Sparse excitation wideband seismic source system and data processing method

Abstract

The present invention provides a sparse excitation wideband seismic source system and a data processing method. The seismic source system includes a seismic source transmitting array and a seismic source excitation control system; the seismic source transmitting array includes a first frequency band transmitting array and a second frequency band transmitting array; the seismic source excitation control system includes: a first control end: including a first controller for generating a pseudo-random binary sequence; a second controller; a second control end: including a third controller for obtaining the transmission of the pseudo-random binary sequence and a triggering instruction for the seismic source transmitting array to generate a circular stack; a first energy storage unit and a first discharge module connected thereto; a second energy storage unit and a second discharge module connected thereto; the two discharge modules are respectively connected to the first frequency band transmitting array and the second transmitting array; the third controller generates a control signal for the first discharge module or the second discharge module. The dual-frequency excitation towed array of the present invention includes at least two frequency band seismic source transmitting arrays, and can realize wideband random excitation of the seismic source.

Description

Technical Field

[0001] The present invention relates to the technical field of marine seismic exploration, and particularly relates to a sparse excitation broadband seismic source system and a seismic source excitation and data processing method. Background Art

[0002] A marine multi-channel seismic exploration system mainly includes two parts: a seismic source and a seismic signal receiving system. Additionally, an auxiliary navigation and positioning system is required. The seismic signal receiving system includes two parts: a marine seismic streamer and a seismic data recording system. During offshore seismic operations, the transmitting array of the seismic source and the seismic streamer are towed in the seawater at the stern of the seismic survey vessel. The transmitting array of the seismic source excites seismic waves, and the seismic streamer receives seismic reflection signals.

[0003] For different types of seismic sources, the main frequencies of the excited seismic waves are different, typically ranging from dozens of hertz to thousands of hertz. Different seismic sources used in seismic operations result in different main frequencies of the excited seismic waves, leading to different formation penetration depths and resolutions. A seismic source with a main frequency of dozens of hertz has the strongest formation penetration ability and can penetrate a formation depth of up to several kilometers or even more than ten kilometers, but can only resolve formations tens of meters thick. A seismic source with a main frequency of several hundred hertz can penetrate a formation depth of about several hundred meters and can resolve formations several meters thick. A seismic source with a main frequency of thousands of hertz generally has a formation penetration depth of nearly dozens of meters, and the formation resolution ability is at the sub-meter level.

[0004] It can be seen that different seismic sources are used in different seismic operation voyages, resulting in different formation penetration depths and formation resolution abilities. To solve the contradiction between the formation penetration depth and resolution ability of the seismic exploration source, some multi-seismic-source offshore seismic operation systems have been disclosed in the prior art. For example, the Russian patent with the publication number RU2592739C discloses an offshore seismic operation method of towing three seismic sources simultaneously, and the Chinese patent with the publication number CN104049278A discloses a multi-seismic-source multi-streamer trigger timing control system and method. The multi-seismic-source system broadens the frequency range of the seismic waves excited by the seismic source. However, the methods disclosed in the prior art require towing multiple sets of seismic sources simultaneously during operations, which is difficult and risky, and it is difficult to promote and use on a large scale. Moreover, in the methods disclosed in the prior art, multiple seismic sources are sequentially excited in a predetermined order. For each individual seismic source among the multiple seismic sources, its excitation interval is inevitably enlarged, the seismic shot interval becomes larger, and the accuracy of seismic data is reduced. Summary of the Invention

[0005] The purpose of the present invention is to provide a sparse excitation broadband seismic source system and a data processing method.

[0006] To achieve the above purpose, in some embodiments of the present invention, the following technical solutions are provided:

[0007] A sparse excitation broadband seismic source system, comprising a seismic source transmitting array and a seismic source excitation control system;

[0008] The seismic source transmitting array includes: a first frequency band transmitting array and a second frequency band transmitting array;

[0009] The seismic source excitation control system includes:

[0010] The first control end: includes a first controller for generating a pseudo-random binary sequence; a second controller communicating with the first controller;

[0011] The second control end: includes a third controller communicating with the second controller to obtain the transmission of the pseudo-random binary sequence and the triggering instruction of the seismic source transmitting array; for generating a circular stack according to the pseudo-random binary sequence generated by the first controller; a first energy storage unit and a first discharge module connected thereto; a second energy storage unit and a second discharge module connected thereto; the third controller is configured to generate a control signal for the first discharge module or the second discharge module according to the current stack value of the circular stack; the output end of the first discharge module is connected to the first frequency band transmitting array, and the output end of the second discharge module is connected to the second transmitting array;

[0012] Mounting frame: The first frequency band transmitting array and the second frequency band transmitting array are both mounted on the mounting frame.

[0013] In some embodiments of the present invention, the broadband seismic source system further includes a sealed cabin, and the components of the second control end are all installed in the sealed cabin; the sealed cabin is installed on the mounting frame.

[0014] In some embodiments of the present invention, the first frequency band transmitting array includes at least one group of first seismic source bodies, and each group of first seismic source bodies includes a metal rod, the metal rod is connected to the first discharge module, and high-voltage electrodes are arranged thereon.

[0015] In some embodiments of the present invention, the second frequency band transmitting array includes at least one group of second seismic source bodies, and each group of second seismic source bodies includes an insulating housing, and a high-voltage coil, a metal plate and a flexible protective film are sequentially arranged in the housing from the first direction to the second direction; the high-voltage coil is connected to the second discharge module.

[0016] In some embodiments of the present invention, the second control end further includes:

[0017] Voltage sampling unit: connected to the first energy storage unit and the second energy storage unit, and further connected to the third controller, for collecting the power of the first energy storage unit and the second energy storage unit and feeding it back to the third controller;

[0018] Pre-charging unit, for controlling the charging of the first energy storage unit and the second energy storage unit according to the instruction of the third control.

[0019] In some embodiments of the present invention, the broadband seismic source system further includes a navigation system, and the second processor is configured to receive a seismic source trigger signal from the navigation system and generate a control signal for exciting the seismic source emission array according to the current stack value of the circular stack after receiving the trigger signal, and transmit it to the third controller.

[0020] In some embodiments of the present invention, a buoyancy component is provided on the mounting frame so that the mounting frame can float on the sea surface.

[0021] In some embodiments of the present invention, a method for seismic source system data is further provided, which uses the above-mentioned sparse excitation broadband seismic source and includes a seismic source excitation method. The seismic source excitation method includes:

[0022] The first processor generates a pseudo-random binary sequence;

[0023] The second processor sends a trigger signal for the seismic source emission array to the third processor;

[0024] The third processor generates a circular stack based on the pseudo-random binary sequence;

[0025] The third processor generates a control signal for the seismic source emission array according to the current stack value of the circular stack. If the current stack value is 0, an excitation signal for the first frequency band emission array is generated. If the current stack value is 1, an excitation signal for the second frequency band emission array is generated;

[0026] The third processor controls the activation of the corresponding seismic source emission array according to the control signal of the seismic source emission array from the second processor.

[0027] In some embodiments of the present invention, the seismic source excitation method further includes: after there is a trigger signal from the navigation system, the second processor generates a control signal for the seismic source emission array.

[0028] In some embodiments of the present invention, the data processing method further includes a seismic source seismic data reconstruction method, including:

[0029] Collect sparse excitation seismic record data of the first frequency band emission array and reconstruct it into uniform seismic record data of the first frequency band;

[0030] Collect sparse excitation seismic record data of the second frequency band emission array; and reconstruct it into uniform seismic record data of the second frequency band;

[0031] Analyze the formation imaging of different depths according to the uniform seismic record data of the first frequency band and the uniform seismic record data of the second frequency band.

[0032] Compared with the prior art, the beneficial effects of the technical solution of the present invention are as follows:

[0033] The dual-frequency excitation towed array of the present invention integrates at least two frequency band seismic source transmitting arrays. For example, it can be configured as a kHz main frequency transmitting array and a Hz main frequency transmitting array, and can achieve broadband excitation of the seismic source. Furthermore, it enables a single seismic source, a single voyage, and a single operation to obtain multiple sets of seismic data with different penetration capabilities and resolution capabilities, solves the contradiction between the formation penetration depth and resolution of the seismic exploration seismic source, improves the operation efficiency, and saves the operation cost.

[0034] The excitation mode of the seismic source of the present invention adopts random sparse excitation, and uses a pseudo-random binary sequence to control the excitation timing of different main frequency transmitting arrays of the dual sparse seismic source. This random excitation satisfies the compressive sensing theory. That is to say, two sets of seismic data with sparse excitation and irregular excitation of the seismic source can be obtained. After seismic post-processing reconstruction, two sets of seismic data with dense excitation and conventional excitation of the seismic source can be restored, and synchronous high-precision structural imaging of different depth formations can be achieved. Brief Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic diagram of the seismic operation of the sparse excitation broadband seismic source of the present invention;

[0037] Figure 2 It is a schematic diagram of the structure of the seismic source excitation control system of the present invention;

[0038] Figure 3a It is a schematic diagram of the structure of the first perspective of the transmitting array;

[0039] Figure 3b It is a schematic diagram of the structure of the second perspective of the transmitting array;

[0040] Figure 4a It is a schematic diagram of the structure of the Hz main frequency transmitting array;

[0041] Figure 4b It is a schematic diagram of the structure of the kHz main frequency transmitting array;

[0042] Figure 5 It is a schematic diagram of the structure of the dual-channel pulse energy source;

[0043] Figure 6 It is a flowchart of the operation of the sparse excitation broadband seismic source;

[0044] Figure 7 It is a schematic diagram of the shot points of the operation of the sparse excitation broadband seismic source;

[0045] In the above figures:

[0046] 1 - Survey ship; 2 - Seismic source emission array; 3 - Towed cable; 4 - Gigahertz seismic wave; 5 - Megahertz seismic wave; 6 - Shallow formation; 7 - Deep formation; 8 - Hundred - hertz main - frequency emission array; 801 - Metal rod; 802 - Insulating shell; 803 - Electrode; 9 - Kilohertz main - frequency emission array; 901 - Insulating housing; 902 - High - voltage coil; 903 - Metal plate; 904 - Flexible protective film; 10 - Sealed cabin; 11 - Mounting frame; 12 - Buoyancy component. Detailed implementation manners

[0047] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0048] It should be noted that terms such as "connection" and "communication" can refer to both direct connection and direct communication between components, and also indirect connection and indirect communication between components.

[0049] A sparse - excitation broadband seismic source system includes a seismic source emission array, a seismic source excitation control system and a towed cable.

[0050] Reference Figure 1 .

[0051] The seismic source emission array 2 is towed by the survey ship 1 and at least includes: a first - frequency - band emission array and a second - frequency - band emission array; the excitation seismic data frequencies of the two seismic source emission arrays are different, and the penetration depths into the formation are different. In this embodiment, the first - frequency - band emission array is a hundred - hertz emission array, and the second - frequency - band emission array is a kilohertz emission array. According to the operation requirements, emission arrays of other frequency bands can also be selected and configured. In addition, according to different energy requirements of the excitation seismic waves, one or more hundred - hertz main - frequency emission arrays and one or more hundred - hertz main - frequency emission arrays can be set to provide greater seismic wave energy; the kilohertz seismic wave 4 emitted by the kilohertz emission array penetrates the shallow formation 6, and the hundred - hertz seismic wave 5 emitted by the hundred - hertz emission array penetrates the deep formation 7;

[0052] Towed cable 3: Towed by the survey ship 1 and used to collect the emitted seismic waves;

[0053] Mounting rack: The first - frequency - band transmitting array and the second - frequency - band transmitting array are both mounted on the mounting rack. Different from the seismic source system in the prior art, in this embodiment, the seismic source transmitting arrays of two frequency bands are both carried on the mounting rack. In this way, during one voyage and one operation, by controlling the excitation of the seismic source transmitting arrays of two frequency bands, the sampling and analysis of seismic profile data of different - depth strata can be completed.

[0054] The seismic source excitation control system is used for the excitation control of the first - frequency - band seismic source array and the second - frequency - band seismic source array. The structure refers to Figure 2 , including:

[0055] The first control end: includes a first controller for generating a pseudo - random binary sequence; a second controller communicating with the first controller for generating a circular stack according to the pseudo - random binary sequence generated by the first controller. Specifically, the first control end can also be defined as a sparse - code generation unit. Here, the sparse code is a string of pseudo - random binary sequences, in which "0" and "1" are randomly distributed, and the number of consecutive "0"s does not exceed 3, and the number of consecutive "1"s does not exceed 3. The first controller can use a CPU, and the second controller can use an FPGA.

[0056] The second control end: includes a third controller; a first energy - storage unit and a first discharge module connected thereto; a second energy - storage unit and a second discharge module connected thereto. The third controller is configured to generate a control signal for the first discharge module or the second discharge module according to the current stack value of the circular stack. The output end of the first discharge module is connected to the first - frequency - band transmitting array, and the output end of the second discharge module is connected to the second transmitting array. Specifically, the second control end can also be defined as a dual - sparse control unit and a dual - path pulse energy source. One energy source is connected to the hundred - hertz transmitting array, and the other energy source is connected to the kilo - hertz transmitting array. Among them, the dual - sparse control unit is the third controller, which can use an MCU and communicates with the sparse - code generation unit through a communication interface to obtain control instructions and specifically control the operation of the dual - path pulse energy source, including the charging start, charging stop, and sparse excitation control of the multi - path discharge module.

[0057] The present invention integrates at least two frequency - band excitation arrays through a multi - main - frequency excitation towed array. For example, a kilo - hertz main - frequency transmitting array and a hundred - hertz main - frequency transmitting array, and thus can realize the broadband excitation of the seismic source.

[0058] In the present invention, for the dual sparse broadband seismic source, each time an external trigger signal is received, one of the two (or more) seismic sources is excited, but which specific seismic source is excited is random. This random excitation satisfies the compressive sensing theory. For a specific one of the two (or more) seismic sources, it is not excited uniformly and densely. In this way, two sets of seismic data with sparse and irregular excitation of the seismic sources can be obtained. After being reconstructed by seismic post-processing personnel, two sets of seismic data with dense and conventional excitation of the seismic sources can be restored. Since the frequency characteristics of the two sets of seismic sources are different, these two sets are seismic profiles with different resolutions and different penetration depths. In this way, during the same seismic operation voyage, seismic data with different formation penetration depths and different formation resolution capabilities can be obtained simultaneously, solving the contradiction between the formation penetration depth and the resolution capability of the seismic source in seismic exploration and improving the operation efficiency.

[0059] In some embodiments of the present invention, the structure of the seismic source emission array is as follows. Refer to Figure 4a and Figure 4b .

[0060] The first frequency band emission array, that is, the hundred-hertz main frequency emission array 8 includes at least one group of first seismic source bodies. Each group of first seismic source bodies includes a metal rod 801. The metal rod 801 is connected to the first discharge module, and high-voltage electrodes 803 are arranged thereon. An insulating protective shell 802 can be further arranged outside the metal rod, and it can be installed on the mounting rack through the insulating protective shell. The hundred-hertz main frequency emission array 8 is placed in seawater during operation. Through the instantaneous release of high voltage, the seawater around the high-voltage electrode is vaporized. The vaporized seawater generates bubbles, and the process of the bubbles expanding, compressing, and bursting generates sound waves, which propagate in the seawater.

[0061] The second frequency band emission array, that is, the kilohertz main frequency emission array 9 includes at least one group of second seismic source bodies. Each group of second seismic source bodies includes an insulating housing 901. Inside the housing, a high-voltage coil 902, a metal plate 903, and a flexible protective film 904 are sequentially arranged from the first direction to the second direction; the high-voltage coil 902 is connected to the second discharge module. The second frequency band emission array can be installed on the mounting rack 11 through the housing. The kilohertz main frequency emission array is placed in seawater during operation. Through the instantaneous release of high voltage, a strong current is generated in the high-voltage coil, and a current (eddy current) opposite to the direction of the high-voltage coil is generated in the metal plate. The electromagnetic induction force between the coil and the metal plate forces the metal plate to quickly leave the coil, driving the flexible protective film to bombard the surrounding seawater and generating sound waves in the seawater. The air contained inside the insulating protective shell plays a role similar to a spring. During the process of the metal plate leaving the coil, it limits the movement amplitude of the metal plate and pulls it back to its original position after it reaches the farthest distance.

[0062] The broadband seismic source system further includes a sealed cabin 10, which can be made of metal or carbon fiber materials, and the second control end components are all installed inside the sealed cabin; the sealed cabin is installed on the mounting rack.

[0063] A buoyancy component 12 is provided on the mounting rack 11 to provide buoyancy so that the underwater dual-frequency excitation towed array can float in seawater.

[0064] In some embodiments of the present invention, the structure of the seismic source excitation control system is as follows.

[0065] The first control end (sparse code generation unit) includes:

[0066] Trigger port: The trigger port can be connected to the integrated navigation system. In some embodiments, a navigation trigger signal can be accessed.

[0067] The first controller uses a CPU controller, including a human-machine interface and configuration software (and its general operating system, such as Windows, Linux, etc.). The human-machine interface includes a keyboard, a mouse, and a monitor. For the configuration software, the user can set the working mode and parameters of the seismic source, monitor the working status of the seismic source, and after setting and confirmation, send the user's setting commands and parameters to the second controller for storage, distribution, and execution.

[0068] Second controller: Communicates with the trigger port, and the navigation trigger signal will be transmitted to the second controller.

[0069] In addition, the second controller is also connected to a timing module, a memory, and a power supply control module.

[0070] The timing and positioning module is used to receive the 1pps timing signal and NMEA information of positioning satellites (such as GPS, Beidou, etc.) as the clock reference of the sparse code generation unit. When working, the timing and positioning module needs to be used in cooperation with an outdoor satellite antenna. The clock accuracy of the sparse code generation unit integrated with the timing and positioning module can reach the microsecond level, meeting the timing requirements for seismic source excitation in seismic operations.

[0071] The upper power supply control module performs AC / DC conversion on the AC mains (220VAC power supply or 380VAC power supply). One path (high-voltage DC power supply) is transmitted downward through the upper I / O interface for use by the pulse energy source and the dual-sparse control unit, and the other path (low-voltage DC power supply) is for use by the sparse code generation unit.

[0072] The memory is used to store the operating system, configuration software, user setting files, and seismic source excitation shot time files. Preferably, the memory is a hard disk (including a hard disk management module) or an SD card (including an SD card management module).

[0073] The second control end includes a dual-sparse control unit and a dual-channel pulse energy source.

[0074] The dual-channel pulse energy source includes a pre-charging module, an IGBT conversion circuit, a boost rectification module, a multi-channel energy storage capacitor bank, and a multi-channel discharge module. The circuit schematic diagram of the dual-channel pulse energy source is as Figure 5 shown.

[0075] The pre-charging module pre-stores part of the electric energy before and after the multi-channel energy storage capacitor bank is charged, which can effectively reduce the instantaneous demand for power supply during the charging of the multi-channel energy storage capacitor bank, reduce the impact current interference, and reduce the power loss.

[0076] The IGBT conversion circuit converts direct current into high-frequency alternating current. The higher-frequency alternating current can effectively reduce the volume and weight of the boost rectification module. At the same time, the IGBT conversion circuit is controlled by the IGBT control circuit in the dual sparse control unit. The dual sparse control unit can start and stop the operation of the IGBT conversion circuit according to the voltage of the multi-channel energy storage capacitor bank, and then start and stop charging the multi-channel energy storage capacitor bank.

[0077] The boost rectification module boosts the high-frequency alternating current, and after boosting, AC / DC is converted into high-voltage direct current (up to 5600V).

[0078] The multi-channel energy storage capacitor bank includes at least two energy storage capacitor banks. Each energy storage capacitor bank includes one or more high-voltage pulse capacitors connected in parallel. The output of each energy storage capacitor bank is correspondingly connected to a set of seismic source emission arrays. There are isolation diodes at both ends of each energy storage capacitor bank to avoid inter-channel interference between the multi-channel energy storage capacitor banks during charging and discharging.

[0079] The multi-channel discharge module includes at least two discharge modules. Each discharge module includes a set of solid-state switches and freewheeling diodes. The input end of each discharge module is correspondingly connected to an energy storage capacitor bank, and the output end is correspondingly connected to a set of seismic source emission arrays. The driving signal of the corresponding seismic source array can be controlled by controlling the on-off of the solid-state switches on the multi-channel discharge module. After the switch is turned on, the electric energy of this energy storage capacitor bank is output to the emission array of this path, thereby exciting sound waves.

[0080] In the multi-channel discharge module, since the solid-state switches of each discharge circuit are not turned on synchronously, there will be differences in the voltage drops of the energy storage capacitors. The isolation diodes at both ends of the energy storage capacitors play an isolation role. On the one hand, it avoids the phenomenon of high-voltage capacitor banks charging low-voltage capacitor banks, and on the other hand, it avoids the problem that the current rises too fast and breaks down the solid-state switch due to the superposition of multi-channel currents in a certain path during discharge.

[0081] The dual sparse control unit includes a microcontroller unit MCU, an IGBT control circuit, a multi-channel voltage sampling unit, a multi-channel switch control module, a lower-level power supply control, and a lower-level I / O interface.

[0082] The lower I / O interface is used for communication and power connection with the sparse code generation unit. It transmits the DC power supply of the sparse code generation unit to the dual sparse control unit, transmits the commands sent by the sparse code generation unit to the dual sparse control unit, and transmits the status information of the dual sparse control unit to the sparse code generation unit.

[0083] Lower power control: It transforms the DC power supply transmitted from the sparse code generation unit to the dual sparse control unit. One way is directly sent to the pre-charging module of the pulse energy source, and the other way is DC / DC buck-converted for the dual sparse control unit to use.

[0084] The third controller, namely the microcontroller unit MCU, receives the commands from the sparse code generation unit, including the excitation energy and working mode, and serves as the core of the dual sparse control unit to control the operation of each module.

[0085] The IGBT control circuit controls the operation of the IGBT frequency conversion module of the pulse energy source according to the instructions of the MCU, including start, stop, etc., and further controls the start and end of charging of the energy storage capacitor bank. The MCU starts to command the IGBT control circuit to start charging the energy storage capacitor bank after each excitation, and monitors the voltage of the energy storage capacitor bank in real time. After reaching the established voltage, it commands the IGBT control circuit to stop charging the energy storage capacitor bank.

[0086] The multi-channel voltage sampling unit: It is connected to the first energy storage unit and the second energy storage unit, and further connected to the third controller, and is used to collect the power of the first energy storage unit and the second energy storage unit and feedback it to the third controller;

[0087] The multi-channel switch control module turns on the solid-state switches of each path according to the instructions of the MCU. After the solid-state switches are opened, the energy storage capacitor bank of this path is connected to the transmitting array, and the electric energy stored in the energy storage capacitor bank is instantly discharged through the transmitting array to excite seismic waves.

[0088] In some embodiments of the present invention, a seismic source system data method is further provided. Using the above-mentioned sparse excitation wide-frequency seismic source, it includes a seismic source excitation method, and the seismic source excitation method includes:

[0089] The first processor generates a pseudo-random binary sequence;

[0090] The second processor forwards the pseudo-random binary sequence and simultaneously issues a seismic source excitation array trigger signal to the third processor. In some embodiments, the second processor receives the trigger signal sent by the integrated navigation system and sends it to the third processor as the seismic source excitation array trigger signal;

[0091] The third processor generates a circular stack based on a pseudo-random binary sequence, and generates a control signal for the seismic source emission array according to the current stack value of the circular stack. If the current stack value is 0, it generates an excitation signal for the first frequency band emission array. If the current stack value is 1, it generates an excitation signal for the second frequency band emission array. Specifically, "0" and "1" in the pseudo-random binary sequence are used as the control codes for the dual-channel discharge module.

[0092] The third processor controls the activation of the corresponding seismic source emission array according to the control signal of the seismic source emission array from the second processor.

[0093] Furthermore, as an improvement of the present invention, in some embodiments, if the seismic source emission array includes emission arrays of four frequency bands, two bits in the pseudo-random binary sequence can also be used as the control codes for the multi-channel discharge module, that is, "00", "01", "10", "11" are used as the control codes for the four-channel discharge module to control the activation of the four emission arrays.

[0094] In some embodiments of the present invention, the seismic source excitation method further includes: after there is a trigger signal from the navigation system, the second processor generates a control signal for the seismic source emission array.

[0095] In some embodiments of the present invention, the data processing method further includes a seismic source seismic data reconstruction method, including:

[0096] Collecting sparse excitation seismic record data of the first frequency band emission array and reconstructing it into uniformly sampled seismic record data of the first frequency band;

[0097] Collecting sparse excitation seismic record data of the second frequency band emission array and reconstructing it into uniformly sampled seismic record data of the second frequency band;

[0098] Analyzing the formation imaging of different depths according to the uniformly sampled seismic record data of the first frequency band and the uniformly sampled seismic record data of the second frequency band.

[0099] The complete working process flow diagram of the method of the present invention is as follows:

[0100] (1) The user configures parameter instructions such as excitation energy through the sparse code generation unit configuration software.

[0101] (2) The user generates a pseudo-random binary sequence S based on the compressed sensing theory through the sparse code generation unit CPU configuration software.

[0102] (3) The CPU sends the parameter instructions and the sequence S to the FPGA.

[0103] (4) The FPGA forwards the excitation energy parameter instructions and the sequence s to the dual sparse control unit, and is also responsible for receiving the trigger signal sent by the integrated navigation system.

[0104] (5) The dual sparse control unit MCU stores the user settings, generates a circular stack, and controls the charging of the pulsed energy source to the specified energy.

[0105] (6) Wait to receive the external trigger signal provided by the integrated navigation system.

[0106] (7) The MCU determines which seismic source to trigger based on the stack value pointed to by the current pointer.

[0107] (8) If the current stack value is 0, the hundred-hertz main frequency emission array is triggered after receiving the external trigger signal; if the current stack value is 1, the kilohertz main frequency emission array is triggered after receiving the external trigger signal. (The positions of the shot points are as Figure 7 shown)

[0108] (9) Add 1 record to the shot time file and increment the circular stack pointer by 1

[0109] (10) Return to step 5 and execute in a loop.

[0110] (11) The process described in the previous steps is the excitation process of the seismic source. During the seismic operation, the seismic streamer receives seismic wave signals.

[0111] (12) The acquisition system records and stores the seismic data received by the seismic streamer.

[0112] (13) According to the shot time file, the post-processing personnel decompose the seismic data into two sets of seismic records with sparse excitation: one set is the seismic record with sparse excitation by the kilohertz main frequency emission array, and the other set is the seismic record with sparse excitation by the hundred-hertz main frequency emission array.

[0113] (14) The post-processing personnel respectively reconstruct the two sets of seismic records with sparse excitation into a kilohertz main frequency seismic record (the positions of the shot points are as Figure 7 shown) and a hundred-hertz main frequency seismic record (the positions of the shot points are as Figure 7 shown). These two sets are seismic profiles with different resolutions and different penetration depths. There are mainly three types of reconstruction algorithms: convex optimization algorithms, greedy algorithms, and combinatorial algorithms.

[0114] (15) The post-processing personnel process, interpret the seismic record data excited by the two different seismic sources, and image the formation structure.

[0115] In addition to the random dual-source mode working mode, the seismic source system also has a coded seismic source working mode. In the coded seismic source working mode, the two seismic sources are sequentially triggered according to the set order and coding time. This mode can effectively improve the detection depth and resolution of small-energy seismic sources and has strong anti-interference ability.

[0116] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A sparse excitation wideband seismic source system, characterized in that, It includes a seismic source emission array and a seismic source excitation control system; The seismic source emission array includes: a first frequency band emission array and a second frequency band emission array; The seismic source excitation control system includes: The first control end: includes a first controller for generating a pseudo-random binary sequence; a second controller communicating with the first controller for generating a circular stack according to the pseudo-random binary sequence generated by the first controller; The second control end: includes a third controller communicating with the second controller to obtain a seismic source emission array trigger instruction; a first energy storage unit and a first discharge module connected thereto; a second energy storage unit and a second discharge module connected thereto; the third controller is configured to generate a control signal for the first discharge module or the second discharge module according to the current stack value of the circular stack; the output end of the first discharge module is connected to the first frequency band emission array, and the output end of the second discharge module is connected to the second emission array; Mounting frame: The first frequency band emission array and the second frequency band emission array are both mounted on the mounting frame; Among them, a control signal for the seismic source emission array is generated according to the current stack value of the circular stack. If the current stack value is 0, an excitation signal for the first frequency band emission array is generated. If the current stack value is 1, an excitation signal for the second frequency band emission array is generated; in the pseudo-random binary sequence, "0" and "1" are randomly distributed, and the number of consecutive "0"s does not exceed 3, and the number of consecutive "1"s does not exceed 3.

2. The sparse excitation wideband seismic source system according to claim 1, characterized in that, The sparse excitation wideband seismic source system further includes a sealed cabin, and the components of the second control end are all installed in the sealed cabin; the sealed cabin is installed on the mounting frame.

3. The sparse excitation wideband seismic source system according to claim 1, wherein The first frequency band emission array includes at least one group of first seismic source bodies, and each group of first seismic source bodies includes a metal rod, the metal rod is connected to the first discharge module, and high-voltage electrodes are arranged thereon.

4. The sparse excitation broadband seismic source system according to claim 1, characterized in that, The second frequency band emission array includes at least one group of second seismic source bodies, and each group of second seismic source bodies includes an insulating housing, and a high-voltage coil, a metal plate and a flexible protective film are sequentially arranged in the insulating housing from the first direction to the second direction; the high-voltage coil is connected to the second discharge module.

5. The sparse excitation wideband seismic source system according to claim 1, wherein, The second control end further includes: A voltage sampling unit: connected to the first energy storage unit and the second energy storage unit, and further connected to the third controller, for collecting the power of the first energy storage unit and the second energy storage unit and feeding it back to the third controller; A pre-charging unit for controlling the charging of the first energy storage unit and the second energy storage unit according to the instruction of the third controller.

6. The sparse excitation broadband seismic source system according to claim 1, characterized in that The second processor of the sparse excitation wideband seismic source system is configured to receive the seismic source trigger signal of the integrated navigation system and transmit it to the third controller.

7. The sparse excitation wideband seismic source system according to claim 1, characterized in that A buoyancy component is arranged on the mounting frame so that the mounting frame can float on the sea surface.

8. A method for processing data of a seismic source system, using the sparse excitation wideband seismic source system described in any one of claims 1 to 7, characterized in that, It includes a seismic source excitation method, and the seismic source excitation method includes: The first processor generates a pseudo-random binary sequence; The second processor issues a seismic source emission array trigger signal to the third processor; The third processor generates a circular stack based on the pseudo-random binary sequence; The third processor generates a control signal for the seismic source emission array according to the current stack value of the circular stack. If the current stack value is 0, it generates an excitation signal for the first frequency band emission array. If the current stack value is 1, it generates an excitation signal for the second frequency band emission array. In the pseudo-random binary sequence, the "0"s and "1"s are randomly distributed, and the number of consecutive "0"s does not exceed 3, and the number of consecutive "1"s does not exceed 3. The third processor controls the activation of the corresponding seismic source emission array according to the control signal of the seismic source emission array of the second processor.

9. The method for processing seismic source system data according to claim 8, characterized in that, The seismic source excitation method further includes: after there is a trigger signal from the navigation system, the second processor generates a control signal for the seismic source emission array.

10. The method for processing seismic source system data according to claim 8, characterized in that, The data processing method further includes a seismic source seismic data reconstruction method, including: Collecting sparse excitation seismic recording data of the first frequency band emission array and reconstructing it into uniformly sampled seismic recording data of the first frequency band; Collecting sparse excitation seismic recording data of the second frequency band emission array and reconstructing it into uniformly sampled seismic recording data of the second frequency band; Analyzing the formation structure imaging at different depths based on the uniformly sampled seismic recording data of the first frequency band and the uniformly sampled seismic recording data of the second frequency band.

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