Abstract: Controlled-polarization marine seismic shear-wave source has a base suitable for positioning on a seafloor, beneath a water body. Twin water-blast tubes (seismic-impulse-generation thrusters) are mounted on the base, aimed upwardly, outwardly in opposite directions at equal acute angles &bgr; relative to the base. These blast tubes are positioned symmetrically on opposite sides of vertical centerline CL of the source. When submerged, water enters open mouths at upper ends of the tubes. The base has multiple downwardly projecting blade-like teeth for penetrating into the seafloor. Firing a compressed-air discharger mounted in a lower end of a water-blast tube hurls a powerful slug of water upwardly along the tube, producing a powerful reaction impulse acting downwardly generally parallel with the tube axis.

Abstract: An uncomplicated, easy to operate, relatively inexpensive, compact and powerful acoustical source hydro gun for use in a liquid environment is particularly effective in a multiple array for marine life management. The powerful output, compactness and non-complex features of this hydro gun enable its advantageous use as a seismic energy source for high resolution marine seismic exploration and for seismic exploration when lowered down into a well in the earth containing liquid. A cylinder containing a free-moving piston has water discharge ports near one end for admitting water when the hydro gun is immersed in water and for discharging water when the hydro gun is activated by a solenoid valve. The solenoid valve is mounted on a cylinder head block containing a small annular high pressure firing chamber charged with pressurized gas and closed by the solenoid valve.

Abstract: A method and system are provided for well velocity shooting and vertical seismic profiling utilizing mobile seismic land sources for transmitting powerful seismic energy impulses into the earth. A plurality of nesting pairs of tanks are transported on a single vehicle to a well site where the tanks are unloaded and arranged in a suitable array, for example, in a linear array or uniformly spaced around the mouth of the well. The tanks each have a displaceable end portion serving as a diaphragm placed in contact with the ground near the well. Then the tanks are filled with a noncompressible liquid. The total effective mass of the liquid may be increased by adding density-increasing materials thereto. Air guns are suspended in the tanks submerged in the liquid therein. The air guns are fired in a predetermined manner, abruptly releasing pressurized gas into the liquid contained in the tanks for providing powerful seismic impulses which are transmitted into the ground by the displaceable diaphragms.

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 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.