Abstract: A seismic source having two or more operating heads with a firing chamber pressure vessel of compressed air for generating seismic oscillations at low and ultra-low frequencies (ULF) for marine seismic exploration. The multi-headed sound source increases low frequency signal in ranges from below 1 Hz to around 7 Hz to provide greater penetration of the seismic signal through complex overburden such as salt or basalt, improve velocity model building with methods such as Full Wave Inversion, improve the ability to build blocky reservoir models, and improve resolution by reducing side lobes.

Abstract: A vessel system includes a hull configured to provide buoyancy, one or more seismic sources configured to generate seismic energy, and a deployment apparatus configured to deploy the seismic sources from the hull to a water body or water column. A control system can be configured to operate the deployment apparatus, in order to deploy the seismic sources.

Abstract: A sound source including a first gas filled underwater resonator, a second gas filled underwater resonator connected to the first resonator, where the second resonator comprises a Helmholtz resonator, and at least one excitation member configured to excite the first resonator and the second resonator is disclosed. The first resonator is permanently tuned to produce a first resonant frequency upon excitation by the at least one excitation member and the second resonator is permanently tuned to produce a second resonant frequency upon excitation by the at least one excitation member. The first resonant frequency is different from the second resonant frequency.

Abstract: An air gun intended for use in generating seismic energy impulses, i.e. acoustical waves, in a body of water that provides improved performance by adjusting the length of the firing chamber in order to tune the rise time from zero pressure to peak pressure and to increase or decrease the slope of the initial pulse. By selecting the length of the firing chamber, the rise time of the initial pulse is tuned to increase low frequencies and reduce objectionable high frequencies to help in mitigating damage to marine life and the marine environment and to provide greater penetration of the seismic signal through for example basalt and sub-basalt structures.

Abstract: Techniques are disclosed relating to testing of seismic air guns, for example via bubble tests. According to some embodiments of these techniques, a firing sequence for testing the air guns may be determined that reduces the amount of interaction between firings. Further, firing time delays may also be determined in order to further reduce the interactions. Accordingly, a test of an array of air guns may be completed relatively quickly.

Abstract: A technique provides a source design and method for increasing low frequency output of a marine source array. The approach comprises providing a plurality of airguns. At least some of the airguns are activated to generate an effective bubble energy. The effective bubble energy may be optimized through use, preparation and/or arrangement of the airguns.

Abstract: Systems and methods for optimizing low frequency output of marine sources are described. The marine source arrangements and associated methods disclosed herein seek to fully frequency lock bubbles emitted by airguns in close proximity to one another. In this manner, larger effective bubble volumes can be achieved, thus increasing low frequency output.

Abstract: The invention concerns a device for emitting seismic waves designed to operate by being towed by a vessel. The device of the invention comprises a support of elongated shape; at least one seismic source connected to the support; means to tow the support while holding it in a substantially vertical position.

Abstract: An air gun for use in generating seismic energy impulses operable at pressures below 1000 psi that reduces high frequencies and cavitation around the discharge of the air gun in order to mitigate damage to the marine environment, the air gun providing a sliding seal at the firing piston, an extension of port widths beyond the diameter of the firing piston and capability to control the speed of the shuttle assembly to reduce and eliminate some of the possible causes of the objectionable high frequencies and cavitation.

Abstract: A device is provided for producing an acoustic signal in a liquid medium. The device includes a pneumatic chamber to contain a compressed gas volume, at least one pneumatic exhaust port allowing the compressed gas volume to be released out of the pneumatic chamber, and a shuttle movable along a translational axis during an opening phase, between two positions: a closed position in which the compressed gas volume is enclosed within the pneumatic chamber, and an open position in which the compressed gas volume is released out of the pneumatic chamber through the pneumatic exhaust port, to produce the acoustic signal in the liquid medium. A hydraulic brake is used to brake the shuttle during the opening phase. The hydraulic brake includes a hydraulic chamber and having a hydraulic exhaust area of a hydraulic volume out of the hydraulic chamber, and includes a control for controlling the acoustic signal.

Abstract: An impulse sound source for geophysical studies of the earth for oil, gas and other natural resource exploration and more specifically a streamlined design of a hydraulically controlled sound source that may be inserted into oil wells and bore holes for analysis of geological formations deep beneath the earth's surface.

Abstract: The invention relates to a source device for the emission of seismic waves designed to operate by being towed by a vessel. The source device according to the invention comprises at least three support-beams, a plurality of guns placed along each support-beam, a central hub receiving one end of support-beams and arranged such that support-beams can be deployed according to a star-like geometry, and the means to keep support-beams in this geometry during operation.

Abstract: Techniques are disclosed herein relating to distribution of fluids. These techniques may be useful in, for example, supplying pressurized air to seismic sources (or arrays of seismic sources), such as those used in marine seismic operations. Some embodiments of this disclosure include a pipe that passes through a fluid distribution block. The pipe may be configured such that it is able to slide along and/or twist about a longitudinal axis of the distribution block. This technique may reduce the effects of the various stresses that may operate on marine seismic source equipment as it is towed through a body of water.

Abstract: Devices, systems and methods for land seismic. The devices include an above-ground storage tank in which an acoustic energy source is immersed in liquid. The above-ground storage tank may be portable, reusable, self-supporting and may lay flat when empty of liquid and rise on its own when being filled with liquid. The systems include the seismic source-storage tank device, one or more sensors for recording signals that are generated when the source is activated, and a processor for analyzing the recorded signals for geophysical information. The methods involve methods of inducing seismic waves using the seismic source-storage tank devices, and methods of conducting seismic surveys using the seismic source-storage tank devices.

Abstract: A very low frequency marine seismic source has a reservoir of water (47) feeding water to an aperture communicating with the surrounding water (13). The rate of water flow through the aperture is controlled by a rotor disc (11) and stator disc (9) having holes which overlap to a greater or lesser extent as the rotor rotates. The modulation of the flow of water produces a modulated pressure signal which is radiated into the surrounding water. The device is intended to produce acoustic signals over a band extending down to 0.5 Hz or lower.

Abstract: A marine seismic source array includes multiple strings of marine seismic source elements. A first string has a first specified arrangement of air guns between a beginning of the first string and an end of the first string. A second string has a second, different specified arrangement of the air guns between a beginning of the second string and an end of the second string. The second arrangement is the reverse of the first arrangement. A specified arrangement of air guns may be defined, for example, by a number of air guns in each seismic source element, a chamber volume of each air gun, a spacing of the air guns, or any suitable combination of these and other parameters.

Abstract: A marine air gun generates an acoustic signal in water, for example, during a marine seismic survey. The marine air gun includes digital electronic circuitry. The digital electronic circuitry may control an actuator of the marine air gun, digitize and store data from sensors located on or near the marine air gun, send and/or receive digital communications, store and/or output electrical energy, and/or perform other functions. A marine seismic source system that includes multiple air gun clusters may have a separate digital communication link between a command center and each air gun cluster. Each communication link may provide power and digital communication between the command center and one of the air gun clusters.

Abstract: A steerable seismic energy source includes at least one float. The floatation device includes a device for changing buoyancy thereof. A frame is coupled to the at least one float. At least one seismic energy source is suspended from the frame. At least one steering device is coupled to the floatation device or the frame. The at least one steering device includes at least one control surface and a control surface actuator coupled to the control surface. The actuator is configured to rotate the control surface to generate hydrodynamic lift at least in a vertical direction.

Abstract: A method for selecting parameters of a seismic source array comprising a plurality of source elements each having a notional source spectrum is described, the method comprising calculating a ghost response function of the array; calculating directivity effects of the array; and adjusting the parameters of the array such that the directivity effects of the array are compensated by the ghost response to minimize angular variation of a far field response in a predetermined frequency range. A method for determining a phase center of a seismic source array is also related, the method comprising calculating a far field spectrum of the array at predetermined spherical angles, and minimizing the phase difference between the farfield spectra within a predetermined frequency range by adjusting a vertical reference position from which the spherical angles are defined.

Abstract: A marine air gun generates an acoustic signal in water, for example, during a marine seismic survey. The marine air gun includes digital electronic circuitry. The digital electronic circuitry may control an actuator of the marine air gun, digitize and store data from sensors located on or near the marine air gun, send and/or receive digital communications, store and/or output electrical energy, and/or perform other functions. A marine seismic source system that includes multiple air gun clusters may have a separate digital communication link between a command center and each air gun cluster. Each communication link may provide power and digital communication between the command center and one of the air gun clusters.

Abstract: A marine air gun generates an acoustic signal in water, for example, during a marine seismic survey. The marine air gun includes digital electronic circuitry. The digital electronic circuitry may control an actuator of the marine air gun, digitize and store data from sensors located on or near the marine air gun, send and/or receive digital communications, store and/or output electrical energy, and/or perform other functions. A marine seismic source system that includes multiple air gun clusters may have a separate digital communication link between a command center and each air gun cluster. Each communication link may provide power and digital communication between the command center and one of the air gun clusters.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: A technique provides a source design and method for increasing low frequency output of a marine source array. The approach comprises providing a plurality of airguns. At least some of the airguns are activated to generate an effective bubble energy. The effective bubble energy may be optimized through use, preparation and/or arrangement of the airguns.

Abstract: The device hereof is most preferably an improved performance air gun as sound source for marine seismic exploration for petroleum deposits and it most generally is comprised of, an elongated cylindrical housing bored from each end to a fixed radial wall separating the two bores. The fixed radial wall having a through bore for hollow shaft of air control and release shuttle assembly to reciprocate within. The wall having fixed groove for elastomer shaft seal rings to seal around outside diameter of shuttle shaft and drilled passages for water entry to lubricate shaft seals. Air control end of shuttle assembly having set and release flange and internal bearing. Air release end of shuttle assembly cup shaped air release flange with bearing around outside diameter and seal means. Air control end of cylindrical housing having end cap drilled for air input means. The Air control end cap having bolt on shuttle support shaft with piston rings air input means air valving means and orifice means.

Abstract: System for generating pressure waves for deep seismic surveys operating in an underwater environment below the surface, suitable for investigating subcrustal objectives for prospecting purposes in the search for hydrocarbons and/or minerals. The system comprises one or more autonomous underwater vehicles organized in swarms, independent and coordinated, each housing one or more autonomous acoustic sea sources with self-propelled striker pistons. This system is served by a system of supporting surface stations, for reprovisioning, recovery actions, checking the well-being of the single vehicles and swarms and maintenance. The system is capable of using both conventional and non-conventional self-charged acoustic sea seismic sources. The system is capable of replicating the effect of a conventional source operated from the surface.

Abstract: Data is collected from the integral timing sensor of a marine acoustic source such as an airgun, typically used for seismic measurements. Artefacts in the firing data are used to monitor the firing pressure and optionally the correct functioning of the marine acoustic source.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: An over/under seismic source system includes a first umbilical to a first gun array at a first depth and a second umbilical at a different air pressure to a second gun array at a second, lower depth. The air pressure to the second, lower gun array is tuned so that the periods of the gun bubbles from the higher and lower gun arrays match in order to improve wavefield separation in subsequent data processing.

Abstract: A hybrid water cannon that can be configured in either a recoil mode or recoilless mode. A first barrel is attached to a breech block. Either a second barrel or breech plug is also attached to the breech block on a side opposite the first barrel. With the breech plug attached, the water cannon is in a recoil mode. With the second barrel attached, the water cannon is in a recoilless mode. A chamber containing a propellant charge is in communication with both the first and second barrels. Upon ignition, the propellant charge pushes a charge of water from both barrels simultaneously and in opposite directions. The discharge from the first barrel is used to disable the target ordnance. The discharge from the second barrel counters the recoil. The propellant charge is ignited using an ignition charge in a port intersecting the chamber at an angle other than 90 degrees.

Abstract: A method and apparatus for acquiring seismic signals from beneath a salt region in the earth. In one embodiment, the method includes tuning an air gun array to a first bubble oscillation; towing the air gun array in the water at a depth of at least 10 meters, in which the air gun array has a total volume in a range of about 6780 cubic inches to about 10,170 cubic inches; directing acoustic signals with the air gun array down through the water into the earth beneath the salt region; towing one or more seismic streamers in the water at one or more depths, in which at least one of the depths is at least 10 meters, in which each streamer comprises a plurality of hydrophones disposed therealong; and recording with the hydrophones seismic signals reflected from strata in the earth beneath the salt region.

Abstract: A method and apparatus for acquiring seismic data. In one embodiment, the method includes: moving a first air gun array in the water at a first depth and a second air gun array in the water at a second depth greater than the first depth, in which the total volume of the first air gun array is less than the total volume of the second air gun array, in which the first air gun array is separated from the second air gun array by a distance substantially equal to a shot point interval, firing seismic energy through the first and second air gun arrays through the water into the earth, and recording seismic signals reflected from strata in the earth beneath the water.

Abstract: A marine air gun generates an acoustic signal in water, for example, during a marine seismic survey. The marine air gun includes digital electronic circuitry. The digital electronic circuitry may control an actuator of the marine air gun, digitize and store data from sensors located on or near the marine air gun, send and/or receive digital communications, store and/or output electrical energy, and/or perform other functions. A marine seismic source system that includes multiple air gun clusters may have a separate digital communication link between a command center and each air gun cluster. Each communication link may provide power and digital communication between the command center and one of the air gun clusters.

Abstract: A method for determining a fault in a seismic air gun includes comparing a near field seismic signal measured during operation of the air gun to a reference near field signal and determining the existence of a fault in the air gun when a difference between the measured near field signal and the reference near field signal exceeds a selected threshold.

Abstract: A method for characterizing function of an air gun includes measuring, with respect to time, a parameter related to pressure in a charge chamber portion of the air gun. The measurements with respect to time are used to characterize the function of the air gun.

Abstract: The present invention provides a method and apparatus for positioning a center of a seismic source. The method includes determining a desired center-of-source of the seismic source and selecting one of a first and a second plurality of guns to form the seismic source based upon the desired center-of-source, a center-of-source of the first plurality being different than a center-of-source of the second plurality.

Abstract: A 4D seismic source comprising a series of sub-arrays of guns on flotation devices. Each flotation device has a GPS device. For firing, the guns in the e.g. three sub-arrays identified as being closest to the desired firing location are selected.

Abstract: In the oil industry, the acoustic sounding method is a well-known technique for taking the depth measurements of particular attributes of an oil well or borehole. The method involves sending a short, sharp, clear, loud bang sound down a borehole, normally between the inside wall of the borehole casing, commonly referred to as the annulus and the outside of the production tubing string, and recording the echoes generated. One device for generating the sound needed in the acoustic sounding method is an air or gas pressurized chamber which is discharged at or near the wellhead of the borehole. The sound being generated by this device, commonly known as an acoustic generator, comes from the energy released by the equilibration of the different gas pressures. The current invention is an acoustic generator with an improved microphone and microphone unit design for more efficient and effective echo detection.

Abstract: A method for determining a fault in a seismic air gun includes comparing a near field seismic signal measured during operation of the air gun to a reference near field signal and determining the existence of a fault in the air gun when a difference between the measured near field signal and the reference near field signal exceeds a selected threshold.

Abstract: In the oil industry, the acoustic sounding method is a well-known technique for taking the depth measurements of particular attributes of an oil well or borehole. The method involves sending a short, sharp, clear, loud bang sound down a borehole and recording the echoes generated. One device for generating the sound needed in the acoustic sounding method is an air or gas pressurized chamber which is discharged at or near the wellhead. The sound being generated by this device, commonly known as an acoustic generator, comes from the energy released by the equilibration of the different gas pressures. The current invention is an acoustic generator and its control unit that uses several new and novel features to improve the quality of the sound generated and echoes detected in the acoustic sounding method including a unique and novel design and configuration of the portal between the pressurized chamber and the borehole.

Abstract: A method for controlling timing error in the firing of an idle seismic air gun comprises the steps of identifying an acceptable range of seismic air gun timing error, and identifying a relationship between seismic air gun timing error and an idle period preceding a seismic air gun firing event. The first firing event time following an idle period is then compensated according to the identified relationship to control the timing error within the identified acceptable range. The invention may be implemented using computer means such as machine-readable storage media. The invention may be applied to advantage when air gun firing delays are experienced, such as during selective changes from one air gun group to another air gun group for purposes of achieving a desired center-of-source position.

Abstract: A method and apparatus for controlling seismic sources. The method and apparatus enable firing of a seismic sources at either a precise time or a precise position of the seismic source. Controlling the firing of the seismic source facilitates more accurate seismic data and a more consistent seismic source signature.

Abstract: A seismic acquisition system comprising a remote-controlled buoy for conducting seismic acquisition operations. The buoy comprises an operating system for operating a seismic wave production device on the buoy, a placement system, a communications system, and dynamic position locating system. The seismic acquisition system also comprises a remote control system for controlling the buoy systems. The seismic acquisition system also comprises receivers for receiving the seismic wave and generating a data signal indicative of the received seismic wave. The seismic acquisition system operates by controlling the placement system with the remote control system to position the buoy and then controlling the operating system with the remote control system to produce a seismic wave from the seismic wave production device. The receivers then receive the seismic wave and generate a data signal indicative of the seismic wave.

Abstract: A device including a housing defining a first chamber and a port formed through the housing. A shuttle flange moveably positioned within the first chamber. The shuttle flange moves during a gas-release cycle between i) a closed position blocking the port, and ii) an open position exposing an exit area of the port through which a compressed gas is discharged. A method for generating a seismic pressure pulse in water includes the steps of, confining a compressed gas within a chamber having a port, creating an exit area through the port by moving a shuttle along the length of the port during a gas-release cycle, pre-releasing a charge of the compressed gas through the exit area to create a pre-released bubble, choking the exit area, and producing a primary pressure pulse by releasing a main charge of compressed gas through the exit area.

Abstract: Gas Projection Device that can take many external forms that simulate military munitions being exploded and that contain features that enhance the sound of the explosion and the appearance of smoke and attendant percussion. Such device can be controlled by many different means including electronic remote control.

Abstract: A seismic air gun includes an operating chamber, a firing chamber, a port, and a longitudinally disposed cavity sized and shaped to accept a plurality of wires. A moveable shuttle includes a shuttle flange within the operating chamber at one end and a firing shuttle flange at the other end proximate the port and firing chamber. The return force urging the shuttle from the unloaded position to the loaded position is independent of the radial thickness of the shuttle and is directly proportionate to the difference between a first and a second radial cross-sectional thickness of the shuttle flange. As a result, the return force can be optimized without any resulting loss of structural integrity to the shuttle, thereby allowing the port to stay open longer and increasing the amplitude of the primary seismic wave. Seals allow the gun to operating without water lubrication.

Abstract: In the oil industry, the acoustic sounding method is a well-known technique for taking the depth measurements of particular attributes of an oil well or borehole. The method involves sending a short, sharp, clear, loud bang sound down a borehole, normally between the inside wall of the borehole casing, commonly referred to as the annulus and the outside of the production tubing string, and recording the echoes generated. One device for generating the sound needed in the acoustic sounding method is an air or gas pressurized chamber which is discharged at or near the wellhead of the borehole. The sound being generated by this device, commonly known as an acoustic generator, comes from the energy released by the equilibration of the different gas pressures.

Abstract: Physical parameters are measured for an array of seismic sources, preferably for each activation of the seismic sources. Calibration functions are obtained and the measured physical parameters and calibration functions are applied to a model, which generates a calibrated source signature for the array of seismic sources. Alternatively, the measured physical parameters are applied to a model, which generates a modeled source signature, and then the calibration functions are applied to the modeled source signature to generate the calibrated source signature. Alternatively, modeled source signatures are generated for each seismic source and then the calibration functions are applied to the modeled source signatures to generate a calibrated source signature for each seismic source. Then the calibrated source signatures for each seismic source are combined, preferably by linear superposition, to generate the calibrated source signature for the array of seismic sources.

Abstract: A marine acoustic source system has relativley densely packed energy sources arrayed in a tandem-like fashion along a horizontal plane. Preferably, a longitudinal axis of each source lies orthogonal to a pre-determined towing direction. The system includes protective tubes that encloses supply lines and auxiliary equipment, and a harness. The harness provides the primary mechanical connection for towing the sources through the water. To minimize bending of the supply lines, connectors having angular portions connect the sources to the supply lines. Further, the sources can be arranged such that source connection interfaces for receiving power, hydraulic fluid, or data point alternately in opposing directions. During use, the sources, e.g., air guns, are supported at a predetermined depth beneath the water's surface by a floatation buoy. Upon activation, the sources of a cluster each release individual air bubbles into the water.

Abstract: Disclosed herein is a single point seismic system comprising an array of air guns disposed within a frame. The array includes a cluster of air guns on one of its ends and a reduction in chamber size of the air guns along the length of the array. On the end of the array opposite the cluster the array can comprise a series of air guns whose chamber size is an order of magnitude less than the chamber size of the guns comprising the cluster. The middle of the array can comprise a series of air guns whose respective chamber volumes differ by an order of magnitude. The frame of the present invention is generally wholly submerged during operation and does not interfere with the seismic signal produced by the firing of the air guns.

Abstract: A staggered vertical marine seismic source contains upper and lower arrays (10, 11) of emitters of seismic energy (S11, S12; S21, S22). The upper array (10) is horizontally displaced relative to the lower array (11). The source is used in a marine seismic surveying arrangement that has means for moving the source and at least one seismic receiver. In use, the source is moved through the water in a direction parallel to the direction in which the two arrays are displaced. The arrays (10, 11) are fired sequentially, and the time delay between the firing of the first-fired array and firing of the second-fired array is chosen such that each seismic emitter in one array is fired at the same x- and y-co-ordinates as the corresponding emitter in the other array. The seismic wavefields generated by firing the two arrays are thus generated at the same x- and y-co-ordinates, but at different depths.