Abstract: The present invention provides a method for determining the spacing and size of air guns in a tuned air gun array. Volume ratios are calculated based upon a predetermined maximum volume for any individual air gun. The volumes are cross-referenced to spacings for optimum air gun interaction. The resulting air gun array operates as a broadband high-energy point source.

Abstract: The invention relates to the creation of a shock wave within a mass of water by implosion of a vapor bubble.According to the invention, a controlled quantity of liquid water under pressure and which is super-heated relative to the mass of water is released quickly, at a predetermined point of the mass of water, the water advantageously being in the lower vicinity of the left-hand part of the saturation curve (portion B-D). The water liberated in this way expands and vaporizes at least partially in the form of a single bubble, which then implodes suddenly.Application as a marine seismic source.

Abstract: The liquid slug projector apparatus (9) comprises a generator (10) having a main housing (13) whose main port (17b) fluidly communicates with a liquid body (12). A first shuttle (26) and a second shuttle (61a) are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber (23) for confining therein a liquid slug (22). Force-producing means (8) cyclically cause the shuttles (26, 61a) to move relative to or in locked condition with each other, thereby applying during each cycle of operation an abrupt propulsion force to the confined liquid slug which becomes expelled as a very high-velocity liquid jet (22a) through the main port.

Abstract: A method is described for causing hollow glass spheres to implode on command while deep in the ocean, whereby to produce an acoustic pulse. Specific means for causing the spheres to implode are described. The invention is useful for seismic work.

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having internal sleeve and shuttle control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle engages an internal sleeve having ports that momentarily align with exhaust ports and then moves past, sealing off the exhaust ports before all of the compressed air in the firing chamber of the air gun is exhausted. By preventing further discharge of air with little or no loss in acoustic output, pulses are greatly reduced, thereby enhancing the operation of the entire system. Further by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having shuttle control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle is controlled by secondary shuttle means for closing the exhaust ports before all of the compressed air in the firing chamber of the air gun is exhausted. This point of closing the exhaust ports before virtually all of the compressed air is discharged differs from prior art air guns. By preventing further discharge of air, secondary pulses are greatly reduced, thereby enhancing the operation of the entire system. Further, by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having shuttle control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle is controlled by valve means for closing the exhaust ports before all of the compressed air in the firing chamber of the air gun is exhausted. By preventing further discharge of air, with little or no loss in acoustic output, secondary pulses are greatly reduced, thereby enhancing the operation of the entire system. Further by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having shuttle and external sliding valve control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle is controlled by air pressure to move it upward, thereby permitting compressed air in the firing chamber to exhaust through exhaust ports. The external sliding valve had been held in a downward position by air pressure supplied from the firing chamber, compressing a spring. As the firing chamber pressure drops, the compressed spring expands, forcing the sliding valve to move upward, closing the exhaust ports. By preventing further discharge of air, secondary pulses are greatly reduced, with little or no loss in acoustic output, thereby enhancing the operation of the entire system. Further, by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Abstract: Disclosed is a seismic source device, known in the industry as an air gun, having shuttle control for allowing a predetermined discharge of compressed air into water for purposes of seismic exploration. The shuttle is indirectly controlled by a moveable plate for closing the exhaust ports before all of the compressed air in the firing chamber of the air gun is exhausted. In one embodiment, the plate is freely moveable; in a second embodiment, the plate is attached to the shuttle. By preventing further discharge of air, with little or no loss in acoustic output, secondary pulses are greatly reduced, thereby enhancing the operation of the entire system. Further by preventing all the air in the firing chamber from being discharged, the system becomes more efficient and more cost effective.

Abstract: A device for underwater generation of low frequency sound comprising a coally shaped explosion chamber open at both ends, a firing chamber having inlet and outlet passages at opposite ends thereof, ignition means in the firing chamber, a restricted orifice between the outlet passage of the firing chamber and the small open end of the explosion chamber, a mixing chamber opening into said inlet passage, and two supply lines for introducing gases to form a combustible mixture in the mixing chamber, the combined resistance the supply lines and the mixing chamber offer to the flow of gas in the upstream direction being slightly greater than the flow resistance of said restricted orifice, the arrangement being such that when the gases in the firing chamber are ignited with the device submerged in water the flame spreads down stream through the explosion chamber and also upstream into the supply lines thereby extinguishing the flame.

Abstract: The invention has application to an implosive sound generator which produces in a body of water a cavity that implodes resulting in a large acoustic impulse. The invention provides means for eliminating or substantially reducing the bubble effect by providing means for absorbing the rebound of the implosion of the cavity and preferably also for cancelling the recoil of the generator. A preferred embodiment of the generator comprises a slug chamber having a primary port. The slug chamber entraps a liquid slug therein when the generator is submerged in a liquid body. Force means propel the liquid slug with sufficient kinetic energy to create in the liquid body a main cavity which is imploded by the hydrostatic pressure head. To reduce or eliminate the rebound of the implosion, there is provided a suction chamber having at least one secondary port communicating with the liquid body near the site of the main cavity.

Abstract: In the field of seismic exploration, compressed-air guns may be used as sound sources. Known air guns employed complex valving and were wasteful of compressed air. The air gun sound source of this invention is of simple construction and is economical of compressed air.The gun (10) consists of an elongated housing (34) that has at least one radially-positioned exhaust port. The housing is charged with a volume of compressed air. A hollow cylindrical actuator (60) is mounted inside the housing and may be hydraulically or pneumatically driven within the housing in longitudinal strokes. The actuator has at least one radially positioned aperture (88) alignable with the exhaust port. A valve or sealing pad (96) is mounted in each aperture. An orifice (104) is cut into each pad. At one end of an actuator stroke, the valve blocks the exhaust port in the housing.

Abstract: In seismic exploration, particularly at sea, several seismic acoustic sources selected from different genera of such sources are combined in a single array. The several sources are fired substantially simultaneously so that the acoustic pulses from the several sources blend together to create a single composite seismic wave. The source genera are selected such that their initial impulses are in phase but their caudal transients are incoherent with respect to one another so that the initial impulse is enhanced at the expense of the after-pulses.

Abstract: Apparatus for generating a substantially oscillation-free siesmic signal for use in underwater petroleum exploration, including a bag with walls that are flexible but substantially inelastic, and a pressured gas supply for rapidly expanding the bag to its fully expanded condition. The inelasticity of the bag permits the application of high pressure gas to rapidly expand it to full size, without requiring a venting mechanism to decrease the pressure as the bag approaches a predetermined size to avoid breaking of the bag.

Abstract: A rapid-fire air gun for generating acoustic pulses in a body of water includes a reservoir of high-pressure air, a shut-off valve, and a throttle valve for admitting air to an attached firing chamber. The firing chamber has an exhaust port that is sealed by a spring-loaded exhaust valve. When the shutoff valve is open, high pressure air is admitted to the firing chamber through the throttle valve at a rate depending upon the effective aperture through the throttle valve. The exhaust valve is set to open at some selected pressure and to close at some lower pressure. When the air pressure in the firing chamber exceeds the pressure setting of the exhaust valve, the valve opens to impulsively release a jet of high pressure air which generates an acoustic pulse. When the air pressure in the firing chamber drops, the valve closes and the air pressure again builds up in the firing chamber. A series of such openings and closings generates a pulse train.

Abstract: In seismic delineation of sedimentary section below the surface of a seismic energy propagation medium, a new use for an old article is disclosed. It includes a basic method for generating and shaping a seismic energy pulse comprising (1) generating a first energy pulse downwardly through the shortest distance to a point at the lower end of a vertical straight explosive material for forming a compressional forward portion of the seismic energy pulse, and (2) generating a second energy pulse later to form a rarefactional aft portion of the seismic energy pulse. By varying the length of the explosive material the lengths of the forward and aft portions are varied for controlling the shape of the seismic energy pulse, and by varying the position of the point of ignition of the linear explosive material, additional shaping of the seismic energy pulse results.

Abstract: A method for decreasing the amplitude and period of bubble pulses following a primary seismic energy pulse comprises generating an expanding air bubble around a body and preventing the air bubble from contracting into the body for attenuating the sudden contraction and collapse of the air bubble, and two valve devices on a closed cylinder for carrying out the latter method resulting in minimizing bubble effect and the size of the bubble for decreasing amplitude and period of bubble oscillation for providing a clear, well-defined acoustical wave.

Abstract: An underwater sound imploder adapted for use in the exploration of minerals existing under the sea bed. The imploder consists of three main units, a boiler, a heat shield therefor and a bell shaped sonic device to which the boiler has delivered superheated steam. Expansion of the steam under water pressure causes the implosion. The steam condensate is pumped back into the boiler where it is recycled. The implosions occur repeatedly in the device thereby causing a succession of sonic impulses to pass through the water medium and return as echoes for detection and analysis to determine thereby the character of the reflecting object in the sea bed.