A diffraction wave impedance inversion method and device, electronic equipment and medium

Abstract

The application discloses a diffraction wave impedance inversion method and device, electronic equipment and medium. The method can comprise: performing recursive inversion on diffraction wave seismic data in a time domain to obtain diffraction wave relative impedance; converting time domain layer velocity into time domain layer velocity low-frequency impedance; adding the time domain diffraction wave relative impedance and the layer velocity low-frequency impedance to obtain diffraction wave band-limited impedance; converting the time domain diffraction wave band-limited impedance and the layer velocity low-frequency impedance into a frequency domain respectively; obtaining frequency domain diffraction wave absolute impedance; and converting the frequency domain diffraction wave absolute impedance to obtain time domain diffraction wave absolute impedance. The application converts the layer velocity into layer velocity low-frequency impedance through a logging velocity and impedance conversion relationship, and combines the layer velocity low-frequency impedance with the relative impedance obtained through recursive inversion of the diffraction wave in the frequency domain, so that the frequency band of the diffraction wave impedance is widened, and the wave impedance inversion precision of a heterogeneous reservoir is improved.

Description

TECHNICAL FIELD

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

[0002] The fracture-cave bodies with various shapes are developed in the Ordovician carbonate rock strata in Tahe area, which provide space for oil and gas reservoirs. On the seismic record, the fracture-cave bodies are characterized by diffraction waves. At present, the fracture-cave identification technology based on diffraction waves is usually to qualitatively describe the outline of the fracture-cave bodies by using seismic attributes such as amplitude envelope. The diffraction wave impedance inversion technology for quantitatively predicting the fracture-cave reservoirs is less studied at home and abroad.

[0003] By using the diffraction wave impedance inversion technology, the impedance information reflecting the characteristics of the fracture-cave reservoirs can be obtained, which is an important parameter for analyzing the reservoir performance and distribution law of the fracture-cave 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 low-frequency background impedance information. In order to obtain suitable low-frequency background impedance, many geophysical workers at home and abroad have proposed a wave impedance inversion low-frequency impedance construction method based on the interpolation of logging curves. The method first obtains the time domain wave impedance curve of the well trace by well-to-seismic calibration, and obtains the low-frequency component of the wave impedance of the well seismic trace control point after filtering; then, a stratigraphic framework model is established according to the seismic structure interpretation results; finally, the wave impedance inversion initial model is established by using the three-dimensional space interpolation method combined with the wave impedance low-frequency component of the control point and the stratigraphic framework model. The method is widely used in the wave impedance inversion of sedimentary stable, weakly heterogeneous reservoirs such as clastic rocks and shales. However, for carbonate fracture-cave reservoirs and other strongly heterogeneous reservoirs, this method will extrapolate the abnormal values of the fracture-cave layer in the logging curve to the three-dimensional model, which presents a strip-shaped false anomaly along the layer on the initial profile and a "bull's eye" abnormal false image on the plane, resulting in inaccurate final post-stack wave impedance inversion results.

[0004] At present, a diffraction wave impedance inversion method based on seismic interval velocity needs to be developed.

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

[0006] The application provides a diffraction wave impedance inversion method and device, electronic equipment and medium, which can realize diffraction wave impedance inversion through fusion of layer velocity impedance and diffraction wave seismic phase relative impedance, recursively inverts diffraction wave imaging data to obtain diffraction wave relative impedance, converts layer velocity in pre-stack time migration into layer velocity impedance, and fuses the layer velocity impedance with the diffraction wave relative impedance in the frequency domain to obtain a diffraction wave impedance inversion result based on seismic layer velocity, thereby improving the wave impedance inversion precision of a heterogeneous reservoir.

[0007] In a first aspect, the embodiments of the present disclosure provide a diffraction wave impedance inversion method, comprising:

[0008] recursively inverting diffraction wave seismic data in the time domain to obtain diffraction wave relative impedance;

[0009] converting time domain layer velocity into time domain layer velocity low-frequency impedance;

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

[0011] converting the time domain diffraction wave band-limited impedance and the layer velocity low-frequency impedance into the frequency domain through Fourier transform;

[0012] fusing the frequency domain diffraction wave band-limited impedance and the layer velocity low-frequency impedance to obtain frequency domain diffraction wave absolute impedance;

[0013] converting the frequency domain diffraction wave absolute impedance through inverse Fourier transform to obtain time domain diffraction wave absolute impedance.

[0014] As a specific implementation manner of the embodiments of the present disclosure, recursively inverting diffraction wave seismic data in the time domain to obtain diffraction wave relative impedance comprises:

[0015] calculating a reflection coefficient sequence of a wave impedance interface by using the diffraction wave seismic data in the time domain to obtain a relationship between a reflection coefficient of the i th layer and wave impedance;

[0016] the impedance of the i+1 th layer is determined by the impedance of the i th layer, and the impedance of the n th layer is obtained;

[0017] calculating the impedance of the 1 st layer to the n th layer of each seismic trace to form the diffraction wave relative impedance.

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

[0019] performing cross analysis on actual logging curves of a study area to obtain a conversion relationship between P-wave velocity and P-wave impedance;

[0020] convert the layer velocity data volume generated in the pre-stack time migration process into the layer velocity low frequency impedance through the conversion relationship.

[0021] As a specific implementation manner 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] wherein, Imp_seis_band(t) is the diffraction wave band-limited impedance, Imp_seis(t) is the diffraction wave relative impedance, and Imp_vel(t) is the layer velocity low frequency impedance.

[0024] As a specific implementation manner 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] wherein, f fourier (Imp) is the 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, and Imp represents impedance, and ξ represents the frequency value of the frequency domain sampling.

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

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

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

[0032] As a specific implementation manner of the embodiment of the present disclosure, the diffraction wave absolute impedance in the frequency domain is converted through the inverse Fourier transform to obtain the diffraction wave absolute impedance in the time domain, including:

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

[0034] wherein f inverse_fourier (Imp) is an inverse Fourier transform, Imp(ξ) is a frequency domain diffraction wave absolute impedance, and Imp(t) is a time domain diffraction wave absolute impedance.

[0035] In a second aspect, the embodiments of the present disclosure further provide a diffraction wave impedance inversion device, comprising:

[0036] an inversion module configured to perform recursive inversion on diffraction wave seismic data in a time domain to obtain diffraction wave relative impedance;

[0037] a conversion module configured to determine a conversion relationship between P-wave velocity and P-wave impedance, and convert time domain interval velocity into time domain interval velocity low-frequency impedance;

[0038] an addition module configured to add the diffraction wave relative impedance in the time domain and the interval velocity low-frequency impedance to obtain diffraction wave band-limited impedance;

[0039] a Fourier transform module configured to convert the diffraction wave band-limited impedance in the time domain and the interval velocity low-frequency impedance into a frequency domain through Fourier transform;

[0040] a fusion module configured to fuse the diffraction wave band-limited impedance in the frequency domain and the interval velocity low-frequency impedance to obtain diffraction wave absolute impedance in the frequency domain;

[0041] a Fourier inverse transform module configured to convert the diffraction wave absolute impedance in the frequency domain through Fourier inverse transform to obtain time domain diffraction wave absolute impedance.

[0042] As a specific implementation manner of the embodiments of the present disclosure, the recursive inversion on the diffraction wave seismic data in the time domain to obtain the diffraction wave relative impedance comprises:

[0043] in the time domain, calculating a reflection coefficient sequence of a wave impedance interface by using the diffraction wave seismic data to obtain a relationship between a reflection coefficient of an i-th layer and wave impedance;

[0044] impedance of an i+1-th layer is determined by impedance of the i-th layer until impedance of an n-th layer is obtained;

[0045] impedance of the 1st layer to the n-th layer of each seismic trace is calculated to form the diffraction wave relative impedance.

[0046] As a specific implementation manner of the embodiments of the present disclosure, the conversion of the time domain interval velocity into the time domain interval velocity low-frequency impedance comprises:

[0047] performing cross-analysis on actual logging curves of a study area to obtain a conversion relationship between P-wave velocity and P-wave impedance;

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

[0049] As a specific implementation manner 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] Imp_seis_band(t) is the diffraction wave band-limited impedance, Imp_seis(t) is the diffraction wave relative impedance, and Imp_vel(t) is the layer velocity low frequency impedance.

[0052] As a specific implementation manner 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] Imp_vel(ξ)=f fourier (Imp) is the 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 of the frequency domain sampling.

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

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

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

[0060] As a specific implementation manner of the embodiment of the present disclosure, the diffraction wave absolute impedance in the frequency domain is converted through the inverse Fourier transform to obtain the diffraction wave absolute impedance in the time domain, including:

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

[0062] Imp(t)=finverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the frequency domain diffraction wave absolute impedance, and Imp(t) is the time domain diffraction wave absolute impedance.

[0063] In a third aspect, the embodiments of the present disclosure further provide an electronic device, which comprises:

[0064] a memory, which stores executable instructions;

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

[0066] In a fourth aspect, the embodiments of the present disclosure further provide a computer readable storage medium, which stores a computer program, and the computer program is executed by a processor to implement the diffraction wave impedance inversion method.

[0067] The beneficial effects are as follows:

[0068] For the inversion problem of diffraction wave impedance, the time domain low-frequency impedance of layer velocity is established through the conversion relationship between logging velocity and impedance on the basis of the layer velocity in the pre-stack time migration processing process, so that the strip-shaped abnormality and "bull's eye" abnormality existing in the logging interpolation model are avoided; the diffraction wave relative impedance is obtained through time domain recursive inversion, and the diffraction wave band-limited impedance is obtained in combination with the low-frequency impedance of layer velocity; in the frequency domain, the diffraction wave band-limited impedance is fused with the diffraction wave relative impedance, so that the frequency band of the diffraction wave impedance can be widened, and finally the diffraction wave impedance inversion result based on the seismic layer velocity is obtained, so that the wave impedance inversion precision of the heterogeneous reservoir is improved.

[0069] The method and apparatus of the present application have other characteristics and advantages that will be readily apparent from and / or will be more fully described in connection with the accompanying drawings and the subsequent detailed description, which together serve to explain the particular principles of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0070] The foregoing and other objects, features and advantages of the present application will become more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein like reference numerals are generally used to refer to like elements throughout, and in which:

[0071] Figure 1 A flowchart showing the steps of a diffraction wave impedance inversion method according to one embodiment of the present application is shown.

[0072] Figure 2 A schematic diagram of a time domain full wave field seismic profile according to one embodiment of the present application is shown.

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

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

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

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

[0077] Figure 7 A schematic diagram of a time domain diffracted wave impedance inversion result profile is shown according to an embodiment of the present application.

[0078] Figure 8 A block diagram of a diffracted wave impedance inversion apparatus is shown according to an embodiment of the present application.

[0079] BRIEF DESCRIPTION OF DRAWINGS

[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] Preferred embodiments of the present application will be described in more detail below. Although the following describes preferred embodiments of the present application, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein.

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

[0083] Example 1

[0084] Figure 1 A flowchart of steps of a diffracted wave impedance inversion method is shown according to an embodiment of the present application.

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

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

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

[0088] The impedance of the i+1-th layer is determined by the impedance of the i-th layer, until the impedance of the n-th layer is obtained;

[0089] The impedance of the 1st layer to the n-th layer of each seismic trace is calculated to form the diffraction wave relative impedance.

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

[0091] Given the reflection coefficient sequence R(t) of the wave impedance interface estimated by using the diffraction wave seismic data Seis(t), the reflection coefficient R i The relationship Z i is

[0092]

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

[0094]

[0095] The impedance of the n-th layer is represented as

[0096]

[0097] The impedance of the 1st layer to the n-th layer of each seismic trace is calculated to form the final diffraction wave relative impedance Imp_seis(t).

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

[0099] The conversion relationship between the P-wave velocity and the P-wave impedance is obtained by crossplotting the actual well logging curves of the study area;

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

[0101] Specifically, the actual logging curve of the research area is cross plotted to obtain the conversion relationship f vel_imp (Vel), the layer velocity data body Vel(t) generated in the pre-stack time migration process can be converted into the low frequency impedance Imp_vel(t):

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

[0103] In the formula, Vel represents the P-wave velocity, and the unit is m / s.

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

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

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

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

[0109] Step 104, the diffraction wave band-limited impedance and the low frequency impedance of the layer velocity in the time domain are respectively converted to the frequency domain by Fourier transform; in an 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] Wherein, f fourier(Imp) is a Fourier transform, Imp_seis_band(ξ) is a frequency-domain band-limited impedance of the diffraction wave, Imp_vel(ξ) is a frequency-domain low-frequency impedance of the layer velocity, Imp represents impedance, and ξ represents a frequency value of a frequency-domain sample.

[0114] Specifically, the Fourier transform f fourier (Imp), the frequency-domain band-limited impedance Imp_seis_band(ξ) of the diffraction wave and the low-frequency impedance Imp_vel(ξ) of the layer velocity are respectively represented as:

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

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

[0117] In the formula, Imp represents impedance, the unit is m / s·kg / m 3 ; ξ represents a frequency value of a frequency-domain sample, the unit is Hz.

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

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

[0120] In the formula, Imp(ξ) is the frequency-domain absolute impedance of the diffraction wave, 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 band-limited impedance Imp_seis_band(ξ) of the diffraction wave is fused with the low-frequency impedance Imp_vel(ξ) of the layer velocity to obtain the frequency-domain absolute impedance Imp(ξ) of the diffraction wave.

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

[0123] Step 106, the frequency-domain absolute impedance of the diffraction wave is converted through the Fourier inverse transform to obtain the time-domain absolute impedance of the diffraction wave. In one example, the frequency-domain absolute impedance of the diffraction wave is converted through the Fourier inverse transform to obtain the time-domain absolute impedance of the diffraction wave, including:

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

[0125] wherein f inverse_fourier (Imp) is an inverse Fourier transform, Imp(ξ) is a frequency domain diffraction wave absolute impedance, and Imp(t) is a time domain diffraction wave absolute impedance.

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

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

[0128] Example 1

[0129] The application further provides a diffraction wave impedance inversion device, comprising:

[0130] The inversion module performs recursive inversion on the diffraction wave seismic data in the time domain to obtain diffraction wave relative impedance; in one example, the recursive inversion on the diffraction wave seismic data in the time domain to obtain diffraction wave relative impedance comprises:

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

[0132] The impedance of the i+1-th layer is determined by the impedance of the i-th layer, until the impedance of the n-th layer is obtained;

[0133] The impedance of the 1st layer to the n-th layer of each seismic trace is calculated to form the diffraction wave relative impedance.

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

[0135] The reflection coefficient sequence R(t) of the wave impedance interface is estimated by using the diffraction wave seismic data Seis(t), and the reflection coefficient R i of the i-th layer is related to the wave impedance Z i .

[0136]

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

[0138]

[0139] The impedance of the n-th layer is represented as

[0140]

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

[0142] The conversion module determines a conversion relationship between the P-wave velocity and the P-wave impedance, and converts the time-domain layer velocity into time-domain layer velocity low-frequency impedance; in one example, converting the time-domain layer velocity into time-domain layer velocity low-frequency impedance comprises:

[0143] The conversion relationship between the P-wave velocity and the P-wave impedance is obtained by crossplotting the actual well logging curves of the study area;

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

[0145] Specifically, the conversion relationship f vel_imp (Vel) between the P-wave velocity and the P-wave impedance is obtained by crossplotting the actual well logging curves of the study area, so that the layer velocity data volume Vel(t) generated in the pre-stack time migration process can be converted into layer velocity low-frequency impedance Imp_vel(t):

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

[0147] In the formula, Vel represents the P-wave velocity, and the unit is m / s.

[0148] The adding module adds the time-domain relative diffraction wave impedance and the layer velocity low-frequency impedance to obtain a diffraction wave band-limited impedance; in one example, the diffraction wave band-limited impedance is:

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

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

[0151] Specifically, in the time domain, the diffraction wave band-limited impedance Imp_seis_band(t) can be obtained by adding the relative diffraction wave 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 time-domain diffraction wave band-limited impedance and the low-frequency impedance of the layer velocity into the frequency domain by 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] wherein f fourier (Imp) is the Fourier transform, Imp_seis_band(ξ) is the diffraction wave band-limited impedance in the frequency domain, Imp_vel(ξ) is the low-frequency impedance of the layer velocity in the frequency domain, Imp represents impedance, and ξ represents the frequency value of the frequency domain sampling.

[0158] Specifically, given the Fourier transform f fourier (Imp), the diffraction wave band-limited impedance Imp_seis_band(ξ) in the frequency domain and the low-frequency impedance Imp_vel(ξ) of the layer velocity are respectively represented as:

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

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

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

[0162] The fusion module fuses the diffraction wave band-limited impedance and the low-frequency impedance of the layer velocity in the frequency domain 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] wherein Imp(ξ) is the diffraction wave absolute impedance in the frequency domain, Imp_seis_band(ξ) is the diffraction wave band-limited impedance, 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 low-frequency impedance Imp_vel (ξ) of the layer velocity to obtain the diffraction wave absolute impedance Imp (ξ) in the frequency domain.

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

[0167] A Fourier inverse transform module converts the diffraction wave absolute impedance in the frequency domain into time domain diffraction wave absolute impedance through Fourier inverse transform.

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

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

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

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

[0172] Example 3

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

[0174] Figure 2 A schematic diagram of a time domain full wave field seismic profile according to one embodiment of the application is shown. As can be seen from the profile, in the time range of 3.3-3.7 s, the fracture-vug geological anomaly body in the carbonate fracture-vug reservoir shows the "bead" shaped diffraction wave seismic response characteristics, and has strong heterogeneity.

[0175] Figure 3 A schematic diagram of a time domain diffraction wave seismic profile according to one embodiment of the application is shown. The high-resolution diffraction wave detail information is relatively rich, and can better depict the detail characteristics of the fracture-vug body development.

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

[0177] For example Figure 3 The diffraction wave seismic profile shown in the figure is used to invert the relative impedance using the recursive inversion method. 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 impedance has a stable vertical and horizontal distribution, without layered or striped anomalies. The layer velocity impedance is derived from the layer velocity data volume generated in the prestack time migration process, which is completely matched with the seismic data and can provide reliable background impedance.

[0180] Figure 6 FIG. 4 is a schematic diagram showing a band-limited impedance profile of a time-domain diffraction wave according to an embodiment of the present invention.

[0181] Figure 7 A schematic diagram showing 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 relative impedance of the diffracted wave to the layer velocity impedance, we can get the band-limited impedance of the diffracted wave, 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 fused to obtain the diffraction wave absolute impedance. Through inverse Fourier transform, the final time domain diffraction wave absolute impedance is obtained, as shown in the following figure. 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 interval 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. This 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 diffracted wave impedance inversion device is shown according to an embodiment of the present application.

[0186] As shown in the figure, the diffracted wave impedance inversion device comprises: Figure 8

[0187] An inversion module 201 performs recursive inversion on diffracted wave seismic data in a time domain to obtain diffracted wave relative impedance;

[0188] A conversion module 202 determines a conversion relationship between P-wave velocity and P-wave impedance, and converts time domain interval velocity into time domain interval velocity low frequency impedance;

[0189] An addition module 203 adds the time domain diffracted wave relative impedance and the interval velocity low frequency impedance to obtain diffracted wave band-limited impedance;

[0190] A Fourier transform module 204 converts the time domain diffracted wave band-limited impedance and the interval velocity low frequency impedance into a frequency domain through Fourier transform;

[0191] A fusion module 205 fuses the frequency domain diffracted wave band-limited impedance and the interval velocity low frequency impedance to obtain frequency domain diffracted wave absolute impedance;

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

[0193] As a specific implementation manner of the embodiment of the present disclosure, the recursive inversion on the diffracted wave seismic data in the time domain to obtain the diffracted wave relative impedance comprises:

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

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

[0196] The impedance of the 1st layer to the n-th layer of each seismic trace is calculated to form the diffracted wave relative impedance.

[0197] As a specific implementation manner of the embodiment of the present disclosure, the conversion of the time domain interval velocity into the time domain interval velocity low frequency impedance comprises:

[0198] An intersection analysis is performed on actual well logging curves of a study area to obtain a conversion relationship between P-wave velocity and P-wave impedance;

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

[0200] ​As a specific implementation manner 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] wherein, Imp_seis_band(t) is the diffraction wave band-limited impedance, Imp_seis(t) is the diffraction wave relative impedance, and Imp_vel(t) is the layer velocity low-frequency impedance.

[0203] As a specific implementation manner 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 layer velocity low-frequency impedance in the frequency domain is:

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

[0207] wherein, f fourier (Imp) is the 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, and Imp represents impedance, and ξ represents the frequency value of the frequency domain sampling.

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

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

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

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

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

[0213] wherein, f inverse_fourier (Imp) is the inverse Fourier transform, Imp(ξ) is the diffraction wave absolute impedance in the frequency domain, and Imp(t) is the diffraction wave absolute impedance 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 running 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-transitory 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 include, for example, random access memory (RAM) and / or cache memory. The non-volatile memory may include, for example, read-only memory (ROM), a hard disk, flash memory, etc.

[0218] The processor may be a central processing unit (CPU) or other form of processing unit having data processing capability and / or instruction execution capability, 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 execute the computer-readable instructions stored in the memory.

[0219] Those skilled in the art should understand that in order to solve the technical problem of how to obtain a good user experience, this 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 scope of protection of this disclosure.

[0220] For detailed description of this embodiment, please refer to the corresponding description 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 storing 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 aforementioned methods of the embodiments of the present disclosure are executed.

[0224] The above computer readable storage medium includes, but is not limited to, an optical storage medium (for example, a CD-ROM and a DVD), a magneto-optical storage medium (for example, an MO), a magnetic storage medium (for example, a magnetic tape or a magnetic hard disk), a medium having a built-in rewritable nonvolatile memory (for example, a memory card), and a medium having a built-in ROM (for example, a ROM cartridge).

[0225] Those skilled in the art will understand that the above description of the embodiments of the present application is given for the purpose of exemplifying the advantageous effects of the embodiments of the present application and is not intended to limit the embodiments of the present application to any of the examples given.

[0226] The above has described the embodiments of the present application, and the above description is exemplary and is 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 diffraction wave impedance inversion method, characterized in that: include: Perform recursive inversion 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; Converting the diffraction wave band-limited impedance and the layer velocity low-frequency impedance in the time domain into the frequency domain respectively through Fourier transform; 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: Perform recursive inversion of diffraction wave seismic data in the time domain 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 relative impedance of the diffraction wave.

3. The diffraction wave impedance inversion method according to claim 1, wherein: The conversion of time domain interval velocity into time domain interval velocity low frequency impedance includes: 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 interval velocity data volume generated in the prestack time migration process is converted into the interval 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) Where 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 interval 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 the 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 interval 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 relative impedance of the diffraction wave; The conversion module determines the conversion relationship between longitudinal wave velocity and longitudinal wave impedance, and converts the time domain layer velocity into the time domain layer velocity low-frequency impedance; an adding module, which 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; A Fourier transform module, which 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; a fusion module, fusing 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 into the absolute impedance of the diffracted wave in the time domain through the inverse Fourier transform.

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 according to any one of claims 1 to 7 is implemented.

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