Abstract: A system for retrieving a device from the bottom of a body of water includes a clamp configured to be slidably affixed to the device above the water bottom. The clamp has a selectively engageable lock to fix a position of the clamp on the device. A line ratchet is coupled to the clamp. A line is disposed through the line ratchet. A first flotation device is coupled to one end of the line. A second flotation device is coupled to the other end of the line. The system includes means for applying tension to the line disposed proximate the second flotation device. The line ratchet is arranged to enable movement of the line therethrough toward the means for applying tension, and is also arranged to substantially prevent motion therethrough in the opposite direction.

Abstract: Remote seismic surveying systems and methods are disclosed. At least some embodiments illuminate a water or ground surface with a beam from a coherent electromagnetic wave source. Reflected electromagnetic energy is focused onto an image plane where it combines with a reference beam to form an interference pattern. Electronics track the intensity versus time for multiple points in the image and derive displacement signals for various physical locations in the survey region. These displacement signals are associated with seismic source firing times and locations before being stored as seismic traces in a survey database. Some variations use the reflected electromagnetic energy to create multiple interference patterns that vary due to different path length differences, thereby eliminating signal phase ambiguities.

Abstract: A synchronization system for a nodal geophysical data recorder includes an electromagnetic transmitter associated with a master recording unit. The master unit includes devices for determining time and geodetic position from an external reference. The transmitter includes a code generator to cause transmission of a time synchronization signal as a coded sequence. The transmitter is configured to induce an electromagnetic field in at least one of subsurface rock formations and a body of water. At least one nodal geophysical data recorder includes at least one geophysical data sensor. The at least one sensor has measurements therefrom stored in a data storage device associated with the recorder wherein the recorder includes a clock for time indexing the stored data measurements. The recorder includes a receiver for detecting and decoding the time synchronization signal in the coded sequence to synchronize the clock with the synchronization signal.

Abstract: A method for correcting time error in an oscillator operated clock according to one aspect of the invention includes at selected times determining at least one of a time error in the clock and a frequency difference between the oscillator and a reference oscillator by detecting a time reference signal. A change in the at least one of the time error and the frequency difference between a first one and a second one of the detecting the time reference signals is determined. A frequency of the oscillator is adjusted so as to substantially cancel a cumulative time error between the second one of the detecting the time reference signal and a selected detecting the time reference signal.

Abstract: A seismic energy source includes at least a first and a second acoustic radiator operatively coupled to a non-linear medium proximate an upper limit of formations in the Earth's subsurface. The first and second acoustic radiators are configured to convert electrical energy directly into acoustic energy. The source includes means for operating the first and the second acoustic radiator at respective first and second frequencies. The first and second frequencies are selected such that substantially no acoustic energy propagates through the non-linear medium. The first and the second frequencies are selected such that a difference therebetween is swept through a range of frequencies of seismic energy capable of propagating through the Earth's subsurface to at least one acoustic impedance boundary within the Earth's subsurface.

Abstract: A system for retrieving a device from the bottom of a body of water includes a clamp configured to be slidably affixed to the device above the water bottom. The clamp has a selectively engageable lock to fix a position of the clamp on the device. A line ratchet is coupled to the clamp. A line is disposed through the line ratchet. A first flotation device is coupled to one end of the line. A second flotation device is coupled to the other end of the line. The system includes means for applying tension to the line disposed proximate the second flotation device. The line ratchet is arranged to enable movement of the line therethrough toward the means for applying tension, and is also arranged to substantially prevent motion therethrough in the opposite direction.

Abstract: Remote seismic surveying systems and methods are disclosed. At least some embodiments illuminate a water or ground surface with a beam from a coherent electromagnetic wave source. Reflected electromagnetic energy is focused onto an image plane where it combines with a reference beam to form an interference pattern. Electronics track the intensity versus time for multiple points in the image and derive displacement signals for various physical locations in the survey region. These displacement signals are associated with seismic source firing times and locations before being stored as seismic traces in a survey database. Some variations use the reflected electromagnetic energy to create multiple interference patterns that vary due to different path length differences, thereby eliminating signal phase ambiguities.

Abstract: An antenna mast system includes an antenna mast and a plurality of circumferentially spaced apart upper cable tensioning arms each coupled at one end proximate the top of the mast. A plurality of circumferentially spaced apart lower cable tensioning arms are each coupled at one end to the mast at a selected distance below the upper cable tensioning arms. A plurality of stay cables are each coupled at one end to one of the upper cable tensioning arms and at the other end to an anchor affixed to the ground. The stay cables are each coupled to a respective one of the lower tensioning arms. The system includes means for tensioning the stay cables.

Abstract: An antenna mast system includes an antenna mast and a plurality of circumferentially spaced apart upper cable tensioning arms each coupled at one end proximate the top of the mast. A plurality of circumferentially spaced apart lower cable tensioning arms are each coupled at one end to the mast at a selected distance below the upper cable tensioning arms. A plurality of stay cables are each coupled at one end to one of the upper cable tensioning arms and at the other end to an anchor affixed to the ground. The stay cables are each coupled to a respective one of the lower tensioning arms. The system includes means for tensioning the stay cables.

Abstract: A method for correcting time error in an oscillator operated clock according to one aspect of the invention includes at selected times determining at least one of a time error in the clock and a frequency difference between the oscillator and a reference oscillator by detecting a time reference signal. A change in the at least one of the time error and the frequency difference between a first one and a second one of the detecting the time reference signals is determined. A frequency of the oscillator is adjusted so as to substantially cancel a cumulative time error between the second one of the detecting the time reference signal and a selected detecting the time reference signal.

Abstract: A seismic energy source includes at least a first and a second acoustic radiator operatively coupled to a non-linear medium proximate an upper limit of formations in the Earth's subsurface. The first and second acoustic radiators are configured to convert electrical energy directly into acoustic energy. The source includes means for operating the first and the second acoustic radiator at respective first and second frequencies. The first and second frequencies are selected such that substantially no acoustic energy propagates through the non-linear medium. The first and the second frequencies are selected such that a difference therebetween is swept through a range of frequencies of seismic energy capable of propagating through the Earth's subsurface to at least one acoustic impedance boundary within the Earth's subsurface.

Abstract: A connector for a seismic data acquisition cable includes a molded plastic connector body. The connector body has inserted therein at least one electrical contact for mating with a corresponding electrical contact. The connector body has an internal opening for receiving an electrical cable. The connector body has a mating surface adapted to contact a corresponding connected structure. The internal opening is filled with a curable compound which upon cure forms a substantially interface free bond with the connector body and an external jacket of the electrical cable.

Abstract: A seismic sensor includes a housing having a device for releasably affixing the housing to the Earth. A seismic sensing element is disposed within the housing. A wireless signal communication device is associated with the housing and is in signal communication with the seismic sensing element. The communication device is in signal communication with a seismic data recording unit.

Abstract: Systems and methods are disclosed to construct subsurface images from diffuse seismic energy. Various disclosed system embodiments include multiple seismic sensors that each convert received seismic energy into one or more seismic signals. One or more processor combine the seismic signals to determine a subsurface map. As part of determining the map, the processor(s) systematically focus the array of seismic sensors on each bin in the subsurface volume of interest. In this manner each bin becomes a focal point of the array. For each bin, the processor(s) analyze the seismic wave travel time to each seismic sensor and apply a corresponding time shift to align the seismic signals with a uniform travel time. The time-shifted seismic signals are then combined to determine an intensity value for seismic energy radiating from the focal point. A subsurface map can then be derived from the intensity value as a function of position.

Abstract: A seismic sensor cable is disclosed. The cable includes an outer jacket disposed on an exterior of the cable. The outer jacket excludes fluid from entering an interior of the cable. A reinforcing layer disposed within the outer jacket, which includes at least one electrical conductor disposed therein. An inner jacket is disposed within the reinforcing layer, and at least one electrical conductor disposed within an interior of the inner jacket. Some embodiments include at least one seismic sensor electrically coupled to the at least one electrical conductor disposed in the reinforcing layer In some embodiments a housing is disposed over the electrical coupling of the sensor to the conductor. The housing is molded from a polyurethane composition adapted to form a substantially interface-free bond with the cable jacket when the polyurethane cures.

Abstract: A seismic sensor cable is disclosed. The cable includes an outer jacket disposed on an exterior of the cable. The outer jacket excludes fluid from entering an interior of the cable. A reinforcing layer disposed within the outer jacket, which includes at least one electrical conductor disposed therein. An inner jacket is disposed within the reinforcing layer, and at least one electrical conductor disposed within an interior of the inner jacket. Some embodiments include at least one seismic sensor electrically coupled to the at least one electrical conductor disposed in the reinforcing layer In some embodiments a housing is disposed over the electrical coupling of the sensor to the conductor. The housing is molded from a polyurethane composition adapted to form a substantially interface-free bond with the cable jacket when the polyurethane cures.

Abstract: A seismic sensor cable is disclosed. The cable includes an outer jacket disposed on an exterior of the cable. The outer jacket excludes fluid from entering an interior of the cable. A reinforcing layer disposed within the outer jacket, which includes at least one electrical conductor disposed therein. An inner jacket is disposed within the reinforcing layer, and at least one electrical conductor disposed within an interior of the inner jacket. Some embodiments include at least one seismic sensor electrically coupled to the at least one electrical conductor disposed in the reinforcing layer In some embodiments a housing is disposed over the electrical coupling of the sensor to the conductor. The housing is molded from a polyurethane composition adapted to form a substantially interface-free bond with the cable jacket when the polyurethane cures.

Abstract: A system or apparatus and method for retrieving cable from water during marine operations is provided that reduces damage to the cable from pulling forces during the retrieval. A pulling device distributes the forces and stresses all along the cable components. In one embodiment, the pulling drive comprises a pulling drum powered by a clutching system or by a hydraulic torque conversion system set to slip or stall at a selectable force value. The apparatus may use a see-saw action to maintain the forces below damaging levels. The system may be adapted for deploying cable in marine operations as well.

Abstract: There is provided an apparatus and vehicle for laying seismic line cable on the ground, retrieving the cable from near the ground surface, and transporting the cable. The vehicle carries at least one cable reel for unspooling the cable therefrom when laying cable and spooling the cable thereon when retrieving the cable. When laying cable, a towed depression wheel forms a depression wheel forms a channel in the ground for laying the unspooled cable therein. The cable reel includes an electric slip ring for electrically energizing and testing the cable components while the cable is being laid. When used in very cold environments, a temperature controlled enclosure encloses the cable reel for maintaining the cable at a temperature at which it is sufficiently flexible for handling and laying. When retrieving cable, a motor power controller automatically controls the power to the cable reel drive motor for maintaining constant tension in the cable being retrieved.

Abstract: There is provided an appartus and vehicle (10) for laying seismic line cable (12) on the ground, retrieving the cable from near the ground surface, and transporting the cable. The vehicle (10) carries at least one cable reel (14, 15) for unspooling the cable therefrom when laying cable and spooling the cable thereon when retrieving the cable. When laying cable (12), a towed depression wheel forms a depression wheel (16) forms a channel in the ground for laying the unspooled cable therein. The cable reel (14, 15) includes an electric slip ring for electrically energizing and testing the cable components while the cable is being laid. When used in very cold environments, a temperature controlled enclosure (22) encloses the cable reel (14, 15) for maintaining the cable at a temperature at which it is sufficiently flexible for handling and laying.