Seismic data acquisition system

Abstract

The invention discloses a seismic data acquisition system, and relates to the technical field of seismic exploration, and the system comprises a power device, at least two towing cables, and at least two towing cable expanders. The towing rope expanders are respectively connected with one ends of the towing ropes, and the other ends of the towing ropes are connected to the power device; the ends of the towing cable are connected through a transverse bridging cable, and the two ends on the outermost side are further connected with the towing cable expander through reins respectively. The towrope comprises a forwarding node, a plurality of working sections, a plurality of acquisition nodes and a plurality of connection sections. The forwarding node is connected with one working section, the working sections are connected through the connecting sections, and the collecting nodes are arranged in the working sections respectively; the forwarding node is used as an end; one of the forwarding nodes connected with the towing cable expander is used as a lumped node; and the lumped node establishes communication connection with a recording system on the power device. The collection efficiency can be improved and the collection capability can be expanded through the plurality of towropes, and the collection system is simple in structure and low in production cost.

Description

Technical Field

[0001] The present application relates to the technical field of data acquisition systems, and in particular to a seismic data acquisition system. Background Art

[0002] Conventional marine 3D seismic data acquisition is very expensive. Most researchers use seismic data collected by industry or a few multi-cable research vessels to conduct relevant geological and geophysical research, which makes it difficult to carry out practical applications in academic research. More than 70% of the cost of marine seismic exploration is concentrated in the acquisition operation link. The high data acquisition cost limits geological exploration and research. Summary of the invention

[0003] The main purpose of the embodiments of the present application is to provide a seismic data acquisition system to reduce the cost of seismic data acquisition and improve the ability to acquire seismic data.

[0004] To achieve the above-mentioned purpose, one aspect of an embodiment of the present application provides a seismic data acquisition system, the seismic data acquisition system comprising: a power device, at least two streamers, and at least two streamer extenders;

[0005] Wherein, each of the towline extenders is connected to one end of a towline, and the other end of each towline is connected to the power device;

[0006] The ends of the tow cables are connected by transverse jumper cables, and the two outermost ends are also connected to a tow cable expander by a rein respectively;

[0007] Each of the streamers includes a forwarding node, a plurality of working sections, a plurality of collecting nodes and a plurality of connecting sections; wherein the forwarding node is connected to one of the working sections, the working sections are connected via the connecting sections, and the collecting nodes are respectively arranged in the working sections; the forwarding node serves as the end; one of the forwarding nodes connected to the streamer extender serves as a lumped node; the lumped node establishes a communication connection with the recording system on the power device;

[0008] The power device is used to drive each of the towline extenders to move through the towline, so as to drive each of the towlines to move;

[0009] The acquisition node is used to acquire seismic data;

[0010] The forwarding node is used to forward the seismic data collected by each of the collection nodes on the streamer to the lumping node;

[0011] The lumped node is used to transmit the seismic data collected by each of the collection nodes on each of the streamers to the recording system.

[0012] In some embodiments, a plurality of hydrophones are disposed in the working section;

[0013] The acquisition node includes an acquisition module, a transmission module and a first power supply module;

[0014] Wherein, the acquisition module is used to acquire data acquired by each of the hydrophones in the working sections on both sides of the acquisition node as the seismic data;

[0015] The transmission module is used to transmit the seismic data collected by the acquisition module at this level and / or the acquisition module at a lower level to the transmission module at an upper level or the forwarding node;

[0016] The first power supply module is used for supplying power.

[0017] In some embodiments, the acquisition module includes: a first control unit, a synchronization control circuit, a state monitoring circuit, a plurality of analog-to-digital conversion circuits, and a digital-to-analog conversion circuit;

[0018] Wherein, the first end of each of the analog-to-digital conversion circuits is connected to one of the hydrophones, the second end of each of the analog-to-digital conversion circuits is connected to the digital-to-analog conversion circuit, the third end of each of the analog-to-digital conversion circuits is connected to the synchronization control circuit, and the fourth end of each of the analog-to-digital conversion circuits is connected to the first control unit;

[0019] The synchronization control unit is also connected to the first control unit, and the first control unit is also connected to the state monitoring circuit and the transmission module respectively.

[0020] In some embodiments, the transmission module includes: a second control unit, a first driver chip, a second driver chip, a first equalizer chip, a second equalizer chip, a first isolation transformer, a second isolation transformer, a clock data recovery chip, a reset circuit, a crystal oscillator circuit, a JTAG download circuit, and a power supply circuit;

[0021] Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, the second driving chip, the clock data recovery chip, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module;

[0022] The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node;

[0023] The second driving chip is also connected to the second isolation transformer, the second equalizing chip is respectively connected to the clock data recovery chip and the second isolation transformer, and the second isolation transformer is also connected to the upper transmission module.

[0024] In some embodiments, the forwarding node includes a forwarding module and a second power module;

[0025] The forwarding module is used to forward the seismic data collected by each collection node of the current streamer and / or the previous streamer to the forwarding module of the next streamer or the lumping node;

[0026] The second power supply module is used for supplying power.

[0027] In some embodiments, the forwarding module includes: a second control unit, a first driver chip, two second driver chips, a first balancing chip, two second balancing chips, a first isolation transformer, two second isolation transformers, two clock data recovery chips, a reset circuit, a crystal oscillator circuit, a JTAG download circuit, and a power supply circuit;

[0028] Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, two of the second driving chips, two of the clock data recovery chips, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module;

[0029] The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node;

[0030] The two second driving chips are respectively connected to one second isolation transformer, the two second balancing chips are respectively connected to one clock data recovery chip and one second isolation transformer, and the two second isolation transformers are respectively connected to the corresponding upper transmission module.

[0031] In some embodiments, the lumped node is connected to the recording system on the power device via an optical fiber;

[0032] The centralized node includes the forwarding node and a first optoelectronic transceiver module.

[0033] In some embodiments, the recording system includes: a host computer, a data transmission interface, a third control unit, an equalizer, a driver, a second optoelectronic transceiver module, and a third isolation transformer;

[0034] Wherein, one end of the data transmission interface is connected to the host computer, and the other end of the data transmission interface is connected to the third unit;

[0035] The third control unit is also connected to the equalizer, the driver, the GPS system, the NTP server and the source system respectively;

[0036] One end of the third isolation transformer and the second optoelectronic transceiver module is connected to the lumped node,

[0037] The other end of the third isolation transformer is connected to the equalizer, and the other end of the second optoelectronic transceiver module is connected to the driver.

[0038] In some embodiments, the forwarding node and the aggregation node are further used to receive and / or forward commands issued by the recording system.

[0039] In some embodiments, the streamer further comprises an elastic section;

[0040] The forwarding node in the streamer is connected to one of the working segments via the elastic segment; wherein one end of the elastic segment is connected to the forwarding node, and the other end of the elastic segment is connected to one of the working segments.

[0041] In some embodiments, the seismic data acquisition system further comprises a float;

[0042] One end of the floating body is connected to the power device, and the other end of the floating body is connected to each of the towing cables.

[0043] The embodiments of the present application include at least the following beneficial effects:

[0044] The seismic data acquisition system of the present application includes a power device, at least two tow cables, and at least two tow cable extenders; wherein each tow cable extender is respectively connected to one end of a tow rope, and the other end of each tow rope is connected to the power device; the ends of each tow cable are connected by a transverse jumper cable, wherein the two outermost ends are also respectively connected to a tow cable extender by a rein; each tow cable includes a forwarding node, multiple working sections, multiple acquisition nodes and several connecting sections; wherein the forwarding node is connected to a working section, each working section is connected by a connecting section, and each acquisition node is respectively arranged in each working section; the forwarding node serves as an end; one of the forwarding nodes connected to the tow cable extender serves as a lumped node; the lumped node establishes a communication connection with the recording system on the power device; the power device is used to drive each tow cable extender to move through the tow rope to drive each tow cable to move; the acquisition node is used to collect seismic data; the forwarding node is used to forward the seismic data collected by each acquisition node on the tow cable to the lumped node; the lumped node is used to transmit the seismic data collected by each acquisition node on each tow cable to the recording system. The present application can realize the collection of seismic data through multiple tow cables, which can greatly improve the collection efficiency and effectively expand the number of tow cables and the collection capacity. In addition, the collection system of the present application has a simple structure and a low production cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0046] Figure 1 An exemplary structural diagram of a seismic data acquisition system provided in an embodiment of the present application;

[0047] Figure 2 An exemplary structural diagram of another seismic data acquisition system provided in an embodiment of the present application;

[0048] Figure 3 An example structural diagram of a collection module provided in an embodiment of the present application;

[0049] Figure 4 An exemplary structural diagram of a transmission module provided in an embodiment of the present application;

[0050] Figure 5 The workflow diagram of the acquisition module provided in the embodiment of the present application;

[0051] Figure 6 An exemplary structural diagram of a forwarding module provided in an embodiment of the present application;

[0052] Figure 7 An exemplary structural diagram of another forwarding module provided in an embodiment of the present application;

[0053] Figure 8 An exemplary structural diagram of a lumped module provided in an embodiment of the present application;

[0054] Fig. 9 An exemplary structural diagram of another lumped module provided in an embodiment of the present application;

[0055] Fig.10 An example structural diagram of a recording system provided in an embodiment of the present application;

[0056] Fig.11 This is an example diagram of the communication structure of the acquisition system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below in conjunction with the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the present application and are not intended to limit the present application. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the embodiments of the present application. They are only examples of devices and methods consistent with some aspects of the embodiments of the present application as detailed in the attached claims.

[0058] It is understood that the terms "first", "second", etc. used in this application can be used to describe various concepts in this article, but unless otherwise specified, these concepts are not limited by these terms. These terms are only used to distinguish one concept from another concept. For example, without departing from the scope of the embodiment of the present application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Depending on the context, the words "if" and "if" as used herein can be interpreted as "at the time of" or "when" or "in response to determination".

[0059] The terms "at least one", "multiple", "each", "any", etc. used in this application, at least one includes one, two or more, multiple includes two or more, each refers to each of the corresponding multiple, and any refers to any one of the multiple.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0061] Before describing the embodiments of the present application in detail, some related technologies involved in the embodiments of the present application are first described as follows:

[0062] Marine 3D seismic data acquisition is usually completed by a ship towing a seismic source and multiple seismic streamers (buoyant cables equipped with hydrophones). Each streamer is connected by a leader section and towed by a corresponding cable winch. During the seismic data acquisition process, the ship travels in the waters above the seabed target according to a predetermined route, dragging the streamer in the direction of the survey line while exciting seismic waves through the seismic source, and the hydrophones placed in the floater in a specific arrangement record the signals transmitted from the seismic waves downward to the underground reflective layer and returned.

[0063] Due to the development of information and computer technology, the oil industry has begun to frequently use 3D marine reflection seismic acquisition and imaging technology. Although the imaging results of 3D marine reflection seismic can accurately identify the spatial changes of underground complex bodies, the cost of marine 3D seismic data acquisition and processing is very expensive, which makes it difficult to carry out practical related applications in academic research. Most researchers use seismic data collected by the industry or the world's few multi-cable research vessels to carry out related geological and geophysical research. Therefore, a low-cost single-leader towing multi-cable operation technology solution is urgently needed.

[0064] In view of the shortcomings of conventional 3D seismic acquisition in the fine exploration of natural gas hydrates, the embodiments of the present application can adopt a "single leader segment-multiple working segments" right-angle comb-shaped topology structure, breaking through the conventional 3D seismic data acquisition and transmission and underwater equipment expansion towing mode. The data collected by multiple seismic cables are combined and transmitted back through the underwater aggregation module, completely getting rid of the limitations of the number of ship-borne winches and leader segments on the cable capacity. Combined with the technical solution for towing and releasing small 3D seismic underwater equipment, three winches and one leader segment can realize the acquisition operation of more than twelve seismic cables, greatly reducing the requirements and production costs of 3D seismic ships and equipment, and effectively expanding the number of cables and investigation capabilities of existing 3D ships.

[0065] Next, a seismic data acquisition system provided in an embodiment of the present application is described. The seismic data acquisition system includes: a power device, at least two streamers, and at least two streamer expanders;

[0066] Wherein, each of the towline extenders is connected to one end of a towline, and the other end of each towline is connected to the power device;

[0067] The ends of the tow cables are connected by transverse jumper cables, and the two outermost ends are also connected to a tow cable expander by a rein respectively;

[0068] Each of the streamers includes a forwarding node, a plurality of working sections, a plurality of collecting nodes and a plurality of connecting sections; wherein the forwarding node is connected to one of the working sections, the working sections are connected via the connecting sections, and the collecting nodes are respectively arranged in the working sections; the forwarding node serves as the end; one of the forwarding nodes connected to the streamer extender serves as a lumped node; the lumped node establishes a communication connection with the recording system on the power device;

[0069] The power device is used to drive each of the towline extenders to move through the towline, so as to drive each of the towlines to move;

[0070] The acquisition node is used to acquire seismic data;

[0071] The forwarding node is used to forward the seismic data collected by each of the collection nodes on the streamer to the lumping node;

[0072] The lumped node is used to transmit the seismic data collected by each of the collection nodes on each of the streamers to the recording system.

[0073] It can be understood that the communication connection mode between the aggregate node and the recording system of this embodiment includes wired connection and wireless connection. When a wired connection mode is adopted, a communication cable can be used for connection, and the communication cable serves as a leading segment.

[0074] Exemplarily, the acquisition system of this embodiment may adopt a "single leading segment - multiple working segments" right-angle comb topology structure. Figure 1 This is an example structure diagram of the acquisition system of this embodiment, in which the seismic drill can be used as a power device. This embodiment adopts a low-speed-high-speed hybrid pipeline data transmission model, breaking through the conventional three-dimensional seismic data acquisition and transmission and underwater equipment expansion towing mode. The data collected by multiple seismic cables (i.e., tow cables) are transmitted back through the underwater aggregation module in one path. The data is transmitted from the lower node transmission module to the upper node transmission module in the working section acquisition node in a low-speed single-stage manner, and is transmitted to the forwarding node aggregation module in the cross-section forwarding node in a high-speed double-stage manner, and uploaded to the recording system through a single leading segment. The working section acquisition node only sends the seismic data of one acquisition node at a time, so the working section adopts a lower transmission rate; the cross-section forwarding node sends the data of the entire working section at a time, so the cross-section adopts a higher transmission rate. Finally, the aggregation module sends the data of all acquisition nodes of the exploration system to the recording system through the leading segment.

[0075] Furthermore, a plurality of hydrophones are arranged in the working section;

[0076] The acquisition node includes an acquisition module, a transmission module and a first power supply module;

[0077] Wherein, the acquisition module is used to acquire data acquired by each of the hydrophones in the working sections on both sides of the acquisition node as the seismic data;

[0078] The transmission module is used to transmit the seismic data collected by the acquisition module at this level and / or the acquisition module at a lower level to the transmission module at an upper level or the forwarding node;

[0079] The first power supply module is used for supplying power.

[0080] As another further implementation, the forwarding node includes a forwarding module and a second power supply module;

[0081] The forwarding module is used to forward the seismic data collected by each collection node of the current streamer and / or the previous streamer to the forwarding module of the next streamer or the lumping node;

[0082] The second power supply module is used for supplying power.

[0083] Optionally, the seismic data acquisition system further comprises a floating body;

[0084] One end of the floating body is connected to the power device, and the other end of the floating body is connected to each of the towing cables.

[0085] Reference Figure 2 In an optional embodiment, the "single leading segment-multiple working segments" right-angle comb-shaped topology of this embodiment may include: 1 leading segment and 4 working segments, the length of the leading segment is 400m, and the leading segment includes optical fiber, power line and transmission line. There is 1 forwarding node and 2 collection nodes and multi-channel hydrophone on each working segment, and there is a jumper segment between the forwarding nodes. The forwarding node includes a forwarding module and a power module, and the collection node includes a collection module, a transmission module and a power module. The spacing of the hydrophone channels is 3.125m, and the working segment is divided into 4 small segments, each of which is 37.5 meters long. The length of a single working segment is 150 meters, and there are power lines, transmission lines and hydrophone signal lines inside the working segment. There is a jumper segment between the forwarding nodes, and there is no hydrophone channel inside, only power lines and transmission lines, and the length of the jumper segment is 50m.

[0086] In some embodiments, the forwarding node and the aggregation node are further used to receive and / or forward commands issued by the recording system.

[0087] The acquisition module of the acquisition node receives the analog signals of the 12 hydrophone channels on the left and right sides of the acquisition node, converts the 24 analog signals into digital signals and sends them to the transmission module of the acquisition node. The function of the transmission module of the acquisition node is similar to that of the forwarding module of the forwarding node. It receives the synchronization information and command information transmitted by the forwarding node or the acquisition node of the current working segment, and sends the local acquisition data and the data information uploaded by the lower-level acquisition node at the same time.

[0088] The functions of the forwarding module of the forwarding node are as follows: receiving the synchronization information and command information transmitted from the upper-level forwarding node, forwarding it to the lower-level forwarding node on the one hand, and forwarding it to the collection node of the working segment at this level on the other hand; receiving the data information uploaded by the collection node of the working segment at this level and the data information uploaded by the lower-level forwarding node, and uploading this data information to the upper-level forwarding node.

[0089] Functions of the forwarding node lumped module: The lumped module and the forwarding module differ in interface. Since the lumped module needs to be connected to the leading segment for long-distance high-speed data transmission, the data between the lumped module and the recording system is transmitted via optical fiber. The lumped module is equipped with an optoelectronic transceiver module, which can convert electrical signals into optical signals and send them to the recording system via optical fiber. The other parts have the same functions as the forwarding module of the forwarding node.

[0090] More specifically, the acquisition module includes: a first control unit, a synchronization control circuit, a state monitoring circuit, a plurality of analog-to-digital conversion circuits, and a digital-to-analog conversion circuit;

[0091] Wherein, the first end of each of the analog-to-digital conversion circuits is connected to one of the hydrophones, the second end of each of the analog-to-digital conversion circuits is connected to the digital-to-analog conversion circuit, the third end of each of the analog-to-digital conversion circuits is connected to the synchronization control circuit, and the fourth end of each of the analog-to-digital conversion circuits is connected to the first control unit;

[0092] The synchronization control unit is also connected to the first control unit, and the first control unit is also connected to the state monitoring circuit and the transmission module respectively.

[0093] For example, refer to Figure 3 , this embodiment provides an example structural diagram of a collection module.

[0094] The acquisition module of the acquisition node first conditions the 24-channel signal. The conditioned signal is converted by the ADC (analog-to-digital conversion circuit) and the converted digital signal is input into the FPGA (control unit) for transmission to the transmission module. At the same time, a self-test module is set on the acquisition module to check the acquisition parameters of the system. The FPGA of the acquisition module receives the command signal sent by the transmission module and analyzes it, and performs data acquisition or system self-test according to the command signal.

[0095] When the system performs data acquisition, the FPGA sends a command to configure the ADC to collect the hydrophone signal and perform signal conditioning. The conditioned hydroacoustic signal is converted from analog to digital through the ADC and sent to the FPGA for transmission to the transmission module. When the system performs a self-test, the FPGA controls the analog switch to switch to the DAC (digital-to-analog conversion circuit) self-test test signal, and generates a corresponding test signal according to the command. After the test signal is conditioned, it is converted from analog to digital through the ADC and sent to the FPGA for transmission to the transmission module.

[0096] As another more specific implementation, the transmission module includes: a second control unit, a first driver chip, a second driver chip, a first equalizer chip, a second equalizer chip, a first isolation transformer, a second isolation transformer, a clock data recovery chip, a reset circuit, a crystal oscillator circuit, a JTAG download circuit and a power supply circuit;

[0097] Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, the second driving chip, the clock data recovery chip, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module;

[0098] The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node;

[0099] The second driving chip is also connected to the second isolation transformer, the second equalizing chip is respectively connected to the clock data recovery chip and the second isolation transformer, and the second isolation transformer is also connected to the upper transmission module.

[0100] For example, Figure 4The following is an example structure diagram of the acquisition node transmission module. The hardware of the acquisition node transmission module consists of FPGA, FPGA peripheral circuit, driver chip, equalizer chip, isolation transformer, clock data recovery chip and power supply. Among them, FPGA controls the entire data transmission process of the acquisition node transmission module, including the reception, identification and issuance of downlink command information, the reception and issuance of downlink synchronization information, the reception and upload of local data, and the reception and upload of data of the lower-level acquisition node. The FPGA peripheral circuit includes a crystal oscillator, a reset circuit and a JTAG download circuit. The crystal oscillator provides the working clock for the FPGA, the reset circuit restores the initial state of the circuit, and the JTAG download circuit completes the program burning and debugging. The equalizer chip receives data. After the data is transmitted over a long distance, the signal will be attenuated. The equalizer chip balances and shapes the data to restore the data to the state when it was sent. The driver chip sends data, drives the transmission signal, and adjusts the voltage of the output signal at the sending end to reduce the attenuation of the signal. The isolation transformer can not only enhance the signal and reduce the signal attenuation, but also isolate the external electromagnetic interference signal and high voltage, and improve the anti-interference and anti-risk capabilities of the circuit board. The clock data recovery chip recovers the clock signal from the serial data and provides the working clock for data processing inside the FPGA. The power supply provides power for all the above circuits, including 5V, 3.3V, 2.5V and 1.2V.

[0101] The commands and synchronization information sent by the forwarding node first pass through the isolation transformer of the transmission module of the acquisition node, and then are input into the FPGA after the signal is shaped by the equalizing chip. On the one hand, the FPGA receives and parses the command, and on the other hand, it forwards the command and synchronization information, and sends it to the lower-level acquisition node after passing through the driver chip and isolation transformer. The data of the lower-level acquisition node also enters the clock data recovery chip after passing through the isolation transformer and the equalizing chip, recovers the clock from the data, and inputs the recovered clock and recovered data into the FPGA. The FPGA receives and frames the data for transmission, and uploads it to the upper-level node after passing through the driver chip and isolation transformer. The acquisition module of the local acquisition node directly sends the data to the FPGA, which receives and frames the data for transmission, and uploads it to the upper-level node after passing through the driver chip and isolation transformer.

[0102] The acquisition node may include an acquisition node acquisition module and a transmission module, which includes 24 acquisition channels in total. Each channel includes a 32-bit analog-to-digital converter, which is used to collect the seismic analog signal received by the hydrophone, and filter, amplify, and digitally convert the signal. After the acquisition work begins, the digital package collects the artificial reflection seismic signals sensed by the hydrophones in the front and rear towed cable working sections, and sends the collected seismic data to the upper working node. In addition to realizing the data and transmission acquisition functions, the digital package also has status monitoring and system self-test functions. The detection contents mainly include: static noise, DC bias, channel crosstalk, total harmonic distortion, hydrophone leakage resistance, gain error, pulse response, etc. The monitoring status parameters mainly include: temperature, air pressure, voltage, and current.

[0103] In some embodiments, the acquisition module is provided with a self-check module for checking the acquisition parameters of the acquisition system. Before normal data acquisition, a self-check can be performed as needed to meet the requirements for accurate acquisition of seismic wave signals and ensure high reliability of the acquired data. Figure 5 As shown, Figure 5 The following is the workflow diagram of the acquisition module. The acquisition module selects the working mode according to the command of the recording system. When the acquisition module receives the self-test command issued by the recording system, the self-test module will generate the standard reference signal required for self-test, and the system will enter the self-test mode. If the acquisition module does not need to perform self-test, the system will enter the normal data acquisition work and configure the signal acquisition module to enter the normal acquisition mode. Finally, the collected data is uploaded to the transmission module.

[0104] The transmission mode of all digital signals uploads the collected data of all channels of the system to the recording system by uploading them step by step. The seismic data is transmitted step by step from the tail to the lumping module in a pipeline manner. The transmission module in each acquisition node, the forwarding module at the front end of cable 2, cable 3 and cable 4, and the lumping module at the front end of cable 1 are all equipped with equalizers and isolation transformers. When the data stream is transmitted over a long distance, it will be subject to strong signal attenuation and noise interference. The equalizer can provide compensation for the signal loss so that the received seismic data signal can be restored to its original strength. The isolation transformer can isolate the interference effect on the local transmission module on the communication link and isolate and protect the transmission / forwarding module.

[0105] In some specific embodiments, the forwarding module includes: a second control unit, a first driver chip, two second driver chips, a first balancing chip, two second balancing chips, a first isolation transformer, two second isolation transformers, two clock data recovery chips, a reset circuit, a crystal oscillator circuit, a JTAG download circuit, and a power supply circuit;

[0106] Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, two of the second driving chips, two of the clock data recovery chips, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module;

[0107] The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node;

[0108] The two second driving chips are respectively connected to one second isolation transformer, the two second balancing chips are respectively connected to one clock data recovery chip and one second isolation transformer, and the two second isolation transformers are respectively connected to the corresponding upper transmission module.

[0109] For example, the forwarding module structure is as follows: Figure 6 As shown, it is composed of FPGA, driver, equalizer and isolation transformer. The function of the forwarding module of the forwarding node is to receive the synchronization information and command information transmitted by the upper forwarding node, forward it to the lower forwarding node on the one hand, and forward it to the collection node of the current working section on the other hand; receive the data information uploaded by the collection node of the current working section and the data information uploaded by the lower forwarding node, and upload this data information to the upper forwarding node.

[0110] More specifically, Figure 7 This is another example structure diagram of the forwarding module of the forwarding node. The hardware of the forwarding node forwarding module and the hardware of the collection node transmission module are basically the same in composition, and are also composed of FPGA, FPGA peripheral circuit, driver chip, equalization chip, isolation transformer, clock data recovery chip and power supply. However, the forwarding node is a dual-level data transmission node, receiving data from the lower-level forwarding node and the collection node of the current working section, and forwarding commands and synchronization information to the lower-level forwarding node and the collection node of the current working section, so a two-way transmission circuit is designed.

[0111] The functions of each part of the hardware circuit of the forwarding module of the forwarding node can be completely consistent with those of the transmission module of the acquisition node. Similarly, the forwarding module of the forwarding node receives commands and synchronization information in the same way as the transmission module of the acquisition node, but when forwarding the commands and synchronization information, they are sent to the lower-level forwarding node and the current-level acquisition node respectively after passing through two driver chips and isolation transformers. The data of this working section enters the clock data recovery chip after passing through the isolation transformer and the equalization chip, recovers the clock from the data, and inputs the recovered clock and recovered data into the FPGA. After the data of the two acquisition nodes of this working section are received, they are framed and sent, and uploaded to the upper-level node after passing through the driver chip and isolation transformer. The data of the lower-level forwarding node enters the clock data recovery chip after passing through the isolation transformer and the equalization chip, recovers the clock from the data, and inputs the recovered clock and recovered data into the FPGA. After FPGA framing, it is uploaded to the upper-level node after passing through the driver chip and isolation transformer.

[0112] As an optional implementation, the lumped node is connected to the recording system on the power device via an optical fiber;

[0113] The centralized node includes the forwarding node and a first optoelectronic transceiver module.

[0114] The lumped module and the forwarding module are different in interface. Since the lumped module needs to be connected to the leading segment for long-distance high-speed data transmission, the data between the lumped module and the recording system is transmitted via optical fiber. The structure of the forwarding node lumped module is as follows: Figure 8 As shown in the figure, it is composed of FPGA, driver, equalizer, isolation transformer and optoelectronic transceiver module. Among them, the optoelectronic transceiver module converts the electrical signal into an optical signal and sends it to the recording system through the optical fiber. The other parts have the same function as the forwarding module of the forwarding node.

[0115] Fig. 9 This is another example structure diagram of the forwarding node lumped module. The hardware of the forwarding node lumped module and the hardware of the forwarding node forwarding module are slightly different in composition. The forwarding node of working segment 1 is connected to the leading segment, and the leading segment uses optical fiber for data transmission. Therefore, the forwarding node lumped module must have a photoelectric conversion function. The forwarding node lumped module consists of FPGA, FPGA peripheral circuit, driver chip, equalizer chip, isolation transformer, clock data recovery chip, photoelectric transceiver module and power supply. An optoelectronic transceiver module is added to the hardware circuit of the forwarding node lumped module, which converts the electrical signal of the data into an optical signal through the optoelectronic conversion module, and sends the data to the recording system through the leading segment.

[0116] In summary, forwarding nodes can be divided into forwarding modules and lumping modules according to their position and function. The lumping module is mainly used to receive the seismic data of the digital package corresponding to the forwarding module and the seismic data of the digital package corresponding to itself, and then transmit the data in a pipeline manner through the underwater wet-end photoelectric conversion cabin and the surface dry-end photoelectric conversion cabin to the recording system in sequence, and finally to the industrial computer. In addition to the data transmission function, the forwarding node also has its own state monitoring function such as temperature, air pressure, voltage, and current.

[0117] Next, the recording system of the embodiment of the present application is further described, and the recording system includes: a host computer, a data transmission interface, a third control unit, an equalizer, a driver, a second optoelectronic transceiver module and a third isolation transformer;

[0118] Wherein, one end of the data transmission interface is connected to the host computer, and the other end of the data transmission interface is connected to the third unit;

[0119] The third control unit is also connected to the equalizer, the driver, the GPS system, the NTP server and the source system respectively;

[0120] One end of the third isolation transformer and the second optoelectronic transceiver module is connected to the lumped node,

[0121] The other end of the third isolation transformer is connected to the equalizer, and the other end of the second optoelectronic transceiver module is connected to the driver.

[0122] For example, refer to Fig.10 The recording system may include a high-speed data transmission interface, FPGA, equalizer, driver, isolation transformer and optoelectronic transceiver module. The host computer sends commands and synchronization information to the FPGA via the high-speed data transmission interface, and after being processed inside the FPGA, it is sent to the lumped module through the equalizer. The data transmitted through the optical fiber passes through the optoelectronic transceiver module, driver and FPGA, and is uploaded to the host computer by the high-speed data transmission interface for storage and display. The GPS system sends location information, the NTP server sends the reference master clock, and the source system communicates with the FPGA via the TTL level.

[0123] The embodiment of the present application provides a seismic data acquisition system based on a "single leading segment-multiple working segments" right-angle comb topology structure, and the technical means include:

[0124] (1) High signal-to-noise ratio signal acquisition. The hydrophone used in the embodiment of the present application is a piezoelectric hydrophone, and the collected signal is a weak underwater seismic sound wave. High signal-to-noise ratio signal acquisition can improve the accuracy of subsequent signal processing and make the exploration results more complete and accurate.

[0125] (2) Long-distance high-speed data transmission. The acquisition system has a single leading segment and multiple working segments structure. Multi-channel hydrophone acquisition is performed through a single acquisition node. The maximum sampling frequency of the acquisition node is 4 kHz. The data volume of a single acquisition node and forwarding node is large, and the transmission distance of the acquisition node is long. The system ensures reliable long-distance high-speed data transmission.

[0126] (3) High-precision synchronous sampling. The synchronous sampling error between acquisition channels will affect the subsequent signal processing and seismic data inversion results of the system. It is very important to ensure the synchronous sampling of all hydrophone channels. A high-precision synchronous sampling method combining the short-term stability of the node local asynchronous drive clock and the master-slave synchronous calibration of the local sampling clock is adopted. The local clock of the acquisition node drives the Σ-Δ ADC sampling, and the master clock sent down is used as a periodic calibration signal to synchronize and calibrate the local clock to achieve synchronous sampling.

[0127] (4) Real-time storage and display of seismic data. After data acquisition, it is uploaded to the shipboard system for real-time storage and display, ensuring that the small three-dimensional high-resolution marine seismic exploration system can store data in real time and accurately, and echo waveform information on the system software.

[0128] Next, the scheme of the embodiment of the present application will be introduced and explained in detail in conjunction with a specific example of seismic data collection and transmission.

[0129] For example, Fig.11 This is an example diagram of the communication structure of the acquisition system of this embodiment.

[0130] Based on the right-angle comb system topology of "single leading segment-multiple working segments", the low-speed-high-speed hybrid pipeline data transmission model has a total of 4 working segments, with 2 acquisition nodes and 1 forwarding node on each working segment. Data is transmitted from the lower node transmission module to the upper node transmission module in the working segment acquisition node in a low-rate single-step manner, and is transmitted to the forwarding node aggregation module in the cross-segment forwarding node in a high-rate double-step manner, and uploaded to the recording system through a single leading segment. The working segment acquisition node only sends seismic data of one acquisition node at a time, so the working segment uses a lower transmission rate. The cross-segment forwarding node sends the data of the entire working segment at a time, so the cross-segment uses a higher transmission rate. Finally, the aggregation module sends the data of all acquisition nodes of the exploration system to the recording system through the leading segment.

[0131] The hardware structure of the acquisition node transmission module,The hardware of the acquisition node transmission module consists of FPGA, FPGA peripheral circuit, driver chip, equalization chip, isolation transformer, clock data recovery chip and power supply.

[0132] Among them, FPGA controls the entire data transmission process of the acquisition node transmission module, including the reception, identification and issuance of downlink command information, the reception and issuance of downlink synchronization information, the reception and upload of local data, and the reception and upload of data from the lower-level acquisition node. The FPGA peripheral circuit includes a crystal oscillator, a reset circuit and a JTAG download circuit. The crystal oscillator provides a working clock for the FPGA, the reset circuit restores the initial state of the circuit, and the JTAG download circuit completes program burning and debugging. The equalizer chip receives data. After the data is transmitted over a long distance, the signal will be attenuated. The equalizer chip balances and shapes the data to restore the data to the state when it was sent. The driver chip sends data, drives the transmission signal, and adjusts the voltage of the output signal at the transmitting end to reduce the attenuation of the signal. The isolation transformer can not only enhance the signal and reduce signal attenuation, but also isolate external electromagnetic interference signals and high voltages, thereby improving the anti-interference and anti-risk capabilities of the circuit board. The clock data recovery chip recovers the clock signal from the serial data and provides a working clock for data processing inside the FPGA. The power supply provides power for all the above circuits, including 5V, 3.3V, 2.5V and 1.2V.

[0133] The commands and synchronization information sent by the forwarding node first pass through the isolation transformer of the transmission module of the acquisition node, and then are input into the FPGA after the signal is shaped by the equalizing chip. On the one hand, the FPGA receives and parses the command, and on the other hand, it forwards the command and synchronization information, and sends it to the lower-level acquisition node after passing through the driver chip and isolation transformer. The data of the lower-level acquisition node also enters the clock data recovery chip after passing through the isolation transformer and the equalizing chip, recovers the clock from the data, and inputs the recovered clock and recovered data into the FPGA. The FPGA receives and frames the data for transmission, and uploads it to the upper-level node after passing through the driver chip and isolation transformer. The acquisition module of the local acquisition node directly sends the data to the FPGA, which receives and frames the data for transmission, and uploads it to the upper-level node after passing through the driver chip and isolation transformer.

[0134] The beneficial effects of this embodiment may include:

[0135] 1. The underwater working structure of a single leading section and multiple working cables is adopted. This structure has only one leading section, and a forwarding node is added at the front end of each working section. In terms of signal acquisition, the acquisition module and the transmission module are separated from the hydrophone channel. One acquisition node receives multi-channel hydrophone analog signals, reducing the number of acquisition nodes in the system. In terms of data transmission, after the acquisition module completes data acquisition, the transmission module frames the multi-channel data and uploads it. The forwarding node forwards the data of the entire working section to the previous level forwarding node for upload, and uploads it to the recording system through a single leading section.

[0136] 2. The number of working cables laid by the underwater working structure with a single leader section and multiple working cables is less restricted by the onboard facilities, has strong scalability and flexibility, and inherits the advantages of the exploration structure with multiple leader sections, multiple working sections, and multiple channels of hydrophones; only one leader section is retained, which solves the problem of multiple leader sections being entangled near the exploration ship; at the same time, the single leader section also leaves sufficient space for the deployment of the source system, meeting the target requirements of the small three-dimensional seismic acquisition system.

[0137] 3. Low construction cost and high cost performance. Breaking through the conventional 3D seismic data acquisition and transmission and underwater equipment expansion towing mode, the data collected by multiple seismic cables are combined and transmitted back through the underwater lumping module, completely getting rid of the limitation of the number of ship-borne winches and leading sections on the cable capacity, combined with the independently designed small 3D seismic underwater equipment towing and retracting technology, it greatly reduces the requirements and production costs of 3D seismic ships and equipment, and effectively expands the number of cables and survey capabilities of existing 3D ships.

[0138] The embodiments described in the embodiments of the present application are intended to more clearly illustrate the technical solutions of the embodiments of the present application and do not constitute a limitation on the technical solutions provided in the embodiments of the present application. Those skilled in the art will appreciate that with the evolution of technology and the emergence of new application scenarios, the technical solutions provided in the embodiments of the present application are also applicable to similar technical problems.

[0139] Those skilled in the art will appreciate that the technical solutions shown in the figures do not constitute a limitation on the embodiments of the present application, and may include more or fewer components than shown in the figures, or a combination of certain components, or different step components.

[0140] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0141] It should be understood that in the present application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or multiple.

[0142] The preferred embodiments of the present invention are described above with reference to the accompanying drawings, but the scope of the rights of the present invention is not limited thereto. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present invention should be within the scope of the rights of the present invention.

Claims

1. A seismic data acquisition system, characterized in that: The seismic data acquisition system comprises: a power device, at least two streamers, and at least two streamer expanders; Wherein, each of the towline extenders is connected to one end of a towline, and the other end of each towline is connected to the power device; The ends of the tow cables are connected by transverse jumper cables, and the two outermost ends are also connected to a tow cable expander by a rein respectively; Each of the streamers includes a forwarding node, a plurality of working sections, a plurality of collecting nodes and a plurality of connecting sections; wherein the forwarding node is connected to one of the working sections, the working sections are connected via the connecting sections, and the collecting nodes are respectively arranged in the working sections; the forwarding node serves as the end; one of the forwarding nodes connected to the streamer extender serves as a lumped node; the lumped node establishes a communication connection with the recording system on the power device; The power device is used to drive each of the towline extenders to move through the towline, so as to drive each of the towlines to move; The acquisition node is used to acquire seismic data; The forwarding node is used to forward the seismic data collected by each of the collection nodes on the streamer to the lumping node; The lumped node is used to transmit the seismic data collected by each of the collection nodes on each of the streamers to the recording system.

2. A seismic data acquisition system according to claim 1, characterized in that: A plurality of hydrophones are arranged in the working section; The acquisition node includes an acquisition module, a transmission module and a first power supply module; Wherein, the acquisition module is used to acquire data acquired by each of the hydrophones in the working sections on both sides of the acquisition node as the seismic data; The transmission module is used to transmit the seismic data collected by the acquisition module at this level and / or the acquisition module at a lower level to the transmission module at an upper level or the forwarding node; The first power supply module is used for supplying power.

3. A seismic data acquisition system according to claim 2, characterized in that: The acquisition module includes: a first control unit, a synchronization control circuit, a state monitoring circuit, a plurality of analog-to-digital conversion circuits, and a digital-to-analog conversion circuit; Wherein, the first end of each of the analog-to-digital conversion circuits is connected to one of the hydrophones, the second end of each of the analog-to-digital conversion circuits is connected to the digital-to-analog conversion circuit, the third end of each of the analog-to-digital conversion circuits is connected to the synchronization control circuit, and the fourth end of each of the analog-to-digital conversion circuits is connected to the first control unit; The synchronization control unit is also connected to the first control unit, and the first control unit is also connected to the state monitoring circuit and the transmission module respectively.

4. A seismic data acquisition system according to claim 2, characterized in that: The transmission module includes: a second control unit, a first driving chip, a second driving chip, a first balancing chip, a second balancing chip, a first isolation transformer, a second isolation transformer, a clock data recovery chip, a reset circuit, a crystal oscillator circuit, a JTAG download circuit and a power supply circuit; Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, the second driving chip, the clock data recovery chip, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module; The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node; The second driving chip is also connected to the second isolation transformer, the second equalizing chip is respectively connected to the clock data recovery chip and the second isolation transformer, and the second isolation transformer is also connected to the upper transmission module.

5. A seismic data acquisition system according to claim 1, characterized in that: The forwarding node includes a forwarding module and a second power supply module; The forwarding module is used to forward the seismic data collected by each collection node of the current streamer and / or the previous streamer to the forwarding module of the next streamer or the lumping node; The second power supply module is used for supplying power.

6. A seismic data acquisition system according to claim 5, characterized in that: The forwarding module includes: a second control unit, a first driver chip, two second driver chips, a first balancing chip, two second balancing chips, a first isolation transformer, two second isolation transformers, two clock data recovery chips, a reset circuit, a crystal oscillator circuit, a JTAG download circuit and a power supply circuit; Wherein, the second control unit is respectively connected to the first driving chip, the first equalizing chip, two of the second driving chips, two of the clock data recovery chips, the reset circuit, the crystal oscillator circuit, the JTAG download circuit and the acquisition module; The first driving chip and the first balancing chip are also connected to the first isolation transformer respectively, and the first isolation transformer is also connected to the lower-level transmission module or the forwarding node; The two second driving chips are respectively connected to one second isolation transformer, the two second balancing chips are respectively connected to one clock data recovery chip and one second isolation transformer, and the two second isolation transformers are respectively connected to the corresponding upper transmission module.

7. A seismic data acquisition system according to claim 1, characterized in that: The lumped node is connected to the recording system on the power device via an optical fiber; The centralized node includes the forwarding node and a first optoelectronic transceiver module.

8. A seismic data acquisition system according to claim 7, characterized in that: The recording system includes: a host computer, a data transmission interface, a third control unit, an equalizer, a driver, a second photoelectric transceiver module and a third isolation transformer; Wherein, one end of the data transmission interface is connected to the host computer, and the other end of the data transmission interface is connected to the third unit; The third control unit is also connected to the equalizer, the driver, the GPS system, the NTP server and the source system respectively; One end of the third isolation transformer and the second optoelectronic transceiver module is connected to the lumped node, The other end of the third isolation transformer is connected to the equalizer, and the other end of the second optoelectronic transceiver module is connected to the driver.

9. A seismic data acquisition system according to claim 1, characterized in that: The forwarding node and the central node are further used to receive and / or forward commands sent by the recording system.

10. A seismic data acquisition system according to any one of claims 1 to 9, characterized in that: The seismic data acquisition system also includes a floating body; One end of the floating body is connected to the power device, and the other end of the floating body is connected to each of the towing cables.

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