Abstract: An optical fiber sensor array is disclosed which includes a first sensor fiber and a first reference fiber coupled at one end thereof to one side of a first optical coupling. A first wavelength selective reflector is coupled to the other end of each of the first sensor fiber and the first reference fiber. A second sensor fiber is coupled at one end to one side of a second optical coupling. The other side of the second optical coupling is coupled to an opposite side of one of the first wavelength selective reflectors coupled on one side to the first sensor fiber and the first reference fiber. The array also includes a second wavelength selective reflector coupled to the other end of each of the second sensor fiber and the second reference fiber. The second wavelength selective reflectors are operative at a wavelength different from an operative wavelength of the first wavelength selective reflectors.

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 method is disclosed for deghosting seismic data. The data include measurements of a vertical component of particle motion and pressure. The measurements are substantially collocated and made at a plurality of spaced apart positions. The method includes transforming the data into the spatial frequency domain, and separating upgoing and downgoing wavefield components of the transformed data. Water surface multiples may also be removed by decomposing the signals made at a plurality of seismic energy source locations into upgoing and downgoing wavefields.

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 method is disclosed for processing seismic data. The method includes prestack depth migrating the seismic data to generate common image gathers using an initial velocity-depth model. Horizons in the migrated seismic data are selected. Residual migration velocity analysis in the depth-offset domain is performed with respect to each selected horizon, and the velocity-depth model is updated based on the residual migration velocity analysis.

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 method is disclosed for attenuating noise in seismic data. The method includes calculating a trace envelope for at least part of at least one seismic trace, generating a filtered envelope from the trace envelope, and transforming the filtered envelope to a filtered trace. In one embodiment, a length of a filter operator used for generating the filtered envelope is inversely related to a maximum frequency to be preserved in the filtered trace.

Abstract: A set of pre-stack seismic data is downward extrapolated, by first determining a migration interval in the seismic data set. A maximum error criterion is selected for the migration interval. A maximum relative error in phase calculated as a function of frequency, propagation angle, and the relative variation in velocity in the migration interval. The maximum relative error in phase is compared to the maximum error criterion. The type of extrapolation to use in the migration interval is determined from the comparison of the maximum relative error in phase to the maximum error criterion. The type of extrapolation is selected from a set comprising Gazdag phase-shift extrapolation, split-shift Fourier extrapolation, and implicit finite difference extrapolation.

Abstract: A seismic wavefield is extrapolated using variable extrapolation step size and then phase-shifted linear interpolation is applied to the extrapolated wavefield.

Abstract: A method is disclosed for processing seismic data. The method includes determining a position of a seismic energy source and seismic receivers at a time of actuation of the source. A velocity of the seismic receivers with respect to the source position is determined at the time of actuation. An offset of the receivers is corrected using the velocity. A moveout correction is determined for the signals detected by the sensors based on the corrected offset and a velocity of earth media through which seismic energy passed from the source to the sensors.

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: A method is disclosed for determining interval anisotropic parameters. The method includes determining normal moveout (NMO) velocities and effective anelliptical parameters from seismic data traces. The NMO velocities are processed to obtain interval NMO velocities. The NMO velocities, effective anelliptical parameters and interval NMO velocities are inverted to obtain the interval anisotropic parameters. In one embodiment, the inversion includes damped least squares. In one embodiment, the inversion is preconditioned.

Abstract: A method and system for interrogating a seismic sensor in a seismic cable having modular sensing stations spaced along the seismic cable and a connection module head end of the sensor sections, that includes dropping, at the connection modules, a wavelength of light from an input bus telemetry fiber that includes multiple wavelengths of light, distributing the dropped wavelength of light to the seismic sensor, returning the dropped wavelength from the seismic sensor to a return telemetry fiber, remultiplexing the dropped wavelength of light onto the return bus telemetry, and amplifying, in the seismic cable, the returned dropped wavelength.

Abstract: A cable for towing marine devices is disclosed. The cable includes a strength member and at least one conduit associated with the strength member. The conduit has apertures therein at selected locations along the conduit. The apertures are adapted to conduct gas from a source into water in which the cable is disposed. Also disclosed is a method for improving the flow of a cable through water. The method includes releasing a gaseous bubble stream proximate an outer surface of said cable while the water is moving relative to the cable.

Abstract: A method for attaching seismic sensors in a seismic cable that includes a strength member inside a cable jacket with a fiber tube wound around the strength member and a sensor station base attached around the cable wherein the jacket is removed, at least one fiber tube is extracted and a seismic sensor is attached to the fiber tube.

Abstract: In a seismic survey, idealized subsurface illumination is generated using idealized survey data. Then, the following three steps are performed during each of a sequence of time intervals during the seismic survey. First, an incremental portion of actual survey data is collected, using data acquisition equipment at a data acquisition location. Second, the incremental portion of actual survey data is communicated from the data acquisition location to a data processing location. Third, an incremental portion of actual subsurface illumination is generated using the incremental portions of actual survey data, to incrementally generate actual subsurface illumination at the data processing location. It is determined if additional data acquisition is desirable by comparison of the idealized subsurface illumination and the actual subsurface illumination, in the data processing location.

Abstract: A method for seismic surveying is disclosed which includes towing a first seismic energy source and at least one seismic sensor system. A second seismic energy source is towed at a selected distance from the first source. The first seismic energy source and the second seismic energy source are actuated in a plurality of firing sequences. Each of the firing sequences includes firing of the first source, waiting a selected time firing the second source and recording signals generated by the seismic sensor system. The selected time between firing the first source and the second source is varied between successive ones of the firing sequences. The firing times of the first and second source are indexed so as to enable separate identification of seismic events originating from the first source and seismic events originating from the second source in detected seismic signals.

Abstract: A method is disclosed for marine seismic surveying in which a seismic signal is detected in a body of water with a motion sensor and a pressure sensor positioned at a location proximate the bottom of the body of water. Seismic signals are detected with pressure sensors positioned in one or more streamer cables being towed in the body of water near the location proximate the bottom of the water at which a motion sensor and a pressure sensor are positioned. The signals detected by the motion sensor and pressure sensor positioned proximate the bottom of the body of water are used for calibrating the seismic signals detected with the pressure sensors positioned in the streamer cables.

Abstract: A method is disclosed for separating energy resulting from actuating at least two different seismic energy sources from seismic signals. The sources are actuated to provide a variable time delay between successive actuations of a first one and a second one of the sources. The method includes sorting the seismic signals such that events therein resulting from actuations of the first source are substantially coherent in all spatial directions, coherency filtering the first source coherency sorted signals, sorting the seismic signals such that events therein resulting from actuations of the second source are substantially coherent in all spatial directions, and coherency filtering the second source coherency sorted signals.

Abstract: A method of migration of a seismic data is disclosed. The data include a data point having an input source location, an input receiver location, and a scatter point associated therewith. The method includes determining a projected source location, and determining a projected receiver location. The seismic data point is mapped from an input travel time to a projected travel time. A pseudo-offset is determined based on the projected travel time and the data point is mapped to the pseudo-offset.