Abstract: A method for enhancing downhole telemetry performance comprising enhancing a signal in order to offset signal-to-noise ratio reduction with increasing measured depth, wherein the signal is modified at specified measured depths which are inferred from acoustic wave velocity determination.

Abstract: The present invention relates to a method and system for processing time-varying three-component signals to determine polarization dependent features therefrom. Relation data indicative of a predetermined expression relating ellipse elements describing an ellipse in three dimensional space to the components of the three-component signal are provided. Received signal data indicative of a three-component signal are processed for transforming each component of the three-component signal into time-frequency domain providing second signal data. Data indicative of polarization dependent features are then determined using the relation data and the second signal data. The method and system for processing time-varying three-component signals according to the invention are highly beneficial in numerous applications for evaluating three-component signal data such as seismology.

Abstract: A seismic source signal generator includes a mass, a primary accumulator and a secondary accumulator, the secondary accumulator having an internal volume smaller than an internal volume of the primary accumulator. A method for generating a signal using a seismic vibrator includes operating the seismic vibrator using hydraulic fluid, damping hydraulic pressure deviations in the hydraulic fluid using a first accumulator in hydraulic communication with the hydraulic fluid, and damping pressure deviations in the hydraulic fluid using a second accumulator in hydraulic communication with the hydraulic fluid, the second accumulator having an internal volume smaller than an internal volume of the first accumulator.

Abstract: Techniques and a system for performing geological interpretation operations in support of energy resources exploration and production perform well log correlation operations for generating a set of graphical data describing the predetermined geological region. The process and system interpret the geological environment of the predetermined geological region from measured surface and fault data associated with the predetermined geological region. Allowing the user to query and filter graphical data representing the predetermined geological region, the method and system present manipulable three-dimensional geological interpretations of two-dimensional geological data relating to the predetermined geological region and provide displays of base map features associated with the predetermined geological region.

Abstract: A method is disclosed that uses (a) source-receiver reciprocity and (b) a method such as ISR DMO (U.S. Patent Application Publication No. 2006/0098529) that allows reconstruction of densely sampled gathers at arbitrary surface locations, to efficiently predict multiple reflections, either surface related or interbed multiples, in seismic data. For each reconstructed gather and each output (field) trace, two traces are extracted corresponding to the field source and receiver positions of the output trace, then they are convolved and the convolution result is added (summed) to that obtained by applying this procedure to previously reconstructed gathers. The efficiency results from the fact that the convolutions are performed by looping over all traces for each “bounce” point, with the outer loop being over bounce points. Once all the reconstructed gathers are processed, multiple predictions are obtained for the whole survey by conventional means.

Abstract: A best fitting trace in seismic data is determined for a desired trace to be reconstructed. A dip-based correction is calculated per trace and per sample for differences in azimuth, common midpoint coordinates, and offset between the best fitting trace and the desired trace. The dip-based correction is applied to the best fitting trace to reconstruct the desired trace for 3D surface-related multiple prediction.

Abstract: A technique includes receiving seismic data indicative of measurements acquired by seismic sensors. The measurements are associated with a measurement noise. The technique includes estimating at least one characteristic of the measurement noise and deghosting the seismic data based at least in part on the estimated characteristic(s) of the measurement noise.

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: Methods, systems, and software for representing seismic shot or receiver data as a superposition of a plurality of diplets are disclosed. The method includes decomposing one or more prestack shot or receiver records into a set of diplets, migrating the diplets using one or more velocity models, and synthesizing one or more migrated diplets into a migrated seismic volume, wherein each diplet comprises information about spatial location, orientation, amplitude, an associated wavelet, acquisition configuration, and coherency.

Abstract: A method is presented for processing an image of a two-dimensional (2D) matrix symbol having a plurality of data modules and a discontinuous finder pattern, each distorted by “donut effects”. A resulting processed image contains an image of the 2D matrix symbol having a continuous finder pattern suitable for conventional 2D matrix symbol locating techniques, and having a plurality of data modules, each data module having a center more truly representative of intended data, and suitable for conventional 2D matrix symbol sampling and decoding. The method includes sharpening the distorted image of the 2D matrix symbol to increase a difference between low frequency and high frequency image feature magnitudes, thereby providing a sharpened image, and smoothing the sharpened image using a moving window over the sharpened image so as to provide a smoothed image, the moving window and a module of the 2D matrix code being of substantially similar size.

Abstract: A method for mapping sub-surface resistivity contrasts comprising making multi-channel transient electromagnetic (MTEM) measurements using at least one electric source with grounded input current electrodes or one magnetic source with current in a wire loop or multi loop and at least one electric field or magnetic field receiver, measuring the resultant earth response simultaneously at each receiver using a known recording system, measuring the system response by measuring directly the current in the wire at the source using effectively the same recording system, using the measured system response to recover the impulse response of the earth from each measured earth response, and creating from such impulse responses a sub-surface representation of resistivity contrasts.

Abstract: A calculated vertical velocity sensor signal is determined from a recorded pressure sensor signal. A constructed vertical velocity sensor signal is determined as a linear combination of the calculated vertical velocity sensor signal and a recorded vertical velocity sensor signal in dual-sensor seismic streamer data, using a mixture coefficient as a proportionality constant. An upgoing pressure wavefield component is determined as one half of a difference of the recorded pressure sensor signal and the constructed vertical velocity sensor signal, as a function of the mixture coefficient. An error in the upgoing pressure wavefield component is determined by propagating errors in the recorded pressure sensor signal and constructed vertical velocity sensor signal terms. A value of the mixture coefficient is determined that minimizes the error in the upgoing pressure wavefield component.

Abstract: A method for determining upgoing pressure components of seismic signals from signals detected by combined pressure responsive sensors and motion responsive seismic sensors disposed in a plurality of laterally spaced apart streamers includes determining a threshold time at which angle of incidence error in the motion responsive signals in the cross-line direction falls below a selected threshold. Below the threshold time, the motion responsive signals are corrected for angle of incidence in the in-line and cross-line directions. Above the threshold time, the motion responsive signals are corrected for angle of incidence only in the in-line direction. Both sets of incidence corrected measured motion responsive signals, and the pressure responsive signals are used to determine upgoing or downgoing pressure components or upgoing or downgoing motion components of the measured motion responsive and pressure responsive seismic signals.

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: Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. The methods comprise the steps of assembling seismic data into common geometry gathers in an offset-time domain without correcting the data for normal moveout. The amplitude data are then transformed from the offset-time domain to the time-slowness domain using a limited Radon transformation. That is, the Radon transformation is applied within defined slowness limits pmin and pmax, where pmin is a predetermined minimum slowness and pmax is a predetermined maximum slowness. A corrective filter is then applied to the transformed data enhance the primary reflection signal content of the data and to eliminate unwanted noise events. After filtering, the enhanced signal content is inverse transformed from the time-slowness domain back to the offset-time domain using an inverse Radon transformation.

Abstract: Methods and apparatus are described for measuring noise in video image processing. The described methods use horizontal and vertical variances of pixels of an image to extract noise information from the image. Silent regions in an image are considered to determine amplitude variations in the image. A smallest silent region in the image is searched by performing measurements over various block sizes. A least sum of absolute differences approach is used on both horizontal and vertical directions for finding the minimum energy of a received image signal. Using the disclosed method and processor, with a Gaussian distribution for the measured channel noise, both silent image regions, as well as edges, are equally covered.

Abstract: Methods, systems, and software for generating a multi-dimensional volume are disclosed. The methods include decomposing one or more original volumes into a collection of diplets, wherein each diplet includes information about spatial location, orientation, amplitude, wavelet, acquisition configuration, and coherency. The methods further include migrating the collection of diplets using one or more of a velocity model or an anisotropic velocity model, and synthesizing one or more of the migrated diplets to an output multi-dimensional seismic volume.

Abstract: To perform noise attenuation for seismic surveying, a sensor assembly is deployed on a ground surface, where the sensor assembly has a seismic sensor to measure seismic waves propagated through a subterranean structure, and a divergence sensor comprising a pressure sensor to measure noise. First data is received from the seismic sensor, and second data is received from the divergence sensor. The first data and the second data are combined to attenuate noise in the first data.

Abstract: Passive seismic data is collected from measurements of seismic sensors in respective sensor assemblies, where the passive seismic data is based on measurements collected during periods when no active seismic source was activated. Attenuation of surface noise in the passive seismic data is performed using data from divergence sensors in at least some of the sensor assemblies. The passive seismic data with surface noise attenuated is output to allow for performing an operation related to a subterranean structure using the passive seismic data with the surface noise attenuated.

Abstract: A system, which may be and/or may include a computer system, and method for identifying a fault patch position from a seismic data volume. The system and method may include defining an initial active surface in the seismic data volume; identifying one or more active surfaces by minimizing the value of a function for energy; tracking back the active surfaces to find a set of control points; and producing the fault patch position formed by the set of control points.

Abstract: The present invention relates to a method of filtering seismic data for noise attenuation. An embodiment of the present invention provides a method of processing seismic data in which the seismic data is transformed into an f-x domain using a discrete Fourier transform and is then filtered at each discrete frequency using an infinite impulse response (HR) filter.

Abstract: A method for processing geophysical data. The method includes generating a model from geophysical data acquired at a receiver location and one or more boundary receiver locations. After generating the model, the method applies a forward modeling algorithm using information from the model to generate a modeled estimate of a direct ground roll between the receiver location and each boundary receiver location. The method then estimates a ground roll between a source location and each boundary receiver location.

Abstract: A seismic streamer includes at least one array of sensors each disposed in a sensor holder at longitudinally spaced apart locations. A longitudinal orientation of at least one sensor or at least one sensor holder is different from that of the other sensors along the length of the array.

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: 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 of modeling seismic wave-field data in order to suppress near-surface and sub-surface related multiple reflection signals is provided. The reflection signals include main primary reflection signals, main random noise signals, main multiple reflection signals, residual primary reflection signals, residual random noise signals, and residual multiple reflection signals. Main random noise signals are separated from the reflection signals using a frequency-wavenumber domain method to provide data having suppressed main random noise. Main primary reflection signals are separated from the data having suppressed main random noise using frequency-wavenumber filtering and weighted median filtering to provide data having suppressed main random noise and main primary reflections. Multiple reflection signals are modeled using parabolic path summation on the data having suppressed main random noise and main primary reflections.

Abstract: A method of pre-stack two-dimension-like transformation of three-dimensional seismic record is accomplished by the following steps: acquiring 3D seismic data, and arranging them according to a shot gather; calculating the offsets of all the receiver points from the first receiver line of the first shot; making a straight line (L2?) which connects the shot point (S) and the receiver point (R1) of the smallest offset as the transformed coordinate axis, and making the shot point (S) as the center, drawing circles whose radii are the offsets (offseti) of each receiver point, then rotating each receiver point to the straight line (L2?), thereby accomplishing the two-dimension-like transformation of all the receiver lines of the shot, and getting three-dimensional seismic data graph with high precision; and then making the processing of the noise elimination and static correction on the three-dimensional seismic record using conventional technique.

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: 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: A method of processing seismic data including pressure data and pressure gradient data to obtain gradients of moveout corrected pressure data, comprising applying a move-out correction function to the pressure gradient data; and adding a correction term dependent on a moveout corrected time-derivative of the pressure data and a spatial derivative of the moveout correction function. The method may be used prior to any data processing algorithm which uses pressure gradient data in which moveout correction is applied prior to the algorithm, either because the algorithm makes a zero offset assumption or because it is beneficial for the algorithm to operate on moveout corrected data to reduce aliasing.

Abstract: Despite full waveform propagation capabilities offered by reverse time migration or inversion, prior art methods can generate spurious events from multiples and therefore are limited to using data without free-surface multiples. By eliminating or largely reducing artificial transmission of multiples, the enhanced reverse time migration or inversion in the present invention can correctly use data that contain free-surface and internal multiples and improve image quality or properties estimation.

Abstract: Techniques are disclosed for determining the bearing from a three-axis geophone to a seismic source, such as a person or other man-made seismic source. In one embodiment, the techniques are implemented as a method that includes receiving outputs from a three-axis geophone (x axis, y axis and z axis outputs), computing a magnitude signal based on the x and y axis outputs, determining locations of each local peak in the magnitude signal, computing a bearing estimate for each peak, and computing a median of the bearing estimates. The resulting median bearing is an estimate of the bearing from the geophone to a target seismic source. In one such case, computing the magnitude signal based on the x and y axis outputs is performed in response to detecting the target seismic source in the phase-shifted z axis output.

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: Method for detecting and/or processing seismic signals, for example acoustic and/or elastic waves, generated by a plurality of seismic and/or acoustic sources and acquired by a plurality of seismic and/or acoustic sensors disposed in/on the subsurface, which provides at least a step in which at least a convolution operation is performed, applied to the seismic signals, having an orientation concordant with the orientation of the time axis, to obtain a signal assimilable to a seismic signal reflected by a reflector element disposed in correspondence with the seismic and/or acoustic sensors of the seismic and/or acoustic sources.

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: Embodiments are directed to systems and methods (200, 300) that enable spatial variability of surface waves to be accounted for in dispersion correction in seismic data processing. This yields superior surface wave noise mitigation, with reduced likelihood of attenuating signal. Embodiments are operative with spatially inhomogeneous media.

Abstract: Embodiments use seismic processing methods that account for the spatial variability of surface wave velocities. Embodiments analyze surface wave properties by rapidly characterizing spatial variability of the surface waves in the seismic survey data (302). Filtering criteria are formed using the spatial variability of the surface waves (204). The filtering criteria can then be used to remove at least a portion of the surface waves from the seismic data (206, 319). The rapid characterization involves estimating a local group velocity of the surface waves by cross-correlation of the analytic signals (302).

Abstract: A method for enhancing downhole telemetry performance comprising enhancing a signal in order to offset signal-to-noise ratio reduction with increasing measured depth, wherein the signal is modified at specified measured depths which are inferred from acoustic wave velocity determination.

Abstract: Systems and methods in which data compression techniques are utilized to fill a predetermined channel capacity are shown. According to one configuration, event data points within test data are selected for communication via the data communication channel and a data decimator is utilized to identify other data points within the test data to fill or substantially fill the predetermined channel capacity. The foregoing data decimator may employ one or more variables for selecting data for communication, wherein one or more of the variables are preferably adjusted in decimator iterations to select an optimum or otherwise desirable subset of data for communication. Data decimators may additionally or alternatively implement a suitable “growth” function to select the particular data for communication and/or the amount of data communicated.

Abstract: Methods and apparatus are provided for generating velocity models for pre-stack depth migration (“PSDM”). Seismic, gravity and electromagnetic joint inversion input data are generated based on observed seismic, gravity and electromagnetic data (e.g., magnetotelluric and/or controlled source electromagnetic), and velocity, density and resistivity models. A joint inversion is performed to produce a multiparametric model that is a function of velocity, density and resistivity parameter distributions. The separate parameter distributions are extracted from the multiparametric model, and the extracted velocity model is used to perform a PSDM. A migration velocity analysis is performed on PSDM output to generate seismic image residuals. If the seismic image residuals meet predetermined quality objectives, the extracted velocity model is output as the final velocity model for PSDM.

Abstract: The present invention relates to methods for data processing, particularly seismic data represented in three dimensions (3D). A method in accordance with one embodiment of the invention includes identifying extrema points from the 3D seismic data set; removing artificial distortion from 3D seismic data set; generating extrema cubes and derivatives along extrema points; estimating a class number associated with the extrema points; and determining number of classes and dynamically classifying extrema points.

Abstract: Coherency analysis, such as semblance scan or stacking amplitude, is used to locate diffractors. Once the diffractors are located, noise energy originating from the diffractors is minimized. Locations of each diffractor are determined by comparing the lateral coherency of the received amplitudes that each assumed diffractor position generates.

Abstract: A method whereby a downhole drilling transmission device that communicates to the surface automatically modifies its transmission parameters in order that it substantially improves its ability to adequately communicate with a surface receiver despite increasing signal attenuation between the two as the length of drillpipe increases. This utilizes a simple measure of localized downhole pressure that then relies upon a look-up table or similar that provides a correspondence between said pressure and measured depth. Such a look-up table or similar can be readily built by incorporating appropriate features of the planned well such as drilling fluid flow rate, drilling fluid density, drilling fluid viscosity, well profile, bottom hole assembly component geometry, drillpipe geometry, and indications as to whether the fluid is flowing or stationary.

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: A method and system for processing synchronous array seismic data includes acquiring synchronous passive seismic data from a plurality of sensors to obtain synchronized array measurements. A reverse-time data process is applied to the synchronized array measurements to obtain a plurality of dynamic particle parameters associated with subsurface locations. These dynamic particle parameters are stored in a form for display. Maximum values of the dynamic particle parameters may be interpreted as reservoir locations. The dynamic particle parameters may be particle displacement values, particle velocity values, particle acceleration values or particle pressure values. The sensors may be three-component sensors. Zero-phase frequency filtering of different ranges of interest may be applied. The data may be resampled to facilitate efficient data processing.

Abstract: We here disclose methods of imaging multishot data without decoding. The end products of seismic data acquisition and processing are images of the subsurface. When seismic data are acquired based on the concept of multishooting (i.e., several seismic sources are exploited simultaneously or near simultaneously and the resulting pressure changes or ground motions are recorded simultaneously there are two possible ways to obtain images of the subsurface. One way consists of decoding multishot data before imaging them that is the multishot data are first converted to a new dataset corresponding to the standard acquisition technique in which one single shot at a time is generated and acquired and then second imaging algorithms are applied to the new dataset. Actually all seismic data processing packages available today require that multishot data be decoded before imaging them because they all assume that data have been collected sequentially.

Abstract: A method and system for processing synchronous array seismic data includes acquiring synchronous passive seismic data from a plurality of sensors to obtain synchronized array measurements. A reverse-time data process is applied to the synchronized array measurements to obtain a plurality of dynamic particle parameters associated with subsurface locations. These dynamic particle parameters are stored in a form for display. Maximum values of the dynamic particle parameters may be interpreted as reservoir locations. The dynamic particle parameters may be particle displacement values, particle velocity values, particle acceleration values or particle pressure values. The sensors may be three-component sensors. Zero-phase frequency filtering of different ranges of interest may be applied. The data may be resampled to facilitate efficient data processing.

Abstract: It is described a method for spatially filtering 3D seabed seismic data acquired in a cross-line geometry including methods of how to decompose the data using a filter with two spatial components.

Abstract: A method and system of detecting and mapping a subsurface hydrocarbon reservoir includes determining ratio data for a plurality of orthogonal spectral components of naturally occurring low frequency background seismic data. The ratio data may be compared, plotted, contoured and displayed as a subsurface hydrocarbon reservoir map or a hydrocarbon potential map. The ratio data may represent a vertical spectral component of the seismic data over a horizontal spectral component of the seismic data. The subsurface hydrocarbon reservoir map may include contouring the ratio data over a geographical area associated with the seismic data.

Abstract: According to a first preferred aspect of the instant invention, there is provided an efficient method of computing a 3D frequency domain waveform inversion based on 3D time domain modeling. In the preferred arrangement, 3D frequency domain wavefields are computed using 3D time-domain modeling and a discrete Fourier transformation that is preferably computed “on the fly” instead of solving the large systems of linear equations that have traditionally been required by direct frequency domain modeling. The instant invention makes use of the theory of gradient-based waveform inversion that estimates model parameters (for example velocities) by matching modeled data to field data sets. Preferably the modeled data are calculated using a forward modeling algorithm.