Diffracted wave impedance inversion method and device, electronic equipment and medium

Abstract

The invention discloses a diffracted wave impedance inversion method and device, electronic equipment and a medium. The method comprises the following steps: carrying out recursive inversion on diffracted wave seismic data in a time domain to obtain diffracted wave relative impedance; converting the time domain interval velocity into interval velocity low-frequency impedance of the time domain; adding the diffracted wave relative impedance of the time domain and the layer velocity low-frequency impedance to obtain diffracted wave band-limited impedance; diffracted wave band-limited impedance and interval velocity low-frequency impedance of the time domain are converted into a frequency domain; diffracted wave absolute impedance of the frequency domain is obtained; and converting the diffracted wave absolute impedance of the frequency domain to obtain time domain diffracted wave absolute impedance. According to the method, the interval velocity is converted into the interval velocity low-frequency impedance through the conversion relation between the logging velocity and the impedance, and the interval velocity low-frequency impedance is fused with the relative impedance of diffracted wave recursion inversion in the frequency domain, so that the frequency band of diffracted wave impedance is widened, and the wave impedance inversion precision of the heterogeneous reservoir is improved.

Description

Technical Field

[0001] The present invention relates to the field of oil and gas geophysical exploration, and more specifically, to a diffraction wave impedance inversion method, device, electronic equipment and medium. Background Art

[0002] The Ordovician carbonate strata in the Tahe area have developed various fracture-cavity bodies, which provide space for oil and gas accumulation. In seismic records, fracture-cavity bodies show diffraction wave characteristics. At present, the fracture-cavity identification technology based on diffraction waves usually uses seismic attributes such as amplitude envelope to qualitatively characterize the contours of fracture-cavity bodies. However, there are few related studies on diffraction wave impedance inversion technology for quantitative prediction of fracture-cavity reservoirs at home and abroad.

[0003] The impedance information that can reflect the characteristics of fracture-cavity reservoirs can be obtained by using the diffraction wave impedance inversion technology, which is an important parameter for analyzing the storage performance and distribution law of fracture-cavity reservoirs. The diffraction wave impedance is analyzed from the frequency domain, which mainly contains two parts of information: one part is the relative impedance information from the medium-high frequency band of the diffraction wave seismic data, and the other part is the formation background impedance information in the low frequency band. In order to obtain the appropriate low-frequency background impedance, many geophysicists at home and abroad have proposed a wave impedance inversion low-frequency impedance construction method based on logging curve interpolation. This method first obtains the time domain wave impedance curve of the wellside track through well seismic calibration, and obtains the low-frequency component of the wave impedance of the control point of the wellside seismic track after filtering; then, according to the results of seismic structural interpretation, a stratigraphic framework model is established; finally, the wave impedance low-frequency component of the control point and the stratigraphic framework model are combined, and the initial model of wave impedance inversion is established by using the three-dimensional space interpolation method. This method is widely used in the wave impedance inversion of reservoirs with stable sedimentation and weak heterogeneity such as clastic rocks and shales. However, for highly heterogeneous reservoirs such as carbonate fracture-cave reservoirs, this method will interpolate and extrapolate the abnormal values ​​of the fracture-cave layer in the logging curve into the three-dimensional model, presenting a strip-like false anomaly along the layer on the initial section and a "bull's eye" anomaly illusion on the plane, resulting in inaccurate final post-stack wave impedance inversion results.

[0004] At present, there is still a need to develop a diffraction wave impedance inversion method based on seismic layer velocity.

[0005] The information disclosed in the background technology section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0006] The present invention proposes a diffraction wave impedance inversion method, device, electronic equipment and medium, which can realize diffraction wave impedance inversion by fusing layer velocity impedance and diffraction wave seismic relative impedance, recursively invert diffraction wave imaging data to obtain diffraction wave relative impedance, convert layer velocity in the pre-stack time migration process into layer velocity impedance, and fuse it with diffraction wave relative impedance in the frequency domain to obtain diffraction wave impedance inversion results based on seismic layer velocity, thereby improving the wave impedance inversion accuracy of heterogeneous reservoirs.

[0007] In a first aspect, an embodiment of the present disclosure provides a diffraction wave impedance inversion method, comprising:

[0008] Recursive inversion is performed on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance;

[0009] Convert the time domain layer velocity into the time domain layer velocity low frequency impedance;

[0010] Adding the diffraction wave relative impedance in the time domain to the layer velocity low-frequency impedance to obtain the diffraction wave band-limited impedance;

[0011] By Fourier transform, the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain are respectively converted into the frequency domain;

[0012] The diffraction wave band-limited impedance in the frequency domain is merged with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain;

[0013] The absolute impedance of the diffracted wave in the frequency domain is converted through inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain.

[0014] As a specific implementation of the embodiment of the present disclosure, recursive inversion is performed on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance, which includes:

[0015] In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and the wave impedance of the i-th layer;

[0016] The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained;

[0017] The impedance of the first to nth layers of each seismic trace is calculated to form the diffraction wave relative impedance.

[0018] As a specific implementation of the embodiment of the present disclosure, converting the time domain layer velocity into the time domain layer velocity low-frequency impedance includes:

[0019] The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained.

[0020] The layer velocity data volume generated in the prestack time migration process is converted into the layer velocity low-frequency impedance through the conversion relationship.

[0021] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance is:

[0022] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t)

[0023] Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

[0024] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance in the frequency domain is:

[0025] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0026] The layer velocity low frequency impedance in the frequency domain is:

[0027] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0028] Among them, f fourier (Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

[0029] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is:

[0030] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ)

[0031] Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

[0032] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is converted by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain, which includes:

[0033] Imp(t)=f inverse_fourier (Imp(ξ))

[0034] Among them, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

[0035] In a second aspect, the present disclosure also provides a diffraction wave impedance inversion device, including:

[0036] The inversion module performs recursive inversion on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance;

[0037] The conversion module determines the conversion relationship between the longitudinal wave velocity and the longitudinal wave impedance, and converts the time domain layer velocity into the time domain layer velocity low-frequency impedance;

[0038] An adding module, adding the relative impedance of the diffraction wave in the time domain to the low-frequency impedance of the layer velocity to obtain the band-limited impedance of the diffraction wave;

[0039] A Fourier transform module, which transforms the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain through Fourier transform;

[0040] A fusion module is used to fuse the diffraction wave band-limited impedance in the frequency domain with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain;

[0041] The inverse Fourier transform module converts the absolute impedance of the diffracted wave in the frequency domain through the inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain.

[0042] As a specific implementation of the embodiment of the present disclosure, recursive inversion is performed on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance, which includes:

[0043] In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and the wave impedance of the i-th layer;

[0044] The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained;

[0045] The impedance of the first to nth layers of each seismic trace is calculated to form the diffraction wave relative impedance.

[0046] As a specific implementation of the embodiment of the present disclosure, converting the time domain layer velocity into the time domain layer velocity low-frequency impedance includes:

[0047] The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained.

[0048] The layer velocity data volume generated in the prestack time migration process is converted into the layer velocity low-frequency impedance through the conversion relationship.

[0049] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance is:

[0050] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t)

[0051] Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

[0052] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance in the frequency domain is:

[0053] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0054] The layer velocity low frequency impedance in the frequency domain is:

[0055] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0056] Among them, f fourier (Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

[0057] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is:

[0058] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ)

[0059] Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

[0060] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is converted by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain, which includes:

[0061] Imp(t)=f inverse_fourier (Imp(ξ))

[0062] Among them, finverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

[0063] In a third aspect, an embodiment of the present disclosure further provides an electronic device, the electronic device comprising:

[0064] A memory storing executable instructions;

[0065] A processor runs the executable instructions in the memory to implement the diffraction wave impedance inversion method.

[0066] In a fourth aspect, an embodiment of the present disclosure further provides a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, the diffraction wave impedance inversion method is implemented.

[0067] Its beneficial effects are:

[0068] In view of the inversion problem of diffraction wave impedance, based on the layer velocity in the pre-stack time migration processing, the low-frequency impedance of layer velocity in the time domain is established through the conversion relationship between logging velocity and impedance, which avoids the strip-shaped anomalies and "bull's eye" anomalies existing in the logging interpolation model; the diffraction wave relative impedance is obtained by recursive inversion in the time domain, and combined with the low-frequency impedance of the layer velocity to obtain the diffraction wave band-limited impedance; it is integrated with the diffraction wave relative impedance in the frequency domain to broaden the frequency band of the diffraction wave impedance, and finally the diffraction wave impedance inversion result based on seismic layer velocity is obtained, thereby improving the wave impedance inversion accuracy of heterogeneous reservoirs.

[0069] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0071] Figure 1 A flow chart showing the steps of a diffraction wave impedance inversion method according to an embodiment of the present invention.

[0072] Figure 2 A schematic diagram of a time-domain full-wavefield seismic profile according to an embodiment of the present invention is shown.

[0073] Figure 3 A schematic diagram of a time-domain diffraction wave seismic profile according to an embodiment of the present invention is shown.

[0074] Figure 4 A schematic diagram of a time domain diffraction wave relative impedance profile according to an embodiment of the present invention is shown.

[0075] Figure 5 A schematic diagram of a time-domain layer velocity impedance profile according to an embodiment of the present invention is shown.

[0076] Figure 6 A schematic diagram of a time-domain diffraction wave band-limited impedance profile according to an embodiment of the present invention is shown.

[0077] Figure 7 A schematic diagram of a cross section of a time-domain diffraction wave impedance inversion result according to an embodiment of the present invention is shown.

[0078] Figure 8 A block diagram of a diffraction wave impedance inversion device according to an embodiment of the present invention is shown.

[0079] Description of reference numerals:

[0080] 201, inversion module; 202, conversion module; 203, addition module; 204, Fourier transform module; 205, fusion module; 206, inverse Fourier transform module. DETAILED DESCRIPTION

[0081] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0082] To facilitate understanding of the solutions and effects of the embodiments of the present invention, six specific application examples are given below. Those skilled in the art should understand that the examples are only for facilitating understanding of the present invention, and any specific details thereof are not intended to limit the present invention in any way.

[0083] Example 1

[0084] Figure 1 A flow chart showing the steps of a diffraction wave impedance inversion method according to an embodiment of the present invention.

[0085] like Figure 1 As shown, the diffraction wave impedance inversion method includes:

[0086] Step 101, recursively inverting the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance; in one example, recursively inverting the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance includes:

[0087] In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and wave impedance of the i-th layer;

[0088] The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained;

[0089] The impedance of the 1st to nth layers of each seismic trace is calculated to form the relative impedance of the diffraction wave.

[0090] Specifically, the time domain diffraction wave seismic data Seis(t) obtained by pre-stack time migration processing is known, and recursive inversion is performed on it to obtain the time domain diffraction wave relative impedance Imp_seis(t), where t represents the time point of time domain sampling, and the unit is s or ms.

[0091] It is known that the reflection coefficient sequence R(t) of the wave impedance interface is estimated using the diffraction wave seismic data Seis(t). The reflection coefficient R of the i-th layer is i Relationship with wave impedance Z i for

[0092]

[0093] The impedance of the i+1th layer can be determined by the impedance of the previous layer, the ith layer

[0094]

[0095] The impedance of the nth layer is expressed as

[0096]

[0097] The impedance of the 1st to nth layers of each seismic trace is calculated by the above formula, thus forming the final diffraction wave relative impedance Imp_seis(t).

[0098] Step 102, determining the conversion relationship between longitudinal wave velocity and longitudinal wave impedance, and converting the time domain layer velocity into the time domain layer velocity low-frequency impedance; in one example, converting the time domain layer velocity into the time domain layer velocity low-frequency impedance includes:

[0099] The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained.

[0100] The interval velocity data volume generated in the prestack time migration process is converted into interval velocity low-frequency impedance through the conversion relationship.

[0101] Specifically, the actual well logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained. vel_imp (Vel), the interval velocity data volume Vel(t) generated in the prestack time migration process can be converted into the interval velocity low-frequency impedance Imp_vel(t):

[0102] Imp_vel(t)=f vel-imp (Vel(t))

[0103] Where: Vel represents the longitudinal wave velocity, the unit is m / s.

[0104] Step 103, adding the relative impedance of the diffraction wave in the time domain to the low-frequency impedance of the layer velocity to obtain the band-limited impedance of the diffraction wave; in an example, the band-limited impedance of the diffraction wave is:

[0105] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t)

[0106] Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

[0107] Specifically, in the time domain, the diffraction wave band-limited impedance Imp_seis_band(t) can be obtained by adding the diffraction wave relative impedance Imp_seis(t) and the layer velocity low-frequency impedance Imp_vel(t):

[0108] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t).

[0109] Step 104, by Fourier transform, respectively convert the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain; in one example, the diffraction wave band-limited impedance in the frequency domain is:

[0110] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0111] The low-frequency impedance of the layer velocity in the frequency domain is:

[0112] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0113] Among them, f fourier(Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

[0114] Specifically, it is known that the Fourier transform f fourier (Imp), then the diffraction wave band-limited impedance Imp_seis_band(ξ) and the layer velocity low-frequency impedance Imp_vel(ξ) in the frequency domain are expressed as;

[0115] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0116] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0117] Where: Imp represents impedance, unit is m / s·kg / m 3 ; ξ represents the frequency value of frequency domain sampling, the unit is Hz.

[0118] Step 105, the diffraction wave band-limited impedance in the frequency domain is merged with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain; in an example, the diffraction wave absolute impedance in the frequency domain is:

[0119] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ)

[0120] Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

[0121] Specifically, in the frequency domain, the diffraction wave band-limited impedance Imp_seis_band(ξ) is fused with the layer velocity low-frequency impedance Imp_vel(ξ) to obtain the diffraction wave absolute impedance Imp(ξ) in the frequency domain.

[0122] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ).

[0123] Step 106, converting the absolute impedance of the diffracted wave in the frequency domain by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain. In one example, converting the absolute impedance of the diffracted wave in the frequency domain by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain includes:

[0124] Imp(t)=f inverse_fourier (Imp(ξ))

[0125] Among them, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

[0126] Specifically, by inverse Fourier transform f inverse_fourier (Imp), and the absolute impedance of the diffraction wave in the frequency domain Imp(ξ) is converted to the absolute impedance of the diffraction wave in the time domain Imp(t).

[0127] Imp(t)=f inverse_fourier (Imp(ξ)).

[0128] Example 1

[0129] The present invention also provides a diffraction wave impedance inversion device, comprising:

[0130] The inversion module recursively inverts the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance. In one example, recursively inverting the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance includes:

[0131] In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and wave impedance of the i-th layer;

[0132] The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained;

[0133] The impedance of the 1st to nth layers of each seismic trace is calculated to form the relative impedance of the diffraction wave.

[0134] Specifically, the time domain diffraction wave seismic data Seis(t) obtained by pre-stack time migration processing is known, and recursive inversion is performed on it to obtain the time domain diffraction wave relative impedance Imp_seis(t), where t represents the time point of time domain sampling, and the unit is s or ms.

[0135] It is known that the reflection coefficient sequence R(t) of the wave impedance interface is estimated using the diffraction wave seismic data Seis(t). The reflection coefficient R of the i-th layer is i Relationship with wave impedance Z i for

[0136]

[0137] The impedance of the i+1th layer can be determined by the impedance of the previous layer, the ith layer

[0138]

[0139] The impedance of the nth layer is expressed as

[0140]

[0141] The impedance of the 1st to nth layers of each seismic trace is calculated by the above formula, thus forming the final diffraction wave relative impedance Imp_seis(t).

[0142] The conversion module determines the conversion relationship between the longitudinal wave velocity and the longitudinal wave impedance, and converts the time domain layer velocity into the time domain layer velocity low-frequency impedance. In one example, converting the time domain layer velocity into the time domain layer velocity low-frequency impedance includes:

[0143] The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained.

[0144] The interval velocity data volume generated in the prestack time migration process is converted into interval velocity low-frequency impedance through the conversion relationship.

[0145] Specifically, the actual well logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained. vel_imp (Vel), the interval velocity data volume Vel(t) generated in the prestack time migration process can be converted into the interval velocity low-frequency impedance Imp_vel(t):

[0146] Imp_vel(t)=f vel-imp (Vel(t))

[0147] Where: Vel represents the longitudinal wave velocity, the unit is m / s.

[0148] The adding module adds the relative impedance of the diffraction wave in the time domain to the low-frequency impedance of the layer velocity to obtain the band-limited impedance of the diffraction wave. In an example, the band-limited impedance of the diffraction wave is:

[0149] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t)

[0150] Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

[0151] Specifically, in the time domain, the diffraction wave band-limited impedance Imp_seis_band(t) can be obtained by adding the diffraction wave relative impedance Imp_seis(t) and the layer velocity low-frequency impedance Imp_vel(t):

[0152] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t).

[0153] The Fourier transform module converts the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain through Fourier transform. In an example, the diffraction wave band-limited impedance in the frequency domain is:

[0154] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0155] The low-frequency impedance of the layer velocity in the frequency domain is:

[0156] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0157] Among them, f fourier (Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

[0158] Specifically, it is known that the Fourier transform f fourier (Imp), then the diffraction wave band-limited impedance Imp_seis_band(ξ) and the layer velocity low-frequency impedance Imp_vel(ξ) in the frequency domain are expressed as;

[0159] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0160] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0161] Where: Imp represents impedance, unit is m / s·kg / m 3 ; ξ represents the frequency value of frequency domain sampling, the unit is Hz.

[0162] The fusion module fuses the diffraction wave band-limited impedance in the frequency domain with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain. In an example, the diffraction wave absolute impedance in the frequency domain is:

[0163] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ)

[0164] Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

[0165] Specifically, in the frequency domain, the diffraction wave band-limited impedance Imp_seis_band(ξ) is fused with the layer velocity low-frequency impedance Imp_vel(ξ) to obtain the diffraction wave absolute impedance Imp(ξ) in the frequency domain.

[0166] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ).

[0167] The inverse Fourier transform module converts the absolute impedance of the diffracted wave in the frequency domain to obtain the absolute impedance of the diffracted wave in the time domain through the inverse Fourier transform. In one example, converting the absolute impedance of the diffracted wave in the frequency domain to obtain the absolute impedance of the diffracted wave in the time domain through the inverse Fourier transform includes:

[0168] Imp(t)=f inverse_fourier (Imp(ξ))

[0169] Among them, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

[0170] Specifically, by inverse Fourier transform f inverse_fourier (Imp), and the absolute impedance of the diffraction wave in the frequency domain Imp(ξ) is converted to the absolute impedance of the diffraction wave in the time domain Imp(t).

[0171] Imp(t)=f inverse_fourier (Imp(ξ)).

[0172] Example 3

[0173] Taking the carbonate fracture-vuggy reservoir in the Tarim Basin in northwest China as an example, the diffraction wave impedance inversion is performed using the method provided by the present invention.

[0174] Figure 2 A schematic diagram of a time domain full wave field seismic profile according to an embodiment of the present invention is shown. From the profile, it can be seen that within the time range of 3.3-3.7s, the fracture-cave geological anomaly body in the carbonate fracture-cave reservoir exhibits a "beaded" diffraction wave seismic response characteristic, which has strong heterogeneity.

[0175] Figure 3 A schematic diagram of a time domain diffraction wave seismic profile according to an embodiment of the present invention is shown. High-resolution diffraction waves have rich detailed information and can better depict the detailed features of fracture-cavity development.

[0176] Figure 4 A schematic diagram of a time domain diffraction wave relative impedance profile according to an embodiment of the present invention is shown.

[0177] For example Figure 3 The diffraction wave seismic profile shown in the figure uses the recursive inversion method to invert the relative impedance. The results are as follows Figure 4 shown.

[0178] Figure 5 A schematic diagram of a time-domain layer velocity impedance profile according to an embodiment of the present invention is shown.

[0179] The embodiment uses the Gardner formula to calculate the density from the longitudinal wave velocity, multiplies the longitudinal wave velocity and the density to obtain the longitudinal wave impedance, and uses the conversion relationship between the longitudinal wave velocity and the longitudinal wave impedance to convert the time domain layer velocity into the time domain layer velocity low-frequency impedance. The profile is as follows Figure 5 shown. Figure 5 The medium impedance has stable vertical and horizontal distribution, without layered and striped anomalies. The layer velocity impedance comes from the layer velocity data body generated in the prestack time migration process, which is completely matched with the seismic data and can provide reliable background impedance.

[0180] Figure 6 A schematic diagram of a time-domain diffraction wave band-limited impedance profile according to an embodiment of the present invention is shown.

[0181] Figure 7 A schematic diagram of a cross section of a time-domain diffraction wave impedance inversion result according to an embodiment of the present invention is shown.

[0182] Adding the diffraction wave relative impedance to the layer velocity impedance, we can get the diffraction wave band-limited impedance, as Figure 6 As shown. Through Fourier transform, the diffraction wave band-limited impedance and layer velocity impedance in the time domain are converted to the frequency domain respectively. In the frequency domain, the diffraction wave band-limited impedance and the layer velocity low-frequency impedance are merged to obtain the diffraction wave absolute impedance. Through the inverse Fourier transform, the final time domain diffraction wave absolute impedance is obtained, and the result is shown as follows: Figure 7 shown. Figure 7 The diffraction wave impedance profile shown in the figure combines the absolute impedance of the diffraction wave at medium and high frequencies with the layer velocity impedance at low frequencies. It has a wider frequency band and richer impedance information, thus improving the impedance inversion accuracy of heterogeneous reservoirs.

[0183] The present invention recursively inverts the diffraction wave imaging data to obtain the diffraction wave relative impedance, and then integrates the background low-frequency impedance established by pre-stack time migration processing layer velocity, which can effectively avoid the layered anomalies and "bull's eye" anomalies of the initial impedance model of conventional logging interpolation, and obtain the diffraction wave impedance inversion result based on seismic layer velocity, providing strong data support for subsequent oil and gas geophysical exploration in the study area.

[0184] Example 4

[0185] Figure 8A block diagram of a diffraction wave impedance inversion device according to an embodiment of the present invention is shown.

[0186] like Figure 8 As shown, the diffraction wave impedance inversion device comprises:

[0187] Inversion module 201, recursively inverts the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance;

[0188] The conversion module 202 determines the conversion relationship between the longitudinal wave velocity and the longitudinal wave impedance, and converts the time domain layer velocity into the time domain layer velocity low-frequency impedance;

[0189] An adding module 203 adds the relative impedance of the diffraction wave in the time domain to the low-frequency impedance of the layer velocity to obtain the band-limited impedance of the diffraction wave;

[0190] The Fourier transform module 204 transforms the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain through Fourier transform;

[0191] A fusion module 205 is used to fuse the diffraction wave band-limited impedance in the frequency domain with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain;

[0192] The inverse Fourier transform module 206 converts the absolute impedance of the diffracted wave in the frequency domain through inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain.

[0193] As a specific implementation of the embodiment of the present disclosure, recursive inversion is performed on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance, which includes:

[0194] In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and wave impedance of the i-th layer;

[0195] The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained;

[0196] The impedance of the 1st to nth layers of each seismic trace is calculated to form the relative impedance of the diffraction wave.

[0197] As a specific implementation of the embodiment of the present disclosure, converting the time domain layer velocity into the time domain layer velocity low-frequency impedance includes:

[0198] The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained.

[0199] The interval velocity data volume generated in the prestack time migration process is converted into interval velocity low-frequency impedance through the conversion relationship.

[0200] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance is:

[0201] Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t)

[0202] Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

[0203] As a specific implementation of the embodiment of the present disclosure, the diffraction wave band-limited impedance in the frequency domain is:

[0204] Imp_seis_band(ξ)=f fourier (Imp_seis_band(t))

[0205] The low-frequency impedance of the layer velocity in the frequency domain is:

[0206] Imp_vel(ξ)=f fourier (Imp_vel(t))

[0207] Among them, f fourier (Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

[0208] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is:

[0209] Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ)

[0210] Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

[0211] As a specific implementation of the embodiment of the present disclosure, the absolute impedance of the diffracted wave in the frequency domain is converted by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain, which includes:

[0212] Imp(t)=f inverse_fourier (Imp(ξ))

[0213] Among them, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

[0214] Example 5

[0215] The present disclosure provides an electronic device, which includes: a memory storing executable instructions; and a processor, which runs the executable instructions in the memory to implement the above-mentioned diffraction wave impedance inversion method.

[0216] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0217] The memory is used to store non-temporary computer-readable instructions. Specifically, the memory may include one or more computer program products, which may include various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory (cache), etc. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0218] The processor may be a central processing unit (CPU) or other forms of processing units having data processing capabilities and / or instruction execution capabilities, and may control other components in the electronic device to perform desired functions. In one embodiment of the present disclosure, the processor is used to run the computer-readable instructions stored in the memory.

[0219] Those skilled in the art should be able to understand that in order to solve the technical problem of how to obtain a good user experience, the present embodiment may also include well-known structures such as a communication bus and an interface, and these well-known structures should also be included in the protection scope of the present disclosure.

[0220] For detailed description of this embodiment, reference may be made to the corresponding descriptions in the aforementioned embodiments, which will not be repeated here.

[0221] Example 6

[0222] An embodiment of the present disclosure provides a computer-readable storage medium, which stores a computer program. When the computer program is executed by a processor, the diffraction wave impedance inversion method is implemented.

[0223] According to the computer-readable storage medium of the embodiment of the present disclosure, non-transitory computer-readable instructions are stored thereon. When the non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the method of each embodiment of the present disclosure are executed.

[0224] The above-mentioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or mobile hard disk), media with built-in rewritable non-volatile memory (e.g., memory card) and media with built-in ROM (e.g., ROM box).

[0225] Those skilled in the art should understand that the purpose of the above description of the embodiments of the present invention is only to exemplarily illustrate the beneficial effects of the embodiments of the present invention, and is not intended to limit the embodiments of the present invention to any given examples.

[0226] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A diffraction wave impedance inversion method, characterized in that: include: Recursive inversion is performed on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance; Convert the time domain layer velocity into the time domain layer velocity low frequency impedance; Adding the diffraction wave relative impedance in the time domain to the layer velocity low-frequency impedance to obtain the diffraction wave band-limited impedance; By Fourier transform, the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain are respectively converted into the frequency domain; The diffraction wave band-limited impedance in the frequency domain is merged with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain; The absolute impedance of the diffracted wave in the frequency domain is converted through inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain.

2. The diffraction wave impedance inversion method according to claim 1, wherein: Recursive inversion of diffraction wave seismic data in the time domain is performed to obtain the diffraction wave relative impedance including: In the time domain, the reflection coefficient sequence of the wave impedance interface is calculated using the diffraction wave seismic data to obtain the relationship between the reflection coefficient and the wave impedance of the i-th layer; The impedance of the i+1th layer is determined by the impedance of the ith layer until the impedance of the nth layer is obtained; The impedance of the first to nth layers of each seismic trace is calculated to form the diffraction wave relative impedance.

3. The diffraction wave impedance inversion method according to claim 1, wherein: The low-frequency impedances for converting time domain layer velocity to time domain layer velocity include: The actual logging curves in the study area were analyzed and the conversion relationship between P-wave velocity and P-wave impedance was obtained. The layer velocity data volume generated in the prestack time migration process is converted into the layer velocity low-frequency impedance through the conversion relationship.

4. The diffraction wave impedance inversion method according to claim 1, wherein: The diffraction band-limited impedance is: Imp_seis_band(t)=Imp_vel(t)+Imp_seis(t) Among them, Imp_seis_band(t) is the band-limited impedance of the diffraction wave, Imp_seis(t) is the relative impedance of the diffraction wave, and Imp_vel(t) is the low-frequency impedance of the layer velocity.

5. The diffraction wave impedance inversion method according to claim 1, wherein: The diffraction wave band-limited impedance in the frequency domain is: Imp_seis_band(ξ)=f fourier (Imp_seis_band(t)) The layer velocity low frequency impedance in the frequency domain is: Imp_vel(ξ)=f fourier (Imp_vel(t)) Among them, f fourier (Imp) is Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the layer velocity low-frequency impedance in the frequency domain, Imp represents impedance, and ξ represents the frequency value sampled in the frequency domain.

6. The diffraction wave impedance inversion method according to claim 1, wherein: The absolute impedance of the diffracted wave in the frequency domain is: Imp(ξ)=Imp_vel(ξ)+Imp_seis_abs(ξ) Among them, Imp(ξ) is the absolute impedance of the diffraction wave in the frequency domain, Imp_seis_band(ξ) is the band-limited impedance of the diffraction wave, and Imp_vel(ξ) is the low-frequency impedance of the layer velocity.

7. The diffraction wave impedance inversion method according to claim 1, wherein: The absolute impedance of the diffracted wave in the frequency domain is converted by inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain, which includes: Imp(t)=f inverse_fourier (Imp(ξ)) Among them, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the absolute impedance of the diffracted wave in the frequency domain, and Imp(t) is the absolute impedance of the diffracted wave in the time domain.

8. A diffraction wave impedance inversion device, characterized in that: include: The inversion module performs recursive inversion on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance; The conversion module determines the conversion relationship between the longitudinal wave velocity and the longitudinal wave impedance, and converts the time domain layer velocity into the time domain layer velocity low-frequency impedance; An adding module, adding the relative impedance of the diffraction wave in the time domain to the low-frequency impedance of the layer velocity to obtain the band-limited impedance of the diffraction wave; A Fourier transform module, which transforms the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain through Fourier transform; A fusion module is used to fuse the diffraction wave band-limited impedance in the frequency domain with the layer velocity low-frequency impedance to obtain the diffraction wave absolute impedance in the frequency domain; The inverse Fourier transform module converts the absolute impedance of the diffracted wave in the frequency domain through the inverse Fourier transform to obtain the absolute impedance of the diffracted wave in the time domain.

9. An electronic device, characterized in that: The electronic device comprises: A memory storing executable instructions; A processor, wherein the processor runs the executable instructions in the memory to implement the diffraction wave impedance inversion method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the diffraction wave impedance inversion method described in any one of claims 1 to 7 is implemented.

Images