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Geology 493M*3D Horizon/Fault Interpretation Workshop

Labs 1 & 2 - Fault Interpretation and Correlation

*This workshop is based on procedural steps developed by Mike Enomoto of Seismic MicroTechnology Inc. Houston, TX.

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Fault/Horizon Interpretation UsingSeismic Micro-Technology’s Kingdom Suite

Labs 1& 2

Seismic Micro-Technology's Kingdom software is accessed throughthe Windows Start Programs Menu. In your program list selectKingdom Suite and then left-click on Kingdom.

NOTE: Left clicking the mouse is used to start, continue and end anactivity. Right clicking is ONLY used for displaying various pop-upmenus.

Project files are opened from the initial Kingdom Suite window(Figure 1). Click on Project then Open Project in the drop-downmenus.

Figure 1: The initial Kingdom Suite display window providesaccess to new and old project files.

Take a moment andCopy the folder Golden from your

H:\drive to your G:\drive

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Navigate to the Golden folder on your G:\drive. When you openthis folder, the following file should appear on the open file dialogbox.

Highlight the GOLDEN.tks file and open it.

The following window will contain an author list box and give youthe option to create your own project.

For this class, click on Create and enter your last name or otherpreferred identifier as shown below.

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Select the author you just created and then click OK.

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This exercise uses the Golden 3D data set, which is providedthrough the network drive. In this exercise, the "green reflector youinterpreted on the 2D lines running through the area will beinterpreted and carried through the 3D coverage of the area. Theentire 3D grid is interpreted. In this exercise, the major faults areinterpreted at the outset, since this will prevent autopicking of selectreflection events across fault planes.

Procedures:When you open a project under Kingdom, the basic windows layoutwill contain a 3D basemap (right) and project tree (left) (Figure 2).

Figure 2: Basic window layout showing project tree and 3D gridbasemap.

1. Left click on the 3D grid (Figure 2) to activate it. Line andcrossline numbers are plotted along the sides of thebasemap. In this example, position the mouse arrow on Line110. Right click and select Display In- Line 110. Theseismic line may now appear as shown below in Figure 3.

*Color display options will be covered in class, soyou might want to take some notes.

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Figure 3: Wiggle trace display of 3D line 110.

Display parameters are easily changed using the tool bar across theupper left corner of the seismic display window. To transformthe seismic response into a color display, click on the little scalebar in the tool bar (see below).

That should bring up the following window -

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In the settings window you’ll see several folders ( Horiz. Scale,Vert. Scale, Display Options, etc.) Open the Display optionsfolder and select Hi Res Color Raster and then OK. You maycontinue to get a black and white display of your data, butit is in

raster form. To use a different color scheme click on the colorbar editor (see below)

And in the window that opens, click on the little open folder icon oron Color Bar and then select. In the window that opens upselect blue to brown to white to brown 200.clb and then OK.

The following window will appear.

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The variable area wiggle traces that are superimposed on the colorraster can be switched off by clicking on the wiggle lines in theupper left corner of the seismic display window which will openup the following window.

Select No Overlays and then OK to get the following window.

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2. If you prefer another colorbar, left click on View and Colors.Click on File and Open and select a different colorbar. In mostcases, the name of the colorbar describes the colors and thenumber of colors in the colorbar. You can also use the left andright blue arrows in the color-bar select window to movethrough the color bars one-by-one. Close the color editor onceyou are satisfied with a colorbar.

3. To get back to wiggle traces, left click on View, Settings andthen select the Display Options folder and then select WiggleVariable Area. Or you can go there directly as before byclicking on the scale bar in the seismic display window as donebefore. Note the other display formats for future reference.

You can also change the trace amplitudes in the wiggle tracedisplay by using the F5 key to increase amplitude and the F6 key todecrease amplitude. Your variable area wiggle trace display shouldlook something like that shown below in Figure 4.

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Figure 4: Variable area wiggle trace display format of Line 110.

4. For additional changes to the display scales, left click onView and Settings or click on the scale bar at the top of theseismic line display window. Then go to Horiz. Scale and try 8traces per inch and Vert. Scale = 10 inches per second toprovide a close-up (Figure 5) view of waveform character in thevicinity of the well shown above (Figure 4). Use the scroll barsto position yourself within the line.

Figure 5: Close-up view obtained using 8 traces/inch and 10 inches/second.

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5. You can orient yourself to geographical directions bymoving the cursor on the seismic window (Figures 4 or 5) andwatch the cursor movement on the map. If the direction isbackwards hit the R key on the keyboard to reverse the linedirection.

6. The colorbar may or may not be displayed on the seismicwindow. To display colorbar, left click on View and Toolbarsand then Color Bar. A check indicates “on”. You can also addand remove the color bar directly from the seismic displaywindow by clicking on the color bar icon circled below.

7. Display features can also be accessed directly using thebuttons (Figure 6) in the upper left corner of the trace window.

8. On the seismic line, several faults are prominent. Many ofthese faults are easy to correlate others are not. Now would be agood time to assign a name to at least two of the major faults,the down to the south synthetic and down-to the north antitheticfaults. To assign the faults, right click on the seismic windowand select Fault Surface Management. From there, select theCreate tab and enter a name and color for the antithetic fault.Left click on Apply. Enter a name and color for the major faultand then either OK or Apply. Create new faults if desired,You're now in the fault picking mode with the last created faultactive.

Before we proceed, note that I have changed the color bar toLandmark.CLB. My display (see below) was set to Horiz. Scale= 20 traces per inch and Vert. Scale = 3.5 inches per second.Click on the R button so that cross-line numbers run from 120to 0, left to right across the seismic display window. You’rewelcome to choose different display parameters. Don’t forgetthat you can also adjust the relative amplitude of the tracesusing the F5 and F6 keys. Take a few moments and experiment.

Figure 6: Shortcut buttons on the line display window. Buttons, left to right, selectseismic line, wiggle overlay, vertical seismic display scale, color bar editor, a toggleswitch to display the color bar, and two zoom control buttons. The drop downwindow at right allows the user to select from time or other data type.

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9. Display the fault toolbar to allow for quicker selection of thefaults you wish to pick. To do this left click on View andToolbars and then Faults. All the displayed faults are present,including Unassigned. Hot keys are available: “D” enters theuser into the fault digitization mode, “A” assigns a fault, and"S" de-assigns.

10. To start picking your fault, left click on one of the faultnames. To begin digitizing hit the D-key; then start at the top ofthe fault and begin left clicking on the fault break that coursesthrough the seismic data. A rubber band should appear as yougo from point to point (Figure 7). Continue left clicking pointsalong the fault until you either need to scroll vertically orhorizontally to view fault extensions outside your current view(Figure 7). You can use the scroll bar to move the display sothat more of the fault is visible, however, it is easiest just to holdthe mouse arrow about a quarter of an inch above the bottom ofthe display window, which will cause the display window toslide down. Continue until you can no longer pick this fault.Double click to end.

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If you enter a point you don’t like, you can back up or deletethe last point by hitting the Esc key

Figure 7: Individual points digitized along the fault appear asblack squares connected by a thin black line (or rubber band).

11. Left click on the other fault displayed in the Faultsdigitizing menu to activate it and then hit the “D" key to begindigitization. Begin picking the second fault. If you choose topick some of the other faults on the Faults Toolbar, simplyactivate the appropriate named or unassigned fault, hit the “D”key and start picking. The two faults you just picked shouldappear as shown in the montage below (Figure 8). The numberof points used to digitize the fault will vary from interpreter tointerpreter.

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Figure 8: Project tree (back left) and basemap (right) lie in thebackground behind seismic Line 110 (right) and the Faultsmenu (small window at left). Faults just digitized on thenorthern end of the line appear as shown above.

12. The fault remains active so long as the square dots arepresent. If the fault is not active and you want to edit it, justclick on it. When a fault is selected for further editing, littlehandles appear on each digitized point. To move points, activatethe fault and then left click-and-hold on the digitized faultpoint. As you move the mouse, the digitized point will alsomove. If you move a small distance, you may have to use theEsc key to undo the rubber band.

13. If you would like to move the entire fault line, first activatethe fault and then hold the Ctrl key and then left click and holdon any part of the fault line. Move the line to wherever you likeand then release the mouse button and Ctrl key.

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14. To delete a fault segment, make it active and then hit thedelete key on your keyboard.

15. To add points, left click on an existing point, add theappropriate intervening points, and double click on anotherexisting point.

16. To remove consecutive points, left click on an existingpoint, skip the 'bad' points and double click on an existing point.

17. If you'd like to change the active fault, left click on thenew fault to activate it or select from the Faults Menu. If thenew fault has no existing digital points, you must hit "D" oneither the keyboard or Faults Menu.

18. To assign an unnamed fault, activate the fault name,activate the unassigned fault line and then hit the A-key.

19. To de-assign a named fault, activate the fault line and thenhit the S-key.

20. Once the faults have been picked on this line, you can beginpicking the faults on a grid of lines extending through theentire 3D data base. The interpretations are usually madeevery few lines. You can skip through the data base aconstant number of lines each time. To set the skipincrement left click on View, then Settings, and then openthe Seismic folder. In the Seismic folder you can Set LineSkip Increment to 20 and then OK. (Note a much easierway to do this is to type the number directly into thewindow that sets between a couple blue arrows at the top ofyour seismic display window.

Now whenever the right arrow on the keyboard is hit, theline displayed will increase by 20. If the left arrow is hit,the display will decrease by 20. If a cross line is displayed,the up and down arrow keys will work likewise.

21. Go to line 130 and digitize the main down-to-the-southfault and antithetic fault.

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22. Once an assigned fault has been picked on at least twolines, a fault surface is automatically created. To view faultsurfaces in map view go to the Project Tree and double click onthe appropriate fault icon (Figure 9). This opens a new mapwindow where the fault may be displayed as either a faultsurface or segments.

Figure 9: To display a fault surface double click the desiredname listed in your project tree.

Map view of fault surface is shown below (Figure 10).

Double Click

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Figure 10: The large down-to-the-south fault is displayed inmap view. Color-coded two-way travel times appear in the colorbar at right.At this point your interpretation consists of only one line.

At this point, complete your fault interpretations. Carry both thesynthetic and antithetic faults through the entire 3D data cube.

Once you’ve completed your fault interpretation, you shouldhave a more complete view of travel time variations toindividual fault surfaces.

To toggle from planes to segments, go to View, Fault DisplayMode and select either Fault Surface or Fault Segment.The fault segment display is shown below in Figure 11.

Figure 11: Fault segment display of the main down-to-the-southfault.

23. Display features can also be accessed directly using thebuttons (Figure 12) in the upper left corner of the map window(Figure 11).

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Note Fault Surface is selected in the window at right (see Figure12 below).

Figure 12: Shortcut buttons available on the map displaywindow. Buttons, left to right, allows the user to Select faultsurface to display, Select Contour Overlay, Set ContourParameters, Set Scales, Edit Colorbar, Show Colorbar,magnification control buttons, and a selection window thatallows you to switch back and forth from Fault Surface andFault Window displays.

In the fault segment display shown below for the antithetic fault,note that my picks for the fault on lines 110 and 120 appearout of place. Take a close look at your own correlations atthis point and try and resolve any misinterpretations thatmight have occurred.

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24. Display the fault surface in seismic view so that anymiscorrelation can be quickly seen. To do this, go to a seismicwindow and right click, go to Fault Surface Management, andthen Display. In the Display window verify that Both isselected for Display Type (Figure 13). If “Both” is selected,two lines are visible in seismic view, the straight line connectingthe digitized points and the interpolated fault surface.

Figure 13: Fault Management window. Select Both to displayboth the individual fault-trace picks and the interpolated line fitto these points (see step 24 above).

Make corrections to your interpretation if needed and proceed.

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25. Complete fault picking: Be sure to extend yourinterpretations east to Line 145. Note that the solid green linethat now appears on the seismic displays represents andinterpolated or extrapolated fault surface (Figure 14). Thisprojection is displayed as a guide only and does not representthe actual fault surface. When complete return to line 90 andcontinue to the west. To go to line 90, left click on Line andthen Select or left click on the arrow button in the seismicdisplay window which brings up the same window. Type in 90and be sure the line button is on and that the 3D survey isdisplayed. Hit OK. If you would like to view the faults instrike direction or on an arbitrary line, right click on thedesired cross line in the base map window and then displayline.

Figure 14: Interpolated fault surface shown as solid green lineon seismic Line 105.

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Again to display the fault surface make sure fault surface isselected in the text box to the right of the toolbar on the faultsurface display. The map of your antethetic fault should looksimilar to that shown below.

26. To display line with an arbitrary orientation through thesurvey, right click on amap window, selectDigitize Arbitrary Line,left click on the startingpoint, continue leftclicking on each bend inthe line (Figure 15) andthen double click to end.The digitized line willappear (Figure 16).

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Figure 15: An arbitrary line overlay is extracted from the 3Dsurvey using the digitize arbitrary line option.

Remember that the solid green line is the interpolated antitheticfault surface and it may jump around quite a bit between lineswhere the fault surface was digitized. Take a close look at yourarbitrary line.

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Figure 16: Arbitrary 2D line digitized in Figure 15.

Note that along our arbitrary line some of the features showingup in the time map are associated with errors in theinterpolation. The high (blue color) and low (red color) areaadjacent to each other on the southeast end of the arbitrary lineare clearly associated with errors in the interpolation. Note thatthe colors indicate that the fault drops abruptly south from 0.4seconds to more than 2 seconds.

We made our initial interpretations on a course grid, every 20lines through the 3D database. At this point, take someadditional time and make your interpretations every 10 lines;then recheck your time map using the digitize arbitrary lineoption or by selecting appropriate In-Lines and Cross-Lines.

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At this point, your fault surfaces will be correlated across theentire survey area. The north-dipping (antithetic) fault surface,for example, will appear as shown below (Figure 17).

Figure 17: Color raster display of north-dipping (antithetic) faultsurface.

27. Continue picking faults, in the western direction. You canedit interpolated fault picks by first selecting the desired faultas the active fault in the Fault Management Window, and thenhitting the D key to digitize. If you wish to correct a portion ofthe interpolated picks simply begin picking points through thedesired region. Double click to complete digitization. Yourpicks will replace the interpolated picks.

Note: If a fault has been extended too far, you can delete aportion of the interpolated fault line by digitizing the extendedportion, and double clicking to replace the interpolated line withyour picks. Then click on the bad pick and drag the rubber bandto the first good pick and double click. All points beyond thelast pick will be deleted.

In the next lab we will carry the “1.3” second reflector through the 3D data set.