Abstract: Method for processing seismic data. In one implementation, the method includes converting a common midpoint (CMP) gather of seismograms into one or more interferogram common midpoint (ICMP) gathers, generating a semblance spectrum for each ICMP gather, stacking the semblance spectrum from each ICMP gather to generate a combined semblance spectrum and deriving a normal moveout (NMO) velocity profile from the combined semblance spectrum.

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 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 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 to attenuate unwanted signals in seismic data using seismic interferometry techniques. In one implementation, seismograms may be converted into seismic interferograms. In the seismic interferogram domain, unwanted signals may be attenuated by various techniques, such as muting, filtering and the like. The modified seismic interferograms may then be converted back into seismograms with the unwanted signals having been attenuated.

Abstract: Correcting seismograms to compensate for absorption or dissipative effects that occur in the earth. In one implementation, a ratio of traveltime (t) to absorption parameter (Q) may be computed for each seismogram. The ratio may be referred to as R. Further, the ratio may be computed for a predetermined set of traveltimes. As a result, a system of linear equations may be generated, where each ratio is represented by a linear equation having a number of unknown components. The system of linear equations may then be solved for the unknown components. The solved components may then be recombined or added to generate an estimate of R. In one implementation, only a portion of the solved components may be added. The seismograms may then be corrected using the estimate of R. As such, the seismograms may be corrected for absorption effects in a surface consistent manner.

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: Method for estimating one or more ray parameters for seismograms. In one implementation, the method may include selecting a reference seismogram from a gather of seismograms, selecting a set of seismograms neighboring the reference seismogram, generating a set of seismic interferograms from the reference seismogram and the selected set of seismograms, slant stacking the set of seismic interferograms to generate a ray parameter seismic interferogram corresponding to the reference seismogram and estimating a ray parameter from the ray parameter seismic interferogram.

Abstract: The technologies described herein include systems and methods for reducing noise in seismic data. More specifically, implementations may determine an amount of over-sampling for a frequency range of seismic data. Then, implementations may determine frequency bands based on the over-sampling. For each frequency band minimum-noise seismograms may be selected from consecutively occurring blocks of seismograms, and the remaining seismograms within each block may be discarded. The minimum-noise seismograms may then be used to reconstruct the discarded seismograms. The reconstructed seismograms may contain less noise than the original seismograms and, consequently, the seismic data may contain less noise.

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: Method for determining acceptability of sensor locations used to perform a seismic survey. In one implementation, the method includes obtaining a first set of reference data, generating a first output trace from a second set of reference data estimated from the first set of reference data at a plurality of planned sensor locations, generating a second output trace from a third set of reference data estimated at a plurality of actual sensor locations and comparing the second output trace with the first output trace to determine whether the variation between the second output trace and the first output trace is less than a predetermined value.

Abstract: Method for processing seismic data. In one implementation, the method includes converting a common midpoint (CMP) gather of seismograms into one or more interferogram common midpoint (ICMP) gathers, generating a semblance spectrum for each ICMP gather, stacking the semblance spectrum from each ICMP gather to generate a combined semblance spectrum and deriving a normal moveout (NMO) velocity profile from the combined semblance spectrum.

Abstract: Method for correcting seismograms to compensate for absorption effects that occur in the earth. In one implementation, the method may include computing a ratio of traveltime to absorption parameter for each seismogram to generate a system of linear equations. The ratio is expressed as a linear equation having a plurality of components. The method may further include solving the system of linear equations for the plurality of components, adding one or more of the solved components to generate an estimate of the ratio of traveltime to absorption parameter, and correcting the seismograms using the estimate of the ratio of traveltime to absorption parameter.

Abstract: A method of processing seismic data including convolving at least first and second seismic data traces or respective portions of at least first and second seismic data traces to forma composite trace. The travel time of an event may then be determined in the composite trace. This provides an improved method compared to the prior art technique of picking the travel time of an event individually in each one of a number of seismic data traces and averaging the individual picked travel times.

Abstract: Method for processing seismic data. In one implementation, the method includes converting a common midpoint (CMP) gather of seismograms into one or more interferogram common midpoint (ICMP) gathers, generating a semblance spectrum for each ICMP gather, stacking the semblance spectrum from each ICMP gather to generate a combined semblance spectrum and deriving a normal moveout (NMO) velocity profile from the combined semblance spectrum.

Abstract: Implementations described herein provide methods and devices for interpolating or estimating data from previously acquired data. Furthermore, implementations described herein calculate optimum interpolation operators by maximizing the spatial bandwidth of interpolation operators within a specified acceptable mean square error. According to one implementation, spatial bandwidth may be maximized by selecting a local grid within a global grid having nodes corresponding to desired interpolation locations. According to another implementation, spatial bandwidth may be maximized by specifying maximum wave numbers when calculating interpolation operators.

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: Method for determining acceptability of sensor locations used to perform a seismic survey. In one implementation, the method includes obtaining a first set of reference data, generating a first output trace from a second set of reference data estimated from the first set of reference data at a plurality of planned sensor locations, generating a second output trace from a third set of reference data estimated at a plurality of actual sensor locations and comparing the second output trace with the first output trace to determine whether the variation between the second output trace and the first output trace is less than a predetermined value.

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.