United States Patent [19]
`Starr
`
`[54] METHOD OF CREATING COMMON-
`OFFSET/COMMON-AZIMUTH GATHERS IN
`3-D SEISMIC SURVEYS AND METHOD OF
`CONDUCTING REFLECTION ATTRIBUTE
`VARIATION ANALYSIS
`
`Inventor: Joel Starr, Richmond, TeX.
`
`Assignee: Petroleum Geo-Services (US), Inc.,
`Houston, TeX.
`
`Appl. No.: 08/970,674
`Filed:
`Nov. 14, 1997
`
`Int. Cl.7 ..................................................... .. G01V 1/04
`US. Cl. ................................ .. 367/72; 367/56; 367/58
`Field of Search ................................ .. 367/52, 53, 72,
`367/56, 58, 38, 59
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,241,429 12/1980 Bloomquist et al. ................... .. 367/52
`4,742,497
`5/1988 Beasley et al. .... ..
`.. 367/53
`4,797,861
`1/1989 Beasley .......... ..
`.. 367/72
`4,980,866 12/1990 Wang et al. ............................ .. 367/52
`5,402,391
`3/1995 Cordsen.
`
`US006026059A
`[11] Patent Number:
`[45] Date of Patent:
`
`6,026,059
`Feb. 15, 2000
`
`FOREIGN PATENT DOCUMENTS
`726307 In 966 Canada‘
`
`Primary Examiner—Christine K. Oda
`Assistant Examiner—Anthony Jolly
`Attorney, Agent, or Firm—Arnold & Associates
`[57]
`ABSTRACT
`
`Processes are described for providing a data set useful for
`performing analysis of re?ection attribute variation among
`traces in a Window of three-dimensional seismic data,
`Wherein the traces have a re?ection point assigned thereto
`and Wherein the traces represent recordings from shot
`receiver pairs having various azimuth angles. According to
`one embodiment, the process comprises: assigning an offset
`value to a plurality of traces; ?tting a substantially conical
`surface having a major and a minor axis to the data of the
`traces Within the Window, Wherein: the major aXis of the
`cone represents the azimuth direction having the loWest
`variation in the re?ection attribute, and the minor axis of the
`cone represents the azimuth direction having the highest
`variation in the re?ection attribute; assigning a coordinate
`set to the surface, Wherein the coordinate set is related to a
`survey geometry of the data; and comparing the re?ection
`attribute variation as a function of offset and azimuth.
`
`43 Claims, 8 Drawing Sheets
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`Quadrant II
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`Quadrant lll
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`Quadrant IV
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`08Zl 09SZ
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`WesternGeco Ex. 1001, pg. 1
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`

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`U.S. Patent
`
`Feb. 15,2000
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`Sheet 1 0f8
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`6,026,059
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`WesternGeco Ex. 1001, pg. 2
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 2 0f8
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`6,026,059
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`WesternGeco Ex. 1001, pg. 3
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 3 0f8
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`6,026,059
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`FIG. 3
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`WesternGeco Ex. 1001, pg. 4
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 4 0f8
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`6,026,059
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`878 1756 2634 3512 4390 S268 6147 7025
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`0B1 0B2 0B3 0B4 085
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`0
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`878 1756 2634 3512 430 52768 ‘6147 7025
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`FIG. 4
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`WesternGeco Ex. 1001, pg. 5
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 5 0f8
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`6,026,059
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`FIG. 5
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`WesternGeco Ex. 1001, pg. 6
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 6 0f 8
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`6,026,059
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`6400
`4800
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`1600
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`4600
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`4800
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`-6400
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`FIG. 7
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`Quadrant Ill
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`4600
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`'3200
`-4800
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`-6400
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`7
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`\
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`H ‘0
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`Quadrant IV
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`0956
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`WesternGeco Ex. 1001, pg. 7
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 7 0f8
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`6,026,059
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`6400
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`m0 _-
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`\\
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`(luudruntll
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`//
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`FIG.8
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`-Amp
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`FIG. 9
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`WesternGeco Ex. 1001, pg. 8
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`

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`U.S. Patent
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`Feb. 15,2000
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`Sheet 8 0f8
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`6,026,059
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`1k +Amp
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`FIG. 10
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`FIG. H
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`WesternGeco Ex. 1001, pg. 9
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`

`

`1
`METHOD OF CREATING COMMON
`OFFSET/COMMON-AZIMUTH GATHERS IN
`3-D SEISMIC SURVEYS AND METHOD OF
`CONDUCTING REFLECTION ATTRIBUTE
`VARIATION ANALYSIS
`
`10
`
`15
`
`3O
`
`35
`
`45
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`55
`
`BACKGROUND OF THE INVENTION
`
`This invention relates to the ?eld of seismic signal
`processing, and speci?cally to the area of three dimensional
`seismic signal processing.
`In performing traditional tWo dimensional seismic data
`processing on multiple fold data, common mid-point
`(“CMP”) gathers are made. In comparing the traces in the
`gather, the offset (distance betWeen the source and receiver)
`of the traces varies. Further, in comparing the gather of one
`mid-point to the gather of another midpoint, the number of
`traces and the offset variation is substantially the same. Most
`differences occur due to the need to remove an obviously
`bad trace from the data set. HoWever, in high fold data, such
`blanking is not appreciable.
`In performing three dimensional analysis, rather than
`common mid-point gathers, common mid-point bins are
`made of the data, Which include traces having a common
`midpoint, and various offsets from ray traces having traveled
`cross-line. Such bins might have consistent fold, but uniform
`offset distribution does not eXist. For example, as seen in
`FIG. 1, a typical acquisition geometry for ocean-bottom
`prospecting is seen, in Which tWo receiver lines RLl and
`RL2 are laid out parallel to each other. Sail Lines are shot
`orthogonal to the receiver lines at regular intervals (SL1).
`Referring noW to FIG. 3, nine common-midpoint bins
`(BIN 1—BIN 9) from the survey geometry of FIGS. 1 and 2
`are shoWn, in Which each line Within the bin represents a
`trace, the vertical and horiZontal aXes are offset. Here, it is
`seen that the offset distribution is not uniform. This pattern
`is dependent upon the acquisition geometry, and this non
`uniform pattern has not been found to be avoidable. Chang
`ing the acquisition geometry to accommodate offset distri
`bution in the common mid-point bins is not practical.
`In some forms of analysis, the variation of trace attributes
`as a function of offset or angle of re?ection is of interest
`(e.g., AVO, AVA, and other offset-dependent-re?ectivity
`analysis). HoWever, as seen in FIG. 4, Where one of the
`offset bins of FIG. 3 is seen divided into multiple offset bins
`OB1—OB8, the offset is so non-uniform that offset bins OBl
`includes only one trace and bin OB7 contains thirteen. When
`the traces Within the offset bins are stacked, the large
`variation detrimentally affects the analysis. This occurs
`because the variations created in normaliZing the amplitude
`and noise components of the data, after stacking such
`non-uniform fold, in?uences one of the very attributes to be
`studied—amplitude.
`Accordingly, there is a need for a method of providing
`common-offset bins, Within a common mid-point bin, Which
`are uniform in distribution.
`In conducting amplitude variation With offset analysis
`(“AVO”) and amplitude variation With angle analysis
`(“AVA”), in three dimensional data sets, it is common to
`analyZe the amplitude in a CMP only relative to offset, in a
`tWo-dimensional fashion, and assign a value or slope to the
`variation Within that bin. No aZimuth or directional infor
`mation is preserved that Would indicate the trend of variation
`Within the bin. Therefore, amplitude variation trends across
`a 3D survey are not conducted, and there is a need for a
`method of conducting AVO and/or AVA analysis in Which
`trend information Within the survey bins is available.
`
`6,026,059
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`2
`SUMMARY OF THE INVENTION
`
`It is an object of the present invention to address the above
`problems.
`Therefore, according to one aspect of the invention, a
`method is provided
`A process for generating a bin of common mid-point
`traces from a three dimensional seismic survey data set, each
`of the traces having a shot location and a receiver location
`associated thereWith, the process comprising:
`gathering from the data a plurality of traces having a
`common reference point, Whereby a common reference
`point bin is de?ned and Whereby each of the plurality
`of traces has an offset associated thereWith;
`assigning a coordinate set to a plurality of traces in the
`common reference point bin, Wherein the coordinates
`are associated With the shot position and the receiver
`position associated With the traces and Wherein, from
`the coordinates, the offset and direction of a line
`betWeen the shot and receiver is determinable, Whereby
`a coordinate-designated set of traces is de?ned; and
`organiZing the coordinate-designated set of traces into a
`set of bins having a regulariZed number of traces.
`A process for generating a bin of common mid-point
`traces from a three dimensional seismic survey data set,
`each of the traces having a shot location and a receiver
`location associated thereWith, the process comprising:
`gathering from the data a plurality of traces having a
`common mid-point, Whereby a common mid-point bin
`is de?ned and Whereby each of the plurality of traces
`has an offset associated thereWith;
`assigning a Cartesian coordinate set, having a ?rst axis
`parallel to a receiver line and a second aXis parallel to
`a shot line, to a plurality of traces in the common
`mid-point bin, Wherein the coordinates are associated
`With the shot position and the receiver position asso
`ciated With the traces and Wherein, from the
`coordinates, the offset and direction of a line betWeen
`the shot and receiver is determinable, Whereby a
`coordinate-designated set of traces is de?ned, Wherein
`a plurality of the coordinate-designated set of traces
`have the same coordinates; and
`adding a plurality of traces having the same coordinates.
`A process for providing a data set useful for performing
`analysis of a re?ection attribute of traces in a WindoW of
`three-dimensional seismic data, the process comprising:
`binning the traces into common reference point bins,
`Wherein the traces in the common reference point bins
`represent recordings from shot-receiver pairs having
`various aZimuth angles;
`?tting a surface to the data of the binned traces Within the
`WindoW,
`assigning a coordinate set to the surface, Wherein the
`coordinate set is related to a survey geometry of the
`data.
`A process for providing a data set useful for performing
`analysis of re?ection attribute variation among traces in a
`WindoW of three-dimensional seismic data, Wherein the
`traces have a re?ection point assigned thereto and Wherein
`the traces represent recordings from shot-receiver pairs
`having various aZimuth angles, the process comprising:
`assigning an offset value to a plurality of traces;
`?tting a substantially conical surface having a major and
`a minor aXis to the data of the traces Within the WindoW,
`Wherein:
`
`WesternGeco Ex. 1001, pg. 10
`
`

`

`3
`the major axis of the cone represents the azimuth
`direction having the loWest variation in the re?ection
`attribute, and
`the minor axis of the cone represents the azimuth
`direction having the highest variation in the re?ec
`tion attribute;
`assigning a coordinate set to the surface, Wherein the
`coordinate set is related to a survey geometry of the
`data; and
`comparing the re?ection attribute variation as a function
`of offset and aZimuth.
`
`DESCRIPTION OF THE DRAWINGS
`
`For a more complete understanding of the present inven
`tion and for further advantages thereof, reference is made to
`the following Detailed Description taken in conjunction With
`the accompanying draWings, in Which:
`FIG. 1 is a representational vieW of an example survey for
`acquisition of seismic data.
`FIG. 2 is a representational vieW of an example survey for
`acquisition of seismic data.
`FIG. 3 is a plot of traces in bins formed from the survey
`of FIG. 2.
`FIG. 4 is a plot of one of the bins of FIG. 3.
`FIG. 5 is a set of spider diagram plots of traces in bins
`from the survey of FIG. 2.
`FIG. 6 is a vieW of one of the spider diagram plots of FIG.
`
`5.
`
`FIG. 7 is a spider diagram plot of FIG. 5, divided into
`quadrants.
`FIG. 8 is a spider diagram plot of FIG. 5, Wherein
`opposing plots are added.
`FIG. 9 is a plot of data.
`FIG. 10 is a plot of representational data
`FIG. 11 is a plot of representational data
`It is to be noted, hoWever, that the appended draWings
`illustrate only typical embodiments of this invention and are
`therefore not to be considered limiting of its scope, for the
`invention may admit to other equally effective embodi
`ments.
`Detailed Description of Example Embodiments of
`the Invention
`According to one aspect of the present invention, a
`process is provided for generating a bin of common mid
`point traces from a three dimensional seismic survey data
`set, each of the traces having a shot location and a receiver
`location associated thereWith The process comprises gath
`ering from the data a plurality of traces having a common
`mid-point, Whereby a common mid-point bin (e.g. any of
`bins BIN 1—BIN 9 of FIG. 3) is de?ned and Whereby each
`of the plurality of traces has an offset associated thereWith.
`In FIG. 5, each of the traces of FIG. 3 is shoWn in a spider
`diagram, in Which the offset and aZimuth associated With
`each trace is displayed. The offset is represented by the
`length of the line representing the trace, and the aZimuth is
`represented by the angle of the line. As seen in FIG. 6, Which
`shoWs one of the CMP bins of FIG. 5, a coordinate set is
`assigned to the traces in the CMP bin. In this example, there
`is a constant fold of tWo traces per coordinate bin. Thus,
`from the coordinates assigned, the offset and direction of a
`line betWeen the shot and receiver is determinable, and a
`coordinate-designated set of traces is de?ned.
`In the example embodiment shoWn, a plurality of the
`coordinate-designated set of traces have the same coordi
`
`15
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`nates. In this example, the acquisition geometry resulted in
`tWo traces populating each common-inline/common
`crossline bin, and, according to a further embodiment of the
`invention, such traces are added to increase the signal to
`noise ratio. HoWever, in alternative embodiments, there Will
`be a unique set of coordinates per trace (i.e. a single trace per
`coordinate bin), and no adding Will occur. It should also be
`noted that, in the example of FIG. 6, a Cartesian set of
`coordinates is assigned. HoWever, other sets of coordinates
`are also acceptable, depending upon the pattern and fold of
`the CMP bin.
`Referring noW to FIG. 7, the coordinate bin of FIG. 6 is
`divided into four quadrants (I—IV). It has been found that the
`raypaths for opposing quadrants I and III and quadrants II
`and IV are the same for many acquisition geometries. In a
`geometry as illustrated, the source and receiver locations are
`reversed for opposing quadrants. Accordingly, in one
`embodiment of the invention, as seen in FIG. 8, the Carte
`sian bin is folded such that opposing quadrants are added,
`and common inline/crossline coordinate bins are produced,
`having an increased fold (here, four). It Will be understood
`that in one embodiment of the invention, the Cartesian
`coordinates have a ?rst axis parallel to a receiver line and a
`second axis parallel to a shot line; While, according to an
`alternative embodiment, the Cartesian coordinates have a
`?rst axis parallel to a shot line and a second axis parallel to
`a receiver line.
`According to a further aspect of the present invention, a
`process is provided for generating a data set useful for
`performing analysis of re?ection attribute (e.g. amplitude,
`frequency, phase) variation among traces. According to this
`aspect, it has been found that re?ection attributes for the
`same re?ection point vary, depending upon the raypath
`being detected. In some embodiments, the variation is
`analyZed by comparing the variation to the offset betWeen
`the shot and the receiver detecting the re?ection event;
`While, in other embodiments, the variation is compared as a
`function of the re?ection angle at the event In any case, on
`seismic data, thought to be re?ected from the same location
`in the subsurface. In fact, the seismic data represents dif
`ferent offsets or angles of incidence. In such a point in one
`volume, the traces have a common reference assigned to
`them, and the traces represent recordings from shot-receiver
`pairs having various aZimuth angles. Therefore, according to
`one embodiment of this aspect of the invention, the process
`comprises: ?tting a surface to the data of the traces Within
`the WindoW and assigning a coordinate set to the surface,
`Wherein the coordinate set is related to a survey geometry of
`the data. It has been found that a ?rst order interpolation of
`the re?ection attribute variation among the data is suf?cient
`for many applications, although higher order interpolations
`Will also suf?ce.
`Referring noW to FIG. 9, as knoWn in the art of tWo
`dimensional AVA analysis, a “best ?t” line can be calculated
`having a y-axis of amplitude of traces Within a WindoW, an
`x-axis of angle of re?ection, and a slope, representing the
`variation of amplitude With angle of incidence. To date,
`hoWever, three-dimensional AVA or AVO analysis has not
`been useful, due in part to the lack of ability to provide
`aZimuth information and to reduce the inconsistency in fold.
`According to one embodiment of the present invention,
`hoWever, three-dimensional analysis is made possible.
`As seen in FIG. 10, a ?rst order approximation of a
`surface ?t to the amplitude of traces in the bin of FIG. 8 is
`a cone, using a non-linear least squares algorithm. In cases
`in Which there is an anisotropic effect to the amplitude
`response, the cone Will be distorted into an elliptical cone,
`
`WesternGeco Ex. 1001, pg. 11
`
`

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`15
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`25
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`5
`having a semi-minor axis “a” and a semi-major axis “b”
`(FIG. 11). According to this embodiment, the semi-major
`axis is aligned With the azimuth of minimum gradient, and
`the semi-minor axis is aligned With the aZimuth of maximum
`gradient. Therefore, FIG. 11 is an example in Which the
`major axis of the cone represents the aZimuth direction
`having the loWest gradient in the re?ection attribute, and the
`minor axis of the cone represents the aZimuth direction
`having the highest gradient in the re?ection attribute. In
`alternative embodiments, this convention is reversed.
`Further, it should be noted that in one embodiment of the
`process just described, the common reference comprises a
`common mid-point; While, in embodiments in Which dip
`moveout or migration algorithms are applied, the common
`reference comprises a common-re?ection point.
`In any case, according to a further aspect of the invention,
`offset values Which have been assigned to a plurality of
`traces, and the re?ection attribute variation betWeen traces in
`the WindoW are compared as a function of offset and
`aZimuth. Again, in one example, the re?ection attribute
`comprises amplitude. HoWever, in other embodiments, fre
`quency and/or phase is the re?ection attribute under analy
`sis. According to still further embodiments, instantaneous
`amplitude, instantaneous frequency, and/or instantaneous
`phase are vieWed as a function of aZimuth.
`Further still, in some embodiments the amplitude attribute
`analyZed is p-Wave amplitude, While in other embodiments
`the attribute analyZed comprises s-Wave amplitude. Phase
`and frequency attributes of p-Wave and s-Waves are analyZed
`according to still further embodiments.
`According to still further embodiments of the invention,
`the aZimuth information made available is used to vieW
`trends of re?ection attribute behavior across the survey. For
`example, in one embodiment, the AVO response of CMP
`bins is compared. Thus, generally stated, a data set of
`multiple bins of traces is provided, Wherein a plurality of
`traces in the bin have a common reference assigned thereto
`and Wherein the traces represent recordings from shot
`receiver pairs having various aZimuth angles. A surface is ?t
`to the data of the traces Within the WindoW, in each of the
`bins; a coordinate set is assigned to a plurality of the
`surfaces; and the surfaces of adjacent bins are tied.
`The above embodiments are provided by Way of example
`only, and alternative embodiments Will occur to those of
`skill in the art Without departing from the spirit of the
`invention, as de?ned by the claims beloW.
`What is claimed is:
`1. A process for generating a bin of common mid-point
`traces from a three dimensional seismic survey data set, each
`of the traces having a shot location and a receiver location
`associated thereWith, the process comprising:
`gathering from the data a plurality of traces having a
`common reference point, Whereby a common reference
`point bin is de?ned and Whereby each of the plurality
`of traces has an offset associated thereWith;
`assigning a coordinate set to a plurality of traces in the
`common reference point bin, Wherein the coordinates
`are associated With the shot position and the receiver
`position associated With the traces and Wherein, from
`the coordinates, the offset and direction of a line
`betWeen the shot and receiver is determinable, Whereby
`a coordinate-designated set of traces is de?ned; and
`organiZing the coordinate-designated set of traces into a
`set of bins having a regulariZed number of traces.
`2. A process as in claim 1 Wherein a plurality of the
`coordinate-designated set of traces have the same coordi
`nates.
`
`50
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`6,026,059
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`6
`3. A process as in claim 2, further comprising adding a
`plurality of traces having the same coordinates.
`4. Aprocess as in claim 1, Wherein each trace has a unique
`set of coordinates.
`5. A process as in claim 1, Wherein at least tWo of the
`coordinate-designated set of traces have different coordi
`nates and are from a common shot-receiver location, and
`further comprising adding the at least tWo of the coordinate
`designated set of traces.
`6. Aprocess as in claim 1 Wherein the coordinate set is a
`Cartesian coordinate set.
`7. A process as in claim 6 Wherein the Cartesian coordi
`nate set has a ?rst axis parallel to a receiver line and a second
`axis parallel to a shot line.
`8. A process as in claim 6 Wherein the Cartesian coordi
`nate set has a ?rst axis parallel to a shot line and a second
`axis parallel to a receiver line.
`9. A process as in claim 6 Wherein the Cartesian coordi
`nates set has a ?rst axis parallel to a receiver line and a
`second axis parallel to a shot line.
`10. Aprocess as in claim 1 Wherein the common reference
`point comprises a common midpoint.
`11. Aprocess as in claim 1 Wherein the common reference
`point comprises a common re?ection point.
`12. Aprocess for generating a bin of common mid-point
`traces from a three dimensional seismic survey data set, each
`of the traces having a shot location and a receiver location
`associated thereWith, the process comprising:
`gathering from the data a plurality of traces having a
`common mid-point, Whereby a common mid-point bin
`is de?ned and Whereby each of the plurality of traces
`has an offset associated thereWith;
`assigning a Cartesian coordinate set, having a ?rst axis
`parallel to a receiver line and a second axis parallel to
`a shot line, to a plurality of traces in the common
`mid-point bin, Wherein the coordinates are associated
`With the shot position and the receiver position asso
`ciated With the traces and Wherein, from the
`coordinates, the offset and direction of a line betWeen
`the shot and receiver is determinable, Whereby a
`coordinate-designated set of traces is de?ned, Wherein
`a plurality of the coordinate-designated set of traces
`have the same coordinates; and
`adding a plurality of traces having the same coordinates.
`13. Aprocess for providing a data set useful for perform
`ing analysis of a re?ection attribute of traces in a WindoW of
`three-dimensional seismic data, the process comprising:
`binning the traces into common reference point bins,
`Wherein the traces in the common reference point bins
`represent recordings from shot-receiver pairs having
`various aZimuth angles;
`?tting a surface to the data of the binned traces Within the
`WindoW;
`assigning a coordinate set to the surface, Wherein the
`coordinate set is related to a survey geometry of the
`data.
`14. A process as in claim 13 Wherein the surface repre
`sents a ?rst order interpolation of the re?ection attribute
`variation among the data.
`15. A process as in claim 13 Wherein the common
`reference comprises a common mid-pit.
`16. A process as in claim 13 Wherein the common
`reference comprises a common-re?ection point.
`17. A process as in claim 13 Wherein the surface com
`prises a cone, having a major and a minor axis.
`18. Aprocess as in claim 17 Wherein the major axis of the
`cone represents the aZimuth direction having the loWest
`variation in the re?ection attribute.
`
`WesternGeco Ex. 1001, pg. 12
`
`

`

`re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`re?ection
`
`7
`19. Aprocess as in claim 18 wherein the minor axis of the
`cone represents the azimuth direction having the highest
`variation in the re?ection attribute and Wherein the length of
`the semi-major aXis is different from the length of the
`semi-minor aXis.
`20. A process as in claim 13 further comprising:
`assigning an offset value to a plurality of traces and
`comparing the re?ection attribute variation as a function
`of offset and aZimuth.
`21. A process as in claim 20 Wherein the
`attribute comprises amplitude.
`22. A process as in claim 21 Wherein
`attribute comprises p-Wave amplitude.
`23. A process as in claim 21 Wherein
`attribute comprises s-Wave amplitude.
`24. A process as in claim 20 Wherein
`attribute comprises frequency.
`25. A process as in claim 24 Wherein
`attribute comprises p-Wave frequency.
`26. A process as in claim 24 Wherein
`attribute comprises s-Wave frequency.
`27. A process as in claim 20 Wherein
`attribute comprises phase.
`28. A process as in claim 27 Wherein
`attribute comprises p-Wave phase.
`29. A process as in claim 27 Wherein the
`attribute comprises s-Wave phase.
`30. A process as in claim 13 further comprising:
`assigning a re?ection angle to a plurality of traces and
`comparing the re?ection attribute variation as a function
`of re?ection angle and aZimuth.
`31. A process as in claim 30 Wherein the
`attribute comprises amplitude.
`32. A process as in claim 31 Wherein
`attribute comprises p-Wave amplitude.
`33. A process as in claim 31 Wherein
`attribute comprises s-Wave amplitude.
`34. A process as in claim 30 Wherein
`attribute comprises frequency.
`35. A process as in claim 34 Wherein
`attribute comprises p-Wave frequency.
`36. A process as in claim 30 Wherein
`attribute comprises s-Wave frequency.
`37. A process as in claim 30 Wherein
`attribute comprises phase.
`38. A process as in claim 37 Wherein
`attribute comprises p-Wave phase.
`39. A process as in claim 37 Wherein the
`attribute comprises s-Wave phase.
`40. A process as in claim 13 further comprising:
`providing a data set of multiple bins of traces Wherein a
`plurality of traces in the bin have a common reference
`assigned thereto and Wherein the traces represent
`recordings from shot-receiver pairs having various aZi
`muth angles;
`
`re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`the re?ection
`
`re?ection
`
`10
`
`15
`
`35
`
`45
`
`55
`
`6,026,059
`
`8
`?tting a surface to the data of the traces Within the
`WindoW, in a plurality of the bins;
`assigning a coordinate set to a plurality of the surfaces;
`and
`tying the surfaces of adjacent bins.
`41. A process as in claim 40, Wherein:
`said ?tting comprises ?tting a cone to the date,
`Wherein the cone has a semi-major aXis and a semi-minor
`axis,
`Wherein the length of the semi-major aXis is dependent
`upon the gradient of re?ection attribute variation in a
`?rst direction,
`the length of the semi-minor aXis has a length dependent
`upon the gradient of re?ection attribute variation in a
`second direction,
`said tying comprises de?ning a trend of re?ection
`attribute variation betWeen a plurality of bins of traces,
`a plurality of traces in any single bin have a common
`reference With the other traces in the single bin, and
`the trend is dependent upon the minor and major aXes of
`a plurality of bins.
`42. Aprocess for providing a data set useful for perform
`ing analysis of re?ection attribute variation among traces in
`a WindoW of three-dimensional seismic data Wherein the
`traces have a re?ection point assigned thereto and Wherein
`the traces represent recordings from shot-receiver pairs
`having various aZimuth angles, the process comprising:
`assigning an offset value to a plurality of traces;
`?tting a substantially conical surface having a major and
`a minor aXis to the data of the traces Within the WindoW,
`Wherein:
`the major aXis of the cone represents the aZimuth
`direction having the loWest variation in the re?ection
`attribute, and
`the minor aXis of the cone represents the aZimuth
`direction having the highest variation in the re?ec
`tion attribute;
`assigning a coordinate set to the surface, Wherein the
`coordinate set is related to a survey geometry of the
`data; and
`comparing the re?ection attribute variation as a function
`of offset and aZimuth.
`43. A process as in claim 42 further comprising:
`providing a data set of multiple bins of traces Wherein a
`plurality of traces in the bin have a common re?ection
`point and Wherein the traces represent recordings from
`shot-receiver pairs having various aZimuth angles;
`?tting a surface to the data of the traces Within the
`WindoW, in a plurality of the bins;
`assigning a coordinate set to a plurality of the surfaces;
`and
`tying the surfaces of adjacent bins.
`
`*
`
`*
`
`*
`
`*
`
`*
`
`WesternGeco Ex. 1001, pg. 13
`
`