Abstract: The present invention provides an undersea seismic monitoring network, the monitoring network comprises at least one underwater vehicle and at least two monitoring stations located on the seabed, where each of the monitoring stations comprises at least one sensor for gathering seismic data and a radio modem for transmitting and receiving data to and from the underwater vehicle via a first wireless connection and where a second wireless connection is established between the monitoring stations, wherein the first wireless connection is formed by electromagnetic radiation through the water and the second wireless connection is formed by the propagation of an electromagnetic signal at least partially through the seabed.

Abstract: An improved system and method for seismic exploration using live steam involves creating a cavity of live steam in a body of water, the cavity of live steam imploding due to the water cooling the live steam thereby producing an acoustic pulse, receiving reflections of the acoustic pulse at one or more receivers, and processing the reflections of the acoustic pulse. The cavity of live steam can be created by controlling release valves to introduce live steam into the body of water or by introducing hydrogen and at least one of oxygen or air into the water to create a bubble and then igniting the bubble.

Abstract: Seismic processing method, in which, in order to eliminate multiple reflections on seismic data, seismic data are migrated in time or in depth (110) arid the data thus migrated are processed to determine an approximation of multiple reflections to be subtracted from, seismic data (120 to 160).

Abstract: A pressure wavefield and a normal velocity wavefield measured on a smoothly shaped acquisition surface by towed dual-sensor marine seismic streamers are decomposed into up-going and down-going pressure and particle velocity components on an observation level between the acquisition surface and a sea surface of undetermined shape. The up-going and down-going pressure and particle velocity components are extrapolated iteratively in steps from the observation level toward the sea surface. An image point and a reflection coefficient of the sea surface at the image point are determined from the iteratively extrapolated up-going and down-going pressure and particle velocity components.

Abstract: A method of predicting subsurface properties of a geologic formation includes acquiring seismic data for a subsurface region including the geologic formation of interest, computing seismic attributes of the measured seismic data over at least part of this geologic formation, determining internally consistent rock properties representative of the geologic formation, generating models of the same part of the geologic formation with these rock properties, computing synthetic seismic data from the models, computing the same attributes from these synthetic seismic data, and using Bayesian analysis to predict, from the probability of modeled attributes given the models, the probability of the actual subsurface properties given the measured attributes.

Abstract: A method for identifying a position of a source of noise in a marine seismic record includes defining, for at least one shot record, a set of possible noise source positions. A difference between travel time of noise from each possible noise source position to each of a plurality receiver position for the at least one shot record is determined. Signals from at least a subset of the receiver positions are time-aligned with respect to the difference between travel times for each possible noise source position. The time-aligned signals are then stacked. The noise source position is determined from the stacked, time-aligned signals. This result can then be used to construct a model of the noise at the receiver position.

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 technique facilitates the use of seismic data. The technique utilizes an autonomous underwater vehicle to obtain data on water column characteristics in a seismic survey area. The data can be used to adjust aspects of the seismic survey data and/or the seismic survey technique.

Abstract: A marine air gun generates an acoustic signal in water, for example, during a marine seismic survey. The marine air gun includes digital electronic circuitry. The digital electronic circuitry may control an actuator of the marine air gun, digitize and store data from sensors located on or near the marine air gun, send and/or receive digital communications, store and/or output electrical energy, and/or perform other functions. A marine seismic source system that includes multiple air gun clusters may have a separate digital communication link between a command center and each air gun cluster. Each communication link may provide power and digital communication between the command center and one of the air gun clusters.

Abstract: A technique includes obtaining first data indicative of seismic measurements acquired by seismic sensors of a first set of towed streamers and obtaining second data indicative of seismic measurements acquired by seismic sensors of a second set of towed streamers. The second set of towed streamers is towed at a deeper depth than the first set of towed streamers. The technique includes interpolating seismic measurements based on the first and second data. The interpolation includes assigning more weight to the second data than to the first data for lower frequencies of the interpolated seismic measurements.

Abstract: A technique includes obtaining different sets of data, which are provided by seismic sensors that share a tow line in common. Each data set is associated with a different spatial sampling interval. The technique includes processing the different sets of data to generate a signal that is indicative of a seismic event that is detected by the set of towed seismic sensors. The processing includes using the different spatial sampling intervals to at least partially eliminate noise from the signal.

Abstract: A method and apparatus for evaluating submarine formations, such as geological formations located generally under a body of water. Multiple hydrofoils (130), responding to moving water, hydrodynamic, or Bernoulli forces, provide controllable orientation and separation for multiple receivers (135) as they are towed (125) through water (110) in the course of a geophysical survey such as a controlled source electromagnetic survey. The inventive method can be used to provide mutual orthogonality for three antennas in a multiple component electromagnetic receiver.

Abstract: The present invention provides a method for pre-stack combining of over/under seismic data. The method includes determining a calibration filter using a first pre-stack marine seismic data set acquired at a first depth and a second pre-stack marine seismic data set acquired at a second depth, wherein the second depth is greater than the first depth and determining a third data set based upon the first pre-stack marine seismic data set, the second pre-stack marine seismic data set, and the calibration filter.

Abstract: A skeg mounts from the stern of a towing vessel and extends below the waterline. A channel in the skeg protects cables for steamers and a source of a seismic system deployed from the vessel. Tow points on the skeg lie below the water's surface and connect to towlines to support the steamers and source. A floatation device supports the source and tows below the water's surface to avoid ice floes. The streamers can have vehicles deployed thereon for controlling a position on the streamer. To facilitate locating the streamers, these vehicles on the streamers can be brought to the surface when clear of ice floes so that GPS readings can be obtained and communicated to a control system. After obtaining readings, the vehicles can be floated back under the surface. Deploying, using, and retrieving the system accounts for ice at the surface in icy regions. In addition, handling the seismic record can account for noise generated by ice impact events.

Abstract: A method for survey of hydrocarbon deposits in a researched profile of sea-bottom comprises providing a generator generating pulse electric current with a generator frequency in a towable generator line exciting electric field signals measured by sea-bottom stations synchronized with the generator, forming space-domain data arrays for the generator frequency and for higher odd harmonics frequencies nearest thereto, forming time-domain data arrays for selected offsets, inversion of the time-domain and space-domain data, and determining a bottom strata resistivity and polarization characteristics for the researched profile, based the inversion's results. The inversion preferably encompasses synchronizing and adjusting the generator line and electric field signals, dividing them into a frequency branch, including a fast Fourier transform and a robust summation producing the space-domain arrays, and a time-domain branch, including a robust summation producing the time-domain arrays.

Abstract: A method of filtering seismic signals is described using the steps of obtaining the seismic signals generated by activating a seismic source and recording signals emanating from the source at one or more receivers; defining a source signature deconvolution filter to filter the seismic signal, wherein the filter is scaled by a frequency-dependent term based on an estimate of the signal-to-noise (S/N) based on the spectral power of a signal common to a suite of angle-dependent far-field signatures normalized by the total spectral power of the signatures within the angular suite and performing a source signature deconvolution using the source signature deconvolution filter.

Abstract: A technique includes receiving seismic data, which are indicative of pressure measurements and pressure gradient measurements acquired in a seismic survey of at least one subterranean formation. The technique includes modeling an image of the subterranean formation(s) as a function of the pressure measurements and the pressure gradient measurements. The technique includes determining the image based on the modeling.

Abstract: A first weighted integral operator is applied to dual-sensor data to extrapolate the dual-sensor data to a first position above an acquisition surface, generating extrapolated data. A second weighted integral operator is applied to the extrapolated data to extrapolate the extrapolated data to a second position, generating wavefield separated data. One of the integral operators is applied to a scaled combination of the dual sensor data.

Abstract: A device and method for determining bottom sediment is provided. The method includes transmitting a pulse of a pulse width corresponding to a water-bottom depth, extracting a series of amplitude data of water-bottom echo signals from predetermined signals among the water-bottom echo signals received by the transducer at a predetermined time interval, normalizing the extracted series of amplitude data after TVG-processed, calculating two or more feature quantities based on the normalized series of amplitude data in each of segments of the normalized series of amplitude data, and a value corresponding to the water-bottom depth, and generating bottom-sediment classification information indicating the bottom sediment based on the two or more feature quantities.

Abstract: A system includes a seismic streamer, which includes particle motion sensors and processors. Each processor is associated with a different one of the particle motion sensors and is adapted to process data acquired by the associated particle motion sensor to compensate the data for a characteristic of the sensor.

Abstract: Various methods for simulating up-going pressure wavefield data. In one implementation, a processing apparatus may receive pressure data from pressure sensors that may be installed on a first and second streamer of an over/under streamer pair. The processing apparatus may also receive velocity data from velocity sensors that may be installed on the second streamer of the over/under streamer pair. Using the pressure and velocity data obtained from the sensors installed on each streamer, the processing apparatus may simulate the pressure and velocity data that would have been obtained by a streamer in a calm sea at a depth equal to the vertical distance between the first and second streamers. The simulated pressure and velocity data may then be combined to estimate the up-going pressure wavefield data.

Abstract: A method for determining quality of signals acquired using marine seismic streamers having pressure responsive sensors and motion responsive sensors includes cross ghosting pressure responsive seismic signals and contemporaneously acquired motion responsive seismic signals. First filters are determined that cause the cross ghosted pressure responsive signals to substantially match the cross ghosted motion responsive signals. Second filters are determined that cause the cross ghosted motion responsive signals to substantially match the cross ghosted pressure responsive signals. The first and second filters are convolved and the convolution is used to determine signal quality.

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 technique includes obtaining particle motion data and pressure data that are acquired by seismic sensors while in tow. The sensors are part of a plurality of streamers, and the pressure and particle motion data contain surface ghosts. The technique includes processing the particle motion data and the pressure data to generate a data set that is indicative of a pressure wavefield at positions between the streamers and is substantially free of the surface ghosts.

Abstract: There is provided a method of direct waveform inversion of turning waves (311, 312, 313) to determine parameters characterizing properties of the earth or sub-sections of the earth, particularly of parts of the earth which are capable of trapping hydrocarbons with the inversion yielding from the wavefield of turning waves information representing or being equivalent to velocities or slownesses and/or the gradient of velocities or slownesses, particularly by evaluating wavefield data in the vicinity of turning points (33). The method can be applied sequentially as a survey sinking method.

Abstract: A method of conducting multiple source, multiple signal seismic surveys in a marine environment are provided.

Abstract: A method for estimating formation quality factor includes determining an upgoing pressure wavefield of seismic signals recorded using a collocated pressure responsive sensor and motion responsive sensor deployed in a body of water The upgoing wavefield has spectral effect of water surface ghosting attenuated by combining the pressure responsive signals and motion responsive signals. The quality factor is determined by determining a difference in amplitude spectra between a first seismic event and a second seismic event in the upgoing pressure wavefield.

Abstract: A technique includes providing seismic data that is indicative of energy that is sensed in response to a first operation of at least one seismic source in a first seismic survey and a second operation of at least one seismic source in a second seismic survey. The technique includes processing the seismic data to determine a timing of the second operation relative to the first operation, and the technique includes based at least in part of the determined timing, processing the seismic data to generate a dataset, which is indicative of the sensed energy that is attributable to the first operation and is not attributable to the second operation.

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 processing seismic data acquired using a first over/under streamer and a second over/under streamer. In one implementation, the method may include estimating seismic data that would have been acquired by a third over/under streamer disposed at a depth equivalent to a distance separating the first over/under streamer from the second over/under streamer; and applying a dephase and sum algorithm to seismic data acquired by the first over/under streamer and the second over/under streamer and the estimated seismic data.

Abstract: A method for the quantitative characterization of a seabed sediment composition and a seabed's layered subbottom structure from at least one normal-incidence, single-channel reflection acoustic amplitude time series seismogram is disclosed. The method detects a plurality of reflections from subbottom interfaces in said seismograms, determines the traveltime, the polarity and the reflectivity of each detected reflection, determines the intrinsic attenuation of the sediment layer between pairs of adjacent reflections, and determines the acoustic properties, layer thicknesses and material properties of the seabed's layered subbottom structure as a function of said traveltimes, polarities and reflectivities of the detected reflections and said intrinsic attenuation of the sediment layer between pairs of adjacent reflections. A forward model describing the physical relationship between the material properties and the acoustic properties of seabed sediments is also disclosed.

Abstract: A merged particle velocity signal is generated by merging a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by velocity 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 time. Combined pressure and vertical particle velocity signals are generated by combining the recorded pressure and merged velocity signals.

Abstract: Apparatus and methods for acquiring seismic data using a seabed seismic data cable positioned on a seabed are described, including correcting for the effect of one or more sensor non-linear motions, which improves accuracy of seismic data. One or multiple non-linear movements of the sensor may be corrected for. It is emphasized that 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. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. 37 CFR 1.

Abstract: Methods are described for actively steering a towed marine seismic component using one or more actively controllable control members; reducing the actively steering of the control members during duration of a time window of recording seismic reflections from a sub-surface geological feature of interest; and resuming the actively steering of the control members after the time window. The marine seismic component may be a streamer, a source, or both. Other methods allow measuring initial orientation of a streamer based on measuring static control surface angle of a control surface of an inline steerable bird. This abstract is provided to comply with the rules requiring an abstract, and allow a reader to ascertain the subject matter of the technical disclosure. It will not be used to interpret or limit the scope or meaning of the claims.

Abstract: To estimate a far-field signature of a seismic source having plural source elements, seismic receivers are provided to receive signals from the seismic source elements of the seismic source. Seismic receivers are dynamically associated with different seismic source elements over time, and the far-field signature of the seismic source is computed according to the measurement data taken by the seismic receivers.

Abstract: A method for acquisition and processing of marine seismic signals to extract up-going and down- going wave-fields from a seismic energy source includes deploying at least two marine seismic energy sources at different depths in a body of water. These seismic energy sources are actuated with known time delays that are varied from shot record to shot record. Seismic signals from sources deployed at different depths are recorded simultaneously. Seismic energy corresponding to each of the sources is extracted from the recorded seismic signals. Up-going and down-going wave-fields are extracted from the sources deployed at different depths using the extracted seismic energy therefrom. A method includes the separated up-going and down-going wave-fields are propagated to a water surface or a common reference, the up-going or the down-going wave-field is 180 degree phase shifted, and the signals from these modified up-going and down-going wave-fields are summed.

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: A technique includes obtaining first measurements acquired by sensors of a towed seismic streamer, which are indicative of an inclination of the streamer. Based at least in part on the measurements, a shape of the streamer while in tow is determined.

Abstract: A method and system of seismic data processing includes acquiring first and second prestack seismic datasets wherein the seismic datasets have a time-lapse relationship. The first prestack seismic dataset is inverted to determine a first source wavelet data set and a first reflectivity parameters data set. A perturbation data set is obtained by simultaneously minimizing an Lp-Norm between a portion of the first reflectivity parameters data set and reflectivity parameters for the second data set, an Lp-Norm between the first source wavelet data set and a source wavelet for the second data set and an Lp-Norm for data misfit between the first prestack seismic data set and the second prestack seismic data set. The perturbation dataset may be inverted for petrophysical parameters and for determining time-lapse changes in a reservoir.

Abstract: The presently disclosed technique includes a method that compensates for constantly changing headings as occur during coil shooting acquisition. In one aspect, the presently disclosed techniques include a computer-readable program storage medium comprising: accessing a set of heading data for a seismic spread acquired while traversing a curved path; and normalizing the accessed heading data to a dynamic frame of reference defined relative to the seismic spread.

Abstract: A group of techniques can be used to determine if components of a seismic spread have deviated from a planned path during a coil or other curved and substantially circular acquisition pattern. In one aspect, and in general, the presently disclosed techniques include a computer-readable program storage medium for determining the deviation of spread array element from a planned curved path during a towed-array marine seismic survey. The method comprises: determining a nominal position of the spread array element at a given point in the planned curved path; determining the actual position of the spread array element; and performing an error analysis predicated on the nominal and actual positions.

Abstract: Methods and apparatus for determining an accurate differential transfer function (DTF) between two closely spaced hydrophones in a dual-hydrophone configuration such that the wavefield may be properly separated into up- and down-going components are provided. The methods disclosed herein are based on the premise that the cross-correlation at a lag of zero between up- and down-going wavefields should be at a minimum for perfectly matched hydrophones. Thus, any suitable global optimization technique may be utilized to determine an accurate DTF where the zero-lag cross-correlation between up- and down-going energy is at a minimum after multiplying a particular hydrophone spectrum of the pair (depending on how the DTF was defined) with a possible DTF suggested by the global optimization technique.

Abstract: A technique includes obtaining multi-component seismic data acquired by two or more seismic sensors while in tow. The multi-component seismic data is indicative of a pressure wavefield and particle motion. The technique includes based on the data, determining at least one high order (i.e., second order or higher) spatial derivative of the pressure wavefield.

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.

Abstract: A method for assessing data coverage in a three dimensional marine seismic survey includes determining at least one Fresnel zone for at least one of a plurality of seismic data traces. A contribution is determined for each of the seismic data traces to each one of a set of bins in a defined pattern. Each contribution is based on the Fresnel zone associated with each seismic data trace. The contributions from all seismic data traces contributing to each bin are summed. The summed contribution for each bin are stored or displayed and the summed contributions in each bin are compared to a selected threshold to determine coverage.

Abstract: A method for marine seismic surveying includes towing a seismic sensors in a plurality of streamers in the water, actuating a seismic energy source in the water at selected times and detecting seismic signals at the sensors resulting from the actuation of the source. A data trace is created for each of the detected signals. At least one Fresnel zone is determined for at least some of the seismic data traces. A contribution of each of the traces to each one of a plurality of bins defined in a predetermined pattern is computed, based on the Fresnel zone associated with each trace. Based on the computed contributions, a maximum lateral distance between corresponding seismic sensors is determined that will result in a contribution sum above a selected threshold.

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 technique includes performing at least one intervening towed seismic survey after a prior towed seismic survey and before a future towed seismic survey. The prior towed seismic survey has associated first streamer positions, and the future towed seismic survey has associated second streamer positions that do not coincide with the first streamer positions. The technique includes using measurements that are acquired in the intervening towed seismic survey(s) to link the prior towed seismic survey to the future towed seismic survey for time lapse analysis involving the prior and future towed seismic surveys.

Abstract: A method for monitoring a multi-layered system below a surface comprising a slow layer and a fast layer; the method comprising: transmitting one or more seismic waves from one or more seismic sources through the multi-layered system; receiving signals emanating from the multi-layered system in response to the one or more seismic waves with one or more receivers located a distance from the one or more seismic sources; identifying one or more critically refracted compressional (CRC) waves amongst the signals; and inferring information about a change in the slow layer based on the one or more CRC waves; wherein the CRC wave is a refracted wave which has traveled along an interface between the fast layer and an adjacent layer.