RU2672044C2 - Marine seismology with use of towed components below water surface - Google Patents

Abstract

FIELD: geophysics.SUBSTANCE: invention relates to the field of geophysics and can be used to conduct marine seismic operations in zones covered by ice. According to the claimed solution, marine seismic equipment for a ship, the apparatus comprises a plurality of towed components receiving seismic data, the towed components being towed by the ship in a horizontal arrangement and loaded to the first levels below the surface of the water, at least one first transceiver located on the ship, wherein at least one first transceiver emits a first signal and detects first position information of the towed components in a horizontal arrangement along the first signal, and at least one second transceiver towed from the vessel and immersed in a second level below the surface of the water, wherein at least one second transceiver radiates a second signal and detects a second information about the position of the towed components over the second signal. Seismic vessel equipment also includes a processor processing the first and second position information, and generating data on the position of the towed components in a horizontal arrangement for binding to the acquired seismic data, and the formed position data take into account the nonplanar network of towed components immersed in the first levels in the horizontal arrangement.EFFECT: increased accuracy and informativeness of the data.30 cl, 32 dwg

Description

BACKGROUND

[001] In conventional marine seismic exploration, a seismic source and a number of towed streamers towed behind the seismic survey vessel are used. These towed streamers have sensors that detect seismic energy for imaging strata under the seabed. Releasing towed streamers and springs and towing them during reconnaissance can be relatively simple operations when working in open waters with moderate disturbances or in a similar situation.

[002] In marine areas covered with ice, debris, or other obstacles, or during heavy seas, reconnaissance may become more difficult, costly, or even impossible. For example, in ice-covered waters, a seismic vessel must break through ice and cross waters filled with ice floes. The noise created by collisions with ice can make the resulting seismogram difficult to understand.

[003] In addition, floating ice floes on the surface of the water make towing the source and towed streamers more difficult and predispose to damage. For example, any system components on the surface of the water may collide with ice, get stuck and get lost. In addition, ice may build up on the surface of any cables or tow ropes departing from the vessel, even from slips. Likewise, ice being pulled under the hull and floating up behind the vessel can move these cables and cables.

[004] Some methods for performing seismic surveys in ice-covered areas known in the art are disclosed in US Pat. Nos. 5,113,376 and 5,157,636 (Bjerkoy). However, to date, the problems associated with marine seismic exploration in ice-covered and obstructed waters have not been sufficiently resolved.

[005] An object of the invention from the present disclosure is directed to eliminating or at least mitigating the negative effects of one or more of the problems set forth above.

SUMMARY

[006] In the embodiments disclosed in this application, a marine reconnaissance apparatus for a ship has towed components for acquiring seismic data. Towed components towed by a ship are submerged one level below the surface of the water.

[007] In specific embodiments of the apparatus, towed components may include a three-dimensional arrangement of seismic towed streamers and a source (s) that have neutral buoyancy for towing below the surface of the water during exploration. For example, towed components may include a float submerged below the surface of the water and supporting at least one towed component. The float has pre-configured buoyancy so that the towed component can be towed at a predetermined depth below the surface of the water. To configure buoyancy for the implementation characteristics (for example, for towing speed, depth, component weight, etc.) in the float, you can use floating inserts and gaskets with neutral buoyancy located in the cavity of the float to configure the buoyancy of the float.

[008] The towed components may include a towed streamer towed by a vessel and supported by a float. Such a towed streamer typically has one or more sensors for sensing a seismic signal. In addition, the towed component may include a braid deflector towed by the vessel and supported by the float. The braid diverter is typically connected to one or more additional towed components.

[009] In the specific embodiments disclosed in this application, a marine exploration vessel is used to tow towed components of seismic equipment on one or more cables or cables. A ship has one or more skegs mounted on a ship and extending at least below the ship's waterline. For example, the skeg can be mounted at the stern of the ship, and the distal end of the skeg can be extended below the stern to at least the keel of the ship.

[010] The skeg has one or more shuttle trolleys moving along the skeg, and each of the one or more shuttle trolleys, in turn, has one or more towing points located on the shuttle trolley and moved along with it along the skeg. At one or more tow points, one or more cables are supported for towing seismic equipment behind the vessel and below the surface of the water.

[011] To guide the shuttle carriage, the skeg may have a rail extending along the skeg, and pulleys can move the shuttle carriage along the first skeg. In addition to the shuttle trolleys, a passage is formed in the skeg that extends at least below the ship's waterline. A passage protects one or more seismic equipment cables from the vessel to a location below the waterline.

[012] In the embodiments disclosed in this application, a marine reconnaissance apparatus for a ship having towed components for acquiring seismic data uses positioning to find the relative positions of the components submerged below the surface of the water. In particular, at least one first transceiver located on the vessel emits a first signal and detects first information about the position of the towed components from the first signal. At least one second transceiver towed from the vessel is submerged a second level below the surface of the water. The second transceiver emits a second signal and detects the second position information of the towed components from the second signal. For example, this second transceiver may be located on the released device, towed behind the vessel at a greater depth than the immersion depth of the various towed components.

[013] Various devices can be used as transceivers to detect position information. For example, the transceivers may be acoustic transceivers and may emit signals, such as positioning acoustic signals, ultrashort baseline system signals, short baseline system signals, and long baseline system signals.

[014] In addition to the first and second transceivers, transverse communication equipment located along the towed streamers towed in the arrangement behind the vessel may be used in the apparatus. When seismic data is received from the towed streamers, the transverse communication equipment emits a third signal and detects third information about the position of the towed streamers from the third signal.

[015] The obtained position information may include the distances (and bearings) of the towed components relative to the transceivers. Ultimately, the processor can process the position information and can perform the operation of deriving the positions of the towed components to bind to the resulting seismic data. The resolution of these output positions may be increased since position information is obtained due to two different aspects (i.e., different immersion depths and angles of the first and second transceivers).

[016] The towed components may include a seismic source having at least one transponder responding to the first signal. In this case, at least one first transceiver located on the vessel may include one transceiver located on the vessel, and there may be a second transceiver located on the source. The ship’s transceiver paired with the seismic source transponder, while the source transceiver emits a signal for additional transponders of the towed components towed behind the source to determine their relative position.

[017] In the marine seismic survey method disclosed in this application, a vessel tows a plurality of towed components submerged one level below the surface of the water so that the towed components can receive seismic data. The first information about the position of the towed components is detected by the first signal emitted by at least the first transceiver located on the vessel. In addition, the second information about the position of the towed components is detected by the second signal emitted by at least one second transceiver towed behind the vessel and immersed at a second level below the surface of the water.

[018] When position information is detected, at least the distances (and bearings) of the towed components relative to the transceivers can be obtained. For more information, cross-link equipment can be used on towed streamers of towed components, and third information about the position of towed streamers can be detected from the lateral communication signals between towed streamers.

[019] Ultimately, the positions of the towed components can be refined by processing various pieces of position information. In turn, the specified provisions can be tied to the obtained seismic data to increase the resolution of seismic exploration.

[020] In the method disclosed in this application, a seismic arrangement is designed having an arrangement of towed components with neutral buoyancy in water when towed during a seismic survey. Towed components include at least towed streamers and scythe deflectors. The method includes determining the weight and drag when immersing the towed components and calculating the drag forces depending on the buoyancy necessary to maintain neutral buoyancy of the towed components at least one towing speed, based on the determined weight and drag of the towed components.

[021] The ability to float the seismic arrangement is configured based on the calculated drag forces depending on buoyancy. For example, configuring a seismic pop-up ability may include configuring the first floats for towed streamers and / or second floats for diverters of seismic streamers. In addition, as an option, the floating ability can be configured for a seismic source towed by seismic surveying.

[022] The balancing forces necessary to maintain a towed streamer of a seismic arrangement having a configured ability to float at least at a given depth in water are calculated depending on one or more deviating seismic acquisition variables. For example, deviating variables may include a change in the set towing speed, course change, environmental conditions, water salinity, water temperature, and sea current.

[023] The active surfaces for controlling the seismic alignment are configured based on the calculated balancing forces. For example, one or more controllable hydrofoils can be selected for installation on one or more towed streamers. The arrangement of the towed components in a seismic arrangement is designed with a configured floating ability and configured active surfaces.

[024] Since the configured floating ability can change the variables used in the analysis, it is preferred that the method includes, after configuring the floating ability, determining the drag with the configured floating ability and recalculating the drag forces based on the buoyancy necessary to maintain neutral buoyancy of towed components at least at one towing speed, based on certain weight and frontal support otivleniya towed components and a certain drag configured with the ability to float.

[025] Since the configured floatability may need to be adjusted in the field or to suit implementation features, it is preferable that the method includes configuring the floatability taking into account the adjustable buoyancy range. The adjustable buoyancy range may or may not be determined according to the tolerance, in which case the additional floating ability is configured for seismic alignment.

[026] The above summary is not intended to be a summary of each possible embodiment or every aspect of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

[027] FIG. 1A-1B are side and top views of a marine seismic survey system according to some ideas of the present disclosure;

[028] FIG. 2A-2D are views of the stern parts of a vessel having skegs according to various embodiments for towing a group of seismic towed streamers and a source from an open marine seismic survey system;

[029] FIG. 3A-3B are views of the stern of a vessel having a skeg with movable shuttle trolleys for adjusting towing points, according to another embodiment;

[030] FIG. 3C is a view of a skeg having adjacent shuttle trolleys;

[031] FIG. 3D is a view of a skeg having shuttle trolleys located one above the other;

[032] FIG. 4A is a plan view of the skeg of FIG. 3C;

[033] FIG. 4B is a detailed view of the skid pulley systems of FIG. 3C;

[034] FIG. 4C is a detailed view of the distal end of the skeg of FIG. 3C;

[035] FIG. 5A is a perspective view of the disclosed marine seismic survey system showing some additional components;

[036] FIG. 5B is a flowchart of a method for designing a three-dimensional arrangement of neutral buoyancy, such as in FIG. 5A;

[037] FIG. 6 is a view of buoyancy components for the source and one of the towed streamers towed behind the ship from the skeg in the system of FIG. 5A according to the present disclosure;

[038] FIG. 7 is a more detailed view of the buoyancy components for the source of FIG. 6;

[039] FIG. 8A-8D are a side view, an exploded view of two parts, and two cross-sectional views of a float with adjustable buoyancy from the components of buoyancy in FIG. 7;

[040] FIG. 9A is a view of a float with adjustable buoyancy for a towed streamer, such as in FIG. 7;

[041] FIG. 9B-9C are sectional views of a float with adjustable buoyancy for a towed streamer, such as in FIG. 7;

[042] FIG. 10A-10C are views of floating streamer deflectors according to the present disclosure for an open marine seismic survey system;

[043] FIG. 11A is a perspective view of a controlled stabilizer according to the present disclosure for a towed streamer from an open marine seismic survey system;

[044] FIG. 11B is a side view of a guided wing according to the present disclosure for a towed streamer from an open marine seismic survey system;

[045] FIG. 12 is a side view of positioning components according to the present disclosure for an open marine seismic system; and

[046] FIG. 13-14 are plan views of transverse communication equipment for an open marine seismic survey system.

DETAILED DESCRIPTION OF THE INVENTION

A. Marine seismic system

[047] The marine seismic survey system 10 of FIG. 1A, 1B may be used in ice-covered areas having glacial ice, pack ice, and ice floes. However, elements of the system 10 can be used in other areas with debris, floating debris, objects dropped from ships, or other obstacles or barriers on the surface of the water that may collide with towed components of the marine seismic survey system. In fact, this system 10 and others disclosed in this application can be used in any environment, and not only in which there is a tendency to the presence of obstacles or obstacles, such as ice. For example, with bad weather, large waves, noise, common hazards and even normal conditions encountered during marine seismic surveys, you can get the effect of the systems of this disclosure. Accordingly, in the present disclosure, reference to ice-covered or obstructed waters is an explanation.

[048] For example, it is preferable that in the ice-covered areas, the system 10 includes an icebreaking vessel 35 that breaks the ice in front of the towing vessel 30. In operation, the icebreaking vessel 35 destroys the pack ice and deflects the ice floes to form a passage for the towing vessel 30 . When the towing vessel 30 tows one or more towed streamers 60, a power supply 90 and a control system 40 having a seismic recorder in which seismic data obtained for tchikami 70 to 60 towed streamers.

[049] When the towing vessel 30 is operating in ice-covered or obstructed waters, or even when the towing vessel 30 is operating under normal conditions in ordinary waters, the guard 50 on the towing vessel 30 is connected to towing cables 62 and connected to towing cables - cables 65 and with life support cables 95 that support towed streamers 60 and sources 90. (Although numerous towed streamers 60 are shown, system 10 may have one towed streamer 60 if desired). As discussed below, a protective device 50 (referred to in this application as a skeg) holds towing cables and cables for towed components away from the surface of the water, which in ice-covered areas may have, for example, ice floes, other obstructions or the like in others areas. Skeg 50 allows the vessel 30 to tow towed streamers 60 and at the same time cope with the problem of various loads created by the movements of the vessel 30, forces from towed objects and interactions with possible ice, waves or other obstacles.

[050] In general, skeg 50 can be positioned on ship 30 anywhere. However, as best shown in FIG. 1A, it is preferred that skeg 50 extends from the stern of the hull in the stern. This aft location is better suited for manufactured cables, tow cables, and other components of the marine seismic system towed by the vessel 30. In one arrangement, the skeg 50 is a fixed addition to the vessel 30, which can be welded, attached or otherwise attached to an existing shipyard hull structure. Otherwise, the vessel 30 can be designed and built in advance with a suitable skeg 50 included in the hull structure, or the skeg 50 can be a component that is equipped with appropriate mechanisms for placing and holding it on the ship 30. In another arrangement, the skeg 50 can be removable or an independent component that can be temporarily installed on board the vessel without the need to change the hull.

[051] Skeg 50, extending below the waterline of the vessel, holds the attachment points of towing cables (eg, 62), towing cables-cables 65, cables 95 life support 95, etc. below the surface of the water. It holds tow ropes 62 and cables 65, 95 below the surface of the water and at a distance from any objects (for example, any floating ice floes floating on the surface of the water that could interfere with tow ropes 62, tow ropes 65, life support cables 95, etc. .d. or gather near them). The tow cables 65 connected to the seismic recorder of the control system 40 are extended from the vessel 30, and the skeg 50 guides these tow cables 65 towed streamers below the surface of the water (for example, so that the ice does not interact with them or collect near them). For ice-covered or obstructed areas, the depth required to effectively hold tow tow cables 65 towed streamers and attached towed streamers 60 below any ice level may depend on the particular implementation. As one example, skeg 50 may extend a distance of approximately 7 m below the waterline of vessel 30. However, depending on the ice regime under which the vessel operates, the size of the vessel, and other factors, this distance can be changed for a particular implementation.

[052] In the present arrangement, the seismic source 90 is suspended horizontally in the water column behind the vessel 30 and has a plurality of seismic source elements 91, which are usually air guns. (Although one source 90 is shown, multiple sources may be used in system 10). A power supply or life support cable 95 connected to the power supply system 45 is extended from the vessel 30, and in addition, the skeg 50 directs this life support cable 95 below the surface of the water, so that it is away from ice, obstacles, waves, wind waves and etc. A tow rope (not shown) may connect the life support cable 95 to the skeg 50 to facilitate towing of the source 90 behind the vessel 30.

[053] Preferably, the life support cable 95 has neutral buoyancy, and the source 90 can be stabilized by one or more buoyancy devices or buoys 94. Since ice moves over the surface of the water in ice-covered areas, the buoyancy device 94 can be designed to solve the problem of collisions with ice that occurs when it floats on the surface. According to this buoyancy device 94, a certain shape can be shaped to minimize collisions with ice or other obstacles, and it can be positioned horizontally to overcome any floating ice or obstacles on the surface. However, as discussed in more detail below, it is preferable that when swimming below the surface, the device 94 buoyancy was designed to exclude contact with ice or other obstacles.

[054] To tow a horizontal source 90 behind the vessel 30, a tow rope (not shown) may be used attached to the skeg 50 underwater and connected to a source 90 suspended below the surface of the water. One or more supporting cables connect the buoyancy device 94 to the source 90. During operation, the life support cable 95 is extended from the end of the vessel 30, passed through the channel in the skeg 50 and connected to the source 90.

[055] In general, tow cables 62, towed streamers 60, sensors 70, cables 65/95, control system 40, and power supply system 45 may be common components known and used in marine seismic surveys. For example, source elements 91 may operate in any conventional manner to generate a suitable seismic source signal. In addition, neutral buoyancy cables used to support the respective marine seismic sensors 70 can be used for towed streamers 60. Essentially, each towed streamer 60 can have several sections, each with an external coating to protect the inside from water and has axial elements located along the length to give axial strength. In addition, each section of the towed braid 60 may have a wiring harness through which energy is transmitted, and wires for data transmission. As part of the sections, the sensors 70 are typically hydrophones located in the towed streamer 60.

[056] As also shown in FIG. 1B, braid deflectors, stabilizers or dampers 64 and wiring cables 68 can be used to support multiple towed braids 60 in a three-dimensional arrangement 20 behind the towing vessel 30. In addition, these braid deflectors 64 and wiring cables 68 can be similar to conventional components used in marine applications. a seismic survey, with the exception that the braid diverters 64 are preferably towed below the surface of the water, as discussed below. Finally, towed streamers 60 may include control devices 80 located on them, that is, along their length and / or at their distal ends. These control devices 80 may include tail buoys, nacelles, vanes, steerable apparatuses and the like, disclosed in this application and incorporated by reference in patent applications.

[057] Since the towing vessel 30 tows the seismic arrangement 20 in ice-covered or obstructed waters, it is preferable to take into account possible problems associated with floating ice floes and the like when discharging seismic components, which may interfere with the release and selection of towed streamers 60 and sources 90. The release and selection of the system can be performed when the towing vessel 30 is at a distance from heavy ice. For example, a seismic system can be normally discharged before placing cables in skeg 50 and dipping various components.

[058] In a typical implementation, towed streamers 60 may be several kilometers long, and a significant portion of the seismic system may need to be deployed to the scaffold, which may not always be in ice-covered areas. Therefore, it is desirable to be able to release / select the disclosed seismic systems in other parts of the ice-covered area, including those with ice.

[059] When propelled, vessel 30 can break ice and / or move ice floes to the side, so that a narrow outlet will be in its wake stream, where ice may be almost absent. Of course, this depends on how tight the ice is and how it can be passed. When conditions permit, it is preferable to be able to release and select seismic streamers 60 from a group in such clean areas. Therefore, when prospecting in ice-covered waters in such release and selection methods, it is preferable to use such a potentially clean area. In the examples below, several types of seismic groups are considered that can be produced and selected at such a site.

[060] In FIG. 1B, in the seismic group or arrangement 20 towing cables and towing cables-cables of 65 towed streamers were used, providing connection from skeg 50 on the vessel 30 to the head floats 350. Wiring cables 68 were connected across the head floats 350, and the towing cables 62 were released together with the deflectors 64 braids at one end.

[061] Although in the arrangement of FIG. 1B shows one skeg 50, for the vessel 30, multiple skegs 50 can be used on the vessel 30 to release towed streamers 60. Using multiple skegs 50 can facilitate the release and selection of towed streamers 60 by disassembling them in the layout. Although in the arrangements of FIG. 1A, 1B and elsewhere, one source is shown; multiple sources may be used. In addition, one source can be towed in the usual place behind the vessel 30, while another source can be towed behind the extended group of towed streamers 60. This second source can be used to obtain countdowns from the towed streamers 60, which may be preferable for data recording and analysis. .

[062] In order to better record and display the obtained seismic data, during marine seismic, it is desirable to determine, track the positions of the towed streamers 60 and source 90, and possibly control them. Positioning can be done using Global Positioning System (GPS) samples for towed streamers 60 during reconnaissance. This can be done in some cases, but in other cases, obtaining GPS readings for the locations of towed streamers 60 may not be possible.

[063] For example, in marine seismic systems 10 according to the present disclosure, obtaining GPS readings can be difficult because the system 10 is immersed well below the surface of the water, so that global positioning system receivers (GPS receivers) cannot perform readout operations . Several types of manufactured or controlled devices 80 can be used on towed streamers to obtain GPS readings or to control the positions of towed streamers 60 during reconnaissance. In addition, these methods are disclosed in incorporated by reference patent applications. According to other methods, seismic exploration can be carried out in an open course without obtaining GPS readings for towed streamers 60. These methods are also disclosed in incorporated by reference applications. Details relating to both of these methods are not repeated in this application for the sake of brevity.

[064] Given the understanding of the disclosed system 10, now consideration will be given to specific components of the system, starting with the skeg.

B. Skeg Designs

[065] As discussed above, skeg 50 is used on towing vessel 30 to hold tow cables 62 and cables 65/95 below the surface of the water (for example, at a distance from ice floes or the like). As shown in FIG. 2A, skeg 100 according to one embodiment is installed in the aft or aft 32 of the seismic towing vessel 30 used to tow seismic towed streamers (not shown). As noted previously, skeg 100 can be mounted on ship 30 anywhere, including the port side, starboard side, bow or shaft for lowering and lifting equipment in the hull. However, the stern or feed 32 of the vessel 30 is preferable, since towed streamers (not shown) are best towed behind the vessel 30, and this may contribute to avoiding waves, ice floes or the like when towing towed streamers.

[066] In this embodiment, the skeg 100 is a single conduit extending from the stern 32 of the vessel 30. In order not to substantially interfere with the control of the vessel and other functions, it is preferable to use this skew 100 as a single conduit on the vessel 30 having two propellers 36, although it can be used on ships of other types. Skeg 100 extends below the hull between the slips 34 used to release and select the towed braids and cables. Throughout the aft or rear, in skeg 100, an open passage or channel 120 is formed for passing cables of towed streamers, source cables, and running ends, discussed below.

[067] Even though skeg 100 extends from aft 32, when explored in ice-covered waters, ice can be drawn into the stream along the bottom of the hull. This retractable ice ultimately reaches the stern 32 of the vessel 30, where it again emerges. In other situations, ice colliding with the bow of the vessel 30 may be pulled under the hull of the vessel and then attempt to surface near the stern 32 as the vessel 30 moves forward. In any case, skeg 100 acts as a protective conduit, holding tow cables, cables, etc. in the distance from this ice.

[068] At its distal end, skeg 100 may have a base or plate 110 on which attachment points 114 / 116a-b are provided for tow cables. Thus, towing points 114 / 116a-b are provided on skeg 100 below the surface of the water (and at a distance from the ice floes on the surface). Furthermore, in addition to the rest of the protection, these towing towing points 114 / 116a-b below the surface contribute to maintaining the towed streamers and the source below the surface.

[069] In the skeleton 100 already described, one conduit is provided directed downward from the center of the stern 32 of the vessel, which may be best suited for the vessel 30 with two propellers 36. Alternatively, the skeg 100 of FIG. 2B is formed by two or more conduits or passages 120 directed downward from the stern 32 of the vessel, and can be used on a vessel 30 having one or more propellers 36 and one or two rudders 37.

[070] Two channels 120A-B extend from the stern 32 of the vessel 30 and beneath the surface of the water on each side of the propeller 36 of the vessel. Thus, the wake from the propeller 36 and the rudder 37 of the vessel 30 may remain relatively uncovered in the open space between the channels 120A-B.

[071] The base plate 110 at the front end is connected to the keel of the vessel 30. As in previous designs, the base plate 110 has tow points for attaching tow cables used to support towed streamers and the source of the seismic system. For example, these tow points can be located along the rear edge of the plate 110. In addition to this, cable attachment points in the channels 120A-B are also provided on the rear edge of the plate 110.

[072] In the previous examples, the skeg had tow points that were fixed. Alternatively, in FIG. 2C, 2D show the layout of a skeg 100 having adjustable tow points for attaching tow cables. In FIG. 2C, the skeg base 110 has grooves or connection points 115 that allow you to adjust the position or automatically adjust the horizontal position on the base 110 of the connecting elements 67 at one end of the tow cables 62. In FIG. The 2D skeg base 110 has grooves or connection points 117 on stabilizers or turrets 119 that allow you to adjust the position or automatically adjust the vertical position based on 110 of the connecting elements 67 at the end of the tow cables.

[073] As shown, when automatically adjusting the position of the grooves or places 115 and 117, the connections can provide free movement of the connecting elements 67. The actual position of the tow cables 62 can be adjusted elsewhere in the system using any of the various devices disclosed in this application. Instead of extended grooves or connection points 115 and 117, you can have a number of pre-configured preset positions for pre-adjusting the tow ropes 62. In addition, adjusting the positions of both the vertical and horizontal towing points on the skeg 100 can be achieved by a combination of elements from both figures FIG. 2C, 2D. Essentially, a vertical stabilizer or turret 119 with a vertical groove or junction 117 can be moved or fixed in a horizontal groove or junction 115 of the base 110. In addition, when combining the elements of the tow point for tow ropes 62, it can be adjusted both vertically and horizontally.

[074] FIG. 3A-3B show another vessel 30 according to the present disclosure having one or more skegs 100 extending, as before, from its stern. In this case, two skegs are shown (one on the port side and the other on the port side), but more or less can be used. These skegs 100 also have adjustable tow points.

[075] Each skeg 100 includes a conduit 120 for passing tow cables-towed braids and source cables (not shown). Each of the skegs 100 has one or more shuttle trolleys or elevators 140A-B moving along or along these conduits 120, which may have one or more towing points 142. One or more shuttle bogies 140A-B can move to the top and bottom of conduit 120 when using pulley systems 150A-B to raise and lower the shuttle bogies 140A-B and their tow points 142.

[076] As previously noted, skegs 100 protect seismic equipment by moving it below the surface of the water (for example, when there is ice on it). In addition, the skegs 100 assist in moving the towing points 142 of the seismic arrangement (20) to a predetermined depth at or below the keel of the ship. Shuttle bogies 140A-B can provide additional stability to the arrangement (20) of the seismic system and can provide towing points 142 for towed streamers, sources, and other cables at or near a predetermined depth of the system below the surface of the water.

[077] In FIG. 3A, 3B, each of the skegs 100 has two shuttle trolleys 140A-B that can independently move up and down rails 130 located on conduits 120. Each shuttle trolley 140A-B has one or more towing points 142, which may include openings, blocks or other connectors for connecting tow cables (not shown), etc. seismic system, produced, towed and selected from the vessel 30.

[078] For illustration, the shuttle carts 140A-B are shown in two extreme positions, one upper position near the deck of the vessel and the other lower position near the base 110 of the skeg. In fact, each skeg 100 may have only one set of shuttle trolleys 140A-B, which can be moved by these pulley systems 150A-B between these upper and lower positions. However, in other arrangements, each pulley system 150A-B can be used to move multiple sets of shuttle carts 140 or more shuttle carts 140 along rails 130.

[079] In FIG. 3C, skeg 100 is shown with shuttle trolleys 140A-B located side by side so that they can be moved relative to each other using adjacent pulley systems 150A-B. In FIG. The 3D shuttle trolleys 140A-B are arranged sequentially on the skeg 100 and can be moved relative to each other using the internal and external pulley systems 150A-B.

[080] The shuttle trolleys 140A-B on the skegs 100 of FIG. 3A-3D allow operators to haul towed streamers and springs separately and / or independently. To return the lower, sequentially shuttle car 140A and select the tow cables connected to it from FIG. 3D requires the simultaneous return to the previous position of another sequentially shuttle car 140B, even though the shuttle car 140A-B can be moved separately. The commissioning of these shuttle bogies 140A-B of FIG. 3D can be sequential or simultaneous. In contrast, the adjacent shuttle trolleys 140A-B of FIG. 3C can be moved separately and can be put into operation and returned independently, and in the field this can provide a number of advantages.

[081] Referring to FIG. 4A-4C, which disclose further details regarding skeg 100, such as in FIG. 3C. In FIG. 4A shows a top view of a skeg 100 having adjacent shuttle trolleys 140A-B, in FIG. 4B shows a detailed view of the pulley systems 150A-B and in FIG. 4C shows a detailed view of the end of skeg 100. Although these details are provided for skeg 100 such as in FIG. 3C, similar details relate to skeg 100 of FIG. 3D

[082] Each shuttle trolley 140A-B is moved by its respective pulley system 150A-B, and shuttle trolleys 140A-B are moved along the passage 122 of the conduit, which is separated from the rail track of the shuttle trolleys by a partition or wall 124. One shuttle trolley 140A can be larger than the other shuttle trolley 140B, and may have additional towing points 142, although other configurations may be used. For example, an internal shuttle car 140B mounted on the inside of the skeg 100 may be used to tow sources. An external shuttle car 140A mounted on the outside of the skeg 100 may be used to tow towed streamers and scythe deflectors. For tow cables of scythe deflectors and other outboard tow cables at tow point 142, the swivel and pulley assembly 144 may be used.

[083] As shown in FIG. 4B, 4C, in the pulley systems 150A-B, the upper and lower rollers and steel cables are used. For the upper rollers, electric motors (not shown) can be used to move the cables and shuttle carts 140A-B. To facilitate the movement of the shuttle bogies 140A-B along the rails 130, the lower friction bars 132 formed of nylon or the like can be mounted on both sides of the shuttle bogie 140A-B.

[084] When the shuttle bogies 140A-B are raised and lowered or stopped in place on the skeg 100, the edges of the rails 130 hold the shuttle bogies 140A-B and keep the seismic system tow ropes horizontal behind the vessel 30. If necessary, additional stop or brake elements can be used for vertical locking of the shuttle trolleys 140A-B on the rails 130. In addition, during operation by locking the pulley systems 150A-B, it is possible to hold the shuttle trolleys 140A-B vertically.

C. Three-dimensional seismic system towed below the surface

[085] In FIG. 5A shows a perspective view of additional components of the disclosed seismic system 10 according to the present disclosure. System 10 includes one or more skegs 100 at the stern of the vessel 30. During reconnaissance, one or more skegs 100 tow an arrangement or group 20 of multiple towed streamers 60 and tow one or more sources 200 behind ship 30. Skeg 100 holds cables and tow cables for these seismic components below the surface of the water so that system 10 can be used for seismic exploration in ice-covered areas, waters with turbulent flows or the like. As noted above, skeg 100 can have independently moving shuttle trolleys and tow points so that operators can separately release and select towed streamers 60 and springs 200.

[086] As noted in this application, when using the system 10 in areas where ice accumulates on the surface, or in stormy weather, when towing below wave action can improve recording, the components of arrangement 20 are towed below the surface of the water. To do this, for towed streamers 60, springs 200, and scythe deflectors 400, for all of them, buoyancy devices are used to maintain them at a predetermined level below the surface of the water.

[087] One or more sources 200, in which groups of air guns or the like can be used, are released behind the vessel 30 and usually before the arrangement 20. The sources 200 are towed using cables 204 and tow cables (not shown) from skeg 100, which pulling 200 springs below the surface of the water. One or more of the sources 200 is separated from the arrangement of 20 towed streamers and have buoyancy devices described in more detail below. In addition, when using methods such as those disclosed in incorporated by reference patent applications, sources 200 can be actively managed.

[088] The towed streamers 60 are released to form the arrangement 20 using tow cables 65 (and optional tow cables (not shown)) extending from the skeg (s) 100 below the surface of the water. Tow ropes 62 and guide slings 63 are connected to the braid deflectors 400, and drop cables 66 connect the braid deflectors 400 to the wiring cables 68, which extend from the edge to the edge of the towed braids 60 near the head floats 350. During operation, the braid deflectors 400 hold the outer edges of the towed braids 60, expanded in an arrangement of 20.

[089] The towed braids 60 include head floats 350 at the front end of the towed braids 60. The head floats 350 are integrated to reduce towing cable cables 65 towed braids 60 and wiring cables 68 to the neutral concentrated load. Continuing beyond the head floats 350, each towed streamer 60 has a number of seismic sensors 70, a control device 80, and other positioning and measurement equipment, discussed below. In addition, if necessary, additional floats 350 can be used at various places in the towed streamer 60.

[090] As an option for using the head floats 350, buoyancy can be distributed along the tow cable 65 in the form of a floating vibration isolation module or a floating coating applied externally. The buoyancy force at any of these objects can be either static or active.

[091] The braid diverters 400 are formed with neutral buoyancy or have buoyancy devices 406 described below. As tow ropes 62 for braid deflectors 400, it is preferable to use ropes that have substantially neutral buoyancy. For example, the tow cables 62 of the braid deflectors can be high elastic modulus polyethylene (PML) cables or other material.

[092] Since the system 10 is towed below the surface of the water, various physical factors such as drag, buoyancy, weight, and other factors influence the immersion depth and behavior of the system 10 underwater. In this regard, hydrodynamic modeling of the required system 10 is performed in order to understand the relationships between the towing forces and drag, buoyancy and weight and other factors for each component of the system 10 and how they work together. Some components of system 10 are designed with neutral buoyancy, while other components are designed to compensate for the weight of additional conventional equipment. Each of the components of buoyancy is preferably formed from syntactic or other incompressible foam, so that when the system is controlled, buoyancy remains relatively constant depending on the depth.

[093] FIG. 5B, a flowchart illustrates a method 300 for designing a three-dimensional arrangement of a neutral buoyancy system, which includes the steps of modeling and making decisions that need to be made when configuring the arrangement. For illustrative purposes, calls may be made to the system 10 of FIG. 5A, but method 300 can be applied to any configuration. In fact, the configuration of the towed seismic equipment, for example, the specified size of the three-dimensional arrangement 20, the number of towed streamers 60, the number of receivers 70, the number of sources 200, the length of towed streamers 60, etc., and the specific types of equipment used are mainly determined by the implementation and intended use seismic system 10. As should be understood by a person skilled in the art, these and similar considerations will form part of the disclosed method 300, but in this application they are not de aliziruyutsya.

[094] Having the correct understanding of the towed components for the specific configuration of the desired arrangement 20, the operators measure or evaluate (block 302) the dive weight of all the towed seismic components of the arrangement 20 and measure or evaluate the immersion drag (block 304) for all towed arrangement components 20 at one or more (and preferably different) tow speeds. The towing speeds of interest are the expected or planned towing speeds of the seismic vessel 30 when passing observation lines during reconnaissance. Determination of weight and drag when diving towed components may or may not include results for floats already included in some components.

[095] Using a hydrodynamic modeling method, such as that available in the software, operators model the hydrodynamic forces of the desired arrangement 20 and calculate (block 306) the drag forces depending on buoyancy, necessary to maintain neutral buoyancy of all towed components at one or more specified speeds in water. For example, when designing a system 10, numerical hydrodynamic analysis is performed relative to the required three-dimensional arrangement of 20 towed braids in order to understand the forces acting on all the components of the immersed towed components. One specific software product or hydrodynamic modeling algorithm that can be used in these calculations includes OrcaFlex, supplied by Orcina Ltd. from the UK, although other products can be used. Floating components (source floats, head floats 350, 406 braid deflector floats, etc.) attached to sources 200, towing cable cables, 400 braid deflectors, etc. or used on them may be part of this simulation.

[096] After the simulation has been performed, on the basis of the hydrodynamic forces and the calculated forces, depending on the buoyancy, the operators configure (block 308) the degree of floating ability, which must be added to the arrangement 20 to maintain neutral buoyancy of all towed components. Configuring the floatability includes embedding additional syntactic floats for the towed components and / or incorporating distributed component buoyancy into the arrangement 20. Syntactic floats and / or included distributed component buoyancy is configured for placement 20 to compensate for the influence of the weights of the towed components and towing effort. Since it may be necessary to adjust the placement of 20 in the field or to suit a particular implementation, it is preferable that the configured floating ability allows for buoyancy that is adjustable to account for variability in component weights and towing forces for a given size and geometry of the arrangement 20.

[097] For example, the floating components (that is, floats) for the arrangement 20 are configured to satisfy the buoyancy requirements at each attachment point to neutralize the weights of the system components and the forces on them. So that adjustments can be made in the field, when configuring these floating components, it is preferable to make their buoyancy adjustable within a few percent of the norm obtained by modeling. As noted earlier, it is preferable that the buoyancy devices used for the floating components are of a syntactic type, as a result of which at different depths of immersion the buoyancy inherent in the components will not change due to changes in hydrostatic pressures. In addition, this extends the range of working depths at which the arrangement of 20 towed streamers can work with deep towing.

[098] After that, having the configured floats for the arrangement 20, the operators measure or evaluate the drag of all the floats (block 310) and re-perform (block 312) a hydrodynamic simulation of the three-dimensional arrangement 20 based on the results of the drag measurement. This is done for the reason that the configured floating ability can change the dynamics of the arrangement 20 so much that the variables will need to be reevaluated.

[099] As noted above, it is preferable that the buoyancy of the added and distributed buoyancy devices can be adjusted to take into account the variability of the weights and the towing forces of the components. Therefore, at this stage, a quantitative assessment can be made to determine whether the buoyancy control sufficient in the floats is sufficient so that, if necessary, adjustment could be made in the field (decision 314). If the predetermined range of adjustable buoyancy is not provided for buoyancy of the floats, in method 300 they return to the previous steps by embedding and distributing (added 308) the added buoyancy for the weights and towing forces of the towed components to increase the overall controllability of the buoyancy of the arrangement. Preferably, the controlled buoyancy that the arrangement will have could depend on the particular implementation and a number of factors. In the general case, it is preferable that each of the various floats has an adjustable buoyancy of the order of ± 100 kg (200 kg total), so that the final buoyancy is within ± 25 kg (50 kg total). In this case, several nacelles can be used to compensate for ± 25 kg of balancing deviation.

[100] In the event that sufficient buoyancy adjustability is already configured in the floating ability of the arrangement 20, the layout of the towed components in the seismic arrangement can be configured with the configured floating ability (that is, with floats) for specific towed components, concentrated loads, etc. . so that the arrangement 20 can be towed and remain neutrally floating during operations.

[101] As can be expected, operating parameters and conditions may vary during exploration, and it is preferable to calculate and design the arrangement 20 in accordance with such changes. To do this, after configuring the ability to ascend with a given adjustability (decision 314), the operators model (block 316) the balancing forces that are necessary to maintain the towed streamers 60 at the required depth due to deviations from the specified target towing speed, course changes, and sea currents surrounding conditions, salinity, water temperature, etc. And in this case, the hydrodynamic modeling can be performed using the hydrodynamic modeling software with input data for the obtained 3D modeling of the arrangement 20, as well as with variables such as expected variations in towing speed, estimated changes in course, expected sea currents and other such parameters and conditions. For example, hydrodynamic modeling can be performed within the range of expected towing speeds (for example, 2-6 knots (3,704-11,112 km / h) in order to understand the dependence of the variable drag on the concentrated loads for the specific components used.

[102] The calculated balancing forces are the correction forces that must be created by the components of the arrangement 20 to account for deviations of various variables during operations, so that the arrangement 20 can be towed and, if desired, maintained at the depth of exploration. Based on the calculated balancing forces, the operators determine (block 318) the size and number of active surfaces 80 to be added to the arrangement 20 to obtain the proper balancing forces to compensate for the expected variability. These active surfaces 80 may include control devices, hydrofoils, and the like disclosed in this application. Such active surfaces 80 are preferably added to the head of the arrangement 20 at the front ends of the towed streamers 60, and they can simplify the regulation and operation of the system 10, although other locations can be used for the active surfaces 80. (Depending on the circumstances, it may be necessary to measure or evaluate the drag of all active surfaces 80 and repeat the hydrodynamic modeling of a three-dimensional arrangement based on the results of the drag measurement).

[103] Active surfaces 80 can be used to compensate for expected variations in speed and other variables. Some active surfaces 80 may be standard cable gondolas or may be modified active devices with larger wing surfaces and an applied force depending on the level of expected variability. Depending on the expected level of depth variability, several of these active surfaces 80 are preferably located near the head floats 350 of the towed streamers (i.e., in the tension section).

[104] In conclusion, the seismic arrangement 20 is formed with the arrangement of floating components (for example, source floats, head floats 350, streamer diverters 406, etc.) and active surfaces 80. After formation, the entire arrangement of 20 towed streamers can be towed completely submerged without the need for orienting means on the surface. In the case of release of the arrangement 20 with an acceptable range of adjustable buoyancy, the active surfaces 80 can be further adjusted to any fluctuations in speed, course, environmental conditions, water salinity, water temperature, sea current, etc.

D. Management of buoyancy

[105] In order to control the buoyancy of system 10, a buoyancy system shown and discussed with reference to FIG. 6, 7 and 8A-8D. For towed streamers 60, a buoyancy system shown and discussed with reference to FIG. 6 and 9A, 9B. For scythe deflectors 400, the buoyancy system shown and discussed with reference to FIG. 10A, 10B. Finally, for towed streamers 60, control devices shown and described with reference to FIG. 11A, 11B.

1. Source floats

[106] First, we turn to controlling the buoyancy of the source 200. In FIG. 6 shows a portion of a vessel 30 with a skeg 100 having a shuttle car 140 according to the present disclosure. In this side view, the skeg 100 shows a towing source 200 and a towed streamer 60 of a three-dimensional arrangement (20 in FIG. 5A).

[107] A buoyancy system is used for the source 200 to support the source component 210, towed by the vessel 30 on the life support cable 204 from the skeg 100. The source component 210 may be a seismic source, an air gun, an electromagnetic source, a magnetic source, a sonar device, a sound generation device or image building or other towed component. Other sources 200 can also be used in system 10.

[108] The buoyancy system of source 200 uses a number of floats or buoys 220 and 250 connected to each other. At least one of the floats 220 is controllable in depth, and this means that the buoyancy of float 220 is actively controllable. For example, this float 220 may have a depth of immersion in the water column, automatically adjustable on the float 220 and / or operatively adjusted from the control unit 40 on the vessel. User interface screens for monitoring the depth-controlled float 220 may be accessible on a monitor connected to the ship control unit 40. Thus, operators on board vessel 30 can use screens to monitor the operation of the depth-controlled float 220 and read measured parameters, such as depth of immersion, air pressure, humidity, temperature, etc. In addition, during operation, the operators on the vessel 30 can adjust the operating parameters of the float 220, for example, change the controlled depth of immersion. This can be especially useful when making changes to seismic work or when submerging source 200 to a greater depth in the water column to avoid surface obstructions.

[109] One or more additional floats or buoys 250 of the source buoyancy system have adjustable buoyancy and are tied to a depth-controlled float 220. These buoyancy controlled floats 250 have buoyancy obtained by modeling and pre-configured before being placed in a particular implementation. For example, the buoyancy of each of these floats 250 is configured for towed components or portions of towed components, and each float 250 in its place in system 10 is used to maintain the expected values of towing speed, drag, etc.

[110] As shown, at least one depth-controlled float 220 is preferably in line with one or more additional floats 250 tied behind and intended to follow the first float 220. Preferably, connections 226 between each of the floats 220 and 250 were flexible and allowed different floats 220 and 250 to move relative to each other.

[111] Other configurations may be used. For example, as shown in FIG. 6, another depth-controlled float 220 can be positioned at the end of the set of adjustable floats 250. Accordingly, the buoyancy system of the source 200 can have one or more depth-controlled floats 220 and one or more adjustable floats 250 in any given arrangement.

[112] One or more lines 209 from the supply cable 204 are connected to one or more depth-controlled floats 220. The working fluid from the source 45 of the working fluid on the vessel 30 is transmitted through the supply cable 204 and lines 209 to the floats for 220 to fill internal volumes. Preferably, the working fluid is compressed air, but other gases may be used. In addition, the working fluid may be lighter than water. Nevertheless, liquid should not be released into the marine environment unless it is safe to do so. Therefore, in some arrangements, a return line (not shown) from the floats 220 may extend back to source 45 on the vessel 30.

[113] In fact, each of one or more floats 220 has a controller (not shown) that controls the working fluid (air) contained in the floats 220 and controls the buoyancy of the floats in the water column. Thus, the floats 220 can be maintained at a given level and, if necessary, can be transferred to other levels. This allows not only the floats 220 not to be exposed to obstacles on the surface or waves, if any, but the floats 220 can support the towed components 210 at an appropriate depth at which data recording discussed in this application can be simplified. In addition, when towing, the floats 220 can divert the towed source component 210 to a greater depth to avoid any obstacles on the surface of the water, such as ridged ice ridges and the like.

[114] Now referring to FIG. 7, which shows in more detail an embodiment of the buoyancy system of source 200 of FIG. 6. As noted above, the system has one or more depth-controlled floats 220 and one or more adjustable floats 250 tied to each other by tethered cables 226. As before, the system can be towed behind the vessel (not shown) on the life support cable 204, connected to the skeg of the vessel (not shown), and the system can be used to maintain the towed component and can be connected via a supply line 205 to a source of 45 working fluid on the vessel 30.

[115] In this embodiment, the towed source component 210 is a group of air guns 212 towed in water and connected by a life support cable 204 and an air supply line 205 to a compressed air source 45 on a ship (not shown). In the presented example, each of these floats 250 may have buoyancy pre-configured to balance the weight in water of the corresponding air gun 252, which the float 250 supports in the group of air guns 212.

[116] A depth-controlled float 220 is connected to the life support cable 204 by a tethered cable 222, and each float 220 and 250 supports portions of a group of 210 air guns using tethered cables 216. A branch line 209 from the air supply line 204 is connected to a depth-controlled by the float 220, and it supplies compressed air necessary to control the depth D _{F of the} immersion of the floats 220 and 250, and therefore the depth D _{S of the} immersion of the source component 210 during operation, described in detail below. Specific details of the depth-controlled float 220 of the system are disclosed in incorporated by reference patent applications and are not repeated in this application.

[117] FIG. 8A-8D show a side view, an exploded view of two parts, and two cross-sectional views of an adjustable float 250 of the system of FIG. 7. The adjustable float 250 includes end caps 260A-B and the main body 270. The slings 254 made of metal are located on the main body 270. The adjustable float 250 slings 254 can be solid as shown and may have rubber connected with an internal surface.

[118] End caps 260A-B are attached to the ends of main body 270 using tie rods 252 that extend around the periphery of main body 270 and attach end caps 260A-B to each end of main body 270.

[119] Each end cap 260A-B has an outer shell 262 filled with foam 264 or other floating material. Central tie rods 266 with ears at the ends for connection with safety ropes are located on the end caps 260A-B and are connected to metal plates 263 on the inner surface of the end caps 260A-B, which are supported on the main part 270. Preferably, the tie rod 266 has a welded an element 268 for facilitating the bonding of foam 264 in the end cap 260A-B with a tie rod 266.

[120] It is preferable that the end caps 260A-B externally have protective wear-resistant plates in places where the ears of the tie rods 266 extend from the end caps 260A-B. The float 250 is connected to other floats using towing ears at the ends of the tie rods 266, and the predetermined device to be supported by the float 250 (for example, one of the air guns) is connected to the mounting loops on the slings 254. The lifting rings on the slings 254 are used to lift the float during installation, etc.

[121] The main body 270 has an outer shell 272 surrounding the floating material 274, which may be foam with an apparent density of 29 lb / ft ³ (0.046 g / cm ³ ). Instead of the air reservoir, the main body 270 has a hollow core 276 in which a plurality of buoyancy elements 280 and / or gaskets 290 are held. Each of the buoyancy elements 280 has a foam insert surrounded by a reinforcing rim. Foam insert 282 may be formed of foam with an apparent density of 29 lb / ft ³ (0.046 g / cm ³ ), and rim 284 may be a plastic material part. Gaskets 290 do not have foam and instead are simply neutral buoyancy rings that can be made, for example, from pipe sections of high density polyethylene with an outer diameter of 18 inches (45.72 cm) and 7.75 inches long (19.685 cm) )

[122] The buoyancy generated by the float 250 when placed in water can be adjusted or adjusted using the buoyancy elements 280 and gaskets 290. For example, one of the end caps 260A-B (or both) can be removed from the main body 270 and the hollow core parts 270 can be filled in the required ratio with buoyancy elements 280 and gaskets 290. If minimum buoyancy is desired, the hollow core of the main part can be left empty. Increased buoyancy can be obtained by adding buoyancy elements 280 and filling any remaining space with neutral spacers 290. For full buoyancy, the hollow core of main body 270 can be completely filled with buoyancy elements 280.

[123] For example, the hollow core 276 may have space for seven elements. Maximum buoyancy can be 670 pounds (303.9 kg) when all spaces are filled with buoyancy elements 280. It corresponds to a maximum air weight of about 1,030 pounds (467.2 kg). In this case, the intermediate buoyancy values for the float 250 can range from about 630 pounds (285.76 kg) (six buoyancy elements 280 and one gasket 290) to about 425 pounds (192.77 kg) (one buoyancy element and six gaskets 290) with intermediate values between them. Minimum buoyancy can be 389 pounds (176.4 kg) when the hollow core 276 is empty. It should be understood that the configuration of the internal spaces discussed above is assumed to be approximate and may be different for a specific implementation.

[124] The buoyancy of each of the adjustable floats 250 of FIG. 7 is configured for a specific air gun or part of a group of sources, to maintain which a float 250 is placed. The gun is weighed in water or its weight in water is calculated. The buoyancy of the float 250 is then configured to balance the weight in the water of the supported gun.

2. Head floats

[125] In FIG. 6, the head float 350 supports a towed streamer 60 towed by a vessel 30 on a tow cable from the skeg 100. Other towed streamers 60 in arrangement can similarly be placed in a plane near the towed streamer 60 shown using wiring cables and braid deflectors (not shown).

[126] The head float 350 may be similar to additional floats or buoys 250 from the source buoyancy system, so that the head float 350 for the towed streamer 60 may also have adjustable buoyancy. The head float 350 is tied to tow cable 65 from skeg 100. As shown in FIG. 9A, it is preferable that the head float 350 is located directly above the towing cable-cable 65 and brackets 352, 354 and cables 356 could be used for it. In another arrangement depicted in FIG. 9C, the head float 350 may be located directly on the tow cable 65.

[127] As shown in FIG. 9A, the head float 350 has a main body 370 with an assembly of 352 brackets located thereon, which is connected by cables 356 to the brackets on the tow cable 65. The end caps 360A-B are mounted on the main part 370, and the rear end cap 360B may have stabilizing ribs 362 or the like.

[128] The adjustable buoyancy head float 350 has buoyancy configured prior to release for a particular implementation. For example, the buoyancy of the head float 350 is configured for towed streamer 60, the depth at which towed streamer 60 should be towed, towing speeds, etc. If necessary, the head float 350 on the towed streamer 60 may also include a depth-controlled float similar to the float 220 on the source 200. In this case, it may be necessary to source the fluid and transfer it from the vessel to the float 350 in a manner similar to that described above. .

[129] FIG. 9B is a cross-sectional side view of a head float 350 according to the present disclosure. In the general case, the float 350 is similar to the floats 250 with the adjustable buoyancy of the source 200 discussed above.

[130] For example, as shown in FIG. 9B, the float 350 includes a body 370 and end caps 360A-B. The main body 370 has an outer shell 303 surrounding the floating material 374. The main body 370 has a hollow core 376 in which a plurality of buoyancy elements 380 and / or gaskets 390 are held. Each of the buoyancy elements 380 has a foam insert that can be surrounded by a reinforcing rim. Gaskets 390 do not have foam and instead are simply neutral rings that can be made, for example, from pipe sections of high density polyethylene.

[131] The buoyancy generated by the float 350 located in the water can be adjusted or adjusted using the buoyancy elements 380 and gaskets 390. For example, one of the end caps 360A-B (or both) can be removed from the main part 370 and the hollow core 376 the main part 370 can be filled in the required ratio with buoyancy elements 380 and gaskets 390. The buoyancy of each of the adjustable floats 350 is configured for a specific towed braid (60), to maintain which float 350 is placed, or taking into account other factors noted in oh application.

3. Rejectors of braids

[132] In FIG. 10 shows an example of a streamer diverter 400 that can be used in conjunction with the disclosed system to maintain a towed streamer or seismic source. This braid deflector 400 has a frame 404 holding one or more shutters or vanes 402 designed to be in contact with water when towing. Other 400 braid diverter configurations may be used.

[133] Since the braid diver 400 supports towed streamers (60) towed below the surface of the water, it is preferred that the braid diver 400 has neutral buoyancy. Accordingly, the braid diverter 400 may have a buoyancy element or a float 406 located on it and connected to it, which is designed to impart neutral buoyancy to the braid diver 400 at a predetermined immersion depth. In addition, the braid diverter 400 may have steered wings (not shown) disclosed elsewhere in this application to control the immersion depth of the braid diverter 400 when towing.

[134] In one example, the buoyancy element 406 can be filled with foam or the like, so that the buoyancy of the element can be set for a specific immersion depth prior to release. In fact, for the adjustable buoyancy of the element 406, components similar to the adjustable buoyancy float disclosed above with reference to FIG. 8A-8D and 9A-9B.

[135] Otherwise, in addition to any foam, the buoyancy element 406 may include a fill volume (eg, a soft reservoir or chamber) disclosed in this application to configure its buoyancy and control by immersion depth. For example, in FIG. 10B schematically shows details of a braid deflector 400 having a dynamic buoyancy element 406.

[136] As expected, the braid deflector 400, when towed in water, acts as a wing or a flap. Under the influence of gravity, the deflector 400 braids moves to greater depths, movement in water affects the ascent of the deflector 400 braids to the surface, and tow cables pull the deflector 400 braids in the water. Finally, the buoyancy element 406 affects the maintenance of the diver 400 spit at a given depth in the water. In addition, the geometry of the braid deflector and the applied forces must be such that the braid deflector 400 remains stable in the water when towing and does not rotate and reload due to the action of the torque.

[137] To maintain immersion depth and stability, the buoyancy element 406 may include a depth sensor 401, a controller 405, and a buoyancy chamber 407. In response to changes in depth beyond a predetermined level detected by the depth sensor 401, the controller 405 can adjust the buoyancy of the camera 407 to change the immersion depth of the braid diverter. For example, the controller 405 may actuate a valve or pump, and the chamber 407 filled with air may be filled with water or water may be removed from it. In fact, in the buoyancy element 406 for the scythe diverter 400, it is possible to use immersion depth control components similar to the components of the depth-controlled float discussed above with reference to FIG. 6-7 and incorporated by reference in patent applications.

[138] As additional reference information in FIG. 10C shows a perspective view of only a towed streamer spacing section. The braid deflector 400 according to the present disclosure is shown connected to the cables 62, 63, 66 and 68 with respect to the towing cable-cable 65, the head float 350 and the towed braid 60. In this case, the braid deflector 400 has a frame 404 holding one or more shutters or vanes 402, designed to come into contact with water when towed in it. In addition, the braid diverter 400 may have a buoyancy element or a float 406 located on it and connected to it, which is designed to give the diver 400 braids neutral buoyancy at a given depth. The tow rope 62 from the skeg (not shown) is connected to the guide slings 63 connected to the diverter 400 braids. A drop cable 66 is connected from it to the tow cable 65 and the wiring cable 68 for the towed braid 60 shown. This arrangement is assumed to be given as an example, since other arrangements may be used depending on the implementation.

4. Control Devices

[139] As noted above, in the system 10, control devices 80 on the towed streamer 60 can be used to control the position and depth of the dive. For reference, FIG. 11A shows a perspective view of a controlled stabilizer 87a that can be used to guide a towed streamer 60 (i.e., adjust the lateral position of a towed streamer 60). In addition, in FIG. 11B shows a side view of a guided wing 87b that can be used to adjust the immersion depth (ie, vertical position) of the towed streamer 60. Details of such devices having stabilizers or wings placed on the cable for adjusting the lateral position or vertical position of the towed cable braids can be found in US Patent Nos. 6525992, 7092315, 7206254 and 7423929, each of which is incorporated into this application by reference. Another suitable device that can be used when releasing towed equipment and to obtain the required explode is disclosed in WO2013 / 059926.

[140] These guided stabilizers or wings 87a-b in system 10 may be DIGIFIN ™ towed streamer systems, available to ION Geophysical to provide towed streamer guidance. In addition, they can be DIGIBIRD ™ towed streamer guidance systems, available to ION Geophysical to control the immersion depth of towed streamers. (DOGIBIRD is a registered trademark of ION Geophysical Corporation.)

[141] The control of the stabilizers or wings 87a-b and the determination of the positions of the sensors 70 can be performed using the control system (40 in FIG. 6-7) on the vessel 30 and the available software. In addition, you can use other devices, including systems with a magnetic compass attached to a towed braid, available to ION Geophysical and providing information about the compass direction, as well as depth measurement and control. In addition, with the help of the control system (40) and the available software, it is possible to control various stabilizers and wings 87a-b in order to avoid icebergs or large blocks of ice that may turn out to be floating on the surface for a group of towed streamers (20) (60) and potentially having a depth of penetration into the water sufficient to damage the submerged towed streamers (60).

E. Monitoring the position of towed components

[142] In addition to controlling the buoyancy and position of the three-dimensional array of 20 towed streamers 60 using the components and methods disclosed above, adequate monitoring and tracking of the position of source 200 and seismic towed streamers 60 in arrangement 20 is required when seismic data is recorded so that it was possible to build accurate images. Since towed components are below the surface of the water, you cannot use some common methods of monitoring and tracking positions.

[143] As schematically shown in FIG. 5A, a fully connected speaker network is used to determine the position of the seismic towed streamers 60 of the system and sensors 70. Using the network, the position along the arrangement of 20 towed streamers in two dimensions is determined and the position in three dimensions between the vessel 30 and the head floats 350 of the towed streamers is also determined. When determining the position in two dimensions, a transverse connection is used between the towed braids 60. When determining the position in three dimensions, a towed instrument nacelle 510 is used, located in front of the front end of the arrangement 20, at a different depth compared to the immersion depth of the towed braids 60.

[144] As shown in more detail in FIG. 12, one or more transceivers 520 on a ship 30 interrogate a transponder (s) 522 located at one or more sources 200 to determine the position of seismic sources 200 during seismic operations. In addition, one or more transceivers 520 on the vessel 30 may interrogate transponders 522 located on the head floats 350 of the towed streamers 60 to determine the positions of the head parts of the seismic towed streamers 60 during seismic operations. Otherwise, if there are restrictions on the propagation of signals, one or more transceivers 530 at sources 200 may interrogate transponders 522 located on the head floats (float) 350 for the same purpose.

[145] To obtain position information in an additional plane, the towed instrument nacelle 510 is towed behind the vessel 30 (eg, from skeg 100) using a cable or tow cable 512, at a depth deeper than the immersion depth of the towed streamers 60 of arrangement 20. One or more transceivers 520 on a vessel 30 interrogate a transponder 522 located on a towed instrument nacelle 510, and one or more transceivers 540 on a towed instrument gondola 510 interrogate a transponder 522 located on source 200, and a transceiver defendants 522 on head floats 350 towed streamers 60.

[146] In conventional three-dimensional seismic exploration, the source 200 and towed streamers 60 are towed close to the surface of the water, which forms a solid plane, and GPS readings of the positions of the components can be obtained to monitor and track this information during the exploration. However, in the presented system 10, the towed arrangement 20 of the towed streamers 60 and the sources 200 are located below the surface of the water, so that the system 10 does not have such consistent and accurate position information. Instead, a planar arrangement 20 above is interrogated from the towed instrument nacelle 510, and the non-planar network is formed without using a global positioning system on the surface. Thus, the position information obtained by the towed instrument nacelle 510 helps to further refine other position information obtained in the system 10, so that the processing of seismic data and imaging can be improved.

[147] Various types of transceivers 520, 530, 540 can be used to at least determine the distance to transponders 522. Preferably, transceivers 520, 530, 540 can determine distance as well as direction (bearing). For example, transceivers 520, 530, 540 may be acoustic transceivers, such as transceivers of an ultrashort baseline system for receiving distance and direction information. Transceivers 520, 530, 540 may use other acoustic signals for positioning, such as short base line system signals and long base system signals.

[148] In order to increase the efficiency of the front speaker network, the towed instrument nacelle 510 with its deep-sea towed acoustic platform for overhead viewing provides distance determination in three dimensions. This makes it possible to measure in the system 10 the immersion depth of the various towed components. The movement of the towed instrument nacelle 510 is compensated so that an acoustic system for determining distance or location based on an ultrashort base can be used. In addition, inertial navigation systems on a towed instrument nacelle 510 can be used to monitor and track its position.

[149] With the additional determination of the positions of the towed streamers 60 and other components in the arrangement 20, you can use methods of transverse communication, dead reckoning and other methods. For example, in FIG. 13 shows only part of a system 10 having one towed streamer 60 with sensors 70 located therein to determine the shape of the towed streamer 60. The system 10 uses GPS readout (x) for vessel 30, known sensor positions (Y1-Y5), known the position (Y6) of the tail of the towbar 60 and various compass directions. As shown, data about the sensors 70 and the position of the tail of the towed streamer 60 (including each of the positions (Y) of the sensors on the towed streamer 60, compass directions corrected for magnetic declination, etc.) can be used to estimate the position of the points on the towed spit 60 and obtain the form of a towed spit. All this data, combined with the GPS readout (X) on the ship, obtained using the on-board GPS receiver 550, can be combined with the position data from the inertial navigation system to correct the error due to the departure of the parameters. Whenever possible, at the tail unit 555 it is possible to obtain GPS readings at least from time to time.

[150] For example, as shown in FIG. 14, in systems 10, various speaker arrangements can be used to effect acoustic transverse coupling to determine the position of the towed streamers in the arrangement 20. Each towed streamer 60 towed from the vessel 30 may have acoustic sensors 560 distributed thereon so that the acoustic signals found between towed streamers 60 could be used in cross-linking methods to triangulously determine the positions of towed streamers 60.

[151] The above description of preferred and other embodiments is not intended to limit or narrow the scope or applicability of the concepts of the invention proposed by the applicant. The ideas of the present disclosure can be applied in two-dimensional, three-dimensional or four-dimensional seismic exploration in ice-covered or obstructed waters, as well as in normal conditions of marine seismic exploration. In fact, the ideas of this disclosure can be used in any environment, and not just in environments prone to physical barriers or obstacles. For example, regardless of weather conditions, severe swell, noise, any common hazards, and even under normal conditions encountered in marine seismic exploration, it is possible to benefit from the present disclosure system.

[152] In addition, aspects and methods discussed in relation to one specific embodiment, implementation or arrangement disclosed in this application can be combined or combined with aspects and methods discussed in other specific embodiments, implementations and arrangements disclosed in this application. In exchange for the disclosure of the concepts of the invention contained in this application, the applicant claims all patent rights granted by the attached claims. Therefore, it is intended that the appended claims include all modifications and changes to the full scope when they fall within the scope of the following claims or their equivalents.

Claims (49)

1. Marine seismic equipment for the vessel, while the equipment contains: a lot of towed components receiving seismic data, while towed components are towed by the vessel in horizontal alignment and are immersed at the first levels below the surface of the water; at least one first transceiver located on the vessel, at least one first transceiver emits a first signal and detects first information about the position of the towed components in horizontal alignment with the first signal; and at least one second transceiver towed from the ship and submerged to a second level below the surface of the water, at least one second transceiver emits a second signal and detects the second position information of the towed components from the second signal; a processor that processes the first and second position information and generates data on the position of the towed components in a horizontal arrangement for reference to the obtained seismic data, and the generated position data takes into account the non-planar network of towed components immersed in the first levels in horizontal arrangement. 2. The equipment according to claim 1, comprising a releasable device towed from a ship and having at least one second transceiver. 3. The apparatus of claim 1, wherein the first position information comprises distances of at least some towed components from at least one first transceiver. 4. The apparatus of claim 1, wherein the first position information also comprises bearings of at least some towed components with respect to at least one first transceiver. 5. The apparatus of claim 1, wherein the second level is below the first level. 6. The apparatus of claim 1, wherein the towed components comprise towed braids immersed in first levels towed horizontally, and wherein the apparatus also comprises cross-link equipment located along the towed braids, the cross-link equipment emits a third signal and detects third information about the position of the towed braids on the third signal. 7. The apparatus of claim 1, wherein each of the at least one first and one second transceiver comprises an acoustic transceiver. 8. The apparatus of claim 7, wherein each of the first and second signals comprises at least one of an acoustic signal for determining a location, a system signal with an ultrashort baseline, a system signal with a short baseline, and a system signal with a long baseline. 9. The apparatus of claim 1, comprising at least one transponder coupled to at least one second transceiver and responding to a first signal. 10. The equipment according to claim 1, in which the towed components are selected from the group consisting of a seismic source, a group of air guns, an electromagnetic source, a magnetic source, a sonar device, a sound generation device, a deflector, an acoustic device, an imaging device and a towed streamer . 11. The apparatus of claim 1, wherein the towed components comprise a seismic source having at least one transponder responding to the first signal. 12. The apparatus of claim 11, wherein the at least one first transceiver located on the vessel comprises: one of at least one first transceiver located on the ship and forming a pair with at least one transponder of a seismic source; and another of at least one first transceiver located at the source and emitting a first signal for additional transponders of the towed components. 13. The apparatus of claim 1, wherein at least one of the towed components comprises a float submerged below the surface of the water and supporting at least one towed component, the float having a configured buoyancy. 14. The apparatus of claim 13, wherein the float comprises: the main part bounding the cavity; and one or more floating inserts located in the cavity and configuring the float buoyancy. 15. The apparatus of claim 14, further comprising one or more gaskets that have neutral buoyancy and are located in the cavity. 16. The equipment according to p. 14, in which the main part contains: a housing having a cavity bounded therein; and at least one end cap attached to one end of the housing and covering the cavity. 17. The apparatus of claim 13, wherein the at least one towed component comprises a towed streamer towed by a vessel and supported by a float, wherein the towed streamer has one or more sensors for sensing a seismic signal. 18. The apparatus of claim 13, wherein the at least one towed component comprises a braid deflector towed by a vessel and supported by a float, wherein the braid deflector is connected to one or more additional towed components. 19. A method of marine seismic exploration from a vessel, the method comprising the steps of: towing a lot of towed components in a horizontal arrangement from a ship, submerged one level below the surface of the water; receive seismic data from towed components; detecting the first information about the position of the towed components in a horizontal arrangement according to the first signal emitted by at least one first transceiver located on the vessel; detecting second information about the position of the towed components in horizontal alignment by a second signal emitted by at least one second transceiver towed behind the ship and submerged to a second level below the surface of the water; and specify the position of the towed components in the non-planar network, immersed in the first levels of horizontal alignment by processing the first and second position information. 20. The method of claim 19, wherein detecting the first position information comprises detecting at least distances of at least some towed components from at least one first transceiver. 21. The method of claim 20, wherein detecting the first position information also comprises detecting bearings of at least some towed components with respect to the at least one first transceiver. 22. The method of claim 21, wherein detecting the second position information comprises detecting distances and bearings of at least some towed components with respect to at least one second transceiver. 23. The method of claim 19, wherein detecting the first position information comprises detecting at least one transponder associated with at least one second transceiver and responding to the first signal. 24. The method of claim 19, wherein the second level is below the first level. 25. The method according to p. 19, in which the towed components contain towed braids, towed in the arrangement, and where the method also contains: radiation of the third signal by cross-link equipment located along the towed streamers; and detection of third information about the position of the towed streamers on the third signal. 26. The method according to p. 19, also containing the binding of the specified provisions to the received seismic data. 27. The method of claim 19, wherein detecting the first position information comprises detecting a seismic source as one of the towed components having a transponder responding to the first signal. 28. The method of claim 27, wherein detecting the first position information comprises: detecting a seismic source using one of the at least first transceiver located on the vessel and pairing with the transponder; and detecting an additional one of the towed components when using another at least one first transceiver located on a seismic source and emitting a first signal. 29. The method according to p. 19, in which the vessel towed towed components submerged to a first level below the surface of the water, comprising maintaining at least one of the towed components with a float submerged below the surface of the water, the float having a configurable buoyancy. 30. The method of claim 29, wherein the at least one towed component is selected from the group consisting of a seismic source, a group of air guns, an electromagnetic source, a magnetic source, a sonar device, a sound generation device, a braid deflector, an acoustic device, a construction device images and towed braids.

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