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: In-sea seismic energy sources, deployed at or near the seabed, generate seismic waves in earth formations beneath the seabed when activated by a triggering mechanism at a precise time synchronized with seismic data acquisition by sensors deployed at predetermined locations around a well drilled for oil and gas exploration. Seismic waves generated at the seabed travel with more direct and predictable ray-paths through the earth to the sensors. Acquired data, including a precise time and location of the seismic events, are used to provide enhanced borehole and sea-bottom seismic surveys.

Abstract: A valving system is disclosed which generally comprises a body including an inlet and an outlet where the inlet is disposed in fluid communication with a fluid flow passage and the outlet is disposed in fluid communication with a pressurized fluid member, the body further defining an internal bore in which is slidably disposed a piston moveable between a first and a second position such that fluid communication between the fluid flow passage and the fluid flow member is established when the piston is disposed in the first position but not in the second position, an apparatus and to move the piston from the first position to the second position so as to interrupt fluid flow from the fluid flow passage to the fluid member.

Abstract: A well tool in accordance with the invention comprises an attenuation device which attenuates tube waves associated with an elastic wave emission and/or reception set (1, 12). The attenuation device comprises a bubble generator (2) which releases into the well a gas not readily soluble in the well fluid, slightly overpressured in relation to the hydrostatic pressure, in the form of calibrated bubbles which greatly attenuate the parasitic tube waves. The attenuation device is placed above or below the elastic wave emission and/or reception set having a plurality of pickups whose signals are acquired by a local electronic module (14) and/or a source of elastic waves such as a vibrator. A bubble trap (17) is preferably associated with the bubble generator (2) in order to limit the volume of gas to be generated in situ. The invention is applicable to VSP type seismic prospecting and acoustic logging.

Abstract: An acoustic wave energy generator comprises a body having an internal gas-pressurisable first chamber 1 adjoining a second chamber 2 into which a liquid is introduced to cover a vibratable means 4 which may be a flexible diaphragm and is mounted on the second chamber so as to close an associated opening 5 in the second chamber. After the first chamber 1 is pressurised with a first gas a common closed opening between the chambers is opened to cause communication between the chambers 1,2 to permit a shock wave emanating from the first chamber to impinge on the liquid. As a result, the vibratable means 4 is caused to vibrate so as to produce acoustic wave energy in response to the impingement of the shock wave on the liquid. By using different liquids and/or different heights of liquids in the second chamber the generator may be tuned to provide acoustic wave energy with a relatively narrow chosen frequency range or within a chosen substantially single frequency.

Abstract: A method, system and apparatus for producing powerful seismic energy impulses by implosion of an imploding free piston positioned in a container which is adapted to be lowered down into a well in the earth to facilitate the collection of well surveying information about the geological formations of the earth in the vicinity of the well. Holding means maintain the imploding free piston in an initial position or quiescent state, trigger means suddenly release the holding means to cause the free piston to accelerate rapidly from its quiescent state thereby producing a powerful impulse by implosion, damping means arrest the movement of the imploding free piston, and operating means return the imploding free piston to its initial position after completion of its rapid acceleration and damped deceleration. After the imploding free piston is returned to its initial position, the apparatus may be triggered again, as desired, to produce additional powerful impulses by implosion.

Abstract: An automatic resetting apparatus for a water sound-source which apparatus includes a source of high pressure resetting liquid, conduit means for connecting the source to the sound-source, a valve in the conduit means, which valve is, in use, under the direct or indirect influence of an actuating pressure of a sound source charging fluid, is actuable from a first position to a second position at a predetermined low actuating pressure within the charging fluid and will remain in said second position until the pressure within the charging fluid falls to said predetermined low pressure, whereupon the valve returns to the first position, the second position allowing the resetting liquid to pass along the conduit means to reset the sound-source and the first position allowing discharge of the resetting liquid from the sound-source after the sound-source has been reset.

Abstract: An apparatus for producing acoustic waves in water through sudden ejection of liquid mass from a tubular main housing. A first shuttle and second shuttle are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber for confining therein a liquid slug. A pneumatic source together with a pneumatically-operated valve cyclically cause the shuttles 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 through ports in the housing. A calibrated control element for providing the proper pressures to the pneumatically-operated valve ensures proper movement of the shuttles.

Abstract: A process and a device for hydrodynamic sound pulse generation in a liquid, n particular for sound pulse generation at sea for marine geophysics measurements.

Abstract: A controlled implosive downhole seismic source having a substantially hollow closed vessel body adapted to be lowered in a borehole and means for selectively causing at least a portion of the vessel body to implode under pressure thereby producing seismic waves.

Abstract: A long-life, low-maintenance air gun/hydro gun includes a one-piece, integral shuttle having an unusually long hollow shank with a firing piston whose configuration is the mirror image of the operating piston, except for the slightly smaller diameter "D" of the firing piston. The shank length L is at least 2.5 times D, and the whole shuttle is guided by this shank sliding within a shaft seal and bearing assembly. By virtue of this guidance, the perimeters of the operating and firing pistons are always kept slightly spaced from their respective associated cylinder walls for eliminating contact of these pistons with their cylinder walls for advantageously dramatically increasing the total number of operating firing cycles which can be accumulated in use before the need for replacing any worn parts, except for the operating and firing seals which are inexpensive. Thus, this air/hydro gun offers a low-maintenance feature.

Abstract: A water gun seismic source for use in underwater environments has a sleeve valve (100) for opening a jet aperture (37, 101) to enable jets of pressurized water to be emitted for the generation of a seismic signal. The water is pressurized by a drive piston (3) which is reciprocated to a cocked position for pressurizing the water for the jets. A compressed air operated cocking mechanism (4, 7, 8, 76 or 110-199 or 200-260) is coupled to the piston for cocking it. The cocking mechanism may utilize cocking piston (7) slideable on a shaft (4) connected to the drive piston (3) which cocking piston is returned to a position where any load due to such cocking piston is decoupled from the shaft. The sleeve valve (100) may be biased to close the jet aperture ports (101) by compressed air and opened with high timing resolution when the pressurized water held back by the sleeve valve is applied to actuate it (via 40, 41, 50 & 43).

Abstract: An impact tool for linearly accelerating a mass such as in a jack hammer. The tool includes first and second members respectively mounted in sealing relationships in first and second outlets of a chamber. The chamber is initially pressurized with a first quantity of gas which remains constant during the normal operation of the tool. To begin a cycle, the first member is moved toward the second member to sealingly engage the end portions thereof and entrap a first volume of gas therebetween. The volume of the entrapped gas is then reduced by continuing to move the first member. This raises the pressure of the entrapped gas and opens a one-way check valve to place the entrapped gas in fluid communication with the gas in the surrounding chamber. Forward movement of the first member is then stopped which again seats the check valve wherein movement of the first member is reversed so that it moves away from the second member.

Abstract: The liquid slug projector apparatus is entirely pneumatically operated. It comprises a generator having a main housing whose main port fluidly communicates with a liquid body. A first shuttle and a second shuttle are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber for confining therein a liquid slug. A pneumatic source together with a pneumatically-operated valve cyclically cause the shuttles 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 through the main port.

Abstract: A process is provided for optimizing the frequency spectrum of pulses emitted by implosion sources by attenuating the tripping or precursor peak preceding the main peak due to the implosion.A plurality of immersed sources are used at different depths and, by successive tripping of the sources in time defined sequence, all their implosion peaks are phased while attenuating to a very large extent the resultant of the different tripping peaks, which increases the acoustic power emitted and makes the frequency spectrum more homogeneous.

Abstract: A marine air gun is advantageously converted into a hydro gun by substitution of two clamp rings and by convenient addition of various parts, allowing normal air gun firing by triggering with usual solenoid valve. In a presently preferred embodiment, a novel firing chamber is also substituted, providing outwardly-facing piston rings and cylinder encircling this chamber. A special clamp is substituted for that which normally secures operating chamber to firing chamber. An outer-cylinder-defining housing is concentric around the firing chamber, with an annular piston sliding in the annular cylinder space defined intermediate the firing chamber and the new outer housing. This annular piston is propelled by the air blast, suddenly ejecting water slugs from ports in the new outer housing. Also added is a pressure-controlled air-vent valve, responsive to air pressure coupled through passages in an adapter mounted between solenoid valve and air gun.

Abstract: An acoustic energy source or gun for use in an aqueous environment such as in a borehole, a well, or in open water. The apparatus, when lowered into a water occupied borehole or the like, functions to create a series of acoustic impulses without forming bubbles, as a result of the water rapidly infilling an implosion cylinder or chamber. A piston rod assembly is reciprocally mounted in each acoustic chamber and is actuated by a power source to trigger the desired sound creating series of impulses.

Abstract: A device for generating acoustic pulses by driving suddenly into a body lowered in a well a piston having a face in contact with the liquid contained in the well and adapted for sliding inside said body. The device comprises a valve securely fixed to the piston, a second piston and a hydraulic system disposed completely in the body and comprising principally a pump, electro-valves, an equalizing cylinder, a low pressure reservoir and supply circuits, for moving the valve and the piston to a set position and for immobilizing it intermittently.

Abstract: A seismic source drives one or more jets of high velocity water into an underwater environment and then terminates the jets by means of a valve member, the motion of which is controlled to obtain precisely timed high energy seismic pulses to provide reflected signals from which high resolution seismograms may be obtained when the signals are processed.

Abstract: An acoustic source for seismic exploration in a water environment consists of an elongated cylindrical housing, closed at both ends and containing laterally disposed exhaust ports. A reciprocable piston and piston follower are slidably mounted within the housing for reciprocal movement. Pressurized hydraulic fluid is admitted to one end of the housing, forcing the piston follower to contact the piston and move towards the opposite end of the housing. A pneumatic latching device retains the piston proximate opposite cylinder end and pressurizes the system. The hydraulic fluid is drained, allowing the piston follower to return to its original position. During the return trip of the piston follower, water is ingested through the exhaust ports to the chamber between the piston and the piston follower. A triggering mechanism then releases the piston that is accelerated towards the piston follower, to impulsively expel the contained water. The ejected water creates a momentary cavity in the surrounding water.

Abstract: The liquid slug projector apparatus is entirely pneumatically operated. It comprises a generator having a main housing whose main port fluidly communicates with a liquid body. A first shuttle and a second shuttle are slidably mounted inside the main housing. The first shuttle forms with the main housing a slug chamber for confining therein a liquid slug. A pneumatic source together with a pneumatically-operated valve cyclically cause the shuttles 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 through the main port.

Abstract: The invention relates to seismic sources in which a shock wave is produced in a liquid mass by the implosion of a volume of vapor, particularly water vapor. According to the invention, the vapor to be imploded is formed inside a closed, flexible enclosure, surrounding an injection head, fitted with a vapor opening 103 capable of releasing vapor at 5 bars and 170.degree. C., controlled by an electromagnetic valve. Liquid nuclei are advantageously introduced into this vapor by means of a pipe for cold water which is under pressure and under the control of an electromagnetic valve, this water arriving in the cavity in order to exit through spray openings. These nuclei produce a vigorous drop in pressure inside the vapor, and hence an implosion and a shock wave, after which a pipe allows the condensate to be recovered. The invention is of use notably as a seismic marine 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: The device includes two movable members interconnected at their periphery by a flexible membrane defining therewith a tight enclosure of variable volume, a piston slidable in a cylinder integral with one of the two movable members and hydraulically actuated, to move the members apart from each other, a second cylinder separated in two compartments by an inner valve and controlling the actuation of the piston in response to the pressure of the water feeding said second cylinder, two apertures intermittently freed by the valve for releasing the piston and at least one aperture for the discharge of the water from the tight enclosure to the external water body when the piston release allows the two movable members to be urged toward each other, thereby producing an implosion which generates a strong sonic wave.

Abstract: Device for generating acoustic waves by implosion in a fluid medium comprising fluid-operated means to move a piston, having one end face in contact with said fluid, from a retracted position in the enclosure to a spaced apart position of maximum extension towards the exterior of the enclosure or vice versa and intermittent locking means for maintaining the piston at its spaced apart position, said fluid-operated means being actuated by two sources of fluid at different pressures, one of which is said fluid medium and the other a source of lower pressure.

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: An acoustic source is provided where a high pressure fluid is used to positively control the period an exhaust valve is open. High pressure fluid is introduced to the control chamber at a predetermined instant after the exhaust valve or shuttle has been opened. This results in conservation of air used to fire the acoustic source and also to achieve a desired signature.

Abstract: The controllable implosive sound projector is comprised of a geometrically shaped cavity within a housing with a material across the face of the cavity. The air within the cavity is evacuated so as to form a vacuum causing a pressure differential to be formed across the material when the projector is submerged in a fluid. At a predetermined pressure differential the material is ruptured creating a shock wave at the face of the cavity which propagates into the cavity with a concave wave front deformation due to the confined boundaries of the cavity that forms a spherical shock wave at the interior of the cavity. At the focal point of the cavity, the spherical shock wave collapses and an impulse wave is generated that causes a pressure wave to radiate out from the opening into the fluid.