阅读说明：本技术 一种水下垂直缆地震波干涉成像方法及装置 (Underwater vertical cable seismic wave interference imaging method and device ) 是由 陈学磊 王祥春 于 2021-10-19 设计创作，主要内容包括：本发明公开了一种水下垂直缆地震波干涉成像方法,所述方法包括：建立地质模型；选取若干个炮点中的两个炮点位置A和位置B；水下设置若干个检波器,将同一检波器接收到的位置A和位置B的两炮数据进行互相关运算；重复进行每个检波器的互相关运算,直至完成检波器域循环；获得一组干涉处理后的数据记录,进行叠加后得到以位置A模拟作为虚源,位置B作为模拟检波器的单道记录；完成炮域计算和共炮点道集,最后得到地质成像。本发明利用直达波与多次波,而不是将多次波作为噪声在处理过程中被滤除,而作为有效信息参与处理过程；通过构建虚震源,可以扩大数据量,因此能够获得更高质量的剖面成像。(The invention discloses an underwater vertical cable seismic wave interference imaging method, which comprises the following steps: establishing a geological model; selecting two shot point positions A and B in the plurality of shot points; arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed; obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition; and completing shot domain calculation and shot point gather sharing, and finally obtaining geological imaging. The invention utilizes direct waves and multiples, rather than filtering the multiples as noise in the processing process, and participates in the processing process as effective information; by constructing virtual sources, the amount of data can be enlarged, and therefore higher quality sectional imaging can be obtained.)

1. An underwater vertical cable seismic wave interference imaging method is characterized by comprising the following steps:

establishing a geological model, and forward modeling to obtain a common shot gather;

selecting two shot point positions A and B in the plurality of shot points;

arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed;

obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition;

completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector;

calculating to obtain a common shot gather taking the position A as a virtual source;

and obtaining geological imaging after calculation processing.

2. The method of interferometric imaging of a submarine vertical cable seismic wave according to claim 1, wherein the shot point is placed at the surface of the water outside the vertical direction of the vertical cable and the geophones are located on the vertical cable.

3. An underwater vertical cable seismic interference imaging method as claimed in claim 1, wherein the two shot data at position a and position B include direct and multiple signals.

4. A submarine vertical cable seismic wave interference imaging method according to claim 3, wherein the position a simulation is used as a virtual source, the position B is used as a single-pass record of a simulated geophone, that is, a direct wave signal from a shot point at the position B to the geophone is detected, and the direct wave signal is eliminated from a seismic wave signal reflected again to the geophone after the shot point signal at the position a is reflected to the position B through a stratum and is used as signal data of the single-pass record.

5. An underwater vertical cable seismic interference imaging method as claimed in claim 2, wherein said geophones are mounted on the vertical cable at equal or unequal intervals; the position of the vertical cable in the water is below 100m of the water surface.

6. The method for interference imaging of underwater vertical cable seismic waves of claim 1, wherein the number of shots is 10 to 350; the distance between the shot points is 6-50 m.

7. The underwater vertical cable seismic wave interference imaging method of claim 1, wherein the number of said geophones is 10-95; the distance between adjacent detectors is 5-30 m.

8. An electronic device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, wherein the processor when executing the program performs the steps of the method for underwater vertical cable seismic interference imaging according to any of claims 1 to 7.

9. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the computer program when executed by a processor implements the steps of the method for underwater vertical cable seismic wave interference imaging according to any one of claims 1 to 7.

10. A computer program product comprising a computer program, wherein the computer program when executed by a processor implements the steps of the method for underwater vertical cable seismic interference imaging according to any one of claims 1 to 7.

Technical Field

The invention relates to a geological exploration technology, in particular to an underwater vertical cable seismic wave interference imaging method and device.

Background

With the development of exploration technology, the emphasis of oil and gas exploration is gradually shifting from land to sea, and it is well known that the most effective and accurate exploration method for natural gas hydrates is seismic exploration. In marine seismic exploration, the application of various marine seismic observation systems such as a streamer, a submarine cable and a submarine seismograph and various marine seismic data processing methods are increasingly mature, however, the mature observation systems have limited detection capability for some special regions, cannot achieve the optimal imaging effect, and have some defects.

In recent years, VCS (Vertical Cable Seismic system) has attracted wide attention from geophysicists at home and abroad due to its characteristics of wide frequency, wide angle, and easy recognition of multiples. The technology is usually used for local structure detection and imaging of a stratum with a large inclination angle, is an effective supplement of other seismic detection methods, and is an indispensable link in high-precision marine seismic exploration.

Vertical cables were first used in the army anti-submarine strategic installations in the united states, and the earliest vertical cable seismic surveys in the world occurred in the gulf of mexico in 1987, with a total of three vertical cables launched. The purpose of vertical cable seismic exploration for the first time is to solve the problem of imaging of lithologic reservoirs of geological structures under the sea area. In 1989, the vertical cable seismic data acquisition system was used in the near sea at a water depth of about 600 meters in louisiana, usa, where 12 vertical cables were launched and 180 lines of guns were laid out on the sea surface, each gun being monitored in real time by a telemetry system on the survey vessel. In 1992, 6 vertical cables were launched into the water to image the underground rock formations with water depth over 1000m in the gulf of mexico, and the same prestack depth migration imaging processing technology was performed on the data collected by the streamers in the same region, so that the imaging accuracy of the vertical cable data was found to be significantly higher than that of the streamer data. In 1997, Andersonden et al also acquired seismic data in the gulf of Mexico with streamers and vertical cables, and processed the acquired data under the same conditions, and the migration technology all used the prestack depth migration technology, and it was known that vertical cable data can present more complex micro geological structure information than streamer data through a research method of control variables. In 1998, guinaraes et al were performing forward modeling on salt dome geological structure models and simulated reception by vertical cable seismic acquisition systems. Meanwhile, the simulated up-and-down wave field of the vertical cable is combined in the processing process, and finally, some advantages and disadvantages of the vertical cable observation system are proved.

With the continuous progress of the vertical cable technology in foreign seismic exploration, a plurality of domestic scholars gradually develop trial production and research of the vertical cable seismic exploration technology in recent years, and China just starts to develop vertical cable instruments.

In 1998, HuangBiming translated Ward' vertical cable related article, mainly introduced Fuji experiments on seismic acquisition feasibility. In 2015, heroic and other people analyzed the ray illumination of the vertical cable observation system, and basis is provided for the design of the optimal vertical cable observation system. In 2015, experimental tests by Bian et al show that a high-resolution and high-fidelity underground structure model can be provided by adopting a multi-scale full waveform inversion technology and the combination of low-frequency data and a multi-vertical cable acquisition system. In 2015, yangxinghui et al performed separation of up-going and down-going wavefields on vertical cable data using the method of Radon transform. In 2018, Anzhenhang et al designed corresponding observation systems for single vertical cables and multiple vertical cables, and provided a series of beneficial conclusions for improving the imaging effect of the vertical cables from the collection angle. At present, although China is still in the starting stage in the aspect of vertical cable seismic exploration, the Guangzhou oceanic geological survey bureau develops trial production of vertical cable seismic exploration and development of related vertical cable systems in the south China sea area. In 2019, a mirror image offset method is used by Huwang, multiple waves in actual VCS exploration data are used as effective waves to be imaged by a conventional method, and the purpose is to process a finer vertical cable imaging section.

Seismic interferometry is developed to date and mainly has three specific forms, namely correlation type seismic interferometry, convolution type seismic interferometry and deconvolution type seismic interferometry.

In 1968, Claerbout utilized the seismic records obtained by horizontal layered medium underground blasting, and the transmission information from the bottom was subjected to autocorrelation operation to obtain a Green function describing the field-source relationship, and the method was named as 'sunlight imaging'. Claerbout opens the door of the seismic interference method and becomes a pioneer of the seismic interference technology in the geophysical industry. The conclusion is not only applicable to the self-excitation and self-reception condition, but also can be applied to the cross-correlation operation of the seismic signals recorded by two different detectors, so that a new seismic signal can be obtained. The teaching of Claerbout concluded that this conclusion could be generalized to three-dimensional anisotropic media as well, however no evidence is given. In 2000, Schuster professor imaged the information of the underground structure by performing fixed phase analysis on the seismic data after the offset, and formally used the term seismic wave interferometry in a conference article published by Schuster in 2001. In 2002, in order to prove the hypothesis of Claerbout, Wapenaar et al, combined with Green's theorem, demonstrated that Wapenaar provides a mathematical and physical basis for the development of seismic interferometry, and since then, the future development of seismic interferometry is quite clear. In 2004, Calvert et al proposed a virtual seismic source method, which promoted the practical application of coherent imaging technology, and this method could convert the reference plane VSP data into single well profile data. Subsequently, the method is gradually applied to various fields such as passive source interference imaging, bulk wave interference imaging, surface wave interference imaging and the like. In 2009, the Schuster professor combines the prior human to summarize the imaging of the Seismic interference method to complete a series interference measurement book, wherein the book has a certain description of the Seismic interference method in VSP and various Seismic exploration and observation systems.

Meanwhile, in China, a plurality of scholars deeply research the seismic interference method, wherein the application research on natural seismology is earlier and better effect is obtained, and the Wu Shi Nu professor team and the Chen national gold professor team and the like research and learn the virtual seismic source method. In 2009, often asahi discusses the relationship of seismic coherence migration to data self-reference migration in terms of active sources. In 2011, wushilian studied coherent imaging of subsurface seismographs in complex overburden based on virtual source estimation. In the same year, george discusses the effect of wavefield separation on virtual source imaging quality. People of Tooseita et al establish an actual geological model in the article and summarize a flow for intervention processing. In 2012, niuma analyzes the application principle of the seismic interference method in VSP in the parent student's paper, and specifically describes the mathematical and physical principles of the three interference methods, which proves that the reconstruction of the wave field can be realized by applying the seismic interference method. Since multiples are the active ingredient in the interferometric process, seismic interferometric processing expands the illumination range underground, as compared to conventional VSP primary imaging. Often asa et al also have studied seismic coherence migration in the VSP field.

In the aspect of research of seismic interference method imaging, in 2004, Schuster unifies the sunlight illumination method of Claerbout into an interference imaging method and shows the advantages of the method from the perspective of practical application. In 2006, Fink studied reverse acoustic imaging under complex environmental conditions, and investigated the effects of the length of the reverse time window and the bandwidth of the reverse time signal. In the same year, Willis and Homby respectively utilize the reverse time acoustic wave principle and the interference imaging principle to realize the salt dome flank imaging of Walkaway VSP data. In 2006, Xiao realizes salt dome flank imaging of converted transverse waves by using a seismic interference method; hohl and Mateeva realize the imaging of passive source reflection waves of submarine cable data through a seismic interference method. The Shragge realizes the interference migration under the shot gather record by using the actually monitored remote seismic data volume; berkhout and Vershuur convert multiple noise into primary noise by using a seismic interference method, and perform migration imaging, so that good effect is achieved. In 2006, Borcea studied coherent imaging techniques under random media conditions; yu and Schuster studied migration imaging of cross-correlation gathers of the IVSP inverse vertical seismic profile data volume; and performing comparative analysis on the reverse time migration result and the interference migration result of the common depth domain seismic data volume by using Zhou, and finding that the reverse time migration result and the interference migration result can well avoid the influence of the overlying complex stratum. In 2007, He achieved 3D wave equation interference migration of free surface multiples in vertical seismic profile VSP data volumes. The Draganov utilizes the environmental noise recorded by the detectors under the given arrangement to extract the reflected wave information and perform offset imaging on the reflected wave information, so that a better effect is achieved.

In 2016, Olivier Carrie performed conventional seismic processing and seismic interference processing, respectively, on actual data in a sea area in the gulf of Mexico, and correlation type seismic interference was mainly used in the article. The comparison of the underground PP reflection coefficient images obtained by comparing the two processing methods shows that the seismic interference technology is still applicable to marine seismic exploration.

In marine seismic surveys, the receiver seafloor useful information is limited because receivers are expensive, relatively small in number compared to land surveys, and therefore, the received signals are used as fully as possible.

In a conventional processing method, as shown in fig. 1, which is a schematic diagram of marine vertical cable seismic exploration, multiples are identified as noise and filtered out in the imaging process, however, the multiples still contain a large amount of useful information, and the underground structure information can still be obtained by processing the data; meanwhile, in the exploration of the ocean vertical cable, a detector needs to be hung on one cable at the beginning of design, and the acquisition mode is as follows: hanging a heavy object at the bottom of the cable, and sinking to the seabed; a floating ball is suspended at the top and floats on the sea surface; the detectors are mounted on the cable at equal or unequal intervals. In the process of collecting, the mounting mode is influenced by ocean currents, and the position of the detector in water is inaccurate, so that secondary positioning and other work are needed in post-processing.

Disclosure of Invention

The invention aims to provide an underwater vertical cable seismic wave interference imaging method which can utilize direct waves and multiple waves to enlarge data volume by constructing a virtual seismic source so as to obtain higher-quality section imaging; the imaging process is simple and quick, and the result is more accurate.

In order to achieve the above object, the present invention provides an underwater vertical cable seismic wave interference imaging method, including:

establishing a geological model, and forward modeling to obtain a common shot gather;

selecting two shot point positions A and B in the plurality of shot points;

arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed;

obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition;

completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector;

calculating to obtain a common shot gather taking the position A as a virtual source;

and obtaining geological imaging after calculation processing.

In one embodiment of the invention, the shot point is located on the water surface other than vertically on the vertical cable and the geophones are located on the vertical cable.

In one embodiment of the present invention, the two shot data at location a and location B include direct and multiple signals.

In an embodiment of the invention, the position a is simulated as a virtual source, the position B is recorded as a single track of a simulated geophone, that is, a direct wave signal from a shot point at the position B to the geophone is detected, and a seismic wave signal reflected to the geophone again after the shot point signal at the position a is reflected to the position B through a stratum is used for eliminating the direct wave signal and is used as signal data of the single track recording.

In one embodiment of the invention, the geophones are mounted on the vertical cable at equal or unequal intervals; the position of the vertical cable in the water is below 100m of the water surface.

In one embodiment of the invention, the number of shots is 10-350; the distance between the shot points is 6-50 m.

In one embodiment of the present invention, there are 10-95 detectors; the distance between adjacent detectors is 5-30 m.

The more the number of the hydrophones is, the more accurate the obtained result is, but in the actual exploration process, the number of the hydrophones is limited, and a few or dozens of hydrophones are good; the method of the invention can not only process the condition of a large number of detectors, but also can still image when the number of the detectors is small. In actual marine exploration, the distance between the cannons is generally 12.5 meters, and a large cannon distance is still applicable; the geophones may be deep during actual settling, depending on the actual water depth.

The invention also provides electronic equipment which comprises a memory, a processor and a computer program which is stored on the memory and can be run on the processor, wherein the processor executes the program to realize the steps of any one of the underwater vertical cable seismic wave interference imaging methods.

The invention also provides a non-transitory computer readable storage medium having stored thereon a computer program which, when executed by a processor, performs the steps of any of the above-described methods for underwater vertical cable seismic wave interference imaging.

The invention also provides a computer program product comprising a computer program which, when executed by a processor, implements the steps of any of the above-described methods of underwater vertical cable seismic wave interference imaging.

Compared with the prior art, the underwater vertical cable seismic wave interference imaging method applies the seismic interference method to the ocean vertical cable seismic exploration, utilizes direct waves and multiple waves, but not filters the multiple waves as noise in the processing process and participates in the processing process as effective information; by constructing a virtual seismic source, the data volume can be enlarged, so that higher-quality section imaging can be obtained; the detector on the vertical cable is hung on the cable, the position of the detector is influenced by water flow and is inaccurate, the conventional method needs secondary positioning and other work in the later period, and the invention can carry out calculation imaging without an accurate observation system when processing data, and the imaging result is displayed, so that the method has higher accuracy; compared with the conventional processing method, the method has the advantages of simple and quick imaging and relatively accurate result, and can provide reliable reference for subsequent processing explanation and the like.

Drawings

FIG. 1 is a schematic illustration of a marine vertical cable seismic survey according to the background of the invention;

FIG. 2 is a schematic diagram of signal paths of an underwater vertical cable seismic wave interference imaging method according to the invention;

FIG. 3 is a flow chart of an underwater vertical cable seismic wave interference imaging method according to the invention;

FIG. 4 is a schematic diagram of a vertical cable seismic survey model according to an embodiment of the invention;

FIG. 5 is a forward seismic recording map according to an embodiment of the invention;

FIG. 6 is a diagram of direct wave seismic records obtained after wavefield separation according to one embodiment of the present invention;

FIG. 7 is a diagram of direct wave and multitap seismic records obtained after wavefield separation according to one embodiment of the present invention;

FIG. 8 is a diagram of a virtual source record resulting from a calculation process according to an embodiment of the invention;

FIG. 9 is a cross-sectional view of a time domain overlay resulting from processing of a virtual source record in accordance with an embodiment of the present invention;

FIG. 10 is a primary raw seismic signal record according to an embodiment of the present invention;

FIG. 11 is a diagram of direct wave signals after wavefield separation according to an embodiment of the invention;

FIG. 12 is a diagram of a multiple signal after wavefield separation according to an embodiment of the present invention;

FIG. 13 is a virtual source record obtained by processing actual data according to an embodiment of the present invention;

FIG. 14 is a cross-sectional view of a data-processed virtual source record overlay in accordance with one embodiment of the present invention;

FIG. 15 is a CMP104 pick-up velocity profile according to an embodiment of the present invention;

FIG. 16 is a velocity field map created after virtual source recording velocity analysis according to an embodiment of the present invention;

FIG. 17 is a schematic structural diagram of an electronic device according to an embodiment of the invention;

description of the main reference numerals:

1701-a processor; 1702-a memory; 1703-a communication bus; 1704 — a communication interface;

wherein: in fig. 10-13, the ordinate is time in ms and the abscissa is trace; the abscissa of fig. 9 and 14 is cmp and the ordinate is time in s.

Detailed Description

The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.

Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.

As shown in fig. 2 to 17, the underwater vertical cable seismic wave interference imaging method according to the preferred embodiment of the invention.

In the process of processing by the underwater vertical cable seismic wave interference imaging method, the data is processed by constructing the virtual seismic source. FIG. 2 is a schematic diagram of the vertical cable seismic interference imaging method of the present invention in VCS exploration. Firstly, exchanging shot and inspection points in VCS exploration according to reciprocity theorem, wherein in actual VCS exploration, PQ is a shot point positioned below a sea surface, S is a detection point positioned on a vertical cable, in figure 2, the shot and inspection points are exchanged, after the S point is excited, a P point firstly receives a direct wave signal, then a reflection is generated on a sea-air interface, the wave continues to propagate downwards, the emission is generated after the interface is met, the detection point of the Q point receives a reflected wave, the shot and inspection are exchanged, wave field information received by the PQ can be considered as that the PQ is excited respectively, and the S point receives the PQ. After the direct wave and the multiple wave received by the PQ are subjected to interference processing, the common path PS segment is eliminated, and then the virtual source record with P as a shot point and Q as a detection point can be obtained.

According to the processing principle, the position of the hydrophone does not influence the generation of virtual source records during processing, so that the method does not need accurate observation system information during data processing, namely, the slight fluctuation of the position of the hydrophone does not influence the accuracy of the data; meanwhile, the method can also be used for simply and quickly imaging and provides reference for subsequent accurate processing explanation.

In other conventional seismic data processing methods, multiples are filtered out as noise, however, in practice, the multiples still contain useful information reflecting the subsurface structure. As can be seen from fig. 2, in the VCS exploration process, the direct wave and the multiple wave are processed to obtain a new virtual source record, and in this process, the multiple wave is used as a main object to participate in the processing, so that the information in the multiple wave is fully utilized.

In the virtual source record generated in fig. 2, the shot points are all located on the same datum plane, and in the acquired original data, the shot points are located on the sea surface, and the detectors are suspended on vertical cables in the water. Meanwhile, in the newly generated virtual source record, the position of the wave detection point is the same as that of the shot point, so that compared with the original data, the data of the wave detection point can be increased, the data volume can be increased, and more stratum reflection information and data can be provided for subsequent imaging.

The invention relates to a vertical cable seismic interference method processing flow: in the processing process, according to the principle method, the related processing is programmed, the following processing flow is formulated, the data processing is realized, and the obtained virtual source record is processed and imaged. The flow chart of the underwater vertical cable seismic wave interference imaging method is shown in FIG. 3: establishing a geological model, and forward modeling to obtain a common shot gather; selecting two shot point positions A and B in the plurality of shot points; arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed; obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition; completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector; calculating to obtain a common shot gather taking the position A as a virtual source; and obtaining geological imaging after calculation processing.

The processing flow of performing seismic interference method on the common shot gather to obtain the virtual source record is shown in fig. 3. The actual VCS exploration data is a common receiving point gather, so that preprocessing work needs to be carried out on the data in the early stage. If a new seismic record with the position A as a virtual seismic source and the position B as a geophone point is to be obtained, seismic traces with the position A as a geophone corresponding to each shot and seismic signals with the position B as a geophone corresponding to the same shot record need to be extracted and correlated until the extraction and correlation of the seismic signals of all the shots for the B geophone and the A geophone are completed. The superposition of the signals of all the seismic traces of the correlation map results in a new seismic signal which can be interpreted as a seismic signal with position a as the source and position B as the detector. And then performing cross-correlation operation on the seismic signals received by the detectors at the positions A and other shot points by taking the position A as a virtual seismic source, and then stacking the seismic signals until the calculation of all the shot points is completed, so as to obtain a new virtual source seismic record taking A as a virtual source point and other shot points as virtual geophone points, and finally, completing the calculation of the virtual source points on all the shot points, so as to obtain virtual source records corresponding to all the shot points. After the virtual source record is obtained, the conventional processing such as dynamic correction, superposition and the like can be completed by using related processing software, so that imaging is realized.

In the embodiment of the invention, firstly, a geological model needs to be constructed, in order to better verify the application of the seismic interference method in VCS exploration, firstly, an actual exploration geological model is established, and a schematic diagram of a vertical cable seismic exploration model is shown in FIG. 4. In the model, four horizons, a horizontal seabed and two inclined interfaces are simulated in total, the speed is 1500m/s, 1800m/s, 2100m/s and 2400m/s in sequence, 250 shot points are arranged on the sea surface, a vertical cable is simulated in water, the position of the vertical cable in the water is 200-600m, 51 detectors are arranged on the cable in total, the recording length is 3.5s during forward operation, the sampling interval is 1ms, and the wavelet used in the forward operation process is 50Hz Rake wavelet.

After forward modeling, 250 single shot records are obtained, for example, as shown in the forward seismic record diagram of fig. 5, for a single shot record when the shot position is 125, it can be seen from the single shot record that the received signal includes up and down traveling waves, because the interference method mainly uses direct waves and multiples, which are mostly down traveling waves, and therefore, the up and down traveling wave separation of the data is required. And obtaining direct waves and multiple waves after separation.

Separating all forward seismic data, processing according to the processing flow shown in fig. 3, reconstructing the demodulator probe on the vertical cable to the sea surface shot point after the seismic interference method processing, and obtaining the virtual source seismic record of which the shot point is on the sea surface, as shown in the virtual source record chart obtained after the calculation processing of fig. 8.

In this embodiment, partial calculation noise exists in the virtual source record obtained after the seismic interference method processing, and because no noise is added in the forward modeling process, it can be determined that the interference is generated in the calculation process, and therefore, the denoising operation needs to be completed in the subsequent processing. After the obtained virtual source records, the normal work such as speed analysis, dynamic correction, superposition and the like is completed by using commercial processing software, and the superposition section of the model is obtained through processing. Fig. 9 is a time domain overlay cross-section obtained after the virtual source recording process. In the superimposed section, it can be seen that there are three strong energy in-phase axes in sequence from top to bottom, in sequence the sea bottom and two inclined interfaces. According to the relation between the velocity and the depth of each layer in the original model, the calculated two-way travel time is matched with the time on the stacking section, the accuracy of the seismic interference method in processing the vertical cable seismic exploration model is proved, and a theoretical test foundation is laid for actual data processing.

One embodiment of the present invention is to complete the processing of the actual VCS survey data based on the results of the model data processing. The practical data is collected in the southeast Qionghai area, the distance of the earthquake investigation work area is 180 kilometers from the third city, the water depth of the investigation area is about 1400-1600 meters, and the change of the submarine topography is relatively smooth. The length of the ocean vertical cable is 300 meters, the total number of the hydrophones on the cable is 12, the distance is 25 meters, the sampling rate is 2ms, and the recording length is 8 s. 58 collecting gun lines are distributed in the work area, each gun line is 1134 guns in total, and the gun spacing is 12.5 meters.

Because the actual data contains various noise interferences, the actual data is firstly subjected to preprocessing work such as denoising and the like, and then the direct wave and the multiple wave are separated. FIG. 10 is a graph of a primary raw seismic signal recorded by a geophone on a vertical cable. FIG. 11 is a diagram of direct wave signals after wave field separation, and FIG. 12 is a diagram of multiple wave signals after wave field separation.

In the actual processing process, the data of the 12 detectors on the vertical cable is processed by the seismic interference method according to the processing flow shown in fig. 3, and a virtual source record corresponding to the actual data is obtained, and fig. 13 is the virtual source record obtained by processing the actual data. And after the virtual source record obtained by processing the model data is recorded, loading the obtained data into GeoEast software to finish normal work such as speed analysis, dynamic correction, superposition and the like, and processing to obtain a superposition section of the model. FIG. 15 is a CMP104 pick-up velocity spectrum, which is a velocity spectrum of a common center gather (CMP) during velocity analysis. Fig. 16 is a velocity field diagram established after velocity analysis is recorded by a virtual source, which is a velocity field established by picking up a velocity spectrum in the velocity analysis process, in a small size CMP, the picked velocity is inaccurate because of less covering times, and as the covering times increase, the velocity gradually tends to be stable from the CMP120, and meanwhile, the change of the velocity in time is consistent with the formation change in the model. On the basis of the speed analysis, the dynamic correction work of the data is completed through the picked speed.

As can be seen from the superimposed cross-sectional view of the virtual source record after the data processing in fig. 14, the time corresponding to the direct wave is about 2000ms, the velocity of the longitudinal wave in the seawater is about 1500m/s, and through calculation, the depth of the seabed interface is about 1500m, which is about the same as the actual seawater depth of the work area, and the imaging result is more accurate. Meanwhile, in the superposed section, the stratum homophase axis is clear and changes stably, and the shallow stratum imaging effect is better and is matched with the actual condition. Therefore, in the actual data processing process, the method can obtain an accurate result, and can provide reference for subsequent accurate processing and interpretation.

An embodiment of the present invention also provides an electronic device, and as shown in fig. 17, the electronic device provided in the embodiment of the present invention is a schematic structural diagram, and the electronic device may include: a processor (processor)1701, a communication Interface (Communications Interface)1704, a memory (memory)1702, and a communication bus 1703, wherein the processor, the communication Interface, and the memory communicate with each other through the communication bus. The processor may call logic instructions in the memory to execute the underwater vertical cable seismic wave interference imaging method provided in the above embodiments, the method including: establishing a geological model, and forward modeling to obtain a common shot gather; selecting two shot point positions A and B in the plurality of shot points; arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed; obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition; completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector; calculating to obtain a common shot gather taking the position A as a virtual source; and obtaining geological imaging after calculation processing.

Furthermore, the logic instructions in the memory 1702 may be implemented in software functional units and stored in a computer readable storage medium when sold or used as a stand-alone product. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

In another aspect, an embodiment of the present invention further provides a computer program product, where the computer program product includes a computer program stored on a non-transitory computer-readable storage medium, where the computer program includes program instructions, and when the program instructions are executed by a computer, the computer is capable of executing the method for underwater vertical cable seismic wave interference imaging provided in the above embodiments, where the method includes: establishing a geological model, and forward modeling to obtain a common shot gather; selecting two shot point positions A and B in the plurality of shot points; arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed; obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition; completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector; calculating to obtain a common shot gather taking the position A as a virtual source; and obtaining geological imaging after calculation processing.

In still another aspect, an embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored, where the computer program is implemented by a processor to execute the method for underwater vertical cable seismic wave interference imaging provided in the foregoing embodiments, where the method includes: establishing a geological model, and forward modeling to obtain a common shot gather; selecting two shot point positions A and B in the plurality of shot points; arranging a plurality of detectors underwater, and performing cross-correlation operation on two shot data of a position A and a position B received by the same detector; repeatedly performing cross-correlation operation on each detector until the detector domain cycle is completed; obtaining a group of data records after interference processing, and obtaining a single-channel record with a position A simulation as a virtual source and a position B as a simulation detector after superposition; completing shot domain calculation; if the shot domain calculation is not finished, performing the step of setting a plurality of detectors on the vertical cable again and performing cross-correlation operation on two shot data of the position A and the position B received by the same detector; calculating to obtain a common shot gather taking the position A as a virtual source; and obtaining geological imaging after calculation processing.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.