CGG

AGORA
2D/3D Adaptive Groundroll Attenuation

Release: v5.05
Last updated: January 2015

1. Function
1.1. General
On land, the effect of the near surface is the major cause of poor seismic data quality.
Surface noise, heterogeneity causing scattering, statics, coupling variations, wave-field
attenuation, and anisotropy all degrade the quality of the wavefield recorded at the surface.

Groundroll are surface waves recorded as "pseudo- Raleigh" waves on the geophone
vertical component and are characterized by elliptical particle motion. They are the result of
interfering P and SV waves that travel along/near the ground surface. As they arrive directly
from the source, they are linear at near cable on 2D/3D but appear hyperbolic on broadside
cables for near-offsets. They are characterized by their low velocity, low frequency, and
high amplitude. Groundroll is dispersive and act as guided waves (called sometimes higher
modes), which means that there are, for each frequency, different apparent velocities -
also called phase velocities.

AGORA is a data-driven approach performing a 2D/3D adaptive groundroll and guided

waves attenuation even with an irregular offset distribution.

AGORA allows removing S-waves from 3D VSP. The domain use to perform this option is a
3D data block of a source line 3D VSP (in TWT) where the downgoing P waves have already
been suppressed.

The AGORA process to attenuate the surface waves can be described by four main steps:

1. Extraction of the groundroll characteristics via a frequency-velocity phase

diagram.

2. Wavelet Domain. Wavelet filter banks allow a multi-resolution approach

with a split of the input data in several frequency-wave number sub-panels
using a highly reversible wavelet transform.

3. Modeling in the FX domain of aliased and dispersive surface waves is done

for each sub-panel using the more adapted set of parameters derived from
the data itself via the frequency-phase velocity panel.

4. Back-Scattering in the FX domain is removed via a fan-rejected filter

approach that can be due to aliased groundroll not removed by the
modeling or backscattering generated by the near-surface or buried
heterogeneities.

AGORA attenuates the imprint of the Simultaneous Shooting acquired during a blended
source acquisition in the X-spread or common receiver-shotpoint domain can be described
by two main steps:

1. Iterative Amplitude Threshold in the (x, t) domain. Several parallel trials

are done using a random order of the trace per each macro offset class.
A combined model of anomalous noise is then generated and subtracted
from the input data.

geovation User Guide AGORA 1

CGG AGORA

2. Fan-slope Random Noise Attenuation in the FX domain. Inside a slope-fan

the signal part of the data is predictable, whereas the random noise is not.
For each frequency of the bandpass a spatial predictor operator is build
inside a fan-slope.

AGORA attenuates the S-waves on 3D VSP using a 3D data block from a whole source
line 3D VSP (a mix of a node view- VSP view). The data is already preprocessed with the
suppression of the downgoing P-waves and moving from a one way to a two traveltime.
In this particular case the up-going P-waves have at least positive or flat slope. The 3D
filtering of the S-waves is taking into account this assumption.

A multi-thread approach is available, which allows AGORA processes to be submitted

using several cores per node (see the parameters descriptions and Section 3,
“Recommendations”, p. 15)

geovation User Guide AGORA 2

CGG AGORA

geovation User Guide AGORA 3

CGG AGORA

2. Function Call
2.1. Description
Column Contents
1 *
3-7 AGORA
9-10 First option:

• Blank: processing in 2D
• AZ: azimuth sector option
• XS: cross-spread option
• VS: source line 3D VSP filtering
12-13 Second option:

• Blank
• GW: guided waves option for blank, XS and AZ first option
15-16 Input buffer: Contains prestack shot or receiver gathers with a Y flag
set according to attribute headers SP_NB, RCV_NB, SP_LINE, RCV_LINE
in the blank option or according to the header attribute defining each
different cross-spread in the XS option.
23-24 Output buffer: Contains the processed gathers, with as many traces as
input.
31-80 Parameters

2.2. Parameters common to all options

2.2.1. Mandatory parameters

FX Modeling

FMINd
d = Minimum frequency, in Hz, to process for the FX modeling (integer).

FMAXe
e = Maximum frequency, in Hz, to process for the FX modeling (integer). Reducing FMAX
will reduce run times but may result in poorer groundroll estimation and suppression
during the FX modeling.

VGMINf
f = Minimum expected groundroll velocity (group velocity) in m/s used to compute the
frequency-phase velocity (f,v) panel (integer).

VGMAXg
g = Maximum expected groundroll velocity (group velocity) in m/s used to compute the
frequency-phase velocity (f,v) panel (integer).

VPMINh
h = Minimum expected phase velocity in m/s used to compute the frequency-phase
velocity (f,v) panel (integer).

VPMAXi
i = Maximum expected phase velocity in m/s used to compute the frequency- phase
velocity (f,v) panel (integer).

geovation User Guide AGORA 4

CGG AGORA

LVIj
j = Number of the velocity library used for the FX modeling (integer).

A single library is sufficient if the limit of the library covers the data limit.

Output

Bk
k = Number of the secondary loop for the normal output buffer (integer).

2.2.2. Optional parameters

Data volume definition

DUPLIa
a = Multiplicative factor used to increase memory for duplicate trace management.

Wavelet transform sub-band's splitting

NITERn
n = Level of recursive iteration.

Possible values:

n = 0: no sub-band splitting

n = 1: 4 sub-band splitting

n = 2: 9 sub-band splitting

Default: 1

Marine data

MARINE
Flag to use adapted routines to process marine data.

Processing in feet

FEET
Flag to adapt routines to parametrization in feet.

Auxiliary output

OS1=m
m = Name of the auxiliary output buffer containing the removed part of the input data.

BAn
n = Number of the secondary loop for the auxiliary output buffer (integer).

Static corrections

LSTz
z = Number of the static correction library used internally for the FX modeling when a
static library is applied before AGORA (integer).

Important

AGORA does not apply static shifts on input data. See Section 4,
“Examples”, p. 17.

geovation User Guide AGORA 5

CGG AGORA

or

DBST=xxx
xxx = String (maximum 15 characters) defining the name of the XPS static type dataset
used internally for the FX modeling when a static library is applied before AGORA.

Important

AGORA does not apply static shifts on input data. See Section 4,
“Examples”, p. 17.

DPp
p = Value of an imaginary auxiliary DP which avoids the loss of samples at the beginning
of the traces if the real DP is far below ground level after static application.

Default: 0

Note

This parameter cannot be coded without LST or DBST.

FX modeling

NTq
q = Number of even traces for the modeling (integer).

Default: 30

NUMCURVr
r = Number of hyperbolae events necessary to model the signal part (integer).

Limits: 1 ≤ r ≤ 5 (where 1 is a small number of hyperbolae and 5 is a high number

of hyperbolae)

Default: 2

NUMMODs
s = Number of linear events necessary to model the noise part (integer).

Limits: 1 ≤ s ≤ 5 (where 1 is a small number of linear events and 5 is a high number

of linear events).

Default: 2

AMCUTt
t = Threshold value to perform spatial amplitude editing before the AGORA process
(real). This is similar to a SPASM process with a fixed number of traces and windows
(NT/2 and L200).

The lower the value of AMCUT, the more efficient the edition.

Limits: 1 ≤ t ≤ 1000

No default.

and

SHALLu
u = Time, in ms, that protects the shallow part in case of very weak amplitude. SHALL
avoids the effect of the AMCUT parameter for the samples up to u ms.

It must be coded with AMCUT.

geovation User Guide AGORA 6

CGG AGORA

FCUTf
f = Maximum frequency saved in hertz (real).

By default, f is the nyquist frequency.

Limits: 0 < f ≤ Nyquist frequency

NTAMCUTt
t = Number of even traces for the spatial amplitude editing before the AGORA process
(real).

By default, the number of traces is NT value.

TMODv
v = Threshold value that allows manual tuning of the modeling starting time for
broadside cables.

Limits: -5 ≤ v ≤ 5

Default: 0.5

MAN
If this flag is coded, the filtering applies the parameters defined by the user for the FX
Modeling. By default, the automatic detection of the phase and group velocity is done.

FLEXVELx
x = Percentage of the phase velocity used to control the data above the modeling time.

Limits: 0 ≤ x ≤ 1

Default: 0.75

TOLBFy
y = Strength of the adaptive filtering on the LF part of the groundroll (real).

Limits: 0 ≤ y ≤ 1 (0 is weak, 1 is strong)

Default: 1

Printing

PRINT
Flag to print header information.

In the blank option:

• If ONE=SP_NB, attribute header SP_NB is printed.

• If ONE=SP_LINE, attribute headers SP_NB and SP_LINE are printed.

• If ONE=RCV_NB, attribute header RCV_NB is printed.

• If ONE=RCV_LINE, attribute headers RCV_NB and RCV_LINE are printed.

In the XS option: the value of parameter ONE and successive values of attribute headers
SP_NB and RCV_NB are printed.

In the AZ option: the value of parameter ONE and successive values of attribute headers
SP_NB and RCV_NB are printed.

Taper for the back-scattering

TAPFx
x = This parameter allows modification of the tapering for the frequency (real value).

geovation User Guide AGORA 7

CGG AGORA

Default: 0.1 of FMAX

TAPVy
y = This parameter allows modification of the tapering of the slope (real value).

Default: 0.1 of VMAX

TAPTc
c = This parameter allows modifying the tapering in time between the raw data and the
filtered data referring to the starting time of the modeling (real value).

By default this taper is 0.1 and corresponds to 250 ms.

Value of 1 is 2500 ms.

Limits: 0 ≤ c ≤ 1

NVELNEG
Flag to switch off the computation of the backscattering.

Harsh filtering

STRONGz
z = This parameter allows filtering of the data before back-scattering (real value).

Limits: 1 ≤ z ≤ 1000

No default.

External mute

WMUTEXr
r = Velocity value used to protect the first breaks. The data will be untouched from 0
to the time related to the mute value.

or

LMUs
s = Number of the mute library used to protect the first breaks.

Important

You must specify the mute value of the first and last offset values.

or

DBMU=xxx
xxx = Name of the XPS mute data set.

WTAPEXt
t = Taper value, in ms.

Default: 200

Multi-threading level

The number of cores per node is automatically managed by the system but could also be
coded by the user using:

NPEa
a = Number of cores per node used for an AGORA process.

geovation User Guide AGORA 8

CGG AGORA

See Section 3, “Recommendations”, p. 15 for job submission advice.

2.3. Parameters specific to the blank option (2D mode)

2.3.1. Mandatory parameters
Data volume definition

ONE=Att_a
Att _a = Ordering attribute in the Y direction.

Important
Only attributes SP_NB and RCV_NB are allowed to set the WORDY in AGORA.

In the case of 3D data processed in 2D mode, the Y bit must be set before AGORA
on the SP_NB or RCV_NB with a WORDY coding equal to RCV_LINE (in case of a
SP_NB) or SP_LINE (in case of RCV_NB).

NXb
b = Maximum number of traces in the input gathers with the Y bit flagged in the X
direction (integer).

DXc
c = Average distance between receivers in meters (2D) or in the inline direction (cross-
spread). Real value.

2.3.2. Optional parameters

Back-scattering effect

KHCUTa
a = Percentage of nyquist wave number to preserve (can be higher than 100). The cut-
off in frequency is adjusted to the aliasing limit. Real value.

Default: 100

Broadside cables

BROAD
If this flag is coded and broadside cables are processed in a 2D mode, the source
distance related to the receiver line is taken into account. By default, data is processed
as a pure 2D line where the source and receivers are not shifted.

Marine data

CASC
If this flag is coded, a second processing is performed on the residual part (input data -
processed input data). The processed residual part is then added to the first processed
input data. The flag MARINE must be set.

2.4. Parameters specific to the XS option

2.4.1. Mandatory parameters
Data volume definition

ONE=Att_a
Att _a = Ordering attribute in the Y direction.

geovation User Guide AGORA 9

CGG AGORA

NXb
b = Maximum number of traces in the input gathers with the Y bit flagged in the X
direction (integer).

DXc
c = in the inline direction. Real value.

NYa
a = Maximum number of traces in the input gathers with the Y bit flagged in the crossline
direction (integer).

DYb
b = in the crossline direction. Real value.

2.4.2. Optional parameters

Change order of processed data

REVORDER
When this flag is coded, the order of processed data in the XS option will be receiver
and shot.

The default order is shot and receiver.

Pre-computation of the starting time of the modeling

PERTIMa
a = Strength of the sliding window filtering of the starting time of the modeling. No
default. 0 is weak and 1 is a harsh filtering.

Limits: 0 ≤ a ≤ 1

NOPROTb
b = This parameter allows to restraint or extend the filtering above the starting time
of the modeling.

b = 0: extend

b = 1: restraint

Synthetic data

SYNTH
Process synthetic data without noise.

Back-scattering effect

KHCUTAd
d = Percentage of nyquist wave number to preserve (real value). The cut-off in
frequency is adjusted to the aliasing limit in the inline direction.

Limits: 100 ≤ d ≤ 150

Default: 100

KHCUTBe
e = Percentage of nyquist wave number to preserve (real value). The cut-off in
frequency is adjusted to the aliasing limit in the crossline direction.

Limits: 100 ≤ e ≤ 150

Default: 100

geovation User Guide AGORA 10

CGG AGORA

Acquisition design

ACQa
a = Type of 3D acquisition.

Possible values:

• a = 0: Orthogonal acquisition (90 degrees between source and receiver

lines). This is the default.

• a = 1: Slanted acquisition (α degree between source and receiver

lines). In this case AZSR is mandatory.

• a = 2: Zig-zag acquisition (α or α + 90 between source and receiver

lines). In this case AZSR and ACQZZ are mandatory.

AZSRc
c = Azimuth between the source and the receiver lines in radians, measured
anticlockwise from the source line.

By default, no azimuth is taken into account.

ACQZZ
If this flag is coded, the attribute FLG_ZIGZAG will describe the zig-zag acquisition.

Both configurations (zig and zag) are processed at once if FLG_ZIGZAG is set to 1 for
the zig (smallest angle between source and receiver lines) and was set to 2 for the zag
(biggest angle between the source and receiver line). In this case, parameter AZSR in
the job should be set with the smallest angle.

Filtering in the receiver or shot point domain

RCV
Flag to perform 3D filtering in the common receiver domain.

or

SP
Flag to perform 3D filtering in the shotpoint domain.

Note
If RCV or SP is coded, parameters KEYA and KEYB are mandatory. Moreover, the ONE
parameter should be properly set.

KEYA=Att_f
Att_f = Ordering attribute header in the X direction in the common receiver or shot
domain.

KEYB=Att_g
Att_g = Ordering attribute header in the Y direction in the common receiver or shot
domain.

2.5. Parameters specific to the AZ option

2.5.1. Mandatory parameters
Data volume definition

ONE=Att_a
Att _a = Ordering attribute in the Y direction.

geovation User Guide AGORA 11

CGG AGORA

NXb
b = Maximum number of traces in the input gathers with the Y bit flagged in the X
direction (integer).

DXc
c = in the inline direction. Real value.

NYa
a = Maximum number of traces in the input gathers with the Y bit flagged in the crossline
direction (integer).

DYb
b = in the crossline direction. Real value.

Sector splitting definition

DEGa
a = Degree value to process the data in azimuth sector. 5 is advised for typical 3D
square WAZ.

ALPHAb
b = Weighting parameter for the dispersion computation. A value of 1 is advised to
start then this should be adjusted regarding the result of the modeling. Typical values
vary from 0.5 to 1.5.

Limits: 0 < b < 3

RADOFFa
a = Radius in meters allowing gathering of traces in each azimuth sectors for the 3D
modeling.

2.5.2. Optional parameters

Pre-computation of the starting time of the modeling

PERTIMa
a = Strength of the sliding window filtering of the starting time of the modeling. No
default. 0 is weak and 1 is a harsh filtering.

Limits: 0 ≤ a ≤ 1

NOPROTb
b = This parameter allows to restraint or extend the filtering above the starting time
of the modeling.

b = 0: extend

b = 1: restraint

Synthetic data

SYNTH
Process synthetic data without noise.

Back-scattering effect

KHCUTAd
d = Percentage of nyquist wave number to preserve (can be higher than 100 up to
150). The cut-off in frequency is adjusted to the aliasing limit in the inline direction.
Real value.

geovation User Guide AGORA 12

CGG AGORA

Default: 100

KHCUTBe
e = Percentage of nyquist wave number to preserve (can be higher than 100 up to
150). The cut-off in frequency is adjusted to the aliasing limit in the crossline direction.
Real value.

Default: 100

Acquisition design

ACQa
a = Type of 3D acquisition.

Possible values:

• a = 0: Orthogonal acquisition (90 degrees between source and receiver

lines). This is the default.

• a = 1: Slanted acquisition (α degree between source and receiver

lines). In this case AZSR is mandatory.

• a = 2: Zig-zag acquisition (α or α + 90 between source and receiver

lines). In this case AZSR and ACQZZ are mandatory.

AZSRc
c = Azimuth between the source and the receiver lines in radians, measured
anticlockwise from the source line.

By default, no azimuth is taken into account.

ACQZZ
If this flag is coded, the attribute FLG_ZIGZAG will describe the zig-zag acquisition.

Both configurations (zig and zag) are processed at once if FLG_ZIGZAG is set to 1 for
the zig (smallest angle between source and receiver lines) and was set to 2 for the zag
(biggest angle between the source and receiver line). In this case, parameter AZSR in
the job should be set with the smallest angle.

2.6. Parameters specific to the GW second option

See Example 3.

Parameters BROAD and KHCUT do not need to be coded for option GW. If GW is coded,
BROAD is implicitly activated.

2.6.1. Optional parameters

OFFMINa
a = Minimum offset at which the guided waves are removed (real).

Default: 0 (all offset are processed)

WMUTINb
b = Internal mute based on a percentage of the vgmin value (real).

Limits: 0 ≤ b ≤ 1

By default, no mute is applied.

geovation User Guide AGORA 13

CGG AGORA

GWMUTEc
c = Threshold to compute an automatic internal mute that varies spatially (real). The
MUTE parameter must be coded.

Limits: 0 ≤ c ≤ 3

By default, no automatic mute is applied.

2.7. Parameters specific to the VS option

For this option the filtering is in 3D where the first dimension is the VSP view and the second
is in node view. See Example 6.

2.7.1. Mandatory parameters

Data volume definition

ONE=Att_a
Att _a = Ordering attribute in the Y direction.

NXb
b = Maximum number of traces in the input gathers with the Y bit flagged in the X
direction (integer).

DXc
c = in the inline direction. Real value.

NYa
a = Maximum number of traces in the input gathers with the Y bit flagged in the crossline
direction (integer).

DYb
b = in the crossline direction. Real value.

2.7.2. Optional parameters

UP
The output buffer is only the up-going waves after filtering.

DOWN
The output buffer is only the down-going waves after filtering.

geovation User Guide AGORA 14

CGG AGORA

3. Recommendations
3.1. Flexible trace header attributes: module-specific
information
There is no modification of the attribute values: all input attributes remain unchanged on
output.

3.2. Recommendations
3.2.1. Multi-threading process
Important

The number of cores per nodes is managed by the job manager via adequate
environment variable (ie NODES_PER_JOB).

The parameter NPE must be lower than the value of this variable.

Inform your IT support about this multi-threading process.

Dedicated queues with only one or two open actors per multi-core node should be the safest
way to proceed for the production follow-up.

The run-time performance is directly related to the memory used per parallel AGORA
process versus of the available memory per each node.

An estimation of the memory used per parallel AGORA process is written in the listing:

Following this value, different scenarios can be built:

Example of an octo-core node with 16 GB of available memory.

Open actors Number of

Used memory per // AGORA job
per node cores (NPE)
> 16 GB 1 8
> 8 GB 1 8
> 4 GB and < 8 GB 2 4
< 4 GB 4 2

3.2.2. New
Several AGORA processes can be cascaded, for example, AGORA blank and Guided Waves
(GW) option. See Section 4, “Examples”, p. 17.

For 2D processes, multi-thread is also available; NPE Y bit blocks are processed at once.
See Section 4, “Examples”, p. 17.

3.2.3. Pre-conditioning of the input data

Important

Before running AGORA, spikes, bursts, and noises must be removed.

geovation User Guide AGORA 15

CGG AGORA

Moreover, bad coupling effects between neighboring receivers in a given shot or receiver
also affect the quality of the groundroll attenuation, especially the adaptive process. This
issue can be handled by a FDNAT sequence in the shot or receiver domain before AGORA.

3.2.4. Statics application on the input data

If some static values and DP are applied before AGORA, these parameters should be coded
in AGORA to be able to adjust the FX modeling inside AGORA. No static corrections are
applied in AGORA.

It may be necessary to re-datum the velocity field to take into account the new DP shift
(for example, in the case of huge near surface velocity variation).

3.2.5. Header attribute pre-conditioning

ONE should be properly set.

3.2.6. Output trace: header attributes updated

Header attributes TDNFK_X and TDNFK_Y are used to store respectively the X coordinate
and the Y coordinate of the bin calculated internally by AGORA after orthogonalization.

3.3. Processing sequence

The module processes prestack gathers (shots or receivers). A Y flag should be set
according to attribute headers SP_NB, RCV_NB, SP_LINE for the 2D mode and according to
the header attribute defining each different cross spread for the cross spread mode. The
module outputs as many traces as input. AGORA should be used in a X(YBi) process.

geovation User Guide AGORA 16

CGG AGORA

4. Examples
Example 1. blank option

* LIBRI VI 01 FILE=..
* LIBRI ST 01 FILE=..
* BOUCL 1
* GETRA ++ XXXX
Y=(ATT)
**
** STATIC VALUES APPLIED + DP
**
* HISTA == ++ LST1,DP-500,RL4500
**
** GROUNDROLL ATTENUATION
** HERE 8 CONSECUTIVE SHOTS ARE PROCESSED AT ONCE
**
* AGORA == 03 ONE=ATT,NX240,B3,DX25,NPE8,
NITER1,FMIN3,FMAX30,NT30,
VGMIN100,VGMAX2500,AMCUT2,
VPMIN500,VPMAX3000,LVI01,BROAD,
KHCUT100.0,NUMCURV1,
NUMMOD1,DP-500,LST1,
* BOUCL 3
** STATIC VALUES DEAPPLIED WITH DP-1
* HISTA 03 ++ LST1,CS-1,CP-1,DP500,RL4000,
* SETRA == XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 17

CGG AGORA

Example 2. XS option

* XPSID ID=TEST
* LIBRI VI 01 DBVI= vel1
* BOUCL 1
* GETRA ++ XXXX
Y=(XS_NUMBER)
****
** GROUNDROLL ATTENUATION
**
* AGORA XS == 03 ONE=XS_NUMBER,NX240,NY240,B3,DX25,DY50,
NITER1,FMIN3,FMAX30,NT30,
VGMIN100,VGMAX2500,AMCUT2,
VPMIN500,VPMAX3000,LVI01,
KHCUTA150.0, KHCUTB120.0,
NUMCURV1,NUMMOD1, OS1=04,BA4,
** There is 8 cores/node
NPE8,
**
* BOUCL 3
** Main output
* SETRA 03 XXXX
* ENDLP
* BOUCL 4
** Auxiliary output
* SETRA 04 XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 18

CGG AGORA

Example 3. GW option for cross-spread

* XPSID ID=TEST
* LIBRI VI 01 DBVI= vel1
* BOUCL 1
* GETRA ++ XXXX
Y=XS_NUMBER,
****
** GUIDED WAVES ATTENUATION
**
* AGORA XS GW == 03 ONE=XS_NUMBER,NX240,NY240,B3,
DX25,DY50,
NITER1,FMIN15,FMAX45,NT30,
VGMIN1800,VGMAX2500,OFFMIN400.,
WMUTIN0.25,
VPMIN2000,VPMAX3500,LVI01,
KHCUTA100.0, KHCUTB100.0,GWMUTE2.
NUMCURV1,NUMMOD1,OS1=04,BA4,
** There is 8 cores/node
NPE8,
* BOUCL 3
* SETRA == XXXX
* ENDLP
* BOUCL 4
* SETRA == XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 19

CGG AGORA

Example 4. Cascaded approach with blank and GW option for XS

* XPSID ID=TEST
* LIBRI VI 01 DBVI= vel1
* BOUCL 1
* GETRA XXXX
Y=XS_NB,
****
** GROUNDROLL ATTENUATION
* AGORA XS == 03 ONE=XS_NB,NX240,NY240,B3,DX25,DY50,
NITER1,FMIN2,FMAX25,NT30,
VGMIN10,VGMAX1500,NUMCURV1,NUMMOD1,
VPMIN200,VPMAX2500,LVI01,
KHCUTA100.0, KHCUTB100.0,
** There is 8 cores/node
NPE8,
* ENDLP
* BOUCL 3
****
** GUIDED WAVES ATTENUATION
**
* AGORA XS GW == 04 ONE=XS_NB,NX240,NY240,B4,DX25,DY50,
NITER1,FMIN15,FMAX45,NT30,
VGMIN1800,VGMAX2500,OFFMIN400.,
WMUTIN0.25,
VPMIN2000,VPMAX3500,LVI01,
KHCUTA100.0, KHCUTB100.0,GWMUTE2.
NUMCURV1,NUMMOD1,
** There is 8 cores/node
NPE8,
* BOUCL 4
* SETRA 04 XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 20

CGG AGORA

Example 5. AZ option

* XPSID ID=TEST
* LIBRI VI 01 DBVI= vel1
* BOUCL 1
* GETRA ++ XXXX
Y=XS_NB
****
** GROUNDROLL ATTENUATION
**
* AGORA AZ == 03 ONE=XS_NB,NX240,NY240,B3,DX25,DY50,
NITER1,FMIN3,FMAX30,NT30,
VGMIN100,VGMAX2500,AMCUT2,
VPMIN500,VPMAX3000,LVI01,
KHCUTA120.0, KHCUTB120.0,
NUMCURV1,NUMMOD1, OS1=04,BA4,
** There is 8 cores/node
NPE8,
** SECTOR 5 degrees
DEG5,ALPHA1.,RADOFF1000,

* BOUCL 3
* SETRA 03 XXXX
* ENDLP
* BOUCL 4
* SETRA 04 XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 21

CGG AGORA

Example 6. 3D VSP processing

* BOUCL 1
* GETRA ++ XXXX
Y=VSP_NS,
* AGORA VS == 03 ONE=VSP_NS_LINE,NX1000,NY1000,
B3,DX15,DY7.5,
FMIN1,FMAX65,
NPE8,KHCUT100.0,
VGMIN200,VGMAX1400.VPMIN300,
VPMAX2400,
LVI1,AMCUT1,NVELNEG,
WMUTEX2400,OFFMIN0,MUTE0.0,BROAD,
* BOUCL 3
* SETRA 03 XXXX
* ENDLP
* PROCS X(YB1)

geovation User Guide AGORA 22