`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://librarysegorg/
`
`
`
`
`
`
`
`GEOPHYSICS, VOL. 55, NO. 10 (OCTOBER 1990); P. 1389—1396, 15 FIGS.
`
`Encoding techniques for multiple source point seismic data acquisition
`
`J. E. Womack*, J. R. Cruz*, H. K. Rigdoni, and G. M. Hoover:
`
` ABSTRACT
`
`Recent advances in vibrator electronics have made the
`use of encoded sweeps for multiple source point data
`acquisition possible in an operational setting. Alternatives
`to existing operational multiple source point data acquisi-
`tion techniques, using complementary series and E-codes,
`are developed in this paper.
`Most existing techniques are, at each source point, a
`series of linear sweeps of predetermined polarity that
`enables the cancellation of the contributions from the
`other source points in processing. The complementary
`series techniques developed here also choose polarities
`such that the contributions from other source points can
`be cancelled. Pairs of E-codes have been found that pro-
`duce no crosscorrelation, which makes it possible to use
`E-codes to produce a dual source point technique that is
`fundamentally different
`from the more conventional
`techniques.
`Field tests are carried out using E~codes in dual source
`point schemes. Records from the respective source points
`are readily separated from the composite data collected
`and compared with records produced by a linear sweep
`from a single s0urce point. Harmonic distortiOn appears
`to be the major limiting factor; however, record quality
`indicates that E—codes can be used in operational multi—
`ple source point data acquisition.
`
`
`
`
`INTRODUCTION
`
`For over a decade there have been efforts to develop vibrator
`signals for seismic data acquisition schemes that allow more than
`one source point to be recorded simultaneously. In certain cases,
`such as vertical seismic profiling (VSP) and 3-D data acquisi-
`tion, the additional costs of data processing, field—crew members,
`and hardware for simultaneous source point acquisition are
`economically justifiable.
`
`Most existing multiple source point acquisition techniques rely
`on the use of linear sweeps of differing phase polarities. One
`such technique assigns to each source point a sequence of
`upsweeps, each of positive or negative phase polarity (Silverman,
`1979). The idea behind this technique is to remove the signal
`due to all other source points by cancelling their contributions
`in the vertical stacking process. In practice, there is never com-
`plete cancellation because surface conditions differ and vibrator
`hardware cannot reproduce all sweeps identically. An extension
`to this technique that helps reduce these effects includes down-
`sweeps of opposite polarities as source point signals (Garotta,
`1983).
`Sometimes record degradation from these two techniques
`is of unacceptable levels. Therefore, investigations into new
`vibrator signals for use in multiple source point data acquisi—
`tion continue. Here we discuss two sweep encoding techniques
`that have been introduced as ways to reduce record correlation
`noise (Bernhardt et al., 1978; Edelman et al., 1983) as possible
`signals for use in multiple source point data acquisition (Womack
`et al., 1988).
`
`ENCODING SWEEPS FOR MULTIPLE SOURCE POINT SIGNALS
`
`The choice of upsweeps and downsweeps as signals for use
`in multiple source point recording is natural since these are the
`most commonly used signals in conventional rec0rding. Also,
`vibrators are specifically designed to generate these signals.
`Recent vibrator electronics technology has made vibrators that
`generate a sequence of sweeps with no listening period between
`sweeps readily available. Proper encoding of such a sequence
`of sweeps provides a vibrator realization of complementary series
`(Golay, 1961) and E-codes (Welti, 1960) as shown in Figure 1.
`These codes have been investigated for use in data acquisition
`by Bernhardt and Peacock (1978).
`Each code of these encoding techniques consists of two
`separate sequences. They possess the property that if the auto-
`correlation of the first sweep-encoded sequence of the pair is
`added to that of the second sequence, a resulting correlation
`
`Manuscript received by the Editor January 13, 1989; revised manuscript received May 9. 1990.
`‘School of Electrical Engineering and Computer Science, Unlverslty of Oklahoma, 202 West Boyd, Norman, OK 73019.
`iPhillips Petroleum Company, Bartlesville, OK 74004.
`@1990 Society of Exploration Geophysicists. All rights reserved.
`
`1389
`
`WesternGeco Ex. 1013, pg. 1
`
`WesternGeco Ex. 1013, pg. 1
`
`

`

`
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://librarysegorg/
`
`
`
`
`
`
`
`1390
`
`Womack et al.
`
`“comm; flcmlqm
`
`ENCODING TECHNIQUES
`
`
`SEQUENCE l
`SEQUENCE 2
`
`M W
`
`
`Ml “4 3:7)
`
`FIG. 1. Examples of a 4-bit complementary series code pair
`(top) and of a 4-bit E-code pair (bottom). The upward slope
`of the line in each element signifies an upsweep and downward
`slope a downsweep. The + and —— in the circles indicate the
`polarity of the sweep. Each sweep is tapered.
`
`ENCODING TECHNIQUES
`
`SWEE P LACS
`
`FIG. 3. The autocorrelation of the 4-bit E-code sequences in
`Figure 1: sequence 1 (top), sequence 2 (middle), the sum of the
`two autocorrelations (bottom).
`
`:Nconnlc TECHNIQUES
`
`
`
`
`mum (2)532sz
`(ZXZXZXF‘
`(ZXZXZXZr
`a
`6?:cm I
`new I2
`'
`mm I
`I
`mm 22
`
`I
`—4
`
`I
`—5
`
`I
`—2
`
`I
`I
`I
`1
`o
`—1
`SWEEP LACS
`
`I
`2
`
`I
`3
`
`I
`t
`
`FIG. 4. Sequenceof codes for dual source point data acquisition
`usmg 4-bit complementary series.
`
`FIG. 2. The autocorrelation of the 4—bit complementary series
`sequences in Figure 1: sequence 1 (top), sequence 2 (middle),
`the sum of the two autocorrelations (bottom).
`
`wavelet confined to a time period twice the length of the sweeps
`used to realize the code is produced (Edelman et al., 1982). This
`can be observed in Figures 2 and 3. The bandwidth and tapers
`on each sweep in the encoded sequence will have a similar impact
`as on conventional sweeps.
`Complementary series are binary codes that can be realized
`with either linear or nonlinear upsweeps or downsweeps of a
`positive or negative polarity. If, for a dual-source scheme, two
`complementary series whose first sequences have a crosscorrela-
`tion equal and opposite to that of the second sequences could
`be found, then, by simple correlation with the proper reference
`before stacking, records from the individual source points would
`be recovered. Two complementary series with this property have
`yet to be found.
`
`However, these codes can still be used; an example for dual
`source point data acquisition is shown in Figure 4. As can be
`seen, four encoded sweeps will be applied at both source points
`1 and 2. It is clear that the last two sweeps for source point 2
`are merely phase—inverted versions of the first two. Therefore,
`this scheme is, in principle, equivalent to the Silverman tech-
`nique of cancelling the contributions of the signals from the
`other source points through vertical stacking. That
`is, by
`adding record 11 to record 21 and assuming that phase-inverted
`sweeps can be perfectly generated, then the contribution of
`source point 2 will be eliminated.
`Since vibrators have difficulty reproducing simple sweeps, it
`is unlikely that the more complicated encoded sweeps could be
`reproduced any better. However, if the errors in the reproduc-
`tion of sweeps are random, it may be possible for the encoded
`sweep, since it uses many short encoding sweeps, to reduce
`contributions from other source points in the correlation pro-
`cess. In such conditions, this benefit would have to be weighed
`against the problem of harmonic distortion almost certain to
`pose problems because of the short encoding sweeps used in the
`
`WesternGeco Ex. 1013, pg. 2
`
`WesternGeco Ex. 1013, pg. 2
`
`

`

`Encoding Techniques
`
`1391
`
`can still suffer from harmonic distortion as with the complemen-
`tary series. Problems with harmonic distortion can be combated
`by making the encoding sweeps as long as possible. These effects
`may also be minimized by using harmonic distortion-reduction
`techniques (Martinez et al., 1987).
`
`FIELD TESTING
`
`Theoretical and modeling studies of complementary series
`and E—code encoding schemes previously described indicate that
`E-code techniques may be superior for dual source point record-
`ings. Field tests were performed using E-code techniques for fur—
`ther evaluation of these encoding schemes.
`Figure 7 shows the recording geometry used to field test the
`E-code techniques. Two vibrators, separated by 300 ft (91.5 m),
`were simultaneously recorded by a clamped downhole geophone
`at 500 ft (152.4 m) and by a series of surface geophones. Both
`the 4—bit and the 8—bit E—codes were tested.
`
`ie———— 300‘ —-|
`T vazale
`alevm T
`
`
`
`bO
`m
`
`TR1 o T -l-
`12‘
`O _.L
`
`_
`a
`_
`
`SURFACE
`RECEIVER
`SPREAD
`
`O| |
`
`I
`:
`
`Ioo
`
`o
`DOWNHOLE
`PHONE
`
`
`
`bs
`
`:
`
`l
`
`TR96 O
`
`_I_
`
`field acquisition geometry for
`FIG. 7. Plane view of
`simultaneous vibrator testing.
`
`Records were generated from the vibrator located 900 ft (274.4
`m) off-end from the surface spread (VBl) and from a second
`vibrator
`(VB2), both using conventional
`(uncoded)
`linear
`downsweeps. Records were also generated with the vibrators
`operating simultaneously using E-code sweeps. The downhole
`geophone records are shown in Figure 8. The sweeps used for
`the encoded sweeps were 3.5 5 linear upsweeps and downsweeps
`over a frequency range of 10—96 Hz. A 0.2 s cosine-squared taper
`was applied to both ends of the sweeps. The conventional sweep
`was a 14 5 linear downsweep over the 10—96 Hz bandwidth
`and also used a 0.2 s taper. A sum of four sweeps for both the
`sequential and simultaneous sources was used for each record.
`The downhole comparisons indicate that the encoded sweep
`records extracted have visually identical waveforms to the
`conventional sweep records for both vibrator locations. Di ffer—
`
`WesternGeco Ex. 1013, pg. 3
`
`encoding process. Also, the additional storage costs of doubling
`the amount of field data, if the records are stacked in the field,
`and increasing processing by one correlation per source point
`have to be considered.
`
`For complementary series, the ill effects of error in sweep
`reproduction will be most prominent in the source wavelet
`around one encoding sweep width (see Figure 2). This will show
`up in the data as a multiple and can possibly be removed by
`standard multiple-removal
`techniques or by choosing the
`encoding sweeps to be longer, thereby moving the multiple down
`in the record. Also, in an extension to this technique, complemen-
`tary series can use codes comprising upsweeps at some source
`points and codes comprising downsweeps at others, as suggested
`by Garotta (1983).
`E-codes are quaternary codes and must be realized with
`upsweeps and downsweeps of both polarities. Pairs of E—codes,
`unlike complementary series, have been found such that the
`crosscorrelation of the first sequences added to the cross-
`correlation of the second sequences is zero. Therefore, encoding
`techniques can be devised (see Figure 5) using E-codes that are
`fundamentally different from any technique that cancels the
`contributions of other source points through phase inversion
`of sweeps.
`
`ENCODING TECHNIQUES
`
`
`
`. “WKXXXPQ— wowm .
`
`,
`
`w EEQZXE— Egg/37
`ll
`1
`H
`’
`
`I
`
`RECORD 1
`
`RECORD 2
`
`FIG. 5. Sequence of codes for dual source point data acquisition
`using 4-bit E-codes.
`
`ENCODING TECHNIQUES
`
`51:01. Nos 1
`SEourNcE I
`W’ m
`
`code pan #1
`
` ‘E U N F 7 SEQUkN k 7 WmWWW
`”W“ EMS) ‘
`nauhhaaa
`
`FIG. 6. The 8-bit E-code pairs whose crosscorrelations between
`code 1 of each pair and between code 2 of each pair sum to zero.
`
`There are only four 4-bit and eight 8—bit E-codes. From these
`there is a pair of 4-bit codes and two pairs of 8-bit codes which
`satisfy this property. The 4—bit codes are exhibited in Figure 5
`and two 8-bit pairs are shown in Figure 6. Through record
`cancellation, E-codes can be extended to encompass more source
`points than this dual source point scheme.
`One advantage of E-codes over the complementary series is
`that the residual in the source wavelet caused by imperfect sweep
`reproduction by the vibrators will not be prominent around one
`encoding sweep width, and will not,
`therefore, cause the
`problems with multiples of the complementary series. E-codes
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://librarysegorg/
`
`
`
`
`
`
`
`
`
`WesternGeco Ex. 1013, pg. 3
`
`

`

`
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://library.seg.org/
`
`
`
`
`
`
`
`1392
`
`Womack et al.
`
`NUPHRL
`
`% all
`
`8 BIT
`
`VlB i
`
`m
`
`m
`
`m
`
`m
`
`m
`
`H
`
`.S
`
`.E
`
`.7
`
`l
`
`.1
`
`, ‘H‘ “U. .AAfifi fiffif Afr»
`J'lpVylu.‘.
`- Jul MA. .1. NH .
`Vvyt\--‘.‘
`,4, if“ N}, NM .NH N
`r,'t,t.\v.
`.E
`.3
`.H
`.S
`.S
`
`1
`
`.1
`.5
`.8
`.1 sac
`,
`I
`CONVENTIONAL SWEEP VIB #1
`
`.E
`
` 4-BIT E<CODE VIB #1
`
`8
`
`5
`
`.1
`
`E
`
`3
`
`N
`
`8-BIT E-CODE V13 #1
`
`mums.)
`
`NORMAL
`
`* HIT
`
`E Bll
`
`V15 2
`
`1
`
`E
`
`3
`
`.W
`
`5
`
`S
`
`.1
`
`5
`s
`
`s
`
`a
`
`a
`
`AAA AA ‘J‘ *A/‘l‘t‘ «Mm/VA
`A!) JANA} fi/‘fif M!
`
`A” My” MM M!
`/
`.E
`.5
`.H
`
`.1
`
`.5
`
`.E
`
`.E
`
`.3
`
`.1
`
`.2
`
`.3
`
`.H
`
`1 SEC
`CONVENTIIONAL SWEEP VIB '#2
`
`4-BlT E-CODE VIB #2
`
`B-BIT E-CODE VIB #2
`
`
`
`mew)
`
`FIG. 8. The signals received at the downhole geophone from VBl (top) and VB2 (bottom) with the vibrator sweeps
`being: linear sweeps applied separately, 4—bit E—code sweeps applied simultaneously, and 8-bit E-code sweeps applied
`simultaneously.
`
`ences in signature shapes between the vibrator positions are
`attributed to differences in base-plate coupling.
`Figure 9 compares power spectra of the downhole recordings.
`These plots indicate that
`the records extracted from the
`simultaneous encoded sweeps and from the sequential uncoded
`sweeps have nearly identical power spectra.
`Figures 10—12 show records from the surface geophones using
`the same source vibrator parameters as Figures 7—9. Figure 10
`shows the single vibrator (VB2) conventional sweep record.
`Figures 11 and 12 show the extracted VB2 records for the
`simultaneously recorded sweeps using the 4—bit and 8-bit E—codes,
`respectively. Each trace of the surface-spread records was
`acquired with a single 10 Hz geophone A 25—90 Hz band-
`pass filter has been applied to attenuate strong surface wave
`events and to enhance the reflection events for better comparison.
`A comparison of Figures 11 and 12 shows that the extracted
`4-bit and 8-bit E-code records are in good agreement and that
`both are similar to the sequential, standard-sweep record. Major
`coherent events (surface waves, air waves, reflection events, and
`reverberations) apparent on the conventional sweep recording
`are very similar on the 4-bit and 8-bit encoded recordings.
`Reflection events near 2000 ft
`(610 m) offset appear to
`demonstrate improved signal-to—noise ratio at reflection times
`
`of 0.98 s on the E-code records. A major difference between
`the conventional and E—coded records is the presence of a low-
`frequency event on the E—code measurements which does not
`appear on the conventional recording. This event tracks the
`surface wave in offset and time with a time delay of about 400
`ms and indicates that it is a correlation ghost associated with
`the upsweeps in the E-code sweep. A comparison of Figures 11
`and [2 indicates that correlation ghost noise is stronger on the
`4—bit E-code record. However, it is difficult to distinguish be-
`tween the effects of ghosting and the strong reverberations.
`TWO-dimensional power spectra of the surface-recorded
`records in Figure 10—12 are shown in Figures 13—15. Maximum
`power levels are indicated by the darkest shading, and power
`levels of —60 dB are represented by the lightest area. The time
`transform was limited to a 0.4 to 0.8 5 window.
`Analysis of the f-k spectra indicates that the E—code records
`have similar power spectral properties to the conventional sweep
`record. The E-code records appear to contain a slightly greater
`proportion of energy with sweep velocities corresponding to
`signal, reverberation, or surface waves in the 30—75 Hz band-
`width. This indicates a slightly larger coherent-to-background
`noise ratio for the E-code records. However, it is difficult to ascer-
`tain whether this benefit can be realized in operational use.
`
`WesternGeco Ex. 1013, pg. 4
`
`WesternGeco Ex. 1013, pg. 4
`
`

`

`
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://libraqrsegorg/
`
`
`
`
`
`
`
`Encoding Techniques
`
`1393
`
`FREQUENCY (Hz)
`4o
`50
`so
`70
`
`20
`
`30
`
`so 90
`
`100
`
`0
`
`10
`
`20
`
`30
`
`FREQUENCY (Hz)
`40 50
`60
`70
`
`80
`
`90100HERTZ
`
`
`
`CONVENTIONAL SWEEP
`
`VIB #2
`
`
`
`
`
`
`
`
`
`10 100 HERTZ 20 30 40 50 60 70 80 90
`
`
`
`
`
`
`
`
`
`
`
`
`VIB #1
`
`0
`
`10
`
`20
`
`30 40
`
`50 60 70
`
`80
`
`90 100
`
`
`
`
`
`
`
`(db)
`
`
`
`
`POWER
`
`VIB #1
`
`4—BIT E—CODE
`
`VIB #2
`
`0
`
`10
`
`20
`
`30
`
`40
`
`50 60
`
`70
`
`80 90100
`
`0
`
`10
`
`20
`
`30 40 50
`
`60
`
`70
`
`80 90
`
`100 HERTZ
`
`VIB #1
`
`B-BIT E-CODE
`
`VIB #2
`
`FIG. 9. Power spectra for the signals shown in Figure 8.
`
`CONCLUSIONS
`
`A significant residual in the source wavelet at one encoding
`sweep width using complementary series may result and cause
`a multiple in the data of one encoding sweep width. The
`multiples will be more prominent in the data that are deeper
`and at farther offsets.
`E-code techniques do not produce a prominent residual in the
`source wavelet located around one encoding sweep width and
`do not rely on source point cancellation techniques. For this
`reason, E-codes are considered, for most uses, the most prom-
`
`ising of the two encoding techniques introduced here for
`multiple source point acquisition. The field tests show that
`records can be readily separated using 4-bit and 8-bit E—codes
`for the dual source point scheme. A slightly larger coherent—to-
`background noise ratio in records obtained with E-codes as
`compared to conventional single source recording was evident.
`Record degradation due to the effects of relatively large
`encoding sweep tapers required to implement E-code techniques
`was not noticeable in the field test data but requires further
`investigation. The major limiting factor in these techniques may
`be the ill effects of harmonic distortion on records due to the
`
`WesternGeco Ex. 1013, pg. 5
`
`WesternGeco Ex. 1013, pg. 5
`
`

`

`
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://librarysegorg/
`
`
`
`
`
`
`
`1394
`
`Womack et al.
`
`use of short encoding sweeps. Collection of data at greater
`_
`_
`_
`_
`depths lS requ1red to better define the relative strengths and
`weaknesses of E-codes and conventional sweep technologies;
`however, there are indiwtions that Ecodes can be used in opera—
`tional multiple source point data acquisition.
`
`ACKNOWLEDGMENTS
`
`The authors would like to thank Tom Thomas of Phillips
`Petroleum Co. for his time and efforts in processing the field
`data.
`
`WAC? OFFsEY 4H»
`
`TRACE OFFSEY (FT)
`
`.
`
`$3
`
`Islam;
`
`(SlinA
`{REEL
`
`FIG. 10. Record recorded with surface geophone spread using
`VBZ with conventional linear downsweep.
`
`11. Record extracted for VBZ recorded with surface
`FIG.
`geophone spread using both VBl and VBZ and 4-bit E-code
`sweeps.
`
`TRACE OFFSET [F‘H
`
`“ ‘-
`.
`-
`.
`Ecnon EvEms wt
`
`FIG. 12. Same as Figire 11 using 8-bit E—code sweeps.
`
`WesternGeco Ex. 1013, pg. 6
`
`WesternGeco Ex. 1013, pg. 6
`
`

`

`Encoding Techniques
`
`1395
`
`0 to -6db
`-7 to -126b
`-13 (o -18db
`
`
`
`mm
`0t0
`
`.11._
`
`739
`
`19....
`
`000
`
`..
`113.
`
`
`
`awn23w
`
`
`
`-19 IO -24db
`
`
`ANT:>Ozw30wmmANT:>02w30wmuwmwwwwmm
`\mhomoméfiagfifiE95wemanual08MEWFEOQHo3:8:OmE880.3%nousnabmnvom+2.3.9:.mom3SEQ:8303309
`31%.].M4.W16Mlam
`
`F)nn..\k/.m.m
`
`EmmfiFbmfi
`my”mgnAwnmnwmm“.
`
`
`mammwmgmwe,MW],WWWWsl
`arommumm
`
`Mmmw.momw
`PFmFPFm
`
`
`
`‘o.x2qo2:.on:.
`
`WAVELENGTH (FT)
`
`WesternGeco Ex. 1013, pg. 7
`
`WesternGeco Ex. 1013, pg. 7
`
`
`

`

`
`
`
`
`
`
`Downloaded11/25/14to208.185.19.234.RedistributionsubjecttoSEGlicenseorcopyright;seeTermsofUseathttp://librarysegorg/
`
`
`
`
`
`
`
`1396
`
`Womack et al.
`
`REFERENCES
`
`Bernhardt, T., and Peacock, J. H., 1978, Encoding techniques for the
`Vibroseis system: Geophys. Prosp., 26, 184-192.
`Edelman, H. A. K., and Werner, H., 1982, Combined sweep signals for
`
`correlation noise suppression: Geophys. Prosp., 30, 786—812.
`The encoded sweep technique for Vibroseis: Geophysics, 47,
`809—818.
`7
`Garotta, R., 1983, Simultaneous recording of several Vibroseis seismic
`lines: 45th Eur. Assn. Expl. Geophys., Expanded Abstracts, 3S; and
`53rd Ann. Internat. Mtg., Soc. Explor. Geophys, Expanded Abstracts,
`308—310.
`
`Golay, M. J. E., 1961, Complementary series: Inst. Radio Eng. Trans.
`Inf. Theory, 7, 82—87.
`Martinez. D. R. and Crews. G. A., 1987. Evaluation of simultaneous
`Vibroseis recording: 57th Ann. Internat. Mtg., Soc. Expl. Geophys.,
`Expanded Abstracts, 577-580.
`Silverman, D., 1979, Method of three-dimensional seismic prospecting:
`US. patent 4 159 463.
`Welti, G. R., 1960, Quaternary codes for pulsed radar: Inst. Radio Eng.
`Trans. Inf. Theory, 6, 400—408.
`Womack, J. E., Cruz, J. R., Rigdon, H. K., and Hoover, G., 1988,
`Simultaneous Vibroseis encoding techniques: 58th Ann. Internat. Mtg.,
`Soc. Exp]. Geophys., Expanded Abstracts, 101—104.
`
`LEGEND
`0 to -6db
`-7 to -12db
`~13 to 4811)
`-19 to -24db
`~25 to -30db
`-31 to -36db
`-37 10 -4Zdb
`43 to 48d:
`-49 to -54db
`
`UNI
`[JXII—o
`
`. .1
`u on...
`
`
`
`FREQUENCY1H2)
`
`
`
`
`
`133
`
`:~-‘
`
`153
`
`‘s
`
`s:
`
`as
`
`a:
`
`“
`
`5:
`
`:9
`
`:‘
`
`z<
`
`WAVELENGTH (FT)
`
`FIG. 15. Frequency-wavenumber (f-k) power spectrum of record in Figure 12, 0.4—0.8 s time window.
`
`WesternGeco Ex. 1013, pg. 8
`
`WesternGeco Ex. 1013, pg. 8
`
`

`

`11/252014
`
`Encoding techniqus for m uli pie 5 outce points eis mic data acquis ifi on : G EDP HYSIC 8: Vol. 56. N o. 10 (Society of Exploration 6 eophys icist)
`
`Donate | Careers | Community | Shog | Register | Sign In
`SEG DIGITAL LIBRARY FOUNDATIONm WIKI
`
` Digital Library
`
`D
`
`All Content
`
`I!
`
`0 Submissions
`Submission and Review
`Instructions to Authors
`
`LaTeX Packages
`I Publication Forms
`
`I I I
`
`I Regrints
`0 Features
`
`I Sgecial Sections
`Software & Algorithms
`Geophysics Letters
`Section Headings
`Kezw ords
`a General
`I SEG Research Collection
`
`httpinibraryseg.or9’doifabsfl0.11mn.1442787
`
`WesternGeco Ex. 1013, pg. 9
`
`WesternGeco Ex. 1013, pg. 9
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition : GEOPHYSICS: Vol. 55, No. 10 (Society of Exploration Geophysicists)
`
`I Digital Cumulative Index
`I Publications Search
`I SEG Publications
`I Geo h sics Editors
`
`0 The Leading Edge
`The Leading Edge
`
`Close
`0 Find Articles
`I Current Issue
`
`I List ofIssues
`I Search TLE
`I Most Downloaded
`I TLE Di
`ital Edition
`0 Journal Information
`I About TLE
`I Subscri
`tions
`I Permissions
`
`I Advertising
`0 Submissions
`
`IW
`I Editorial Calendar
`I
`
`Copyright Transfer
`I Ethical Guidelines
`
`I Reprints
`0 General
`I SEG Research Collection
`
`I Digital Cumulative Index
`I Publications Search
`I SEG Publications
`I TLE Editorial Board
`
`0
`
`Interpretation
`Interpretation
`Close
`0 Find Articles
`I Accelerated Articles
`I Current Issue
`I List of Issues
`
`I Search Interpretation
`I Most Downloaded
`0 Journal Information
`
`I About Interpretation
`I Subscri
`tions
`I Permissions
`
`I Advertising
`0 Submissions
`Submission and Review
`Instructions to Authors
`Publication Forms
`Ethical Guidelines
`
`Reprints
`
`http://library.seg.org/doi/abs/10.1 190/1.1442787
`
`WesternGeco Ex. 1013, pg. 10
`
`WesternGeco Ex. 1013, pg. 10
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition : GEOPHYSICS: Vol. 55, No. 10 (Society of Exploration Geophysicists)
`
`0 Features
`I S ecial Sections
`
`I Keywords
`0 General
`SEG Research Collection
`
`Digital Cumulative Index
`Publications Search
`SEG Publications
`
`Interpretation Editors
`Editorial Staff
`
`
`
`o SEG eBooks
`
`I Home
`
`I Browse
`
`I Search
`
`I Acguire
`a Buy Print
`Book Mart
`What's New
`
`Shipping Information
`Series Descriptions
`0 Submissions
`
`Propose a Book
`Program Policies
`Instructions
`Ethical Guidelines
`0 General
`I Books Overview
`I SEG Publications
`I Publications Committee
`I Translations Committee
`
`0 Abstracts
`Abstracts
`
`Close
`
`0 Expanded Abstracts
`All Volumes
`Current Year
`Search
`
`I On USB Drive
`
`0 Global Meeting Abstracts
`I Home
`
`I Browse
`
`I Search
`0 General
`
`I Subscriptions
`I Permissions
`
`I Advertising
`0 Resources
`
`http://library.seg.a’g/doi/abs/10.1190/1.1442787
`
`3/8
`
`WesternGeco Ex. 1013, pg. 11
`
`WesternGeco Ex. 1013, pg. 11
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition : GEOPHYSICS: Vol. 55, No. 10 (Society of Exploration Geophysicists)
`
`I SEG Research Collection
`I Di
`ital Cumulative Index
`I Publications Search
`I SEG Publications
`- EEGS Publications
`EEGS
`Close
`
`0 JEEG
`
`I Home
`I Current Issue
`I List ofIssues
`I Search
`I Most Downloaded
`
`0 SAGEEP Proceedings
`I All Volumes
`I Current Volume
`I On Disc
`I Search
`
`0 Publications Information
`I EEGS Research Collection
`I JEEG Information
`I SAGEEP Information
`I Subscri
`tions
`0 EEGS Information
`I EEGS Home
`I FastTimes
`0 Resources
`
`I Digital Cumulative Index
`I Publications Search
`0 ASEG Publications
`ASEG
`Close
`
`0 Exploration Geophysics
`
`I Home
`I Current Issue
`I List ofIssues
`I Search
`I Most Downloaded
`0 Extended Abstracts
`I All Volumes
`
`I Current Volume
`I Search
`I S ecial Publications
`0 Publications Information
`I ASEG Research Collection
`I Ex loration Geo h sics Information
`I Extended Abstracts Information
`I Subscri
`tions
`0 ASEG Information
`I ASEG home
`
`http://library.seg.a’g/doi/abs/10.1190/1.1442787
`
`4/8
`
`WesternGeco Ex. 1013, pg. 12
`
`WesternGeco Ex. 1013, pg. 12
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition : GEOPHYSICS: Vol. 55, No. 10 (Society of Exploration Geophysicists)
`
`I Preview
`0 Resources
`I Di
`ital Cumulative Index
`I Publications Search
`I SEG Publications
`
`Digital Librarv Home >
`GEOPHYSICS >
`
`Volume 55a Issue 10 (October 1990) >
`10.1 190/l.1442787
`
`Article Tools
`
`GE OPHYSIC S
`
`
`Add to my favorites
`Download Citations
`
`Track Citations
`
`< Previous Article
`
`Volume 55, Issue 10 (October 1990)
`
`Recommend &
`Share
`
`0 Abstract
`0 PDF
`
`. C1ted B
`Recommend to Library
`W J. E. Womack, J. R. Cruz, H. K. Rigdon, and G. M. Hoover (1990). ”Encoding
`t: Tace_oo
`techniques for multiple source point seismic data acquisition.” Encoding
`
`wltter .
`techni ues for multi
`le source oint seismic data ac uisition, 55(10), 1389-
`“ N—‘te.1 e
`1396.
`L—DWSRHF
`doi: 10.1190/1.1442787
`L 1gg
`1s
`'-m GEOPHYSICAL STUDIES
`
`Session History
`
`Recently Viewed
`
`o A new look at
`simultaneous
`sources
`0 A new look at
`
`marine
`simultaneous
`sources
`
`Encoding techniques for multiple
`.
`.
`.
`.
`.
`.
`source pomt seismlc data acqu1s1t10n
`
`Article History
`
`Received: 13 January 1989
`Revised: 9 May 1990
`
`. SUMIC:
`
`Publication Data
`
`Multicomponent
`
`sea-bottom seismiclSSN (print): 0016—8033
`surveying in the
`ISSN(on1ine): 1942-2156
`North Sea—Data Publisher: Society of Exploration Geophysicists
`interpretation and CODEN3 gpysa:
`*
`applications
`J. E. Womack , J. R. Cruz , H. K. Rigdoni and G. M. Hooverit
`'
`>z<
`' W School Of Electrical Engineering and Computer Science, University of Oklahoma, 202 West
`reflectlons w1th a pm "1 mm.“ n?! ma 1 o
`http:/Ilibrary.seg.org/doi/abs/10.1190/1.1442787
`
`5/8
`
`WesternGeco Ex. 1013, pg. 13
`
`WesternGeco Ex. 1013, pg. 13
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition: GEOPHYSICS: Vol. 55 No. 10 (Society of Exploration Geophysicists)
`
`—77 ~ ~ uuyu, mu...m, Um , Jui/
`b—tXOt-tomVClOCI
`iPllilfipS Petloleum Company, Bal'tlesville, OK 74004
`transition zone
`
`° W Recent advances in vibrator electronics have made the use of encoded sweeps
`W01 multiple source point data acquisition possible in an operational setting.
`w Alternatives to existing operational multiple source point data acquisition
`
`APPLICATIONS
`.
`.
`.
`.
`.
`II
`techniques, us1ng complementary serles and E-codes, are developed 1n this
`_
`paper. Most existing techniques are, at each source point, a series of linear
`Recently Searched
`sweeps of predetermined polarity that enables the cancellation of the
`contributions from the other source points in processing. The complementary
`series techniques developed here also choose polarities such that the
`o Anywhere:
`contributions from other source points can be cancelled. Pairs of E-codes have
`_gencodin
`l
`.
`.
`.
`.
`techni ues multi
`—q.—p_%een found that produce no crosscorrelatlon, whlch makes 1t poss1ble to use E-
`source pomt
`_
`_
`_
`_
`seismic data
`codes to produce a dual source pomt technlque that 1s fundamentally d1fferent
`
`from the more conventional techniques. Field tests are carried out using E-
`acquisition (std -
`codes in dual source point schemes. Records from the respective source points
`&1
`' W are readily separated from the composite data collected and compared with
`
`l—OOksimultaneous records produced by a linear sweep from a single source point. Harmonic
`
`S_(-_)OUFCCSStd 644 distortion appears to be the major limiting factor; however, record quality
`
`' [_y:—'cAnwhere sum1 indicates that E-codes can be used1n operational multiple source point data
`multicomponentl
`AND [An where. acquisition.
`
`S—]—.eabottom AND Permalink:http.//dx.doi.org/10.1190/1.1442787
`|SArnywhere: seismic
`.-§std 281
`o Anywhere marineeCited by
`pssp reflections
`Woohyun Son, Sukjoon Pyun, Changsoo Shin, Han-Joon Kim. (2014) An
`b—tyottomVCIOCi
`ngorithm adapting encoded simultaneous-source full-waveform inversion to
`J)
`marine—streamer acquisition data. GEOPHYSICS 79:5, R183-R193.
`Online publication date: 1-Sep—2014.
`Abstract | Full Text | PDF (6368 KB) | PDF w/Links (774 KB)
`Jeff Godwin, Paul Sava. (2013) A comparison of shot-encoding schemes for
`wave-equation migration. Geophysical Prospecting
`61: 10.1 1 1 1/gpr.2013.61.issue-sl, 391-408.
`Online publication date: l-Jun—2013.
`CrossRef
`
`J.W. (Tom 1 Thomas, Dana M. Jurick, Dwight Osten. 2012. Vibroseis as an
`impulsive seismic source - 3D field testing Permian Basin Texas. SEG
`Technical Program Expanded Abstracts 2012, 1-5.
`Abstract | PDF 1 1034 KB) | PDF w/Links (665 KB) 1 Supplemental Material
`Ying Ji, Ed Kragh, Phil Christie. 2012. A new simultaneous source separation
`algorithm using frequency-diverse filtering. SEG Technical Program
`Expanded Abstracts 2012, 1-5.
`Abstract | PDF 1997 KB) | PDF w/Links1794 KB)
`Kees Wapenaar, Joost van der Neut, Jan Thorbecke. (2012) Deblending by
`direct inversion. GEOPHYSICS 77 :3, A9—A12.
`
`Online publication date: 1-May-2012.
`Abstract | Full Text | PDF 1 1361 KB!
`
`Gbovega Aveni. Ali Almomin, Dave Nichols. 2012. On the separation of
`http:f/iibrary.seg.org/doi/abs/10.1 190111442737
`
`6/8
`
`WesternGeco Ex. 1013, pg. 14
`
`WesternGeco Ex. 1013, pg. 14
`
`

`

`111250014
`
`Encodi ng techniqus for m ulh‘ ple s ource point 5 eis mic data acquis iii on: G EOP HYS IC 3: Vol. 55, N o. 10 (S ociety of Expl or 311' on G eophys icists)
`
`simultaneous-source data by inversion. SEG Technical Program Expanded
`
`Abstracts 2011, 20-25.
`
`Abstract | PDF {1544 KB: |PDF wainks
`Gboyega Azeni. 2012. Seismic reservoir monitoring with permanent encoded
`seismic arrays. SEG Technical Program Expanded Abstracts 2010, 4221-4226.
`Abstract | PDF (3150 KB} |PDF w/Links
`
`1W. {Tom} Thomas, Bob Chandler Dwight Osten. 2012. Galcode:
`Simultaneous Seismic Sourcing. SEG Technical Program Expanded Abstracts
`2010, 86-90.
`
`Abstract | PDF {1773 KB} |PDF WfLinks | Supplemental Material
`
`Gboyega Azeni, Yaxun Tang, Bindo Bi ondi. 2012. Joint preconditioned least-
`
`squares inversion of simultaneous source time-lapse seismic data sets. SEG
`
`Technical Program Expanded Abstracts 2009, 3914 -3918.
`MIW IW |W
`W 2012. Simultaneous sources: A technology Whose time has
`come SEG Technical Program Expanded Abstracts 2008, 2796-2800.
`AhmlW IW
`My:WWW 2012 Flam —
`A simultaneous source wide azimuth test SEG Technical Program Expanded
`Abstracts 2008, 2821- 2825.
`
`WIWIW
`WW;W 2012 A new look at
`simultaneous sources SEG Technical Program Expanded Abstracts 1998, 133-
`135
`
`WIWIW
`
`SEG and the
`SEG Foundafion
`wish to thank
`
`our all». sponsors
`
`Advertise with SEG
`
`Offices
`Media
`SEG Committees
`Sections & Societies
`
`Membership
`
`Membership News
`Become a Member
`Current Members
`Member Se arch
`
`Events
`
`h‘ltp'M ibl arys e9. orgfdoilabsflfl. 1193114442787
`
`718
`
`WesternGeco Ex. 1013, pg. 15
`
`WesternGeco Ex. 1013, pg. 15
`
`

`

`11/25/2014
`
`Encoding techniques for multiple source point seismic data acquisition : GEOPHYSICS: Vol. 55, No. 10 (Society of Exploration Geophysicists)
`
`Yllllfl BASEME'"
`[8 “I”. [If
`”ARK swans
`'
`
`
`
`. I
`
`Overview
`Calendar
`0 Annual Meeting
`Lectures & Courses
`Past Meetings
`
`0 .
`
`Resources
`
`Publications
`eNews letters
`Book Mat
`Res earch
`
`Education
`
`eLearning
`Lectures & Courses
`
`University & Student Programs
`Youth Education
`Youth Resources
`
`Groups & Communities
`
`0 eCommunities
`0 Students
`
`0 GWB
`
`I SEAlVI
`
`Terms of Use
`
`Imaole Credits
`Refund Policy
`Privacy Notice
`
`Es Hel
`Geo h sics