Abstract: The embodiments herein describe a seismic source that includes at least two firing heads connected to a shared reservoir of compressed gas. When underwater, a controller can instruct the firing heads to fire at the same time or at different times to create gas bubbles that generate seismic energy for identifying structures underneath a body of water. If the firing heads fire at the same, the resulting gas bubble may coalesce to form a single bubble, depending on the size of the respective bubbles and the separation distance between the firing heads. In one embodiment, the firing heads are attached at opposite ends of the shared reservoir (although this is not a requirement). The length of the reservoir, which dictates in part the separation distance of the firing heads, can be set so that gas bubbles generated by the firing heads at substantially the same time coalesce.

Abstract: An air gun for generating seismic waves in a marine environment includes a cylindrical body configured to hold compressed air and having plural air ports for releasing the compressed air from inside the cylindrical body, the cylindrical body extending along a longitudinal axis X, and an extension member attached externally to the body and extending along a radial axis R, which is perpendicular to the longitudinal axis X. The extension member promotes ambient water flowing inside an air bubble generated when the compressed air is released outside the body.

Abstract: An underwater sound source includes a cylindrical body having a front body portion, a rear body portion, a cylindrical piezo-ceramic ring transducer disposed therebetween, a flexible sleeve configured to cover an outer surface of the cylindrical piezo ceramic ring transducer, and a resonant pipe mounted to the cylindrical body and surrounding the cylindrical piezo-ceramic ring transducer. The resonant pipe is disposed around the cylindrical piezo-ceramic ring transducer, forming a gap between an inner surface of the resonant pipe and the outer surface of the cylindrical piezo-ceramic ring transducer.

Abstract: A low frequency underwater sound source for use in an autonomous underwater vehicle includes a cylindrical body having a front portion, a rear portion, a cylindrical piezo-ceramic ring transducer disposed therebetween, and a resonant pipe surrounding the transducer. A gap is formed between an inner surface of the pipe and an outer surface of the transducer. Alternatively, the sound source includes a cylindrical body, a front fairing disposed forward of the cylindrical body, a plurality of metal rods connecting the front of the cylindrical body and the rear of the fairing, a spherical piezo-ceramic transducer disposed between the cylindrical body and the fairing, and a resonant pipe mounted at the front end of the cylindrical body. The spherical transducer is disposed within a cavity within the resonant pipe. A cylindrical orifice is formed between the front end of the resonant pipe and the rear of the fairing.

Abstract: A method for generating acoustic waves under water includes actuating first and second pistons with an actuator system provided inside an enclosure of a source element, to generate a wave having a first frequency, and actuating the first and second pistons with a pressure mechanism attached to the enclosure, to control a pressure of a fluid inside the enclosure such that a pressure of the fluid is substantially equal to an ambient pressure of the enclosure. The enclosure has first and second openings and the first and second pistons are configured to close the first and second openings.

Abstract: Embodiments relate to the restriction of gas flow in a piston-type marine vibrator to compensate for air-spring effects. An embodiment provides marine vibrator comprising: a containment housing; a piston plate; a fixture coupled to the containment housing; a mechanical spring element coupled to the piston plate and to the fixture; a driver coupled to the piston plate and to the fixture; and a variable gas flow restrictor disposed in an interior volume of the marine vibrator, wherein the marine vibrator has a resonance frequency selectable based at least in part on the variable gas flow restrictor.

Abstract: Method, source and shuttle configured to generate acoustic waves under water. The seismic source includes a housing; a movable shuttle located inside the housing and configured to move between a closed position and an open position along a longitudinal axis X of the housing; a compensator block located inside the housing and configured to move along the longitudinal axis X; a first static seal system configured to seal a first interface between the housing and the movable shuttle in the closed position; and a second static seal system configured to seal a second interface between the movable shuttle and the compensator block in the closed position.

Abstract: An electrical connector including first and second connector parts configured for mating together, and with one of the connector parts having a sensory feedback member that moves between an extended position and a retracted position as a result of magnetic interaction with an actuation element in the other connector part during mating of the connector parts. The movement of the sensory feedback member causes a sensory feedback indication, such as an audible sound or a tactile vibration.

Abstract: A system may include a conduit coupled between a marine seismic source and a gas reservoir external to the seismic source. The conduit may have at least one adjustable dimension for changing a resonance frequency of the system. The system may be utilized in a method of marine seismic surveying.

Abstract: A seismic data acquisition system includes a recording unit to record acquired seismic data and ground equipment containing surface units and wireless field digitizer units. Each surface unit is in communication with the recording unit and contains a first wireless communication module and a power supply mechanism transmitter coil. Each wireless field digitizing unit includes a seismic sensor unit, a second wireless communication module in communication with the seismic sensor unit and one of the first wireless communication modules to exchange digital data between the first and second wireless communication modules and a power supply mechanism receiver coil. The power supply mechanism receiver coil is magnetically coupled to the power supply mechanism transmitter coil in one of the surface units to transmit electrical energy wirelessly from the surface unit to the wireless field digitizer.

Abstract: Disclosed are methods and systems for controlling spread and/or depth in a geophysical survey. An embodiment discloses a submersible deflector, comprising: an upper portion comprising an upper fin section and upper foils disposed below the upper fin section, wherein at least one slot is defined between the upper foils; and a lower portion coupled to the upper portion and disposed below the upper portion, wherein the lower portion comprises a lower fin section and lower foils disposed above the lower fin section, wherein at least one slot is defined between the lower foils. Also disclosed are marine geophysical survey systems and methods of performing geophysical surveys.

Abstract: A method to generate a tube wave in a tubular system involves reciprocating a plunger in a chamber system to alternatingly increase and decrease net volume, drawing fluid from and returning the fluid to a tubular system and into and from the chamber system, to generate a tube wave, and guiding the tube wave to the tubular system. Also, a tube wave generator-sensor system has a chamber system, a plunger, a driver to reciprocate the plunger within the chamber system to generate a tube wave, a flow passage to guide the tube wave into a tubular system, and a sensor to receive the tube wave signal and/or response from the tubular system. The method and system can work with or without a firing valve and or accumulator, without adding or subtracting fluid from the tubular system.

Abstract: A resonant source element is configured to generate seismic waves in water. The resonant source element includes a housing having two openings covered by first and second pistons, wherein the first and second pistons are configured to freely translate relative to the housing to generate the seismic waves; and a high-pressure system configured to discharge inside the housing and to actuate the first and second pistons. The first and second pistons are configured to oscillate after the high-pressure system is fired to generate low-frequency seismic waves.

Abstract: A method of controlling a marine seismic streamer towed by a vessel includes deploying a workboat next to a section of the streamer and receiving, at the vessel, from the workboat, a command to enter a maintenance mode. In response, a locking command is transmitted via a streamer data link to direct a bird attached to the streamer to lock movable surfaces thereof. A user interface on the vessel is locked so that control of the bird is no longer available therethrough. A control apparatus for marine seismic operations includes the user interface, a receiver to receive commands from the workboat, a streamer interface to command the birds, a memory recording locations and identifiers of the birds, and a processor configured to carry out the method steps. A marine seismic detection system includes the streamer, a maintenance controller in the workboat, and an integrated navigation system controller in the vessel.

Abstract: Embodiments relate to marine acoustic vibrators that incorporate one or more piston plates that act on the surrounding water to produce acoustic energy. An example marine acoustic vibratory may comprise: a containment housing; a piston plate; a fixture coupled to the containment housing; a spring element coupled to the piston plate and the fixture; and a driver coupled to the piston plate and the fixture and configured to move the piston plate back and forth.

Abstract: Method, source array and source element that generate seismic waves. The source element includes an enclosure having an opening covered by a piston; a local supply accumulator fluidly communicating with an interior of the enclosure, a pressure of the fluid inside the local supply accumulator being larger than a pressure of the fluid inside the enclosure; a local supply valve located between the local supply accumulator and the enclosure and configured to control a flow of the fluid from the local supply accumulator to the interior of the enclosure; and a controller configured to control the local supply valve such that the pressure inside the enclosure does not fall below a first preset value based upon an ambient pressure of the enclosure while seismic waves are generated.

Abstract: Embodiments relate to the restriction of gas flow in a piston-type marine vibrator to compensate for air-spring effects. An embodiment provides marine vibrator comprising: a containment housing; a piston plate; a fixture coupled to the containment housing; a mechanical spring element coupled to the piston plate and to the fixture; a driver coupled to the piston plate and to the fixture; and a variable gas flow restrictor disposed in an interior volume of the marine vibrator, wherein the marine vibrator has a resonance frequency selectable based at least in part on the variable gas flow restrictor.

Abstract: Embodiments relate to marine vibrators that incorporate one or more piston plates that act on the surrounding water to produce acoustic energy. An example marine vibrator may comprise: a containment housing; a piston plate; a fixture coupled to the containment housing; a mechanical spring element coupled to the piston plate and the fixture; a driver disposed in the marine vibrator, wherein the driver is coupled to the piston plate and the fixture; and a container coupled to the piston plate, wherein the container is configured to hold a variable mass load; wherein the marine vibrator has a resonance frequency selectable based at least in part on the variable mass load.

Abstract: A source element for generating seismic waves includes a housing; a partitioning element placed inside the housing and configured to split the housing in a closed chamber and an opened chamber; and a valve in fluid communication with the closed chamber and configured to supply high-pressure air to the closed chamber to make the partitioning element oscillates. An oscillation of the partitioning element generates low-frequency seismic waves.

Abstract: A device for exciting seismic vibrations includes a hydraulic cylinder comprising first and second caps; a partition configured to divide the cylinder into first and second chambers; a rod and piston assembly configured to move in the first chamber; an actuator connected to a rod of the assembly; a first plate connected to the assembly and configured to move in the second chamber; a waveguide configured to move in the second chamber; and a second plate connected to the waveguide. The assembly comprises an axial through channel in a body of the assembly. The actuator is configured to move the rod of the assembly in the through channel between first and second positions. In the first position, a first flow is prevented between first and second sides of the first plate. In the second position, the first flow is allowed between the first and second sides of the first plate.

Abstract: In one aspect, an apparatus for use downhole is provided, which apparatus, in one embodiment, includes an acoustic transducer having a first member in pressure communication with a confined fluid, wherein a displacement of the first member causes a volume change in the confined fluid that amplifies displacement of a second member to generate a pressure wave in medium.

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: 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: 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: An acoustic reflector primarily for underwater use comprising a shell surrounding a core in which holes are provided in the shell to allow air and water freely to enter and leave the interior of the shell when the reflector is immersed in water. Various embodiments are described including the use of a metal shell matched to a water core, the use of a mounting bar, provision of a frame to reflect acoustically alpha numeric characters, a soluble plug to delay operation of the reflector, and coating the reflector with polyurethane to limit damage. Also proposed is a pulse pattern to improve the identification of an acoustic reflector in some circumstances. Designs of reflectors particularly suitable for use with the relatively low frequency sonars found in the fishing industry with an aluminum or aluminum alloy shell are described, as are reflectors with a non-metal shell suitable for use with the higher frequency sonars in the underwater exploration industry.

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: A marine vibrator with improved seal is described. The marine vibrator includes a housing and piston within the housing for generating vibratory signals. The improved seal is comprised of a two-stage seal having a first seal disposed adjacent the water interface and a second seal disposed away from the water interface, thus improving the reliability of the marine vibrator.

Abstract: The invention concerns a device for emitting seismic waves designed to operate by being towed by a vessel, characterized in that it comprises means capable of discharging compressed air under high pressure into water, to generate a bubble (44) of a general annular shape.

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: Disclosed are electromagnetic linear actuators used in acoustic vibratory sources for marine seismic surveying. An embodiment discloses a linear actuator for acoustic sources, comprising: magnetic circuitry comprising a gap; and a coil assembly comprising: a drive coil, wherein at least a first portion of the drive coil is configured to be moved in a linear path in the gap; a pair of ferromagnetic coil guides positioned on either side of the linear path; a first ferromagnetic extension extending laterally from the first portion of the drive coil; and a transmission element coupled to a top side of the first portion of the drive coil. Embodiments also disclose acoustic vibratory sources, marine seismic survey systems, and methods of marine seismic surveying.

Abstract: A sound source includes a bubble configured to be filled with a gas. The sound source also includes an actuator configured to perturb the gas within the bubble by changing the volume of the gas without adding gas to or removing gas from the bubble. The sound source also includes a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

Abstract: A disclosed seismic source assembly includes a body having a cavity and a seismic source positioned in the cavity. The cavity is in fluid communication with the water via an aperture oriented in a first direction. One or more surfaces of the body define a water contact significantly larger than an area of the aperture and on a side opposite the first direction. A described method includes forming a source assembly by: providing a cavity having an aperture for transmitting seismic waves; rigidly attaching a base to a side of the cavity opposite the aperture, where a transverse area of the base is significantly larger than an area of the aperture; and positioning a seismic source in the cavity. The source assembly is submerged in the water and triggered.

Abstract: A marine vibratory sound source for producing swept or pulse coded signals in a body of water and within geological structures beneath a body of water, primarily for seismic exploration of the strata beneath the bottom of the water. More particularly, a high power, servo controlled hydraulic, sound source that can readily be towed in water, towed along the bottom surface under the water or be used in a stationary position on the bottom surface under the water.

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 system comprises marine geophysical equipment, adapted for towing through a body of water; and tightly fitting covers, attached to the marine seismic equipment, to fill-in indentations in the marine geophysical equipment, for gathering marine geophysical data. A method comprises marine geophysical equipment having tightly fitting covers, to fill-in indentations in the marine geophysical equipment, attached thereto, for gathering marine geophysical data.

Abstract: A seismic source includes a flextensional shell defining a longer axis and a shorter axis and at least one driver coupled to the flextensional shell proximate an end of the shorter axis. The seismic source may be a component of a marine seismic survey system. The marine seismic survey system may be utilized in a method of marine seismic surveying.

Abstract: A sound source includes a tubular resonator configured to be filled with a gas. The exterior of the resonator includes rigid and elastomeric portions. The interior of the resonator includes a first volume and a second volume. The volumes are separated by a rigid tubular wall containing at least one orifice. The at least one orifice enables a flow of gas between the volumes. The resonator also includes at least one rigid tubular member configured to move along the rigid tubular wall. The position of the at least one rigid tubular member regulates at least one dimension of the path between the volumes. The sound source also includes a volume velocity actuator disposed within the resonator. The sound source also includes a processing circuit configured to provide a control signal to cause the volume velocity actuator to perturb the gas within the resonator at a defined frequency.

Abstract: The invention concerns a device for emitting seismic waves designed to operate by being towed by a vessel, characterized in that it comprises means capable of discharging compressed air under high pressure into water, to generate a bubble (44) of a general annular shape.

Abstract: A disclosed seismic source assembly includes a body having a cavity and a seismic source positioned in the cavity. The cavity is in fluid communication with the water via an aperture oriented in a first direction. One or more surfaces of the body define a water contact significantly larger than an area of the aperture and on a side opposite the first direction. A described method includes forming a source assembly by: providing a cavity having an aperture for transmitting seismic waves; rigidly attaching a base to a side of the cavity opposite the aperture, where a transverse area of the base is significantly larger than an area of the aperture; and positioning a seismic source in the cavity. The source assembly is submerged in the water and triggered.

Abstract: A marine seismic source comprises a housing having a central axis, an open end, and a closed end opposite the open end. In addition, the seismic source includes a piston extending coaxially through the open end of the housing. The piston is adapted to axially reciprocate relative to the housing. Further, the piston has a first end distal the housing and a second end disposed within the housing.

Abstract: A seismic energy source includes an inlet aperture and an inlet pipe in fluid communication with an outlet of the inlet aperture at an inlet end of the inlet pipe. The inlet pipe is in fluid communication with an accumulator at an outlet end of the inlet pipe. An outlet pipe is in fluid communication with the accumulator at an inlet end of the outlet pipe and is connected to an outlet valve at an outlet end of the outlet pipe. The outlet valve is actuated by fluid pressure in the outlet pipe. An actuation pressure of the valve, and diameter, length and material properties of the outlet pipe are selected to cause a reflected water pressure wave resulting from closure of the valve to travel within the outlet pipe at a selected velocity. Motion of the seismic source through the water provides water pressure to operate the source.

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 sound source comprises a bubble configured to be filled with a gas, an actuator configured to perturb the gas within the bubble, and a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

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: 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: A sound source comprises a bubble configured to be filled with a gas, an actuator configured to perturb the gas within the bubble, and a processing circuit configured to provide a control signal to the actuator to cause the actuator to perturb the gas within the bubble at a frequency defined by the control signal.

Abstract: A seismic source array 15 comprises a plurality of seismic source 26 arranged about a central point of the source array 15 in such a way that an imaginary circle drawn with said central point at its center, and containing all of said seismic sources 26, can be divided into at least three whole sectors each of which contains a substantially identical arrangement of seismic sources 26.

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: 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.