Abstract: A flat, elongate, laminated plate of ceramic piezoelectric material is fixedly mounted on one end to permit movement of the other end responsive to the application of a variable electronic control signal to electrodes on the outer surfaces of the laminated plate. The movement and force applied by the movable end of the plate controls the release of air pressure from the pressure chamber so that the pressure in the chamber varies in response to the variations of the electronic control signal.

Abstract: A hydraulic vibrator having an adjustable piston rod and a fixed piston rod to vary the cylinder volume for operation at different vibration frequencies. The adjustable piston rod is in threaded engagement with the fixed piston rod and has a piston head adjacent a piston head on the fixed piston rod. Rotation of the adjustable piston rod displaces the two piston heads, thereby varying the cylinder volume of the hydraulic vibrator.

Abstract: Vibrator apparatus having adjustable cylinder volume by means of a continuously adjustable end sleeve that varies the axial limit of the cylinder. A reaction mass with an axial cylinder bore reciprocates on a double rod piston. Frist and second end sleeves define the cylinder volume and one end sleeve is threaded and axially translatable relative to the piston to vary volume while a position sensing device continually maintains centering of the piston in the cylinder.

Abstract: The invention relates to a nondestructive downhole seismic source capable of generating S.sub.V -waves, S.sub.H -waves, and P-waves alone or in combination to determine information about a surrounding geologic formation. The invention also includes processes of performing crosswell tomography and reverse vertical seismic profiling. The invention also includes a means and process to carry out in hole seismic logging operations.

Abstract: The ultrasound sensor (2) of the invention comprises a polymer foil (4) which is supported in its outer region and is piezoelectrically activated at least in one portion (42). The portion (42) is coupled electrically to a first electrode (200) in the form of an adjacent, i.e., touching pin. A second electrode (8), in the form of a grid (214) connected to ground and/or a ring (216) connected to ground, is physically separated from the activated portion (42). The pin (200) is connected to the first input of an amplifier (210). The second input thereof is connected to ground. The metallic take-off at the activated zone (42) results in high sensitivity of the ultra-sound sensor (2) which is provided particularly for the measurement of shock waves with a high pressure amplitude and which finds application in lithotripsy.

Abstract: An electro-acoustic transducer has a transducer plate having a piezo-electric layer attached thereto. The electro-acoustic transucer is clamped between bearing members at an annular edge region which is free of the piezo-electric layer. The piezo-electric layer is provided with electrodes which extend into the annular free region of the transducer plate. At least one of the bearing members has electrically conductive zones which press directly or indirectly against the electrodes and which press against electrical plug elements on a housing for the transducer.

Abstract: A dual chamber seismic air gun which discharges both chambers simultaneously to counterbalance the reactive forces generated by the discharges. The chambers are symmetrical within the housing of the gun so that the movement of the internal parts during operation also counterbalance each other. The gun is mounted coaxially on the air supply of a seismic array to provide a good profile for towing.

Abstract: Multistate mud pulsing is achieved by generating both positive and negative pulses within a drill string by means of a plurality of selectively operable bypass passages around a restriction to primary mud flow within a drill string or by venting to outside of the drill string. A fraction of the hydraulic mud is drawn from a location upstream from the restriction into a valve manifold. The removed fraction of hydraulic mud is selectively communicated from the valve manifold either to a point inside a drill string downstream from the restriction or to a point exterior to the drill string in annulus between the outside of the drill string in the borehole. Mud reinjected downstream from the restriction creates a positive pressure pulse within the drill string. Mud which is diverted to the annulus outside of the drill string creates a negative mud pulse within the drill string.

Abstract: A pressure wave sensor device is provided including at least two sensitive flexible piezoelectric elements wound in two helices in opposite directions of a tubular support and a method for manufacturing same, said device including a copper conducting ribbon wound helically between the two windings of opposite direction and in the same direction as the underlying winding so as to avoid short circuits at the crossing points of the turns and to improve the electric and mechanical couplings between the two sensitive elements, said tubular support being provided with collector assemblies at regular intervals and wound over the whole of its length with the sensitive elements and the conducting ribbon, the different windings then being cut to the right length at the level of the collector assemblies and connected electrically thereto.

Abstract: A cylindrical array employs rectangular planar array segments which extend in the axial direction when assembled on a cylindrical conducting plate having flat longitudinal portions to which the planar array segments are attached. Each planar array segment comprises two columns of planar transducer elements with each column extending in the axial direction of the cylinder. The acoustic center of each transducer lies on the circumference of a right circular cylinder. The acoustical requirements of a cylindrical array are satisfied to allow multiple beams to be formed with a minimum of complexity and with the same versatility as in the curved array segment cylindrical array embodiment.

Abstract: A novel device and method are provided herein for the production of underwater sound. This device, termed a plasma jet underwater acoustic source includes a central electrode and a concentric insulator having a longitudinal bore to accommodate the central electrode, the bore being spaced from the central electrode by a longitudinally-extending annular chamber. A plasma cavity is bounded at its upper end by the central electrode, and is in communication with the annular chamber. The cavity is adapted to be connected to a gas supply, so that it may be filled with gas. An outer housing of electrically-conductive material surrounds the insulator and terminates in a centrally-apertured end plate whose central aperture provides an extension to the plasma cavity, the end plate being adapted to be grounded.

Abstract: A wide-range audio frequency underwater transducer is designed to make use of a massive small diameter vibratile piston driven by electromagnetic oscillatory forces to transmit omnidirectional uniform sound pressure level over the frequency range 100 Hz to 5 kHz. The rugged transducer design is adapted for low-cost mass production and can be used as a highly reliable expendable reference standard of source level for the calibration of in-situ stationary or moving sonar receiving systems. The magnitude of the source level can be accurately controlled by the magnitude of the electrical current supplied to the electrical winding over the entire frequency range of operation. A pressure equalization system is included in the design that permits use of the transducer at any depth down to 500 feet.

Abstract: A cable detector has a plurality of rotatably series connected hooks having an opening mouth for accepting a cable on sea bottom with an equal angular intervals, a contact pressure sensing means for indicating that a cable is engaged with one of said hooks by measuring contact pressure on one of the hooks, and an electrical switch which is actuated by said contact pressure sensing means to provide an electrical signal when a cable is detected.

Abstract: The invention relates to an apparatus for the control and monitoring of a well head submerged in a liquid.The apparatus comprises electrovalve control means, an electronic system for controlling and monitoring the well head, monitoring sensors, connecting means connected to the electronic system and a station on the surface of the liquid medium using a transmission line. The electronic system comprises a first channel connected to the control means and to the sensors, supplied with electric power by the line and a second channel for controlling the control means and which is supplied with electric power by said line. The second channel and the electrovalve control means are also connected to an autonomous power supply, which is independent of the line. Each of the channels and the connection established bidirectional communications with the station.Application to the control and monitoring of submerged well heads.

Abstract: The invention provides a method and system for seismic exploration of a body by applying, to the body acoustic energy producing a source wavelet and detecting the response of the body thereto to produce seismic traces. According to the method, at least two receivers are located within the body to output electrical signals corresponding to (1) the pressure field produced at a particular depth in the body as a result of the application of the acoustic energy, and (2) the pressure gradient produced at the depth in the body as a result of the application of the acoustic energy. The electrical signals are processed to estimate the source wavelet and thereby to deconvolve the detected response producing deghosted and spiked seismic traces.

Abstract: A surface acoustic wave device comprising a surface acoustic wave substrate member composed by forming an aluminum oxide film and a thin zinc oxide film successively on a glass substrate. The thickness h.sub.1 of the aluminum oxide film and the thickness h.sub.2 of the zinc oxide film are set within ranges of 0.1.ltoreq.h.sub.1 /.lambda..ltoreq.10 and 0.05.ltoreq.h.sub.2 /.lambda..ltoreq.0.35 (where .lambda. is representative of wavelength of Sezawa wave) respectively, thereby to utilize Sezawa wave or a similar mode wave transmitted on the surface acoustic wave substrate member in multi-layer structure.

Abstract: In the art of acoustic well sounding a gas-gun for the sudden discharge of a measured quantity of compressed gas, comprised of two chambers, viz. a discharge chamber closed at one end by a poppet, and on the opposite end by a power-head, the latter a cylinder including a sealed piston, with the poppet connected by sealed piston rod penetrating the cylinder head, and terminated at the piston. The entire assembly to be so proportioned that regardless of the position of the piston of gap remains between the piston and the cylinder-head penetrated by the piston rod. Means for connecting this gap to the inside of the discharge chamber through a check valve permits gas flow from the discharge chamber to the gap, but no in the reverse direction, and means for venting the gap to the atmosphere. A passage from the opposite side of the piston to the axial outlet of the discharge chamber, a spring or a positive locking device for pressing the poppet against the valve seat.

Abstract: The present invention is a downhole seismic source capable of generating seismic forces in excess of 1000 newtons. The source produces seismic waves for seismic applications, particularly cross borehole measurements and vertical seismic profiling. Coupled with motion sensing devices, the present invention also performs as a seismic logging tool. The source is comprised of an outer housing, a means for clamping the source securely to the wellbore, and a linear electromagnetic actuator which utilizes permanent magnetic material having remanent magnetic field exceeding about 0.9 T such as rare earth permanent magnetics. The source has a diameter of about 12.5 cm to fit within a typical wellbore and the acuator has a length of about 1 meter.

Abstract: An earth impedance determination and compensation system for use with a seismic vibrator utilizes output signals from accelerometers on the baseplate and reaction mass portions of the vibrator to create a signal indicative of the near-surface weathered earth layer impedance below the baseplate. The impedance signal is utilized to generate parameter signals which are indicative of the compressional and shear wave patterns generated by the baseplate and may be used to more rapidly and accurately design seismic source arrays to optimize the wave pattern emanating therefrom. One of the parameter signals is directly indicative of the travel time thickness of the weathered surface layer and may be used to accurately determine the static correction factor attributable solely to weathered layer topography.

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.