Reflexw Manual

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About REFLEXW 3

The processed files of the folder demodata will also be written to the virtualfolder. This is not visible when running the program Reflexw.

It is strongly recommended not to use any protected folder for the data projects.

If you disable the user account control no difference exists to the former Windowsversion. Two different method of disabling the user account control are listedbelow:

Method 1 - Using MSCONFIG

1. Launch MSCONFIG by from the Run menu.2. Click on the Tools tab. Scroll down till you find "Disable UAP" (this shouldprobably change to UAC in next Vista beta builds and in the RTM version). Clickon that line.

3. Press the Launch button.4. A CMD window will open. When the command is done, you can close thewindow.5. Close MSCONFIG. You need to reboot the computer for changes to apply.

About REFLEXW 4

Method 2 - using the user control panel

1. Open Control Panel.2. Under User Account and Family settings

click on “user account”the "Add or remove user account".3. Click on "Turn User Account Control(UAC) on or off" link.

4. In the "Turn on User Account Control(UAC) to make your computer more secure" click to unselect the "Use User

Account Control (UAC) to help protect your computer". Click on the Ok button.

5. You will be prompted to reboot your computer. Do so when ready. In order tore-enable UAC just select the above checkbox and reboot.



User’s guide - import and first display of GPR-data 9

0.3 Import and first display of GPR-data

In the following the import and the first display of GPR-data within REFLEXW aredescribed. The functions are described using a MALA/RAMAC GPR-example file.You only have to change some options for other data types.

0.3.1 Import GPR-data

1. enter the module 2D-dataanalysis

2. enter the import menu

using the optionFile/Open/import. TheREFLEXW-DataImport menuappears (see figure at theright).

3. Make the following inputs:input format: RAMACoutput format: 16 bit integer filename specification: originalname for example; to be

considered: REFLEXW (untilversion 2.5.x) only uses max.8 (16 from version 3)characters for the filename for DOS-compatibility.Choose X or Y asProfileDirection and Y or X as ProfileConstant.Choose if the traceincrement and/or the coordinates shall be read from theoriginal data.

4. Activate the option Convert to Reflex. A fileopen menu appears with thedirectory ASCII under your project directory as the standard import path. Youmay choose an original RAMAC file (RD3 or RAD-file) from this import path or from any other directory. In any case both RAMAC files (RD3 and RAD) must bepresent. After having chosen the wanted RAMAC file the data are converted intothe REFLEXW internal format and stored under the path ROHDATA under your project directory. With the option PrimaryFile activated the imported data areautomatically displayed into the primary window (see figure below).

5. Exit the import menu using the option exit.

User’s guide - import and first display of GPR-data 10

0.3.2 Display the data

1. After having done the import the data are displayed using the standard plotoptions. You may change these plot options using the option Plot/Options.

Activating this option the PlotOptions menu appears (seefigure on the right).

2. The main plot options for GPR-data are:

- Plotmode

- PointmodeScale- EnergyDecay- AmplitudeScale

Plotmode: by default usePointmode for GPR-data.PointmodeScale: XYScaledPlot: the data arecompletely plotted into thecurrent window provided thatthe two scale options XScaleand YScale are set to 1. Theoption may be used for smalldata (few traces) or if you want



U ’ id i ki 21 U ’ id i ki 22



User’s guide - picking 21

6. When saving the picksusing the format ASCII-columsyou must activate the optionxy-coordinates in addition.

7. 12. Now each line of theoutput file contains thefollowing informations: profiledistance profileconstant-start shot-x shot-y receiver-x receiver-y traveltime depthamplitude code

For zero offset data the shot

and the receiver coordinates are the same and you only may consider onecoordinate pair.

User’s guide - picking 22

0.5.1.3 control and output of single picks for several profiles

It is also possible to save the picks of different 2D-profiles into one ASCII-file.

1. For that purpose first you must save the picks of the 2D-profiles into differentReflexw-pickfiles using the pick format Reflex Win.

2. You may control thelocation of the pickswithin the interactivechoice menu - enter for that purposefile/interactive choicewithin the 2D-

datananalysis - theinteractive 2D-line choicemenu opens

3. Choose the wantedfilepath and press showall lines

4. Click on show picksand choose the wanted

pickfiles (multifile choice using the shift or strg key)

5. Picks belonging to the same code are connected if the option interpolation isactivated. If the option use code within the 2D-dataanalysis is activated thelayershow-colors are used for the display of the picks.

6. If the picks are correct you may leave the interactive choice menu and enter the pick save menu in order to save all the picks for the different 2D-lines into onesingle ASCII-file.

7. Within the save pick menu you must choose the “ASCII-colums” pick formatand you have to activate the option “export several existing picks into 1 ASCII-file”.

8. Click on save and choose all wanted ReflexWin formatted pickfiles (multifilechoice using the shift or strg key).

9. Each line of the resulting ASCII-file contains the following values:traveltime depth amplitude x-shot y-shot z-shot x-receiver y-receiver z-receiver code(optional)

Depths and amplitudes are set to zero if the corresponding options depth andamplitudes are deactivated.



User’s guide - seismic reflection data interpretation 41 User’s guide - seismic reflection data interpretation 42



the shots is displayed using the current plot settings. Because of the normallyhuge number of traces and the chosen plotmode (Wigglemode, XYScaledPlot)the screen display resolution may be too small to plot the data correctly (XScaletoo small). In this case choose the Zoom-option in order to only display a smallpart of the data in x-direction.

NOTE: The standard display within the 2D-dataanalysis uses the product of thegiven traceincrement and the current tracenumber for the axis display. Thereforethis display does not represent the correct coordinates for the combined shotdata and you may ignore them. But you don’t have to worry about them becausethe subsequent sorting and stacking is always done based on the traceheader coordinates (see chap. II below). The coordinates of resulting stacked section(see chap. IV) however are displayed correctly within the standard display.

0.8.2 Setting the geometry (done within the module 2D-dataanalysis)

1. activate the option CMP within the 2D-dataanalysis

2. activate the option geometry

If the geometries have been already entered during the data acquisition and

REFLEXW allows to automatically take over these geometries the geometry isshown in a table with shot number, shot position and receiver line position. If thegeometry is okay you may leave the geometry settings by deactivating the optionCMP and go on with chapter III..

If the geometry is not correct you must proceed with the following steps:

3. There are different possibilities to define the geometry. The most convenientway is to use a standard geometry (option moving line and option fixed line) for a selectable number of traces. Apart from the standard geometry it is alsopossible to edit the geometry of single traces (option edit single traces) or to

load the geometry from an ASCII-file (option read from ASCII-file).



5. enter the second filter step using the optionProcessing/FK-filter/FK-spectrum.

6. The FK-filter/FK-spectrum window appears. Enter the following parameters or options:- activate the option

fk filter-lineparts- enter the filterparameter tracenumber (correspondsto the number of traces per shot)- activate the option generate fk-spectrum

7. a new FK-filter/FK-spectrum windowappears. Enter for example the followingparameters or options:

- activate the optionvelocity range- activate the optionbandpass- activate the optionHanning **2- enter 5 for the taper widths- enter the velocity fanfor example:

1.neg.vel. to -2000,2.neg.vel. to -1000000,1.pos.vel. to 1000000 and2.pos.vel. to 2000. Thesevalues may differ significantly from case tocase. The velocity fanshould be set in such a way that all non desired onsets are suppressed.- enter the wanted ProcessingLabel- start the fk-filtering

8. The filtered data have been plotted into the secondary window (depending onthe settings of the scree splitting within the plot option menu). The surface wavesas well as the first arrivals (refracted waves) are quite well suppressed. If theresult is sufficient the pre-processing is finished and you may continue withchapter IV. If not some other filter or editing steps must be performed.

Within this chapter we have discussed one example of a possible pre-processing.It is not possible to give some general rules for the processing because of the

huge different problems involved with the datafiles.In any case a gain recovery (energy normalization) and a suppression of theunwanted onsets must be performed.




0.8.4 velocity analysis and stacking (done within themodule 2D-dataanalysis)

1. load the pre-processed datafile

2. activate the option CMP within the 2D-dataanalysis

3. click on CMP-sorting/stack 4. Choose the sorting option CMP or SHOT

5. choose the first and last CMP (or SHOT) and the increment for which avelocity analysis shall be done (e.g. 10 for the first, 80 for the last and 10 for theincrement in order to do the velocity analysis for 10 different CMP’s).

6. activate the option velocity analysis

7. the mean traceincrement for the ensembles is asked for. This increment is

used for the equidistant display of the CMP or shot-ensembles.

8. The velocity analysis menu opens with the first CMP(shot)-data ensembleloaded. On the left the current layer model is shown (by default one single layer included). On the right the CMP (or Shot) is shown.

9. Activate the option semblance or unnormalized corr. for doing a firstestimation of the velocity model.

10. Enter the velocity range and increment and start the semblance analysis. Thesemblance is shown in an additional window.

11. set the left mouse button at the wanted positions within the semblanceanalysis window in order to create a velocity model. The velocity model on the leftis automatically updated.

12. Activating the option interactive adaptation allows you to refine the model -for a detailed description of the options see online help.

13. Save the model

14. click on Next to proceed with the next CMP (shot).

15. The last velocity model remains and you may refine the model using theinteractive adaptation or may create a completely new model using the



User’s guide - 3D-datainterpretation 59 User’s guide - 3D-datainterpretation 60



time end: specifies the timerange for the 3D-data cube. The time always starts at0.sorting: determines the sorting of the profiles entering the computation of the timeslices. Four different sortings are possible: fileheader coordinates or geophonecoordinates, midpoint coordinates and CMP coordinates (defined within theindividual traceheaders). 4. choose the wanted filepath and activate the option load 2D-files in order tochoose the wanted 2D-files from the openfile dialog (multiple choice using theshift or str-key).

5. Activating the option start starts the generation of the 3D-datafile. The number of datapoints depends on the entered range of the 3D-cube and the raster increments. To ensure, that the resulting 3D-file does not exceed the max. size of 10243 points, the parameters XRasterincrement and YRasterincrement can beenlarged and/or the volume of the data to be considered can be reduced. The file

will be stored under the path rohdata under the current project directory. After having created the file the 3D-data are automatically loaded into the RAM (seealso chap. 0.9.3). The 3D-datafile can be processed within the 2D-dataanalysis(see chap. 0.9.2).

0.9.1.3 resulting REFLEXW 3D-datafile

The resulting 3D-file has the same REFLEXW format like a 2D-datafile and maybe processed within the 2D-dataanalysis module (chap. 0.9.2.) whereby theinterpretation must be done within the 3D-datainterpretation (chap. 0.9.3).

The different 2D-lines are stored sequentially. The distance axis within the 2D-dataanalysis represents the distance sum over all 2D-lines. Because of thenormally huge number of traces and the chosen plotmode (Pointmode,XYScaledPlot) the screen display resolution may be too small to plot the datacorrectly (XScale too small). In this case choose the Zoom-option in order to onlydisplay a small part of the data in x-direction.

To be considered: If only few 2D-lines have been acquired with a large number of traces the resulting 3D-datafile may have many points in one direction and veryfew in the other. In this case it might be better to use the interpolation method for generating a 3D-datafile from REFLEXW formatted 2D-lines (see chap. 0.9.1.2.2)especially if you want to display timeslices. Although it is clear that the resolutionwill not be enhanced the timeslices may appear more reasonable by theaveraging of the interpolation.



User’s guide - modelling/tomography 73

- enter the outputfile name


0.10.4. tomography



p

6. Start the raytracing using the option start

7. the calculated traveltimes are shown in the lower picture in addition. Now youmay check for the mean traveltime difference using the option Analyse/calculate

traveltime differences

8. If the calculated and the observed raveltimes do not match you may makesome changes wthin the model and restart the raytracing in order to get a better match.

0.10.4. tomography

Tomographic methods have been well established for borehole-borehole or borehole-surface measurements whereby the object will be directly transmitted(so called transmission tomography).

In the case of the 2D refraction vertical tomography all sources and receiversare located within one line at the surface. In order to allow for a high datacoverage within the medium vertical velocity gradients should be present and acurved raytracing for the calculation of the traveltimes must be used.

REFLEXW supports a 2D- and 3D-transmission traveltime tomography and a 2Drefraction tomography. For the 2D-tomography both straight and curvedraytracing is supported. For the 3D-tomography only straight raytracing issupported.

Chapter 0.10.4.1 includes the format and the picking of the traveltime data.In chapter 0.10.4.2 the 2D tomographic interpretation of borehole-boreholetransmission tomography is described.In chapter 0.10.4.3 the 2D tomographic interpretation of a refractiontomography is described.

0.10.4.1 picking the traveltime data and description of theformat

Before performing the tomography the traveltime data to be inverted must bepresent.

REFLEXW uses a 2D or 3D ASCII-data format:

2D-data format:travel time, code, transmitter_X, transmitter_Z, receiver_X, receiver_Z F8.2 I8 F8.2 F8.2 F8.2 F8.2 example (2 travel times):

800.00 1 0.00 2.00 100.00 2.00 801.60 1 0.00 2.00 100.00 6.00

3D-data format:travel time, code, transmitter_X, transmitter_Y, transmitter_Z, receiver_X,receiver_Y, receiver_Z F8.2 I8 F8.2 F8.2 F8.2 F8.2 F8.2 F8.2 example (2 travel times): 800.00 1 0.00 2.00 1.00 100.00 2.00 5.00 801.60 1 0.00 2.00 1.00 100.00 6.00 5.00

These data can be created externally or within REFLEXW when picking theoriginal wavedata.




x_traceheadercoordinates and the shot and receiver positions (positions alongth b h l ) itt t th di t If d ti t d th


Layout 2 (identical to example 2 with 3 shots at 20, 25 and 30 m depth).



the borehole) are written to the y-coordinates. If deactivated the y-traceheadercoordinates are used for the offsets and the x-coordinates are usedfor the positions. You may check your geometry using the option file/edittraceheader.It is only possible to redefine the geometry within one step for the same

shot/receiver layout. Therefore if you have two different layouts as describedwithin example 1 and 2 you must redefine the geometry for these two layoutsseparately.

Layout 1 (identical to example 1 with 3 shots at 20, 25 and 30 m depth).

! Select the wanted filepath and open files. Choose all data belonging tolayout 1

! enter the rec.start (5 m) and rec.end (50 m) and the shot pos. (20, 25 and30 m) within the boreholes

! Enter for rec. offs. the position of the borehole containing the receivers (0 m)and for shot offs.the position of the shot borehole (30 m).

! Activate the “option offset -> x” and choose for “update traceheaders”“fileheader” and click on save. Now the fileheaders of the chosen files will beupdates as well as the traceheaders.

! Select the wanted filepath and open files. Choose all data belonging tolayout 2

! enter the rec.start (0 m) and rec.end (20 m) along the surface and for shotpos. the lateral position of the shot borehole (30 m)

! Enter for rec. offs.the depth of surface line relative to the borehole top (e.g.0 if the top of the borehole is 0) and for shot offs.the depths of the shots (20,25 and 30 m).

! Deactivate the option “offset -> x” choose for “update traceheaders”“fileheader” and click on save. Now the fileheaders of the chosen files will beupdates as well as the traceheaders.




The parameters for a borehole/surface configuration (layout 2 of chap. 0.10.4.1.1with 24 receivers) are the following:


0.10.4.1.3 picking the first arrivals



with 24 receivers) are the following:

nr. channels: 24first trace: 73last trace: 144

shot start: 5shot increment: 5shot offset: 30receiver increment: 1receiver offset: 0First receiver: 0last receiver: 23y-direction shots activated

The rays of these twoconfigurations are shown on theright.

After having imported the data and having defined the traceheader geometry thetraveltime data must be picked.For that purpose activate the option pick and pick the data using one of thepicking options. Open the pick save menu using the option save. The save picks

menu opens (see figure on the right). In any case the picks also should be savedusing the Reflex Win format in order to have the possibility to load them again ina later stage.Use the format ASCII-2D tomography or

ASCII-3D tomography in order to generatethe ASCII-file for a subsequenttomography. With the option “exportseveral existing picks into 1 ASCII-file”activated you may export several existingpickfiles into 1 ASCII-file.

The pick-file will have the extension TOMand will be stored under the path ASCIIunder the current projectpath.


0.10.4.2 performing the transmission tomography


- Enter a name for the final model. Please use not the same name as for thestarting model because this may lead to problems



1. First a starting model must be generated (see chap. 0.10.1) or an alreadyexisting model must be loaded using the option file/load model. Normally thestarting model may be a simple homogeneous model whereby the velocity shouldbe within the expected range.

2. Activate the option Tomo

3. The TomographyGroupBoxopens in addition (see figure on theright). Within this group box youhave to enter the necessarytomography parameters.

- Load the data using the option

load data (see also chap.0.10.4.1). If the 3D-data format isused for the 2D-tomography youhave to specify the secondcoordinate (y or z) within theradiobox sec.coord. The firstcoordinate is always x. The thirdcoordinate is neglected. The ASCII-tomography data may be created within themodulesa. 2D-dataanalysis - save picks using the formats ASCII-2D tomography or

ASCII-3D tomographyb. traveltime analysis - option exportto ASCIIc. modelling - export datatraveltimes to ASCII

- Check the geometry of your loaded traveltimedata using theoption show rays.

- Enter the wanted spaceincrement (equal in x- and z-direction). This increment should bewithin the range of the receiver or shot increment.

- Activate the option curved ray if the curved raytracing shall be used. If activated the option start curved ray specifies the iteration step for which thecurved raytracing will be used first. - For a first tomographic result you may use the other default parameters. There

are no general rules for these parameters but you have to adapt the parametersto your data in order to get the best result.

starting model because this may lead to problems.

- Start the tomography. Thetomographic result is storedusing the “normal” REFLEXW

format. You may display theresult within the 2D-dataanalysis.



User’s guide - modelling/tomography 87 User’s guide - modelling/tomography 88

0.11 Use of CMP-analysis for a single or severalindependent CMP files



independent CMP-files

In the following the use of the velocity adaptationfor a single or several indiependent CMP-files is

described.

1. Enter the CMP-module and load the wantedcmp-file using the option file/open. The file isplotted together with a simple one layer startmodel on the left handside. By default thevelocity for the first layer is set to 0.1 m/ns for GPR or 3000 m/s for seismics respectively. Thedefault max. modeldepth is calculated from thisvelocity and the max. time of the loaded cmp-file.

2. activate the options unnormalized cor. or semblance and use for examplethe following input parameters for the min. and max. vel. and thevel.interval. Click on start and onthe right hand side the correlationhistogram is shown. Within thiscorrelation histogram you maychoose the best adaptedvelocities. Click on the chosenvelocity within the correlationhistogram and the current 1D-model will be updated. Choosethe next best velocity for the nextreflection and a second layer willbe created and so on. The solidlines define the layer velocities, the dashed ones the mean (vrms) velocities. Tobe considered: the mean velocities correspond to those velocities which comefrom the interactive velocity adaptation within the 2D-dataanalysis. To beconsidered especially for GPR data: Only the first-breaks yield correct vrms andlayer-velocities. If a later arrival

(e.g. the second or third half-cycle) is used for the analysis toolow vrms velocities result.Especially the semblanceanalysis may lead to these wrongvelocities because the maximumsemblance response normallyrelates to later arrivals 3. After having created all layers

you still can change interactively(option interactive adaptationactive) the layer boundaries


and/or velocities by simply clicking on the boundary and drag it with pressedmouse key. The same is possible for the velocity within the layer (option velocity

User’s guide - 2D-velocity models 90

0.12 Introduction to the use of 2D-velocity modelsfor further processing



activated). A new layer boundary can be inserted (option insert activated) and anexisting one can be removed (option remove activated). The current 1D-modelcan be stored using any filename. The option model pos. defines the position of the 1D-model along the distance axis. This paramter is important for creating a

subsequent 2D-model consisting of different 1D-models.

4. If several CMP’s are present you may do the same procedure for each CMP.Then you may create a 2D-model using the option 2D-model. Click on createand choose the wanted 1D-models. Enter the filename for the 2D-model. This2D-model can be used for a subsequent 2D-migration or depth-conversion(option CMP-analysis within the 2D-velocity model groupbox). If only one CMP ispresent you still must create a 2D-model for the use within the migration or time-depth conversion. In this case you simply choose one 1D-model when creatingthe 2D-model. A laterally homogeneous 2D-model will be created.

for further processing

A 2D-velocity model will be used for different applications:

• migration• time-depth conversion• CMP-stacking• NMO-correction

Depending on your data different methods for creating a 2D-velocity model aresuitable.

A layered model may be useful if distinct reflections are visible whereas a moresmooth velocity model might be a good choice if only diffractions are present. It is

possible to extract the velocity informations from the data to be processed (e.g.ZO data with diffractions for a subsequent migration or single shot data for asubsequent stacking) or from totally different data (e.g. refraction data). Thereforedifferent methods for creating a 2D-velocity field are implemented wihin Reflexw:

• interactive velocity analysis of zero offset data• CMP velocity analyis• layer picking within zero offset data• interactive model generation based on seismic refraction data• tomographic inversion


0.12.1. 2D-model from the interactive diffraction analysis


0.12.2. 2D-model from CMP velocity analysis



ZO (zero offset)-data

Interactive velocity adaptation of diffractions or coredata

2D-rasterfile containing mean velocities by spatial interpolation

single “mean velocity” points

Time-depth conversionMigration

-> single mean velocity points from which a 2D-mean velocity model is created byspatial interpolation

step by step guide:

• load the ZO-profile• activate the option velocity adaptation• choose and adapt the wanted diffractions or use the coredata adaptation• save the adaptations on file• click on 2D and enter a rasterfilename (optional)• activate within the processing migration menu any of the 2D migrations

or the timedepth conversion• choose hyperb.adaptation (creates automatically a 2D-rasterfile) or rasterfile mean if you manually created a rasterfile using the option 2D

• perform the processing - the hyperb.adaptation file or the mean rasterfilewill be queried.

external informations from boreholesSingle CMP’sshot data (prestack)

CMP (1D)-velocity analysis

single 1D-layer models

2D-rasterfile containing mean velocities (vrms) by spatial interpolation

Time-depth conv.CMP-stacking NMO-correction Migration

-> single 1D-layer models from which a 2D layer velocity model is created byspatial interpolation

step by step guide for shot data (for a detailed description of the CMP-geometryand stacking see the seismic reflection guide):

• load the single shot data (all shots must have been stored within onesingle file)

• activate the option CMP and choose the wanted ensembles for the

velocity analysis• enter the velocity analysis and create the 1D-models for the chosenensembles

• enter the 2D-model panel and create the 2D-model (2dm-file). If arasterfilename has been entered this Reflexw rasterfile can be used later for stacking

• close the velocity analysis menu and activate load 2D-model. Activatefor filetype 2D-models if you want to load the created 2D-model (spatialinterpolation will be done automatically). The filetype Reflexw rasterfilemean allows you to load the already rastered mean velocityfile whencreating the 2D-model.

• perform the stacking or the nmo correction


step by step guide for ZO-data and additional single CMP-data

• enter the CMP(1D) velocity analysis menu load the single CMP data


0.12.3. 2D-model from the layershow (picked interfaces)



• enter the CMP(1D)-velocity analysis menu load the single CMP data• create the 1D-model for the choosen CMP and enter the shot and model

position• load the next CMP and create the next 1D-model together with the

correct shot and model position• enter the 2D-model panel and create the 2D-model (2dm-file). If a

rasterfilename has been entered this Reflexw rasterfile can be used later for migration or timedepth conversion

• close the velocity analysis menu and enter the 2D-analysis module• activate within the processing migration menu any of the 2D migrations

or the timedepth conversion• choose CMP-analysis (creates automatically a 2D-rasterfile) or rasterfile

mean for the already rastered mean velocityfile when creating the 2D-model.

• perform the processing - the hyperb.adaptation file or the mean rasterfilewill be queried.

ZO (zero offset)-data

Pick the interfaces and create alayershow

layered 2D-model

2D-rasterfile containing layer velocities by spatial interpolation

Migration Time-depth conversion

-> Reflexw layer rasterfile

step by step guide:

• load the ZO data within the 2D-dataanalysis• activate pick and pick the interfaces and store each interface on a

separate file with the velocity above the interface (layernumber mustincrease with depth)

• pick and save a last horizontal layer at the max. traveltime or a little bit

less by setting one pick at the profilestart and another pick at theprofileend and use the option interpolate (the interface will becontinuous). Use for velocity the velocity of the lowermost layer

• enter the layershow and create the layershow using the pickfiles (optionlayer pick vel. within the velocity choice panel must be chosen).

• click on export and activate the option generate Reflexw rasterfile, clickon start

• close the layershow panel and activate within the processing migrationmenu any of the 2D migrations or the timedepth conversion

• choose rasterfile layer for the already rastered layer velocityfile• perform the processing - the layer rasterfile will be queried. menu


0.12.4. 2D-model from the modelling menu, e.g. fromrefraction data


step by step guide:

• enter the model generation menu



External informationsfrom

1D-models fromCMP-velocity analysis

Seismic refractiondata

Interactive model generation

layered 2D-model - layer boundaries with layervelocitieswhich also may vary laterally

2D-rasterfile containing layer velocities

ZO (zero offset)-datashot data (prestack)

Time-depth conversionCMP-stacking NMO-correction Migration

-> Reflexw layer rasterfile which will be used for a different dataset like a zerooffset file for subsequent processing

• enter the model generation menu• create manually a 2D-velocity depth model or generate the model from

seismic refraction data or from single 1D-models• enter a rasterfilename and activate the option fill

• close the model generation menu and load the different dataset (either ZO-data or single shot data)

single shot data:• load the single shot data and activate the option CMP• choose the wanted ensembles for the stacking• activate load 2D-model - choose for filetype Reflexw rasterfile layer for

the already rastered layer velocityfile• perform the stacking or the nmo correction

zero offset data:• load zero offset data and activate within the processing migration menuany of the 2D migrations or the timedepth conversion

• choose rasterfile layer for the already rastered layer velocityfile• perform the processing - the layer rasterfile will be queried



2D-Data-Analysis 99

print the current data files (see also Print Menu). Depending on the current

settings either only the primary file or the primary and secondary file are

2D-Data-Analysis 100

pick button: enters the Pick MenuItem

t th L Sh M It



settings either only the primary file or the primary and secondary file areprinted based on the current splitting parameters. With the optionshowmarker activated (see PlotOption) the markers are printed in addition.The size of the markers are taken from the size defined within the symbol

font (see FontSettings).

copy to clipboard

enter FileHeader Edit

enter PlotOptions

scroll to the left

stop scrollingscroll to the right

The spin button located beneath the autoscroll options defines a delay factor inorder to slow down the scrolling. Value 0 no delay - value 50 max. delay.

allows to easily switch between pointmode and wigglemode

replot current line with current zoom parameters

resets the x- and y-scale values (zoomvalues) to 1 and replots the current

line

enable magnifying glass function

enable manual zoom - With the option ZOOM an arbitrary area of the data

set can be selected and plotted in full screen size. If the screen is split inorder to show two data sets, this option can be applied to each data set,but not across the separating line of the two data sets. With split screen theZOOM option automatically acts on both data sets.

The area to be enlarged, a rectangle, has to lie within a data set. Pressingthe left mouse button you determine a corner of this rectangle and bymoving the mouse with pressed button the desired area is opened.The zoom range may be changed step by step using the small + or -buttons on the right side. Clicking on the + button increases the zoom by10 %, clicking on the - button decreases the zoom by 10 %, this means thex-y-range to be shown will be larger.The current zoom may be stored using the small "s" button and may berestored using the small "g" button.

enters the velocity adaptation MenuItem

enter the LayerShow MenuItem

CMP button: enters the CMP-processing

AD button: enters the AD-conversion module

act.palette: load the wanted color palette from the stored palettes (see alsoPlotOptions menu).

plotscale: enter multiplication factor for the color-amplitude assignment or enter multiplication factor for the wiggle size.



2D-Dataanalysis, Global MenuItem 109

distance dimension defines the used dimension in x-distance (either METER or FOOT). Depending on this setting the velocity dimension is either m/s (m/ns) or ft/s (ft/ns).use shot for discr : if deactivated the shot numbers are not used for the

2D-Dataanalysis, Plot MenuItem 110

1.3 Plot MenuItem

enter these options either from the main menu or from the main tool bar.



use shot for discr.: if deactivated the shot numbers are not used for thediscrimination of the traveltimelines within the modelling menuuse code for discr.: if activated the codes stored with the picks are used in

addition for the discrimination of the traveltimelines within the modelling or thetraveltime analysis menu. Activate this option for example if different pickfiles for one shotpoint (e.g. refractions and reflections) are loaded or calculated. Then thecode stored with the picks is used in addition to discriminate the traveltimelines(the picks with different codes are not combined using a line).max.diff. for traveltimelines: enter a distance value for the discrimination of thetraveltimes which will be combined with a line within the modelling menu. Theoption might be useful for example if two traveltime branches for one shot havebeen picked but the picks are missing in the neighbourhoud of the shot. Enter avalue smaller than the distance of this gap in order to prevent that his gap willalso be combined by a straight line.

After changing any of these three parameters the traveltimes must be loadedagain in order to take effect.

PlotOptions

Plot: replots current line with current zoom parameters

Reset: resets the x- and y-scale values (zoomvalues) to 1 and replots the currentline

Autoscroll-Right: autoscroll line to right

Autoscroll-Left: autoscroll line to left

Autoscroll-Stop: stop autoscroll

ManualZoom: enable manual zoom.Click on the uppermost left corner of thearea to be zoomed up and drag the mouse to the wanted lowermost right corner with the left mouse button pressed. The two additional speed buttons in the toolbar enable a steplike increase or decrease of the zoom factor.

MagnifyingGlass: enable magnifying glass function. A freely definable data partis continuously magnified within a window when moving the mouse. The zoomfactor can be arbitrarily chosen within the zoom window.



2D-Dataanalysis, Print Menu 157

PrinterSetup: Enter the printer-setup menu.

Partitionscans: enter the max. number contained within one single print bitmap.The program automatically subdivides the printer bitmap based on the enterednumber. If problems occur with the printing (e.g. something is missing) it might behelpful to decrease this number. The number does not restrict the total number of scans to be printed.

2D-Dataanalysis, Print Menu 158

1.8.6 Printing on banner paper

Banner printing (printing on continuous paper) is supported. The followingrestrictions are valid for banner printing:

- no automatic center- no page blocking



Preview: Enter the print preview menu which allows a preview of the size of theprintoutput and to define text boxes (for a detailed description see chap. 1.8.7).

CANCEL: break off printing

PRINT: start printing

p g g

- no print frame- the border in banner direction is always set to 0

- because banner printing is still a page based printing the following problems

may occur when switching to the next page:- axis numbering is not correct- the wiggles may be disturbed at this position



2D-Dataanalysis, 1D-Filter 185

Activating the option sequence proc. additionally open the Sequence Processingmenu. With this menu opened you may easily add the current processing step tothe sequence processing flow which may be applied to a choosable number of lines after.


1.11.1.1 Meanfilter

The filter acts on each trace independently. The filter performs a mean over aselectable number of time sample for each time step.

The filter parameter mean range determines the window width in samples over which an averaging of the amplitudes of a trace is performed. With a windowwidth of 4 samples the mean value of the current, the two preceding and the twofollowing samples of a trace is calculated and assigned to the current sample asa new value If between the current sample and the beginning or the end of a



a new value. If between the current sample and the beginning or the end of atrace lie fewer samples than half of the window width the window width isdecreased on one side.

The effect of this mean value averaging complies with a lowpass filtering in thetime domain, which is the more pronounced the larger the chosen window width.This filter is much faster than an application of a lowpass filter with, e.g. abandpass filter, but not as variable.

1.11.1.2 Medianfilter

The filter acts on each trace independently. The filter performs a median over aselectable number of time sample for each time step.

The filter parameter median range determines the window width in samples over which the median of the amplitudes of a trace is performed. With a window widthof 4 samples the current sample, the two preceding and the two followingsamples of a trace are sorted according to their value. The median of thesesamples, i.e. the third largest or the third smallest value, respectively, is assignedthen to the current sample. If between the current sample and the beginning or the end of a trace lie fewer samples than half of the window width the windowwidth is decreased on one side.

The median filter can be employed for deleting spikes from the data. The lowpass

effect of the median filter is the stronger the larger the selected window width.




1.11.1.15 Shaping

The option allows to convert the characteristic waveform of the profile to a newdesired one.

Both the new desired waveform andthe characteristic input wavelet mustexist within an independent Reflexw

datafile. The two Reflexw datafilesmay contain one or more traces butin an case onl the first trace ill be




in any case only the first trace will betaken as the corresponding newdesired and old input wavelet. Sucha wavelet can be easily extractedfrom any profile using the optionextract wavelet (chap. 1.11.1.16).

After having chosen these desiredand input waveform file the filter

length and the time shift must beentered. By default the filterlengthand the timeshift equal the length of the desired wavelet. The scalingfactor allows to enter amultiplication factor by which the data are multiplied after shapingThe amplitudes of the desired and the characteristic waveform should be in thesame order.The option load wavelets allows to reload the desired and input wavelets.

The correct choice of the filter length may reduce the effect of filter inducedprecursors. The following two pictures (point and wiggle mode) show an example.On the left panel the original data are shown. The middle panel shows the result

using a larger filter length than the length of the desired wavelet and the rightpanel shows the result with a filter length equal to the desired wavelet length.

The shaping filter can be used for example to reduce the length of the waveforms(e.g. due to reverberations).

1.11.1.16 extract wavelet

The option allows to extract a characteristic wavelt from the actual profile.

The desired characteristic wavelet must be defined by the selection of atrace/time given by the filter parameters. The first filter parameter specifies thestart time (start ref.time) and the second one the end time (end ref.time). Thethird parameter gives the start distance range (start ref.distance) and the fourthone the end distance range (end ref.distance). Over the selected traces anautomatic averaging is performed for each selected time value. The selectedtrace/time range can be for example the area of the first arrival.

The option can be used for example for defining the new wanted and the inputwavelet for the shaping filter (chap. 1.11.1.15).



2D-Dataanalysis, StaticCorrection/muting 207

1.11.3 StaticCorrection/muting

The following correction, muting and filter possibilities are included within thestatic correction/muting group:

static correctiondynamic correctionmove starttime

mutingsurgical mutingtime cut


the sequence processing flow which may be applied to a choosable number of lines after.



correct max. phasecorr.max.phase/wrapcorrect picked phasecorrect for 2 layerscorrect 3Dtopography

For some filters available within this group the original trace is shown together

with the currently filtered trace, the spectrum of the original trace and thespectrum of the currently filtered trace. The arrows near the original trace andoriginal spectrum are used to enhance the resolution of the trace and spectrumwindows. The trace or the spectrum is stretched up and down when using thesearrows. The spectrum scale is Hz, if the time scale is in milli-seconds and MHz, if the time scale is in nano-seconds, respectively.In addition to the zooming arrows there exist an equivalent spin button whichallows to move the starting point of the primary and filtered traces as well as of the corresponding spectra.

When activating the options static correction and muting a table appears. With allthese options the inputs may be entered either interactively within the originalprofile or using the table input. The options save and load allow to store thecurrent edit values to an ASCII file and to load the wanted edit values from file,respectively. The trace number for the trace to be displayed in the trace and spectrumwindows can be chosen using the option trace number .

The filter parameters for the individual processing steps are entered within the

filter parameter group. With the option Apply on example trace activated theeffect of the filter parameters is online controlled when changing the parametersby showing both the original and filtered trace. Deactivate this parameter if thiscontrol takes too much computer time.

After having specified the filter parameter, you must enter the processing label(option ProcessingLabel). If already a data set with the same name exists, i.e.also with the same label, it is overwritten after starting the processing.

Activating the option sequence proc. additionally open the Sequence Processingmenu. With this menu opened you may easily add the current processing step to




1.11.3.5 surgical muting

The filter acts on each trace independently. The processing step surgical mutingfacilitates the muting below or above trajectories of a given velocity.

The following possibilities are available:1: Inside mute - edit data between trajectories defined by 1.velocity and2.velocity.

2: Top mute - edit data above mute trajectory defined by 1.velocity.3: Bottom mute - edit data below mute trajectory defined by 1.velocity.4: Around mute - edit data around trajectories defined by 1.velocity and2 velocity


1.11.3.6 Time cut

The filter acts on each trace independently. The processing step time cut offersthe possibility to limit each trace to a predefinable maximum time.

The filter parameter max.time in the given time dimension determines the timeeach trace is limited to. No compression or resorting takes place. Only the timerange is reduced to a preset range.

Use this option for example if the time range was set to a too large range duringthe data acquirement and you want to save disk space and enhance thecomputer speed for the further data processing



2.velocity.

The trajectories are calculated based on the entered velocities and the shot andthe receiver tracehader coordinates.The filter parameter muting window in the given time dimension defines thetimerange for the muting. The option is enabled for top, bottom and around mute.The filter parameter taper window in the given time dimension determines a time

window for a smooth muting. The data within this timewindow above or below themuting curve (dependent from the settings above) are tapered usinga cos-function. A value of 0 means that the data are truncated at the mutingcurve.

computer speed for the further data processing.




2D-Dataanalysis, Declipping/arithmetic functions 222

1.11.4 Declipping/arithmetic functions

The following filter possibilities are included in the declipping/arithmetic functionsgroup:

declipping:declipping/max.valuedeclipping/plateau

declipping/thresholdarithmetic function:additionmultiplication



squarerootnatural logabsoluteexp xset ampl.range to 0

conv. v to epsilon

For all filters available within this group the original trace is shown together withthe currently filtered trace, the spectrum of the original trace and the spectrum of the currently filtered trace.The arrows near the original trace and original spectrum are used to enhance theresolution of the trace and spectrum windows. The trace or the spectrum isstretched up and down when using these arrows. The spectrum scale is Hz, if thetime scale is in milli-seconds and MHz, if the time scale is in nano-seconds,respectively.

In addition to the zooming arrows there exist an equivalent spin button whichallows to move the starting point of the primary and filtered traces as well as of the corresponding spectra. The trace number for the trace to be displayed in the trace and spectrumwindows can be chosen using the option trace number or by clicking in theprimary file using the left mouse button.

The filter parameters for the individual processing steps are entered within thefilter parameter group. With the option Apply on example trace activated theeffect of the filter parameters is online controlled when changing the parametersby showing both the original and filtered trace. Deactivate this parameter if thiscontrol takes too much computer time.

After having specified the filter parameter, you must enter the processing label(option ProcessingLabel). If already a data set with the same name exists, i.e.also with the same label, it is overwritten after starting the processing.

Activating the option sequence proc. additionally open the Sequence Processingmenu. With this menu opened you may easily add the current processing step tothe sequence processing flow which may be applied to a choosable number of lines after.



2D-Dataanalysis, Complex trace-analysis/spectral analysis 229

Four different noise types are supported: white, normal, exponential and self similar. In each case the filter parameter nominal frequency controls thedominant frequency used for the noise type.

2D-Dataanalysis, Trace Interpolation/Resorting 230

1.11.6 Trace Interpolation/Resorting

The following trace interpolation and resorting possibilities are included within thetrace interpolation/resorting group:

markerinterpoltraceincr-resamplingmake equidist.traces

fix profile lengthsplit fileYFlipProfileXFlipProfileresort-traceheader



resort traceheader resort-groupYo-Yo sectionTraceinterpol-3DFileXflip-3DFileshift-3DFile

create 3D-ensembles

When activating the option markerinterpol a table appears. With this option theinputs may be entered either interactively within the original profile or using thetable input. The trace number for the trace to be displayed in the trace and spectrumwindows can be chosen using the option trace number .

The filter parameters for the individual processing steps are entered within the

filter parameter group. With the option Apply on example trace activated theeffect of the filter parameters is online controlled when changing the parametersby showing both the original and filtered trace. Deactivate this parameter if thiscontrol takes too much computer time.

After having specified the filter parameter you must enter the processing label(option ProcessingLabel). If already a data set with the same name exists, i.e.also with the same label, it is overwritten after starting the processing.





2D-Dataanalysis, Trace Interpolation/Resorting 241

1.11.6.14 create 3D-ensembles

This option allows you to subdivide the current profile into different 2D-lineparts.This option allows you for example to redefine the individual ensembles (2D-lines) of a 3D-file (the Ensemble-Nr. within the traceheaders will be updated).

With the suboption automatic activated you only have to enter the number of traces per linepart (filter parameter: nr.of traces). In this case the current profile

is subdivided into equidistant 2D-lineparts each containing the given number of traces.With the suboption manual activated you must manually enter the start positionof each linepart within the table or using the left mouse button within the profile.

2D-Dataanalysis, Edit traces/traceranges 242

1.11.7 Edit traces/traceranges

The following edit possibilities are included within the Edit traces/tracerangesgroup:

removeinterpolateextract

replacereverse polarityset to zeroduplicatemoveinsert profile



insert profileadd profilesubtract profileinsert zero tracesremove zero traces

combine files f.CMPmerge filesmerge in timedir.

When activating the options remove, interpolate, extract, replace, reversepolarity, set to zero, duplicate and move a table appears. With all these optionsthe inputs may be entered either interactively within the original profile or usingthe table input. The trace number for the trace to be displayed in the trace and spectrumwindows can be chosen using the option trace number .

The filter parameters for the individual processing steps are entered within thefilter parameter group. With the option Apply on example trace activated theeffect of the filter parameters is online controlled when changing the parametersby showing both the original and filtered trace. Deactivate this parameter if thiscontrol takes too much computer time.

After having specified the filter parameter, you must enter the processing label(option ProcessingLabel). If already a data set with the same name exists, i.e.

also with the same label, it is overwritten after starting the processing.

Activating the option sequence proc. additionally opens the SequenceProcessing menu. With this menu opened you may easily add the currentprocessing step to the sequence processing flow which may be applied to achoosable number of lines after.




1.11.8 2D-Filter

The following filter possibilities are included in the declipping/arithmetic functionsgroup:

running averagesubtracting averagebackground removal

compressexpandstack tracessubtract tracescompress 3D-fileaverage xy-filter median xy filter





median xy-filter dilation xy-filter erosion xy-filter

For the filter background removal within this group the original trace is showntogether with the currently filtered trace, the spectrum of the original trace and thespectrum of the currently filtered trace. Additionally the reference trace calculatedfrom the filter input parameters is shown.The arrows near the original trace and original spectrum are used to enhance theresolution of the trace and spectrum windows. The trace or the spectrum isstretched up and down when using these arrows. The spectrum scale is Hz, if thetime scale is in milli-seconds and MHz, if the time scale is in nano-seconds,respectively.In addition to the zooming arrows there exist an equivalent spin button whichallows to move the starting point of the primary and filtered traces as well as of

the corresponding spectra.

The trace number for the trace to be displayed in the trace and spectrumwindows can be chosen using the option trace number or by clicking in theprimary file using the left mouse button.

The filter parameters for the individual processing steps are entered within thefilter parameter group. With the option Apply on example trace activated theeffect of the filter parameters is online controlled when changing the parametersby showing both the original and filtered trace. Deactivate this parameter if this

control takes too much computer time.

After having specified the filter parameter you must enter the processing label(option ProcessingLabel). If already a data set with the same name exists, i.e.also with the same label, it is overwritten after starting the processing. After activating the processing label editing a list box appears which shows all labelsalready used for the current line.




CMP velocity analysis 341

vrms: the root mean square velocity is used for calculating the reflectionhyperbola and for determining the layer (interval) velocities from the semblanceanalysis.

mean: the mean velocity (mean for normal incidence) is used for calculating thereflection hyperbola and for determining the layer (interval) velocities from thesemblance analysis.

ray based reflections: option is under View in the main menu. If checked thereflections based on refracted rays are shown in addition to the mean velocity-

based reflections. If the difference between these two reflections is too big, theassumption of the mean velocity is not valid anymore.

StackTrace: option is under View in the main menu. If activated a stack trace onthe basis of the current velocity model is plotted in a new aqua window betweenthe model image and the data image. This option only serves as controlpossibility for the performed velocity analysis. A complete stacking of variousCMPs to a zero-offset profile only can be executed within the module cmp-processing.

NMO corrected ensemble: option is under View in the main menu. If activatedth NMO t d ti b d th t l 1D l it d l i l tt d i

CMP velocity analysis 342



op o s u de e e a e u ac a edthe NMO corrected section based on the actual 1D-velocity model is plotted in anew yellow window next to the stack trace. According to the option stack tracethis option only serves as control possibility for the performed velocity analysis.The NMO corrected section as well as the stack trace will be continuouslyupdated when changing the 1D-model.The horizontal size of the window equals twice the number of traces of thesection (fourth for traces less than 25) unless half of the size of the normaldataimage will be reached.

A tracenormalization and the wiggle mode will always be applied. The following

plotoptions control the display:- ShowWiggle: if active the wiggle will be displayed- filling will be done for positive and negative fill option.



Raytracing 2D 427

The following picture shows the result after 10 iterations using the start modelshown within the upper picture. The true model is underlined using dashed lines.

Raytracing 2D 428

4.7.1.4 3D raytracing

The option 3D-ray allows a 3-dimensional raytracing based on the networkraytracing.The parameters ymin and ymax defines the model range in y-direction. Therasterincrement DeltaX also holds true for the y-direction.The parametera source y and receiv. y define the source and receiver positionsin y-direction. Restriction: the receivers may only be located along one constanty-position.The 3D-model is built up from different 2D-cuts lying within the xz-plane. Theparameter ycoord defines the location of each cut in the y-direction. The option

load allows you to define the wanted 2D-model cuts.

Reflexw Manual

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