RU65251U1 - CABLE BOTTOM SEISMIC STATION - Google Patents

Abstract

The proposed utility model of cable bottom seismic station (KDSS) is designed to perform long-term seismological studies.

The essence of the proposed technical solution is to create a CDSS, which allows, for a long time (several years) to conduct in the offshore zone (depth 200-300 m) at the edge of the depth dump to continuously record seismic signals from a three-component seismic sensor and acoustic signals from a low-frequency hydrophone with long-term seismological studies. At the same time, the cable bottom station should be able to return to the sea surface to carry out ongoing repair and maintenance work or to carry out modernization of the station.

A continuous stream of seismic information is supplied to the inpatient facility, and only pulsed signals (earthquake signals) are recorded in the CDSS in the CDSS, according to a certain algorithm.

Description

The technical solution relates to the constructive implementation of marine seismic research tools and can be used for long-term seismological studies.

Autonomous bottom stations are known, which are the equipment carrier body with electronic equipment located inside, a power source and measuring transducers, and out-of-order receiving sensors.

Autonomous bottom seismic station (ADSS), adopted as a prototype, [V.V. Perunov, A.E. Malashenko, V.I. Filimonov, BC Rozhkov, Patent No. 49286, IPC G01V 1/38, publication date 10.11.2005], is a deep-sea equipment carrier (ON), consisting of two hemispheres tightened by bolts on the flanges, to ensure tightness on special grooves cut in a circle, two rubber rubber rings are laid. Inside, the following are installed: on the upper hemisphere, an orientation system block, an on-board computing unit (STB) installed using the instrument ring; on the lower hemisphere, a power source, a tightness sensor, a three-component sesmodic sensor, an urgency device (PS) and a disconnector (the executive part is brought out to a special platform of the lower hemisphere). Outside, in the upper hemisphere, at the site, there is a low-frequency hydrophone, a high-frequency receiver (transceiver hydroacoustic sensor) designed for hydroacoustic communication, a pressure sensor (DD) that determines the station's current immersion depth, a radar reflector and a radio transmitter antenna, a flashing beacon (PM), a satellite antenna radionavigation system (SRNS). A tripod is attached to the lower hemisphere, made of metal pipes and tightly tightened with the help of the actuator part of the disconnector, which is tightened with a nut; ballast shoes are attached to the sole of the tripod. At the same time, part of the tripod returns with the station, and the other part with ballast shoes remains at the bottom. The orientation system block consists of a compass device and a tilt sensor. The readings from the tilt sensor and from the compass device are recorded on the local memory and, by command, can be transferred to the sonar unit in the on-board computing unit.

With undeniable advantages, the prototype has a significant drawback, which consists in limiting the imposed by the power source of the autonomous system for the duration of continuous operation. This applies in particular to systems designed for the long-term recording of information.

For systems designed for long-term continuous recording of information in coastal shelf areas at the border

dump of depths, this disadvantage can be eliminated with the help of cable bottom stations. Using the cables laid along the bottom of the cable, information is collected, commands and power are transmitted to the bottom seismic station

The proposed utility model of cable bottom seismic station (KDSS) is designed to perform long-term seismological studies.

The essence of the proposed technical solution is to create a CDSS, which allows, for a long time (several years) to conduct in the offshore zone (depth 200-300 m) at the edge of the depth dump to continuously record seismic signals from a three-component seismic sensor and acoustic signals from a low-frequency hydrophone with long-term seismological studies. At the same time, the cable bottom station should be able to return to the sea surface to carry out ongoing repair and maintenance work or to carry out modernization of the station, or if necessary, to remove the accumulated seismoacoustic information from the information storage device (NI).

A continuous stream of seismic-acoustic information is fed to the inpatient facility, and only pulsed signals (earthquake signals) are recorded to the information storage device (ND) in the KDSS according to a certain algorithm.

KDSS is (Fig. 1) an equipment carrier (ON) 1, consisting of two hemispheres tightened by bolts 18 on flanges 17, to ensure tightness on special grooves cut in a circle, two rubber rubber rings are laid 16. Inside HA 1 are installed: the upper hemisphere, the orientation system block 5, the on-board computing unit (BVU) 2 installed using the instrument ring 19; on the lower hemisphere, a power source 3, a tightness sensor 20, a three-component seismic sensor 4 and a disconnector 6 (the executive part is brought out to a special platform of the lower hemisphere). Outside, in the upper hemisphere, on the site, using the cable entry 9, a light signal cable 9-1, a low-frequency hydrophone 10, a high-frequency receiver 11 (transceiver sonar sensor) designed for sonar communication, the antenna 12 of the radar reflector and radio transmitter, flashlight are introduced into the station beacon (PM) 13, pressure sensor (DD) 14, which determines the immersion depth of the cable station, antenna 15 of the satellite radio navigation system (SRNS). A tripod 7 is attached to the lower hemisphere, made of metal pipes and tightly tightened using the actuator part of the disconnector 6-1, which is tightened with a nut 6-2, ballast shoes 8 are attached to the base of the tripod. At the same time, part of the tripod 7-1 returns with the station, and 7 -2 with 8 ballast shoes remain at the bottom. The orientation system unit 5 consists of a compass device and a tilt sensor (they are not shown in FIG. 1). Indications from

the tilt sensor and from the compass device are stored in local memory and can be transferred to the control unit (controller) (item 29 in figure 4) in the on-board computing unit 2 for transmission to the hospital via cable and on board the supply vessel via a sonar channel communications (on request from the side of the providing vessel).

The power supply unit (secondary current sources) 3 is assembled from rechargeable batteries, which is continuously recharged from the hospital via an electric cable and provides the necessary series of supply voltages for various blocks and nodes of the cable bottom station. The power supply is installed so that the center of gravity of the assembled station is located on the lower hemisphere to ensure the stability of the cable station on the sea surface. If necessary, the power source provides continuous operation for 3 months.

The tightness sensor 20 represents two contacts that, when interacting with seawater, close the circuit. The tightness sensor is located at the lower point of the lower hemisphere, thus ensuring control of the tightness of the station (when a leak is detected, the circuit closes, thereby giving a command to the control unit for the actuator of the circuit breaker (key 35 in figure 4)).

The actuator of the electromagnetic type 6 breaker, when a current pulse is applied to the electromagnet winding, pulls the core into the glass, while the core releases the hook shank 6-3 and the latter rotates around its axis under the action of tensile force, releasing the earring 6-4. The screw 6-5 and nut 6-2 are designed to select the play between the pop-up part of the tripod 7-1 and part 7-2 remaining at the bottom, which contributes to better transmission of seismic vibrations from the ground to the seismic sensors.

Light signal cable 9-1 (figure 2) is attached to the return frame 7-1 using a special bracket 9-2. With the help of this bracket, a safety rope 9-5 is also attached. Light cable 9-1 has a length corresponding to 1.5-2 times the depth of the place where the station is being set up. One end of cable 9-1 is connected to KDSS using cable entry 9, and the other end of cable 9-1 is connected to connector 9-3, where on the other side is an armored trunk cable 9-4 from the coastal hospital. The coupling connector 9-3 is rigidly connected to the ballast anchor 8-1. The end of the safety rope 9-5 is fixed to the ballast 8-1 using the ring 9-6. This scheme was chosen in order to simplify and reduce the cost of repair and maintenance work. To carry out these works, it is enough to give a command to return ballast 8 on command from the hospital or from the side of the supplying vessel. After the command is completed, the KDSS gives ballast 8 and floats to the surface of the sea. In the event of an emergency ascent, the KDSS is held in the area of arming with an 8-1 ballast. The armored cable was chosen because the usual cable in the coastal zone is quickly frayed due to the interaction of the breaking sea wave and sand, which leads to

to cable outage. This design significantly facilitates the repair and maintenance work.

The on-board computing unit (BVI) 2 includes (Fig. 3): a four-channel filtering and amplification unit (FU) 21, which provides filtering of the signals from the outputs of the three-component seismic sensors and low-frequency hydrophone in the band 1-60 Hz and amplifying the signals for their transmission to the input block of four channel analog-to-digital converter (ChATsP) 22; shaper channels (CF) 23, (CF1) 28; ChATsP triggering pulses are generated in the timer 25; information storage (NR) 24, which is a solid-state (flash) memory with a capacity of about 2 GB; the launch of NI is carried out using a threshold device (PU) 26.

ChATsP block 22 consists of four 14-bit ADCs and has four outputs; the outputs of ChATsP 22 are separately supplied to the input channels of the shaper (KF) 23, (KF1) 28, where an array of a separate sample with a length of sixteen-bit word is formed from the signals from the sensors and the hydrophone (the information occupies the fourteen least significant bits, the oldest 15 and 16 bits form numbers corresponding information channels, with 0 corresponding to channel P, 1 to seismic channel X, 2 to channel Y, 3 to channel Z). For each information channel, a file is created with a length of 250 Kbytes (based on the assumption that the quantization frequency is 200 Hz and with a realization length of 10 minutes, the sales volume is 240 Kbytes, the name of the file is written to the remaining 10 Kbytes, free cells are clogged with zeros, and these 10 Kbytes form the beginning of each file). To eliminate information loss for each channel, a 16-bit (higher 15 and 16 bits characterize the number of the corresponding channel) memory register 27 with a memory capacity of 1024 (1K) cells is provided, from the output of which is then fed to the corresponding input channel of KF 23 and KF1 28 blocks .

From the output of KF 23, information is transmitted using the transmitter through special connectors to the light cable 9-1 and then via the main cable 9-4 to the coastal hospital.

Information is input into NI 24 by a command from the adaptive threshold device 26. Information from the fourth channel of ChATsP 22 corresponding to the vertical component Z of the three-component seismic sensor 4 is fed to the input of the threshold device 26. If the current signal value is exceeded by a certain amount (10 dB) relative to the average value during corresponding to a 1K countdown of the time preceding the current signal time, a command is issued to simultaneously turn on KF1 28 and NI 24. Simultaneously with the output of the threshold device 26 a command is sent to the timer 25 to generate a time code containing a year, month, hours, minutes, seconds, fractions of a second with an accuracy of 0.005 seconds, which is fed to the four channels of the FU 21 block to generate the file name. The length of the input implementation is 10 minutes, selected to register the acoustic component (T-phase)

underwater earthquakes arriving at the registration point noticeably later than seismic longitudinal (P) and transverse (S) waves. If another event occurred during the period of entering information, then from that moment the counter of input samples is reset, and the counter is restarted, while the file name does not change, i.e. Continuous registration of the next event occurs. Thus, in NI 24, all seismic events that satisfy the above algorithm are recorded. Timer 25 represents a digital unit, where “Hyacinth” type quartz is used as a clock generator with the help of which a time code with an accuracy of 0.005 sec and triggering pulses with a frequency of 200 Hz are generated for ChATsP 22.

In the BVI 2 are located (figure 4): in addition to the above-mentioned control unit (BU) 29, the control unit for the actuator of the disconnector (UIM) 35, the unit for hydroacoustic communication (GAS) 34, the space navigation unit (KN) 36, the direction finding and location unit (PL) 37.

The control unit 29 is a microcontroller that controls all KDSS devices by command, from a hospital received via a cable line or by a command received through a hydroacoustic communication channel or via a radio channel (on the sea surface). In the control unit, daily at 00:00 00:00 GMT, the time is adjusted (zeroing the timer). Zeroing is done from the hospital in automatic mode.

According to the signal from the pressure sensor 14 in the above-water position (during emergency ascent), the BU 29 includes a flashing beacon (PM) 13, a bearing and location unit (PL) 37, a KN 36 unit. Block 37 through the antenna 12 periodically emits a continuous tone signal at a standard frequency direction finder, interrupted by a coded message containing the station's conditional number, is at the same time ready to reflect the location signal from a standard ship's radar, which makes it possible to clearly mark the station's location. In the underwater position, according to the signal from the pressure sensor 14, the control unit 29 turns off the above blocks (36 and 37) and turns on the GAS block 34.

BU 29 on command turns on or off, the GAS block 34, executes all the commands received using the GAS block 34 and, if necessary, transmits the requested information through the GAS 34, using the receiver 11. In addition, the control unit 29 controls the registration modes NI 24 at a given command.

If the data from the pressure sensor 14 is exceeded, for example, 1000 meters, or if a leak is detected using the tightness sensor 20, either by the command received from the hospital, or by the command received through the hydroacoustic communication channel using the receiver 11, or when the tilt angle is exceeded 30 degrees in the block of the orientation system 5, the control unit 29 gives the command UYM 28 to turn on the actuator 6 (i.e., the ballast is reset).

Block KN 36 using the antenna SRNS 15 allows the providing vessel, searching for the station, using the satellite radio navigation system, to determine the location of the station.

The work of the KDSS is as follows. Using a special cable-laying vessel, an armored trunk cable is laid from the hospital to the installation site of the KDSS. The end of the armored trunk cable 9-4 is inserted into the coupling connector 9-3. On the other side of the coupling-connector 9-3, the end of the light signal cable 9-1, for the ring 9-6 is attached a safety rope 9-5. Using the halyard 9-5, we install the anchor-ballast 8-1 on the bottom.

On board the supply vessel, before setting up the KDSS, a full training cycle is going on, including the inclusion and testing of various units and blocks. After the preparation cycle, the KDSS is lowered from the side of the supporting vessel overboard using an external crane. The sealed container 1 (Fig. 1) made of aluminum alloys has a maximum working depth of 1000 m. KDSS makes a dulling on a ballast tripod (7, 8). After a certain time, at the command of BU 29, in the block of the orientation system 5, the readings of the compass device and the tilt sensor are recorded, which are recorded on the local memory of the block of the orientation system.

Acquisition of seismic acoustic signals using a low-frequency hydrophone 10 and three seismic receivers 4, oriented in three orthogonal directions X, Y, Z. After conversion, the signals P, X, Y, Z are continuously transmitted in digital form to the hospital via cables 9-1 and 9-4.

When registering signals from earthquakes on the drive (NR) 24, the adaptive threshold device 26 is turned on, which provides with a low probability of missing registration of these signals. At a command from the threshold device 26, the signals are recorded on four channels of NI 24 with a duration of 10 minutes. Each implementation has a file structure, and the file name corresponds to the time of arrival of signals from the earthquake (on channel Z).

When performing repair and maintenance work from the supplying vessel, a command is issued to ascend to the GAS block 34 via the sonar communication channel, these commands are executed by the BU 29, the software device gives the UIM 35 command to return the ballast. In case of failure to complete the commands, the reset command can be duplicated from the hospital via a signal cable.

Emergency ascent of KDSS can be carried out in case of leakage of the station by a signal from the tightness sensor 20, if the KDSS exceeds an immersion depth of 1000 m by a signal from the pressure sensor 14, if the value of 30 degrees is exceeded in the tilt sensor of orientation unit 5 and by a command through the hydroacoustic channel communication through the block GAS 27.

At the moment of ballast recoil (emergency ascent or during repair and maintenance work), the float 32 begins to be mounted directly on tripod 7. The float 32 with wound propylene halyard (halyard length of 15 meters) is designed to take the station aboard the supply vessel. After the ascent, the station turns on the flashing beacon 13 (at night), starts transmitting the radio signal of the bearing through the antenna 12 of the radar reflector and the radio transmitter, the encoded signal through the antenna of the SRNS 15. In the case of receiving a signal from the ship’s radar, the antenna 12 starts working in the active reflector mode. Station found

After the station is sampled, repair and maintenance work is carried out to eliminate defects, replace blocks and units, and upgrade the station on board the supply vessel. If necessary, the accumulated information is removed from NI 24. After performing preventive maintenance, the station is set up according to the above technology.

Claims (2)

1. Cable bottom seismic station (CDSS), which includes an orientation system unit, an on-board computing unit, a power source, a leakage detector, a three-component seismic sensor, a low-frequency hydrophone, a high-frequency receiver (transceiver sonar sensor), a pressure sensor, an antenna of a radar reflector and a radio transmitter, flashing light, antenna of the satellite radio navigation system, disconnector, characterized in that the armored trunk and light signal cables are used. 2. The station according to claim 1, characterized in that the ballast anchor is used with a coupling coupler.