Abstract: A sweep generator is employed to generate a sweep to be used by a seismic vibrator device for generating a desired target output spectrum, wherein the frequency sweep is designed so as to comply with one or more constraints imposed by the seismic vibrator device and/or imposed by the environment in which the device is to be used. In one embodiment, a sweep generator determines a sweep for achieving a desired target output spectrum by a given seismic vibrator device in compliance with at least a pump flow constraint imposed by the seismic vibrator device. In another embodiment, a sweep generator determines a sweep for achieving a desired target output spectrum by a given seismic vibrator device in compliance with all of multiple operational constraints of the seismic vibrator device, such as both mass displacement and pump flow constraints. Environmental constraints may also be accounted for in certain embodiments.

Abstract: A computer implemented technique for use in seismic data interpretation and, more particularly, with respect to near-surface geological structures, includes a computer-implemented method, including: jointly interpreting a plurality of complementary data sets describing different attributes of a near-surface geologic structure; and ascertaining a near-surface geomorphology from the joint interpretation. In another aspect, the technique includes a program storage medium encoded with instructions that, when executed, perform such a method. In yet another aspect, the method includes a computing apparatus programmed to perform such a method.

Abstract: A system includes an electrical medium and a string of sensor assemblies having corresponding outputs connected to the electrical medium, where at least one of the sensor assemblies includes a seismic sensor to measure seismic waves propagated through a subterranean structure, and a pressure sensor. The sensor assembly further includes at least one matching circuit connected to an output of at least one of the seismic sensor and pressure sensor, where the at least one matching circuit is configured to suppress noise. An output signal of the at least one matching circuit is connected to the electrical medium to produce a combined signal that is representative of characteristics of the subterranean structure and in which the noise is suppressed.

Abstract: A technique includes determining at least one parameter that characterizes a seismic survey in which multiple interfering seismic sources are fired and seismic sensors sense energy that is produced by the seismic sources. The determination of the parameter(s) includes optimizing the seismic survey for separation of the sensed energy according to the seismic sources.

Abstract: Methods and apparatuses are disclosed for replacing the individual receivers used with a seismic interferometry process with an array of seismic receivers and then manipulating the array data in order to measure and modify the typical non-uniform directionality function of the background seismic energy. The non-uniform directionality function is a significant cause of noise with seismic interferometry. Furthermore, the array of receivers may be used to significantly enhance the preferred reflection energy and damp undesirable near surface energy. The directionality function may be modified by using an array of receivers for the virtual source location of seismic interferometry to measure the non-uniform directionality function, generating multiplication factors, and applying the multiplication factors to convert the measured directionality function into a desired directionality function.

Abstract: Systems and methods for seismological sounding with acoustic signals and, more particularly, systems and methods for performing geophysical surveys using spread spectrum acoustic waves generated by non-impulsive sources. A spread spectrum signal is generated and coupled to a medium that is to be sounded for propagation of an acoustic wave through the medium. One or more return signals are received from the medium that are generated by interaction between the acoustic wave and the medium. The return signals are possessed to obtain seismic sounding data describing the structural features of the medium.

Abstract: A method for evaluating a quality of a seismic inversion. The method includes performing a first match between seismic data and borehole seismic data at one or more borehole locations to generate an estimate of a wavelet in the seismic data. The method then performs a seismic inversion on the seismic data using the estimate of the wavelet to generate inverted seismic data. After performing the seismic inversion, the method converts the inverted seismic data into one or more reflectivity traces. The method then includes performing a second match between the one or more reflectivity traces and one or more traces in the seismic data and performing a third match between the one or more reflectivity traces and one or more traces in the borehole seismic data. After performing the second and third matches, the method determines the quality of the seismic inversion based on the first match, the second match, the third match or combinations thereof.

Abstract: Method for analysis of hydrocarbon potential of subterranean regions by generating surfaces or geobodies and analyzing them for hydrocarbon indications. Reflection-based surfaces may be automatically created in a topologically consistent manner where individual surfaces do not overlap themselves and sets of multiple surfaces are consistent with stratigraphic superposition principles. Initial surfaces are picked from the seismic data (41), then broken into smaller parts (“patches”) that are predominantly topologically consistent (42), whereupon neighboring patches are merged in a topologically consistent way (43) to form a set of surfaces that are extensive and consistent (“skeleton”). Surfaces or geobodies thus extracted may be automatically analyzed and rated (214) based on a selected measure (213) such as one or more direct hydrocarbon indications (“DHI”), e.g. AVO classification.

Abstract: A method for seismic event mapping includes selecting a plurality of subvolumes representing possible locations of origin of a seismic event in the Earth's subsurface. For each subvolume a plurality of possible directions of motion of subsurface formations is selected. For each subvolume and each possible direction of motion, polarity correction is applied to seismic signals recorded at a plurality of positions proximate a volume of the Earth's subsurface to be evaluated. The polarity correction is based on the direction of motion and the position of each seismic sensor with respect to the subvolume. The recorded, polarity corrected seismic signal recordings are time aligned. The time aligned recordings are summed. A most likely direction of motion and subvolume position are determined based on a selected attribute of the summed, time aligned seismic signals.

Abstract: A new seismic attribute is disclosed along with its use to locate and classify seismic waveform anomalies and use them to construct objects and from them geologic surfaces (77) and bodies (75) from which hydrocarbon potential (or quality control of the seismic acquisition and processing (71)) may be assessed (79). The seismic attribute is constructed (74) from determinations of phase residues in the seismic data volume (72), preferably using complex trace analysis but alternatively by comparing neighboring waveforms for disappearing waveshape inflections. It is shown that in a data volume of the new attribute, non-zero values form strings and loops that may be associated with objects (geobodies) or surfaces such as unconformities or flooding surfaces. Methods of classification and selection (76) to reduce the number of objects generated are provided.

Abstract: A method for processing geophysical data. The method includes applying a first interferometry on an estimate of a direct ground roll between a receiver location and one or more boundary source locations and an estimate of a direct ground roll between one or more boundary receiver locations and each boundary source location to generate an interferometric estimate of a direct ground roll between the receiver location and each boundary receiver location. The method then includes applying a second interferometry on geophysical data between the source location and each boundary receiver location and the interferometric estimate of the direct ground roll between the receiver location and each boundary receiver location to generate an interferometric estimate of a direct and scattered ground roll between the source location and the receiver location.

Abstract: Method for designing a converted mode (PS or SP) seismic survey to accomplish specified vertical and lateral resolution objectives at target depth. An equation (181) is provided for determining the minimum bandwidth required for a desired vertical resolution at a selected scattering angle, as a function of incident and reflected wave velocities, one of which is the P-wave velocity and the other is the S-wave velocity. A second equation (182) is provided for determining migration acceptance angle from the desired vertical and lateral resolutions. Source and receiver apertures may then be determined by ray tracing. Finally, a third equation (183) is provided for the maximum bin size to avoid aliasing, given the migration acceptance angle and a maximum frequency needed to achieve the bandwidth requirement. Source and receiver spacing may then be based on the maximum bin size.

Abstract: There is described a method of moveout or velocity analysis of seismic signals using the steps of obtaining such signals 5 from a plurality of receivers, identifying receiver functions within the acoustic signals, analyzing said receiver functions for velocity or moveout characteristics, using the result of said analyzing step to determine, properties of multiple layers of earth located below said 10 receivers. The analyses can involve the use of representation of the traveltime differences as approximated power series of slowness or horizontal distances. The method is the first to comprehensively deal with a multi-layered earth or velocity model.

Abstract: Remote seismic surveying systems and methods are disclosed. At least some embodiments illuminate a water or ground surface with a beam from a coherent electromagnetic wave source. Reflected electromagnetic energy is focused onto an image plane where it combines with a reference beam to form an interference pattern. Electronics track the intensity versus time for multiple points in the image and derive displacement signals for various physical locations in the survey region. These displacement signals are associated with seismic source firing times and locations before being stored as seismic traces in a survey database. Some variations use the reflected electromagnetic energy to create multiple interference patterns that vary due to different path length differences, thereby eliminating signal phase ambiguities.

Abstract: An embodiment of the invention relates to a method of processing seismic data comprising a plurality of traces, each trace having a source position, a receiver position and a midpoint position, each having coordinates in an inline direction and a crossline direction. The invention uses a data set comprising traces having one of the source position, the receiver position or the midpoint position having coordinates which are invariant in one of the inline or the crossline directions. A non-iterative surface related multiple attenuation algorithm is applied to the data set which assumes substantial non-variation of depth of reflectors in the same one of the inline or the crossline directions.

Abstract: The invention relates to a method of processing seismic data acquired by means of a sensor having at least three geophone components, characterized in that estimators are determined which are combinations of these components making it possible to isolate the various data depending on whether they correspond to propagation with reflection or with conversion. The estimators find application in particular for determining a sensor reconstruction according to which the operators to be applied to the various components of the sensor are determined in such a way as to minimize the deviation between reference data and data obtained by applying the estimators to the sensor reconstruction, the operators thus determined being applied to the data acquired.

Abstract: The technologies described herein include systems and methods for encoding/decoding seismic sources and responses, generating and using of source-side derivatives while also generating and using the conventional source response. Sources in an array may be encoded such that activation of each source in the array constitutes a single spike in a sequence orthogonal to another sequence emitted by another source. The responses to these different sources that are in close spatial proximity can be decoded and separated. Source-side derivatives may be calculated and utilized in various applications in combination with the monopole response from the source location, including source-side deghosting, spatial (horizontal and vertical) interpolation and imaging.

Abstract: Seismic systems and methods are provided to collect variable seismic data, for coordinating source energy and receiver data as well as using both to obtain high resolution seismic data.

Abstract: A computer-implemented method of accounting for angle-dependent wavelet stretch in seismic data based on a novel relationship between wavelet stretch and the cosine of a reflection angle of an acoustic ray. Conventional seismic data having at least one wavelet, such as data generated from a reflection seismic survey, is accessed. The data is processed such that at least one wavelet is subject to angle-dependent wavelet stretch. A reflection angle for at least one wavelet is also determined. An operator is utilized to calculate a wavelet stretch factor for at least one wavelet based on the cosine of the corresponding reflection angle of the wavelet. The wavelet stretch factor is applied to the seismic data to account for angle-dependent wavelet stretch.

Abstract: A method and apparatus for pre-inversion noise attenuation of seismic data. The method can generally comprise: (a) acquiring seismic data including receiver data corresponding to vibratory signals simultaneously generated by the multiple sources and detected by at least one of the receivers at a location remote from the sources and source data corresponding to the vibratory signals detected at a location in proximity to the sources; (b) attenuating noise present within at least a portion of the receiver data to generate corrected receiver data; and (c) inverting the corrected receiver data with the source data to separate the vibratory signals.

Abstract: A method and apparatus for minimizing interference between seismic systems. The method may generally include: (a) actuating a plurality of first sources associated with a first seismic system to generate a first plurality of phase-encoded vibratory signals; (b) actuating a plurality of second sources associated with a second seismic system to generate a second plurality of phase-encoded vibratory signals that are at least partially frequency separated from the first plurality of phase-encoded vibratory signals generated in (a); and (c) detecting the first and second plurality of phase-encoded vibratory signals utilizing a first receiver positioned at a location remote from the first and second sources.

Abstract: There is provided a method of spatially shifting seismic signals acquired through a seismic survey using the steps of identifying within the signals a set of N actual locations of seismic receivers and corresponding N seismic signals received by the set of seismic receivers; identifying a set of N? desired locations of seismic receivers; and determining a set of N? signal values at said N? desired locations by evaluating for each of said N? signal values a weighted sum of the N seismic signals, wherein the weights are at least partly determined by the relative distance between pairs of locations selected from said set of N actual locations of seismic receivers.

Abstract: Methods and apparatuses are disclosed for replacing the individual receivers used with a seismic interferometry process with an array of seismic receivers and then manipulating the array data in order to measure and modify the typical non-uniform directionality function of the background seismic energy. The non-uniform directionality function is a significant cause of noise with seismic interferometry. Furthermore, the array of receivers may be used to significantly enhance the preferred reflection energy and damp undesirable near surface energy. The directionality function may be modified by using an array of receivers for the virtual source location of seismic interferometry to measure the non-uniform directionality function, generating multiplication factors, and applying the multiplication factors to convert the measured directionality function into a desired directionality function.

Abstract: A technique includes accessing seismic data that is associated with seismic measurements taken from a reservoir and a surrounding rock mass at a given time. Based on a velocity model developed from a predicted change in the reservoir and surrounding rock mass occurring from a prior to the given time, processing the seismic data to generate a survey of the reservoir and surrounding rock mass.

Abstract: A downhole tool starts recording seismic energy. During the recording time, a surface seismic source is activated a specified number of times with a nominally defined separation between successive. The downhole sensor receives seismic waves resulting from the activation, but the time of the shooting sequence is not known downhole. The recorded data stream is processed and converted in real-time into seismic traces. A predefined number of traces are stacked and the quality of this sliding stack is used to detect time of the shooting sequence. The method could be used to detect one or several shooting sequences during a measurement window.

Abstract: A system, method, and computer program configured to provide an electronic method for seismic time-lapse characterization of an underground formation are provided. The method includes decomposing, with microprocessor executing a predefined set of instructions stored in a memory, baseline and monitor seismic survey data of a formation into a four dimensional Clifford Algebraic form; extracting, via the microprocessor, time delays from a matrix of decomposed sensor measurement vectors generated based on the four dimensional Clifford Algebra form; and determining, via the processor, time strains for the underground formation from differences in the extracted time delays from the matrix before displaying the determined time strains for the underground formation to a user via a monitor or a hard copy printed document. A procedure is also provided to calibrate and refine the static and dynamic models of an underground formation using the results from the seismic time-lapse characterization.

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: To attenuate a surface seismic wave, seismic sensors having a predetermined orientation with respect to a surface are provided, where the seismic sensors receive seismic waves including a seismic wave reflected from a subterranean structure and the surface seismic wave propagating in at least a first direction that is generally parallel to the surface. A signal that represents a partial derivative of a wavefield containing the surface seismic wave is provided, and the signal is integrated to obtain a response in which the surface seismic wave is attenuated.

Abstract: A technique is provided for identifying an internal multiple generator in a subterranean structure. The technique includes injecting wavefields at different levels in the subterranean structure, where the different levels are proximate a predicted location of the internal multiple generator. Wavefields induced by the injected wavefields are recorded and the effect of the internal multiple generator based on the recorded wavefields is determined.

Abstract: First-order free-surface multiples recorded in VSP data or reverse VSP data are processed using VSP/CDP method to produce an image of the subsurface. This image produces a larger coverage than that obtained in 3-C 3-D processing of reflection data acquired in the VSP.

Abstract: An apparatus and method for mapping a water pathway. A group of sensors can be employed for detecting one or more features associated with the water pathway in a direction of flow through the water pathway. A buoyant vessel maintains the sensors, and the sensors assist in compiling data indicative of the detected features. The velocity in the direction of flow through the water pathway can be then determined based on data indicative of the detected feature(s). A mapping of the water pathway can be thereafter generated utilizing the velocity with respect to the features detected by the sensors.

Abstract: Measurements made by a transducer assembly for downhole imaging are affected by reverberations between the transducer and the window on the outside of the assembly. The reverberations result in a stationary noise on the image. Hardware solutions to improve signal-to-noise ratio includes using a composite transducer, adjusting the distance between the transducer and the window. SNR can also be improved by processing techniques that include stacking, fitting a sinusoid to the reverberation, by envelope peak detection, and by applying a notch filter.

Abstract: Systems, methods, and apparatus are described that provide for analysis of seismic data. Features of temporal gait patterns can be extracted from seismic/vibration data. A mean temporal gait pattern can be determined. A statistical classifier can be used to model features of the data. The model can be used to classify the data. As a result, discrimination of seismic sources can be performed. Systems for discrimination of seismic data are also described. A system can include a vibration sensor system configured and arranged to detect vibrations. A system can also include a processor system configured and arranged to receive data from the vibration sensor, recognize the seismic data as belonging to a particular class of seismic data, and produce an output signal corresponding to the recognized particular class of seismic data.

Abstract: Systems and methods are implemented for evaluating underground structures and objects, particularly relatively shallow underground structures and objects, using a seismic or acoustic source signal and a resulting seismic or acoustic wave. A discrete or unitary apparatus incorporates both a seismic source transducer and a receiver transducer within a common housing or frame. A unitary seismic probe includes a ground engaging member and a seismic source mechanically coupled to the ground engaging member. The probe further includes a sensor assembly mechanically coupled to the ground engaging member and configured to sense ground vibrations resulting from an impact to the ground engaging member by the seismic source.

Abstract: An acoustic source on a logging tool is used to generate acoustic waves in a borehole. Acoustic detectors on the logging tool measure the generated acoustic waves. Electrodes on the logging tool are used to measure the potential resulting from the generated acoustic wave. The output of the hydrophones and the electrodes corresponding to Stoneley wave components of the acoustic wave are processed to provide an estimate of formation permeability, acoustoelectric constant, and a velocity of a propagating second compressional wave in the formation.

Abstract: A method including analyzing seismic data relating to a producing hydrocarbon reservoir is disclosed. The seismic data includes first and second sets of seismic data obtained at different times. An interval composed substantially of hard rock is identified in the hydrocarbon reservoir. 4D seismic attributes for the region are calculated. Rock physics relationships are applied to seismic data related to the interval according to the permeability associated therewith. A fluid saturation change or a pressure change of the interval is inferred based on outputs of the first or second sets of rock physics relationships and the calculated 4D attributes for the interval. The inferred fluid saturation change or pressure change of the interval is outputted.

Abstract: A computer implemented method for the detection of features such as faults or channels in seismic images. First, edges are detected in a smoothed seismic image (106). To detect a fault line, an image intensity of the edges is projected in multiple spatial directions, for example by performing a Radon transform (118). The directions of maximum intensity are used to define a fault line (124c). To detect channels, smooth curves are identified within the detected edges (810). Sets of parallel smooth curves (812a) are then identified and used to define channels (812).

Abstract: A method for determining seismic anisotropy of subsurface rock formations includes measuring passive seismic signals at a plurality of locations above an area of the Earth's subsurface to be surveyed. The compressional- and shear-wave arrival times from at least one origin location of a seismic event occurring in the subsurface are determined from the measured seismic signals. The arrival times are inverted to obtain values of the seismic anisotropy parameters.

Abstract: Methods and systems for analyzing subterranean formations in-situ stress are disclosed. A method for extracting geological horizon on-demand from a 3D seismic data set, comprises receiving sonic log data; computing the anisotropic shear moduli C44, C55 and C66; determining in-situ stress type and selecting an in-situ stress expression corresponding to the in-situ stress type; computing stress regime factor Q of the formation interval; and computing and outputting the maximum stress ?H by using the stress regime factor Q, Vertical stress ?v and Minimum horizontal stress ?h.

Abstract: A Laplace transform system comprising a processor, a measured time domain wavefield, a velocity model, and Laplace damping constants, wherein the processor is programmed to calculate a substantially about zero frequency component of a Fourier transform of a time domain damped wavefield, wherein the time domain damped wavefield is damped by the Laplace damping constants to obtain long wavelength velocity information for deeper subsurface regions.

Abstract: A method of processing seismic data comprises processing data representative of the acceleration wavefield so as to obtain information about the earth's subsurface direct from the seismic data representative of the acceleration wavefield. In conventional techniques for processing seismic data representative of the acceleration wavefield the data are transformed to the velocity domain at an early stage in the processing. The invention enables the transform step to be eliminated, thereby simplifying the processing and eliminating the risk that the transform might degrade the data. Furthermore, the increased sensitivity at high frequencies of a typical acceleration sensor compensates for the low-pass filter effect of the earth.

Abstract: There is provided herein a system and method for the imaging and monitoring of hydrocarbon reservoirs and other subsurface features preferably using seabed or surface sensors in conjunction with one or more downhole sensors. In one preferred embodiment, recordings will be simultaneously made using both seabed and downhole receivers. The energy source might be either a controlled seismic source or ambient noise. In one embodiment, the data will be used to compute a virtual VSP, checkshot, or similar survey by cross correlating a trace recorded at the surface with a trace recorded at depth. In another embodiment, the surface and well sensors will be permanently emplaced and repeated recordings over time will be used to form a time-varying (4-D) image of the subsurface.

Abstract: Methods for generating a time lapse difference image. In one implementation, the method includes estimating a trace in a first seismic survey data set at each trace coordinate of a second seismic survey data set, estimating a trace in the second seismic survey data set at each trace coordinate of the first seismic survey data set and calculating trace differences between the first seismic survey data set and the second seismic survey data set at each trace coordinate of the first seismic survey data set and the second seismic survey data set.

Abstract: A seismic sensor module includes sensing elements arranged in a plurality of axes to detect seismic signals in a plurality of respective directions, and a processor to receive data from the sensing elements and to determine inclinations of the axes with respect to a particular orientation. The determined inclinations are used to combine the data received from the sensing elements to derive tilt-corrected seismic data for the particular orientation.

Abstract: An apparatus includes an array of seismic sensor units that are adapted to acquire measurements in connection with a land surface-based seismic survey. Each seismic sensor unit includes a particle motion sensor and a rotation sensor.

Abstract: Systems and methods create a velocity model for well time-depth conversion. In one implementation, a system optimizes a time-depth relationship applied to data points from a single well to estimate coefficients for a velocity function that models the data points. The system optimizes by reducing the influence of outlier data points, for example, by weighting each data point to decrease the influence of those far from the velocity function. The system also reduces the influence of top and bottom horizons of geological layers by applying data driven techniques that estimate the velocity function without undue dependence on the boundary conditions. The system can optimize estimation of a rate of increase in velocity to enable the velocity function to go through a data point on each top horizon. The system may also estimate each base horizon from trends in the data points and adjust the velocity function to go through a data point on each base horizon.

Abstract: A seismic processing method of the migration type, comprising the steps of: linearly combining downgoing waves generated at a plurality of shotpoints, and also upgoing waves recorded by a plurality of seismic sensors; notionally propagating the composite waves as obtained in this way in order to obtain migrated downgoing and upgoing waves for different depths; and determining at a plurality of depths at least one characteristic of the subsoil as a function of the upgoing and downgoing waves propagated in this way; the downgoing (resp. upgoing) composite waves being calculated by a linear combination of downgoing (resp. upgoing) waves in which said downgoing (resp. upgoing) waves are weighted by the coefficients of a spatial modulation matrix which is a function of the positions of the shotpoints.

Abstract: A method of processing seismic data, wherein a digital seismic trace is provided comprising at least one seismic loop. A selected discrete wavelet transform of the digital seismic trace is obtained as a function of scale sj and shifted sample time tk. From the discrete wavelet transform, a singularity spectrum is obtained for the at least one seismic loop, and a selected function is fitted to the singularity spectrum. Based on the fitted function, a reconstructed seismic trace may be calculated. The method may be embodied in the form of software code instructions in a computer program product.

Abstract: This patent delineates methods for quantifying and mitigating dip-induced azimuthal AVO effects in seismic fracture detection using Azimuthal AVO analysis by accurately accounting for the divergence correction and azimuthal dependence of the reflection angle. Solutions are provided for three cases: (1) dipping isotropic reservoirs; (2) anisotropic reservoirs with fractures aligned in arbitrary direction; and (3) anisotropic reservoirs where vertical fractures are aligned perpendicular to the dip direction.

Abstract: An estimated frequency-wavenumber spectrum is generated by applying a first Anti-leakage Fourier transform method to unaliased frequency components in temporal-transformed seismic data and applying a second Anti-leakage Fourier transform method to aliased frequency components in the temporal-transformed seismic data. The second Anti-leakage Fourier transform method applies an absolute frequency-wavenumber spectrum extrapolated from unaliased frequencies to aliased frequencies to weight frequency-wavenumber components of the aliased frequencies. An inverse temporal and spatial Fourier transform is applied to the estimated frequency-wavenumber spectrum, generating trace interpolation of the seismic data.