant band enhancement according to claim 1, wherein, Time-frequency analysis is carried out based on a short-time Fourier transform method, and a frequency band enhancement function is used to enhance the seismic data in a frequency band, and then inverse Fourier transform is carried out to obtain seismic data after enhancement of a dominant frequency band.

7. The river identification method based on the advantage band enhancement according to claim 1 or 6, characterized in that, The expression of the frequency band enhancement function is: （4） wherein g is the amplitude spectrum after the dominant frequency band is enhanced, Amp is the amplitude spectrum of the original seismic data after short-time Fourier transform, denotes the frequency, is the lower limit frequency of the dominant frequency band, is the upper limit frequency of the dominant frequency band, is the maximum frequency of the seismic data, is the enhancement coefficient, indicating the size of the frequency band enhancement.

8. A river course recognition device based on dominant band enhancement, characterized by, The method comprises: an extraction module for acquiring seismic data and extracting multiple seismic attributes; a selection module for selecting seismic attributes sensitive to channel sand bodies by using a correlation evaluation function; a determination module for determining a frequency band range sensitive to sand body thickness of a target layer by forward modeling; an enhancement module for obtaining seismic data after enhancement of a dominant frequency band based on time-frequency analysis and using a frequency band enhancement function; an identification module for extracting seismic attributes sensitive to sand bodies of the target layer from the seismic data after enhancement of the dominant frequency band, and identifying channels.

9. An electronic device, comprising: The electronic device comprises: a memory storing executable instructions; a processor running the executable instructions in the memory to implement the method for identifying channels based on enhancement of a dominant frequency band according to any one of claims 1-7. 10.A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by a processor to implement the method for identifying channels based on enhancement of a dominant frequency band according to any one of claims 1-7.

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