Design of automatic control system for position of line of air guns

Abstract

FIELD: geophysics.SUBSTANCE: invention can be used to control the position of a line of air guns during marine seismic operations. Essence: the automatic control system for the position of the air gun line contains on-board control unit (IV), towing vessel (I), and umbilical cables (II) connecting vessel (I) with the air gun lines. Moreover, each line of air guns is float support (1) with a keel and air guns. Each float support is equipped with a thruster and a hydraulic unit. The thruster is equipped with a wing with a convex-concave profile, rear and control levers, brackets, a sensor module, and a hydraulic cylinder, which is a means of adjusting the angle of the control lever. The hydraulic unit includes a control unit, an electric motor connected to a pump, as well as a hydraulic unit, valves, a hydraulic accumulator, and pressure, level, and temperature sensors. The hydraulic unit control unit is equipped with a controller that collects data from the sensors of the thruster and the hydraulic unit, as well as controls the valves of the hydraulic unit and sends the collected data to the software package of on-board unit (IV) for controlling the system.EFFECT: increasing the efficiency and reliability of controlling the position of the air gun line.1 cl, 8 dwg

Description

[0001] The invention relates to the field of geophysics and is intended to control the position of lines with suspended pneumatic sources when a vessel passes along a design profile.

[0002] A system for controlling marine devices towed by ships using a float having wings is known (CN 115335730 A published 11 / 11 / 2022). The installation comprises: a hull having means for towing behind a ship; means for connecting to an underwater marine seismic installation and supporting it, as well as for lateral control of the underwater marine seismic installation in the water; and means for remote control from the ship. The hull of the installation has a floating unit located at the front, with an extended rear float hinged to the rear of the front float. The front floating unit has a vertical wing with means for adjusting the angle of attack in the water.

[0003] A method is known for controlling a streamer positioning device configured to be attached to a marine seismic streamer and towed by a seismic exploration vessel, and having a wing and a wing motor for changing the orientation of the wing. The method includes the steps of: obtaining an estimated speed of the streamer positioning device, calculating a desired change in the orientation of the wing using the estimated speed of the streamer positioning device, and actuating the wing motor to obtain the desired change in the orientation of the wing. The invention also includes a device for controlling the streamer positioning device, including means for obtaining an estimated speed of the streamer positioning device, means for calculating a desired change in the orientation of the wing using the estimated speed of the streamer positioning device, and means for actuating the wing motor to obtain the desired change in the orientation of the wing (US 20090238035, published September 24, 2009).

[0004] A system for controlling cables and streamers is known (US 20040060498, published 01.04.2004). The system for controlling cables and streamers in a seismic towing assembly includes at least one deflector connected to one side of a tugboat by at least one wire, leading or the like, wherein the deflector is located in a position at a distance perpendicular to the direction of movement of the tugboat, wherein the vessel is equipped with a navigation system for measuring the position of the vessel. The system is characterized in that it contains a command unit and a number of control units, wherein the control units are located on at least some of the streamers and are adapted to measure and report their positions, that the command unit contains means for receiving position information from each individual control unit and calculating possible deviations from the specified positions, and that the system contains means for changing the position of the streamers to re-establish the positions of the control units.

[0005] Dynamic control foil systems and methods are known (RU 2729696, published August 11, 2020). Each foil system includes a positively buoyant device, a pair of control cables, a plurality of hydrofoil sections, and an actuator. The pair of control cables may be attached to the floating device and extend downward from the floating device to the submerged end. The plurality of hydrofoil sections may be arranged along the direction of the control cables between the floating device and the submerged end. The actuator may be configured to adjust the angles of attack of the hydrofoil sections by varying the tension of one or both control cables. Directional control is performed in several modes, described by data distributed through a control system in communication with the foil systems.

[0006] A control system and method for controlling a towed offshore object (RU 2806020, published October 25, 2023) are known, which comprises one or more towing elements extending between the object and the towing vessel. One or more ballast elements are movably connected to a corresponding one of the one or more towing elements and are controllably movable at least a distance along their corresponding towing element. The towed object can be controlled by moving one or more ballast elements on the towing element to control the sag of the towing element. Individual ballast elements can be individually adjusted to correct, maintain, or change the geometry of the trawl.

[0007] A towed and steerable device for a marine seismic source is known (EP 2776862 A1, published September 17, 2024), which has a first fastening means in the lower part of the float body for providing the possibility of suspending at least one seismic source from the float and a second fastening means in the front part of the float body for attaching a towing cable or umbilical cable of the force-receiving source. The float body comprises first and second elongated steering wings attached and located at a distance from the respective left and right sides of the front part of said float body using a corresponding support device.The rudder wings have corresponding longitudinal axes oriented in a direction substantially perpendicular to the longitudinal axis of the float body, and so as to be substantially perpendicular to the sea surface during use. The extended rudder wings have corresponding first and second chord axes. The control means adjust the angle of at least one of the first and second chord axes relative to the longitudinal axis of the float body.

[0008] Technical solutions of the known level of technology have a number of disadvantages associated with the use of actuators that ensure the movement of the thruster.

[0009] The closest technical solution to the invention is a system for controlling the position of a pneumatic source line (Russian Federation patent for invention No. 2849089, published on October 22, 2025).

[0010] A system for controlling the position of a line of pneumatic sources, comprises a towing vessel, a ship navigation system, a communication channel, at least one line of pneumatic sources with a float, wherein the system comprises:

[0011] - an on-board control unit located on a vessel and configured to calculate the required rotation angles for the thruster of the pneumatic source line based on information received from the vessel's navigation system about the current parameters associated with the position of the pneumatic source line relative to the design profile, with the ability to transmit a control signal to the thruster, while the on-board control unit is connected via a communication channel to the vessel's navigation system;

[0012] The pneumatic source line position control system comprises at least one thruster device comprising a monofoil secured by means of at least one lever on a float of the pneumatic source line, and comprises a monofoil position angle sensor;

[0013] • an actuator configured to set the angle of attack of the monowing, wherein the actuator includes a motor and a linear drive;

[0014] • an on-board control unit installed on the float of the pneumatic source line, wherein the on-board control unit is designed with the possibility of exchanging data via communication channels between the on-board control unit, the actuator and the monowing position angle sensor.

[0015] The disadvantages of the prototype include:

[0016] - the prototype description lacks information about the attachment point of the towing cable to the float, which is one of the most important factors affecting the success of seismic exploration work, namely: if a non-optimal attachment point is selected, a torque may occur that will turn the line of pneumatic sources across the current, thereby significantly increasing hydrodynamic resistance, causing the entire system to yaw and reducing the efficiency of controlling the lines of pneumatic sources using the thruster;

[0017] - the lack of algorithms to prevent the convergence or collision of lines within a group and thrusters on the middle lines of pneumatic sources can lead to equipment damage, overlapping of towing cables, increased mutual influence of gas bubbles formed by pneumatic sources on different lines, and even an emergency shutdown due to loss of control over the system.

[0018] The technical problem is to eliminate the specified deficiencies.

[0019] The technical result of the invention is to increase the efficiency and reliability of the system by improving its maneuverability, increasing the wing lift coefficient and the accuracy of positioning the pneumatic sources relative to the design profile.

[0020] The air source line is a float support with a keel and air sources suspended from it.

[0021] A float support is a device that provides neutral buoyancy for pneumatic sources towed behind a vessel.

[0022] A pneumatic source is a pulsed non-explosive source of seismic vibrations in which compressed air serves as the energy carrier;

[0023] Separation is the distance between the centers of the lines of pneumatic sources (or the centers of their groups) projected onto the normal to the central line of the design profile.

[0024] The technical problem is solved and the technical result is achieved by the fact that the design of the automatic control system for the position of the pneumatic source lines in the design of the ACS PLP contain umbilical cables II connecting the vessel I with the pneumatic source lines, a thruster 3 mounted on the keel III of each float support 1, in its bow part, while the thruster 3 is equipped with a wing 4, a rear lever 5, a control lever 6, brackets 9, a sensor module 7, a hydraulic cylinder 10, which is a means for adjusting the angle of the control lever 6, while, according to the invention, the float support 1 contains a hydraulic unit 2, which is installed on the keel III of each float support 1 behind the thruster 3. The hydraulic unit 2 includes a control unit, an electric motor connected to a pump, as well as a hydraulic unit, valves, a hydraulic accumulator and pressure sensors, level and temperature.The control unit, located in the hydraulic block, is equipped with a controller that collects data from sensors that control the hydraulic block valves and sends this information to the software package. Onboard system control unit IV, located on vessel I, routes signals between the software package and the control unit. An automated operator station, located on the vessel with the installed software package, receives data from the external shipboard inertial navigation system regarding the location of each line of pneumatic sources. Wing 4 has a convex-concave profile, with the ability to mount a float support on one side of the hull. A thruster is mounted on fin III of each line of pneumatic sources, in the bow, with an umbilical cable attached to the opposite side of fin III, in the area where the wing's lift is applied.

[0025] The invention is explained with the help of drawings.

[0026] Fig. 1 shows a schematic arrangement of the main design elements of the ACS PLP when a vessel is towing lines of pneumatic sources, each of which is a float support with a keel and pneumatic sources suspended from it (the dots indicate the centers of the groups of lines of pneumatic sources);

[0027] Fig. 2 shows the elements located on the float support;

[0028] Fig. 3 - side view of the thruster (wing not shown);

[0029] Fig. 4 - bottom view of the thruster;

[0030] Fig. 5 - top view of the thruster;

[0031] Fig. 6 - enlarged view with the installation location of the hydraulic cylinder;

[0032] Fig. 7 and Fig. 8 - general views of the thruster from different sides.

[0033] The drawings indicate the following positions:

[0034] I - vessel;

[0035] II - hose cables;

[0036] III - keel;

[0037] IV - on-board system control unit;

[0038] 1 - float support;

[0039] 2 - hydraulic unit;

[0040] 3 - thrusters;

[0041] 4 - wing;

[0042] 5 - rear lever;

[0043] 6 - control lever;

[0044] 7 - sensor module;

[0045] 8 - base;

[0046] 9 - brackets;

[0047] 10 - hydraulic cylinder.

[0048] The design of the ACS PLP is used for 2D, 3D and 4D marine seismic operations.

[0049] The design of the PLP ACS ensures:

[0050] - distribution of pneumatic source lines according to the towing configuration;

[0051] - maintaining the lines of pneumatic sources on the trajectory of movement by compensating for external influences (current, sea waves, wind, vessel yawing on the position of pneumatic sources) during seismic exploration work;

[0052] - fixing the wing in the working position during work;

[0053] - fixing the wing in the folded position during preparation for work and after its completion;

[0054] - emergency folding of the wing, followed by fixation, upon command from the vessel;

[0055] - integration (data exchange) with navigation systems (ORCA or similar);

[0056] - necessary electrical cable connections of the PLP control system with the control and power supply system;

[0057] - ensuring separation between groups of pneumatic source lines;

[0058] - ensuring separation within groups of pneumatic source lines.

[0059] The design of the automatic control system for pneumatic source lines contains:

[0060] - hydraulic unit 2 (HU), which is installed on the keel III of each float support 1 behind the thruster 3, and which includes an electric motor connected to a pump, a hydraulic unit, valves, a hydraulic accumulator and pressure, level and temperature sensors, as well as a control unit (CU), which includes batteries, a controller, an RS-485 interface repeater, a Modbus protocol converter;

[0061] - thruster (TU) 3, which is installed on the keel of each float support 1 at its forward end, and consists of a wing 4, a rear lever 5, a control lever 6, brackets 9, a sensor module 7, a hydraulic cylinder 10, which is driven by a pump. Due to the fact that the wing is driven by the front lever, and not the rear one, the entire structure has a more compact arrangement of components. The use of a pump in combination with a hydraulic cylinder 10 ensures high efficiency of the system, improves the position holding of the pneumatic source line without additional devices, and also facilitates rapid response;

[0062] - on-board control unit for the IV system (BCU), which is located on the vessel and includes an uninterruptible power supply, batteries, a redundant power supply, a switch, an AC / DC converter, and a Modbus protocol converter;

[0063] - the automated operator's station is a personal computer with a software package installed on it and is located on the vessel.

[0064] The software package installed at the automated operator station receives data from the external shipboard inertial navigation system “ORCA” on the location of each line of pneumatic sources.

[0065] The controller, which is part of the control unit, collects data from the PU 3 sensors regarding the position of the wing 4, converts and filters the analog signal, and then sends control signals to the BG 2 valves in accordance with the command received from the software package. The controller collects data from the BG 2 sensors regarding the state of the system as a whole and sends this information to the software package.

[0066] The BBUS IV handles signal routing between the software package and the control unit. The BBUS IV also converts signals from Ethernet to RS-485 and vice versa.

[0067] The ACS PLP software package correlates the coordinates of each air gun line with the wing angle of attack and, during seismic surveys, takes into account the compliance of the current trajectory of the air gun lines with the design profile. This calculates the required angle of attack of the wing included in PU 3 to maintain the air gun lines within the specified corridor and to promptly compensate for external influences such as waves, wind, etc., which also improves the quality of seismic exploration. Installing a wing on each air gun line increases the maneuverability of the entire system and improves the positioning accuracy of the following objects: for the entire system; for group centers; for separation between groups; for separation between air gun lines within each group. It also expands the maneuvering range of the air gun lines and increases the speed of drift compensation.

[0068] Thus, thanks to the proposed invention, the technical characteristics of the design of the ACS PLP are improved, namely, the efficiency of using the system is increased, including due to the use of an electric motor, at the same time, the lift coefficient is increased due to the installation of a thruster on each line of pneumatic sources, with an umbilical cable secured to the keel of the line of pneumatic sources, in the nose, on the opposite side from the thruster, in the zone of application of the wing lift force and, as a consequence, an increase in the accuracy of positioning of the pneumatic sources relative to the design profile.

Claims

A design of an automatic control system for the position of a line of pneumatic sources, comprising a towing vessel, umbilical cables connecting the vessel with the lines of pneumatic sources, a thruster mounted on the keel of each float support, wherein the thruster is provided with a wing, characterized in that the thruster is mounted on the keel of each float support in its bow section, and the umbilical cable is secured to the keel of each float support in the bow on the opposite side from the thruster in the area of ​​application of the wing lift force, the thruster is provided with a wing of a convex-concave profile, a rear lever, a control lever, brackets, a sensor module, a hydraulic cylinder which is a means for adjusting the angle of the control lever, wherein a hydraulic unit is mounted on the keel of each float support behind the thruster, the hydraulic unit includes a control unit, an electric motor connected to a pump, and a hydraulic unit,valves, a hydraulic accumulator and pressure, level and temperature sensors, the said control unit is equipped with a controller that collects data from the sensors, controls the valves of the hydraulic unit and sends this information to the software package of the on-board control unit of the system.,

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