Abstract: A seismic energy generating assembly includes a seismic energy generator positioned within a cage-like frame and adapted for vertical movement within the frame in reaction to the powerful seismic energy impulses that are transmitted downwardly into the earth. The assembly further includes hydraulic catch cylinders for easing the seismic energy generator back down to the ground within the frame after each impulse is generated. Horizontal extensions from this frame ride in guides formed by tubular channels for guiding the entire seismic energy generating assembly when lifted up from the ground by hydraulic lifting cylinders so that the assembly can be readily moved from place to place during seismic exploration. The tubular channels are pivotally mounted to an outer supporting frame on a land vehicle.

Abstract: A variable reluctance type firing sensor is mounted on an air gun for providing an electrical signal indicative of the instant of firing of the air gun. The firing sensor has a magnetic circuit which includes a permanent magnet, a pair of pole pieces and an armature including magnetically permeable material and which is free of mechanical restraint in its normal operating position, being held by magnetic attraction in position in the magnetic circuit. The armature freely "floats" on its "magnetic springs" within a thin walled chamber in which it is housed between the pole pieces, assuming a predetermined position of least magnetic reluctance. The armature which is acceleration-responsive is suddenly displaced from its predetermined position upon the firing of the air gun, and thus the reluctance of the magnetic circuit abruptly increases at the instant of firing.

Abstract: An air gun firing sensor apparatus and system are provided for determining the instant of firing of an air gun by sensing pressure changes within the air gun when it is being fired. A pressure-change-sensitive transducer assembly is inserted into a socket in the housing of a solenoid-controlled valve of an air gun with a passage from the air gun communicating with the transducer for transmitting to the transducer a pressure surge occurring within the air gun whenever it is fired. The transducer assembly has a cylindrical casing with a head mounted at one end. The head includes a plurality of spaced recesses which are adapted to communicate with the passage leading from the air gun.

Abstract: Airgun apparatus are disclosed providing high strength, high pressure and large volume capabilities. An integral high-strength cylindrical housing extends for the full length of the airgun and gives a sleek overall cylindrical configuration. The components of the airgun advantageously are assembled within this cylindrical housing in two groups by sliding them in through the upper or lower end, respectively; moreover, either of the groups of components can be removed independently of the other. The components are pressed firmly together in place within the cylindrical housing by a strong screw-jack type of holding action, and tightening and locking apparatus is included on the airgun itself for enabling the mechanic to tighten and lock the holding means with enormous mechanical advantage.

Abstract: A high strength submersible electrical cable and connector assembly are described which are particularly suitable for use with high pressure valve actuated devices such as air guns which operate in harsh environments such as at sea and which generate large vibrational forces and where the cable and connector are subject to towing stresses as the air gun is towed through the water during a seismic survey operation. The connector has a sleeve body member with a socket retainer in one end adapted to be coupled to a solenoid valve on the air gun. A non-conductive anchor plug is mounted within the sleeve body and mechanically and electrically secures in the sleeve an electrical cable having a plurality of insulated high tensile strength electrical conductors.

Abstract: Firing of a seismic source of the type called an air gun is detected by means of a fluid pressure sensor located in the housing of a solenoid actuated control valve. Through a pressurized gas support port the pressure sensor is in fluid contact with a shuttle-operating chamber of the air gun, and the sensor detects a surge in fluid pressure resulting from rapid motion of the shuttle. if a misfire or malfunction of the air gun is detected by means of the fluid pressure sensor, the malfunctioning air gun can be shut down by actuating the solenoid valve, which is a novel dual action solenoid valve, thereby preventing pressurized gas from being supplied to that particular air gun. The valve includes a valve stem with radial gas inlet ports and radial triggering ports. A solenoid plunger is movable to close one or the other of the sets of ports.

Abstract: A powerful seismic impulse is generated in a body of water by a slug of water propelled from a seismic source by expanding pressurized gas, but the gas is retained in the source for use in subsequent firings. The seismic energy source, which is called a "hydro gun", is recharged by pumping an incompressible liquid, preferably, water, at high pressure into the gun to compress the retained pressurized gas. The hydro gun includes a firing cylinder, and a piston follower in the firing cylinder divides it into a liquid-charge chamber and a gas-propulsion chamber. The liquid-charge chamber is closed from liquid discharge ports by a shuttle which is held closed by the high pressure of gas in an operating chamber. By pumping an incompressible liquid into the liquid-charge chamber, the follower is forced to compress the pressurized gas which is trapped in the gas-propulsion chamber.

Abstract: Firing of a seismic source of the type called an air gun is detected by means of a fluid pressure sensor transducer in fluid communication with a shuttle-operating chamber of the air gun, and this sensor detects a surge in pressure in a portion of this chamber resulting from rapid motion of the shuttle, thereby producing an electrical signal which provides an accurate indication of the actual time of firing called the "shot instant" of the air gun. The reaction time between the electrical firing command signal and the shot instant is not the same for all air guns in a seismic survey array but may differ from one to another due to variations in the solenoid-actuated valves which trigger the air gun, in tolerances of the air gun parts, frictional effects and slight differences in mass of moving parts, and wear of parts. The method and apparatus as disclosed enables a geophysical survey crew accurately to determine the reaction time of each individual air gun seismic energy source.

Abstract: A seismic land source for transmitting powerful seismic energy impulses into the earth comprising a dome-shaped bell within which is contained a substantially incompressible liquid and an air gun which can be fired for abruptly releasing pressurized gas into the liquid in the bell. A metal pan is positioned below the rim of the bell for engaging the surface of the earth below the bell and is mounted for downward movement with respect to the bell. A flexible elastomeric diaphragm extends across the bottom of the bell above the metal pan and extends upwardly beyond the bell rim between the rim and the pan. The diaphragm has a rounded shoulder portion with an upturned peripheral side wall portion extending upwardly around the exterior of the bell to an elevated level substantially above the bell rim, and the upper edge of the peripheral side wall of the diaphragm is clamped at said elevated level to a flange fixed to the outer surface of the bell.

Abstract: A method and apparatus for simultaneously towing and handling multiple airguns are disclosed for use in marine seismic surveying which provide for ease in handling large numbers of airguns and enable them to stream out at a desired depth behind a submerged towing head in a long flexible streamer, or a plurality of simultaneously towed airgun streamers, whose level below the surface can be changed, if desired, while the survey is progressing. A plurality of airguns are included in each streamer extending for a length behind the survey vessel for providing an effective geographic diversity in the location of the airguns which can be simultaneously fired, or can be fired with time delay, for generating very powerful large area seismic energy wavefronts travelling down through the body of water. The buoyancy of the airgun streamer is controllable to provide neutral buoyancy during towing, if desired, and slight positive buoyancy to float the streamer in preparation for taking it on board the towing vessel.

Abstract: Improved pressurized gas discharging apparatus for use as a down-bore seismic impulse source provides a compact, efficient axially stacked assembly of components within a one piece elongated tubular shell housing having removable end closures. Within the tubular housing, removable partition means define a charge chamber and an operating chamber having an operating shuttle release means therebetween for sudden release of high pressure gas present in the charge chamber through a discharge port into the surrounding environment. Gas flow passageways for the supply of high pressure gas to the chambers extend longitudinally within the wall of the tubular housing and communicate with passages in the partition means. The shuttle release means may be actuated by a solenoid valve also removably positioned within the tubular housing for controlling gas flow through passageways also located within the walls of the tubular housing and within the partition means.

Abstract: A very powerful pile driver is disclosed capable of operation in the air, partially submerged or totally submerged in the ocean for driving long piles into the ocean floor in deep water construction jobs. The pile driver includes a cylindrical housing, a movable massive weight within the housing, an annular cylindrical thrust-transferring member defining a discharge chamber below this weight, and a movable driving head attached to this annular member, forming a thrust-transmitting assembly adapted to be engaged with the pile. Pressurized gas such as compressed air is discharged from gas discharge apparatus, called an airgun located within the discharge chamber and provides two driving thrusts for each discharge.