Abstract: A marine seismic source array includes multiple strings of marine seismic source elements. A first string has a first specified arrangement of air guns between a beginning of the first string and an end of the first string. A second string has a second, different specified arrangement of the air guns between a beginning of the second string and an end of the second string. The second arrangement is the reverse of the first arrangement. A specified arrangement of air guns may be defined, for example, by a number of air guns in each seismic source element, a chamber volume of each air gun, a spacing of the air guns, or any suitable combination of these and other parameters.

Abstract: A seismic air gun includes an operating chamber, a firing chamber, a port, and a longitudinally disposed cavity sized and shaped to accept a plurality of wires. A moveable shuttle includes a shuttle flange within the operating chamber at one end and a firing shuttle flange at the other end proximate the port and firing chamber. The return force urging the shuttle from the unloaded position to the loaded position is independent of the radial thickness of the shuttle and is directly proportionate to the difference between a first and a second radial cross-sectional thickness of the shuttle flange. As a result, the return force can be optimized without any resulting loss of structural integrity to the shuttle, thereby allowing the port to stay open longer and increasing the amplitude of the primary seismic wave. Seals allow the gun to operating without water lubrication.

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: Streamlined, towable, marine seismic energy vibrator for creating intense swept-frequency and pulse-coded seismic signals in a body of water has a sleek, fish-like configuration designed for towing with minimum drag. The vibrator has a streamlined hollow towing head and a streamlined hollow tail head mounted onto front and rear of a long cylindrical tubular wall which is modular, comprising cylinder sections joined in end-to-end axial alignment. Within this long tubular cylinder wall is an axially vibratable multi-piston assembly having a plurality of pistons on a long piston rod. One piston is positioned in each of the cylinder chambers. These chambers hive multiple ports opening out through the long cylindrical wall. An elongated circular cylindrical elastomeric bladder forms a water-filled bladder chamber encircling the wall.

Abstract: For marine seismic surveying using an array of airguns towed behind a survey ship, wherein a common high pressure hoseline supplies compressed air to a multitude of airguns, a method, system and apparatus selectively shut off air flow to any airgun for stopping leakage of compressed air from the common supply line. Shutoff valves are employed with a respective valve being upstream of each airgun to enable selectively shutting off compressed air flow from the common supply line to any airgun for stopping loss of compressed air from the common line caused by leakage from a leaking component downstream from any valve, such as a ruptured feeder hoseline to an airgun. Each shutoff valve has a spring whose spring force biases open its valve. Simultaneous electrical energization of windings in all shutoff valves electromagnetically overcomes the spring force for simultaneously closing all valves.

Abstract: A large-diameter, cylinder-shuttle airgun for seismic uses has a cylinder shuttle configured as a hollow, elongated cylinder body of revolution with an inwardly-facing cylinder guide surface and having two outwardly-extending, axially-spaced annular flanges. These two annular flanges are an operating flange at an upper end of the body of revolution and a firing flange at an intermediate region thereof. A cylinder skirt extends down below the firing flange, and the cylinder shuttle has an overall axial length L. The firing flange has a perimeter of outside diameter OD, and the ratio of L to OD is at least about 1 to 1. A cylinder housing of the airgun has a main inner cylinder structure encircled by the cylinder shuttle. This main inner cylinder structure may have an axial passageway of sufficient diameter for passing at least one compressed air hose and at least one multi-conductor electric cable axially therethrough.

Abstract: An inflatable attenuator having an inflatable resilient bladder enclosed by a perforated protective cylindrical housing is positioned in a liquid column in a well below (and if desired another inflatable attenuator is also positioned above) an impulsive energy source in the liquid column. The housing has an exterior diameter slightly less than the interior diameter of the well. The bladder is inflated when in the liquid column by gas supplied from a pressurized gas container attached to the attenuator or is supplied with pressurized gas through a hose line from a source of pressurized gas located on the surface of the Earth near the mouth of the well. A pressure-regulator responsive to the ambient hydrostatic pressure in the liquid column near the pressure regulator serves to maintain the pressure of the gas within the bladder at a regulated pressure at least equal to the ambient pressure in the liquid column where it is located.

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 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 plurality of submerged control station junction boxes each include a microprocessor having data storage and transmission capability, airgun firing and related electronic circuits to control a predetermined airgun or airgun groups. These junction boxes are towed at spaced positions along an airgun array. An electrical cable and sections of high pressure air supply line are detachably coupled to each junction box. The predetermined airguns to be controlled by a junction box are detachably coupled thereto. Thus, the number of airguns in the towed array can be changed by coupling or uncoupling junction boxes and the associated airguns controlled by them. The junction boxes are automatically cooled on shipboard by increasing low pressure air until a relief valve opens for establishing a continuous cooling flow of low pressure through a protective hose sheath and the junction boxes.

Abstract: An airgun impulsive energy source has an elongated shaft bearing surrounding the shaft of the reciprocatable shuttle for guiding the shuttle and preventing its operating or firing pistons from contacting their respective cylinder walls. The illustrative embodiment of this airgun is proportioned to be self-firing with a fast repitition rate. This airgun has an elongated cylindrical housing with discharge ports in a cylindrical wall positioned between the operating and firing chambers. The shuttle-guiding shaft bearing is positioned in the cylindrical housing between the ports and an operating chamber. This shaft-guiding bearing has a length which is more than 1.

Abstract: A land seismic energy source is provided having a rigid dome-shaped bell containing a substantially imcompressible liquid and an airgun for abruptly releasing pressurized gas into the liquid for generating powerful seismic impulses. The bell has a lower rim with a metal pan positioned below the rim for engaging the surface of the earth below the bell, and it is mounted for upward and downward movement relative to the bell. A resilient, flexible elastomeric diaphragm is mounted on the rim of the bell and extends across the bottom of the bell for retaining the liquid in the bell.

Abstract: A high ambient liquid pressure-resistant electrical connector is shown with an airgun having a solenoid actuated valve mounted on the airgun. A multi-conductor electrical cable is connected by this pressure-resistant connector to a plurality of terminals of the solenoid valve for protecting from ambient liquid the terminals and the adjacent portions of the conductors. This pressure-resistant electrical connector includes a connector housing having an upper end and a lower end, with the lower end of the housing being mounted to the airgun. The connector housing has a fluid sealant chamber for enclosing the electrical terminals and adjacent portions of the conductors connected to the terminals and includes at least one barrier for engaging the cable to protect against ambient liquid seeping past the barrier to the electrical terminals. The connector housing defines a cylindrical space carrying a spring-loaded piston.

Abstract: A seismic source is disclosed which is particularly useful for generating horizontally polarized shear waves in the earth for seismic surveying. It comprises an elongated, hollow, substantially vertical cylinder having an earth-contacting pad pivotally mounted to its lower end by a horizontal pivot shaft extending parallel with the front-to-back centerline of a transport vehicle. The lower surface of this large rigid pad contains multiple, blade-like teeth extending parallel with the pivot shaft for gripping the earth's surface for transmitting powerful horizontally polarized shear stress impulses into the earth. The cylinder contains a slidable piston-like reaction mass. The bottom of the cylinder is a strong upwardly diverging conical surface serving to focus and direct upwardly the discharge blast from each port of an air gun extending horizontally and with the axis of the air gun being oriented parallel with the pivot axis and being located a short distance above the pivot shaft.

Abstract: An air gun is mounted in a reaction mass having an impulse-transmitting ground-contact plate movably mounted below the mass. This mass is in face-to-face contact with the plate over the major portion of the entire upper surface of the contact plate. Confined liquid is not employed. The air gun is charged with pressurized gas and fired, discharging the pressurized gas into the narrow horizontal interface region between reaction mass and plate. Rapid expansion of the discharged gas between mass and plate causes an intensely powerful seismic impulse to be transmitted into the earth. The air gun has a firing chamber for holding a charge of pressurized gas, a movable shuttle for suddenly discharging the pressurized gas, including upper and lower pistons with a hollow member connecting these pistons. A pedestal assembly carrying said shuttle is mounted from above to the reaction mass and extends down into the hollow shuttle member.

Abstract: A plurality of control station, watertight, submerged junction boxes are towed at spaced positions located along an airgun array, each junction box for including a microprocessor and data storage transmission capability, and airgun firing circuits to control predetermined airguns. The electrical cable for the array and the air supply lines, as well as the airguns to be controlled, are detachably coupled to respective junction boxes. Thus, the number of airguns in the towed array can be changed quickly and conveniently by coupling or uncoupling junction boxes and the associated airguns. A protective hose sheath extends between successive junction boxes and this hose sheath contains power lines and a communication bus, detachably connected to terminals in successive junction boxes. This hose sheath and interiors of junction boxes are pressurized with low pressure air during towing for excluding water in the event of a leak.

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 sleeve shuttle air gun is described which can be fired by a solenoid valve without dumping compressed air into the ambient prior to firing, thereby avoiding the generation of premature impulses caused by such dumping and avoiding the heavy duty complex solenoid dump valves and two-stage dump valves of the prior art. The sleeve shuttle is automatically returned to its initial closed and sealed position after each firing of the airgun by the refilling flow of only one level of pressurized air without a separate low level pressure source to control the sleeve shuttle. A long acceleration path is provided so the sleeve shuttle attains velocity prior to opening the discharge ports for producing a sudden, powerful discharge. The end of the sleeve shuttle travels completely beyond the discharge ports, and is then damped by interaction with damper ports located beyond the discharge ports.

Abstract: A massive piston that does not strike anything during operation reciprocates with bouncing action up and down within a cylinder. An annular pressurized gas storage chamber encircles the piston and travels up and down with it. Pressurized gas is continuously supplied into this movable chamber to be temporarily stored therein. As the piston descends toward the lower end of the cylinder, pressurized gas from this travelling chamber is automatically suddenly allowed to bypass the lower portion of the piston, thereby injecting the pressurized gas into a bounce chamber between the descending piston and a bottom assembly. When this pressurized gas rushes through the bypass, it forces an exhaust valve closed.

Abstract: A massive piston, which might be called a "ram", except that it does not strike anything during operation, reciprocates with bouncing action up and down within a cylinder. An annular pressurized gas storage chamber encircles the piston and travels up and down with it. Pressurized gas is continuously supplied into this movable chamber to be temporarily stored therein. As the piston descends toward the lower end of the cylinder, pressurized gas from this travelling chamber is automatically suddenly allowed to bypass the lower portion of the piston, thereby injecting the pressurized gas into a bounce chamber between the descending piston and a bottom assembly. When this pressurized gas rushes through the bypass, it forces an exhaust valve closed.