Abstract: Time slices of seismic data are transformed from rectangular space-time domain to cylindrical space-time domain. 2-D seismic migration is performed on the transformed data for each radial direction. Slices of the migrated data are inverse transformed back to the rectangular space-time domain, generated migrated 3-D data for generally inhomogeneous media.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer, at least one strength member extending along the length of and disposed inside the jacket, at least one seismic sensor mounted in a sensor spacer affixed to the at least one strength member, and a void filler made from a material introduced into the jacket in liquid form and undergoing state change thereafter. The jacket includes an inner layer in contact with and having adhesiveness to the void filler, and an outer layer disposed over the outer layer and having substantially no adhesiveness.

Abstract: In one embodiment the invention comprises a system for planning a seismic survey based on a model of a subsurface formation in which a computer simulation is generated having sources and receivers positioned in selected locations with respect to the model. Ray tracing is performed from the sources to estimate a propagation ray path of seismic signals emanating from the source locations, and emergent points are determined at which ray paths reach the earth's surface following reflection from a subsurface area of interest. A survey may then be designed and performed in which receiver positions are concentrated at the areas where the emergent points are concentrated.

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 method for attenuating multiple reflections in seismic signals includes coherency filtering the seismic signals. The seismic signals are low pass filtered and high pass filtered seismic signals at a frequency selected such that substantially only multiple reflections exist in the seismic signals above the frequency. A mask is generated having unity value where the high pass filtered signal amplitude exceeds a selected threshold. The mask has unity zero value for all other filtered signals. The mask value is multiplied by the low pass filtered signals. The multiplied signals are added to the high pass filtered signals and a coherency filter is applied to remove remaining primary energy to generate a model of the multiple reflections. The multiple reflection model is subtracted from the coherency filtered seismic signals.

Abstract: A method for reducing motion induced voltage in marine electromagnetic measurements includes measuring an electromagnetic field parameter at at least one position along a sensor cable towed through a body of water. Motion of the sensor cable is measured at at least one position along the cable; Voltage induced in the cable is estimated from the motion measurements. The measured electromagnetic field parameter is corrected using the estimated voltages.

Abstract: Diagonal gather trace interpolation systems and methods are disclosed. In some embodiments, the method includes obtaining seismic traces from a marine seismic survey performed using typically two seismic sources fired in a flip-flop pattern. The seismic traces are processed in common field file trace groups from each cable by performing trace interpolation in opposing diagonal directions. Among other things, diagonal trace interpolation may improve azimuthal regularization. In any event, the disclosed interpolation methods maintain spatial bandwidth increased spatial resolution with increased inline and crossline sampling components. Diagonal gather trace interpolation exploits reduced input trace separation to provide improved stability and detection of a greater range of formation dip angles. After interpolation and regularization, the seismic traces may be imaged and interpreted for improved seismic exploration and monitoring.

Abstract: A method for estimating seismic velocities in vertically transversely isotropic media includes generating an initial estimate of vertical interval velocity and interval normal moveout velocity with respect to depth from seismic data. An initial estimate is generated of a first anisotropy parameter with respect to depth. The first anisotropy parameter is related to the interval normal moveout velocity and the interval vertical velocity. An initial estimate is generated with respect to depth of a second anisotropy parameter. The second anisotropy parameter is related to the first anisotropy parameter and an interval anelliptic parameter. A first tomographic inversion is performed with respect to the interval normal moveout velocity and the second anisotropy parameter at a constant value of the first anisotropy parameter until travel time differentials reach minimum values. Layer depths are adjusted with the initial estimate of vertical interval velocity.

Abstract: Marine towed streamer seismic data are combined from a first survey and a second survey, wherein the first survey and the second survey are shot with a bin size of L×L and the second survey is shot with a shooting direction rotated 90° relative to the shooting direction of the first survey. The combined seismic data from the first and second surveys are binned on a bin grid with a bin size of L 2 × L 2 and with a bin grid orientation rotated 45° relative to the shooting directions of the first and second surveys. Then, seismic data processing is applied to the binned seismic data to create an image of the Earth's subsurface.

Abstract: Pressure records and vertical particle velocity records from dual sensor towed streamer data are transformed to the inline wavenumber domain. A series of scaling filters are applied to the transformed vertical particle velocity records at each inline wavenumber, wherein each of the series of scaling filters is calculated for a different cross-streamer wavenumber range and in blocks of inline traces in which all seismic events are approximately linear. The pressure spectrum and the scaled vertical particle velocity spectrum are combined to separate upgoing and downgoing wavefield components. The separated upgoing and downgoing wavefield components are inverse-transformed back to the time-space domain.

Abstract: An optical sensor cable includes at least one light source fiber extending substantially the entire length of the cable. A plurality of optical sensors are functionally coupled at an input thereof to the at least one light source fiber. At least one signal return fiber extends substantially along the entire length of the cable and is functionally coupled to an output of each of the optical sensors. The at least one source light fiber and the at least one signal return fiber are configured to be coupled at either end thereof to a respective one of a light source and a photodetection device.

Abstract: A method for using signals measured by pressure responsive seismic sensors and motion responsive seismic sensors disposed in a seismic cable includes simulating a selected range frequency response of the motion responsive sensor signals for each of a plurality of selected depths in a body of water. For each sensor position along the streamer, the one of the simulated selected frequency range responses is selected for which the selected depth most closely matches an actual sensor depth. The selected simulated selected range frequency responses are combined with the measured motion responsive sensor signals to produce full bandwidth motion responsive signals. The full bandwidth signals are combined with the pressure responsive signals to determine at least one of an upgoing and downgoing pressure or motion wavefield.

Abstract: A method for interpreting seismic data below a salt layer includes depth migrating the seismic data to a bottom of the salt layer. The migrating including generating an initial model of velocities below the salt layer. The initial model is scaled by a plurality of scale factors at at least one image position. At least one of the plurality of scale factors for which a depth migrated image below the salt layer is optimum is selected as the scale factor.

Abstract: A marine electromagnetic survey cable includes a reference electrode extending substantially along the entire length of the cable. A plurality of spaced apart measuring electrodes is disposed along the cable and each is electrically insulated from the reference electrode. A voltage measuring is circuit functionally coupled between each measuring electrode and the reference electrode.

Abstract: A marine vibrator that in a particular embodiment includes a substantially elliptically shaped outer shell, a driver having a first and second end, at least one outer spring connected between the first end and the second end of the driver, and at least one inner spring connected between the first end and the second end of the driver. One or more masses are attached to the inner spring. At least one transmission element connects the outer spring and the outer shell. The outer and inner springs and the masses attached to the inner spring are selected to generate a first resonance frequency and a second resonance within the frequency range between 1 Hz and 300 Hz.

Abstract: Diagonal gather trace interpolation systems and methods are disclosed. In some embodiments, the method includes obtaining seismic traces from a marine seismic survey performed using typically two seismic sources fired in a flip-flop pattern. The seismic traces are processed in common field file trace groups from each cable by performing trace interpolation in opposing diagonal directions. Among other things, diagonal trace interpolation may improve azimuthal regularization. In any event, the disclosed interpolation methods maintain spatial bandwidth increased spatial resolution with increased inline and crossline sampling components. Diagonal gather trace interpolation exploits reduced input trace separation to provide improved stability and detection of a greater range of formation dip angles. After interpolation and regularization, the seismic traces may be imaged and interpreted for improved seismic exploration and monitoring.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of the jacket. The strength member is disposed inside the jacket. At least one seismic sensor is disposed in an interior of the jacket. An acoustically transparent material fills void space in the interior of the jacket. At least one longitudinally compressible element is disposed at a selected position along the streamer. The longitudinally compressible element fills substantially all void space within a cross-section of the interior of the jacket to separate the material into two compartments, thus attenuating transmission of acoustic waves in the material across the element.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of the jacket. The strength member is disposed inside the jacket. At least one seismic sensor is disposed in an interior of the jacket. An acoustically transparent material fills void space in the interior of the jacket. A plurality of spacers is disposed at spaced apart positions along the strength member, wherein the distance between the spacers is varied.

Abstract: A system comprises a plurality of seismic transmitters, at least one seismic source array, and a processor. Each seismic source array comprises a plurality of seismic source-array elements, mounted within the seismic source array; and a plurality of near-field sensors, wherein each near-field sensor is mounted within the seismic source array in the vicinity of one of the seismic source-array elements. The processor is adapted to determine relative positions of the seismic source-array elements on the seismic source array from the seismic signals transmitted by the seismic transmitters and received at the near-field sensors on the seismic source array.

Abstract: A seismic streamer includes a jacket covering an exterior of the streamer. At least one strength member extends along the length of the streamer and is disposed inside the jacket. At least one seismic sensor is disposed in a sensor spacer affixed to the at least one strength member. An encapsulant is disposed between the sensor and the sensor spacer. The encapsulant is a substantially solid material that is soluble upon contact with a void filling material. A void filling material is disposed in the interior of the jacket and fills substantially all void space therein. The void filling material is introduced to the interior of the jacket in liquid form and undergoing state change to substantially solid thereafter.