Chapter 13 - Vertical Layering

3D Geological Modeling

Chapter 13 – Vertical Layering

Make Horizons The vertical layering process layering process consists of 4 steps: 1. Make Horizons: Insert the inpt srfaces into the 3D Grid. The inpts can !e srfaces fro" seis"ic or #ell tops$ line interpretations fro" seis"ic$ or any other point or line data de%ning the srface. &. Depth Conversion: If the inserted hori'ons and falts are !ilt in ti"e$ the grid "st !e depth con(erted. This process is s)ipped if the falts and inpt hori'ons are already in depth. 3. Make Zones: *dditional hori'ons are inserted into the 3D Grid !y stac)ing isochors p or do#n fro" the pre(iosly inpt hori'ons. 4. Make Layers: The %nal step is to "a)e "a)e the %ne+scale layering$ necessary for property "odeling. These layers de%ne the top and !ase of the cells of the 3D Grid. The %nal step in strctral "odeling is to insert the stratigraphic hori'ons into the pillar grid$ honoring the grid incre"ent and the falts$ de%ned in the pre(ios steps. The reslt after the ,illar ,illar Gridding process as a 3D grid consisting of a set of pillars connecting the -ase$ Mid and Top Top )eletons. *ll the falts to !e incorporated into the "odel ha(e !een de%ned$ and the pillars ha(e !een placed along and !et#een the falts. /or the falted areas$ the hori'ons are !lan)ed 0deleted in a ser gi(en area arond the falts and an e2trapolation is perfor"ed to stretch the srface !ac) onto the falt plane. This #ill ensre that rollo(ers or pll+ps near falts are eli"inated and a high ality layering of the 3D grid is preser(ed. It shold !e noted that the s)eleton grids are "odi%ed if the top+ and5or !ase+ of the inpt data e2tend a!o(e or !elo# the Top+ and5or -ase+ hape ,oints respecti(ely. The 6ey ,illars shold e2tend a!o(e top hori'on and !elo# !ase hori'on to a(oid negati(e (ol"es in the 3D grid hence an e2trapolation is perfor"ed. 1



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Summary of the Process: • • • • •

*ppend ite" in ta!le$ 7se "ltiple drop$ elect inpt data$ Drop sing !le arro#$ De%ne type.

How to create horizons 1. Go to to Structural Modelin ite" in the Processes Pane! &. Do!le Do!le clic) clic) on the the Make Horizons process! The process dialog for Ma)e 8ori'ons #ill pop p called Make Horizons with "#op #ar$ert Model%&D 'rid( as sho#n !y /ig. 13.1. 3. elec electt the the Horizons ta! as it contains the pri"ary controls for "a)ing hori'ons$

)i! *&!*: Ma)e 8ori'ons #ith (#op #ar$ert Model%&D 'rid9 dialog !o2

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4. 7se the +ppend num$er of items in ta$le and specify ho# "any hori'ons to !e inserted as sho#n in /ig. 13.&.

)i! *&!,: The *ppend n"!er of ite"s in the ta!le tool tip . In this case$ insert 4 hori'ons as sho#n in the ne2t dialog !o2$

)i!*&!&: ;"!er of hori'ons dialog

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<. elect the data to se to create the hori'on 0rfaces data$

)i! *&!-: Ma)e hori'ons #ith Top Tar!ert Model53D grid

=. Ma)e sre yor inpt hori'ons are sorted in the correct stratigraphic order in the .nput Pane respecti(ely / 0ase cretaceous$ #op #ar$ert$ #op 1ess$ #op 2tive >. -y highlighting this %le9s na"e 0"a)e !old in the .nput Pane and then Clic) on the !le arro# to the left of the .nput 3* col"n$ and chec) that the na"e of the acti(e data o!?ect is inserted into the input %eld$ see /ig. 13.. @. Ae"e"!er to insert the correct data o!?ect acti(e and the na"e of the hori'on is set eal to the na"e of the inserted data o!?ect. The ser is free to change this na"e. 1B. ,ress +pply. *s sho#n in /ig.13.<.

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)i! *&!4: The correct stratigraphic seence displayed in the input 3* %eld

)i! *&!5: The correct stratigraphic seence

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11. Ma)e sre that the Multiple drop9 icon toggled on$ this allo#s yo to drop a range of data !y only selecting the %rst in a arro#$ as sho#n !y /ig. 13.=. *,! ,ress +pply and 678

)i! *&!9: Mltiple drops in the ta!le !tton clic)ed 13. -y clic)ing 67 the 8ori'ons #ill !e generated. ee that the 8ori'ons folder in the Models Pane no# has the ne# hori'ons inserted. 14. De%ne the hori'on9s geological character 0stratigraphy$ !y clic)ing on the Horizon #ype col"n for specify hori'on. 1. et 0ase Cretaceous to !e erosional and the other srfaces to !e conforma$le$ *5! ,ress +pply and 678 see /ig. 13.>. 1=. -y clic)ing 67 the 8ori'ons #ill !e generated. ee that the Horizons folder in the Models Pane no# has the ne# hori'ons inserted$

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)i! *&!: 8ori'ons displayed in a 3D #indo# #ith their dges

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Depth Conversion If yor 3D grid #ith inserted hori'ons and falts is in ti"e$ yo need to depth con(ert it to get it into the depth do"ain. The depth con(ersion is a (ertical process$ !eginning fro" a D*T7M and progressing do#n#ards$ 8EAIFE; !y 8EAIFE; and ;ED !y ;ED. This con(ersion is applied for each node in the 3D grid. ach node corresponds #ith the intersection of one srface #ith one pillar. The last step after the con(ersion of the hori'ons is the reconstrction of the pillar geo"etry$ falted or non+ falted. The ser is free to force the progra" to follo# the shape gi(en to the pillar dring the falt "odeling 0Vertical$ Linear$ Listric$ and Cr(ed. The nodes are "o(ed hori'ontally to reconstrct the initial shape of the pillars .

)i! *&!;: Depth Con(ersion ettings

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D+#
.nsertin horizons Hhen yo open the Depth Con(ersion process$ all the hori'ons fro" the 3D grid #ill ha(e !een inserted into the ta!le. If yo #ant to se any other srface as inpt$ then yo insert it into the ta!le sing the icons. ;ote that the Ti"e 8ori'ons "st !e the hori'ons that e2ist in the 3D grid$ not the srfaces fro" the ,etrel 2plorer9s Inpt #indo# 02ception is of corse srfaces that do not e2ist in the 3D grid$ li)e the ea!ed in the e2a"ple a!o(e.

=elocity /or (elocity yo can either se a constant (elocity 0VJVE or a linear e2pression for (elocity 0VJVEK)F. /rther$ VE can either !e a constant (ale or gi(en !y a srface. The ) is a constant or a srface. ince F is negati(e !elo# ML ) is a negati(e (ale.

>ell +d?ustment If yo #ant to ad?st the depth con(erted hori'ons to #ell tops$ yo "st enter the #ell tops nder the Depth Hell Tops ta!$ specify the a(eraging "ethod$ and$ if yo #ant a report$ do this nder the Hells ta!. ;ote that yo can specify #hich #ells to !e sed for conditioning #hen

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doing the depth con(ersion nder the Hell Tops preadsheet.

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Make Zones The Ma)e Fones process is the ne2t step in de%ning the (ertical resoltion of the 3D grid. The process creates 'ones !et#een each hori'on. Fones can !e added to the "odel !y introdcing thic)ness data in the for" of isochores$ constant thic)ness and percentages. Hell points can also !e sed to tie top strctres to the #ell pic)s. This process step "ay !e s)ipped #hen no 'onation is gi(en.

How to create zones 1. Go to Structural Modelin ite" in the Processes Pane$ &. Do!le clic) on the Make Zones process. * #indo# pop p called Ma)e Fones #ith #op #ar$ert%&D 'rid9 as sho#n !y /ig. 13.1B$

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)i! *&!*@: Ma)e Fones #ith Top Tar!ert Model53D Grid dialog !o2 3. elect the Stratiraphic interval option to !e #or)ed %rst for the de%nition of the 'ones$ fro" the pll+do#n "en in the pper right part of the dialog. This inter(al #ill !e co"pleted 0para"eters speci%ed and the +pply !tton "st !e pressed !efore "o(ing to the ne2t inter(al. These "ain inter(als are the inter(als de%ned in the Ma)e 8ori'ons process. ;ote that only one inter(al can !e calclated at a ti"e and each hori'on deli"its a stratigraphic inter(al$ 4. /or the #op #ar$ert – #op 1ess inter(al there are three isochors 0therefore 3 'ones. /or the #op 1ess – #op 2tive inter(al these are t#o isochors 0& 'ones. There #ill !e no 'onation for the other stratigraphic inter(als listed$

)i! *&!**: Ma)e Fones #ith #op #ar$ert Model53D Grid #hile +ppend item in the ta$le and Set num$er of items in the ta$le appears

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. Insert the Isochores fro" the .sochores folder and the s!folder that corresponds #ith the stratigraphic inter(al yo are #or)ing on$ <. Insert isochores !y clic)ing on the !le arro# ne2t to the inpt %eld called .nput$ as sho#n !y /ig. 13.1&$ =. Insert #ell tops !et#een the isochores !y going to Hell Tops orted on Type and select the Hell Tops that correspond #ith the tratigraphic inter(al yo #or)ing on$ ! elect 0uild from $ase horizon and distri!te the volume correction Proportionally a"ong the (arios s! inter(als$ @. elect 0uild alon =ertical #hickness /#=#A$ *@! Dont forget to repeat procedre for the other tratigraphic inter(al$

)i! *&!*,: Isochores placed in inpt

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**! Go to Settin ta! and de+select the option that says:9 +ccordin to the settin in the BMakin Horizons processes Pane!

)i! *&!*&: Ma)e Fones #ith Top Tar!ert Model53D Grid dialog !o2 1&. Go to >ell +d?ustment ta! and specify that yo #ant to create a report fro" the >ell report options$ 13. Chec) Make well report option as sho#n !y /ig. 13.14$ 14. ,ress +pply to generate the inter"ediate hori'ons and 'one$ 1. ,ress 67 $

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)i! *&!*-: Ma)e Fones #ith Top Tar!ert Model53D Grid dialog !o2

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)i! *&!*4: #ell report for Top Tar!ert Model53D Grid appears

)i! *&!*5: Fones created in a 3D #indo# #hile ,illar Gridding appears 1>



)i! *&!*9: Fones created in 3D #indo# along #ith their #ells and falts

)i! *&!*: Fones displayed #hile 'ones nder Zones )ilter created 1@



)i! *&!*;: Fones displayed in a 3D #indo# #hile Intersections are displayed

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1otice: The colors of the 'ones can !e changed fro" the etting "en for each 'one$ fond nder the Zones lter in the !otto" of the 3D Grid 0DC.

)i!*&!,@: ettings for Fone 1

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Euality Control /ECA
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Make Layers The Ma)e Fones and Ma)e ! Fones processes are the t#o last steps in de%ning the (ertical resoltion of the 3D grid. The Ma)e Fones process is sed #hen a geological 'onation 0isochores is a(aila!le. This process step "ay !e s)ipped #hen no 'onation is gi(en. The Ma)e ! Fones process ena!les the ser to de%ne the %nal (ertical resoltion of the grid !y setting the cell thic)ness or the n"!er of desired cell layers. The %nal step in !ilding the strctral fra"e#or) is to de%ne the thic)ness and orientation of the layers !et#een hori'ons of the 3D Grid. These layers in con?nction #ith the pillars de%ne the cells of the 3D Grid that are assigned attri!tes dring property "odeling. The Ma)e Layer process #ill only "a)e a %ner resoltion of the grid and no inpt data are sed for this process. The ser can de%ne the (ertical resoltion of the grid !y setting the cell thic)ness$ de%ne a n"!er of cells or se a fraction code. Hhen specifying the cell thic)ness the 'one di(ision can either follo# the !ase or the top of the 'one. The layers shold !e de%ned !ased on the properties to !e "odeled. 7sally$ the layer thic)ness shold !e the thic)ness of the thinnest facies to !e "odeled. 8o#e(er$ it is i"portant to )eep in "ind that the n"!er of cells increases #hen the layer thic)ness decreases$ so yo shold not pt in "ore detail than necessary. Hhen "a)ing the %ne+scaled layering$ yo shold try to "a)e layers thin enogh to captre the i"portant Qo# nits. 8o#e(er$ the layers shold not !e too thin since that #ill increase co"pting ti"e It9s i"portant to focs on Qo# nits #hen de%ning the si'e of the layers$ no ?st on the thic)ness of each facies. Depending on the geology$ yo can choose to !ild the layers fro" the top$ the !otto" or se proportional layering. In the layering &3



process$ select the "ethod to !e sed and specify the cell thic)ness or the n"!er of cells 0layers. Ma)ing layers "ay !e done !ased on %eld geology as follo#s:

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•

•

•

•

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)ollow $ase: The layers #ill !e trncated to#ards the top hori'on. The ser de%nes the cell thic)ness. )ollow #op: The layers #ill !e trncated to#ards the !ase hori'on. /or the a!o(e t#o options yo can also choose to se a reference srface$ i.e. specify a srface #hich #ill !e sed as the srface to !ild fro". The srface can ta)e any shape$ and it "st e2ist in the Petrel 2Fplorer in order to !e sed. Proportional: The s" of layers #ill !e constant in the entire 'one$ independent of thic)ness of 'one. The ser speci%es the n"!er of layers to insert. )raction: This is actally a proportional #ay of !ilding the layers !t yo can specify relati(e thic)ness !et#een layers. /or instance: 1$ &$ 1 #ill generate three layers and the "id layer #ill !e t#ice as thic) as the top and !ase layers. Com$ination: e.g. follo# top and sing depositional srface to gide ho# the layers #ill !e placed.

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How to create layers 1. Go to Structural Modelin ite" in the Processes ,ane ,! Do!le clic) on the Layerin process! * #indo# pop p called Layerin with "#op #ar$ert Model%&D 'rid( as sho#n !y /ig. 13.&1$ this dialog has only one ta!. In principle it #or)s the sa"e #ay as the Make Horizon and Make Zones dialogs + a spreadsheet #ith the 'ones as ro#s and the speci%c 'one settings as col"ns$

)i !*&!,*: Layering #ith Top Tar!ert Model53D Grid dialog !o2 &! The dialog lists the 'ones generated in the Make Horizons and Make Zones processes. /or each 'one select the desired resoltion and layering layot. 4. Ma)e sre yo ha(e one or !oth of I and N intersections displayed in the graphics. Foo" in to see the fll (ertical inter(al. . Create the internal layering of the 'ones !y clic)ing OK $ and o!ser(e the reslts$ <. Change the option nder the Zone Division as sho#n in /ig. 13.&&$ =. The 8ori'ons$ Fones and Layering can !e re"o(ed !y clic)ing #ith the right "ose !tton on the 3D grid icon and selecting one of the Ae"o(e options$ &<



)i! *&!,,: Layers created in a 3D #indo#

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)i! *&!,&: #op #ar$ert created in a 3D #indo# along #ith their /alt ,olygons$ #ells$ Hell Tops$ /alt tic)s$ rfaces$ ,illar Gridding$ 8ori'ones$ and Fones

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)i! *&!,-: #op 1ess created in a 3D #indo# along #ith their /alt ,olygons$ #ells$ Hell Tops$ /alt tic)s$ rfaces$ ,illar Gridding$ 8ori'ones$ and Fones

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Chapter 13 - Vertical Layering

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