Seabed ground survey system
The submarine ground exploration system addresses the challenge of precise weight dropping on the deep-sea seabed by using a device with a suspension and buoyancy mechanism, enabling accurate wave generation and vibration measurement for effective geological exploration.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- OYO CORP JP
- Filing Date
- 2025-12-18
- Publication Date
- 2026-07-09
AI Technical Summary
Existing techniques face challenges in accurately dropping a weight to generate surface waves at a desired position on the deep-sea seabed due to ocean currents, making it difficult to conduct effective ground exploration.
A submarine ground exploration system with a device that holds a weight at a predetermined height from the seabed, detachably connects it via a suspension portion, and includes a buoyancy generation portion to ensure precise dropping and measurement of seabed vibrations.
Enables generation of surface waves at a desired location on the seabed, allowing for accurate geological exploration and improved data quality through controlled weight dropping and vibration measurement.
Smart Images
Figure JP2025044402_09072026_PF_FP_ABST
Abstract
Description
Submarine Ground Exploration System
[0001] This disclosure relates to a submarine ground exploration system.
[0002] Non-Patent Document 1 describes a technique for performing surface wave exploration by arranging submarine seismometers in a linear array and dropping a weight from the water surface to the shallow-depth seabed.
[0003] Yuko Matsubara, Yasuhiro Asano, Mikihiro Imai, Yusuke Inoue, Atsushi Hiraide (2023): Development of Microtremor Array Exploration in Deep-Sea Seabed for Floating Offshore Wind Power, Proceedings of the 148th Academic Lecture of the Society of Exploration Geophysicists, 5-8.
[0004] However, when dropping a weight from the water surface, the weight is carried away by the ocean current before reaching the seabed. Therefore, it has been difficult to drop the weight at a desired position on the seabed. In particular, although ground exploration is required at the seabed in deep water, it is even more difficult to generate surface waves at a desired position on the deep-sea seabed.
[0005] In view of such points, an object of the present disclosure is to provide a submarine ground exploration system capable of generating surface waves at a desired position on the seabed.
[0006] The submarine ground exploration system according to the first aspect of the present disclosure includes: (1) a device that holds a weight at a predetermined height from the seabed and disconnects and drops the weight by remote operation; and a vibration receiver disposed near the device for measuring the vibration of the seabed.
[0007] The submarine ground exploration system according to one embodiment of the present disclosure is the submarine ground exploration system according to (1) above, wherein (2) the device includes a mounting portion mounted on the seabed, a suspension portion connected to the mounting portion for detachably holding the weight, and a buoyancy generation portion that applies an upward force to the suspension portion.
[0008] The submarine ground exploration system according to one embodiment of the present disclosure is the submarine ground exploration system according to (2) above, wherein (3) the device disconnects the connection between the mounting portion and the suspension portion by remote operation, and the suspension portion and the buoyancy generation portion are movable.
[0009] One embodiment of the seabed geotechnical exploration system of the present disclosure is the seabed geotechnical exploration system of the present invention as described in (1) above, wherein the device comprises: a frame placed on the seabed; and a suspension part fixed to the frame and detachably holding the weight.
[0010] One embodiment of the seabed ground exploration system of the present disclosure is the seabed ground exploration system described in (4) above, wherein the device and the vibrator are connected so as to be separable by remote operation.
[0011] One embodiment of the seabed ground exploration system of the present disclosure is the seabed ground exploration system according to any one of (1) to (5) above, further comprising (6) a float connected to the vibrator.
[0012] One embodiment of the seabed ground exploration system of this disclosure is (7) the seabed ground exploration system according to any one of (1) to (6) above, wherein a plurality of the vibrators are provided and the plurality of vibrators are connected in a linear manner.
[0013] One embodiment of the seabed ground exploration system of the present disclosure is the seabed ground exploration system according to any one of (1) to (7) above, wherein the vibrator comprises a memory unit for storing the measured vibrations of the seabed.
[0014] According to this disclosure, surface waves can be generated at a desired location on the seabed to conduct geological exploration.
[0015] This is a schematic diagram showing a seabed geotechnical exploration system according to the first embodiment of this disclosure. This diagram shows the state after the weight has been separated from the suspension part and dropped onto the seabed in the seabed geotechnical exploration system of Figure 1. This is a block diagram showing the configuration of the vibrator in the seabed geotechnical exploration system of Figure 1. This diagram shows the state after the connection between the mounting part and the suspension part has been severed in the seabed geotechnical exploration system of Figure 1. This is a schematic diagram showing a seabed geotechnical exploration system according to the second embodiment of this disclosure. This is a schematic perspective view showing the apparatus of the seabed geotechnical exploration system of Figure 5.
[0016] Embodiments of the present disclosure will be described below with reference to the drawings. In the components shown in the following drawings, the same components are denoted by the same reference numerals.
[0017] A seabed geotechnical exploration system 100 according to a first embodiment of the present invention will be described with reference to Figures 1 to 4. The seabed geotechnical exploration system 100 is installed by a ship 1000.
[0018] The vessel 1000 may tow part or all of the seabed geotechnical exploration system 100 to the installation location. Since the seabed geotechnical exploration system 100 is lightweight, it can be towed by a vessel 1000 with a gross tonnage of about 20 tons. The vessel 1000 may be equipped with means for raising or lowering part or all of the seabed geotechnical exploration system 100. Such means may be a winch.
[0019] The vessel 1000 may be equipped with means such as GPS to measure its own position. The vessel 1000 may be equipped with an acoustic positioning system to measure the position of the seabed ground exploration system 100.
[0020] The vessel 1000 may be equipped with a transceiver for communicating with the seabed geotechnical exploration system 100.
[0021] The seabed ground exploration system 100 comprises a device 10 and a vibrator 20 (20A, 20M, 20N). The seabed ground exploration system 100 may further include a weight 30 and a float (buoy) 40.
[0022] The device 10 holds the weight 11 at a predetermined height from the seabed 2000. This height may be set according to on-site conditions such as the hardness of the seabed 2000 or the exploration depth. This height is, for example, 3 to 5 meters. The weight of the weight 11 is, for example, 50 kg. Specifically, the device 10 may include a mounting section 12, a suspension section 13, and a buoyancy generating section 14. In this disclosure, the seabed also includes lakebeds.
[0023] The mounting section 12 is placed on the seabed 2000. The mounting section 12 may be composed of a weight.
[0024] The suspension section 13 is connected to the mounting section 12. Specifically, the suspension section 13 may be equipped with a rope 13R, with one end of the rope 13R connected to the mounting section 12. By changing the length of the rope 13R, the height of the suspension section 13 from the seabed 2000, and consequently the height of the weight 11 held by the suspension section 13 from the seabed 2000, can be adjusted.
[0025] The suspension section 13 detachably holds a weight 11 that generates surface waves. The suspension section 13 may detachably hold a plurality of weights 11. For example, the suspension section 13 includes a separation mechanism 13S1 in which a screw hole is formed and a means for rotating a screw inserted into the screw hole is provided. The weight 11 is connected to the screw. When the separation mechanism 13S1 rotates the screw, the screw is disengaged from the screw hole. As a result, the weight 11 is separated from the suspension section 13. The separation mechanism 13S1 may include a motor.
[0026] The device 10 remotely detaches the weight 11 from the suspension section 13 and drops it. For example, the separation mechanism 13S1 is equipped with a receiver that receives sound waves. The transceiver on the ship 1000 transmits sound waves including an instruction to detach the weight 11. When the separation mechanism 13S1 receives this instruction, the separation mechanism 13S1 detaches the weight 11 from the suspension section 13 and drops it. The separation mechanism 13S1 may also receive instructions from a location other than the ship 1000.
[0027] Referring to Figure 2, when the weight 11 falls from the suspension part 13 of the device 10 and collides with the seabed 2000, surface waves 2100 are generated on the seabed 2000. By observing and analyzing the surface waves 2100 with the receiver 20, it is possible to estimate, for example, the S-wave velocity structure of the seabed 2000. If the weight is dropped from the water, it is impossible to know where on the seabed 2000 the weight will collide as it is carried away. In contrast, by dropping the weight 11 from the device 10, the weight 11 can be made to collide with the seabed 2000 near the device 10. Generally, when multiple receivers 20 are connected linearly, it is preferable from the viewpoint of data quality, etc., to drop the weight 11 near the end of the row of receivers 20, and preferably on the extension of the row of receivers 20. The position where the weight 11 collides can be adjusted by the length of the rope 20R1 connecting the mounting part 12 and the row of receivers 20. In a configuration where the device 10 holds multiple weights 11, the weights 11 are usually dropped one at a time.
[0028] Furthermore, by connecting the device 10 and the weight 11 with a rope 13R or the like, the weight 11 can be recovered together with the device 10 even after the weight 11 has fallen, as shown in Figure 4. As another example, the weight 11 may not be connected to the buoyancy generating unit 14, but may be connected to the mounting unit 12 and the suspension unit 13.
[0029] The buoyancy generating unit 14 exerts an upward force on the suspension part 13. This configuration prevents the device 10 from tipping over even if a vertically downward force is applied to the suspension part 13. The buoyancy generating unit 14 is connected to the suspension part 13. The buoyancy generating unit 14 may consist of multiple floats 14A, 14B, and 14C. Float 14A and the uppermost float among the floats 14B are connected by a rope 14R1. Multiple floats 14B are connected to each other by a rope 14R2. The lowermost float among the multiple floats 14B and each of the two floats 14C are connected by ropes 14R3 and 14R4.
[0030] In this embodiment, the float 14A floats on the water surface 3000. The float 14A can indicate the location of the seabed ground exploration system 100.
[0031] The receiver 20 is positioned near the device 10 and measures vibrations of the seabed 2000. For example, the receiver 20 can measure surface waves 2100 generated when the weight 11 collides with the seabed 2000. The receiver 20 may acquire the horizontal / vertical spectral ratio of vibrations at its installation location. The receiver 20 may be equipped with sensors to measure the vertical and horizontal components of vibrations and calculate the S-wave velocity based on the horizontal / vertical spectral ratio. The S-wave velocity indicates the softness of the ground at the seabed 2000 and is used as a parameter for seismic design and liquefaction assessment.
[0032] The receiver 20 is connected to the mounting section 12 via a rope 20R1. This configuration maintains a predetermined distance between the receiver 20 and the mounting section 12. Multiple receivers 20 may be provided. Multiple receivers 20A...20M and 20N may be linearly connected via a rope 20R2. This configuration maintains a predetermined distance between adjacent receivers 20. The distance between adjacent receivers 20 may be 2.5 meters or 5 meters.
[0033] The hardware configuration of the receiver 20 will be described in detail below. The receiver 20 may be covered with a protective member. The protective member may be made of glass, for example. Referring to Figure 3, the receiver 20 comprises a control unit 21, a memory unit 22, an attitude control unit 23, and a transponder 24.
[0034] The control unit 21 is one or more processors. The processors are, for example, general-purpose processors or dedicated processors specialized for specific processing, but are not limited to these and can be any processor. The control unit 21 controls the operation of the entire vibrator 20.
[0035] The memory unit 22 stores the vibrations of the seabed 2000 measured by the vibrator 20. The memory unit 22 may also store the time the vibrations were measured. The memory unit 22 is, for example, a storage device that includes one or more memories. The memories are, for example, semiconductor memories, magnetic memories, or optical memories, but are not limited to these and can be any type of memory. The memory unit 22 functions, for example, as a primary storage device or a secondary storage device. When the ship 1000 pulls up the vibrator 20, it can read out the vibrations of the seabed 2000 stored in the vibrator 20.
[0036] The attitude control unit 23 controls the attitude of the receiver 20. The attitude control unit 23 may be composed of a gimbal. By lowering the center of gravity of the receiver 20, the lower surface of the receiver 20 may be placed on the seabed 2000.
[0037] When the transponder 24 receives a specific acoustic vibration, it transmits a response signal. By receiving the response signal from the transponder 24, the position of the transponder 24 can be measured.
[0038] The receiver 20 can also perform micro-vibration array surveys to measure the micro-vibrations of the seabed 2000. These micro-vibrations are thought to be caused by natural phenomena such as waves. Here, the suspension section 13 or the buoyancy generating section 14 moves with the ocean current, causing the seabed 2000 to vibrate via the mounting section 12. These vibrations can interfere with the micro-vibration array survey.
[0039] Referring to Figure 4, the device 10 can remotely disconnect the connection between the mounting section 12 and the suspension section 13. More specifically, the suspension section 13 includes a second separation mechanism 13S2, which has a second screw hole and is provided with means for rotating a screw inserted into the second screw hole. The mounting section 12 is connected to this screw. The second separation mechanism 13S2 rotates the screw, causing it to disengage from the second screw hole. As a result, the connection between the mounting section 12 and the suspension section 13 is disconnected. The second separation mechanism 13S2 may include a motor. After disconnection, vibrations of the seabed 2000 caused by the movement of the suspension section 13 or the buoyancy generating section 14 can be suppressed. Therefore, the accuracy of micro-vibration array exploration can be improved. After disconnection, the ship 1000 can recover the suspension section 13 and the buoyancy generating section 14 connected to the suspension section 13. In a configuration where a weight 11 is connected to the suspension section 13, the ship 1000 can also recover the weight 11.
[0040] Referring to Figure 1, the weight 30 is placed on the seabed 2000. The receiver 20 is connected to the weight 30 via a rope 20R3. The weight of the weight 30 is, for example, 50 kg.
[0041] The float 40 is connected to the weight 30 via a rope 40R. The configuration of the float 40 may be similar to that of floats 14A or 14B. The float 40 can indicate the position of the vibrator 20.
[0042] Next, with reference to Figures 5 and 6, the seabed geotechnical exploration system 200 according to the second embodiment of this disclosure will be described, focusing on the differences from the first embodiment. Note that components having the same configuration in the first and second embodiments are denoted by the same reference numerals.
[0043] The device 210 of the seabed seismic exploration system 200 further comprises a frame 215 and a weight 250.
[0044] The pedestal 215 is placed is placed on the seabed 2000. Referring to FIG. 6, the pedestal 215 is composed of rod-shaped members. The rod-shaped members may be rectangular parallelepiped-shaped or circular tubular. Specifically, the pedestal 215 includes three vertical members 215V extending along the falling direction of the weight 11, three (a total of nine) horizontal members 215H1 and three horizontal members 215H2 extending in each of the three planes orthogonal to the falling direction of the weight 11, and three support members 215I. The members are connected by connecting members 215C.
[0045] The vertical members 215V are connected to each other via the horizontal members 215H1. The support member 215I connects the horizontal member 215H2 and the vertical member 215V. More specifically, the horizontal members 215H1 constitute each side of three small triangles that overlap each other in the direction in which the weight 11 falls. The three vertical members 215V constitute each vertex of the small triangle. The horizontal member 215H2 constitutes each side of a large triangle. The support member 215I constitutes a line segment connecting the vertex of the large triangle and the vertex of the triangle in the middle in the vertical direction among the three small triangles.
[0046] The suspension part 213 is fixed to the pedestal 215. More specifically, the suspension part 213 includes a rod-shaped member 213H extending from one vertex of the uppermost triangle in the vertical direction among the three small triangles to the side opposite to the vertex in the triangle.
[0047] The suspension part 213 may hold a plurality of weights 11 separably. More specifically, the suspension part 213 includes a mechanism 213D in which screw holes are formed and means for rotatably turning a screw inserted into the screw holes is provided. The mechanism 213D is fixed to the rod-shaped member 213H. The weight 11 is connected to the screw.
[0048] The suspension part 213 remotely operates to separate the weight 11 from the suspension part 213 and let it fall. For example, the suspension part 213 includes a receiver 213R that receives sound waves. The transmitter-receiver of the ship 1000 transmits a sound wave including an instruction to separate the weight 11. When the receiver 213R receives the instruction, the device 210 separates the weight 11 and lets it fall. The receiver 213R may receive an instruction from a location other than the ship 1000.
[0049] The weight 250 is placed on the seabed 2000. The separation mechanism 215S of the mounting base 215 is connected to the weight 250 via rope 250R0. The vibrator 20 is connected to the weight 250 via rope 250R1.
[0050] The device 210 and the vibrator 20 may be connected in a way that allows them to be separated by remote control. Specifically, the mount 215 further includes a separation mechanism 215S. The separation mechanism 215S includes a receiver that receives sound waves. The transceiver on the ship 1000 transmits sound waves that include an instruction to separate the device 210 and the vibrator 20. When the receiver receives this instruction, the device 210 separates the vibrator 20. After separation, the vibrator 20 can be recovered while the suspension part 213 and the mount 215 remain on the seabed 2000. Therefore, the accuracy of micro-vibration array exploration using the vibrator 20 can be improved.
[0051] The device 210 may further include a transponder 260. When the transponder 260 receives a specific acoustic vibration, it transmits a response signal. By receiving the response signal from the transponder 260, the position of the transponder 260 can be measured.
[0052] The present invention has been described based on the drawings and embodiments, but it should be noted that those skilled in the art will find it easy to make various modifications or alterations based on this disclosure. Therefore, it should be noted that these modifications and alterations are within the scope of the present invention. For example, the functions, etc., included in each means, each step, etc., can be rearranged in a logically consistent manner, and multiple means or steps, etc., can be combined into one or divided.
[0053] 100, 200: Seabed geological exploration system 10, 210: Device 11, 30, 250: Weight 12: Mounting section 13, 213: Suspension section 13S1, 13S2, 215S: Separation mechanism 13R, 14R1, 14R2, 14R3, 14R4, 20R1, 20R2, 20R3, 40R, 250R0, 250R1: Rope 213H: Rod-shaped member 213R: Receiver 213D: Mechanism 14: Buoyancy generating section 14A, 14B, 14C, 40: Floats 20, 20A, 20M, 20N: Vibrator 21: Control unit 22: Memory unit 23: Attitude control unit 24, 260: Transponder 215: Mounting base 215H1, 215H2: Horizontal member 215V: Vertical member 215I: Support member 215C: Connecting member 215S: Separation mechanism 1000: Ship 2000: Seabed 2100: Surface wave 3000: Water surface
Claims
1. A seabed geological exploration system comprising: a device that holds a weight at a predetermined height above the seabed and remotely detaches and drops the weight; and a vibrator positioned near the device for measuring vibrations of the seabed.
2. The seabed ground exploration system according to claim 1, wherein the device comprises: a mounting section placed on the seabed; a suspension section connected to the mounting section and detachably holding the weight; and a buoyancy generating section that exerts an upward force on the suspension section.
3. The seabed ground exploration system according to claim 2, wherein the device disconnects the connection between the mounting unit and the suspension unit by remote operation, thereby making the suspension unit and the buoyancy generating unit movable.
4. The seabed ground exploration system according to claim 1, wherein the device comprises a frame placed on the seabed and a suspension part fixed to the frame and detachably holding the weight.
5. The seabed ground exploration system according to claim 4, wherein the apparatus and the vibrator are connected so as to be separable by remote control.
6. The seabed ground exploration system according to any one of claims 1 to 5, further comprising a float connected to the vibrator.
7. A seabed seismic exploration system according to any one of claims 1 to 5, wherein a plurality of the aforementioned vibrators are provided and the plurality of the aforementioned vibrators are connected in a linear manner.
8. The seabed ground exploration system according to any one of claims 1 to 5, wherein the vibrator comprises a memory unit for storing the measured vibrations of the seabed.