Amplitude Patents (Class 367/47)
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Publication number: 20090052279Abstract: A method and system determines optimum azimuth parameters for seismic data processing. The method includes selecting a range of azimuth parameters, the azimuth parameters indicating the range of magnitudes and directions, each pair of azimuth parameters indicating a particular magnitude and a particular direction. The method further includes generating a plurality of seismic gathers wherein a seismic gather is generated from each pair of azimuth parameters, each seismic gather including a plurality of seismic data traces. The method further includes generating a plurality of seismic gathers for a plurality of imaging locations and a plurality of depths, each seismic gather containing a plurality of seismic data traces. The method further includes determining the coherence amplitude of each gather. The method further includes determining the gather having the optimum coherence amplitude, and selecting the azimuth parameters associated with the gather having the optimum coherence amplitude.Type: ApplicationFiled: August 21, 2007Publication date: February 26, 2009Inventors: Charles Sicking, E. Stuart Nelan, William H. McLain
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DYNAMICALLY ALLOCATING DIFFERENT NUMBERS OF BITS TO WINDOWS OF A SERIES REPRESENTING A SEISMIC TRACE
Publication number: 20090034367Abstract: To process seismic data, a set of data values representing a seismic trace is received, and amplitudes of data values associated with plural groups in the set are analyzed. Different numbers of bits are dynamically allocated to at least some of the groups of the set according to the analyzing.Type: ApplicationFiled: July 11, 2008Publication date: February 5, 2009Inventor: Francis G. Sherrill -
Publication number: 20090028000Abstract: A method for the identification of metallic deposits in a rock formation is provided. The method for the identification includes the steps of providing an acoustic source for generating frequencies to produce acoustic waves, arranging at least one geophone optimized to detect the frequencies and oriented to enhance reflection planes from faults and fractures associated with an ore body in a rock formation and locating the acoustic source and at least one geophone in at least one shallow bore hole beneath unconsolidated surface material of the rock formation. The method further includes the steps of directing the acoustic waves to an underlying rock formation to generate seismic reflection data and processing the seismic reflection data by altering the frequency and the amplitude to identify unique seismic attributes that allow detection of at least one metallic deposit or ore body in the rock formation.Type: ApplicationFiled: July 25, 2008Publication date: January 29, 2009Inventor: Thomas B. O'Brien
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Publication number: 20090010104Abstract: Methods and systems for processing microseismic waveforms. The methods and systems provide determining a measure of waveform fit in the frequency-domain comprising constructing, in the frequency-domain, at least one of an amplitude misfit functional and a cross phase functional between arrivals; and estimating source parameters and/or model parameters.Type: ApplicationFiled: July 4, 2008Publication date: January 8, 2009Applicant: SCHLUMBERGER TECHNOLOGY CORPORATIONInventor: W. Scott LEANEY
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Publication number: 20090003131Abstract: A method and apparatus control a plurality of sonic sources to generate sound waves within at least one opening of an item. The “item” can comprise almost anything that has a percolation path (a path where solid particles are to be separated from liquid particles), such as the ground, aggregates, porous structures, porous materials, and a semi-solid structure. By controlling the sonic sources, the method transmits the sound waves to the percolation path. Further, the method regulates the amplitude and frequency of the sound waves such that the liquid particles oscillate out of phase with the solid particles. The method also regulates the phases of the sound waves generated by the different sonic sources so as to control locations within the percolation path where the liquid particles oscillate out of phase with the solid particles.Type: ApplicationFiled: June 28, 2007Publication date: January 1, 2009Inventor: Robert Jay Meyer
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Patent number: 7453764Abstract: A method of imaging in an underground formation one or more steep-sloping geologic interfaces, which are not necessarily in a plane, by forming with primary reflectors, which are not necessarily in a plane, dihedra giving rise to prismatic seismic reflections (double reflections). The geometry of the steep-sloping interface is determined from choosing seismic records of one or more events corresponding to prismatic reflections for different source-pickup pairs of an acquisition device. A new reflection tomography technique is used, wherein introduction of specific constraints guarantees the convergence of the algorithm. The velocity distribution in the geologic formation and/or the geometry of the interface(s) between the sedimentary layers can be known otherwise or determined by means of the method. The method can apply to a formation comprising several different sloping interfaces.Type: GrantFiled: March 23, 2005Date of Patent: November 18, 2008Assignee: Institut Farncais du PetroleInventors: Maud Cavalca, Patrick Lailly
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Patent number: 7366054Abstract: 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 Radon transformation. A corrective filter is then applied to enhance the primary reflection signal content of the data and to eliminate unwanted noise events. The corrective filter has a pass region with a lower pass limit and a higher pass limit. The higher pass limit is set within 15% above the slowness of the primary reflection signals and, preferably, it is more closely set to the slowness of the primary reflection signals. The lower pass limit is also preferably set within 15% below the slowness of the primary reflection signals.Type: GrantFiled: December 29, 2006Date of Patent: April 29, 2008Inventor: Lawrence C. Wood
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Patent number: 7343245Abstract: A method of seismic analysis is disclosed for extracting information relating to lithology, porosity, fluids, and AVO types and/or displaying the extracted information. In one possible embodiment, AVO points are plotted and a distance and/or angle is utilized for extracting this information. Various portrayals of the extracted information displays may be produced including displays wherein the extracted information is then displayed in terms of colors for respective x, y, z locations. The AVO points may or may not be normalized based on a shape of a cluster of the AVO points prior to extraction of the information.Type: GrantFiled: June 9, 2005Date of Patent: March 11, 2008Assignee: eSeis, Inc.Inventors: Roger A. Young, Robert D. LoPiccolo
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Patent number: 7333393Abstract: A new approach is described based on reciprocity for estimating acquisition-related effects, which has several advantages over conventional surface-consistent processing techniques: (i) It can be applied to complete recordings, hence does not require the isolation of primary reflections in the data, (ii) no assumptions are imposed on the subsurface, and (iii) it is applicable to multi-component data. The application of reciprocity requires symmetric data acquisition, i.e. identical source and receiver patterns, identical locations, and the source orientations have to be identical to the receiver components. Besides reciprocity, additional constraints are required to determine the lateral source and receiver amplitude variations fully. Criteria based on minimizing total energy differences between adjacent common source and common receiver gathers, and in common offset panels of the medium response are applied.Type: GrantFiled: November 28, 2005Date of Patent: February 19, 2008Assignee: Westerngeco L.L.C.Inventors: Robbert Van Vossen, Andrew Curtis, Jeannot Trampert
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Patent number: 7283422Abstract: Methods for determining the existence and characteristics of a gradational pressurized zone within a subterranean formation are disclosed. One embodiment involves employing an attenuation relationship between a seismic response signal and increasing wavelet wavelength, which relationship may be used to detect a gradational pressurized zone and/or determine characteristics thereof. In another embodiment, a method for analyzing data contained within a response signal for signal characteristics that may change in relation to the distance between an input signal source and the gradational pressurized zone is disclosed. In a further embodiment, the relationship between response signal wavelet frequency and comparative amplitude may be used to estimate an optimal wavelet wavelength or range of wavelengths used for data processing or input signal selection. Systems for seismic exploration and data analysis for practicing the above-mentioned method embodiments are also disclosed.Type: GrantFiled: May 24, 2006Date of Patent: October 16, 2007Assignee: Battelle Energy Alliance, LLCInventors: G. Michael Shook, Samuel D. LeRoy, William M. Benzing
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Patent number: 7239578Abstract: 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 Radon transformation. At least of subset of the transformed data is filtered to enhance its coherent noise content and to diminish its primary reflection signal content by defining a slowness high-pass region and, a slowness low-pass region. The low-pass region is defined to enhance the low slowness coherent noise content and to diminish the primary reflection signal content thereof, thereby generating a first subset of said transformed data having enhanced low slowness coherent noise content.Type: GrantFiled: March 3, 2005Date of Patent: July 3, 2007Inventor: John M. Robinson
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Patent number: 7230879Abstract: The present invention provides a method and apparatus for arriving at true relative amplitude destretched seismic traces from stretched seismic traces. The method compensates for offset varying reflection interference effects due to normal moveout. Stretch factors ? and also input spectra are determined for NMOR stretched seismic traces. Estimates are then made of stretched wavelet spectra from the input spectra. A destretched wavelet spectra is then obtained. Shaping correction factors are determined by taking the ratio of the destretched wavelet spectra to the stretched wavelet spectra and are applied to the input spectra of the stretched traces to arrive at a destretched trace spectra. True relative amplitude scaling factors are computed by taking the ratio of a true relative amplitude property of the destretched wavelet spectra to a corresponding true relative amplitude property of the stretched wavelet spectra.Type: GrantFiled: February 12, 2005Date of Patent: June 12, 2007Assignee: Chevron U.S.A. Inc.Inventors: E. Frederic Herkenhoff, Richard B. Alford, Harry L. Martin
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Patent number: 7167414Abstract: A method is disclosed for amplitude preserving Kirchhoff time migration. The method includes calculating estimates of the geometrical spreading terms using a constant velocity approximation. Takeoff and emergence angles are accurately calculated based on a model of velocity which varies with respect to travel time. An image can be calculated at at least one travel time using the estimated weights and calculated takeoff and emergence angles.Type: GrantFiled: October 4, 2004Date of Patent: January 23, 2007Assignee: PGS Americas, Inc.Inventors: Seongbok Lee, David Graham King
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Patent number: 7110323Abstract: A Method for Interpreting Seismic Data Using Duplex Waves is described. Whereas substantially horizontal boundaries are readily identified using conventional processing methods based on primary reflections, it has been difficult or impossible to use such methods for locating substantially vertical events or boundaries. The method of the present invention uses secondary reflections to locate substantially vertical events by gathering common source or receiver traces for processing. Wave fields of these gathers are continued downward to the level of the base boundary, then at each discrete depth level, a seismic image of sub-vertical events is formed. The downward-continued gathers correspond to the travel time of the wave from when it left the source or the receiver point, was reflected from the base boundary, and arrived to the corresponding point of the discrete level of wave-field continuation.Type: GrantFiled: August 18, 2004Date of Patent: September 19, 2006Inventors: Naum Marmalyevskyy, Zynoviy V. Gornyak, Alexander S. Kostyukevych, Viktor V. Mershchiy, Yuriy V. Roganov
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Patent number: 7095677Abstract: A method of seismic data analysis to provide clustering of A.V.O. data into A.V.O. anomaly types, the method comprising: obtaining successive values of a plurality of seismic attributes, each seismic attribute comprising a respective property of a seismic reflection event, grouping said values using a running window of a predetermined size into a plurality of groups, for each group identifying first and second parameters corresponding to said first and second attributes, and plotting each group as a single event based on said group parameters, said group parameters having been selected to cause clustering of said seismic reflection events on said plot according to the presence or absence of A.V.O. anomalies.Type: GrantFiled: May 27, 2003Date of Patent: August 22, 2006Assignee: Paradigm GeophysicalInventor: Anat Canning
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Patent number: 7079449Abstract: Methods for determining the existence and characteristics of a gradational pressurized zone within a subterranean formation are disclosed. One embodiment involves employing an attenuation relationship between a seismic response signal and increasing wavelet wavelength, which relationship may be used to detect a gradational pressurized zone and/or determine characteristics thereof. In another embodiment, a method for analyzing data contained within a response signal for signal characteristics that may change in relation to the distance between an input signal source and the gradational pressurized zone is disclosed. In a further embodiment, the relationship between response signal wavelet frequency and comparative amplitude may be used to estimate an optimal wavelet wavelength or range of wavelengths used for data processing or input signal selection. Systems for seismic exploration and data analysis for practicing the above-mentioned method embodiments are also disclosed.Type: GrantFiled: February 18, 2003Date of Patent: July 18, 2006Assignee: Batelle Energy Alliance, LLCInventors: G. Michael Shook, Samuel D. LeRoy, William M. Benzing
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Patent number: 6987706Abstract: Methods of processing seismic data to remove unwanted noise from meaningful reflection signals are provided for. The seismic data is transformed from the offset-time domain to the time-slowness domain using a high resolution Radon transformation. That is, the Radon transformation is performed 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. A corrective filter is then applied to 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.Type: GrantFiled: September 10, 2002Date of Patent: January 17, 2006Inventor: Lawrence C. Wood
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Patent number: 6985404Abstract: 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.Type: GrantFiled: June 4, 2003Date of Patent: January 10, 2006Assignee: WesternGeco, L.L.C.Inventor: Subhashis Mallick
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Patent number: 6950371Abstract: 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.Type: GrantFiled: May 20, 2003Date of Patent: September 27, 2005Assignee: Chevron U.S.A. Inc.Inventors: E. Fredrick Herkenhoff, Dennis G. Bones, Kendall Bong Hu Louie
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Publication number: 20040246817Abstract: 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.Type: ApplicationFiled: June 4, 2003Publication date: December 9, 2004Inventor: Subhashis Mallick
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Publication number: 20040240321Abstract: A method of seismic data analysis to provide clustering of A.V.O. data into A.V.O. anomaly types, the method comprising: obtaining successive values of a plurality of seismic attributes, each seismic attribute comprising a respective property of a seismic reflection event, grouping said values using a running window of a predetermined size into a plurality of groups, for each group identifying first and second parameters corresponding to said first and second attributes, and plotting each group as a single event based on said group parameters, said group parameters having been selected to cause clustering of said seismic reflection events on said plot according to the presence or absence of A.V.O. anomalies.Type: ApplicationFiled: May 27, 2003Publication date: December 2, 2004Applicant: Paradigm Geophysical (Luxembourg) s.a.r.l.Inventor: Anat Canning
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Publication number: 20040233782Abstract: 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.Type: ApplicationFiled: May 20, 2003Publication date: November 25, 2004Applicant: Chevron U.S.A. Inc.Inventors: E. Fredrick Herkenhoff, Dennis G. Bones, Kendall Bong Hu Louie
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Patent number: 6801473Abstract: 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.Type: GrantFiled: March 12, 2003Date of Patent: October 5, 2004Assignee: ExxonMobil Upstream Research CompanyInventors: Gianni Matteucci, Yuan Wang, Linda J. Zimmerman
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Patent number: 6757216Abstract: A method for assessing the suitability of seismic data for quantitative amplitude analysis, where the concern is excessive residual normal moveout (RNMO). The invention uses a near offset stack and a far offset stack, the time difference between the two, a mute pattern, a reflection shape assumption for the RNMO, and a waveform and frequency for the far stack traces to generate a formula that estimates far stack amplitude error caused by RNMO. The formula can be used to compensate the far stack amplitude where the error is not so great as to require reprocessing of the data. The method can also be applied to interpreted amplitude maps.Type: GrantFiled: May 15, 2003Date of Patent: June 29, 2004Assignee: ExxonMobil Upstream Research CompanyInventors: Peter Varnai, Stefan Hussenoeder, Brian P. West, John E. Eastwood, Spyridon K. Lazaratos
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Patent number: 6343256Abstract: 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.Type: GrantFiled: June 12, 2000Date of Patent: January 29, 2002Assignee: ExxonMobil Upstream Research CompanyInventors: Graham A. Winbow, James R. Alldridge, Leslie A. Wahrmund
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Patent number: 6317384Abstract: A method for identifying faults and stratigraphic features within seismic data without interpreter bias by processing seismic data to identify the minimum difference between seismic traces. Large values of difference are plotted as display attributes for seismic reflection data interpretation for two-dimensional and three-dimensional seismic data. The large values of difference represent faults and stratigraphic features within the seismic data. Dip azimuth and dip magnitude attributes can be generated and displayed as well.Type: GrantFiled: November 15, 1999Date of Patent: November 13, 2001Assignee: Chevron U.S.A., Inc.Inventors: Yi Luo, William G. Higgs
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Patent number: 6278950Abstract: A method for compensating for amplitude loss in a set of seismic traces, where the amplitude loss is caused by shallow attenuation anomalies. Attenuation factors are calculated from first-arrival amplitudes for long-offset seismic data traces. Those factors are calculated by numerical methods, using matrix inversion and iteration. Those factors are used to adjust upward the amplitudes of all later-arriving seismic traces. Frequency dependent attenuation is treated by dividing the seismic traces into frequency ranges using band-pass filters, then using the above-described method within each frequency range after which the adjusted amplitudes are recombined. Amplitude variations caused by inconsistencies in the data acquisition system, such as a source strength variation, are also treated by a similar approach.Type: GrantFiled: March 2, 2000Date of Patent: August 21, 2001Assignee: ExxonMobil Upstream Research Co.Inventors: Young C. Kim, Arturo E. Romero, Jr., Michael M. Deal
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Patent number: 6058074Abstract: A computer system and method of operating the same to apply overburden corrections to seismic signals prior to amplitude-versus-offset (AVO) analysis is disclosed. The system and method retrieve common midpoint gathers of the seismic signals, and generate analytical, or complex, AVO intercept and AVO slope traces therefrom, effectively stacking the traces in each gather. Over a sliding time window of the stacks, the computer system generates p-measure standard deviation and correlation statistics, preferably using a p-measure value less than one. The AVO intercept and AVO slope traces are then modified, at each depth point of interest corresponding to a time window placement, according to the relationship between the p-measure statistics and the desired statistics for the background distribution.Type: GrantFiled: July 31, 1998Date of Patent: May 2, 2000Assignee: Atlantic Richfield CompanyInventors: Herbert W. Swan, Bruce J. Verwest
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Patent number: 6041017Abstract: A method of producing images of the limits of a geologic reservoir from measurements of fluid pressure in a well controlled to produce from the reservoir at a constant flow rate. The measurements are taken over a period of time, which includes initiation of well flow and recorded in a plot of well pressure v. time. The method includes detecting abrupt changes in slope of the pressure v. time function, where each abrupt change signifies the arrival of a primary shock wave at a discrete section of a boundary limit of the reservoir; and calculating the minimum radial distance to the discrete section from the well bore as a function of wave travel time. The changes in the slope of the pressure v. time function are used to calculate the curvature of the boundary at the minimum radial distance.Type: GrantFiled: August 5, 1997Date of Patent: March 21, 2000Assignee: Fred L. GoldsberryInventor: Fred L. Goldsberry
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Patent number: 6028820Abstract: A method for seismic data interpretation for the purposes of identification of oil, gas and water accumulation locations and delineation of their contours uses a model of discrete media with inhomogeneous stresses. For a selected reflection horizon, the relative value of overall pressure gradient is calculated on the basis of instantaneous amplitudes and frequencies of seismic signals using a derived relationship between the reflection coefficients of elastic waves and the stress condition parameter. The calculation technique uses estimates of instantaneous amplitudes and frequencies smoothed over the entire seismic horizon or its fragment. A generalized model of normal (lithostatic) pressure is excluded, and the final interpreted parameters have the sense of relative estimates of anomalous pressure caused by basin dynamics.Type: GrantFiled: August 14, 1998Date of Patent: February 22, 2000Assignee: Trans Seismic International, Inc.Inventor: Vladimir B. Pisetski
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Patent number: 6026057Abstract: A method and computer system for correcting seismic signals in a seismic survey, sensed in horizontal and vertical directions at receiver locations, is disclosed. According to the disclosed method and system, the horizontal and vertical seismic signal traces are processed in prestack gathers, after normal move-out correction. For each reflection event indicated in the prestack gathers, a performance function is evaluated over a range of zero-offset directivity and directivity slope values, using the horizontal and vertical pressure wave components sensed at the receivers. The zero-offset directivity and directivity slope values that return the maximum performance function are stored in connection with the gather and the reflection event, as indicative of the zero-offset dip and offset-dependent directivity of the reflective surface corresponding to the reflected event.Type: GrantFiled: June 4, 1998Date of Patent: February 15, 2000Assignee: Atlantic Richfield CompanyInventors: Bok S. Byun, E. Stuart Nelan, Chi Young
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Patent number: 6014342Abstract: A method of evaluating a subsurface region by separating/enhancing a certain type of seismic event data of interest from an overall set of seismic event data which includes other, different types of seismic event data is disclosed herein. In accordance with one feature, a particular type of gather is generated from the seismic event data such that the gather includes at least a portion of the data which is of interest and at least a portion of the other data. A series of data discrimination lines are incorporated into the gather at positions and directions which are established in the gather in a predetermined way. Using the data discrimination lines, the data of interest which is present in the gather is separated/enhanced with respect to the other data within the gather. The separated data may be used for example in producing a map of the particular subterranean region.Type: GrantFiled: July 16, 1997Date of Patent: January 11, 2000Assignee: Tomo Seis, Inc.Inventor: Spyridon K. Lazaratos
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Patent number: 5986974Abstract: A method for identifying faults and stratigraphic features within seismic data without interpreter bias by processing seismic data to identify the minimum difference between seismic traces. Large values of difference are plotted as display attributes for seismic reflection data interpretation for two-dimensional and three-dimensional seismic data. The large values of difference represent faults and stratigraphic features within the seismic data. Dip azimuth and dip magnitude attributes can be generated and displayed as well.Type: GrantFiled: February 27, 1998Date of Patent: November 16, 1999Assignee: Chevron U.S.A., Inc.Inventors: Yi Luo, William G. Higgs
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Patent number: 5978314Abstract: A method for determining a substantially optimal NMO velocity function for use in stacking a CMP gather of seismic data traces. The method begins with an initial estimate of the NMO velocity function for the CMP gather. This initial estimate is typically determined through conventional seismic velocity analysis. The method then picks a first velocity-traveltime pair falling on the initial estimate of the NMO velocity function and conducts a two-dimensional interpolative search of trial velocity-traveltime pairs in the neighborhood of the pick to find a substantially optimal velocity-traveltime pair. This substantially optimal velocity-traveltime pair is the trial velocity-traveltime pair having the highest stack response and is substituted for the pick in the NMO velocity function. The method then proceeds to find substantially optimal velocity-traveltime pairs to replace each of the other picks on the initial estimate of the NMO velocity function.Type: GrantFiled: March 21, 1997Date of Patent: November 2, 1999Assignee: Exxon Production Research CompanyInventor: Long Don Pham
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Patent number: 5946271Abstract: A discrete, minimally-equipped standard seismic calibration system is permanently installed over a subsurface reservoir structure that contains fluids of economic interest. Changes in the fluid content as a function of long-term time lapse may introduce changes in the acoustical characteristics of the reservoir rock layers, producing a corresponding change in the seismic signature recorded by the calibration system. The difference between two signatures over a selected time epoch defines a time-lapse calibration signature. The time lapse calibration signature can be applied to reduce the results of different conventional seismic data-acquisition systems of different vintages and technologies to a common standard.Type: GrantFiled: March 21, 1997Date of Patent: August 31, 1999Assignee: Western Atlas International, Inc.Inventor: William Henry Dragoset, Jr.
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Patent number: 5862100Abstract: A method and system for producing an indicator for amplitude-versus-offset (AVO) analysis of seismic survey data is disclosed. According to the disclosed method and system, a raw AVO indicator is generated for each of multiple depth points, from the AVO intercept and gradient coefficient values. The indicator is generally a positive amplitude number for those locations having petrophysical importance, while the background neighboring points will have a zero or negative value for the raw indicator. Statistics are derived for a group of depth points that surround the depth point under analysis, in time and in space, from which a probability function may be evaluated, assuming a distribution of values in the background trend of AVO intercept and gradient values, and based upon which the raw AVO indicator will be modified. In one embodiment, the probability function is evaluated to determine the loci of points that are within the background to a certain statistical confidence.Type: GrantFiled: May 28, 1996Date of Patent: January 19, 1999Assignee: Atlantic Richfield CompanyInventor: Bruce J. VerWest
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Patent number: 5831935Abstract: A method for identifying faults and stratigraphic features within seismic data without interpreter bias by processing seismic data to identify the minimum difference between seismic traces. Large values of difference are plotted as display attributes for seismic reflection data interpretation for two-dimensional and three-dimensional seismic data. The large values of difference represent faults and stratigraphic features within the seismic data. Dip azimuth and dip magnitude attributes can be generated and displayed as well.Type: GrantFiled: March 5, 1996Date of Patent: November 3, 1998Assignee: Chevron U.S.A. Inc.Inventors: Yi Luo, William G. Higgs
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Patent number: 5825716Abstract: A method for eliminating the influence of multiple reflections in seismic data by determining an up going and down going vector wave-field from the vector wave-field, determining a product of the free surface refection coefficient and the down going vector wave-field, and adding the product to the up going vector wave-field. Also provided is a method for eliminating the effects of receiver coupling from seismic data taken in a survey by describing a first cross-equalization filter as a function of the reverberation period, describing a second cross equalization filter as a function of the seismic data, deriving an inverse coupling filter as a function of the first cross-equalization filter and the second-equalization filter, and applying the coupling filter to the seismic data.Type: GrantFiled: May 7, 1997Date of Patent: October 20, 1998Assignee: PGS Tensor Inc.Inventor: Joel G. Starr
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Patent number: 5818795Abstract: A method of suppression of burst coherent noise in seismic data is provided comprising (a) comparing a threshold amplitude characteristic acceptance value for a time window of a reference trace to an amplitude characteristic of a test trace of a set of traces within the window and; (b) applying a non-zero scalar to the test trace in the time window if an amplitude of the test trace within the time window is not within the threshold amplitude characteristic acceptance value.Type: GrantFiled: October 30, 1996Date of Patent: October 6, 1998Assignee: PGS Tensor, Inc.Inventors: Keith Hawkins, Simon Rice Barnes, Gregory Peter Gwyn Fookes
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Patent number: 5784334Abstract: A computer-operated method for analyzing seismic data to discern the presence of hydrocarbon-bearing formations is disclosed. According to the disclosed method and system, amplitude-versus-offset (AVO) analysis is performed to assign, for each depth point in a survey region, an AVO intercept value and an AVO gradient value; the AVO intercept value corresponds to the zero-offset response for acoustic reflections from the depth point, while the AVO gradient value corresponds to the rate of change of the amplitude as a function of the angle of incidence of the acoustic energy (typically, with the square of the sine of the angle).Type: GrantFiled: March 13, 1996Date of Patent: July 21, 1998Assignee: Atlantic Richfield CompanyInventors: Arcangelo G. Sena, Herbert W. Swan
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Patent number: 5781502Abstract: The present invention relates to a filtering method for discriminating elliptical waves among other waves propagating in a material medium (such as a geologic formation for example) by a combined processing of the components measured along several axes of the waves received by a multi-axis receiver. It comprises detection by at least one receiver (R) (consisting for example of one or several directional detectors such as geophones or accelerometers coupled with said formation) of the wave components in at least two orthogonal directions. A determination (by a processing assembly (1)) of the wavelet transforms of the signals is produced by this receiver (R) in response to the waves received and selection of the amplitudes of the signals resulting from this wavelet transformation is performed according to a criterion based on the ratio of the respective amplitudes thereof. The method can be used for the filtering of surface or tube waves within the scope of a seismic exploration.Type: GrantFiled: July 24, 1996Date of Patent: July 14, 1998Assignee: Institut Francais du PetroleInventor: Marc Becquey
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Patent number: 5661697Abstract: A method and apparatus for analyzing amplitude-versus-offset (AVO) seismic data to distinguish sand formations, such as Morrow sands, from limestones and other similar intervals, is disclosed. For each of the traces in the survey, AVO intercept and AVO slope traces are generated, preferably after normalization of the amplitudes of the traces to account for geophone coupling variations. After normalization and conventional processing and corrections, spatial summation may be performed to further improve the traces. AVO trend lines are then generated, preferably on a weighted window basis, to generate localized trend lines against which the intercept and slope values of individual depth points may be compared. This comparison allows the plotting of AVO intercept versus AVO slope deviation from the trend line, from which sand formation interfaces may be identified by their presence in certain quadrants of the intercept-slope deviation cross-plot.Type: GrantFiled: December 18, 1995Date of Patent: August 26, 1997Assignee: Atlantic Richfield CompanyInventors: Herbert W. Swan, Kenneth O. McDowell, James A. Specht
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Patent number: 5642327Abstract: Disclosed is a method for creating a gain function for seismic data and to processing methods for utilizing such a gain function. The method of creating the gain function generally includes representing the seismic data as a plot of the logarithm of amplitude versus time. Various order polynomial functions are subsequently fitted to the plotted seismic data. The best fitting polynomial is then selected from these various order polynomials, the inverse of which is the gain function. This gain function can be utilized in a seismic processing method.Type: GrantFiled: June 8, 1994Date of Patent: June 24, 1997Assignee: Exxon Production Research CompanyInventors: Larry J. Schiflett, Michael P. Thornton
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Patent number: 5596546Abstract: A method of preserving frequency components in digitally sampled signals exceeding a maximum frequency related to a predetermined digital sample interval. The signals correspond to a plurality of sensors positioned at spaced apart locations, and the signals from each of the plurality of sensors are digitally sampled at the predetermined digital sample interval. The method includes the steps of determining time adjustment values corresponding to each sensor which provide amplitude correspondence between each of the signals generated by each of the sensors in response to different propagation times of energy from an energy source to each of the sensors; adjusting a time of acquisition of each digital sample from each of the sensors by applying the corresponding time adjustment value to generate time-adjusted samples; and combining all the time adjusted samples into a combined output signal having a sampling time interval smaller than the predetermined digital sample interval.Type: GrantFiled: December 21, 1994Date of Patent: January 21, 1997Assignee: Western Atlas International, Inc.Inventor: R. Daniel Wisecup
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Patent number: 5555218Abstract: The amplitude spectrum is generated within a selected time window of a seismic time scale recording. The rate of change, Q, of the natural logarithm of the signal amplitude is measured with respect to frequency. A Q-derived static time shift is computed and applied to the selected seismic time scale trace to correct the raw seismic times for dispersion-induced time distortion. Amplitude-correction and phase-correction filters are applied to the static-corrected trace to provide a new time scale trace corrected for velocity dispersion which is processed to provide a physical model of the subsurface of the earth.Type: GrantFiled: February 27, 1995Date of Patent: September 10, 1996Assignee: Western Atlas International, Inc.Inventors: Ronald E. Chambers, Subhashis Mallick
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Patent number: 5515335Abstract: A method for generating improved displays of seismic data by processing seismic amplitude versus offset data to correct for overburden effects. Analytic traces are calculated for the zero offset reflectivity, A, trace and the amplitude versus offset slope, B, trace of the AVO data. Statistics for the A and B traces within a selected window in time and common depth point space about a selected sample point are calculated. The statistics include root mean square amplitudes of the A and B traces and the correlation coefficient. Desired statistics are selected and used with the measured statistics to correct the A and B traces.Type: GrantFiled: August 16, 1993Date of Patent: May 7, 1996Assignee: Atlantic Richfield CompanyInventor: Herbert W. Swan
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Patent number: 5487001Abstract: A method is provided for determining petrophysical properties associated with various lateral locations of a subterranean layer. The method employs velocity and density log data, corresponding to a preselected reference lateral location, in combination with seismic data to determine a range of values of at least one petrophysical property associated with a desired lateral location ("nonreference") offset from the reference lateral location.Type: GrantFiled: May 28, 1993Date of Patent: January 23, 1996Inventor: Dennis B. Neff
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Patent number: 5479376Abstract: The relative amplitudes of seismic reflection data contains very useful information about the subsurface earth formations. Surface and subsurface-consistent amplitude processing identifies and corrects for the variability introduced by instrumentation and surface distortions. Dynamic amplitude decomposition, the subject of this disclosure, identifies and compensates for reflection amplitude fading due to subsurface transmission absorption media.Type: GrantFiled: August 30, 1993Date of Patent: December 26, 1995Assignee: Western Atlas International, Inc.Inventors: Alfonso Gonzalez, Ronald E. Chambers
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Patent number: 5453958Abstract: A method is provided by which the presence, if any, and location of a hydrocarbon reservoir or reservoirs adjacent to a subterranean surface can be determined based on DAD values which correspond to grid points of the surface. DAD values, specifically defined herein, relate to the change in seismic amplitude (Delta Amplitude) as divided by the Dip magnitude at each grid point. According to a preferred embodiment, colors are assigned to grid points based on the sign of the DAD values, and such assigned colors are plotted onto a depth/time contour map of the subterranean surface to result in a display which clearly indicates the location of any hydrocarbons.Type: GrantFiled: June 11, 1993Date of Patent: September 26, 1995Assignee: Phillips Petroleum CompanyInventor: Dennis B. Neff
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Patent number: 5440525Abstract: A method for displaying seismic data to provide direct indications of the presence of hydrocarbons. Seismic data is processed using conventional amplitude versus offset techniques to obtain zero offset reflectivity, or A, traces and the amplitude versus offset slope, or B, traces. AB cross plots of each trace are then generated. Each sample point on the cross plot is then assigned a value corresponding to its deviation from the regression line of the cross plotted AB points. The assigned values are then plotted in their corresponding time sample positions to generate a trace or display providing a direct indication of hydrocarbons.Type: GrantFiled: October 25, 1993Date of Patent: August 8, 1995Assignee: Atlantic Richfield CompanyInventors: Samir K. Dey-Sarkar, Douglas J. Foster, Steven W. Smith, Herbert W. Swan