Western Geophysical Company of America

Other

John Lloyd Paitson

Carl H Savit

Otis A Johnston

Clifford E Anderson

Charles W Dick

Marion Lonnie Parker

Robert N Hendley

Apparatus for controlling a release of pressurized fluid, to generate an acoustic or shock wave impulse for use in underwater reflection seismic surveys. Compressed air is supplied to the acoustic impulse generator and is used both to provide the compressed air acoustic impulse and to retain two piston members in sealing engagement with each other to maintain the compressed air within the apparatus. The two internal pistons are hollow, open-ended cylindrical members, and are adapted to slide axially within a cylindrical chamber and abutt one another to preclude escape of compressed air. To fine the acoustic impulse generator, compressed air pressure holding the first piston member in position over a series of exhaust ports is suddenly reduced, causing that piston to shift within its chamber, exposing the ports to atmosphere and thereby emitting an acoustic impulse of compressed air. Immediately thereafter, residual air pressure within the device causes the second piston to shift in the same direction following the first piston to again close the exhaust ports and preclude further escape of compressed gas, thus defining an acoustic impulse of finite duration.

Acoustic impulse generator

An air actuated seismic signal generator, commonly termed an air gun includes a cylindrical casing that is divided into a control chamber and a firing chamber by a sliding valve. The end face of the sliding valve that is exposed to the control chamber has a greater area than the end face exposed to the firing chamber. An air exhaust port is provided in the firing chamber; the exhaust port may be opened or closed by sliding the valve away from or towards a seat that is associated with the exhaust port. Air is admitted to the control chamber at a relatively low pressure of about 500 psi, and holds the valve in the exhaust-port-closed position because of the differential forces on the valve end faces. The firing chamber is pressurized to a relatively high pressure of about 5000 psi by a separate air supply. There is no air communication or equalization between control and firing chambers. When some of the air in the control chamber is dumped, the differential forces are upset and the sliding valve moves away from the exhaust port seat, to impulsively release the air in the firing chamber. As the piston moves away from the seat, it momentarily compresses the air remaining in the control chamber. The compressed air acts like a spring, absorbs the motion of the valve and bounces the valve back towards the exhaust port seat. At the same time a fresh supply of control air is admitted to the control chamber to finally push the valve closed again. The amount of air remaining in the control chamber and hence the 'resiliency' of the air spring can be set by means of calibrated orifices in the air dump line.

Pneumatic seismic signal generator with independent firing control

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. The pulse repetition rate, that is the frequency of the pulse train, depends on the throttle valve setting and/or the tension of the exhaust valve load spring.

Rapid fire air gun

An apparatus for generating a series of seismic acoustic pulses in a body of water. The series is characterized by having continuously-variable, non-repetitive time intervals between successive pulses during a continuous seismic recording. The preferred generator is an air gun comprising a variable-speed motor with a rotating cam for actuating a sleeve valve which alternately opens and closes exhaust ports in a high-pressure chamber. As the valve repeatedly opens, jets of high-pressure air are impulsively expelled into the surrounding water, thereby generating an underwater acoustic pulse train.

Marine acoustic pulse train signal generator

A seismic exploration system for use on ice-covered waters is disclosed. The system comprises a housing which contains equipment such as an engine, a compressor, means for boring holes in the ice, and acoustic signal generating means that can be lowered into the water through holes in the ice. The housing is sufficiently lightweight that it easily can be transported from one location to another by helicopter or other aircraft. The heat generated by the engine is sufficient to provide a comfortable working environment for personnel within said housing and helps prevent freezing of equipment located within said housing.

Air transportable seismic exploration system for use on ice-covered

A depth controller whose streamlined body has only negative variable lift-producing means, such as a pair of vanes that can produce a controllable downward force. Embodied in the controller are also means providing an uncontrollable upward force. The vanes are preferably movable by translation or rotation in a single plane, inclined relative to the horizontal. Depth control means are operatively coupled to retract the vanes inward as the controller moves from the water surface down to a reference depth. The uncontrollable positive lift producing means return the controller to the desired depth should it fall below the reference depth. Each controller can be used to effectively maintain a seismic streamer cable section at or near the desired reference depth.

Depth controllers with controllable negative and uncontrollable positive

A spar buoy is dynamically stabilized by providing a streamlined, V-shaped wing just above the center of gravity of the spar. The wing has a dihedral sufficient to stabilize the spar in three axes while under tow. The buoy may be equipped with a radio transmitter and a flasher beacon for tracking by an automatic direction finder.

Growing community of inventors

Galveston, TX, United States of America

John Lloyd Paitson