Abstract: A method for performing amplitude variation with offset (AVO) analysis of a plurality of seismic data traces. The method includes fitting at least a two-term AVO equation to at least three seismic data traces having small angles of incidence using a curve fitting technique to generate an AVO intercept and an AVO gradient, computing a plurality of synthetic seismic data traces using the AVO intercept and the AVO gradient, subtracting the synthetic seismic traces from the plurality of seismic data traces to generate a plurality of higher-order seismic data traces characterized by a residual AVO equation, and fitting the residual AVO equation to the higher order seismic data traces having large angles of incidence using the curve fitting technique to generate a higher order AVO attribute.

Abstract: A method is disclosed for identifying zones anomalously absorptive of seismic energy. The method includes jointly time-frequency decomposing seismic traces, low frequency bandpass filtering the decomposed traces to determine a general trend of mean frequency and bandwidth of the seismic traces, and high frequency bandpass filtering the decomposed traces to determine local variations in the mean frequency and bandwidth of the seismic traces. Anomalous zones are determined where there is difference between the general trend and the local variations.

Abstract: A method of analyzing seismic survey data in which a transfer function for a geological model is derived by ray tracing techniques applied to theoretical data and the transfer function is applied to actual survey data in order to calculate reflection points (50) and/or other attributes for each shot (42)/receiver (44) pair. The number of ray tracing calculations which have to be performed in deriving the model transfer function can thus be controlled. A sufficiently accurate transfer function can be derived using theoretical data representing substantially fewer shot (42)/receiver (44) pairs than are used in the traditional ray tracing solution applied directly to actual survey data. Attribute values for actual source (42)/receiver (44) pairs are estimated by interpolating the transfer function data.

Abstract: A method of determination of fluid pressures in a subsurface region of the earth uses seismic velocities and calibrations relating the seismic velocities to the effective stress on the subsurface sediments. The seismic velocities may be keyed to defined seismic horizons and may be obtained from many methods, including velocity spectra, post-stack inversion, pre-stack inversion, VSP or tomography. Overburden stresses may be obtained from density logs, relations between density and velocity, or from inversion of potential fields data. The seismic data may be P-P, P-S, or S-S data. The calibrations may be predetermined or may be derived from well information including well logs and well pressure measurements. The calibrations may also include the effect of unloading. The determined pressures may be used in the analysis of fluid flow in reservoirs, basin and prospect modeling and in fault integrity analysis.

Abstract: A method of determining a fluid property in a subsurface region of interest of an earth formation uses measurements of seismic attributes on seismic data. For a test region, a plurality of realizations of rock properties are specified, and for each of the realizations and a selected value of a fluid property, the seismic attribute is modeled. This defines a probability density function (PDF). Comparison of the PDF of the model output with the PDF on the measured seismic data is used to determine the likelihood of the selected fluid property.

Abstract: A method for the design of VSP surveys for the purpose of imaging a reef in the formations surrounding the well in question. The basic steps include: building a geophysical model; defining receiver locations in the well within the model; defining the target (reef); ray tracing from receivers to surface via target; defining source locations on surface based on ray density pattern; and validate by ray tracing from source locations to receiver locations via target.

Abstract: Measurements made by a cross-dipole acoustic logging tool in a borehole are processed to determine the principal directions of azimuthal anisotropy of a subsurface formation. Measurements indicative of azimuthal resistivity variations are also made with a multicomponent induction logging tool. These electrical measurements are processed using the principal direction determined from acoustic measurements to give an estimate of azimuthal resistivity variations. Based on modeling results, azimuthal resistivity variations are interpreted to estimate a fracture depth in the rock for known fluids therein.

Abstract: The invention is a method for determining the orientation of a multi-component receiver where the preferred embodiment of the method makes use of an approximation of the relative bearing angle provided by a relative bearing sensor. The method comprises the steps of scanning various angles around the approximated relative bearing angle provided by the relative bearing sensor and for each scanned angle rotating the data into the true earth frame using a given scanned angle and measuring the polarization angle of the rotated data in the horizontal plane and calculating a weighted sum of the differences between the source azimuth and the estimated azimuth from the polarization.

Abstract: A method of processing seismic data, for example surface seismic data such as multi-component OBC (Ocean Bottom Cable) seismic data, comprises using vertical seismic profile (VSP) seismic data to determine a model of the relationship between depth within the earth and the velocity of seismic energy. In one embodiment, an model of the relationship between depth and velocity of seismic energy for P-waves is calibrated using VSP seismic data. Then, a model of the relationship between depth and velocity of seismic energy for S-waves is calibrated using VSP seismic data. Initially the models are calibrated for the vertical velocity of P-waves and S-waves, using zero-offset or low-offset VSP data. The models may then undergo further calibration steps, such as calibration for VTI anisotropy and anelastic attenuation. Once calibration is complete, the models are used to process surface seismic data.

Abstract: A method for contemporaneously utilizing seismic data in the pre-stack seismic domain and the post-stack seismic domain is disclosed. The method includes initiating a higher order probe at a three-dimensional coordinate in a post-stack seismic volume; and instantiating a pre-stack seismic data content for the higher order probe. In alternative aspects, the invention includes a program storage medium encoded with instructions that, when executed by a computer, perform the method and a computer programmed to perform the method.

Abstract: A new method is presented for generating a probability map, a cutoff map, and a confidence limit map in one single operation. In addition, the new method can also generate a cube representing a cubic volume of earth formation by using the same method for generating the aforementioned maps.

Abstract: A process for displaying seismic data that compares the data to a model function, typically a trigonometric sine wave. Sample points from the model function are compared to sample points of the seismic data at each graphic point being displayed. Seismic sample data for each graphic point, along with seismic data from neighboring graphic points, is correlated to sample data from the model function to produce a regression gradient for the graphic point. The absolute value of the regression gradient is displayed graphically at the graphic point location, using a gray scale. The correlation is performed by regressing the seismic data sample points with sample points from the model function using a least squares technique to determine the regression gradient for the graphic point.

Abstract: A method for making a time-lapse seismic survey in a marine environment, the method designed to eliminate multiple surface reflections and changes in sea state and conditions. Seismic sources and receivers are positioned at predetermined conditions for a first set of data in which at least two sets of seismic signals are recorded at each receiver, proximate in time, such that there are insignificant changes in the subsurface formation. At a later point in time the seismic source(s) and receiver(s) are positioned at the same place when the first seismic data set was generated. A seismic source emits a sound wave and the seismic receiver receives what will be called a “monitor signal” and the two-way water travel time is again determined. A model is then developed for the first and second seismic data sets in that includes the subsurface signal, changes in the subsurface signal and the effect of multiple reflections.

Abstract: A method for determining a velocity model of seismic waves picked up by seismic receivers coupled with an underground formation, in response to the emission of seismic waves in the subsoil by a seismic source, after reflection on geologic interfaces of the formation, from multi-offset records of these waves is disclosed. From picking the seismic records of one or more events for different source-pickup pairs associated with the weakest offset of a seismic acquisition device, the geometry of the events is predicted for the total range of offsets of the acquisition device and for different velocity values taken around a reference layer velocity, by means of kinematic inversion and modelling techniques. Then, for different lateral positions of the acquisition device, the predicted travel time curve best approaching the seismic event considered is selected. The travel times thus obtained are then supplied to a prestack inversion method such as a travel time tomography.

Abstract: A method for tomographic modeling of seismic wave travel times from well drilling records generated by drill string vibrations during drilling and identifying in the recorded vibration at least one of direct, reflected, refracted, converted and diving waves so as to measure wave velocity in near surface layers.

Abstract: A method for performing pre-stack time migration of seismic data in a region where the subsurface seismic wave propagation velocity varies in both the vertical direction and a horizontal direction. The migration is performed in the wave number—frequency domain and involves using travel time maps to find a linear fitting of the migration phase shift for a given ray parameter and at a given vertical depth versus horizontal position. The slope and intercept parameters from the linear fit are used to adjust a known pre-stack time migration equation, with the accuracy of the linear approximation requiring mild horizontal velocity variation.

Abstract: A method of constructing a basis of functions intended for the building of approximations of one-way or two-way seismic traveltime versus offset functions. The method is characterized by the combination of the following steps of (a) creating a distribution of reference one-way or two-way traveltime versus offset functions by traveltime modelling in a set of velocity models representing possible velocity distributions, (b) obtaining new reference functions by modifying these reference traveltime functions by applying an operator to them, (c) selecting a set of discrete offsets to make these new reference functions discrete, (d) arranging these discrete functions in columns to form a matrix, (e) applying a singular value decomposition to this matrix, with singular values sorted in decreasing order, to express its columns as linear combinations of the columns of an orthogonal matrix, and (f) building the basis functions by interpolating the columns of the orthogonal matrix.

Abstract: Method for solving the classical inversion problem of finding the angle dependent reflection coefficients along selected reflectors in the subsurface. The input data to the method include seismic constant offset or constant angle data cubes from Pre-Stack Depth Migration of Kirchhoff type and the corresponding reflectors and velocities from the interpretation and velocity analysis of the data. One or more of the reflectors are chosen and ray modeling is done to create synthetic seismics for all shot/receiver pairs in the seismic survey. Based on these modeling results, amplitude correction maps are made for the various reflection angles. These correction maps are applied to the amplitudes from the seismic data. The corrected amplitudes are approximations to the angle-dependent reflection coefficients in all points on each selected reflector. For each point, a weight function is computed, giving the quantitative resolution of the estimate of the reflection coefficient.

Abstract: A method for performing amplitude variation with offset (AVO) analysis of a plurality of seismic data traces. The method includes fitting at least a two-term AVO equation to at least three seismic data traces having small angles of incidence using a curve fitting technique to generate an AVO intercept and an AVO gradient, computing a plurality of synthetic seismic data traces using the AVO intercept and the AVO gradient, subtracting the synthetic seismic traces from the plurality of seismic data traces to generate a plurality of higher-order seismic data traces characterized by a residual AVO equation, and fitting the residual AVO equation to the higher order seismic data traces having large angles of incidence using the curve fitting technique to generate a higher order AVO attribute.

Abstract: A method for determining a velocity model of seismic waves picked up by seismic receivers coupled with an underground formation, in response to the emission of seismic waves in the subsoil by a seismic source, after reflection on geologic interfaces of the formation, from multi-offset records of these waves is disclosed. From picking the seismic records of one or more events for different source-pickup pairs associated with the weakest offset of a seismic acquisition device, the geometry of the events is predicted for the total range of offsets of the acquisition device and for different velocity values taken around a reference layer velocity, by means of kinematic inversion and modelling techniques. Then, for different lateral positions of the acquisition device, the predicted travel time curve best approaching the seismic event considered is selected. The travel times thus obtained are then supplied to a prestack inversion method such as a travel time tomography.

Abstract: A method of predicting values of formation parameters (e.g., compressional velocity, density, pore pressure, and fracture pressure) as a function of depth includes generating an initial prediction of a profile of the formation parameters and uncertainties associated therewith using information available regarding the formation, obtaining information related to the formation parameters during drilling, and updating the uncertainties as a function of the first prediction and the information obtained in a recursive fashion. Known equations are used for finding initial values, and uncertainties associated therewith are quantified by using probability density functions (PDFs). A Bayesian approach is utilized where “prior PDFs” describe uncertainty prior to obtaining additional information, and “posterior PDFs” account for the additional information acquired. As additional information is acquired while drilling, the posterior PDFs are redefined.

Abstract: A method for enhancing signal-to-noise (S/N) ratio of seismic data is presented. An ensemble of input traces is decomposed into a plurality of frequency bands of traces. Trace and signal power and then a maximum allowable signal-to-noise ratio are estimated for each frequency band. Weights are calculated which are functions of the inverse noise power or rms. The amplitudes in each of the traces are reformed using a fitting function which utilizes the estimated weights to create true relative amplitude signal enhanced traces. The weighting function has data adaptive parameters which can be changed to accommodate noise characteristics such coherency, incoherency, Gaussian and non-Gaussian distributions, etc. The method may be applied across many different coordinate systems. The method may be applied iteratively to seismic data to shape the noise distribution of the seismic data.

Abstract: Seismic imaging apparatus for receiving data propagated through sub-surface structure from a seismic source to at least one seismic receiver and forming an image therefrom, the apparatus comprising: an imager for forming an initial image from said data including initial locations of seismic features indicated in said data, a migrator, associated with said imager, for carrying out seismic migration over at least two layers or depth levels to provide corrections to said initial locations, said migrator comprising a krylov space expander for carrying out a krylov space expansion of the exponent of a square root operator, the operator being for defining a wave propagation between respective layers, and a corrector, for using said corrections with said initial locations to form a seismic image indicating said features.

Abstract: Seismic imaging apparatus for receiving data propagated through sub-surface structure from a seismic source to at least one seismic receiver and forming an image therefrom, the apparatus comprising: an imager for forming an initial image from said data including initial locations of seismic features indicated in said data, a migrator, associated with said imager, for carrying out seismic migration over at least two layers or depth levels to provide corrections to said initial locations, said migrator comprising a krylov space expander for carrying out a krylov space expansion of the exponent of a square root operator, the operator being for defining a wave propagation between respective layers, and a corrector, for using said corrections with said initial locations to form a seismic image indicating said features.

Abstract: A seismic signal is represented as a combination of a geologic signal and a noise signal. The representation of the seismic signal is decomposed into a linear combination of orthonormal components. One or more components are identified in which the geologic signal and the noise signal are uncorrelated. The noise signal is expanded as a product of an unknown noise amplitude modulation signal and a known noise spatial periodicity signal at the identified components. The expansion is solved for an estimate of the noise amplitude modulation signal at the identified components. The noise signal is estimated by multiplying the estimated noise amplitude modulation signal by the noise spatial periodicity signal. The estimated noise signal can be removed from the seismic signal to generate an estimate of the geologic signal.

Abstract: A method of calculating a throw volume corresponding to a seismic data volume. A range of time shifts and a search direction for the seismic data volume are selected. A data location separation and a vertical time window are also selected. A cross-correlation is calculated between data values corresponding to first and second data locations separated by the data location separation and symmetrically located in the search direction on each side of a target data location. The cross-correlation is calculated throughout the vertical time window for each time shift in the range of time shifts. The time shift corresponding to the maximum calculated cross-correlation is stored in the throw volume.

Abstract: Providing a set of seismic sources in a focusing array to enable concentrating seismic energy in a selected target point (k) in an underground formation, by performing a standard seismic survey of the underground formation using a set of impulsive seismic sources and a set of downhole seismic receivers j, and recording the signals uij(t), selecting a position k to be the target point; obtaining from the signals uij(t) the one-way travel times &tgr;ik from a number of sources i to the target point at the location k; and calculating ti=t0−&tgr;ik to obtain the activating times ti at which the impulsive seismic sources i have to be activated, in order to get a focusing array of the seismic sources i of which the seismic waves arrive at the target point k in phase at time t0.

Abstract: A method and system for real time updating of an earth model. The efficiency with which an oil or gas well is constructed can be enhanced by updating the relevant earth model using real-time measurements of the effective density of the drilling fluid and other parameters. The method includes generating an earth model used for predicting potential problems in drilling of a borehole having a predetermined trajectory. Evaluations of the state of the borehole and local geological features are obtained which are based on the earth model. Real time data is used to create a diagnosis of the state of the borehole and local geological features. The evaluations are compared with a diagnosis to identify inconsistencies. A component of the earth model is identified that is both related to the identified inconsistency and has a high degree of uncertainty. The selected component of the earth model is then updated prior to completing construction of the borehole using the received data.

Abstract: A calculating device and method provided for a shaking test apparatus for carrying out a shaking test on a structure by using a partial structure and a numerical model which is virtually connected to the partial structure. The calculating device includes a calculation part which identifies a vibration model corresponding to the partial structure on the basis of displacement and reaction force detected in response to shaking and which combines the vibration model and the numerical model with each other to construct a model of the overall system corresponding to the structure and calculates the shaking response of the overall system model.

Abstract: A seismic signal processing method will analyze a resultant set of seismic data, generated in response to a seismic operation performed on a particular portion of an Earth formation, for the purpose of determining a set of geologic characteristics of the particular portion of the Earth formation. When the seismic signal processing method is performed, a cross correlation technique is utilized. In particular, a first data set, which represents a standard set of ‘comparison traces having known geologic characteristics’ and includes two or more traces having known geologic characteristics but does not constitute a part of an input seismic volume, is cross correlated with a second data set having unknown geologic characteristics. As a result of that cross correlation, an output record, known as a ‘correlation spectral volume’, is generated.

Abstract: A seismic prospection method in which a compression seismic wave is emitted into the subsoil and sensors are used to collect seismic data having at least a shear component, and in which the data corresponding to said shear component is processed to deduce information about the geology of the subsoil, the method being characterized in that an estimate of the ratio: ∫ Z 0 Z ⁢ v p ·   ⁢ ⅆ l / ∫ Z 0 Z ⁢ v s ·   ⁢ ⅆ l is determined where vp and vs are values for real loca

Abstract: A method for generating a model of a portion of the floor of a body of water from a plurality of depth measurement sources includes determining an overlap of any of the plurality of depth measurement sources with another depth measurement source and generating a relative shift between any two depth measurement sources that overlap. For each depth measurement source that overlaps with at least one other source, generating an overall shift based on the generated relative shifts. The method also includes generating a desired grid having a plurality of grid nodes and generating a model depth at a plurality of the grid nodes based, at least in part, on a global shift for the measurements of the plurality of sources based on the relative shift. Further, an output is generated of all model depths at respective grid nodes.

Abstract: Method and system intended for seismic monitoring of an underground zone (1), comprising simultaneously using several seismic vibrators. The system comprises for example several local units (LU) comprising each a vibrator (5), a seismic pickup antenna (2), a local acquisition and processing unit (6), and a central control and synchronization unit (8) for simultaneously controlling the various vibrators by means of orthogonal signals, local units (6) being suited, by means of particular; processing, to isolate and to reconstitute the seismograms corresponding to the contributions of the various vibrators. Applications: monitoring of a hydrocarbon reservoir during production or of a reservoir used for gas storage for example.

Abstract: A method of judging the degree of risk of a seismic event by obtaining a condition of activities in the earth's crust using seismic data disclosed in the Internet and the like. An analysis and calculating method capable of calculating sufficiently by way of a personal computer for the purpose of obtaining the conditions of the activities in the earth's crust by means of a dynamical analysis of a continuum more than M5 greater than the value of an empirical rule based on the common analyzing results before a seismic event by analyzing the characteristics of the seismic activities from the value of magnitude and the value of coordinates indicating a seismic source and an occurrence time among seismic data.

Abstract: A model seismic image of a subsurface seismic reflector is constructed, wherein a set of source and receiver pairs is located, and a subsurface velocity function is determined. Specular reflection points are determined on the subsurface seismic reflector for each of the source and receiver pairs. A Fresnel zone is determined on the subsurface seismic reflector for each of the specular reflection points, using the subsurface velocity function. One or more seismic wavelets are selected and a set of image points is defined containing the subsurface seismic reflector. A synthetic seismic amplitude is determined for each of the image points by summing the Fresnel zone synthetic seismic amplitude for all of the Fresnel zones that contain the image point, using the seismic wavelets. The model seismic image of the subsurface seismic reflector is constructed, using the synthetic seismic amplitudes at the image points.

Abstract: A method of analysing seismic survey data in which a transfer function for a geological model is derived by ray tracing techniques applied to theoretical data and the transfer function is applied to actual survey data in order to calculate reflection points (50) and/or other attributes for each shot (42)/receiver (44) pair. The number of ray tracing calculations which have to be performed in deriving the model transfer function can thus be controlled. A sufficiently accurate transfer function can be derived using theoretical data representing substantially fewer shot (42)/receiver (44) pairs than are used in the traditional ray tracing solution applied directly to actual survey data. Attribute values for actual source (42)/receiver (44) pairs are estimated by interpolating the transfer function data.

Abstract: A hybrid approach is disclosed for implementing highly efficient absorbing boundary conditions in three dimensional (3D) finite difference (FD) acoustic applications such as post-stack and pre-stack seismic migration, and forward modeling. The “Perfectly matched layer” (PML) absorbing medium is able to absorb waves arriving at all incidence angle and at any frequency. An optimized PML medium is disclosed including its formulation and implementation to reduce its memory usage and associated computational cost. To avoid costly and cumbersomely implementation of PML medium at the edges and corners of truncated 3D numerical models the PML medium is combined with a “One-way Wave Equation” (1WWE) absorbing boundary to eliminate reflections and diffraction from the edges and corners.

Abstract: A method for obtaining, by means of an inversion process, an optimum model of a physical characteristic in a heterogeneous medium (the impedance of an underground zone in relation to waves transmitted in the ground for example), by taking as the starting point an a priori model of the physical characterized that is optimized by minimizing a cost function dependent on differences between the optimized model which is sought and the known data, considering the a priori model. Construction of the a priori model comprises correlation by kriging between values of the physical quantity known at different points of the medium along discontinuities (strata directions). Uncertainties about the values of the physical quantity in the a priori model in relation to the corresponding values in the medium follow a covariance model that controls the inversion parameters more quantitatively. The characteristics of the covariance model are defined in connection with the structure of the data observed or measured in the medium.

Abstract: Method for gradually deforming, totally or locally, a Gaussian or similar type stochastic model of a heterogeneous medium such as an underground zone, constrained by a series of parameters relative to the structure of the medium. The method comprises drawing a number p, at least equal to two, of independent realizations of at least part of the selected medium model from all the possible realizations, and linear combination of these p realizations with p coefficients such that the sum of their squares is equal to 1. This linear combination constitutes a new realization of the stochastic model and it gradually deforms when the p coefficients are gradually modified. More generally, the method can comprise several iterative gradual deformation stages, with combination at each stage of a composite realization obtained at the previous stage with q new independent realizations drawn from all the realizations.

Abstract: A method, apparatus, and article of manufacture are provided that use measurement data to create a model of a subsurface area. The method includes creating an initial parameterized model having an initial estimate of model parameter uncertainties; considering measurement data from the subsurface area; updating the model and its associated uncertainty estimate; and repeating the considering and updating steps with additional measurement data. A computer-based apparatus and article of manufacture for implementing the method are also disclosed. The method, apparatus, and article of manufacture are particularly useful in assisting oil companies in making hydrocarbon reservoir data acquisition, drilling and field development decisions.

Abstract: A method of obtaining a representative 2D or 3D model of a heterogeneous medium described by multiple physical parameters (such as the impedances of the subsoil in relation to P or S type waves, its density, etc.) from various data. An a priori model with multiple parameters formed from known or estimated isolated values of the physical parameters and the initial model is improved by minimizing a global cost function representative, on the one hand, of the differences between synthetic records giving the response of the current model and the seismic records obtained, and on the other hand of the differences between the current model and the a priori model. These differences are measured in the sense of norms deduced from the a priori information on the uncertainties relative to the data and to the model, and the information can vary from one point of the model to another. The invention has an application for characterization of hydrocarbon reservoirs.

Abstract: A method of seismic surveying and seismic data processing using a plurality of simultaneously recorded seismic energy sources. An activation sequence for each of said plurality of seismic energy sources may be determined such that energy from seismic sources may be recorded simultaneously and seismic energy responsive to individual seismic sources separated into separate source records. The seismic sources are activated using an activation sequence, the recorded seismic energy in the shot recordings may be separated into source recordings responsive to individual seismic sources. The source records may be derived from the shot records using a combination of shot record summations, inversions and filtering.

Abstract: A method of comparing multiple seismic survey data sets of a reservoir, is provided, wherein a first seismic survey data set is taken at a first time and a second seismic survey data set is taken at a second time, to detect changes in the reservoir between the first time and the second time. Generally, the method comprises design of a crossequalization function for the second data set based on a comparison of unchanging portions of the two data sets. Also provided is a processing method for preparing each survey according to similar processing steps with information taken from each survey.

Abstract: Characterizing the value of a particular property, for example, seismic velocity, of a subsurface region of ground is described. In one aspect, the value of the particular property is represented using at least one continuous analytic function such as a Chebychev polynomial. The seismic data may include data derived from at least one crosswell dataset for the subsurface region of interest and may also include other data. In either instance, data may simultaneously be used from a first crosswell dataset in conjunction with one or more other crosswell datasets and/or with the other data. In another aspect, the value of the property is characterized in three dimensions throughout the region of interest using crosswell and/or other data. In still another aspect, crosswell datasets for highly deviated or horizontal boreholes are inherently useful.

Abstract: The invention in a first embodiment comprises a system for generating an estimate of lithological characteristics of a region of the earth's subsurface. A correlation is generated between attributes of synthetic seismic data calculated from log data from at least one wellbore penetrating said region and lithological information from said at least one wellbore. The correlation is then applied to recorded seismic data from the region of the earth's subsurface to generate the estimate.

Abstract: A method for determining measurements of a surface includes determining a trend for a plurality of measurements and determining, for each of at least one of the plurality of measurements, an associated residual between the trend and the measurement and determining, for each of at least one of the associated residuals, an interpolated value for the residual. The method also includes comparing, for each of the at least one associated residuals, the residual to the interpolated value of the residual to determine whether a measurement associated with the residual is anomalous. In response to determining that a measurement associated with the residual is anomalous, the anomalous measurement is discarded. The remaining measurements then represent the surface of interest. The system includes a processor for executing a program of the method. Further, the system includes memory, an input device, and an output device.

Abstract: A method for correcting seismic amplitudes for geometrical artifacts resulting in non-uniform illumination of reflector surfaces. The illumination is calculated for each offset as a function of spatial position. The amplitudes are scaled by a scale factor which may be the reciprocal of the illumination. Data considered to be poor quality due to low illumination may be discarded, and the amplitudes scaled further to compensate for the discarded data.

Abstract: A multi-shooting approach to seismic modeling and acquisition where several shot gathers can be generated simultaneously. The method is called a multi-shooting approach to seismic modeling and acquisition. A multi-shooting modeling method is disclosed which may be carried out on a computer system in either an explicit or an implicit manner. A multi-shooting acquisition method is also disclosed. The finite difference technique has the ability to generate elastic waves from several locations and at different time intervals simultaneously. The multi-shooting approach is based on the property of the finite difference technique. The decoding solution exploits the fact that specific time delays can be imposed between the various shots and that two closely space shooting points produce nearly identical responses.

Abstract: A method for calculating seismic velocity for migration purposes as a function of subsurface spatial position that gives the seismic processing analyst direct control of the resulting migration velocity model, and includes a means to ensure that the model is consistent with RMS velocity sweeps computed from available surface seismic or other data. The method involves generating average velocities from the model to compare to the measured RMS velocity data, and comparing the model predictions to actual data on a 3-D interactive visual display allowing quick and easy model adjustment. Other available measured data besides surface seismic data maybe used to develop the model.

Abstract: Volume Seismic textures are evaluated using a Voxel Coupling Matrix (VCM) to capture and characterize three dimensional seismic reflection patterns. To extract the VCM seismic textural information at a specific location within the seismic amplitude input data, a finite number of neighboring voxels called a texture element (texel) are processed to create the VCM. The VCM is then processed to create a plurality of texture attributes. This processing is performed at each voxel location throughout the whole seismic data volume to create multiple texture attribute volumes. These attribute volumes are subsequently used as inputs into an attribute-trace classification method to produce a seismic interpretation volume. The interpretation volume is displayed using any number of distinct colors to represent various numbers of classes of reflection patterns present within the seismic volume.