Multi-path biased VSP interference earthquake method and device, electronic equipment and medium

Abstract

The invention discloses a multi-path biased VSP interference earthquake method and device, electronic equipment and a medium. The method may include: sorting biased VSP data into a common geophone gather; aiming at the common detection point gather, setting the length and the collection frequency of the multi-path signal; and multi-path signals of the two observation points A and B are calculated, and then a virtual seismic source waveform, namely a multi-path interference record, is calculated. According to the invention, interference calculation is carried out by using a multi-path summation principle, the energy intensity of underground effective reflection can be improved, and the energy of a cross phase is weakened by using the instability of the cross term.

Description

Technical Field

[0001] This invention relates to the field of biased VSP interferometric seismic methods, and more specifically, to a multipath biased VSP interferometric seismic method, apparatus, electronic device, and medium. Background Technology

[0002] The theoretical framework of the virtual source method states that if a given pair of receivers records wave fields excited on a closed surface surrounding the two receivers, then the true impulse response (i.e., Green's function) between the two receivers can be obtained by performing correlation calculations on the wave fields recorded by the two receivers and summing over all sources. VSP interferometry utilizes multiple wave information from VSP data to reconstruct pseudo-surface seismic data through virtual source construction, thereby increasing the number of stacks, significantly expanding the illumination (imaging) range, and enhancing the reservoir description capabilities of VSP data.

[0003] Imaging common shot gathers using reflected waves at different incident angles is extremely important because reflected waves with smaller incident angles result in better vertical resolution, while reflected waves with wider incident angles result in higher horizontal resolution. These conditions can be met by increasing the aperture width of the surface source or the geophone in the well. Utilizing higher-order multiples or other subsurface reflection mirrors, such as those from the seabed, can also increase the number of reflected waves and superpositions at different incident angles.

[0004] The current biased VSP interferometric algorithm mainly uses the Fermat path to construct virtual source ground seismic records, which is too simplistic.

[0005] Therefore, it is necessary to develop a multipath biased VSP interferometric seismic method, apparatus, electronic equipment, and medium.

[0006] The information disclosed in the background section of this invention is intended only to enhance the understanding of the general background of this invention, and should not be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art. Summary of the Invention

[0007] This invention proposes a multipath biased VSP interferometric seismic method, device, electronic equipment, and medium. It utilizes the multipath summation principle to perform interferometric calculations, which can improve the energy intensity of effective underground reflections, while using the instability of cross terms to reduce the energy of cross phases.

[0008] In a first aspect, embodiments of this disclosure provide a multipath biased VSP interferometric seismic method, including:

[0009] The biased VSP data is sorted into common receiver point gathers;

[0010] For the common detector point gather, set the length of the multipath signal and the number of acquisitions;

[0011] Calculate the multipath signals at two observation points A and B, and then calculate the virtual source waveform, which is the multipath interferometric record.

[0012] As one specific implementation of this disclosure, the length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

[0013] As one specific implementation of this disclosure, the multipath signal is collected 3-6 times.

[0014] As a specific implementation of this disclosure, the multipath signal of the j-th observation point A is:

[0015] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2)

[0016] Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

[0017] As a specific implementation of this disclosure, the multipath signal of the j-th observation point A is:

[0018] u iB =R iB (t iB +(j-1)dw / 2:T)

[0019] Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

[0020] As a specific implementation of this disclosure, the virtual vibration source waveform corresponding to the j-th vibration is:

[0021]

[0022] Where * represents convolution.

[0023] As a specific implementation of this disclosure, the multipath interference record is obtained by summing the waveforms of each virtual source.

[0024] Secondly, embodiments of this disclosure also provide a multipath biased VSP interferometric seismic device, comprising:

[0025] The sorting module sorts the biased VSP data into common receiver point gathers;

[0026] The processing module sets the length and number of acquisitions of the multipath signal for the common detector point gather;

[0027] The calculation module calculates the multipath signals of two observation points A and B, and then calculates the virtual source waveform, which is the multipath interferometric record.

[0028] As one specific implementation of this disclosure, the length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

[0029] As one specific implementation of this disclosure, the multipath signal is collected 3-6 times.

[0030] As a specific implementation of this disclosure, the multipath signal of the j-th observation point A is:

[0031] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2)

[0032] Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

[0033] As a specific implementation of this disclosure, the multipath signal of the j-th observation point A is:

[0034] u iB =R iB (t iB +(j-1)dw / 2:T)

[0035] Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

[0036] As a specific implementation of this disclosure, the virtual vibration source waveform corresponding to the j-th vibration is:

[0037]

[0038] Where * represents convolution.

[0039] As a specific implementation of this disclosure, the multipath interference record is obtained by summing the waveforms of each virtual source.

[0040] Thirdly, embodiments of this disclosure also provide an electronic device, the electronic device comprising:

[0041] Memory, which stores executable instructions;

[0042] A processor that executes the executable instructions in the memory to implement the multipath biased VSP interferometric seismic method.

[0043] Fourthly, embodiments of this disclosure also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements the described multipath biased VSP interferometric seismic method.

[0044] The methods and apparatus of the present invention have other features and advantages that will be apparent from or will be set forth in detail in the accompanying drawings and following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0045] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0046] Figure 1 A flowchart illustrating the steps of a multipath biased VSP interferometric seismic method according to an embodiment of the present invention is shown.

[0047] Figure 2a and Figure 2b Schematic diagrams of a single-path record and a multi-path record according to an embodiment of the present invention are shown respectively.

[0048] Figure 3 A schematic diagram of the biased VSP interference principle according to an embodiment of the present invention is shown.

[0049] Figure 4 A block diagram of a multipath biased VSP interferometric seismic apparatus according to an embodiment of the present invention is shown.

[0050] Explanation of reference numerals in the attached figures:

[0051] 201. Sorting module; 202. Processing module; 203. Calculation module. Detailed Implementation

[0052] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0053] 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 these examples are merely for the purpose of understanding the present invention, and any specific details therein are not intended to limit the present invention in any way.

[0054] Example 1

[0055] Figure 1 A flowchart illustrating the steps of a multipath biased VSP interferometric seismic method according to an embodiment of the present invention is shown.

[0056] like Figure 1 As shown, this multipath biased VSP interferometric seismic method includes:

[0057] Step 101: The biased VSP data is sorted into common receiver point gathers;

[0058] Step 102: For the common detector point gather, set the length of the multipath signal and the number of acquisitions;

[0059] Step 103: Calculate the multipath signals of the two observation points A and B, and then calculate the virtual source waveform, which is the multipath interferometric record.

[0060] In one example, the length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

[0061] In one example, the multipath signal was sampled 3-6 times.

[0062] In one example, the multipath signal at observation point A in the j-th observation is:

[0063] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2)

[0064] Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

[0065] In one example, the multipath signal at observation point A in the j-th observation is:

[0066] u iB =R iB (t iB +(j-1)dw / 2:T)

[0067] Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

[0068] In one example, the virtual source waveform corresponding to the j-th vibration is:

[0069]

[0070] Where * represents convolution.

[0071] In one example, the multipath interference record is obtained by summing the waveforms of each virtual source.

[0072] Figure 2a and Figure 2b Schematic diagrams of a single-path record and a multi-path record according to an embodiment of the present invention are shown respectively.

[0073] Specifically, during earthquake propagation, due to the inhomogeneity of the subsurface medium, waves propagate in multiple directions. Waves traveling along the Fermat propagation path reach the receiving end first, such as... Figure 2a , Figure 2b As shown. The multipath signal received by the receiver is:

[0074] S(t,x)=∫∫∫U(t0+τ(x′,x0))dx′ (1)

[0075] In the formula, S(x,x) is the multipath signal received by the receiver, x represents the coordinates of the receiver, t is the recording time; x′ represents all the locations through which the seismic wave propagates, t0 is the source excitation time, x0 is the excitation end location (source), and τ(x′,x0) is the travel time of the wave from the excitation end to x′.

[0076] Figure 3 A schematic diagram of the biased VSP interference principle according to an embodiment of the present invention is shown.

[0077] The principle of biased VSP interferometry is as follows: at observation points A and B, data from the source array D are recorded. i The wave field of (i = 1, 2, ..., I), such as Figure 3 As shown, their displacements represent u iA (t) and u iB (t). In the frequency domain, the wave field can be represented as follows:

[0078]

[0079] The interferometric algorithm can be expressed as:

[0080]

[0081] In the formula, the Green's function is a directly measured result. Therefore, the virtual source waveform VS(t) has a zero-phase spectrum. Assume W in equation (3) i =1 and transforming to the time domain, we have:

[0082]

[0083] The asterisk (*) in the formula represents convolution.

[0084] The specific implementation steps are as follows:

[0085] ① The biased VSP data is sorted into common receiver point gathers and the first arrival travel time is picked;

[0086] ② Select a common receiver point gather R ik (t), where i is the detector point number, k is the source point number, the multipath signal length dw is set (generally 2-3 times the period of the recorded signal wavelet), and the number of multipath signal acquisitions is N (generally 3-6 times).

[0087] ③ Let the initial arrival times of points A and B be t. iA ,t iB Where T is the total length of the record, and for the j-th multipath signal, we have:

[0088] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2) (5)

[0089] u iB =R iB (t iB +(j-1)dw / 2:T) (6)

[0090] According to formula (4), the relevant summation is obtained as VS. ABj .

[0091] ④ Repeat steps ② and ③ for all common receiver gathers to obtain N identical interferometric records. Sum and average all records to obtain the multipath interferometric record, i.e.

[0092] Example 2

[0093] The present invention also provides a multipath biased VSP interferometric seismic device, comprising:

[0094] The sorting module sorts the biased VSP data into common receiver point gathers;

[0095] The processing module sets the length and number of acquisitions for the multipath signal for the common detector point gather;

[0096] The calculation module calculates the multipath signals of two observation points A and B, and then calculates the virtual source waveform, which is the multipath interferometric record.

[0097] In one example, the length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

[0098] In one example, the multipath signal was sampled 3-6 times.

[0099] In one example, the multipath signal at observation point A in the j-th observation is:

[0100] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2)

[0101] Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

[0102] In one example, the multipath signal at observation point A in the j-th observation is:

[0103] u iB =R iB (t iB +(j-1)dw / 2:T)

[0104] Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

[0105] In one example, the virtual source waveform corresponding to the j-th vibration is:

[0106]

[0107] Where * represents convolution.

[0108] In one example, the multipath interference record is obtained by summing the waveforms of each virtual source.

[0109] Specifically, during earthquake propagation, due to the inhomogeneity of the subsurface medium, waves propagate in multiple directions. Waves traveling along the Fermat propagation path reach the receiving end first, such as... Figure 2a , Figure 2b As shown. The multipath signal received by the receiver is:

[0110] S(t,x)=∫∫∫U(t0+τ(x′,x0))dx′ (1)

[0111] In the formula, S(x,x) is the multipath signal received by the receiver, x represents the coordinates of the receiver, t is the recording time; x′ represents all the locations through which the seismic wave propagates, t0 is the source excitation time, x0 is the excitation end location (source), and τ(x′,x0) is the travel time of the wave from the excitation end to x′.

[0112] The principle of biased VSP interferometry is as follows: at observation points A and B, data from the source array D are recorded. i The wave field of (i = 1, 2, ..., I), such as Figure 3 As shown, their displacements represent u iA (t) and u iB (t). In the frequency domain, the wave field can be represented as follows:

[0113]

[0114] The interferometric algorithm can be expressed as:

[0115]

[0116] In the formula, the Green's function is a directly measured result. Therefore, the virtual source waveform VS(t) has a zero-phase spectrum. Assume W in equation (3) i =1 and transforming to the time domain, we have:

[0117]

[0118] The asterisk (*) in the formula represents convolution.

[0119] The specific implementation steps are as follows:

[0120] ① The biased VSP data is sorted into common receiver point gathers and the first arrival travel time is picked;

[0121] ② Select a common receiver point gather R ik (t), where i is the detector point number, k is the source point number, the multipath signal length dw is set (generally 2-3 times the period of the recorded signal wavelet), and the number of multipath signal acquisitions is N (generally 3-6 times).

[0122] ③ Let the initial arrival times of points A and B be t. iA ,t iB Where T is the total length of the record, and for the j-th multipath signal, we have:

[0123] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2) (5)

[0124] u iB =R iB (t iB +(j-1)dw / 2:T) (6)

[0125] According to formula (4), the relevant summation is obtained as VS. ABj .

[0126] ④ Repeat steps ② and ③ for all common receiver gathers to obtain N identical interferometric records. Sum and average all records to obtain the multipath interferometric record, i.e.

[0127] Example 3

[0128] ① The biased VSP data is sorted into common receiver point gathers and the first arrival travel time is picked;

[0129] ② Select a common receiver point gather R ik (t), where i is the detector point number, k is the source point number, the multipath signal length dw is set to twice the period of the recorded signal wavelet, and the number of multipath signal acquisitions is 5.

[0130] ③ Let the initial arrival times of points A and B be t. iA ,t iB Where T is the total length of the record, and for the j-th multipath signal, we have:

[0131] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2) (5)

[0132] u iB =R iB (t iB +(j-1)dw / 2:T) (6)

[0133] According to formula (4), the relevant summation is obtained as VS. ABj .

[0134] ④ Repeat steps ② and ③ for all common receiver gathers to obtain N identical interferometric records. Sum and average all records to obtain the multipath interferometric record, i.e.

[0135] Example 4

[0136] Figure 4 A block diagram of a multipath biased VSP interferometric seismic apparatus according to an embodiment of the present invention is shown.

[0137] like Figure 4 As shown, this multipath biased VSP interferometric seismic device includes:

[0138] Sorting module 201 sorts the biased VSP data into common receiver point gathers;

[0139] Processing module 202 sets the length and number of acquisitions of the multipath signal for the common detector point gather;

[0140] The calculation module 203 calculates the multipath signals of two observation points A and B, and then calculates the virtual source waveform, which is the multipath interferometric record.

[0141] In one example, the length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

[0142] In one example, the multipath signal was sampled 3-6 times.

[0143] In one example, the multipath signal at observation point A in the j-th observation is:

[0144] u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2)

[0145] Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

[0146] In one example, the multipath signal at observation point A in the j-th observation is:

[0147] u iB =R iB (t iB +(j-1)dw / 2:T)

[0148] Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

[0149] In one example, the virtual source waveform corresponding to the j-th vibration is:

[0150]

[0151] Where * represents convolution.

[0152] In one example, the multipath interference record is obtained by summing the waveforms of each virtual source.

[0153] Example 5

[0154] This disclosure provides an electronic device comprising: a memory storing executable instructions; and a processor executing the executable instructions in the memory to implement the aforementioned multipath biased VSP interferometric seismic method.

[0155] An electronic device according to an embodiment of the present disclosure includes a memory and a processor.

[0156] This 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, for example, include random access memory (RAM) and / or cache memory. The non-volatile memory may, for example, include read-only memory (ROM), hard disk, flash memory, etc.

[0157] The processor may be a central processing unit (CPU) or other form of processing unit with 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 this disclosure, the processor is used to execute computer-readable instructions stored in the memory.

[0158] Those skilled in the art will understand that, in order to solve the technical problem of how to achieve a good user experience, this embodiment may also include well-known structures such as communication buses and interfaces, and these well-known structures should also be included within the protection scope of this disclosure.

[0159] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0160] Example 6

[0161] This disclosure provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the described multipath biased VSP interferometric seismic method.

[0162] A computer-readable storage medium according to embodiments of the present disclosure stores non-transitory computer-readable instructions. When these non-transitory computer-readable instructions are executed by a processor, all or part of the steps of the methods described in the foregoing embodiments of the present disclosure are performed.

[0163] The aforementioned 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 portable hard drive), media with built-in rewritable non-volatile memory (e.g., memory card), and media with built-in ROM (e.g., ROM cartridge).

[0164] Those skilled in the art should understand that the above description of the embodiments of the present invention is only intended to 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 of the examples given.

[0165] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A multipath biased VSP interferometric seismic method, characterized in that, include: The biased VSP data is sorted into common receiver point gathers; For the common detector point gather, set the length of the multipath signal and the number of acquisitions; Calculate the multipath signals at two observation points A and B, and then calculate the virtual source waveform, which is the multipath interferometric record.

2. The multipath biased VSP interferometric seismic method according to claim 1, wherein, The length of the multipath signal is 2-3 times the period of the recorded signal wavelet.

3. The multipath biased VSP interferometric seismic method according to claim 1, wherein, The multipath signal is collected 3-6 times.

4. The multipath biased VSP interferometric seismic method according to claim 1, wherein, The multipath signal at observation point A in the j-th observation is: u iA =R iA (t iA -(j-1)dw / 2:t iA +(j-1)dw / 2) Among them, t iA Let d be the initial arrival time of point A, and dw be the length of the multipath signal.

5. The multipath biased VSP interferometric seismic method according to claim 4, wherein, The multipath signal at observation point A in the j-th observation is: u iB =R iB (t iB +(j-1)dw / 2:T) Among them, t iB Let T be the initial arrival time of point B, and T be the total length of the record.

6. The multipath biased VSP interferometric seismic method according to claim 5, wherein, The virtual source waveform corresponding to the j-th vibration is: Where * represents convolution.

7. The multipath biased VSP interferometric seismic method according to claim 6, wherein, The multipath interference record is obtained by summing the waveforms of each virtual source.

8. A multipath biased VSP interferometric seismic device, characterized in that, include: The sorting module sorts the biased VSP data into common receiver point gathers; The processing module sets the length and number of acquisitions of the multipath signal for the common detector point gather; The calculation module calculates the multipath signals of two observation points A and B, and then calculates the virtual source waveform, which is the multipath interferometric record.

9. An electronic device, characterized in that, The electronic device includes: Memory, which stores executable instructions; A processor that executes the executable instructions in the memory to implement the multipath biased VSP interferometric seismic method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the multipath biased VSP interferometric seismic method according to any one of claims 1-7.

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