Abstract: An electromagnetic survey sensing device includes at least two electrodes disposed at spaced apart locations. An electrical to optical converter is electrically coupled to the at least two electrodes. The converter is configured to change a property of light from a source in response to voltage imparted across the at least two electrodes. The device includes an optical fiber optically coupled to an output of the electrical to optical converter, the optical fiber in optical communication with a detector.

Abstract: A nodal geophysical recorder includes a housing, at least one geophysical sensor disposed within the housing and a recording device for recording signals detected by the at least one geophysical sensor. A navigation device is configured to determine a path between an initial geodetic position of the housing and a selected geodetic position on the bottom of a body of water. At least one deflector is in signal communication with the navigation device and is configured to cause the housing to move along the determined path after the housing is released into the body of water from the initial position.

Abstract: A method for operating a geophysical sensor streamer in body of water includes operating a remotely operated vehicle coupled to a forward end of the streamer to tow the streamer in the water. Signals generate by sensors on the streamer are communicated substantially in real time to a recording unit on a survey vessel using at least one of electrical and optical cables in an umbilical cable connecting the remotely operable vehicle to the survey vessel.

Abstract: A method for controlling output of a marine seismic vibrator includes operating the vibrator using a predetermined driver signal. A vibrator output signal is measured at at least two different places on the vibrator. The at least two measured vibrator output signals are used to determine a corrected driver signal, wherein the corrected driver signal results in fewer harmonics of fundamental frequencies in the vibrator output. The vibrator is operated using the corrected driver signal.

Abstract: A marine seismic streamer includes a jacket substantially covering an exterior of the streamer. At least one strength member is disposed along the length of the jacket. A sensor mount is coupled to the strength member. At least one particle motion sensor is suspended within the sensor mount at a selected location along the jacket. The at least one particle motion sensor is suspended in the jacket by at least one biasing device. A mass of the particle motion sensor and a force rate of the biasing device are selected such that a resonant frequency of the particle motion sensor within the sensor jacket is within a predetermined range. The sensor mount is configured such that motion of the jacket, the sensor mount and the strength member is substantially isolated from the particle motion sensor.

Abstract: An electromagnetic survey sensing device includes at least two electrodes disposed at spaced apart locations. An electrical to optical converter is electrically coupled to the at least two electrodes. The converter is configured to change a property of light from a source in response to voltage imparted across the at least two electrodes. The device includes an optical fiber optically coupled to an output of the electrical to optical converter, the optical fiber in optical communication with a detector.

Abstract: A method for marine seismic surveying includes towing a streamer in a body of water. The streamer includes a plurality of spaced apart sensor groups, each including a plurality of longitudinally spaced apart pressure sensors and particle motion responsive sensors. Signals are detected at each of the sensors in response to actuation of a seismic energy source. Components of the sampled motion signals in each group above a selected frequency are combined to generate respective group motion signals. Components of the motion responsive signals below the selected frequency are velocity filtered. The velocity filtered signals are combined with the group motion signals to generate full bandwidth motion responsive signals corresponding to each sensor group.

Abstract: A method for generating seismic energy for subsurface surveying include operating a first seismic vibrator above an area of the subsurface to be surveyed and operating at least a second seismic vibrator above the area substantially contemporaneously with the operating the first seismic vibrator. The first and the second vibrators each have a different selected frequency response. The first and second vibrators each is operated by a same direct sequence spread spectrum signal, wherein a different number of modulation operations for each logical value in the direct sequence spread spectrum signal is selected for each vibrator.

Abstract: A seismic vibrator includes a transducer, a reactive mass, a base plate to couple motion of the reactive mass to subsurface formations and a linkage system configured to couple motion of the transducer to the reactive mass and the base plate. The linkage system cooperates with the reactive mass and the transducer to define a first resonant frequency and a second resonant frequency within a range of 1 to 300 Hz.

Abstract: A method for controlling output of a marine seismic vibrator includes operating the vibrator using a predetermined driver signal. A vibrator output signal is measured at at least two different places on the vibrator. The at least two measured vibrator output signals are used to determine a corrected driver signal, wherein the corrected driver signal results in fewer harmonics of fundamental frequencies in the vibrator output. The vibrator is operated using the corrected driver signal.

Abstract: A seismic survey system includes at least one autonomously operated vehicle and at least one seismic energy source associated with the autonomously operated vehicle. The autonomously operated vehicle includes a controller programmed to operate the at least one seismic energy source at selected times and to cause the autonomously operated vehicle to follow a predetermined geodetic path.

Abstract: A receiver streamer system for marine electromagnetic surveying includes a first streamer, and a second streamer disposed substantially parallel to and spaced apart from the first streamer. A first pair of electrodes is associated with the first streamer and a second pair of electrodes is associated with the second streamer. Each of the first and second pairs of electrodes is functionally associated with a voltage measuring circuit configured to measure voltage along an inline direction. At least one electrode on each of the first and second streamers is configured and associated with a voltage measuring circuit to make voltage measurements in a cross-line direction.

Abstract: A detector for a marine electromagnetic survey system includes a housing arranged to minimize turbulence when the housing is towed through a body of water, and to minimize motion of the housing in any direction other than the tow direction. The housing includes at least one of an electric field and a magnetic field sensing element associated therewith.

Abstract: A method for generating seismic energy for subsurface surveying includes operating a first seismic vibrator and operating at least a second seismic vibrator substantially contemporaneously with the operating the first seismic vibrator. A driver signal to each of the first and the at least a second seismic vibrators that are substantially uncorrelated with each other.

Abstract: A method for generating seismic energy for subsurface surveying includes operating a first seismic vibrator and operating at least a second seismic vibrator in a body of water substantially contemporaneously with the operating the first seismic vibrator. Each vibrator has a different selected frequency response, and the vibrators each are operated at a depth in the water such that a surface ghost amplifies a downward output of each vibrator within a selected frequency range. A signal used to drive each vibrator has a frequency range corresponding to the frequency range of each vibrator.

Abstract: Signals of pressure sensors and particle motion sensors located in marine seismic streamers are combined to generate a seismic wavefield. At least a part of the particle motion sensor signal is calculated from a recorded pressure signal and the calculated at least a part of the particle motion sensor signal is used to generate a particle motion sensor signal in which noise is substantially attenuated in at least a lower frequency range thereof. The pressure sensor data and the noise attenuated particle motion sensor signal can then be combined to calculate up- and down-going wavefields.

Abstract: A merged particle velocity signal is generated by combining a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by cross-ghosting analysis, with a simulated particle velocity signal, calculated in a lower frequency range from a recorded pressure signal using a time-varying filter based on the time-dependent arrival angle. Combined pressure and vertical particle velocity signals are generated from the recorded pressure and merged particle velocity signals.

Abstract: Systems and methods for marine surveying of strata beneath a seafloor are disclosed, including, in certain aspects, systems employing one or more cables with a plurality of opto-electrical detector electrodes and an electrical wire with a fixed reference potential imposed thereon along the cable length. In a multi-cable system, the same fixed reference potential is applied to all wires in all cables. This abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure and is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims, 37 C.F.R. 1.72(b).

Abstract: A seismic vibrator includes a transducer, a reactive mass, a base plate to couple motion of the reactive mass to subsurface formations and a linkage system configured to couple motion of the transducer to the reactive mass and the base plate. The linkage system cooperates with the reactive mass and the transducer to define a first resonant frequency and a second resonant frequency within a range of 1 to 300 Hz.

Abstract: A method for detection of hydrocarbon bearing formations below the bottom of a body of water from seismic signals includes moving a plurality of spatially distributed seismic sensors in a body of water and detecting seismic signals including response to any seismic energy having frequencies down to proximate zero. The method includes stacking the acquired seismic signals from the plurality of the sensors in both longitudinal and transverse directions with respect to motion of the sensors in the body water. The stacked signals are analyzed for presence of passive seismic energy indicative of hydrocarbon bearing formations below the bottom of the body of water.