Method, device and apparatus for determining velocity of underground medium

Abstract

The present disclosure provides a method, device, and equipment for determining the velocity of underground media, which relates to seismic data processing technology, including: using seabed nodes to collect seismic data generated by exciting a single-stage sub-source at a shot point; determining a dipole source and a zero-phase single-stage sub-source based on the single-stage sub-source; combining the dipole source and the zero-phase single-stage sub-source to obtain a directional sub-wave; exchanging the position of the seabed node with the position of the shot point; and using the exchanged node to collect seismic simulation data generated by exciting the directional sub-wave at the exchanged shot point; and determining the target velocity model based on the upgoing wave of the seismic data and the seismic simulation data. In this solution, the single-stage sub-source is processed and a directional sub-wave with directional characteristics is obtained. The seismic simulation data that excites the directional sub-wave at the shot point is collected, and the velocity model is determined using the seismic simulation data and the upgoing wave of the seismic data. The accuracy of the velocity model can be improved.

Description

Technical Field

[0001] The present disclosure relates to seismic data processing technology, and in particular to a method, device and equipment for determining underground medium velocity. Background Art

[0002] Ocean bottom node (OBN) seismic data acquisition is a marine seismic exploration technology that has emerged in recent years. OBN is a multi-component seismometer laid on the seabed that can independently collect and record seismic signals. OBN can receive directional information of seismic data. The velocity model of the underground medium can be determined using the data collected by OBN. Then, the velocity model is used to image the seismic data. The higher the accuracy of the obtained velocity model, the higher the quality of the seismic data imaging.

[0003] In the prior art, a single-stage sub-source can be excited at the shot point, and seismic data can be collected using OBN. Then, based on the reciprocity theorem, the positions of the shot point and OBN are exchanged, a single-stage sub-source is excited at the exchanged shot point, and seismic simulation data is collected using the exchanged OBN. Then, the velocity model of the underground medium is determined using the upgoing waves of the seismic data and the seismic simulation data based on the Full Waveform Inversion (FWI) algorithm.

[0004] However, the accuracy of the velocity model obtained by the above method needs to be further improved. Summary of the invention

[0005] The present disclosure provides a method, device and apparatus for determining underground medium velocity, so as to improve the accuracy of the velocity model obtained in the prior art.

[0006] According to a first aspect of the present disclosure, a method for determining underground medium velocity is provided, the method comprising:

[0007] The seismic data generated by the excitation of a single-stage sub-source at a shot point is collected using a seabed node; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation;

[0008] Determine a dipole source and a zero-phase single-pole source according to the single-pole source; combine the dipole source and the zero-phase single-pole source to obtain a directional wavelet;

[0009] The position of the seafloor node and the position of the shot point are exchanged; and the exchanged seafloor node is used to collect seismic simulation data generated by the directional wavelet excited at the exchanged shot point;

[0010] A target velocity model is determined based on the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of seismic waves in underground media; and the upgoing wave represents seismic data collected from below the seafloor node.

[0011] According to a second aspect of the present disclosure, a device for determining underground medium velocity is provided, the device comprising:

[0012] An observation data acquisition unit is used to collect seismic data generated by exciting a single-stage sub-source at a shot point using a seabed node; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation;

[0013] A wavelet determination unit is used to determine a dipole source and a zero-phase single-stage source according to the single-stage source; and to combine the dipole source and the zero-phase single-stage source to obtain a directional wavelet;

[0014] A simulation data acquisition unit, used for exchanging the position of the seafloor node with the position of the shot point; and using the exchanged seafloor node to acquire seismic simulation data generated by exciting the directional wavelet at the exchanged shot point;

[0015] A velocity determination unit is used to determine a target velocity model based on the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of the seismic wave in the underground medium; and the upgoing wave represents the seismic data received from below the seabed node.

[0016] According to a third aspect of the present disclosure, an electronic device is provided, including a memory and a processor; wherein:

[0017] The memory is used to store computer programs;

[0018] The processor is used to read the computer program stored in the memory and execute the method for determining the underground medium velocity as described in the first aspect according to the computer program in the memory.

[0019] According to a fourth aspect of the present disclosure, a computer-readable storage medium is provided, wherein the computer-readable storage medium stores computer execution instructions. When a processor executes the computer execution instructions, the method for determining the underground medium velocity as described in the first aspect is implemented.

[0020] According to a fifth aspect of the present disclosure, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the method for determining underground medium velocity as described in the first aspect.

[0021] The method, device, and equipment for determining the velocity of underground media provided by the present disclosure include: using seabed nodes to collect seismic data generated by exciting a single-stage sub-source at a shot point; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation; determining a dipole source and a zero-phase single-stage sub-source according to the single-stage sub-source; combining the dipole source and the zero-phase single-stage sub-source to obtain a directional sub-wave; exchanging the position of the seabed node and the position of the shot point; and using the exchanged seabed node to collect seismic simulation data generated by exciting the directional sub-wave at the exchanged shot point; determining a target velocity model according to the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of seismic waves in the underground medium; and the upgoing wave represents the seismic data collected from below the seabed node. In the method, device, and equipment for determining the velocity of underground media provided by the present solution, the single-stage sub-source can be processed and a directional sub-wave with directional characteristics can be obtained. The seismic simulation data of the directional wavelet excited at the shot point is collected by using the seabed node, and the velocity model is determined by using the seismic simulation data and the upgoing waves separated from the collected seismic data. This solution can improve the accuracy of the obtained velocity model. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 A schematic flow chart of a method for determining underground medium velocity according to an exemplary embodiment of the present disclosure;

[0024] Figure 2 A single-level sub-source wave field snapshot is shown as an exemplary embodiment of the present disclosure;

[0025] Figure 3 A dipole source wave field snapshot is shown for an exemplary embodiment of the present disclosure;

[0026] Figure 4 A snapshot of a directional sub-wave field is shown as an exemplary embodiment of the present disclosure;

[0027] Figure 5 A schematic diagram of upgoing waves and downgoing waves in seismic data shown as an exemplary embodiment of the present disclosure;

[0028] Figure 6 A schematic diagram of an upgoing wave field record and a downgoing wave field record in seismic data shown in an exemplary embodiment of the present disclosure;

[0029] Figure 7 A schematic diagram of wave field recording generated by exciting a single-stage sub-source at a shot point after exchange, showing an exemplary embodiment of the present disclosure;

[0030] Figure 8 A schematic diagram of wave field recording for generating directional wavelets by exciting directional wavelets at exchanged shot points is shown as an exemplary embodiment of the present disclosure;

[0031] Fig. 9 A schematic flow chart of a method for determining underground medium velocity according to another exemplary embodiment of the present disclosure;

[0032] Fig.10 A schematic diagram of a first velocity model when simulating seismic data and an initial velocity model when simulating seismic simulation data shown in an exemplary embodiment of the present disclosure;

[0033] Fig.11 A schematic diagram of a velocity model obtained from a single-stage sub-source and a directional sub-wavelet, respectively, is shown as an exemplary embodiment of the present disclosure;

[0034] Fig.12 A structural diagram of a device for determining underground medium velocity according to an exemplary embodiment of the present disclosure;

[0035] Fig.13 The present invention is a structural diagram of an electronic device according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0036] Ocean bottom node (OBN) seismic data acquisition is a marine seismic exploration technology that has emerged in recent years. OBN is a multi-component seismometer laid on the seabed that can independently collect and record seismic signals. OBN can receive directional information of seismic data. The velocity model of the underground medium can be determined using the data collected by OBN. The velocity model is mainly used for seismic data imaging. The higher the accuracy of the obtained velocity model, the higher the quality of seismic data imaging. In the prior art, a single-stage sub-source can be excited at the shot point, and seismic data can be collected using OBN. Then, based on the reciprocity principle, the positions of the shot point and OBN are exchanged, a single-stage sub-source is excited at the exchanged shot point, and seismic simulation data is collected using the exchanged OBN. OBN can receive directional information of seismic data, so that the collected seismic data can be separated into upgoing waves and downgoing waves. The downgoing wave has a smaller offset distance to penetrate the stratum than the upgoing wave because it has been reflected by the free surface of the seawater. Therefore, the velocity model of the underground medium is usually determined based on the upgoing waves of seismic data and seismic simulation data and the Full Waveform Inversion (FWI) algorithm.

[0037] However, the accuracy of the velocity model obtained by the above method needs to be further improved.

[0038] In order to solve the above technical problems, the solution provided by the present disclosure can use the seabed node to collect seismic simulation data of directional sub-waves with directional characteristics excited at the shot point, and use the seismic simulation data and the upgoing waves separated from the collected seismic data to determine the velocity model, which can improve the accuracy of the velocity model.

[0039] The following specific embodiments are used to describe in detail the technical solution of the present invention and how the technical solution of the present invention solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0040] Figure 1 The present invention is a flowchart of a method for determining underground medium velocity according to an exemplary embodiment of the present invention.

[0041] like Figure 1 As shown, the method for determining the underground medium velocity provided in this embodiment includes:

[0042] Step 101, using the seabed node to collect seismic data generated by exciting a single-stage sub-source at a shot point; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation.

[0043] The method provided in the present disclosure may be executed by an electronic device with computing capability, such as a computer, etc. The electronic device may acquire seismic data collected by using a seafloor node.

[0044] Specifically, shot points can be set at multiple locations on the sea surface. Seabed nodes can be placed at multiple locations on the seabed. Single-stage sub-sources can be excited in sequence at multiple shot points, and seismic data can be collected using multiple seabed nodes.

[0045] Among them, the seismic data are seismic waves generated by exciting a single-stage sub-source.

[0046] Among them, the energy of a single-stage sub-source is uniform in all radiation directions at the moment of excitation. Figure 2 The figure shows a snapshot of the wave field of a single-stage sub-source, where both the horizontal and vertical axes represent positions.

[0047] Step 102, determining a dipole source and a zero-phase single-pole source based on the single-pole source; combining the dipole source and the zero-phase single-pole source to obtain a directional wavelet.

[0048] Specifically, the single-pole sub-source can be processed to obtain the dipole sub-source. Figure 3The figure shows a snapshot of the wave field of a dipole source. The horizontal and vertical axes both represent positions. A dipole source has the property that the longitudinal radiation energy is enhanced while the transverse radiation energy is weakened.

[0049] Specifically, the single-stage sub-source can be processed to obtain a zero-phase single-stage sub-source.

[0050] Specifically, the obtained dipole source and the zero-phase single-pole sub-source can be combined to obtain a directional sub-wave.

[0051] For example, a dipole source and a zero-phase single-pole source can be added together to obtain a directional wavelet, such as Figure 4 The figure shows a snapshot of the wave field of a directional wavelet obtained by adding a dipole source and a zero-phase single-stage source. The horizontal and vertical axes both represent positions. The directional wavelet has the directional characteristic of strengthening the downward radiation energy and eliminating the upward radiation energy. This characteristic can be used to better match the upgoing or downgoing waves in the seismic data.

[0052] Step 103, the position of the seafloor node and the position of the shot point are exchanged; and the exchanged seafloor node is used to collect seismic simulation data generated by the directional wavelet excited at the exchanged shot point.

[0053] Specifically, the position of the seabed node and the position of the shot point can be exchanged according to the reciprocity theorem. The multiple shot points after exchange and the multiple seabed nodes after exchange can be simulated by using simulation software. Further, the directional sub-waves are sequentially excited at the multiple shot points after exchange, and the seismic simulation data are collected using the multiple seabed nodes after exchange, that is, the seismic simulation data generated by the directional sub-waves excited at the seabed shot point position are collected at the sea surface position. For example, the simulation software can be GeoEast software.

[0054] Among them, GeoEast is an integrated software system for seismic data processing and interpretation collaboration with unified data platform, unified display platform, unified development platform and the ability to dynamically assemble systems.

[0055] Step 104, determining a target velocity model based on the upgoing waves of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of seismic waves in the underground medium; the upgoing waves represent seismic data collected from below the seafloor node.

[0056] Specifically, Figure 5 As shown in , the shot points are distributed on the sea surface, and the seabed nodes are distributed under the sea surface. The seabed nodes can be used to collect seismic data of the source excited at the shot points. The seismic data includes upgoing waves and downgoing waves. Figure 5The dotted line path shows that the seismic data collected from above the seafloor node after being reflected by the sea surface is the down-going wave in the seismic data. The down-going wave can be expressed as d(x, t i ), where x represents the position of the shot point, t i represents the sampling time, i represents the sampling sequence of the seafloor node, i=1,2,3…n. n is the total number of samples of single-channel data. Single-channel data refers to the sampling data of the seafloor node for one shot point.

[0057] Similar, such as Figure 5 The solid line path shows that the seismic data collected from below the seafloor node without reflection from the sea surface is the upgoing wave in the seismic data. The upgoing wave can be expressed as u(x, t i ), where x represents the position of the shot point, t i represents the sampling time, i represents the sampling sequence of the seafloor node, i=1,2,3…n. n is the total number of samples of single-channel data. Single-channel data refers to the sampling data of the seafloor node for one shot point.

[0058] Specifically, GeoEast software can be used to separate upgoing waves from seismic data.

[0059] Specifically, Figure 6 The left figure in the middle shows the upgoing wave field record in the seismic data, where the horizontal axis represents the shot point position and the vertical axis represents the sampling time of the seabed node. Figure 6 The middle right figure shows the downgoing wave field record in the seismic data, where the horizontal axis represents the shot point position and the vertical axis represents the sampling time of the seabed node.

[0060] Specifically, the upgoing waves of seismic data and seismic simulation data may be used to perform FWI, thereby obtaining a target velocity model of the propagation velocity of seismic waves in underground media.

[0061] like Figure 7 Shown is the wavefield record generated by exciting a single-stage sub-source at the exchanged shot point.

[0062] like Figure 8 The middle left figure shows the wave field record generated by exciting a directional wavelet at the exchanged shot point. The directional wavelet is obtained by adding a dipole source and a zero-phase single-stage source. The horizontal axis represents the position of the exchanged shot point, and the vertical axis represents the sampling time of the seafloor node.

[0063] like Figure 8The middle right figure shows the wave field record generated by exciting the directional wavelet at the exchanged shot point. The directional wavelet is obtained by subtracting the dipole source and the zero-phase monopole source. The horizontal axis represents the position of the exchanged shot point, and the vertical axis represents the sampling time of the seafloor node. Specifically, this scheme can obtain the directional wavelet by combining the zero-phase monopole source and the dipole source. Figure 6 , Figure 7 ,as well as Figure 8 It can be seen that using directional sub-waves as the source to simulate the up- and down-going wave fields separately can better match the up- and down-going wave field records than a single-stage sub-source.

[0064] After obtaining the target velocity model, since the target model represents the propagation velocity of seismic waves in the underground medium, the target velocity model can be displayed to facilitate users to view the propagation velocity of seismic waves in the underground medium. Electronic equipment can automatically perform oil and gas exploration based on the target velocity model. Users can also manually perform oil and gas exploration based on the target velocity model.

[0065] After obtaining the target velocity model, seismic data images can be generated based on the target velocity model and seismic data, and then oil and gas exploration can be performed automatically or manually based on the seismic data images. The higher the accuracy of the velocity model, the higher the quality of the generated seismic data images, which is more conducive to oil and gas exploration.

[0066] The method for determining the velocity of underground media provided by the present disclosure includes: using seabed nodes to collect seismic data generated by exciting a single-stage sub-source at a shot point; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation; determining a dipole source and a zero-phase single-stage sub-source according to the single-stage sub-source; combining the dipole source and the zero-phase single-stage sub-source to obtain a directional sub-wave; exchanging the position of the seabed node and the position of the shot point; and using the exchanged seabed node to collect seismic simulation data generated by exciting the directional sub-wave at the exchanged shot point; determining a target velocity model according to the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of seismic waves in underground media; and the upgoing wave represents the seismic data collected from below the seabed node. In the method adopted by the present disclosure, the single-stage sub-source can be processed and a directional sub-wave with directional characteristics can be obtained. Using the seabed node to collect seismic simulation data that excites the directional sub-wave at the shot point, and using the seismic simulation data and the upgoing wave separated from the collected seismic data to determine the velocity model. By adopting the method provided in the present disclosure, the accuracy of the velocity model can be improved.

[0067] Fig. 9 The present invention is a flowchart of a method for determining underground medium velocity according to another exemplary embodiment of the present invention.

[0068] like Fig. 9 As shown, the method for determining the underground medium velocity provided in this embodiment includes:

[0069] Step 901, using the seabed node to collect seismic data generated by exciting a single-stage sub-source at a shot point; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation.

[0070] Specifically, the principle and implementation of step 901 are similar to those of step 101 and will not be described in detail.

[0071] In one possible implementation, the single-stage sub-source is a seismic longitudinal wavelet.

[0072] Step 902, determine the first derivative parameter of the single-stage sub-source in the vertical direction, and determine the first derivative parameter to be a dipole source; determine the second derivative parameter of the single-stage sub-source with respect to time, and determine the second derivative parameter to be a zero-phase single-stage sub-source.

[0073] Specifically, the formula for the first derivative parameter of a single-stage sub-source in the vertical direction is as follows:

[0074]

[0075] Among them, f represents the wave field generated by a single-stage sub-source; x0 represents the position of the wave field generated by a single-stage sub-source; iz represents the increment in the z direction; and the z direction represents the vertical direction.

[0076] Specifically, the first derivative parameter may be determined as a dipole source.

[0077] Specifically, the formula for the second derivative parameter of a single-stage sub-source with respect to time is as follows:

[0078]

[0079] Among them, f represents the wave field generated by a single-stage sub-source; x0 represents the position of the wave field generated by a single-stage sub-source; it represents the increment in time t.

[0080] Specifically, the second derivative parameter can be determined as a zero-phase single-stage sub-source.

[0081] Step 903, combining the dipole source and the zero-phase single-pole sub-source to obtain a directional sub-wave.

[0082] Specifically, this solution does not limit the combination of the dipole source and the zero-phase monopole sub-source. For example, the dipole source and the zero-phase monopole sub-source can be added together, or the dipole source and the zero-phase monopole sub-source can be subtracted.

[0083] Specifically, this scheme obtains zero-phase single-stage sub-sources and dipole sources based on conventional single-stage sub-sources, which can not only obtain source wavelets with the same and different energies in different directions of space, but also combine the two wavelets to form new wavelets, enriching the choice of wavelets in OBN FWI.

[0084] Step 904, swapping the position of the seabed node with the position of the shot point.

[0085] Specifically, the position of the seabed node and the position of the gun point can be exchanged according to the reciprocity theorem.

[0086] Repeat the following process until the residual error between the upgoing wave and the seismic simulation data is less than a first preset threshold or the number of iterations is greater than a second preset threshold:

[0087] Step 905 , based on the current velocity model, using the exchanged seafloor nodes to collect seismic simulation data generated by exciting directional wavelets at the exchanged shot points.

[0088] Specifically, a simulation model can be established using simulation software according to the current velocity model, and multiple shot points after exchange and multiple seabed nodes after exchange can be simulated in the simulation model.

[0089] Specifically, in the first repetition process, the current velocity model may be a preset initial velocity model. The initial velocity model is a velocity model preset according to actual conditions. For example, if the seismic data is obtained by simulation software, the seismic data may be based on Fig.10 The first velocity model is shown in the left figure. The first velocity model can be smoothed to obtain the initial velocity model. The initial velocity model is as follows: Fig.10 As shown in the middle right figure. In the velocity model, both the horizontal and vertical axes represent positions.

[0090] Specifically, simulation software is used to simulate the sequential excitation of directional sub-waves at multiple shot points after exchange, and seismic simulation data are collected using multiple nodes after exchange.

[0091] Step 906, determining the residual between the upgoing wave and the seismic simulation data based on the upgoing wave and the seismic simulation data.

[0092] Specifically, FWI can be performed using upgoing waves of seismic data and seismic simulation data.

[0093] First, an objective function may be constructed based on the upgoing wave of the seismic data and the seismic simulation data to determine the residual between the upgoing wave of the seismic data and the seismic simulation data.

[0094] Among them, the formula of the constructed objective function is as follows:

[0095]

[0096] in, represents the residual between the upgoing wave of seismic data and the seismic simulation data; m represents the current velocity model; ρ represents the expression of the objective function; D represents the upgoing wave of seismic data; F(m) represents the seismic simulation data obtained based on the current velocity model.

[0097] Step 907: Determine the search direction parameter and search step length parameter of the current velocity model according to the residual.

[0098] Specifically, based on the constructed objective function, the velocity can be differentiated to obtain the gradient of the current velocity model, and then the search direction parameter and the search step size parameter of the current velocity model can be obtained.

[0099] Step 908, updating the current velocity model according to the search direction parameter, the search step size parameter and the current velocity model; wherein the model obtained when the residual is less than a first preset threshold or the number of iterations reaches a second preset threshold is the target velocity model.

[0100] Specifically, an update function can be constructed according to the search direction parameter, the search step parameter and the current speed model to update the current speed model. The update function is as follows:

[0101] m k+1 =m k +α k s k

[0102] Among them, m k Represents the current velocity model; α k Indicates the search direction parameter of the current velocity model; s k Indicates the search step size parameter of the current velocity model; m k+1 Represents the updated velocity model.

[0103] Specifically, if it is determined that the residual between the upgoing wave of the seismic data and the seismic simulation data is greater than the first preset threshold and the number of iterations has not reached the second preset threshold, the updated velocity model is used as the current velocity model for the next repetition process, and step 705 is continued until it is determined that the residual is less than the first preset threshold or the number of iterations reaches the second preset threshold, then the repetition process is terminated, and the velocity model obtained at this time is determined as the target velocity model.

[0104] Specifically, Fig.11 The figure on the right shows the target velocity model obtained by inversion based on the collected seismic simulation data of the excitation directional wavelet. The horizontal axis represents the spatial position, the vertical axis represents the sea depth, and different colors represent different velocity values.

[0105] Specifically, Fig.11 The left figure shows the velocity model obtained based on the collected seismic simulation data of the single-stage sub-source. The horizontal axis represents the spatial position, the vertical axis represents the sea depth, and different colors represent different velocity values.

[0106] Specifically, the collected seismic simulation data of the excited single-stage sub-source and the collected seismic simulation data of the excited directional sub-wave are compared; a large number of multiple waves exist in the collected seismic simulation data of the excited single-stage sub-source.

[0107] contrast Fig.10 From the left and right figures in , it can be seen that the inversion result obtained based on the directional wavelet has a more accurate result on the velocity interface.

[0108] Specifically, this scheme uses the reciprocity theorem to exchange the positions of sea surface shot points and seabed nodes in OBN data for directional wavelet FWI inversion, which can invert the upgoing wavefield data separately and obtain a more accurate velocity model update compared to the single-stage sub-source FWI, thereby obtaining a more accurate velocity model.

[0109] Step 909: Display the target velocity model so that the user can view the propagation velocity of seismic waves in the underground medium.

[0110] Specifically, the target velocity model can be displayed by simulation software so that the user can view the propagation velocity of seismic waves in the underground medium.

[0111] Fig.12 The present invention is a structural diagram of an apparatus for determining underground medium velocity according to an exemplary embodiment of the present invention.

[0112] like Fig.12 As shown, the underground medium velocity determination device 1200 provided by the present disclosure includes:

[0113] The observation data acquisition unit 1210 is used to collect seismic data generated by exciting a single-stage sub-source at a shot point using a seabed node; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation;

[0114] The wavelet determination unit 1220 is used to determine the dipole source and the zero-phase single-stage source according to the single-stage source; combine the dipole source and the zero-phase single-stage source to obtain a directional wavelet;

[0115] The simulation data acquisition unit 1230 is used to exchange the position of the seabed node and the position of the shot point; and use the exchanged seabed node to collect the seismic simulation data generated by the directional wavelet excited at the exchanged shot point;

[0116] The velocity determination unit 1240 is used to determine a target velocity model based on the upgoing waves of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of the seismic waves in the underground medium; the upgoing waves represent the seismic data received from below the seabed node.

[0117] The wavelet determination unit 1220 is specifically used to determine the first derivative parameter of the single-stage sub-source in the vertical direction, and determine the first derivative parameter as a dipole source;

[0118] Determine the second derivative parameter of the single-stage sub-source with respect to time, and determine the second derivative parameter as a zero-phase single-stage sub-source.

[0119] The velocity determination unit 1240 is specifically configured to repeatedly perform the following process until the residual error between the upgoing wave and the seismic simulation data is less than a first preset threshold or the number of iterations reaches a second preset threshold:

[0120] Based on the current velocity model, the exchanged seafloor nodes are used to collect seismic simulation data generated by directional wavelets excited at the exchanged shot points;

[0121] Determine the residual between the upgoing wave and the seismic simulation data according to the upgoing wave and the seismic simulation data;

[0122] According to the residual, the search direction parameter and the search step length parameter of the current velocity model are determined;

[0123] Update the current velocity model according to the search direction parameter, the search step size parameter and the current velocity model;

[0124] Among them, the model obtained when the residual is less than the first preset threshold or the number of iterations reaches the second preset threshold is the target speed model.

[0125] In one possible implementation, the single-stage sub-source is a seismic longitudinal wavelet.

[0126] The device 1200 for determining underground medium velocity also includes a display unit 1250 for displaying a target velocity model so that a user can view the propagation velocity of seismic waves in the underground medium.

[0127] Fig.13 The present invention is a structural diagram of an electronic device according to an exemplary embodiment of the present invention.

[0128] like Fig.13 As shown, the electronic device provided in this embodiment includes:

[0129] Memory 1301;

[0130] Processor 1302; and

[0131] Computer programs;

[0132] The computer program is stored in the memory 1301 and is configured to be executed by the processor 1302 to implement any of the above methods for determining the velocity of the underground medium.

[0133] This embodiment also provides a computer-readable storage medium on which a computer program is stored. The computer program is executed by a processor to implement any of the above methods for determining the velocity of an underground medium.

[0134] This embodiment also provides a computer program product, including a computer program, which, when executed by a processor, implements any of the above-mentioned methods for determining the velocity of an underground medium.

[0135] Those skilled in the art can understand that all or part of the steps of implementing the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, the steps of the above-mentioned method embodiments are executed; and the aforementioned storage medium includes: ROM, RAM, disk or optical disk and other media that can store program codes.

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining underground medium velocity, characterized in that: The method comprises: The seismic data generated by the excitation of a single-stage sub-source at a shot point is collected using a seabed node; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation; Determine a dipole source and a zero-phase single-pole source according to the single-pole source; combine the dipole source and the zero-phase single-pole source to obtain a directional wavelet; The position of the seafloor node and the position of the shot point are exchanged; and the exchanged seafloor node is used to collect seismic simulation data generated by the directional wavelet excited at the exchanged shot point; Determine a target velocity model according to the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of the seismic wave in the underground medium; the upgoing wave represents the seismic data collected from below the seafloor node; The step of determining a dipole source and a zero-phase single-stage sub-source according to the single-stage sub-source comprises: Determine the first derivative parameter of the single-stage sub-source in the vertical direction, and determine the first derivative parameter to be the dipole source; determine the second derivative parameter of the single-stage sub-source in time, and determine the second derivative parameter to be the zero-phase single-stage sub-source; The formula of the first derivative parameter of the single-stage sub-source in the vertical direction is as follows: (f(x_0))′=(f(x_0+iz)-f(x_0)) / iz Wherein, f represents the wave field generated by the single-stage sub-source; x_0 represents the position of the wave field generated by the single-stage sub-source; iz represents the increment in the z direction; and the z direction represents the vertical direction; The formula of the second derivative parameter of the single-stage sub-source with respect to time is as follows: (f_t(x_0))′=(f(x_0+it)-f(x_0)) / it Among them, f represents the wave field generated by the single-stage sub-source; x_0 represents the position of the wave field generated by the single-stage sub-source; it represents the increment in time t.

2. The method according to claim 1, characterized in that The step of determining a dipole source and a zero-phase single-stage sub-source according to the single-stage sub-source comprises: Determine a first derivative parameter of the single-stage sub-source in a vertical direction, and determine the first derivative parameter as the dipole source; Determine a second derivative parameter of the single-stage sub-source with respect to time, and determine the second derivative parameter to be the zero-phase single-stage sub-source.

3. The method according to claim 1, characterized in that The method of using the exchanged seabed nodes to collect the seismic simulation data generated by exciting the directional wavelet at the exchanged shot points; and determining the target velocity model according to the upgoing waves of the seismic data and the seismic simulation data, comprises: Repeat the following process until the residual error between the upgoing wave and the seismic simulation data is less than a first preset threshold or the number of iterations reaches a second preset threshold: Based on the current velocity model, using the exchanged seafloor nodes to collect seismic simulation data for exciting the directional wavelet at the exchanged shot points; Determining a residual between the upgoing wave and the seismic simulation data according to the upgoing wave and the seismic simulation data; Determining a search direction parameter and a search step length parameter of the current velocity model according to the residual; updating the current speed model according to the search direction parameter, the search step size parameter and the current speed model; The model obtained when the residual is less than a first preset threshold or the number of iterations reaches a second preset threshold is the target speed model.

4. The method according to any one of claims 1 to 3, characterized in that The single-stage sub-source is a seismic longitudinal wavelet.

5. The method according to any one of claims 1 to 3, characterized in that: The method further comprises: The target velocity model is displayed to allow a user to view the propagation velocity of seismic waves in the subsurface medium.

6. A device for determining underground medium velocity, characterized in that: The device comprises: An observation data acquisition unit is used to collect seismic data generated by exciting a single-stage sub-source at a shot point using a seabed node; wherein the energy of the single-stage sub-source is uniform in all radiation directions at the time of excitation; A wavelet determination unit is used to determine a dipole source and a zero-phase single-stage source according to the single-stage source; and to combine the dipole source and the zero-phase single-stage source to obtain a directional wavelet; A simulation data acquisition unit, used for exchanging the position of the seafloor node with the position of the shot point; and using the exchanged seafloor node to acquire seismic simulation data generated by exciting the directional wavelet at the exchanged shot point; A velocity determination unit, configured to determine a target velocity model according to the upgoing wave of the seismic data and the seismic simulation data; wherein the target velocity model is used to characterize the propagation velocity of the seismic wave in the underground medium; and the upgoing wave represents the seismic data received from below the seafloor node; The sub-wave determination unit is specifically used to determine the first derivative parameter of the single-stage sub-source in the vertical direction, and determine the first derivative parameter as the dipole source; determine the second derivative parameter of the single-stage sub-source in time, and determine the second derivative parameter as the zero-phase single-stage sub-source; The formula of the first derivative parameter of the single-stage sub-source in the vertical direction is as follows: (f(x_0))′=(f(x_0+iz)-f(x_0)) / iz Wherein, f represents the wave field generated by the single-stage sub-source; x_0 represents the position of the wave field generated by the single-stage sub-source; iz represents the increment in the z direction; and the z direction represents the vertical direction; The formula of the second derivative parameter of the single-stage sub-source with respect to time is as follows: (f_t(x_0))′=(f(x_0+it)-f(x_0)) / it Among them, f represents the wave field generated by the single-stage sub-source; x_0 represents the position of the wave field generated by the single-stage sub-source; it represents the increment in time t.

7. The device according to claim 6, characterized in that The wavelet determination unit is specifically used for: Determine a first derivative parameter of the single-stage sub-source in a vertical direction, and determine the first derivative parameter as the dipole source; Determine a second derivative parameter of the single-stage sub-source with respect to time, and determine the second derivative parameter to be the zero-phase single-stage sub-source.

8. An electronic device, characterized in that: comprising a memory and a processor; wherein, The memory is used to store computer programs; The processor is used to read the computer program stored in the memory and execute the method according to any one of claims 1 to 5 according to the computer program in the memory.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-executable instructions, and when the processor executes the computer-executable instructions, the method described in any one of claims 1 to 5 is implemented.

10. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the method described in any one of claims 1 to 5 is implemented.

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