Abstract: A technique includes receiving seismic data acquired by seismic sensors; and processing the seismic data on a machine to deghost the data. The processing includes deghosting the seismic data using a first deghosting technique that relies on a ghost model; deghosting the seismic data using a second deghosting technique that is independent from any modeling of the ghost; and selectively combining the results of the deghosting using the first and second deghosting techniques.

Abstract: A method for selecting parameters of a seismic source array comprising a plurality of source elements each having a notional source spectrum is described, the method comprising calculating a ghost response function of the array; calculating directivity effects of the array; and adjusting the parameters of the array such that the directivity effects of the array are compensated by the ghost response to minimize angular variation of a far field response in a predetermined frequency range. A method for determining a phase center of a seismic source array is also related, the method comprising calculating a far field spectrum of the array at predetermined spherical angles, and minimizing the phase difference between the farfield spectra within a predetermined frequency range by adjusting a vertical reference position from which the spherical angles are defined.

Abstract: A sensor assembly has first sensors spaced apart along a first direction, and second sensors oriented in a second direction generally orthogonal to the first direction. Differencing of outputs of the first sensors is performed, and differencing of outputs of the second sensors is performed. A signal output is produced by combining the differenced outputs of the first sensors and the differenced outputs of the second sensors, where the signal output represents a seismic response of a subterranean structure.

Abstract: A tool is described for seismic data collection which may have sensors mounted along its entire length to sample both geophysical signal and noise including at least one of acoustic noise, system noise, and noise resulting from the interaction between the two. Systems and methods for acquiring borehole seismic data are also described. In contrast to conventional systems which attempt to avoid introducing noise into the collected data stream, the present systems include a sufficient type, number, and spacing of sensors to intentionally sample at least one source of noise. The methods include operating a borehole seismic acquisition system to sample both a target signal and at least one source of noise and using a processor with machine-readable instructions for separating the noise from the signal.

Abstract: The disclosure provides neutrally-buoyant tools for seismic data collection. The tools may range from several hundred meters to several kilometers in length and have integrated sensors which move along with the borehole fluid in response to a passing seismic wave. The disclosure also provides methods of deploying neutrally-buoyant tools, which includes using a tractor, adding a weight or both to the tool in order to overcome the difficulty of lowering a neutrally buoyant tool into a borehole, and optionally occasionally clamping the tool to the borehole to alleviate tension in the tool. This disclosure also provides methods of acquiring seismic data, which involves positioning a neutrally-buoyant tool in a borehole such that the tool is able to move relatively freely along with the borehole fluid in response to a seismic wave passing through the fluid, firing a seismic source, and using the sensors to collect seismic data generated thereby.

Abstract: To acquire near-zero offset survey data, a survey source and a first streamer attached to the survey source are provided, where the first streamer has at least one survey receiver. A second streamer separate from the survey source and the first streamer includes survey receivers. Near-zero offset data is measured using the at least one survey receiver of the first streamer.

Abstract: A method for selecting parameters of a seismic source array comprising a plurality of source elements each having a notional source spectrum is described, the method comprising calculating a ghost response function of the array; calculating directivity effects of the array; and adjusting the parameters of the array such that the directivity effects of the array are compensated by the ghost response to minimize angular variation of a far field response in a predetermined frequency range. A method for determining a phase center of a seismic source array is also related, the method comprising calculating a far field spectrum of the array at predetermined spherical angles, and minimizing the phase difference between the farfield spectra within a predetermined frequency range by adjusting a vertical reference position from which the spherical angles are defined.

Abstract: A sensor assembly includes a housing structure, a seismic sensor in the housing structure to measure seismic waves propagated through a subterranean structure, and a pressure sensor in the housing structure. A processor in the housing structure is configured to receive a first signal based on an output of the seismic sensor, and a second signal based on an output of the pressure sensor. First and second digital filters are applied to the first and second signals. Application of the first and second digital filters to the first and second signals causes production of a substantially zero output in response to input that includes just noise data detected at the seismic sensor and the pressure sensor.

Abstract: Generating an image of an interior of the Earth from a seismic survey using multiple sources. The multiple sources may be fired simultaneously and the data received by seismic sensors in the seismic survey may be decomposed so that seismic data generated by each of the multiple sources may be determined. Decomposing of the received data may be performed using frequency diverse basis functions and converting the data separation problem into an optimization problem, which can be a one-norm or zero-norm optimization problem in frequency-space domain. The decomposed data may be used to generate the image of the Earth's interior.

Abstract: Measured seismic data is received from a seismic sensor. Rotation data is also received, where the rotation data represents rotation with respect to at least one particular axis. The rotation data is combined, using adaptive filtering, with the measured seismic data to attenuate at least a portion of a noise component from the measured seismic data.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: A method for processing seismic data. The method includes receiving the seismic data acquired at two or more sensors on a towed marine survey and regularizing the received seismic data into a spatial domain. After regularizing the seismic data, the method includes classifying the regularized seismic data below and equal to a predetermined frequency as low-frequency seismic data. The method then calculates a set of low-frequency Green's functions using interferometry on the low-frequency seismic data described above. The method then processes high-frequency seismic data of the seismic data to create a set of high-frequency Green's functions at one or more source locations of the towed marine survey. After creating the set of high-frequency Green's functions, the method merges the set of low-frequency Green's functions and the set of high-frequency Green's functions to create a set of broad-band Green's functions at the source locations.

Abstract: Embodiments of the invention provide a method of processing marine seismic data, the data having been acquired using a “dense over/sparse under” streamer array having N over streamers disposed at a first depth and M under streamers disposed at a second depth greater than the first depth, where 0<M<N. The method comprises: a) processing seismic data for one of the over streamer target locations and seismic data for one of the under streamer target locations; b) processing seismic data for another of the over streamer target locations; and c) combining the result of (a) and the result of (b). The one of the over streamer target locations and the one of the under streamer target locations may lie in a vertical plane.

Abstract: A method for attenuating out of band energy emitted from a seismic source used in a marine seismic survey. The method includes disposing the seismic source in a body of water and releasing a gas into a volume of water surrounding the seismic source. The released gas may be configured such that it displaces the volume of water surrounding the seismic source at a rate less than 2.9×106 cubic-meters per cubic-second.

Abstract: Designing a multi-dimensional Finite Impulse Response FIR digital filter to attenuate the coherent noise while preserving reflection signals on seismic data, particular in land seismics, comprises computing filter coefficients to minimise an l-norm function of differences between a response of a filter with the computed coefficients and a predetermined response which attenuates signals outside a predetermined range of slowness relative to signals within the predetermined range of slowness. Additional constraints may be imposed on the coefficients to improve the attenuation of signals outside the predetermined range of slowness of the desired reflection signals, and/or to improve uniformity within the desired range.

Abstract: A sensor assembly has first sensors spaced apart along a first direction, and second sensors oriented in a second direction generally orthogonal to the first direction. Differencing of outputs of the first sensors is performed, and differencing of outputs of the second sensors is performed. A signal output is produced by combining the differenced outputs of the first sensors and the differenced outputs of the second sensors, where the signal output represents a seismic response of a subterranean structure.

Abstract: A distributed optical acoustic sensor is provided along a structure in a body of water. The distributed optical acoustic sensor is used to detect acoustic waves generated by at least one acoustic source for positioning of at least one object in relation to the structure.

Abstract: One embodiment of the invention concerns a probe that couples to a seismic vessel via a tow cable. When deploying probes from a seismic vessel that is towing source arrays and streamers, the probe and its tow cable can tangle with elements of the towed seismic spread. However, a cable guide may be used to lessen the risk for such entanglement by guiding the tow cable into the water at a distance removed from the seismic spread. Also, the probe may be steerable to steer the probe and tow cable away from the seismic spread. Other embodiments are described herein.

Abstract: An improved de-ghosting method and system that utilizes multi-component marine seismic data recorded in a fluid medium. The method makes use of two types of data: pressure data that represents the pressure in the fluid medium, such as sea water, at a number of locations; and vertical particle motion data that represents the vertical particle motion of the acoustic energy propagating in the fluid medium at a number of locations within the same spatial area as the pressure data. The vertical particle motion data can be in various forms, for example, velocity, pressure gradient, displacement, or acceleration. A spatial filter is designed so as to be effective at separating up and down propagating acoustic energy over substantially the entire range of non-horizontal incidence angles in the fluid medium.