RU2607076C1 - Method of controlling seismoacoustic towed streamers and positioning device for its implementation - Google Patents

Abstract

FIELD: geophysics.

SUBSTANCE: invention relates to geophysics and can be used for marine seismic survey. Proposed is an automated positioning device (APD), which is a body of neutral buoyancy, the housing of which represents two tightly coupled cavities interconnected in such a way, that a system of through channels is formed between them, via which water is pumped between end nozzles and nozzles equipped with special shutters located near screws of low-noise hydraulic propulsions creating a variable thrust, the force and the direction of which are controlled by the propulsions screw direction and the shutters degree of opening-closing. APD is also equipped with a hydrophone for registration of own noise and noise of the incident water flow, an electronic accelerometer and an electronic gyroscope, detail acoustic distance meters for determining the distance between APD installed on adjacent seismoacoustic towed streamers. In the proposed method proposed is a control over the seismoacoustic towed streamers using such APD. Seismoacoustic towed streamers are released from special bottom wells in the vessel stern. Coordinate referencing is performed by the automated method from a research vessel. Target distance between adjacent towed streamers, as well as between sensitive elements in each antenna is set in accordance with previously calculated coordinate grid. Performed is automatic control over the depth of the towed streamers immersion, as well as control over the position of the towed seismoacoustic streamers in the crosswise and the lengthwise directions without interruption of the working cycle of surveys and retrieving the towed streamers onboard the vessel.

EFFECT: technical result is higher accuracy of the survey data.

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Description

The invention relates to the field of geophysics and can be used when conducting marine seismic work on the shelf of the Arctic seas in difficult ice and weather conditions or other (technogenic) pollution of the sea surface.

An automated method for controlling the immersion depth, shape and distance between seismic-acoustic streamers in a system consisting of one or more streamers, released from the bottom mines of a specialized icebreaking research vessel and towed behind it, and a device for its implementation are proposed.

In most modern methods (Marine seismic exploration / Ed. By A.N. Telegin. - M .: Geoinformmark LLC, 2004. - 237 p.), Geophysical exploration, 4d, 3d and 2d seismic profiling of the bottom of marine areas means towing by a ship- carrier system of seismic acoustic streamers. In systems with multiple seismic streamers, seismic streamers tow under water behind a research vessel almost parallel to each other. To arrange their location in space, hydraulic parasols (or their analogues), a flexible coupling limiting the maximum divergence of braids, a system of stretch marks defining this difference, a tail buoy (or reflector), positioning the tail of the braid, and specialized floating elements (positioning devices) are traditionally used, able to deflect the working section of the braid in one direction or another in the transverse direction ("birds"). A GPS receiver is often located on the tail buoy, which allows for rigid coordinate snapping of the tail spit segment. To regulate the immersion depth of the antenna, a load (or “bird”) is placed in its front part, which, due to the tension of the carrier cable (or the direction of traction given by the bird), sets the starting point of the horizontal section of the braid.

We single out the most obvious technological features of seismic surveys carried out in the traditional way and making it difficult to use in difficult ice and weather conditions:

- the tail buoy is towed to the surface, due to the need to register GPS / GLONASS data, or to carry out radio communication with it;

- the working section of each braid is positioned by a mechanical system of weights and stretch marks; to adjust the parameters of this system, it is necessary to interrupt the research work cycle and select the braids on board the vessel, where the agreed adjustment is made.

The closest in technical essence to the proposed method is described by RF patent No. 2516591 (Method and system for controlling seismic streamers: RF patent for invention No. 2516591: IPC G01V 1/38 / Sil Daniel B. (US), Grant John Edward (GB) , Cespedes M. David A. (US); Ion Geophysical Corporation (US) - Application No. 20111116289/28; filing date of the application 06.11.2009; publication date of the application 12.20.2012, Bul. No. 35; date of publication of patent information 20.05 .2014, Bull. No. 14. - 18 pp.: 6 ill.) A way to control seismic streamers. This patent proposes a method and system for controlling the shape and distances in an arrangement of seismic streamers towed behind a research vessel.

This patent proposes a method and system for controlling the shape and distances in an arrangement of seismic streamers towed behind a research vessel. Each seismic streamer is controlled in the transverse direction by means of positioning devices (so-called steering devices) located along its length at specific nodes to achieve a predetermined distance from the adjacent seismic streamer. One of these valid seismic streamers, used as a reference for other valid seismic streamers, is controlled to achieve a predetermined distance from an imaginary, or phantom, seismic streamer that is virtually towed along with the actual seismic streamers.

The disadvantages of this invention include the fact that the coordinate snapping is carried out on the basis of data received on the control system from the surface parts of the antenna system (tail buoy of a seismic streamer), the presence of which can lead to a collision of the streamer with floating obstacles (ice floes or other technogenic objects) and as a result, its damage. Another disadvantage is that the adjustment of the position of the braids is carried out only in the transverse direction, which makes it impossible to use the braids at low speeds of the vessel or when it stops. In addition, when maneuvering the ship, slowing down or stopping the ship (which is especially important for the icebreaker in the start-stop mode) or in the presence of strong currents due to the lack of adjustment of the position of the braids in the longitudinal direction, the working sections of the braids sag and there is a strong shift to inadequate coverage of the research area with a network of seismic streamers, and therefore to distortion and insufficient amount of data obtained. As a result, in those territorial areas of the shelf where the information is insufficient, additional measurements are carried out, that is, braids are again towed over a specific section to “thicken” the resulting data array. The disadvantage is that the adjustment of the position of the braids in depth is carried out using a mechanical cargo system, which requires the selection of braids on board the vessel.

In addition, positioning devices, through which the prototype proposes to control seismic streamers, use engines and hydrofoils for this. In addition to the fact that it does not allow these devices to control the braids in the longitudinal direction, which automatically implies the numerous disadvantages of the prototype method, but these devices are also very noisy, and nowhere in the prototype method is it mentioned that the noise produced by the positioning devices is significantly affect the quality of measurements, that they need to be measured and taken into account when processing intelligence data to improve the accuracy of measurements.

The task to which the invention is directed is to increase the accuracy of exploration data obtained as a result of measurements made during the towing of seismic-acoustic streamers, expand the range of speeds for towing seismic-acoustic streamers to low speeds (up to a complete stop of the vessel), automate tracking and adjusting the spatial location of workers plots of braids without interrupting the work cycle of studies, increasing the safety of seismic-acoustic braids during the measurement process.

The technical result in terms of the method is ensured by the fact that one or more seismic-acoustic streamers are released and towed behind the vessel, the working sections of which are antennas with sensitive elements equipped with positioning devices located in spaced positions along the length of the seismic-acoustic streamer, determine the shape and mutual location of towed seismic-acoustic streamers, coordinate them and set the target distance between adjacent seismic-acoustic braids, Steering commands are transmitted to positioning devices to arrange the relative position of towed seismic braids and adjust the distance between adjacent braids, and they also control the position of towed seismic braids in the transverse direction and control the plunge depth.

What is new is that seismic-acoustic braids are released from specialized bottom mines in the stern of the research vessel, the coordinate reference is carried out automatically from the research vessel, the target distance between adjacent braids, as well as between sensitive elements in each antenna, is set in accordance with a pre-calculated coordinate grid, they control the depth of immersion of the streamers, as well as control the position of the towed seismic-acoustic streamers not only in the transverse, but also in the longitudinal directions using the same automated positioning devices, adjust the distance between the braids, the distance between the sensing elements on the working sections of the braid and the depth of immersion of the braids without interrupting the research cycle and selecting braids on board the vessel.

The technical result in terms of the device is ensured by the fact that the positioning device is a neutral buoyancy body equipped with a coupling device for fastening in certain nodes of the seismic-acoustic spit.

New is that the body of the neutral buoyancy body consists of two hermetically conjugated cavities, connected in such a way that a system of through channels is formed between them, connecting the end nozzles and nozzles of the propulsors, which are installed in certain places of the through channel system and have a thrust vector that is adjustable by means of shutters placed on the device’s body near the nozzles of the propulsors, as well as by the fact that it is equipped with a hydrophone for recording its own noises and noises flowing around the air in s, electronic accelerometer and gyroscope electronics, acoustic rangefinders, repeater digital data stream.

The invention is illustrated in FIG. 1-3.

In FIG. 1, an automatic positioning device for controlling the position of towed seismic-acoustic streamers is presented: 1 - neutral buoyancy body, 2 - neutral buoyancy body casing, consisting of two hermetically conjugated cavities, 3 - system of through channels formed by mating cavities, 4 - thrusters with a variable thrust vector ( low noise), 5 - end nozzles, 6 - nozzles for movers 4, 7 - shutters for adjusting the nozzle clearance 6 for movers 4, 8 - hydrophone, 9 - accelerometer, 10 - electronic gyroscope, 11 - acoustic range finders, 12 - repeater of the digital data stream, 13 - coupling device for fixing the UAP in certain nodes of the seismic-acoustic spit.

In FIG. Figure 2 shows various options for violating the spatial arrangement of antennas and the direction of traction created by automatic positioning devices to correct violations (shown by arrows).

In FIG. 3 is a flowchart of an embodiment of a method for controlling seismic-acoustic streamers using automatic positioning devices.

The proposed automated positioning device (hereinafter referred to as UAP) is (Fig. 1) a neutral buoyancy body 1, the housing 2 of which consists of two hermetically conjugated cavities, which are connected in such a way that form a system of through channels 3 connecting the end nozzles 5 and nozzles 6 for movers 4, which are located in certain places of the through-channel system 3 and have an alternating thrust vector, which is ensured by adjusting the clearance of nozzles 6 for movers 4 (adjustment is carried out using shutters 7 ) and the direction of rotation of the propeller propellers 4. The UAP is also equipped with a hydrophone 8 for detecting intrinsic noises and noises surrounding the flow of water, an electronic accelerometer 9 and an electronic gyroscope 10, used to determine the speed and spatial orientation of the device, narrowly focused acoustic range finders 11, designed to determine the distance between UAPs installed on adjacent antennas. Among other things, the UAP is equipped with a digital data stream repeater 12, through which it is connected to a common digital data network of the antenna and gets the opportunity to exchange information with the central post of the control complex located on the carrier vessel. Each such UAP is installed in certain nodes of the seismic-acoustic streamer and is rigidly fixed using the coupling device 13.

The proposed method for managing seismic streamers using the above UAP is as follows.

In the process of performing seismic-acoustic studies from special bottom mines located in the aft part of the bottom of the research vessel, one or more seismic-acoustic streamers are produced, the working sections of which are solid-state digital hydroacoustic antennas with sensitive elements, and give a signal to start the research cycle. Further, for positioning and setting the relative position of the braids, UAPs installed in certain antenna nodes are used. A flowchart of an embodiment of a method for controlling seismic-acoustic streamers using an UAP is shown in FIG. 3. After receiving a signal to start the duty cycle from the central post of the control complex located on the vessel, each UAP determines its own spatial orientation, direction and speed of its movement. To do this, use the data of the electronic accelerometer 9 and the electronic gyroscope 10. After determining the specified parameters, all UAPs transmit them to the central post of the complex, using a digital data stream repeater 12 for this.

In response, from the central post of the complex transmit information about the binding of the UAP to a specific node of the previously calculated spatial coordinate grid, data on the required distance to the UAP located on adjacent braids, the required depth. Having received these data, each UAP using acoustic range finders 11 checks the compliance of the real values of these values with the required values. If in the process of this action deviations of the indicated values from the required values are detected, they are adjusted using the UAP. To do this, calculate the offset value, which must be compensated. Having obtained this value, the UAP includes one or more of the respective propulsors 4. The ability of the propulsors 4 to work in reverse mode and the system of through channels 3 make it possible to use several of the total number of propulsors 4 in this process, which reinforce each other.

The UAP is directly displaced with the help of the pressure created by the movers 4 and pumped through the system of through channels 3 and directed in the necessary direction by means of shutters 7, which regulate the nozzle clearance 6 of the movers 4. Depending on the direction in which the UAP must be shifted, they can be pumped water from several of the end nozzles 5 to one or more of the nozzles 6 of the movers 4, from one or more of the nozzles 6 of the movers 4 to one or more others of the nozzles 6 of the movers 4, from several end Opel 5 to several other mechanical nozzles 5 and one or more of the nozzles 6 have propulsors 4.

After giving the UAP the required impulse, the movers 4 turn off and again check the binding to a specific point in the spatial coordinate grid. If the presence of deviation is again detected, the process is repeated. If the deviation is not detected, then the UAP is transferred to the position monitoring mode, in which the device’s binding to the coordinate grid is periodically checked and constant attempts are made to detect deviations in the location of the UAP. When such deviations are detected, the position adjustment process is restarted (Fig. 2).

Through the repeater of the digital data stream 12 from each UAP also transmit information from hydrophones installed on the same spit to the central post of the complex.

If in the process of carrying out the relevant research by the research complex there is a need to change the depth of immersion of the braids or the distance between them, then information will be transmitted to all UAPs with new data on the required distances between the UAP and the required depth. All UAP begin to manipulate the movers 4 to bring these parameters into line with the new requirements. This process continues until it is established that the spatial location parameters and the depth of each UAP meet the new requirements.

If the vessel’s speed drops or stops during the research complex’s research complex, the signal is sent to all UAPs to turn on the movers 4 in such a way as to maintain the working position of the antennas.

Thus, the determination and adjustment of the spatial position of the working section of each seismic-acoustic streamer is carried out in an automated way, using specialized software for the control complex on the vessel, for which, along with an advance description of the geometric parameters of the antenna system and the vessel, data are used on the speed and course of the vessel, as well as data from an electronic accelerometer 9, an electronic gyroscope 10, and data from acoustic range finders 11 located in each N and GPS / GLONASS data received from the respective receiver ship.

The hydrophone 8 of the UAP is designed to register noise arising from the operation of the UAP and noise from the flow of the UAP with an incident liquid flow. A digital recording of these noises is transmitted to the central post of the control complex, where it is subsequently used to take them into account when processing seismic data.

It can be noted that, unlike the prototype method, in which the spatial position of the braid in the transverse direction and in depth is adjusted using several different devices, in the proposed method, adjustment is also carried out in the longitudinal direction, i.e. adjusting the distance between the sensitive elements on the working sections of the braid, and they do it all with the help of the same device - UAP.

Sensitive elements on the working sections of the streamer (hydrophones) are equipped with gyroscopes and accelerometers. Given their tight binding to the UAP through the cable, you can uniquely determine their position, which makes it possible to adjust their position in space and relative to each other. If a deviation of the position of any UAP or sensitive element from a certain position in a previously calculated three-dimensional coordinate grid is detected, the value of this deviation is calculated. The deviated UAP, or the one closest to the deviated sensitive element of the UAP, is instructed to turn on the respective of the propulsion devices 4 with a variable thrust vector to compensate for the detected deviation. Next, the new position of the deviated sensing element is determined and the deviation from the coordinate grid is recalculated. When the deviation exceeds the threshold value, the signal is again applied to turn on the corresponding of the propulsors 4 to compensate for the deviation. With the help of such manipulations, the deviation is sequentially minimized and, thus, the arrangement of sensitive elements in the coordinate grid is ordered. Manipulations to correct the position of deviated sensing elements continue until the deviation is less than the threshold value, the value of which is set in advance. Tracking and adjusting the position of the sensitive elements of the antenna is carried out continuously throughout the working cycle of research.

Thus, using the proposed device (UAP) to implement the method of controlling seismic-acoustic streamers, it is possible to solve the problem posed for this invention and realize the following advantages of the proposed method.

Improve the accuracy of exploration data. The result is achieved due to the continuous maintenance of the braids in working condition throughout the entire measurement cycle, as well as through the use of low-noise propulsors in the UAP and the ability to take into account the distortions introduced by them into the measurement results.

To expand the speed range of towing seismic-acoustic streamers in the direction of low speeds (up to a complete stop of the vessel). This is achieved by continuously maintaining the braids in working condition and in the desired spatial position in accordance with a given coordinate grid throughout the entire measurement cycle, which eliminates the deviation or sagging braids when the ship slows down, including when it stops.

Automate tracking and adjustment of the spatial location of the working sections of the braids without interrupting the research work cycle. The result is achieved through the use of a set of UAPs for adjusting the spatial position of the braids, for the adjustment of which and for the implementation of their functions it is not necessary to select braids on board the vessel.

To increase the safety of seismic-acoustic streamers during the measurement process. The absence of surface parts (buoys, floats, cables, etc.) in the measuring equipment (braids), together with the fact that the braids are discharged from the bottom shafts, minimizes the possibility of damage to the antennas against floating obstacles.

Claims (2)

1. A method for controlling seismic-acoustic streamers, in which one or more seismic-acoustic streamers are released and towed behind a vessel, the working sections of which are antennas with sensitive elements equipped with positioning devices located in spaced positions along the length of the seismic-acoustic streamer, and determine the shape and relative position of the towed seismic-acoustic braids, coordinate them and set the target distance between adjacent seismic-acoustic braids, giving steering commands to positioning devices for arranging the relative position of towed seismic braids and adjusting the distance between adjacent braids, as well as controlling the position of towed seismic braids in the transverse direction and controlling the depth of immersion of the braids, characterized in that the seismic braids are released from specialized bottom shafts into stern of the vessel, coordinate reference is carried out in an automated way from the research court on, the target distance between adjacent streamers, as well as between sensitive elements in each antenna, is set in accordance with a pre-calculated coordinate grid, control the depth of immersion of the streamers, and also control the position of towed seismic-acoustic braids not only in the transverse, but also in the longitudinal directions using the same automated positioning devices, adjust the distance between the braids, the distance between the sensitive elements on the working sections of the braid and the depth of the dive Nia braid without interrupting the cycle of research and choosing the braid on board the vessel. 2. A positioning device, which is a neutral buoyancy body, equipped with a coupling device for fastening in certain nodes of the seismic-acoustic spit, characterized in that the body of the neutral buoyancy body consists of two hermetically conjugated cavities, connected in such a way that a system of through channels connecting them forms end nozzles and nozzles for propulsors that are installed in certain places of the through-channel system and have a thrust vector that is adjustable by means of shutters, times eschennyh on the housing near the nozzle device in propulsion, and in that it is equipped with a hydrophone for recording the intrinsic noise and noise incident flow of the water flow, electronic accelerometer and gyroscope electronics, acoustic rangefinders, repeater digital data stream.

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