Mesa Expert Training Manual Expert

7/21/2019 Mesa Expert Training Manual Expert

http://slidepdf.com/reader/full/mesa-expert-training-manual-expert 1/95

This series of exercises will introduce you to many of theoptions that are available in MESA for the design and QC ofsurveys and subsurface models. t is a good idea to refer to

the MESA user!s manual for more details about the featuresdescribed in these exercises.

• "M" Expert #iles.....................................................$

• Ex %&' (asic MESA Expert )sage...........................*

• Ex %$' (uilding Models..........................................&+

• Ex %* Expert Attributes.........................................$,

• Ex %+ Converted -aves.......................................+

• Ex % Converted -aves /0art 1..........................,*• Ex %, Smart Aperture Tool....................................2&

MESA Expert



GMG Expert Files

The files in the following list are generated by MESA Expert. These files are a combination of

ASC and binary. 3ot all of these files will be found with every database.

File Extension Format Description

4.gmf ASC Model information

4.idd (inary mage ray attribute information

4.ird (inary mage ray information

4.mdd (inary Model attribute information

4.ndd (inary 3ormal ray attribute information

4.nrd (inary 3ormal ray information

4.odb (inary 5ffset ray information

4.rdd (inary 5ffset ray attribute information

4.srd (inary Smart ray information

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EXERCISE #1 -- Basic MESA Expert Usage

This exercise shows the basic se6uence of steps for using MESA Expert. 7ou will be laying out ageometry8 creating a subsurface model8 raytracing the model8 calculating attributes8 and thencreating a synthetic from the raytracing results. This exercise uses a $9 survey and a :pseudo;$9 model as a simple example.

&1 Start MESA or select Ne Data!ase from the File menu. <ay out the receivers andsources using the values shown below. Save this survey as :expert=&;.

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$1 Shoot the survey with a &x$+= template. Create a bin grid with the following parametersand calculate the fold8 offsets8 and a>imuths information.

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*1 Choose "anc$ Mo%el Bil%er from the Expert menu. 0ress the File Ne button tocreate a new model. #ill in the :Model 9efinition; dialog as shown to define your modelspace. Save the model as :expert=&;.

+1 The display shows a map view of the model space. 9raw a cross section on the model thathas a 7 coordinate of = for the start and end of the section. There must be ?ust one crosssection that only has two points and it must extend all of the way across the model space.This will allow you to use the $.9 gridding option.

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1 Switch to &ori'on (ie. 0ress the Ne &ori'on button and draw a flat hori>on at a depthof @+.

,1 9raw four more hori>ons. ori>on$ should go from a depth of @*+ on the left side of themodel to a depth of @+= on the right. ori>on* should go from @+ to @,=. ori>on+

should go from @,B to @2==. ori>on should be flat at @&$=. As you add new hori>ons8you will be prompted to define the position of the hori>on relative to existing hori>ons. fyou define the model from top to bottom8 then select the last item in the order listotherwise8 insert the new hori>on into the proper8 logical place in the se6uence.

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D1 Select )ri%%ing from the Mo%el )ri% button pulldown menu. 7ou have to grid all of thehori>ons to extend them across the *9 model space. Choose *op in the :ori>onSelection for "ridding; list. Select Mo%el Extent in the :"rid Method; list. This sets theTop hori>on to the top of the model space.

21 Select the other five hori>ons in the list and choose +,D from the :"rid Method; list. 0ressthe .Un/Select All &ori'ons button to highlight the five hori>ons and the top hori>on. Thiswill activate the :nc. /dxdy1 edit box. Change the :nc. /dxdy1; field to ,.$. 0ress 0 togrid the model.

B1 Select Displa2 3 4D 5in%o to looF at the results of the gridding.

&=1 Switch to (elocit2 (ie. Choose each layer in the list and set the velocities and density.

"a2er (p (s Densit2

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Top G ori>on& 2== ++= &.D2Bori>on& G ori>on$ $2== &+= $.++2ori>on$ G ori>on* +,== $D= $.2$Bori>on* G ori>on+ +$== $*&= $.D=Bori>on+ G ori>on +2$= $,& $.2=*ori>on G (ottom == *=$ $.2B2

&&1 Save the model and exit Model (uilder.

&$1 Select "oa% Mo%el File from the Expert menu. <oad the :expert=&; model. The modelname will be listed in the <egend after is loaded. 7ou can view the model and the survey inthe *9 -indow. 7ou could also calculate Model Attributes at this point.

&*1 Choose Expert 3 "anc$ En$ance% Ra2tracer to start the raytracer. The model and

survey files will be automatically loaded.

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&+1 Select Ra2tracing 3 6arameteri'e. The model and geometry will already be specified.0ress the Create Ne 9atabase radio button. 0ress the 0tpt Data!ase button andname your raytracing results file :expert=&Henhanced;.

&1 0ress the 6arameteri'e button and choose the ray types to create and which hori>ons touse in the raytracing. Select 0@0 -aves and ead -ave from the 0 -ave options. Selectall five interfaces in the Select nterface/s1 listbox. 0ress 0 and then press the *raceRa2s button to create the ray files. Exit the program after raytracing is completed.

&,1 <oad the expert=&HenhancedHpp.odb ray file into MESA by selecting "oa% 077set Ra2 Filein the Expert menu. The ray file name will be listed in the <egend to show that it has beenloaded.

&D1 Select 4D 5in%o from the Displa2 menu. 0ress the Scene In7ormation button. "o tothe :5ffset Iays; tab and choose all of the hori>ons to display rays from all of the hori>ons."o to the :Sources; tab and select a source in the list to display the rays for that source.The rays are colored by their source G receiver offset.

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&21 Choose Expert Attri!tes from the Expert Attri!tes button pulldown menu. This opensthe Expert Attributes Manager -indow. 0ress the Create 077set Ra2 Attri!tes button.Select the Calclate All Attri!tes radio button and enter a name for the attribute set suchas :hori>on ;. )nchecF the Sa8e CR6 Fol% to Name% Fol% Calclation checFbox andchoose ori>on from the :Target ori>on; list. 0ress 0 to calculate all of the attributesfor ori>on.

&B1 There are eight raytracing attributes that can be displayed in map view. Select the CR6Fol% radio button from the 9isplay listbox. 0ress the Expert Attri!te button in the 9esign

-indow to display the CI0 #old. 7ou can leave the Expert Attributes Manager dialog openwhile you view the attributes in the 9esign -indow. Choose a different radio button in the9isplay listbox to view that attribute.

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$=1 7ou can create synthetic trace gathers based on this rayset. Select )at$er 5in%o fromthe A%8isor menu. Choose Expert S2nt$etic 6arameters from the Displa2 ExpertS2nt$etic )at$er button pulldown menu. Set the 5a8elet *2pe to IicFer. )nchecF all ofthe 3oise Events. )nchecF Top ori>on and ori>on& in the &ori'ons list. Set the *race"engt$.ms/ to &===. 0ress 0 to generate traces from the specified hori>ons.

$&1 Choose the Select Sorce option from the Select Sorces button pulldown menu. The9esign -indow will come to the front. ClicF on a source in the center of the survey. Thetrace gather for that source will be displayed. Apply a gain to the traces by pressing the

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)ain an% Filtering 6arameters button. Select a Mean A)C with an A)C "engt$ of =ms.

$$1 3ext we!ll examine a few bin gathers. Choose Nmeric Entr2 from the Select Bins buttonpulldown menu. Enter &&== for the Starting Bin and &== for the En%ing Bin. Select*race 6rocessing under the Displa2 Expert S2nt$etic )at$er button pulldown menu.

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ChecF the Stretc$ Mte8 Appl2 NM08 and Stac9 Bin )at$ers checFboxes. Set thestretch mute 6ercent to =.$. 0ress 0 to see the stacFed gathers.

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EXERCISE #+ -- Bil%ing Mo%els

This exercise demonstrates how to build depth or time models in Model (uilder. 7ou will useseveral different methods to create hori>ons8 including ASC import8 a bacFground image8 and aSE"7 file. The second model in this exercise is the <aurain model and it uses the parametersand model image presented in <aurain8 I.8 and Jin?e8 J.8 $==&8 0reStacF 9epth Migration and

illumination maps' Expanded Abstracts, SEG 71st

Annual Meeting 8 San Antonio8 M"$.D.

&1 Select "anc$ Mo%el Bil%er from the Expert menu in MESA. Select Ne Mo%el fromthe File menu in Model (uilder. Change the K value from meters to milliseconds. Set aMin L value of @$===8 a min 7 of @&===8 a min K of =8 a Max L of +===8 a Max 7 of +===8and a Max K of +===. 0ress 0 and save the model as :expert=$Htime;.

$1 "o into the Import menu and choose SE): -; "oa%. #or the trace format8 use the file:gatherHwindow.tdf; and for the trace file use the file :+ori>onStacF.sgy;. (oth files areincluded with the example data. Model (uilder automatically creates a cross section usingthe coordinates in the SE"7 header. Switch to &ori'on (ie to see the traces displayedon that cross section. 7ou can use the S$o 6anel E%ges option in the &ori'on (iebutton pulldown menu to toggle the green panel lines on and off.

*1 #or each of the four events in the seismic data8 create a new hori>on by pressing the Ne&ori'on button and defining two endpoints on each side of the section. The first hori>onshould be at &=== ms8 the second hori>on should be at &*, ms8 the third hori>on should

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be at &,,= ms8 and the fourth hori>on goes from $,*, ms to $&+= ms. 7our model shouldnow appear as shown'

+1 "rid the model using Mo%el Extent for the Top hori>on and +,D gridding for all of the other hori>ons with a grid increment of ,=.

1 "o to the (elocit2 (ie and set the velocities for the each layer as shown'

"a2er (p (s Densit2Top G ori>on& $=== &&== $.$ori>on& G ori>on$ $2== &,= $.+Bori>on$ G ori>on* **== &,= $.+Bori>on* G ori>on+ +=== &&== $.$ori>on+ G (ottom === $D= $.2$B

,1 5nce the layer velocities have been defined8 the model must be converted from time todepth. 5nly depth models can be used for raytracing. Simply press the Con8ert to Dept$button to perform the conversion. Model (uilder will prompt you to save the time model

before it is converted to depth. After the conversion finishes8 select Sa8e As from the Filemenu and name the depth model :expert=$Hdepth;.

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D1 Choose File 3 Ne Mo%el and create a model space /units in meters1 with a Min L of =8 aMin 7 of @D=8 a Min K of @===8 a Max L of &8===8 a Max 7 of D=8 and a Max K of =.Save the model as :expert=$Hlaurain;.

21 Choose &ori'on from the Import menu and press the ASCII button in the resulting dialog.<oad the file called :<aurainori>ons.txt; into the mport -indow. n order8 the fourcolumns of this file represent the hori>on name8 the x coordinate8 the y coordinate8 and the> coordinate for the model hori>ons. Set the first data line /line $1 and define the columnsfor importing these four data fields. 0ress the )o button to import the hori>ons. )se a gridinterval of = for the imported hori>ons when you are prompted. 7ou can view the importedhori>ons by selecting 4D 5in%o from the Displa2 menu.

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B1 Switch bacF to the cross section view. )se the Manal Entr2 button and define a singletwo@point cross section line that runs from point /=8=1 to point /&===8=1. Switch to the&ori'on (ie to see the imported hori>ons on this cross section.

&=1 Select Image 3 "oa% from the Import menu. Choose the Fit to Cross Section option andthen load the file :<aurainModel.lyr;. 7ou can now use this image to define the salt lens inthe model.

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&&1 0ress the Ne &ori'on button and give it a name of :Salt Top;. ClicF anywhere on thecross section. This will bring up the :ori>on 5rder; dialog. This dialog is used to place thenew hori>on between two existing hori>ons. This new hori>on needs to be between the:-ater (ottom; and the :Target; hori>ons. Select 5ater Bottom 3 *arget in the list andpress 0.

&$1 ClicF on the leftmost tip of the salt lens to place the first hori>on point. All hori>ons in themodel must extend through the entire model space. ClicF on the far left edge of the crosssection to extend the hori>on in that direction. Ad?ust the points so that the hori>on is as flatas possible and so that it does not intersect the imported :Target; hori>on.

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&*1 )se the right mouse button to >oom in on the salt lens. ClicF points along the top edge ofthe salt lens to define the hori>on around that feature. Extend the hori>on straight acrossfrom the rightmost tip of the salt lens to the right edge of the cross section.

&+1 Create a new hori>on with the name :Salt (ottom;. Again clicF anywhere on the crosssection to bring up the :ori>on 5rder; dialog. Select Salt *op 3 *arget. ClicF on the :SaltTop; hori>on point at the leftmost tip of the salt lens. This linFs the :Salt (ottom; hori>on to

the :Salt Top; hori>on at that point. Model (uilder . 0ress the "e7t button to automaticallylinF the :Salt (ottom; hori>on and the :Salt Top; hori>on to the left of the selected point.

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&1 Koom in on the salt lens again and clicF points along the bottom edge of the salt lens. ClicFon the :Salt Top; point on the rightmost tip of the lens to linF the hori>ons again. 0ress theRig$t button to automatically linF the rest of the hori>on.

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&,1 Select )ri%%ing from the Mo%el )ri% button pulldown menu. Choose *op in the hori>onlist and set its gridding method to Mo%el Extent. Choose the two salt hori>ons and settheir gridding method to +,D. 0ress the .Un/Select All &ori'ons button to select all of thehori>ons8 change the model grid increment to =8 and press 0 to grid the model.

&D1 "o to the (elocit2 (ie and set the velocities for each layer'Top G -ater (ottom' Jp &==-ater (ottom G Salt Top' Jp $+==Salt Top G Salt (ottom' Jp +===Salt (ottom G Target' Jp *===Target G (ottom' Jp *,==

The Js and 9ensity values for each layer will be automatically calculated from the Jp. Save themodel.

Save the model again as expert=$Hlaurain.gmf.

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DO IT YOURSELF MODEL BUILDING

#rom the File menu8 select the Sa8e As option. Save your current model when prompted to doso. Save the new model as :expert=$Hself;.

7ou can use the E%it menu options to move hori>on information between cross sections. f youare in &ori'on view8 you can cut or copy the currently selected hori>on. f you are in CrossSection view8 you can cut or copy all of the hori>ons on the currently selected cross section.

Switch to the Cross Section view on your model and select Cop2 from the E%it menu. 9raw anew cross section8 parallel to the existing cross section8 towards the bottom of the model space.)se 6aste in the E%it menu to put the copied hori>ons on the new cross section. Create anotherparallel cross section towards the top of the model space and paste the hori>ons again.

"o into &ori'on view and edit the hori>ons on the different cross sections. Try adding points8moving points8 deleting points8 and linFing points.

5pen the "ridding dialog and try some of the different gridding methods on your edited model.7ou can view the results by selecting 4D 5in%o from the Displa2 menu.

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EXERCISE #4 -- Expert Attri!tes

This exercise reviews the basic worFflow for Mesa Expert. 7ou will create a simple geometry8 usea model from the previous exercise8 raytrace the model8 and analy>e the calculated attributes.This exercise uses the pseudo *9 laurain model from the previous chapter and one source linefrom a transition@>one style shooting geometry.

&1 Start Mesa and open the Unit *emplate window from the "a2ot menu. Set a grid si>e of $meters when prompted.

$1 <ay out a very small transition >one geometry with two short receiver cables spannedorthogonally by a segment of a source line. #ill out the Template <ayout dialog parametersas shown in the following diagram and press the Exit button.

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*1 The next step is to replicate the unit template to create our source and receiver locations inthe 9esign -indow. 0ress the S$oot 0ptions button in the )nit Template -indow /gunicon1 to bring up the )nit Template Iepeat dialog box. #ill out the parameters as shown inthe following diagram and press 0 to generate the survey. 3ote' Since we are onlygenerating one source line8 the Crossline Spacing is irrelevant.

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+1 (y default8 the )nit Template -indow creates a default $ m by $ m bin grid. 0erform a foldcalculation /Bin Anal2sis-Fol% Calclation1 to verify that you have created a $@fold survey.-e have intentionally made this survey very small in order to 6uicFly complete the raytracingcalculation in the following steps. Save your survey design as :expert=*;.

1 Select Expert-"anc$ En$ance Ra2tracer . -hen the Enhanced Iaytracer program comesup8 select Ra2tracing-6arameteri'e. <oad the :expert=$Hlaurain.gmf; model and the:expert=*.mas; geometry. Select the Create Ne Data!ase radio button. 0ress the 0tptData!ase button and name your raytracing database :expert=*Hall;.

,1 0ress the 6arameteri'e button. #ill out the parameters as shown in the following diagram.

(y default8 all sources will be fired. Select the 6 5a8e radio button and select the 6-6

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5a8es checFbox. Select all four interfaces in the Select Inter7ace.s/ listbox. 0ress 0 when you are finished.

D1 The raytracer is now completely parameteri>ed. 0ress the *race Ra2s button to start theprocess. The main program window will update the status of the raytracing after completingeach source point.

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21 After the raytracing is completed8 select File-Exit and return to Mesa.

B1 n Mesa8 select Expert-"oa% Mo%el File and load :expert=$Hlaurain.gmf;. Select Expert-"oa% 077set Ra2 File and load :expert=*HallHpp.odb;. Select Expert Attri!tes from thepulldown menu of the Expert Attri!tes pushbutton in the 9esign -indow. The Expert

Attributes Manager -indow will appear.

&=1 0ress the Create Mo%el Attri!tes button to open the Model Analysis dialog. This featureallows you to analy>e some characteristics of your model /independent of raytracing1 such asmaximum dip or the maximum bin si>e you can use without spatially aliasing your data. nthis example8 we!ll generate model attributes from two different hori>ons in the model. n theModel Analysis dialog8 set the Attri!te Set Name to :Top of Salt;. Select :Salt Top; from the&ori'on list and press 0,

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&&1 Iepeat this process8 but set the Attri!te Set Name to :Target ori>on; and select :Target;from the &ori'on list. 0ress 0 to complete the calculation. 7ou should now have two setsof model@based attributes listed in the Expert Attributes Manager window.

&$1 Select :Top of Salt; from the list of Calclate% Attri!tes. 0ress the Mo%el Attri!teDispla2 Setp button. The Model Attribute 9isplay 5ptions dialog box allows you to setparameters for viewing dip angles8 bin si>es8 and resolution maps. Select the Maximm Dip radio button and the Dip Angle Map radio button and press 0. 0ress the ExpertAttri!tes button in the 9esign -indow to view the dip angle map for the top of the salt body.

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.

&*1 3ext8 select :Target ori>on; from the list of calculated model attributes in the Expert Attributes Manager -indow. 0ress the Mo%el Attri!te Displa2 Setp button. As before8select the Maximm Dip radio button and the Dip Angle Map radio button and press 0 todisplay the dip angle map for the target hori>on. 3ote the steeply dipping portion of themodel on the west end of the pro?ect.

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3ow8 press the Mo%el Attri!te Displa2 Setp button again and change the display. Select theBin Si'e radio button and set the fre6uency range to 2@2= >.

0ress 0 and you will see a map of the maximum bin si>e without spatial aliasing along thetarget hori>on. n this example8 some of the non@aliased bin si>es are as small as B.,* meters for 2= h>. "iven that our chosen bin si>e for this survey is $ meters8 we can expect some aliasingfor this event unless we either modify our design or change the bin si>e.

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&+1 3ext8 we!ll generate attribute data based on the offset raytracing results. n the Expert Attributes Manager8 press the Create 077set Ra2 Attri!tes button. This opens theCalculate Iaytracing Attributes dialog box. As with the model@based attributes8 raytracingattribute sets are tied to a specific hori>on. f you are only interested in common reflectionpoint /CI01 fold8 select the CR6 Fol% 0nl2 radio button. f you want to calculate the CI0fold plus all the other offset ray attributes8 select the Calclate All Attri!tes radio button.#or this example8 calculate all of the attributes and name the attribute set :5ffset@Target;.5ptionally8 you can also save the CI0 fold calculation to a :named; fold calculation. Thisprovides some additional flexibility for comparing CI0 fold to standard CM0 fold. ChecF theSa8e CR6 Fol% to Name% Fol% Calclation checFbox and give the calculation the name:CI0 #old;. Select :Target; from the *arget &ori'on listbox. 0ress 0 to calculate theattributes for this hori>on.

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&1 The attribute set named :5ffset@Target; now appears in the Expert Attributes Manager list.Select this attribute set from the list. The contents of the Displa2 group box change

depending on which type of attribute set you select. -hen you select an attribute setcalculated from offset raytracing8 eight radio buttons appear. Select the CR6 Fol% radiobutton and maFe sure the Expert Attri!tes button is still pressed in the 9esign -indow.This will produce a map of CI0 fold on the :Target; hori>on in the model.

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&,1 eep the Expert Attributes Manager -indow open and examine the rest of the offsetraytracing attributes by selecting the other radio buttons. The following diagram shows a mapof the two@way travel time for the target hori>on.

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&D1 0ress 0 to close the Expert Attributes Manager. Select )enerate Normal Ra2s from theExpert menu. 3ormal rays are >ero@offset rays that simulate the raypaths after stacFing thetraces in a CM0 bin. Select the S$oot Ra2s 7rom Bin )ri% Centers radio button and namethe output file :expert=*Hnormal;. 0ress 0 to generate the normal rays.

&21 Select )enerate Image Ra2s from the Expert menu. mage rays are >ero@offset rays thatsimulate the raypaths after time migration. Select the S$oot Ra2s 7rom Bin )ri% Centers radio button and name the output file :expert=*Himage;. 0ress 0 to generate the image

rays.

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the migration aperture. #or this example8 the display shows some displacements of N$===mon the western side of the model. Since the bins with these displacements are roughly+===m from the edge of the survey8 our survey extents are probably ade6uate to image thishori>on. f we had large displacement values close to the edge of the model8 we mightconsider extending the extents of our survey.

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$*1 Select :mage@Target; from the list. Select the Displacement radio button and view the resultin the 9esign -indow /maFe sure the Expert Attri!tes button is pressed1. The image raydisplacement is the xy@difference between the reflection point /after time migration1 and theemergence point on the surface. This plot may give some insight into how well time migrationwill position this hori>on. n this example8 there are some bins with relatively largedisplacements on the eastern side of the pro?ect.

$+1 n order to examine the cause of these large displacements in more detail8 open the 4D5in%o from the Displa2 menu. 5pen the Scene In7ormation dialog box and select theImage Ra2s tab. Select :Target; from the listbox to turn on image rays for the target hori>on.-ith the image rays displayed8 it is obvious that the salt body is affecting the path of theimage rays from the target hori>on.

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$1 As a last step8 we will compare the CI0 fold to the CM0 fold. 0erform another CM0 foldcalculation and save the results as a named fold calculation /expert =* G full data1.

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.

$,1 Select Bin Anal2sis-Fol% Compare. Calculate the difference between expert =* full dataand CI0 #old. Store the result in O#old 9ifference;.

$D1 The fold difference between the CM0 and CI0 fold should now be visible in the 9esign-indow. Since some of the difference values will be positive and some will be negative8 itmay be beneficial to use one of the alternate color scales. 0ress the Set 0ptions buttonbelow the color scale in the 9esign -indow to open the Color Scale Settings dialog. )se the

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next and previous buttons to cycle through the standard color scales until you load the red@blue color scale. "rab the :white; slider tab on the color scale and slide it up until is has avalue of >ero. This will set your color scale so that red values are positive and blue valuesare negative.

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$21 #inish this exercise by examining the other model and raytracing attributes available in Mesaexpert.

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EXERCISE #< -- Con8erte% 5a8es

This exercise reviews some of the functionality for modeling the behavior of 0S converted wavesin Mesa 0rofessional and Expert.

&. Create a survey with a single receiver line and a single orthogonal source line using the

following parameters. #irst8 select <ayout@Ieceivers@<inesP(ricFs and lay out a single E-receiver line with &== receivers.

3ext8 select <ayout@Sources@<inesP(ricFs and lay out a single 3S source line with &== sources.

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The simple survey should appear as follows'

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$. Shoot the survey such that every shot fires into all &== receivers. 0ress the Shoot button andcreate a &x&== template. Select the Automatic Template Centering option and maFe sure tounchecF the Template Ioll 5nP5ff checFbox. Jerify that your settings are the same as shownin the following diagram and press the Shoot button.

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7ou will get prompted to set the template roll limits. 0ress the Survey Edges button to Feep thetemplate from rolling off and press the Shoot button. All &== receivers will be active for eachsource points.

Save the database as :singleHcross;.

*. The next part of the exercise will demonstrate how the locations of CM0 midpoints differ from0 to S CC0s /common conversion points1. 0ress the Midpoint Scatter 9isplay toggle buttonto display the CM0 locations. As expected for this survey8 the pattern of CM0 locations willform a s6uare.

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#or the purpose of creating a reference marFer8 select 9isplay@Annotations to open theannotation toolbar. Select the option to Create 0olygon Annotation. Select a line style and a linecolor. n this example8 the user chose to draw a dashed8 red line. ClicF out a s6uare polygonaround the boundary of the CM0 locations. 9ouble clicF on the last vertex to close the polygon.Select 9isplay@Annotations to exit annotation definition mode.

+. Select (in Analysis@Converted -aves from the menu.

ChecF the )se Converted -ave Midpoints checFbox. Set the JpPJs ratio e6ual to $.=. -hile the)se Converted -ave Midpoints checFbox is selected8 all bin attribute calculations in MESA willuse CC0 locations instead of CM0 locations.

Conversion points migrate closer to the receiver locations due to the slower velocity of the Swave on the upgoing travel path. MESA has two different calculations for determining thelocations of 0S conversion points. The traditional method for calculating conversion points usesan asymptotic assumption of a very deep conversion point according to the e6uation'

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CCPxy = SRCxy + (RECxy - SRCxy) / (1 ( Vs / Vp ) )

The second method uses a depth@dependent algorithm for determining the location of the CC0s.nitially8 we are going to use the Asymptotic CC0 calculation8 so select the Asymptotic radiobutton and press 5.

. Change the midpoint scatter display options by selecting the drop down menu from theMidpoint Scatter 9isplay button.

This will open the following dialog box.

Select the CC0 radio button so that the midpoint scatter display will show CC0 locations insteadof CM0 locations and press the 5 button.

,. The 9esign -indow will now show the CC0 scatter using the asymptotic conversion pointassumption for a JpPJs $.=. The following diagram is annotated with arrows to show howthe conversion points have migrated closer to the receiver locations.

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Again8 for the saFe of reference8 select 9isplay@Annotations to open the annotation toolbar.Select a line style and color and draw a box around the extents of the CC0s for a JpPJs $.=.

Select 9isplay@Annotations to close the annotation toolbar.

D. As a final test for the asymptotic CC0 calculation8 select (in Analysis@Converted -aves againand change the JpPJs ratio to +.=. 0ress 5 and the 9esign -indow will update with the

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new locations of the conversion points. As you can see8 the CC0s have migrated evenfurther toward the receiver locations with the increase in JpPJs.

Select 9isplay@Annotations to draw another box around this set of CC0 locations. 7ou may alsowish to add some text annotations to clarify the display as shown in the following diagram.

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2. The next step is this exercise is to demonstrate the difference between the asymptotic anddepth dependent conversion point calculations. Select (in Analysis@Converted -aves again.Set the JpPJs ratio bacF to $.=. This time select the Specify 9epth radio button and set thedepth to &===.=. 0ress 5 when you are finished.

B. The 9esign -indow now shows the locations of the CC0s using the depth@dependentalgorithm.

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Compare the scatter of these conversion points with the outline of the scatter using theasymptotic algorithm and a JpPJs $.=. t should be obvious that for a shallow reflector8 theconversion points are much closer to the receivers using the depth dependent algorithm thanusing the asymptotic algorithm. n fact8 the locations of the conversion points using the depthdependent algorithm are actually closer to the results of the asymptotic algorithm using a JpPJs +.=.

5nce again8 for reference8 open the annotation toolbar /9isplay@Annotations1 and draw a polygonaround the conversion point area. Select 9isplay@Annotations a second time to close theannotation toolbar.

&=. Select (in Analysis@Converted -aves and change the depth of the reflector to *===. <eavethe JpPJs $.= and press 5. The 9esign -indow will update with the new positions of theconversion points.

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3ote that with the deeper reflector8 the positions of the conversion points are now much closer tothe conversion point region using the asymptotic calculation. owever8 if you use theIangeP(earing tool to measure the distance between the corner of the asymptotic region and thecorner of the depth dependent region8 you will find that there is still a difference of about &= feetbetween the locations. This is a large enough difference to affect the fold calculations.

As an exercise8 return to (in Analysis@Converted -aves and change the depth of the reflectoruntil you get a satisfactory match with the asymptotic algorithm. Try the same experiment withusing a JpPJs +.=.

The taFe@away point from this section of the exercise is that both JpPJs and depth play a role inthe location of the conversion points. f your target is sufficiently deep8 either algorithm shouldprovide a satisfactory answer. #or shallow targets8 the depth dependent algorithm is preferable.So why provide both methods in MESA The asymptotic algorithm is more common in theindustry and in some processing systems it may be the only method available for binningconversion points. The depth dependent tool allows you to analy>e the possible ramifications ofthis difference.

&&. Turn off the annotations. Select 9isplay@Annotations to open the annotation toolbar. 0ressthe 9isplay Annotations toggle button to hide the annotations. Select 9isplay@Annotations asecond time to close the toolbar.

&$. n the next phases of this exercise8 we will demonstrate how to directly compare CM0 andCC0 bin attributes. 9efine a bin grid with $ x $ foot bins.

&*. Select (in Analysis@Converted -aves and unchecF the )se Converted -ave MidpointschecFbox. 0ress 5 to close the dialog box.

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&+. Select (in Analysis@#old Calculation. Select the #old8 5ffsets8 and A>imuths radio button.ChecF the 3amed #old Calculation checFbox and name the calculation :p@wave.;

0ress 5F. After the fold calculation completes8 display the fold in the 9esign -indow. 7oushould see a single fold region centered on the intersection of the lines.

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&. Select (in Analysis@Converted -aves. ChecF the )se Converted -ave Midpoints checFbox.Set the JpPJs $.=. Select the Specify 9epth radio button and set the depth to *===.=.0ress 5 when you are finished.

&,. Select (in Analysis@#old Calculation. Select the #old8 5ffsets8 and A>imuths radio button.ChecF the 3amed #old Calculation checFbox and name the calculation :converted@wave.;

0ress 5 when you are finished /you may get prompted to close the bin plotsselect Close1.

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&D. 9isplay the converted wave fold. Since the natural bin si>e for the 0S conversion points isdifferent than the natural bin si>e for the CM0s8 you should see a distribution of bins with>ero8 one8 or two fold.

&2. To directly compare the difference between the CM0 and CC0 fold distribution8 select (in Analysis@#old Compare. n the Compare drop@down list8 select :converted!wave;. n the To

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drop@down list8 select :p@wave;. n the Calc name edit box8 type :fold difference.; 0ress 5when you are finished.

&B. 9isplay the fold difference in the 9esign -indow. 5pen the Color Scale Settings and changethe scale to a 9iscrete Iange color scale with a minimum of @& and a maximum of * /levels1. An example is shown below.

The plot should highlight the coverage differences between CM0 and CC0 /using a depth of*===1 when using the same binning grid. (y comparing the differences in the fold maps8 you may

be able to converge on design parameters /i.e. line spacings1 which produce optimal coverage for both 00 and 0S data.

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$=. f you have the freedom to use a different binning grid for the 0S data8 how do you choosethe appropriate grid si>es #irst8 display the CC0 scatter. MaFe sure that you still have theCC0 radio button selected in the Midpoint Scatter 5ptions /refer bacF to step in thisexercise1. Also8 maFe sure that in (in Analysis@Converted -aves you still have the )seConverted -ave Midpoints checFbox selected8 the JpPJs set to $.=8 and have a Specified

9epth of *===.

$&. Koom in tightly on the CC0 scatter. )se the IangeP(earing tool to measure the inline andcrossline distances between the CC0s. 3ear the intersection of the source and receiver line8the measurement tool shows /roughly1 an inline separation of **.** ft and a crosslineseparation of &,.,, ft.

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Clear all of the IangeP(earing symbols /do this from the drop down menu1 and exitIangeP(earing mode by pressing the toggle button.

$$. 9efine a new bin grid with an inline bin si>e of **.** and a crossline si>e of &,.,,. Centerthe bin grid around the conversion points near the intersection of the source and receiver line.

$*. 0erform a fold calculation. Select #old8 5ffsets8 and A>imuths. 7ou can unchecF the 3amed#old Calculation checFbox and simply store the results as the default calculation. 9isplay theresults in the 9esign -indow.

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As you can see8 the converted wave fold coverage is now much more consistent when using anappropriate bin grid. There are a few stripes of >ero fold in the coverage map since theconversion point spacing is not constant when using the depth dependent algorithm /spacingchanges with increasing offset1. As an exercise8 go bacF to the converted wave options andselect the asymptotic algorithm. Ie@do the fold calculation. 7ou will be able to get a uniformsingle fold map using this algorithm.

$+. Save your database. The :singleHcross; survey will be used in 0art of the converted waveexercise.

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EXERCISE # -- Con8erte% 5a8es .6art II/

This exercise continues with the examination of converted wave tools from Exercise %+.

&. -ith the singleHcross survey already loaded in MESA8 launch Model (uilder from the Expertmenu. 9efine a model space with the following parameters.

$. 0ress the Manual Entry button to define a single cross section /west to east1 across themodel space. Add points with coordinates /@&===8 =1 and /,===8 =1. 3ame the cross section:CrossSection&;.

*. 0ress the ori>on Jiew button so you can begin defining the hori>on layers. -e are going tomaFe a simple model with two dipping hori>ons. 0ress the 3ew ori>on button. )se thedefault name /ori>on&1. ClicF the mouse ?ust outside the left edge of the box at a depthnear @$=== feet. ClicF the mouse ?ust outside the right edge of the box a depth near @&===feet.

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+. 0ress the 3ew ori>on button again. )se the default name /ori>on$1. ClicF the mouse ?ustoutside the left edge of the box at a depth near @+=== feet. ClicF the mouse ?ust outside theright edge of the box a depth near @$=== feet.

. 0ress the Model "rid button and select "ridding from the drop down menu. Select all threehori>ons from the list box /Top8 ori>on&8 ori>on$1. Set the grid increment to =.= /this isthe nc. /dxdy1 edit box1.

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3ow select only the :Top; hori>on from the list. #rom the "rid Method drop down list8 selectModel Extent.

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Select :ori>on&; and :ori>on$; from the list. #rom the "rid Method drop down list8 select $.9.

0ress 5 to grid the model.

,. 0ress the Jelocity Jiew button. 7ou should see a model with two dipping hori>ons butwithout a defined velocity structure.

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Select :Top G ori>on&; from the list box. Enter a Jp +=== ftPs. Enter a Js $=== ftPs. <et therest of the values default.

Select :ori>on& G ori>on$; from the list box. Enter a Jp B=== ftPs. Enter a Js *=== ftPs.<et the rest of the values default.

Select :ori>on$ G (ottom; from the list box. Enter a Jp &$=== ftPs. Enter a Js ,,== ftPs. <etthe rest of the values default.

D. As a final checF8 select 9isplay@*9 -indow to view your model. f the model looFs correct8save the model as :singleHcross; and exit Model (uilder.

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2. <aunch the Enhanced Iaytracer /either directly or from the Expert menu in MESA1. SelectIaytracing@0arameteri>e. <oad the model :singleHcross.gmf;. <oad the geometry:singleHcross.mas; /depending on how you launched the raytracer8 these files may already beloaded1.

0ress the 5utput 9atabase button and name the file :singleHcrossHenhanced;. Select theCreate 3ew 9atabase radio button.

0ress the 0arameteri>e button. Select the 0@0 -aves and 0@SJ -aves checFboxes. MaFesure both hori>ons are selected from the Select nterface/s1 list box. 0ress 5 when you arefinished /refer to the following diagram for all settings1.

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B. The setup dialog box should now report that the pro?ect is :0arameteri>ed for Execution.;0ress the Trace Iays button.

-hen raytracing is completed for all &== sources8 exit the Enhanced Iaytracer.

&=. (efore you can use models or raytracing results in MESA8 the files must be explicitly loaded.Even though the model may already be loaded8 select Expert@<oad Model #ile and select

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:singleHcross.gmf.; -hen the raytracing was performed8 the results for the p@p and p@sraytracing was written into separate files. Select Expert@<oad 5ffset Iay #ile and select:singleHcrossHenhancedHpp.odb.; -e will deal with the p@s data momentarily.

&&. 0ress the Expert Attribute button on the toolbar in the 9esign -indow.

-hen the Expert Attributes Manager window appears8 press the Create 5ffset Iay Attributesbutton. n the Calculate Iaytracing Attributes dialog box8 select the radio button to Calculate All

Attributes. 3ame the attribute set :ppHhori>on&;. ChecF Save CI0 #old to 3amed #oldCalculation and name the calculation :CI0 #old@pp&;. #rom the Target ori>on drop down list8select :ori>on &;. Iefer to the following diagram.

0ress 5 to calculate the attributes using the pp reflections from ori>on &. An attribute setnamed :ppHhori>on&; will appear in the Expert Attributes Manager list box.

&$. 0ress the Create 5ffset Iay Attributes button again. n the Calculate Iaytracing Attributesdialog box8 select the radio button to Calculate All Attributes. 3ame the attribute set:ppHhori>on$;. ChecF Save CI0 #old to 3amed #old Calculation and name the calculation:CI0 #old@pp$;. #rom the Target ori>on drop down list8 select :ori>on $;. Iefer to thefollowing diagram.

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0ress 5 to calculate the attributes using the pp reflections from ori>on $. An attribute setnamed :ppHhori>on$; will appear in the Expert Attributes Manager list.

&*. 0ress the 5 button to close the Expert Attributes Manager window. Select Expert@<oad5ffset Iay #ile from the menu. 5pen the file :singleHcrossHenhancedHps.odb;. This filecontains the results of the converted wave /p@s1 raytracing.

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&+. 5pen the Expert Attributes Manager again. -e are now going to create attribute sets for thefirst and second hori>ons using the converted wave data. 0ress the Create 5ffset Iay

Attributes button. n the Calculate Iaytracing Attributes dialog box8 select the radio button toCalculate All Attributes. 3ame the attribute set :psHhori>on&;. ChecF Save CI0 #old to3amed #old Calculation and name the calculation :CI0 #old@ps&;. #rom the Target ori>ondrop down list8 select :ori>on &;. 0ress 5 to calculate the attributes using the psreflections from ori>on &. An attribute set named :psHhori>on&; will appear in the Expert

Attributes Manager list. Iepeat the process to create ps attributes for ori>on $. Iefer to thefollowing diagrams to get the parameteri>ations correct.

&. There are now four sets of raytracing attributes in the list box. Select :ppHhori>on&;. SelectCI0 #old from the set of radio buttons in the 9isplay group box.

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f the CI0 #old for ori>on & is not already visible in the 9esign -indow8 press the Expert Attributes toggle button on the 9esign -indow toolbar. 7ou should see the CI0 #old map.

As expected8 the reflection points have migrated up@dip for our model and we no longer have asymmetrical8 uniform single@fold s6uare centered on the intersection of the source line andreceiver line.

&,. Select the :ppHhori>on$; from the list box. The display will be updated with the CI0 #oldmap for ori>on $.

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The reflection points have migrated even farther up@dip for the second hori>on.

&D. Select the :psHhori>on&; from the list box. The display will be updated with the CI0 #oldmap for ori>on & using the converted wave raytracing.

3ote that the distribution of conversion points is similar to the distribution using the depthdependent conversion algorithm /exercise +8 step B1. The differences are due to the conversionpoints migrating up@dip and the difference in depth from the west side of the model to the eastside of the model.

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&2. Select the :psHhori>on$; from the list box. The display will be updated with the CI0 #oldmap for ori>on $ using the converted wave raytracing.

&B. TaFe a moment to examine some of the other displays for the four attribute sets. #orexample8 select attribute set :psHhori>on$; and choose Two@way Travel Time. 7ou shouldsee the following display.

3ote' There is one caveat as you examine the attributes for the converted wave raytracing. (othCM0 to CI0 9isplacement and CM0 to CI0 A>imuth show the difference between the CM0location and the conversion point calculated from raytracing. These attributes do not show the

75



difference from the depth dependent /or asymptotic18 flat@Earth conversion point positioncalculated in MESA and conversion point calculated from raytracing. $=. Toggle off the display of the Expert Attributes. Select (in Analysis@#old Selection. n the

dialog box8 you will see a list of all the fold calculations you have saved.

Select :CI0 #old@ps&; from the list and press 5. This will load the fold calculation informationfor the converted wave raytracing /hori>on &1 into the standard fold8 offset8 and a>imuth plots.0ress the toggle button to display #old in the 9esign -indow.

As expected8 this should replicate the CI0 #old map that we saw for ori>on & when viewingattributes through the Expert Attributes Manager.

$&. Select any of the standard bin attribute diagrams for analysis of your converted wave results.#or example8 the following diagram shows the near offset plot based on the converted waveraytracing from ori>on &.

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$$. n the next step in this exercise8 we will view the raypaths in the *9 -indow. Select 9isplay@*9 -indow. 0ress the Scene nformation button in the lower left corner of the *9 -indow.

Select the 5ffset Iays tab and select ori>on$ from the list.

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Select the Sources tab and select source &===& from the top of the list.

7ou should now see the converted wave paths for ori>on $ for this source point. The rays arecolor@coded by offset.

Experiment for a few moments by selecting different source points. 7ou can also return to the5ffset Iays tab and select ori>on &. The list boxes for selecting the source points and hori>onsare multi@select if you wish to display the rays for more than one source or for both hori>onssimultaneously.

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$*. As a final step for this exercise8 we will review creating synthetic traces. Select Advisor@"ather -indow. The "ather 9isplay -indow will open. #rom the drop menu of the 9isplayExpert Synthetic "ather toggle button8 select Expert Synthetic 0arameters.

n the Expert Synthetic 0arameters dialog box8 select a IicFer wavelet from the drop down list of-avelet Types. )nchecF the checFboxes four all types of 3oise Events. MaFe sure that bothori>on& and ori>on$ are selected from the ori>ons list box. Iefer to the follow diagram forthe settings.

$+. Choose Select Source from the drop down menu.

This action will bring the 9esign -indow to the front. Select the northernmost source point in thesurvey by clicFing on it with the mouse. The synthetic gather for this source point will be loaded.

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Since we turned off all of the noise events8 only the converted wave reflections for the twohori>ons appear on the gather.

$. #or more information on creating synthetic shot gathers or creating bin gathers8 refer bacF tostep $= of exercise &.

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EXERCISE #= -- Smart Apertre *ool

This exercise will review the building of models from external gridded surfaces and demonstratehow the Smart Aperture tool can be used to determine the extents of your survey design.

&. <aunch MESA. #rom the Expert Menu8 select Expert@<aunch Model (uilder to start the

model building application /if a prompt comes up asFing you to OSave current changes8;answer O3o.;

$. n Model (uilder8 select #ile@3ew Model. 9imension the model as shown in the followingdiagram. The units should be O#eet!. The model should be a $==== foot s6uare with a depthof *== feet. 0ress 5 when you are finished.

*. -e are going to import hori>ons to maFe the model8 but you still need a single cross section

defined across the model. 0ress Manual Entry and define the endpoints of the cross sectionas /=8&====1 and /$====8&====1.

Accept the default name of OCrossSection&.! The window should looF as shown in the followingdiagram.

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+. Select mport@ori>on from the main menu. This will open the mport ori>on dialog box. -ewill be importing an ASC file containing two gridded hori>ons. 0ress the ASC button.

The ASC mport -indow will appear. /3ote' -e will not discuss the details of importing ASC

files here. Iefer bacF to exercise five of the MESA Training Manual for more information on theoperation of the ASC mport -indow.1

. 5pen the file :sasFHmapleHcreeF.txt.;

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There is one line of header information8 so marF line $ as the first data line for importing. SelectOori>on 3ame! from the list box and highlight columns &@&$. 9efine this field as a OString.!Columns $8 *8 and + in this file are L Coordinate8 7 Coordinate8 and K Coordinate respectively.

9efine each of these fields as O#<5AT.! The maximum width of xy@coordinate column is the value$====.==8 so maFe sure you pad the column width appropriately. The maximum width of the >@coordinate is @*&==.==.

After you have defined the four fields for importing8 press the "5 button. 7ou will be prompted/twice1 for a grid interval. Enter a value of &==.= each time.

,. 7ou should see the following diagram in the ori>on Jiew.

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Select "ridding from the drop down menu of the Model "rid button. n the "ridding dialog box8select the OTop! hori>on. Select Model Extent from the "rid Method drop down list and press 5.

Select "ridding from the drop down menu of the Model "rid button a second time. n the"ridding dialog box8 select both O-hiteHShale! and OMedicineHat! from the hori>on list. Select

Iesample from the "rid Method drop down list and press 5.

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D. 0ress the Jelocity Jiew button to complete the model. Enter the following p@wave velocitiesand let the rest of the parameters default'

Top@-hite Shale' +== ftPsec-hite Shale@Medicine at' D== ftPsecMedicine at@(ottom' B=== ftPsec

2. Save the model as :sasFHmapleHcreeF.gmf;. Select 9isplay@*9 -indow to view your model.

Exit Model builder and return to MESA.

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B. #rom the Expert Menu in MESA8 select Expert@<oad Model #ile. 5pen:sasFHmapleHcreeF.gmf;. #rom the drop down menu of the contour display toggle button8select 9isplay C7I from Model.

This interface allows you to select a hori>on from your model and display it as a contour map inthe 9esign -indow. Select OMedicineHat! from the list box and press 5.

The contour map will now display in the 9esign -indow /press the full un>oom button to refreshthe display1. "o bacF to the drop down menu for the contour display toggle button and select

5ptions. Set the Start Elevation to @*=== and press 5.

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&=. The Smart Aperture tool is used to shoot a cone of rays from a point on your model to thesurface. This exploding@reflector raytracing can be used to determine the migration aperturere6uired for your survey to image your target. Select Expert@Smart Aperture Tool from themain menu. A toolbar will be added to bottom of the 9esign -indow.

&&. The important first step in using the Smart Aperture tool is to choose the correct hori>on fromwhich to shoot the rays. The contour map being displayed is ?ust for referenceit has nofunctional tie to the Smart Aperture tool whatsoever. f you are using the contour map forreference8 maFe sure you are currently displaying the proper hori>on. n this case8 we aredisplaying the MedicineHat hori>on from the model. Select OMedicineHat! from the hori>onlist on the Smart Aperture toolbar as well.

The standard rule of thumb for migration aperture is to capture *= degree rays from thereflector. This is the default setting in MESA. 0ress the 5ptions button on the toolbar tobring up the following dialog box.

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The Smart Aperture raytracer shoots a cone of rays from each point you select on thesubsurface hori>on. f you wish to shoot with an angle other than *= degrees8 change thesetting for Maximum ncidence Angle. (y default8 the a>imuthal angle between rays in thecone is $ degrees8 which produces &2= rays per target. t is rare that you will ever need tochange these default values. 0ress 5 to close the dialog.

&$. Koom in slightly on the primary structure on the map. 0ress the Add 0oint Target button.-hen you clicF on a point on the map8 the local dip is calculated. A cone of rays with anincidence angle of *= degrees on the dipping hori>on is shot to the surface. Iefer to thefollowing diagram.

#or each target you select8 a dot displays the location of the target and an oval is drawn aroundthe surface emergence points of the &2= rays traced. The oval represents the migration aperturere6uired to properly image the selected point. f you select a location on the model with little to nodip8 the emergence points will form a circle centered on the target. f you select a location on a

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steeply dipping flanF of a structure8 the emergence points will be sFewed relative to the targetlocation. &*. f you wish to see the full@fold area re6uired to properly migrate all of the target locations you

have selected8 press the Create Aperture ull button.

A convex hull encompassing all of the emergence points will be drawn.

0ress the Clear button to remove all of the targets and the aperture hull.

&+. nstead of defining individual target points for shooting rays8 a more common use of theSmart Aperture tool is to define a target region. n this example8 the ob?ective of the seismicsurvey is to image the 3- flanF of the prominent structure. 0ress the Add 0olygonal Targetbutton. ClicF out a polygon that follows the /@$$==1 foot contour line as show in the followingdiagram. A point target will be created at each grid node along the perimeter of the polygon.

A cone of rays will be shot from each of these targets and an aperture hull will be created thatencompasses the emergence points of all the rays. The area of this hull represents the full@fold area your survey will need to properly image this target.

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&. 0ress the Save to Exclusion file button. Select the 0olygonal Target Iegions checFbox.Select the Save to External Exclusion #ile radio button. 0ress the #ile button and name thefile OsasFHmapleHcreeF.xcl!.

&,. 0ress the Save Smart Iays button. Save the rays to a file named OsasFHmapleHcreeF.srd!.Close the Smart Aperture tool by selecting Expert@Smart Aperture Tool from the main menu.

&D. 5pen the exclusion toolbar by selecting Edit Exclusions from the drop down menu of theExclusion Kone display toggle button. 0ress the Iead Exclusion #ile button.

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5pen OsasFHmapleHcreeF.xcl!. 7ou should see the smart aperture polygon in the list box. 0ress5.

Select Edit Exclusions from the drop down menu to close the exclusion editing toolbar.

&2. The last step in the exercise is to create a survey which properly fills the full@fold region forimaging the ob?ective. Select <ayout@)nit Template. Set a grid si>e of $.= feet. Create aunit template using the parameters in the following diagram.

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0ress the Shoot button. The )nit Template has a feature for filling regions with sources andreceivers. Select the #ill 0olygon radio button. (y default8 the <ayer should be set to Smart Apt GSelection 0olygon and the Kone should be set to 0olygon &. n the Clipping group box8 selectClip #old to (ounds. Also8 select the )se #ull Template checFbox. Iefer to the following diagramfor the settings.

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0ress 5. This will create a survey that fills the smart aperture polygon with full@fold with theappropriate taper >one.

&B. Calculate fold for the survey and display the results. The following diagram shows that thesmart aperture region is filled with +2 fold.

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Save the survey as :sasFHmapleHcreeF;.

$=. 7ou can view Smart Aperture raypaths in the *9 -indow. Select Expert@<oad Smart ApertureIay #ile. 5pen OsasFHmapleHcreeF.srd!. Select 9isplay@*9 -indow. 0ress the Scenenformation button. Select the Smart Iays tab. Select OMedicineHat! from the list box andpress 5.

The cone of rays from each of the perimeter target points will be displayed.

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Mesa Expert Training Manual Expert