RU2610029C1 - Compact autonomous seismic-acoustic station - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: compact autonomous seismic-acoustic station (CASAS) containing the equipment carrier (AC) mounted on the seabed and popping-up after the ballast recoil, is declared. The equipment carrier AC contains an on-board computing unit (BCU), power supply, a triaxial geophone placed in the sealed spherical container and a hydrophone, a device of setting and taking the AC from the ground, a search tool for the floated AC made in the form of the flashing beacon, of the satellite navigation system "Glonass" of the low-orbit satellite communication system "Gonets", and an active radar reflector, a breaker duplicated by the commands from the urgency device installed outside the sealed container with the tightness sensors, the pressure sensor registering the path consisting of the four-filtration and gain unit providing filtering of the signals from the triaxial geophone and the hydrophone outputs in the frequency band of 5-200 Hz, and the amplification of signals for their application to the input unit of the four-channel analog-to-digital converter (FADC), the output signals from which are served separately on the input channels of the generator (CG), where an array of the separate samples with a length of the sixteen-bit words, supplied from the output of the CG to the respective channels of the information storage (IS), which is a solid-state memory of the four flash cards with a capacity of 2 GB each, is formed from the hydrophone and seismic sensors . The FADC unit consists of four 14-bit ADCs. The device of setting and taking the AC from the ground is made in the form of n pontoons placed in tiers, forming a truncated pyramid and equipped with the cylinders of the compressed gas and the respective inlet and outlet valves. The search tool for the floated AC, made in the form of the flashing beacon, of the satellite navigation system "Glonass" of the low-orbit satellite communication systems "Gonets" and the active radar reflector, are placed in the navigation buoy connected with the CASAS cable-coupling, in which the cable is made in the form of the hydrosensor cable.

EFFECT: provision of the more reliable area studies.

Description

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

The basic principles for constructing autonomous stations oriented to work at great depths are given in (Konovalov S.L.The use of autonomous bottom stations as a universal carrier for measuring equipment. Publishing House GP VNIFTRI, 2000, pp. 135-139 [1] ) Autonomous hydrophysical stations oriented to work at great depths, as a rule, are a robust equipment carrier body designed for a certain hydrostatic pressure and, accordingly, the maximum working depth. Inside the case there is electronic equipment, power supplies and measuring transducers. Transducers can also be located in remote systems, while communication with the equipment is carried out using cable glands. A fully equipped autonomous station should have positive buoyancy, and immersion is due to lost ballast weight, fixed to a controlled ballast disconnector

Known autonomous bottom seismic station (ADSS) (patent RU No. 49286 U1, 10.11.2005 [2]), which is installed on the seabed at depths of up to 6000 m, is protected from the surrounding marine environment by a robust spherical body, equipped with a single hydrophone, digital recording system and information accumulation, telemetric hydroacoustic communication system, station search system on the sea surface, ballast release system, device for program control of operating modes.

The main disadvantage of ADSS is the possibility of registering only three components of seismic channels and significant weight and size characteristics of the equipment carrier (HA) and, as a result, a prerequisite for a supplying vessel is the presence of a powerful crane facility for performing production and sample work.

The experience of using GLONASS satellite navigation systems and Gonets communications was considered in a utility model of an autonomous seismic-acoustic hydrophysical station (ASAGS) (patent RU No. 61895 U1, 03/10/2007 [3]) when performing seismic-acoustic and hydrophysical monitoring over extensive sea areas. During the operation of ASAGS, special vessels are also required here, armed with cranes for carrying out staging and selective work.

It is also known to use flash cards as information storage devices that are sequentially combined as a separate cartridge (WO No. 201032947 A2, 03.25.2002 [4], US No.2002078297, 03.03.2010 [5], US No. 2007181699 A1, 08.09.2007 [ 6]).

Also known ADSS (US No. 6560565 B2, 05/06/2003 [7], US No. 7016260 B2, 03/21/2006 [8], RU No. 2229146 C1, 05/20/2004 [9]) also have a number of significant drawbacks.

Also known is a small-sized autonomous seismic-acoustic station (MACAS), designed for seismic-acoustic studies on the shelf when performing exploration of oil and gas fields (patent RU No. 2540454 C2, 02/10/2015 [10]), selected as a prototype.

The essence of the known technical solution [10] lies in the creation of the MASAS, which performs registration of seismic acoustic signals from the outputs of a three-component seismic receiver and hydrophone. To use the seamless geological model, the MASAS can be installed both on land and on the shelf at depths of up to 500 m. When working on land, MASAS can be used with the acoustic channel disconnected. Such a scheme of using the MASAS allows conducting wide area studies using the methods of CMPW and MOB. When performing on-site exploration, dozens of synchronously operating MASAS are required. Therefore, the following requirements are imposed on MASAS: simplicity in operation; relatively low cost; small weight and size parameters, allowing manual station production and sampling using small vessels. Reliable station return is provided using: duplicate actuator commands; light beacons; active beacons; a satellite navigation system of the Glonass type and a low-orbit satellite communication system of the Gonets type. The capacity of continuous recording of digitized information up to 60 days, which is ensured by a solid-state memory of four flash cards with a capacity of 20 GB each. The modern elemental base allows to significantly reduce the weight and size parameters of devices. MASAS has the following weight and size parameters: outer diameter of the carrier - 350 mm; station weight - 13 kg; ballast weight - 20 kg.

Known MASAS [10] is (Fig. 2 and Fig. 3 prototype) an ellipsoid structure (working depth up to 500 m) equipment carrier (ON), consisting of two hemispheres and a cylindrical insert (upper hemisphere made of radiolucent materials, lower the hemisphere is made of aluminum alloys, between the hemispheres a cylindrical insert made of aluminum alloys), tightened with bolts on the flanges, to ensure tightness on special grooves cut in a circle, two rubber sealing rings are laid.

Inside the AT are installed: receiving antennas of satellite navigation and communication systems; on-board computing unit (STB) with an information storage device mounted on the instrument ring; on the lower hemisphere - a power source; two horizontal and vertical components of the seismic receiver and an urgency device (PS) located in the housing, and an electrochemical disconnector, the executive part of which is brought out to a special area of the lower hemisphere. Outside, on the upper hemisphere, on special sites of the upper square frame, the following are installed: hydrophone; radar reflector antenna; flashing beacon (PM). A device for rigid landing on the ground, made of metal pipes, rigidly pulled together with the help of the actuator part of the disconnector, is attached to the area of the lower square frame; ballast shoes are attached to the sole of the device. When the MACAS ascends, the device with ballast shoes remains at the bottom. The power source is assembled from lithium rechargeable batteries, which currently provide the maximum capacity per standard unit of weight and size batteries. The power source is installed so that the center of gravity of the assembled station is located on the lower hemisphere to ensure the stability of the station on the sea surface. To ensure reliable stability of the MACAC on the sea surface when working with satellite navigation and communication systems, an additional load is fixed on the lower part of the hull. When sampling the MASAS on board the vessel, a special capture device is used, the base of which is rigidly fixed to the platform of the upper square frame, and the tip is attached to the end of the halyard, the other end of the halyard is attached to the float. In the transport version, the halyard is wound on a float; the length of the halyard is 15-20 m.

The stand-alone urgency device is an electronic timer with an autonomous power source for directly actuating the actuator of the circuit breaker.

When a current is applied to the circuit breaker, the electrochemical-type disconnect mechanism operates for several minutes, thereby freeing the MACAS from a hard-landing device with ballast shoes.

Possessing significant advantages over similar technical solutions [1–9] in terms of performing the MASAS in a small-sized version, at the same time, the well-known MASAS [10] has significant disadvantages. The main disadvantage is that the ballast is made in the form of shoes.

When placing the carrier of the measuring equipment on an uneven bottom, as well as in the presence of underwater currents, the carrier of the measuring equipment can take an unstable position, and when a combination of adverse underwater conditions can fall on its side.

In addition, the presence of hard landing devices spaced apart by small distances in the presence of underwater currents can cause the appearance of unwanted additional acoustic noise.

The disadvantages include the placement of the equipment carrier directly on the hard landing device, which does not exclude the influence on the quality of registration of seismic signals of bottom currents, which sway the hard landing device together with the carrier of the equipment and cause vortex noise around thin-sized elements of the underwater structure.

The use of tools to search for a pop-up ND, made in the form of a flashing beacon, a satellite navigation system of the Glonass type, a low-orbit satellite communication system of the Gonets type and an active radar reflector, leads to an increase in labor costs in the manufacture of MACAS, and the resulting positive effect is not always can be achieved.

The objective of the proposed technical solution is to increase the reliability of registration of seismic signals.

The problem is solved due to the fact that in a small-sized autonomous seismic-acoustic station (MACAS), which contains the equipment carrier (NA) that pops up on the seabed after ballast delivery, and the ON includes an on-board computing unit (BVU) located in a sealed spherical container, the source power supply, three-component seismic receiver, as well as a hydrophone installed on the outside of the sealed container, a device for setting up and removing NA from the ground, means for searching for a pop-up NA, made in the form of a lighthouse, a Glonass-type satellite navigation system, a Gonets-type low-orbit satellite communications system and an active radar reflector, a circuit breaker duplicated by commands from an urgency device, an air tightness sensor, and a pressure sensor that records a path consisting of a four-channel filtering and amplification unit filtering the signals from the outputs of the three-component geophones and hydrophone in the frequency band 5-200 Hz and amplifying the signals for supplying them to the input of the four-channel analog-qi block a level converter (CACP), the output signals from which are separately supplied to the input channels of the shaper (KF), where from the signals of the hydrophone and geophones an array of a separate sample is formed with a length of sixteen-bit words fed from the output of the KF to the corresponding channels of the information store (NI), which is a solid-state memory of four flash cards with a capacity of 2 GB each, and the CACP unit consists of four 14-bit ADCs, the device for setting and removing the AT from the ground is made in the form of n pontoons, tiers that form a truncated pyramid and are equipped with compressed gas cylinders and corresponding inlet and outlet valves, means for searching for a pop-up ND made in the form of a flashing beacon, a satellite navigation system of the Glonass type, a low-orbit satellite communication system of the Gonets type and an active radar reflectors are placed in a navigation buoy connected to the MACAC by a hitch cable, in which the cable is made in the form of a sensor cable.

Blocks and devices that implement the corresponding signs of the restrictive part of the known technical solutions can be performed similarly to the corresponding blocks and devices of the prototype [10].

In contrast to the prototype [10], in the proposed technical solution, the device for setting up and removing ND from the ground is made in the form of n pontoons placed in tiers, forming a truncated pyramid and equipped with compressed gas cylinders and corresponding inlet and outlet valves, means for searching for the surfaced ND made in the form of a flashing beacon, a satellite navigation system of the Glonass type, a low-orbit satellite communication system of the Gonets type and an active radar reflector, are placed in a navigation buoy associated with M ACAC cable-hitch, in which the cable is made in the form of a sensor cable.

The device for placing and removing ND from the ground, made in the form of n pontoons placed in tiers, forming a truncated pyramid and equipped with compressed gas cylinders and corresponding inlet and outlet valves, provides the mobility of MACAC placement, allowing the installation of MACAC directly on the ground and making appropriate measurements on several levels along the depth of immersion, adjusting the buoyancy of the MACAS, by means of a device for setting up and removing scientific equipment from the ground with the ability to hold a given underwater horizon by means of fastened pontoons connected by hoses to a cylinder with a compressed gas and a water pump.

The cable is a hydro-sensor cable, in which wires with a sheath made of transenergoplastics - a highly conductive flexible polymer composite of the EMISTOP type (Unusual plastics - new solutions / Repair * Innovations * Technology * Modernization // Rhythm, October 2014, p. Are used as a key sensor element) . 10-12), which allows, thanks to the polymer base of the sensor cores, to provide respectively the flexibility and high chemical resistance of the cable. Moreover, such a cable is not susceptible to corrosion for a long time and can operate in a humid environment.

Each cable consists of two parallel flexible sensor elements - energized metal cores with a sheath of highly conductive plastic. From the mutual closure of the veins are protected by a dielectric plastic rod entwined around the veins in the form of eights. The whole structure is placed in a “sorption” case made of a capillary-porous fibrous material with dielectric properties in a dry state.

The sorption cable operation scheme is as follows. Water in contact with the cover due to the combination of sorption and capillary-porous effects begins to be absorbed (spread throughout the thickness of the cover), forming a set of electrically conductive, mutually penetrating microchannels. Ultimately, these microchannels close the electrically conductive surfaces of the two sensor elements. When a short circuit is generated, an electrical signal is generated, which is transmitted further along the metal core of the sensor elements. After the appropriate signal processing procedure, a message about the flooding and its coordinates appears on the control panel.

The work of MASAS is as follows. On board the supply vessel, before setting up the MACAS, a full training cycle is going through, including the inclusion and testing of various units and blocks, and entering the station's work program into a software device. After the preparation cycle, the MASAS is lowered from the side of the supporting vessel overboard using an external crane. Depending on the MACAS production horizon, the pontoons are filled with overboard water and the MACAS starts diving at an average speed of 1.5-1.6 m / s. The sealed container, made in the form of an ellipsoid or spherical shape, has a maximum working depth of 500 m. The MACAC is installed using a hard landing device on the ground to the bottom. Acoustic seismic signals are received using a hydrophone and three-component seismic receivers oriented in three orthogonal directions X, Y, Z. Signals are recorded on four SR channels.

After a given cycle of recording seismic signals, the MACAC rises to the surface by removing water from the pontoons.

The advantage of the proposed technical solution is the ability to register seismic signals not only when the MACAS is on the ground, but also at predetermined immersion horizons.

The positive effect also lies in the fact that, if necessary, a continuous mode of determining the position of the MACAC is provided, and, in addition, the ballast, made in the form of pontoons, does not remain on the seabed.

Information sources

1. Konovalov S.L. The use of autonomous bottom stations as a universal carrier of measuring equipment. Publishing House of the State Enterprise "VNIFTRI", 2000, p. 135-139.

2. Patent RU No. 49286 U1, 10.11.2005.

3. Patent RU No. 61895 U1, 03/10/2007.

4. Application WO No. 201032947 A2, 03.25.2002.

5. Application US No.2002078297, 03/25/2010.

6. Application US No. 2007181699 A1, 08/09/2007.

7. US patent No. 6560565 B2, 05/06/2003.

8. US patent No. 7016260 B2, 03.21.2006.

9. Patent RU No. 2229146 C1, 05.20.2004.

10. Patent RU No. 2540454 C2, 02/10/2015.

Claims (1)

A small-sized autonomous seismic-acoustic station (MACAS), which contains an equipment carrier (HA) that pops up on the seabed after ballast delivery, and includes an on-board computing unit (BWI) located in a sealed spherical container, a power supply, a three-component seismic receiver, and also installed outside a sealed container hydrophone, a device for placing and removing an AT from the ground, means for searching for an emerging AS, made in the form of a flashing beacon, satellite navigation system Glonass type, Gonets-type low-orbit satellite communication system and active radar reflector, circuit breaker duplicated by commands from the urgency device, tightness sensor, pressure sensor, recording path consisting of a four-channel filtering and amplification unit that filters the signals from the outputs three-component geophones and a hydrophone in the frequency band of 5-200 Hz and amplification of signals for supplying them to the input of a four-channel analog-to-digital converter unit (ChATsP), output signals from which they are separately fed to the input channels of the shaper (KF), where from the signals of the hydrophone and geophones an array of a separate sample is formed with a length of sixteen-bit words fed from the output of the KF to the corresponding channels of the information storage device (NI), which is a solid-state memory of four flash cards with a capacity of 2 GB each, and the ChATsP unit consists of four 14-bit ADCs, characterized in that the device for setting up and removing the AT from the ground is made in the form of n pontoons placed in tiers forming a cross-sectional pyramid and equipped with compressed gas cylinders and corresponding inlet and outlet valves, means for searching for a pop-up ND made in the form of a flashing beacon, a Glonass-type satellite navigation system, a Gonets-type low-orbit satellite communication system and an active radar reflector are located in navigation buoy associated with the MACAS cable-hitch, in which the cable is made in the form of a sensor cable.