Abstract: Method for deriving a reservoir property change data volume from time shifts used to time-align 4D seismic survey data (31). The time alignment is performed on at least one angle stack of 4D data to determine a time-shift data volume (32). When multiple angle stacks are used, the time shifts are corrected to zero offset. A running time window is defined, and within each window the time shifts are best fit to a straight-line function of time (depth), one angle stack at a time (33). The slopes from the straight line fits from different angle stacks are averaged at each voxel in the data volume, which yields a reservoir properties (??/?) data volume (34). This data volume may be filtered with a low-pass filter to improve signal-to-noise (35). The resulting data volume may be merged with the 4D data volume to expand its bandwidth (36), or it may be converted into a reservoir saturation and pressure change data volume (38) using a rock-physics model (37).

Abstract: Systems and methods for modeling a three-dimensional (3D) geological structure to improve maximum continuity interpolation. An integration method describes local anisotropic effects and introduces interpolation techniques to perform the interpolation between two points of interest along a direction of maximum continuity and across fault surfaces.

Abstract: The disclosure describes a method and apparatus for effectively communicating data along an acoustic transmission path. The method comprises driving an acoustic transmitter to send a data signal along the acoustic transmission path, where the signal is distorted by ambient noise. The distorted signal is input to a spaced apart plurality of sensors so that consequent time-delayed signals provide reinforcement of the basic signal and attenuation of the ambient noise component when combined.

Abstract: Seismic acquisition systems are disclosed that allow contemporaneous seismic sources to be separated from a composite signal comprising two or more constituent seismic sources. In some embodiments, a representation of the composite signal may be developed that includes a noise contribution of undesired signals present in the composite signal. Additionally, an operator, referred to herein as an “annihilator”, may be developed such that it may be conditioned and inverted to minimize undesired noise contributions in the composite signal. This inversion may assist in recovering the constituent seismic sources from the composite signal. Furthermore, in some embodiments, the accuracy with which the constituent source measurements are approximated may be increased by implementing them as random sweeps having a conventional length.

Abstract: A super-gather is constructed by interleaving traces from a hydrophone gather and a geophone gather in seismic data such that traces pertaining to co-located hydrophones and geophones are adjacent to each other. A noise-attenuated super-gather, generated by applying an f-x domain noise identifying and attenuation process to the super-gather, is subtracted from the super-gather to generate a super-gather noise model. A hydrophone gather noise model, generated by removing non-noisy geophone gather traces from the super-gather noise model, is subtracted from the hydrophone gather to generate seismic data with interference noise attenuated.

Abstract: A method is disclosed for combining seismic data sets. This method has application in merging data sets of different vintages, merging data sets collected using different acquisition technologies, and merging data sets acquired using different types of sensors, for example merging hydrophone and geophone measurements in ocean bottom seismic data.

Abstract: Methods and apparatus for processing dual sensor (e.g., hydrophone and vertical geophone) data that includes intrinsic removal of noise as well as enhancing the wavefield separation are provided. The methods disclosed herein are based on a decomposition of data simultaneously into dip and frequency while retaining temporal locality. The noise removed may be mainly coherent geophone noise from the vertical geophone, also known as V(z) noise.

Abstract: A technique includes spatially filtering a signal that is derived from a seismic acquisition. The filtering is associated with a filter length, and the filtering includes varying the filter length with frequency. The filtering may be used in connection with adaptive noise attenuation, which is applied to decomposed subbands. Furthermore, the filtering may be applied during the reconstruction of the signal from the subbands.

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: A sensor assembly having improved characteristics for use in surveying a subterranean structure includes a divergence sensor for positioning at or below a ground surface, where the divergence sensor includes a container containing a material and a pressure sensor immersed in the material. In addition, the sensor assembly includes a single-component seismic sensor that is external to the container of the divergence sensor.

Abstract: Apparatus and methods are described for attenuating noise associated with atmospheric pressure fluctuations in a seismic signal during seismic data acquisition using at least a pair of sensors comprising a seismic sensor and a pressure sensor for concurrently receiving a seismic signal and a pressure signal respectively, the sensors being adapted individually to transmit the respective seismic and pressure signals to a remote recording station which is adapted to record a plurality of seismic and pressure signals; and a filter for removing, at least partly, noise associated with atmospheric pressure fluctuations in the seismic signal, the filter employing an input signal from the pressure sensor; and a model of the coupling between the atmosphere and the ground to generate a reference signal which is combined with the seismic signal to produce an output signal.

Abstract: The invention is a method to predict surface-wave waveforms (306) and subtract them (307) from seismic data. Prediction is done by estimating a set of surface-consistent components (transfer functions in the frequency domain or impulse responses in time domain) that best represent changes in the waveforms for propagation along the surface from source to receiver (303). The prediction uses a mathematical expression, or model, of the earth's filtering effects, both amplitude and phase, as a function of frequency. The desired surface-consistent components are model parameters, and model optimization is used to solve for the surface-consistent components. The surface-consistent components may include filter transfer functions for each source location, each receiver location, and for propagation (302) through each region (301) of the surface that exhibits lateral variation.

Abstract: Method of processing seismic data representative of at least one wavefield, characterized in that local harmonic components of the wavefield are determined at a given point P of the subsurface by implementing a recurrent processing according to which a harmonic of rank n+1, n being a positive integer, is determined as a function of one or more harmonics of rank n or lower to which is applied at least one filtering which depends on at least one local parameter at the point P, this local parameter being chosen from among the components of the wavevector, the frequency of the wavefield, the local velocity, the local anisotropy parameters or any combination of these various parameters.

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: An exemplary method for filtering multi-component seismic data is provided. The exemplary method comprises identifying a plurality of characteristics of the seismic data, the plurality of characteristics corresponding to a relative manifestation of surface wave noise on the different components and identifying a time-frequency boundary in the seismic data, the time-frequency boundary delineating portions of the seismic data estimated to contain surface wave noise (302). In addition, the exemplary method comprises creating filtered seismic data (306) by removing portions of the seismic data that correspond to the plurality of characteristics of surface waves and that are within the time-frequency boundary (303).

Abstract: Provided are an apparatus and method for imaging the subsurface structure of a target area by using waveform inversion. In the apparatus and method, the subsurface structure of a target area is estimated using waveform inversion of a seismic signal in the frequency domain, the Laplace domain, or the Laplace-Fourier domain, and an objective function is defined by applying a weighting function such that the objective function makes a different contribution for each frequency, each Laplace damping constant, or each Laplace-Fourier damping constant. The objective function is not limited to a particular type of objective function and a weighting function can be automatically determined when a gradient vector for each frequency, each Laplace damping constant, or each Laplace-Fourier damping constant is normalized.

Abstract: A method and device for monitoring a subsoil zone, wherein a plurality of receivers are arranged on a surface of the soil or near said surface, straight above a geological zone to be monitored, comprising the following steps: generating a set of reference seismic data; recording seismic data by means of said receivers; correlating the seismic data recorded with the reference seismic data; comparing each trace of the correlated data, with correlated traces located in a vicinity of said trace, in order to evaluate a similarity of each correlated trace with the adjacent correlated traces; and, detecting a microseismic event occurring in the subsoil zone by analysing said similarity. The method and device enables real-time monitoring.

Abstract: Systems and methods for monitoring time-dependant subsurface changes from imperfectly repeated data measurements.

Abstract: Filters are applied to seismic signals representative of subsurface formations to generate filtered signals with attenuated spatially aliased energy. The filtered signals are multiplied in the frequency-wavenumber domain by a complex function of frequency and wavenumber representing the seismic attribute in the frequency-wavenumber domain, to generate scaled signals. The scaled signals, transformed to the time-space domain, are divided by the filtered signals in the time-space domain, to a seismic attribute useful for identifying and characterizing the subsurface formations.

Abstract: Improved methods of processing seismic data which comprise amplitude data assembled in the offset-time domain in which primary reflection signals and noise overlap are provided for. The methods include the step of enhancing the separation between primary reflection signals and coherent noise by transforming the assembled data from the offset-time domain to the time-slowness domain. More specifically, the assembled amplitude data are transformed from the offset-time domain to the time-slowness domain using a Radon transformation according to an index j of the slowness set and a sampling variable ?p; wherein j = p max - p min + 1 ? ? µ ? ? sec ? / ? m ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m, pmax is a predetermined maximum slowness, and pmin is a predetermined minimum slowness. Alternately, an offset weighting factor xn is applied to the assembled amplitude data, wherein 0<n<1, and the amplitude data are transformed with a Radon transformation.

Abstract: Implementations of various technologies for a method for generating a seismic image of a subsurface are described herein. Seismic data may be received from two sensors in a seismic survey. The seismic data below and equal to a predetermined frequency may be classified as low-frequency seismic data. The low-frequency seismic data may be re-sampled based on the predetermined frequency. A set of low-frequency Green's functions may be calculated using interferometry on the re-sampled low-frequency seismic data. High-frequency seismic data of the seismic data may be processed to create a set of high-frequency Green's functions at one or more source locations of the seismic survey. The set of high-frequency Green's functions may be merged with the set of low-frequency Green's functions to create a set of broad-band Green's functions. The seismic image may be generated using the set of broad-band Green's functions at the source locations.

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 includes: interpolating a set of crossline seismic data from a set of acquired multicomponent seismic data; predicting a multiple in the interpolated and acquired seismic data from the combined interpolated and acquired multicomponent seismic data; and suppressing the predicted multiple. Other aspects include a program storage medium encoded with instructions that, when executed by a computing device, perform such a method and a computing apparatus programmed to perform such a method.

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: Seismic image filtering machines, systems, program products, and computer implemented methods are provided to generate a filtered seismic image responsive to filtered seismic image data generated by attenuating coherent seismic noise from surface waves of an unfiltered wavefield constructed from unfiltered seismic image data through a single downward extrapolation of the unfiltered wavefield using a plurality of nonstationary convolution operators to perform localized filtering at each of a plurality of spatial locations of the unfiltered wavefield. Various embodiments, for example, can beneficially handle strong lateral velocity variations thus making various embodiments effective tools to remove complicated coherent seismic noise which is typically in the form of exponentially decaying evanescent waves.

Abstract: A method for estimating seismic data from sources of noise in the earth surrounding a first seismic receiver and a second seismic receiver. The method includes calculating a Green's function G?(X1, X2) between a first seismic receiver X1 and a second seismic receiver X2 using interferometry. The first seismic receiver X1 is located at a distance away from the second seismic receiver X2. After calculating the Green's function G?(X1, X2), the method may include steps for determining an estimate of one or more non-physical wavefields present in the Green's function G?(X1, X2) and determining a filter to remove the non-physical wavefields from the Green's function G?(X1, X2) based on the estimate of the non-physical wavefields. The filter may then be applied to the Green's function G?(X1, X2) to obtain a Green's function G?(X1, X2) free of non-physical wavefields.

Abstract: A method for data processing includes transforming measurement data acquired in the time domain during an oilfield operation into a second domain to produce transformed data; identifying distortions in the transformed data; removing the distortions from the transformed data; and transforming back from the second domain to the time domain to produce cleaned-up data. The transforming measurement data may use a Fourier transform or a wavelet transform. The method may further include compressing the cleaned-up data or reconstructing signals from the cleaned-up data. A method for data processing includes decomposing measurement data, which are acquired in an oilfield operation, using a low pass filter to produce a first dataset; decomposing the measurement data using a high pass filter to produce a second dataset; removing distortions from the second dataset to yield a corrected second dataset; and reconstructing a corrected dataset from the first dataset and the corrected second dataset.

Abstract: A method waveform processing technique utilizing signal coherence of the array data for processing signals having poor signal-to-noise ratio. Raw waveform data is first transformed into f-k (frequency-wavenumber) domain. A coherence function is then calculated and convolved with the data in the f-k domain, which effectively suppresses non-coherent signals in the data. For the remaining coherent data, the unwanted part is muted and the wanted part is retained and inverse-transformed to yield the coherence-filtered array waveform data. After this processing, small signals that are hidden in the original data are extracted with much enhanced coherence. Subsequent processing of the data yields reliable information about formation acoustic property.

Abstract: A statistical value update unit calculates the fluctuation of measurement data. A filtering processing unit extracts a normal white noise component from the fluctuation of the measurement data using an adaptive lattice filter. A statistical test unit determines whether or not the variance of the normal white noise component is out of a predetermined scope in reference distribution. A change decision unit detects a stationary change of the status of a target system based on a detection ratio of an outlier.

Abstract: Improved methods of processing seismic data which comprise amplitude data assembled in the offset-time domain in which primary reflection signals and noise overlap are provided for. The methods include the step of enhancing the separation between primary reflection signals and coherent noise by transforming the assembled data from the offset-time domain to the time-slowness domain. More specifically, the assembled amplitude data are transformed from the offset-time domain to the time-slowness domain using a Radon transformation according to an index j of the slowness set and a sampling variable ?p; wherein j = p max - p min + 1 ? ? µ ? ? sec ? / ? m ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m, pmax is a predetermined maximum slowness, and pmin is a predetermined minimum slowness. Alternately, an offset weighting factor xn is applied to the assembled amplitude data, wherein 0<n<1, and the amplitude data are transformed with a Radon transformation.

Abstract: Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. Assembled seismic data are transformed from the offset-time domain to the time-slowness domain using a Radon transformation. Preferably, the Radon transformation is applied within defined slowness limits pmin and pmax that will preserve coherent noise, and according to an index j of the slowness set and a sampling variable ?p; wherein j = p ma ? ? x - p m ? ? i ? ? n + 1 ? ?sec ? / ? m ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m. The coherent noise content of the transformed data is then enhanced, and the primary reflection signal content diminished by filtering at least a subset of the transformed data.

Abstract: Various methods are disclosed for identifying faults in a seismic data volume. In some method embodiments, the fault identification method comprises determining a planarity value for each of multiple positions of an analysis window in the data volume. The planarity value may be indicative of the planarity of discontinuities in the analysis window, and may be further filtered by limits on the verticality and centrality of the discontinuities. Thus a filter may be determined for suppressing relatively non-planar, relatively non-vertical, and relatively un-centered discontinuities from a discontinuity display, thereby enhancing a display of faults present in the seismic data volume.

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: Improved methods of processing seismic data which comprise amplitude data assembled in the offset-time domain in which primary reflection signals and noise overlap are provided for. The methods include the step of enhancing the separation between primary reflection signals and coherent noise by transforming the assembled data from the offset-time domain to the time-slowness domain. More specifically, the assembled amplitude data are transformed from the offset-time domain to the time-slowness domain using a Radon transformation according to an index j of the slowness set and a sampling variable ?p; wherein j = p max - p min + 1 ? ? ? ? ? sec ? / ? m ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m, pmax is a predetermined maximum slowness, and pmin is a predetermined minimum slowness. Alternately, an offset weighting factor xn is applied to the assembled amplitude data, wherein 0<n<1, and the amplitude data are transformed with a Radon transformation.

Abstract: Methods and apparatus for removing noise from signal traces collected during a seismic gather, particularly removing the aliased energy in the time-slowness (tau-P) domain so that aliasing noise does not lead to high noise levels in the inverse transformed data are provided. Removal of the aliasing noise may provide for quieter seismic traces and may increase the likelihood for successful three-dimensional (3-D) tau-P interpolation and detection of seismic events.

Abstract: Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. Assembled seismic data are transformed from the offset-time domain to the time-slowness domain using a Radon transformation. Preferably, an offset weighting factor xn is applied to the amplitude data, wherein 0<n<1, and the Radon transformation is applied within defined slowness limits pmin and pmax that will preserve coherent noise, and according to an index j of the slowness set and a sampling variable ?p; wherein j = p max - p min + 1 ? ? µ ? ? sec ? / ? m ? ? ? p , ?p is from about 0.5 to about 4.0 ?sec/m. The coherent noise content of the transformed data is then enhanced, and the primary reflection signal content diminished by filtering at least a subset of the transformed data.

Abstract: The propagation of a compressional wave in a reservoir rock causes the pore fluids to flow within the pores and pore connections; this internal flow of the pore fluid exhibits hysteretic and viscoelastic behavior. This nonlinear behavior is directly related to the viscosity of the pore fluids. Pore fluids that have higher viscosity like oil, after being disturbed due to a sudden change in pressure applied by a seismic impulse, require a larger time-constant to return to its original state of equilibrium. This larger time-constant generates lower seismic frequencies, and becomes the differentiating characteristic on a seismic image between the lower-viscosity pore fluid like water against the higher-viscosity pore fluid like oil. Mapping these lower frequencies on a seismic reflection image highlights the oil-bearing volume of the reservoir rock formations versus the volume of the reservoir rock formations saturated with water or gas.

Abstract: A method determining a calibration filter to calibrate a first component of multi-component seismic data relative to a second component of the seismic data comprises determining the calibration filter from a portion of the seismic data that contains only events arising from critical refraction of seismic energy. The method is particularly suitable for long-off-set data, since the first arrival will be a critical refraction event and an automatic picking method may be used. The present invention also provides a wavenumber dependent calibration filter that is obtained from a calibration filter obtained from data in one offset range and another calibration filter obtained from data in another offset range.

Abstract: A method for spectrally conditioning surface seismic data. In one implementation, the method may include correcting surface seismic data for distortions due to anomalous spectral amplitudes, thereby generating a first set of corrected data; correcting the first set of corrected data for deterministic distortions, thereby generating a second set of corrected data; correcting the second set of corrected data for spectral distortions due to the seismic waves traveling through the near-surface, thereby generating a third set of corrected data; and correcting the third set of corrected data for spectral distortions due to the seismic waves traveling through deeper strata.

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 method is disclosed for combining seismic data sets. This method has application in merging data sets of different vintages, merging data sets collected using different acquisition technologies, and merging data sets acquired using different types of sensors, for example merging hydrophone and geophone measurements in ocean bottom seismic data.

Abstract: Methods and related systems are described for processing surface seismic data. Surface seismic data representing seismic signals detected at a plurality of surface locations is wavefield deconvolved using a combination of direct wave travel times estimated from borehole seismic data, and wavefield energy estimated from the surface seismic data.

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: A method and apparatus for a method for generating an estimated value of absorption parameter Q(t). In one embodiment, the method includes receiving an input seismic trace, applying a time variant Fourier transform to the input seismic trace to generate a time variant amplitude spectrum of the input seismic trace, dividing the natural logarithm of the time variant amplitude spectrum by ??f, and performing a power series approximation to the result with an index starting from one to generate an estimated value of R(t). R(t) is a ratio between traveltime t and the absorption parameter Q(t). The method further includes dividing t by R(t) to generate the estimated value of the absorption parameter Q(t).

Abstract: A method and apparatus for correcting an input seismic trace. The method includes receiving the input seismic trace and creating a t by Q gather using the input seismic trace, where t represents traveltime, Q represents absorption parameter, and the t by Q gather has traveltime as the vertical axis and a ratio of t and Q as the horizontal axis. The ratio of t and Q is referred to as R. The method further includes applying an interpolation algorithm to the t by Q gather to derive a corrected input seismic trace.

Abstract: The disclosure describes a method and apparatus for effectively communicating data along an acoustic transmission path. The method comprises driving an acoustic transmitter to send a data signal along the acoustic transmission path, where the signal is distorted by ambient noise. The distorted signal is input to a spaced apart plurality of sensors so that consequent time-delayed signals provide reinforcement of the basic signal and attenuation of the ambient noise component when combined.

Abstract: A method and apparatus for seismic trace matching to well logs.

Abstract: A method of filtering out pressure noise generated by one or more piston pumps, where each pump is connected to a common downstream piping system, and where the discharge pressure is measured by a pressure sensitive gauge, wherein the instantaneous angular position(s) of the pump(s)' crankshaft or actuating cam is/are measured simultaneously with the discharge pressure and used as fundamental variables in an adaptive mathematical noise model.

Abstract: The present invention is a method of processing seismic data in which one or more seismic vibrators are activated with one or more pilot signals and vibrator motions are recorded along with seismic data. Vibrator signatures are computed from measured vibrator motions, such as the ground force signal. A desired impulse response is specified from either a measured vibrator motion or from test data or field data from a location near the location from which the seismic data was acquired. A deconvolution filter is computed from the impulse response and the vibrator signature. Alternatively, a single separation and deconvolution filter is derived from the impulse response and from vibrator signatures from multiple vibrators and sweeps. The deconvolution or deconvolution and separation filter is used to process the seismic data. The vibrators are then moved to a new location, and the activation is repeated.

Abstract: Coherent wave noise energy is removed from seismic data by modeling both the P-wave primary energy and the coherent wave noise energy. The P-wave primary energy is modeled first and then subtracted from the input data. The data with the P-wave primary energy removed is used as the input for coherent wave energy removal. The coherent wave energy is modeled and subtracted from the original input data, i.e. the data input into P-wave primary removal. This leaves a dataset with P-wave primary energy and noise energy not related to coherent waves. This method can be utilized to remove all types of coherent noise with a velocity difference to the desired P-wave primary energy or with a different type of moveout (change of time of arrival with source-receiver distance) such as, for example, linear moveout.