Advanced Interpretation 7.4

Advanced Interpretation Geophysical Tools for Enhanced Results

© 2012 SeisWare International Inc. Calgary, Alberta, Canada All rights reserved

© 2012 SeisWare International Inc. Calgary, Alberta, Canada

All rights reserved.

SeisWare Version 7.04 REV 0 February 2012

Advanced Interpretation

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CONTENTS 3D Seismic Visualizer................................................................................................................ 1 Fault Interpretation.................................................................................................................. 29 Well Planning........................................................................................................................... 49 Time to Depth Conversion ...................................................................................................... 56 Log Editor ................................................................................................................................ 69 2D Modeling/Cross Section .................................................................................................... 87 Horizon Smoothing and Computing Attributes.................................................................... 102 Seismic Zone Attributes........................................................................................................ 108 Wavelet Analysis ................................................................................................................... 115 Attribute Calculator ............................................................................................................... 128 Spectral Decomposition........................................................................................................ 137 Automatic Mistie Analysis .................................................................................................... 146 Appendix A: Depth Seismic .................................................................................................. 159 Appendix B: SeisWare Glossary .......................................................................................... 162

FIGURES

Figure 1: 3D General Visualizer Properties .................................................................................. 2 Figure 2: 3D Seismic Properties Window ..................................................................................... 3 Figure 3: Red White Blue Color Bar ............................................................................................. 4 Figure 4: 3D Volume Loaded in Seismic Visualizer ...................................................................... 4 Figure 5: General Toolbar and Interaction Toolbar ....................................................................... 5 Figure 6: Scale Toolbar ............................................................................................................... 7 Figure 7: Slice Toolbar and Animation Toolbar ............................................................................ 9 Figure 8: Contour Overlaying Grid ............................................................................................. 12 Figure 9: Loading Horizons........................................................................................................ 14 Figure 10: Interaction of Horizon and Seismic ............................................................................ 15 Figure 11: Selecting Grids ......................................................................................................... 16 Figure 12: Selecting Overlay ..................................................................................................... 17 Figure 13: Wells Properties ....................................................................................................... 18 Figure 14: Volume Toolbar ........................................................................................................ 20 Figure 15: Adjusting Vertices ..................................................................................................... 21 Figure 16: Moving Volume ......................................................................................................... 21 Figure 17: Opacity Graph .......................................................................................................... 22

SeisWare V 7.4, 2012


Figure 18: Data Properties for Seismic Opacity .......................................................................... 23 Figure 19: Opacity Graph........................................................................................................... 24 Figure 20: Seismic Volume with Opacity Applied ........................................................................ 25 Figure 21: Light Intensity Slider Bar ........................................................................................... 26 Figure 22: Seismic Viewer – Fault–Horizon Contacts ................................................................. 30 Figure 23: Basemap – Fault–Horizon Contacts .......................................................................... 31 Figure 24: Pick Horizons Window .............................................................................................. 32 Figure 25: Configuration Window ............................................................................................... 32 Figure 26: Seismic Display Properties Window .......................................................................... 33 Figure 27: Select Fault to delete Dialog...................................................................................... 36 Figure 28: Seismic Viewer – Selected Fault Segment ................................................................ 37 Figure 29: Reassign Fault Segment Window.............................................................................. 38 Figure 30: 3D Visualizer with Parallel Faults .............................................................................. 38 Figure 31: Basemap – Choosing Faults to Reassign .................................................................. 39 Figure 32: Triangulate Faults Window ........................................................................................ 41 Figure 33: Seismic Viewer – Triangulated Faults........................................................................ 41 Figure 34: 3D Visualizer – Fault Triangulation Planes ................................................................ 42 Figure 35: 3D Visualizer – Fault Triangulation Edges ................................................................. 42 Figure 36: Fault to Horizon Window ........................................................................................... 45 Figure 37: Fault Polygons/Contacts Window .............................................................................. 47 Figure 38: Basemap – Fault Polygons ....................................................................................... 48 Figure 39: Well Planning Dialog ................................................................................................. 49 Figure 40: Well Plan in the Seismic Viewer ................................................................................ 53 Figure 41: Editing nodes on the Basemap.................................................................................. 54 Figure 42: Editing nodes in the 3D Seismic Visualizer ................................................................ 55 Figure 43: Choose Time/Depth Method Window ........................................................................ 56 Figure 44: Time to Depth Interval Velocity .................................................................................. 58 Figure 45: Select Tops Window ................................................................................................. 61 Figure 46: Grid Parameters Window .......................................................................................... 63 Figure 47: Output grid ................................................................................................................ 66 Figure 48: Zoom Toolbar ........................................................................................................... 70 Figure 49: Select Curve Alias Window ....................................................................................... 71 Figure 50: Log Editor Window .................................................................................................... 72 Figure 51: Select Curve Alias Window ....................................................................................... 73 Figure 52: Moving Tracks .......................................................................................................... 74 Figure 53: Synthetic Properties Selection................................................................................... 75 Figure 54: Synthetic Track ......................................................................................................... 76 Figure 55: General Track Properties .......................................................................................... 78 Figure 56: Individual Track Properties ........................................................................................ 79 Figure 57: Track Properties – Fill Properties .............................................................................. 80



Figure 58: Fill Above Value and Fill Below Value ....................................................................... 80 Figure 59: Edit Curve Icons ....................................................................................................... 81 Figure 60: DT Sonic Curve Selected for Editing ......................................................................... 84 Figure 61: Save Curve Dialog .................................................................................................... 85 Figure 62: Editing Tops Toolbar ................................................................................................. 85 Figure 63: Cross Section Properties .......................................................................................... 88 Figure 64: General Track Properties .......................................................................................... 89 Figure 65: Track Properties ....................................................................................................... 90 Figure 66: Model Properties ...................................................................................................... 91 Figure 67: Well Selection from Basemap ................................................................................... 93 Figure 68: Apply Log Template .................................................................................................. 94 Figure 69: Correlations Window................................................................................................. 95 Figure 70: Cross Section with correlations, being edited ............................................................ 98 Figure 71: Output 2D SEG-Y Dialog .......................................................................................... 99 Figure 72: Generated Model .................................................................................................... 100 Figure 73: Saving the Model .................................................................................................... 101 Figure 74: Horizon Smoothing/Attributes Window .................................................................... 104 Figure 75: Select Output Horizon Names Window ................................................................... 105 Figure 76: Seismic Zone Attributes Window ............................................................................. 112 Figure 77: Seismic Zone Attributes Window – Select Wavelet Section ..................................... 113 Figure 78: Add Wavelet Window.............................................................................................. 121 Figure 79: Wavelet Analysis Window ....................................................................................... 123 Figure 80: Add Wavelet Window.............................................................................................. 124 Figure 81: Wavelets Section with New Wavelet ....................................................................... 125 Figure 82: QC Wavelets Window ............................................................................................. 126 Figure 83: Attribute Calculator Window .................................................................................... 132 Figure 84: Semblance Cube in the Seismic Viewer .................................................................. 134 Figure 85:Seismic Color Properties for Semblance .................................................................. 135 Figure 86: Semblance and Curvature in the 3D Seismic Visualizer .......................................... 136 Figure 87: Spectral Decomposition .......................................................................................... 140 Figure 88: Spectral Decomposition Window Parameters .......................................................... 141 Figure 89: Spectral Decomposition Output............................................................................... 142 Figure 90: Time Slice .............................................................................................................. 143 Figure 91: Spectral Decomposition – Windowing Parameters .................................................. 144 Figure 92: Output .................................................................................................................... 145 Figure 93: Select Mistie Run Window. ..................................................................................... 150 Figure 94: Automatic Mistie Analysis Window .......................................................................... 151 Figure 95: Select Seismic Lines Window ................................................................................. 152 Figure 96: Quick Mistie – Zoom and Mistie Analysis Windows ................................................. 154 Figure 97: Add Jump Tie Window ............................................................................................ 157


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3D SEISMIC VISUALIZER The 3D Seismic Visualizer is a tool that enables you to view all of the data in your project in 3D space. You are able to load in your seismic, with existing interpretation and integrate this with your wells and culture information to create a cohesive view. After you have loaded all of your data into the 3D Seismic Visualizer, you can save the display and create saved images for use in other applications. You can: o load 2D and 3D seismic data o display trace, line, time and horizon slices for 3D volumes o load multiple 3D volumes and independently adjust their properties o load horizons and grids as structure surfaces with attributes as surface color overlay, and independently adjust their properties o display faults, grids and horizons as surfaces or wire meshes o rotate, zoom, pan, change vertical exaggeration and control light direction o print images as .bmp files to insert in other software or print To open the tool, select 3D Seismic Visualizer from the Launch menu of the Main Launcher. The 3D Seismic Visualizer always defaults to a blank view, until you specify the data to display. To load data, and customize the display, you will be using the General 3D Visualizer Properties.

Loading Seismic Data You can load both 2D and 3D seismic data into the 3D Seismic Visualizer. You can load multiple volumes at one time, either in time or in depth. By default, only the working set versions of


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your seismic is displayed, but you can view all volumes by toggling off the Display working set only option. After you select any of the volumes, the displays can be individually configured by highlighting the volume from the Visible Seismic list and then selecting the Properties button on the bottom right. Clicking on the Properties button launches a Properties window that allows you customize the appearance of the data item. You can change colors, scaling methods and time or depth extents. If no settings are changed, the entire 2D line or 3D volume will display with the default display properties.

Exercise  Select Load Data from the File menu. SeisWare opens the General 3D Visualizer Properties (see Figure 1). Alternatively you can select General Properties from the right mouse button menu, or use the General Properties icon (

).

Figure 1: 3D General Visualizer Properties



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 In the Displayed Data section of General 3D Visualizer Properties select 3D Seismic.  Move “nsask MIG 0 Migrated Stack” from Available Seismic 3D to Visible Seismic 3D and press .  Highlight “nsask” in the Visible Seismic 3D column and press . SeisWare opens a window titled “3D Seismic Properties: nsask MIG 0 Migrated Stack” (see Figure 2).

Figure 2: 3D Seismic Properties Window

 Select Data Properties and ensure that Trace slice, Line slice and Time slice are selected, and that Volume is not selected.  Toggle off Time slice and press Turn Time slice back on.  Enter a Start Time of “500” and an End Time of “1500”.


.

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 Select Seismic Color Properties from the list of 3D Seismic Properties.  Select the “Red White Blue” color bar from the dropdown list.

Figure 3: Red White Blue Color Bar

 Select Posting from the list of 3D Seismic Properties and ensure that Show Posting is not selected.  Press Properties.

to exit the 3D Seismic

 Press to exit the General 3D Visualizer Properties. SeisWare now displays the volume in the Visualizer (see Figure 4).

Figure 4: 3D Volume Loaded in Seismic Visualizer



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Navigating in the 3D Seismic Visualizer Navigating within the 3D Seismic Visualizer can be accomplished using the tools on the General Toolbar and Interaction Toolbar (see Figure 5).

Figure 5: General Toolbar and Interaction Toolbar

Rotation Mode After the volume has been loaded you will be in Rotation mode ( ) and the cursor will look like a hand (

). In this mode you

can rotate and move the display on all axes by left clicking and dragging. While in Rotation Mode, to temporarily switch to Selection Mode, hold down the Shift key, or hit R to switch permanently.

Selection Mode Selection Mode is also required when manipulating a volume, and when selecting slices within the Visualizer. Selection Mode is activated by pressing the selection mode icon ( cursor will now look like an arrow (

). The

). To temporarily switch to

Selection mode while in Rotation Mode, hold down the Alt key, or hit V to switch permanently.

Orienting Displays To help you orient yourself, direction arrows are always visible on the bottom right hand side of the Visualizer. Clicking Plan


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View (

) will orient the screen as if you were viewing a

Basemap with the Z axis coming directly out of the screen. Clicking Depth View (

) orients the display such that the north

axis is exiting the screen.

Defining Home Position Similar to the Basemap you can define a home position in the view by pressing the Define Home Position icon (

). To return

to this position at any time press the Go To Home Position icon ( ).

Additional Movements The Pan icon (

) allows you to move the display with no

rotation. This is useful when you have an exaggerated vertical display. If you are in rotation mode you can click and hold down the centre mouse wheel to pan without selecting the icon, but this only works if you are already in a rotation mode. The Zoom icon (

) allows you to zoom in and out by moving

the cursor towards and away from you. You can also use the centre mouse wheel to slowly move the display in and out.

Exercise 1. Navigating the 3D Seismic Visualizer  Practice rotating the seismic display in Rotation mode.



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 Click the Vertical Rotation (

) and Horizontal

Rotation ( ) icons respectively and left click and drag on the seismic display. SeisWare rotates the display around an axis.  Click the Pan icon (

). The cursor changes to look

like a hand with four arrows ( in both directions.  Click the Zoom icon (

). Pan the display

). The cursor changes to

look like a pointed finder with an arrow ( the display in and out.

). Zoom

 Click the Go To – Centre and Zoom In icon ( The cursor changes to a viewfinder (

).

).

 Left click on an area you want to zoom in on. SeisWare will both centre the display and zoom in.  Press the Fit View icon ( volume.

) to view the entire

Setting the Scale To get an appropriate view in the 3D Seismic Visualizer you made need to modify the vertical and horizontal exaggeration of the display. This can be done by adjusting the settings on the Scale Toolbar (see Figure 6).

Figure 6: Scale Toolbar

Use the up and down arrows to adjust the scale in the X, Y or Z direction. Alternatively you can manually enter scale values. If


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you want different scales in the X and Y direction you need to turn off the Lock X and Y aspect ratio icon (

).

Exercise 1. Defining the scale  Press the up arrow ( ) next to the Z field to increase the z-scale exaggeration.  Type the value “5” into the Z field.  Press the up arrow next to the X field to increase the x-scale exaggeration.  Turn of Lock X and Y aspect ratio (

).

 Press the down arrow ( ) next to the ) Y field to decrease the y-scale exaggeration independent of the x-scale exaggeration.  Turn on Lock X and Y aspect ratio (

).

 Return the value in the X filed to “1”.

Scrolling through Seismic Data To move through the seismic volume you can click and drage objects while in selection mode, or you can use the tools on the Slice Toolbar and Animation Toolbar (see Figure 7). These tools allow you to animate through slices, scroll through slices, or manually enter a slice value. The toolbar has the Slice Type (inline, crossline, time, horizon), Volume Name and a Position slide bar that will display the actual position within the 3D where the currently selected slice



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is. When a slice is selected, there will be a red highlight around the slice. When scrolling in the Seismic Visualizer, you can have the Seismic Viewer update with the current slice. For the Visualizer and the Seismic Viewer to communicate the talk ( (

) and listen

) icons must be on in both applications.

Figure 7: Slice Toolbar and Animation Toolbar

Exercise 1. Scrolling through seismic data  To move a slice, make sure you are in selection mode ( ), left click on any slice so that it highlights red and then drag to the new position. Try this on all of the slice types.  Select “Inline” from the Slice Type dropdown.  Press the Animate Forward icon ( ). SeisWare scrolls through the inlines at the selected Increment and Speed.  Press the Stop icon ( ) when you reach a slice of interest to stop the animation.  Use the position slider to move the slice. It only moves the slice specified in the Slice Type dropdown, so the inline should be moving  Repeat this procedure, selecting Crossline and Time from the Slice Type dropdown.


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 Select “Inline” again from the Slice Type dropdown. Ensure that the talk ( on.

) and listen (

) icons are

 Open an inline in the Seismic Viewer on the “nsask” volume.  Type “125” in the Position field in the 3D Seismic Visualizer and press Enter on your keyboard.

Loading Data Data is loaded from the Displayed Data section of the General 3D Visualizer Properties. All data items are selected individually; however entire data types can be turned on and off from the Data Visibility page.

Loading Horizon Data Single or multiple horizons can be loaded into the 3D Seismic Visualizer. Any overlay can be placed on the horizon structure, such as an amplitude horizon, Wavelet Analysis output horizon or curvature horizon. As with seismic, you are able to set the display parameters for each horizon independently using the Properties button. To globally change the properties for all displayed horizons in one step select Horizon Display Properties in the General 3D Visualizer Properties window, and ensure that Apply to loaded data is checked on.

Loading Grid Data Single or multiple grids can be loaded into the 3D Seismic Visualizer. Like horizons, any overlay can be placed on the grid



surface. Unlike horizons, a grid doesn’t need to be associated with seismic data to be loaded. To change the properties of a single grid you can select the grid a press the Properties button. To globally change the properties for all displayed grids in one step select Grid Display Properties in the General 3D Visualizer Properties window, and ensure that Apply to loaded data is checked on. If you want to view a depth grid, you can change the Z units of the Visualizer to depth units. This setting is accessed from the Visualizer Properties section of General 3D Visualizer Properties.

Loading Culture All of the culture in your project is available to be loaded in the 3D Seismic Visualizer. By default, when a culture layer is loaded into the Visualizer the entire layer is loaded. It is drawn as a flat layer at a Z value of 0. You can use the Culture Z slider to reposition the culture layers to any Z position. This makes it easier to orient yourself closer to a region of interest. Contour culture layers are handled slightly differently since contours have Z values associated with them. They will be draped over the grid surface (see Figure 8). You may need to exaggerate the Z scale for full impact. To limit the extents of your view, use the Clip View feature described on page 26.


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Figure 8: Contour Overlaying Grid

Loading Wells, Tops and Curves All of your well data can be loaded into the 3D Seismic Visualizer, including tops and curves. When looking at time data, if the wells contain velocity information, they will plot accurately in time. By default, if there is no velocity information when viewing well on a time volume, the vertical stick will be drawn to the full extents of the data loaded.

Loading Faults The 3D Seismic Visualizer is helpful for correlating fault segments and for checking fault plane triangulation. Fault segments will update interactively as they are picked or edited in the Seismic Viewer, so it is helpful to keep the Visualizer open as you are picking faults.



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Exercise 1. Loading horizon data  Open General 3D Visualizer Properties (

).

 Select Horizons from the Displayed Data list.  Move horizon “H” from the Available Horizons list to the Visible Horizons and Overlays list (see Figure 9). Click

.

 Select horizon “H” from the Visible Horizons and Overlays list and press Overlay.  Select “H AMP” from the Select Overlay list. Click then click General 3D Visualizer Properties window.

in the

 Select horizon “H H AMP” from the Visible Horizons and Overlays list and press Properties.  Select a new color palette from the dropdown menu.


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Figure 9: Loading Horizons

 Toggle between Show surface and Show triangle edges in the Horizon Appearance section.  Toggle between Using the color palette and Using the object’s surface color in the Color 3D Surface section.  Return the settings to Show Surface and Using the color palette and click

.

 Use the Transparency slider bar to adjust the transparency of the horizon.  Click to exit the Properties_Horizons: H H AMP window.  Zoom in on the faulted area in the NE corner of the display.  Move the inline slice to see the interaction between the horizon and the seismic data (see Figure 10).



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Figure 10: Interaction of Horizon and Seismic

2. Loading grid data  Open the General Properties window (

).

 Remove the “H” horizon from the display.  Select Grids from the Displayed Data section of General 3D Visualizer Properties.  Move “E Grid” from the Available Grids list to Visible Grids and Overlays list (see Figure 11). Click .  Select “E Grid E Grid” from the Visible Grids and Overlays list and click

.

 Select a new color palette from the dropdown menu.  Toggle between Show surface and Show triangle edges in the Grid Appearance section.  Use the Transparency slider bar to adjust the transparency of the grid.


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 Click to exit the Properties_Grids: E Grid E Grid window.

Figure 11: Selecting Grids

 Highlight “E Grid” in the Visible Grids and Overlays list and click

.

 Select “E AMP Grid” from the Select Overlay list and click

(see Figure 11).



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Figure 12: Selecting Overlay

 Click . SeisWare now displays the relief of E Grid with the color mapped as E AMP Grid. 3. Loading Culture Data  With E Grid still displayed select Culture from the Displayed Data section of General Properties.  Move “E Contour” from Available Culture Layers to Visible Culture Layers.  Click

.

 Move the layer “Channel_Text” into Visible Culture Layers.  Click

.

 Use the Culture Z slider bar to move the culture to an appropriate depth.  Remove all culture and grid data from the Visualizer.


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4. Loading Well Data  Select Wells from the Displayed Data menu in General Properties  Select a group of wells by left clicking and dragging out at area on the Basemap.  Click

.

 Click Remove All then select well “100232” from the Available Wells list and press

.

 Click on Wells Display Properties in the General 3D Visualizer Properties window (see Figure 13).

Figure 13: Wells Properties

 Change the Text Size to “20” and the Bore Diameter to “20”. These sizes are in surface units, either metres or feet depending on how the project has been configured.



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 Adjust the Label Z Position.  Select Tops in the Displayed Data menu in General Properties.  Make sure the View Tops has been selected.  Adjust the appearance of the tops in the Tops Display Properties section of the Visualizer Properties.  Select Log Curves in the Displayed Data menu in General Properties.  Click

in the Available Wells list.

 Select the “DTCO” curve from the Available Log Curves list.  Click

.

 Adjust the appearance of the curve in Log Curve Display Properties.  Remove the wells from the Visualizer. 5. Loading fault data  Select Faults from the Displayed Data menu in General Properties.  Click to move both available faults from the Available Faults list to the Visible Faults list.  Click . SeisWare now displays the faults in the Visualizer.  Click on Faults Display Properties.  Toggle Show triangulated surface on and off.  Toggle Show triangle edges on and off.  Toggle Show Segments on and off.


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 Adjust the Transparency of the fault surfaces.  Remove the faults from the Visualizer.

Defining Region of Interest Region of Interest allows you to create a rectangular volume within the 3D that can be moved independently. Use this feature to create pseudo chair diagrams and other unique displays when combined with slice displays. Adjusting the region of interest is done using the Volume Toolbar (see Figure 14).

Figure 14: Volume Toolbar

Exercise  From the Volume Toolbar select the Toggle Volume Visibility icon ( ). The entire 3D volume becomes opaque, and the icon will show that it is enabled ( ).  Click the Toggle Region of Interest icon ( ). You will now see the volume outlined with tabs on the vertices.  Click on the Selection Mode icon (

).

 Left click and drag on the tabs to change the size of the volume (see Figure 15).



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Figure 15: Adjusting Vertices

 Left click and drag on the sides of the volume to move the entire volume (see Figure 16).

Figure 16: Moving Volume


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 Deselect Region of Interest and Volume Visibility.

Seismic Opacity The opacity of an entire volume can be adjusted based on its amplitude content. Certain amplitudes and dead traces can be rendered transparent. The opacity can also be adjusted for horizon and grid data. The Opacity Graph is represented by Opacity values on the Y axis, ranging from 1.0, or fully opaque, to 0, or fully transparent. The X axis represents the range of amplitudes in the seismic file. The graph in Figure 19 will render the highest negative amplitudes in the volume fully opaque and all other values transparent.

Figure 17: Opacity Graph

When drawing the graph, any position where no line is drawn that section of the color palette will be made fully transparent.



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Once the graph is drawn you can adjust the vertices by clicking and dragging nodes. If you commonly use the same graph you can save (

) and load (

) graphs.

Exercise  Select 3D Seismic from the Displayed Data section of General 3D Visualizer Properties.  Select “nsask” from the Visible Seismic 3D list and press

.

 In the Data Properties section enter a Start Time of “650” and an End Time of “725”. Turn off Trace slice, Line Slice, and Time Slice and turn on Volume and Full Volume (see Figure 18). Press .

Figure 18: Data Properties for Seismic Opacity


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 Select Seismic Opacity to from the 3D Seismic Properties window.  Select the Draw Lines tool ( / ) and use your cursor to draw a graph similar to that in Figure 19.

Figure 19: Opacity Graph

 Press . You will only see the areas containing the lowest amplitudes in the file displayed, including the channel, the tributary, and the faulting in the NE corner (see Figure 20).



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Figure 20: Seismic Volume with Opacity Applied

Adjusting Lighting The lighting in the 3D Seismic Visualizer can be adjusted to best highlight the feature you are trying to see. You can globally adjust the intensity of the light, and individually control the lights’ intensity along each individual axis (x, -x, y, -y, z and –z). You can access the Lights options fomr the General 3D Visualizer Properties, or using the Adjust Lights icon from on the General Toolbar (

)/

Exercise  Display “D Grid” and adjust the Z scale so that it is at least “50”.  Select Lights in the General Properties.  Adjust the intensity of the Directional lights and observe the effect on the grid display (see Figure 21).


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Figure 21: Light Intensity Slider Bar

 Individually turn the Directional Lights on and off and rotate the grid to see the result.

Clipping View By default the 3D Seismic Visualizer loads the full extents of any data item selected into the display. Sometimes larger culture objects make the default view very large. You can restrict the viewing area by using the Clip View option. Here you are able to set minimum and maximum X and Y ranges used for viewing the data. All data can be clipped using this utility. To clip the view on your map, open the General 3D Visualizer Properties. In the Visualizer Properties settings, turn on Clip View and select an area on the map to define the Visualizer extents.

Exercise  Right click in the 3D Seismic Visualizer and go to General Properties  Select Visualizer Properties.  Select . This will allow you to see the Min and Max X, Y and Z extents.  Click on

.



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 Go to the Basemap and define an area by left clicking, holding and dragging out a box.  Once the values for the extents have updated click . The data in the 3D Visualizer should now be limited to the area defined.  Click the Toggle Clipping icon ( the original view.

) to go back to

Printing You can create a bitmap (BMP), JPEG, PNG or TIFF file of the Visualizer image. These can be imported into other applications and printed. These may also be added to Basemap plots using the Montage Editor.

Exercise  Use the 3D Visualizer’s File menu, and choose Save to Image File.  Give the file a descriptive name, and press .

Saving Properties Save a 3D Seismic Visualizer display to a file so that you can recreate the display at a later time. You can Save Data and Properties which will save your entire display including the selected data and properties. You can also Save Properties which saves only the properties settings including sizes and colorbars. If you forget to save your settings, the last used settings are saved by default.


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Exercise  Use the 3D Visualizer’s File menu, and choose Save Data and Properties.  Name the file “Saved properties 1”  Select New from the file menu. This will remove everything from the Visualizer and leave you with a blank view  Use the File menu and select Open Data and Properties. Select the file “Saved properties 1.xml”. All of your data should be reloaded as you had left it.  Select New from the file menu.  Use the File menu and select Open Data and Properties. Select the file called “Last_data&properties_loaded_3DViz”. All of your data should be reloaded as you had last seen.



FAULT INTERPRETATION A typical fault interpretation workflow in SeisWare starts by creating fault segments in the Seismic Viewer. Faults are drawn as a series of connected nodes that can easily be edited. The picked segments can be viewed in the Seismic viewer, on the Basemap, and in the 3D Seismic Visualizer. Once a fault has been picked you can triangulate it to create a surface, contour it to highlight the surface, and grid it to apply color to its surface. You can also use the intersection of the fault with existing horizons to create a fault polygon, which can be used when gridding a horizon surface. There is a strong interaction between fault picking and the 3D Seismic Visualizer. Faults update automatically in the Visualizer as they are being picked, so you can constantly check you picking for quality and consistency.

Picking Fault Segments The picking utility, opened by selecting Pick from the Fault menu, is very similar to the horizon picking dialog. It lets you specify the name and display properties for the faults that will be used as you work. Clicking in the Viewer allows you to create connected node points.

Generating Fault/Horizon Contacts When a picked horizon intersects a fault segment, a contact is generated. These contacts can be used to generate fault polygons that can ultimately be used to create structure maps.


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When the fault and horizon intersect, SeisWare displays a horizon/fault contact circle on the seismic (see Figure 21).

Figure 22: Seismic Viewer – Fault–Horizon Contacts

On the Basemap, if there is only one contact, when you display the horizon, the circle will appear. If you have multiple contacts along a segment, chevron symbols indicate the horizon/fault contact, and the heave and direction of dip (see Figure 22).



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Figure 23: Basemap – Fault–Horizon Contacts

You might need to switch to a manual picking mode to pick through a fault, such as “Straight Line”, rather than an automatic mode, such as “Snap Stream”, because of data distortions near the fault. This will help ensure that SeisWare generates a proper horizon/fault contact. You can also configure the Horizon Picking dialog to Stop Picking at Faults. Open this by pressing the Configuration button on the Pick Faults dialog (see Figure 24).


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Figure 24: Pick Horizons Window

After you have opened the Configuration window you can turn on Stop picking at faults (see Figure 25).

Figure 25: Configuration Window

Correlation Polygon A correlation polygon can be used to move a portion of data from one side of a fault to another to help you pick seismic data



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on both sides of a fault. Click the Correlation Polygon icon(

)

and then cut out a section of seismic data with a series of left mouse button clicks. Right click to end the selection, then use your cursor to move the section. Pressing Delete on the keyboard will erase the polygon.

Projecting Fault Segments In many areas, it can be difficult knowing exactly where to place a fault segment because of poor data resolution. In these cases, you can project the segment locations from other inlines or crosslines to help locate the fault. You can turn on the 3D Inline Crossline Overlay from the Faults tab of the Seismic Display Properties (see Figure 26).

Figure 26: Seismic Display Properties Window


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SeisWare displays the faults as dashed lines for any segments that fall within the number of traces specified. You can use these as a guide for picking parallel faults through poor data areas.

Editing Fault Segments To change an existing fault segment you must first select the segment with the Fault Picking dialog open. You are then able to grab the nodes that exist along the segment to reposition. Clicking between nodes will insert a node at the point where you click. To add a node beyond the fault segment use the Insert key on the keyboard. You can delete a selected node by hitting the Delete key on your keyboard once and the again to remove the entire fault segment. You can also use the 3D Seismic Visualizer to check the segment editing. Refer to the 3D Visualizer’s Fault Data section, on page 12, for information about the 3D Seismic Visualizer. Whenever edits are made in the Seismic Viewer, the 3D Seismic Visualizer will show these edits so you can use this feature to check your work.

Displaying Faults on the Basemap The Fault Properties section of General Basemap Properties allows you to control the appearance of faults on the Basemap. The fault displayed on the map is made up of the nodes (squares), segments (lines), and the dip direction of the fault (arrow head). These components can be turned on in any combination. The color of the fault on the Basemap is the same as the color used in the Seismic Viewer and is set in the Fault Picking dialog.



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Correlating, Assigning, and Reassigning Segments Faults are connected by name and must be named before they can be picked. You can create a temporary fault called “Unassigned” and use this fault for picking all faults. These faults can be reassigned on either the Seismic Viewer or the Basemap. In the Seismic Viewer, you must first select the segment, and then reassign the fault from the Fault menu. Only the selected fault will be reassigned. On the Basemap, you can select single and multiple faults to be reassigned using the Assign Fault Segment icon (

). Using a

polygon selection feature, you are able to select the segments and then reassign the faults. When performing the assign function, you will always have the option to chose an existing fault name, or create a brand new fault.

Deleting Segments To delete faults from the Basemap, you can use the Delete fault segments icon (

). Once you’ve entered the mode you draw a

polygon around the fault segment that you want to delete. To complete the selection you can click your right mouse button to open the Select Fault to delete dialog (see Figure 27).


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Figure 27: Select Fault to delete Dialog

To delete segments in the Seismic Viewer, open the Fault Picking dialog, and select the fault to be deleted. Hit the Delete key twice. The first click will remove a node, but the second will remove the entire segment.

Exercise 1. Reassigning Fault Segments in the Seismic Viewer  As an example of reassigning an erroneously correlated segment in the Seismic Viewer, make the fault segment from fault EG1 active (see Figure 28).



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Figure 28: Seismic Viewer – Selected Fault Segment

 From the Seismic Viewer’s Fault menu, choose Reassign Fault Segment. SeisWare opens the Reassign Fault Segment window (see Figure 29).  Click on New Fault and then enter a Name, Color, and Type.  Click to reassign the fault. Note the changes on the Basemap and the 3D Visualizer.


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Figure 29: Reassign Fault Segment Window

 In the 3D Visualizer, drag the mouse to rotate the display and align the segments, to ensure that they are in the same fault plane. It is best to use the Basemap if you need to reassign more than one segment.

Figure 30: 3D Visualizer with Parallel Faults



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2. Reassigning Faults Segments on the Basemap  On the Basemap, check for the fault that you reassigned, because of its change in color.  Select the Assign fault segments icon ( ), click and drag a circle around the reassigned fault segment, and right click to finish (see Figure 31). SeisWare displays the faults in the Faults Selected field of the Fault Assignment window.

Figure 31: Basemap – Choosing Faults to Reassign

 Create a New Fault with a unique color in the Assign To section and set the Type.  Click , and SeisWare now reassigns the fault to the new name. Note the changes to the Basemap, Seismic Viewer and the 3D Visualizer.

Triangulating Faults To create a full planar surface from the picked segments, use the triangulation feature. This will take the picked segments and using a simple triangulation process, create a full surface. This surface can then be displayed in the 3D Seismic Visualizer, and


40


the intersection of that surface will appear in your Seismic Viewer as a dashed line. Although similar looking to the projection, this is where the calculated planar surface exists. When you triangulate your faults, only the currently picked segments are used in the triangulation. If you wish to keep adding segments, you can leave the Fault Triangulation window open as you pick and keep updating the triangulated surface. You can also completely remove the triangulated surface by deleting the triangles from Fault Properties. Simply right click on the fault, and select Delete Triangles from the menu that appears. The triangulated surface can also be used in other fault tools such as the Contour Fault feature in the next section. When you are generating fault planes, try to pick segments only in one direction, preferably the dip direction. This will create the best results from the triangulation algorithm. SeisWare displays the triangulated plane in the strike direction, with symbols for the intersected segments.

Exercise  To create a triangulated surface from fault segments, go to Fault  Triangulate Faults either on the Main Launcher, or on the Seismic Viewer. This will open the Triangulate Faults window (see Figure 32).



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Figure 32: Triangulate Faults Window

 Select the Fault APWG (see Figure 33), and click

Figure 33: Seismic Viewer – Triangulated Faults

 In the 3D Seismic Visualizer, ensure that Show Triangle Edges is not checked in the Faults Properties section of the General 3D Visualizer Properties, and ensure that Show triangulated surface is turned on. You can check the faults as


42


planes (see Figure 34), or as edges (see Figure 35) in the 3D Visualizer.

Figure 34: 3D Visualizer – Fault Triangulation Planes

Figure 35: 3D Visualizer – Fault Triangulation Edges

 From the Main Launcher’s Fault menu and choose Properties.



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 Highlight the fault “AWPG” and, from the Edit menu, choose Delete Triangles.

Contouring Fault Surfaces When a fault has been triangulated you can contour the fault to better visualize the 3D surface. The contours are displayed on the map and can be used to check the triangulation. You can also color the surface using the Fault to Horizon feature described in the next section.

Exercise 1. Create contour  From the Main Launcher’s Fault menu select Triangulate Faults.  Click and to ensure that all faults have been re-triangulated.  Open the Grid and Contour window (use the icon).  Select Contour Fault and press

.

 Select “APWG” from the list of existing faults and press

.

 By default the contour layer will be given the name of the fault followed by “Fault Contour”. Leave the Contour Name as the default.  Press Compute Data Range to help to determine the contour intervals in the next step, and press .


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 Enter a Regular Contours Interval of “50” and a Thick Contours Interval of “100”.  Enter a Labelling Interval of “100” and leave everything else as the default.  Enter a Distance Between Labels of “500” and a Labelling Size of “0.25” Fixed Size (Inches).  Press

then

.

2. Display contour  Right click on the Basemap and select Layer Properties.  Turn on “APWG Contour” from the list of available contours.

Converting Faults to Horizon If you wish to see color with the contoured fault, or if you need your fault surface represented by a horizon, you can use the Fault to Horizon functionality. This will take either the individual segments or the triangulated fault surface and create a horizon. The default name of the horizon is the name of the fault followed by “_Fault”. Please note that when this process is run some data may be lost because, unlike faults, horizons do not support multiple z-values on a trace.

Exercise  From the Main Launcher’s Fault menu select Fault to Horizon. SeisWare opens the Fault to Horizon Window (see Figure 36). 

From the list of available faults select “APWG”.



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 Select “Use Fault Triangles” from the Input Parameters.

Figure 36: Fault to Horizon Window

 Leave the Name as the default and toggle on Make horizon visible.  Press

.

 From the Horizon to Ribbon dropdown select "APWG_Fault". The horizon can be viewed in both the Seismic Viewer and the 3D Visualizer.

Generating Fault Polygons After you pick a horizon through your faults and create fault/horizon contacts, you can generate fault polygons to use in mapping. SeisWare will use the contacts that exist and connect them to create either a fault line or fault polygon. By default the color of these polygons will be the color of the fault they represent.


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There is an automatic extend feature that allows you to set a distance to which the fault will be tapered out. This is very useful and helps minimize editing later on. When the fault polygons are created, they are considered culture objects, and can be edited using the Culture Editor on the Basemap. You will be able to see the nodes used for generation and change the shape if you wish to add more character to the polygon. Generating the polygon without a fill or with a hatched instead of solid fill makes it easier to edit the polygons after generation. To modify parameters such as the line style and colors, you can change the layer properties from Culture Properties. From the Culture Properties window, double click on the layer to access the Change Layer Properties feature. The fault polygons can be used in the Grid and Contour Fault Polygons section and will be used to define areas across which there should be a discontinuity.

Exercise  Use the Main Launcher’s Fault menu and choose Polygons/Contacts. SeisWare opens the Fault Polygons/Contacts window (see Figure 37).



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Figure 37: Fault Polygons/Contacts Window

 Select the “APWG” fault, the “Grabben” horizon, and the “nsask” 3D.  Click . SeisWare should create a polygon named “Grabben Polygons”, and displays these on the Basemap (see Figure 38).


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Figure 38: Basemap – Fault Polygons



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WELL PLANNING SeisWare allows you to create and modify well plans using the Well Planning tool (see Figure 39). The Well Planning tool is linked with multiple applications so that you can create or modify a well plan from the Basemap, the Seismic Viewer, the 3D Seismic Visualizer, or by directly entering values into the table of the Well Planning dialog.

Figure 39: Well Planning Dialog

When wells are created with respect to a time volume they can be converted to depth using an existing velocity curve. The wells that are planned can be exported to a columnar ASCII file, or saved to the SeisWare well database and accessible from well properties.

Creating a new well plan To create a new well plan, you can use the: Basemap, Seismic Viewer, 3D Seismic Visualizer or the Well Plan Dialog tool. The dialog can be opened in multiple ways. From the Main Launcher you can select Well Planning from the Well menu. If you open the dialog using this method you can then manually enter the values into the dialog.


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When the Well Plan dialog opens you can begin making the plan. Add a new row to the dialog by using the

button. After

each entry has been added you then hit Enter on your keyboard to save the row entry. Repeat the process to complete the well plan. The rows can be reordered by selecting the row, then using the up and down icons. The rows can be deleted using the icon. You can also launch the Well Plan dialog by clicking on the Well Planning icon (

) found on the Basemap, in the Seismic

Viewer, or in the 3D Seismic Visualizer. After clicking on the icon you can start visually planning the well with a series of mouse clicks. Before you begin the plan you must ensure that the Datum Elevation field at the top of the dialog has been fill in correctly. This value will be used to convert values between TVD and Subsea. As the table fills up, this value will be automatically used in the calculations. Once you have created a plan, and the table has been filled in, the plan can be edited from the Seismic Viewer, Basemap, or 3D Seismic Visualizer window.

Adding a Node Nodes can be added with a series of left mouse button clicks. If nodes have been added in an incorrect order you can reposition the node using the up and down arrows in the Well Planning dialog. As you click to make your plan the X and Y fields in the dialog will populate. If you are selecting nodes from the Basemap then no Time or Depth fields will be populated. To add values to these fields you



must extract values from an existing horizon. This functionality can be accessed by selecting Load Time/Depths via Horizon from the File menu of the Well Plan dialog. When you are planning the well in the Seismic Viewer, or in the 3D Seismic Visualizer, the time fields will populate when picking on a time volume, and depth fields when picking on a depth volume. Using an existing velocity curve will allow you to convert time plans into depth. This functionality can be accessed from the File menu and selecting Convert Time to Depth using Velocity Curve. Note that this does not work in reverse and will not convert from depth to time. When designing a plan in the 3D Seismic Visualizer, the nodes will snap to the display inline/crossline/time slice, so ensure that the desired slices are displayed.

Repositioning a Node If a node has been placed incorrectly you can left click on the node square, hold down the mouse button, and drag the node to a new position. The values should update in the Well Planning dialog. If you prefer, you can type directly in the Well Planning dialog to change any of the parameters for a node. When moving nodes in the 3D Seismic Visualizer, make sure that you use the status bar to track your position, as you can move in the inline, crossline or time/depth direction.

Deleting a Node To delete a node, left click on the node. Once it highlights hit Delete on your keyboard. Alternatively, after the node is


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highlighted, you can use the

icon in the Well Planning

dialog.

Completing a Well Plan Right click to add the last node and stop the well planning mode. The Well Planning Dialog will remain open, however edits will no longer be allowed from the application that you are in. After a plan has been created it can be saved as a well, or as a file. Either option can be opened from the File menu.

Loading an Existing Well The well planning tool allows you to open an existing directional survey for editing. Select Load Well from the File menu, and when prompted select the well. After the table populates you must first check that the Elevation field is changed to the correct elevation so that the subsea values are calculated properly. You can now modify any of the values, either manually in the table, or by visually editing the nodes using the Seismic Viewer, Basemap or 3D Seismic Visualizer. Save the changes by selecting Save Well from the File menu.

Exercise  Open your 3D Seismic Visualizer, and load the “nsask” 3D volume into the display.  From the Basemap, Launch inline 128 in the 3D volume “nsask”.



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 In the Seismic Viewer, click on the Well Planning icon ( ). This will launch the Well Plan Dialog (see Figure 39)  In the Well Plan dialog, type in an Elevation of 1800 feet.  Left click in the Seismic Viewer to add a point.  Keep left clicking to add points to the well plan. Right click once to end editing (see Figure 40)

Figure 40: Well Plan in the Seismic Viewer

 Go to a node on the Seismic Viewer, left click, hold and drag to reposition.  Click between nodes to add a new node that can be used to adjust the well plan.  In the Seismic Viewer, click on the Well Planning icon (


) to stop editing.

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 On the Basemap, click on the Well Planning icon (

).

 Hover your cursor over an existing node point until your cursor becomes an arrow with a circle ( ). Click and drag to reposition a node (see Figure 41)

Figure 41: Editing nodes on the Basemap

 On the Basemap, click on the Well Planning icon (

) to stop editing.

 In the 3D Seismic Visualizer, click on the Well Planning icon (

).

 All of the nodes should appear as green spheres that can be repositioned by clicking and dragging (see Figure 42).



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Figure 42: Editing nodes in the 3D Seismic Visualizer



Move the node off the inline and it will disappear from the Seismic Viewer display.

 In the 3D Seismic Visualizer, click on the Well Planning icon to stop editing.  From the File menu select Convert Time to Depth via Velocity Curve.  Select well “100232” and click

.

 From the File menu select Save Well.  Type in the name “Planned Well” and leave the check mark on for Output velocity curve and click . The new well “Planned Well” is now a part of your project.


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TIME TO DEPTH CONVERSION SeisWare provides a wizard-based approach to depth conversion. The approach is limited to vertical techniques, from a simple constant velocity to more complex methods which use average interval velocity. You are given full control over the input data, the gridding parameters used, and are also given the opportunity to preview the results in case any adjustments need to be made to your choices. All depth grids will be created in Sub Sea.

Figure 43: Choose Time/Depth Method Window

Selecting Time to Depth Method There are six Time to Depth Methods to choose from.



Constant Velocity Method This method uses a time grid and multiplies it by a constant velocity to create a depth grid.

Average Velocity Method This method is commonly used. It incorporates wells tops and seismic, thereby allowing lateral velocity variation. The principle is to relate a horizon to a specific formation top, providing both time and depth measurements at the well location. First the time grid is created using the time horizon, or an existing horizon grid. At each well location an average velocity spot is created using the horizon time and the top depth. The velocities are then gridded, making a velocity grid. The time grid and velocity grid are used to produce a depth grid.

Interval Velocity (Layer Cake Method) With this method you can account for velocity and thickness variations in the sediments overlying the depth-conversion target. This method is similar to the Average Velocity Method however rather than working with a single horizon-top equivalence you work with multiple intervals (see Figure 44).


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Figure 44: Time to Depth Interval Velocity

A time grid is produced for each horizon, and the time values are extracted at each well location. Using the average velocity method described above the shallowest depth grid is created. For each successive entry in the equivalence table, an isopach is calculated from the well tops, and isochrons from the well–grid intersection of the time grids. The average interval velocity value is calculated at each well, then gridded and multiplied by the isochron grid to produce an isopach grid. This is then added to shallowest depth horizon to create the depth-converted surface. The Interval Velocity Geologically Controlled technique follows the same algorithm as above, except that the first layer is calculated directly from well tops, and does not take the first horizon into account. When working with Interval Velocity method you can optionally output velocity curves at the well locations. This technique is helpful for tying wells that have no digital curves for generating



synthetics. SeisWare uses a time–depth pair for each equivalence to create a generalized velocity function, which is more accurate than copying a velocity curve from another well.

Velocity Curve: Time to Depth Method With this method, the program depth-converts time horizons using velocity curves at well locations. These can be edited velocity curves created by stretching and squeezing synthetics, or velocity curves generated during an interval velocity run. An advantage of this method is that you can depth-convert horizons that might not have tops within a constrained velocity model. You need to pick a Horizon to Convert and which Velocity Curves to use.

Velocity Curve: Depth to Time Method This method operates similarly to the velocity curve time to depth method. In this case, you select a top and use it to create a time horizon based on velocity curves. You can also pick multiple tops and use the interval velocity method. This is useful when you have a top that does not correspond to an identifiable seismic response.

Creating a Depth Grid When creating a depth grid the Time to Depth wizard makes it easy to configure for the best output.


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60


Select Method This page of the Time to Depth wizard allows you to select the technique you wish to use.

Exercise  From the Select Method step, select Interval Velocity and click Next

Interval Velocity When setting up the interval velocity method, you need to create equivalences. These are the paired association between a time horizon and the well formation top that represents that horizon. You will typically be using a picked horizon from your project and loaded tops, but you also have the option to use an existing grid. This may be advantageous if you have edited the time grid. You can also use an existing velocity grid instead of selecting tops. The Output Name specified will be used to generate the depth grid result for the layer specified. To set the equivalences for multiple layers use the arrows (

) at the top of the dialog to go to another equivalence

page. Look out for red exclamation marks (

) that mean some

information may be missing.



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Exercise  In the Interval Velocity window, Time Options ensure Generate from horizon is selected and pick the horizon “Heebner_Shale AP” from the dropdown list.  In Velocity Options select Generate from tops.  Click on to open the Select Tops window (see Figure 45).  Move “Heebner_Shale” to the Selected Tops side and click

..

Figure 45: Select Tops Window

 Click the

sign to add another equivalence.

 Set up the following horizon and top equivalences: Lansing AP – Lansing


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Miss – Miss  When you have all three equivalences, click .

Gridding and Bounds Options This page allows you to set the gridding options that will be used. With the equivalence information entered, the wizard will create a time and velocity grid. For both of these grids, you can set the gridding algorithm. The algorithm specified along with bin size is data dependent and should be determined by you. The Apply residual adjustment option will try and flex the final depth grid to the value of the tops specified. When this isn`t used there may be a discrepancy between the output grid depths and the original top depths. The Velocity Scale Factor can be used to smooth out your velocity grid by increasing the size of the bins used. The size of the output grid can be determined to the Restrict Bounds To options. These work in conjunction with the data that is selected, as well as any polygons selected on the Polygon Control page. You can constrain the output grid to the data that you have by a combination of the wells and seismic, to an already existing grid, or to user defined extents which are set by dragging out an area on the Basemap



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Figure 46: Grid Parameters Window

Exercise  Select Minimum Curvature for the Time Grid Technique.  Select Minimum Curvature for the Velocity Grid Technique.  Enter a Bin Size (in map units) of “50” (feet).  In the Restrict Bounds To section, select Seismic and Use 3D seismic and click proceed to the Output Options step.

or

Output Options This page allows you to select from several options that may help you check the results from the time to depth operation. You can generate simple velocity curves, and output additional grids


64


and tops. This way all intermediate calculations are seen either in a grid or in the well properties. It`s useful to keep both the time and the velocity grids so that you have a record of the velocities that were used to produce your depth results. If you don`t want to generate any additional data you will also have the option to see all intermediate results in a spread sheet format at the end of the procedure. The Output Options page also allows you to specify the properties for any contours generated while generating grids. SeisWare will automatically determine contouring intervals, so it may be easier to generate the grids without contours at the start and then generate them using the Grid and Contour dialog later when you are happy with the final output.

Exercise  Select Attach time grids and Attach velocity grids.  Click on Contour Grids.  For Smoothing, click on Using Spline. 

Click on the Label Contours option and change the size to “500” Variable meters.

 Click

.

Select Data Options The following pages all let you restrict the data input into the Time to Depth algorithm. The data items included are Top Sources, Wells, Seismic and Polygons. You can restrict by selecting items off the list or by dragging out the area on the



65

Basemap. Polygons can also be set to restrict the gridding if so desired.

Exercise  Select all Sources.  Click

and select all wells.

 Click

and select “N3D”.

 Click set.

and make sure no polygons are

 Finally click and then the button to see your output grids.

Output Grids Once the time to depth conversion has been completed, you should see a series of Time, Velocity and Depth grids displayed in the Output window (see Figure 47). The default color bar used for displaying the grids can be changed in the Color Bar dropdown. The color bar will apply to all grids. Due to sparse well data the velocity grid may not look as expected. To check the values that were used to generate any of these velocity grids, use the Well Point button to the left of the series of grids. This is a table of the values used to generate the grids at the well locations. This file can be saved if desired. If you are happy with your output you can press Close to exit the dialog. Your grids will now be available in the Grid to Ribbon dropdown on the Basemap. If you need to add control points to


66


the velocity grid, or if you want to remove any velocity anomalies from the velocity grid, you can press

.

Figure 47: Output grid

Editing Velocity Grids The velocity grid often needs to be edited. Points may need to be added to correct and refine the grid. This can be done by clicking the Edit button to the upper right of the velocity grid preview. When the editing window opens you will see a list of all of the velocity points used to create the grid. Clicking on a point on the grid will highlight the velocity value. If a row is selected in the list then the corresponding point will highlight on the preview grid. To delete a point simply click on the well symbol on the grid, or select the row in the table and click the Delete icon (

).



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When adding points, you have the option of using a velocity value (

), or a sub sea depth value (

). If you select a

depth value, you can enter a value manually, or you can extract the depth value from a grid at a specific well location. Using the Regrid icon (

) will show you a preview of the grid with

changes reflected. If you are manually added velocity point, you may save the velocity points (

). This will allow you to maintain a record of

the point you added to correct the grid, without have to add permanent control point or “fake wells” into your project. These can also be loaded (

) if you rerun the time do depth

calculation. When you close out of the editor, all of the other grids in the conversion will be recalculated based on the new velocity grid. The get rid of edits, use the Reset Values button on the Output Grids page and click Finish to re-run.

Exercise

 Click the Edit button beside Velocity grid in the“Heebner_Shale AP row. This will open the Heebner_Shale AP velocity grid.  Click and drag the left mouse button to draw a box over one or more points you feel are incorrect.  Click the

button to delete these points.

 Hit the Add Velocity Point icon ( ) and then click on a location on the velocity grid where you would like to add a point. This will add a new entry to the


68


bottom of the Z, X, Y, UWI spreadsheet to the right. Type in the desired velocity ( Z ) value in this chart and hit the Enter key on your keyboard.  Click on the grid icon ( ) to see how your changes have affected the velocity grid (it will be recreated).  Close the edit window to recompute the depth grid with the new velocity grid.  Close the Time to Depth window and look at the grids on the Basemap.



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LOG EDITOR All log information that has been loaded into SeisWare can be edited using the Log Editor. You can remove spikes from the logs, splice logs together, shorten logs, and perform simple modeling using log edits. The Log Editor can be opened by choosing Log Editor from the Main Launcher’s Well menu. You can also right click on a well symbol on the Basemap and choose Log Editor from the menu. SeisWare displays the Log Editor window. When the Log Editor is opened for the first time the default view will use the template for “Default Geophysical Automatic” and will contain a Time/Depth track, Tops track and tracks for GR, DT and RHOB. More templates can be loaded, and new templates can be saved from the File menu. By default only wells with curve information will be displayed in the well list; however these can be further limited by selecting a pre-existing well list from the Show Well List dropdown. To select a well from the Basemap, Seismic Viewer or Well Properties, make sure that listening is turned on (

) then

click on the well symbol or name. After a well has been selected you can start performing edits of the curve and top information, saving the changes as you work.

Navigating in the Log Editor By default, when a well is selected, the entire log curve will be displayed. Use the zooming tools to position and center yourself on areas of interest. These are found on the Zoom Toolbar (see Figure 48).


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Figure 48: Zoom Toolbar

The following is a list of zoom options: Fit Data ( ): fits the full extents of the longest curve into the track view. Vertical Zoom ( ): click then left click and drag out an area to zoom in on. The horizontal scale will not change. Zoom In ( ): click then drag out a rectangular area on any curve. All curves will zoom vertically and the selected curve will zoom horizontally. Previous Zoom (

): restores the previous zoom.

Define Home Location ( ): define a position using a range of depths, between tops, centered on a top, or using a range of times. Goto Home Location ( as defined above.

): returns the view to the location

Displaying Curves When you first open a Log Editor the display will be blank until you select a well. After that you can add additional wells, and velocity curves.

Displaying a Log Curve Beneath the list of available wells is a list of available curves. Once a well has been selected, you can add any of these curves to a track by dragging it from the list and dropping it into the desired track. If you would rather display the curve in a new



71

track you can use the Add Track icon (

). You can then select

the name of an existing curve from the Use curve name dropdown or Use Curve Alias field (see Figure 49).

Figure 49: Select Curve Alias Window

Displaying a Synthetic Track You can generate synthetic tracks by clicking the Generate Synthetic Track icon (

). These can be created using the

same wavelet parameters found in the Seismic Viewer Generate Synthetic Track dialog.

Displaying a Velocity Curve You can view the active velocity curve, using the Add Velocity Curve Track icon (

).

A note on Aliasing Aliasing allows you to use wildcard characters to broaden the number of curves that you can view when your naming


72


conventions are non-standard. For example you may have DT curves named “DT”, “DT1”, “DT4” etc. You could type in the curve alias “DT*”, using the wildcard symbol “*” to include all curves. If more than one “DT*” curves exists the last curve listed will display. Curve aliases also apply when generating synthetics.

Exercise  Highlight well “10003” in the Show Well List field (see Figure 50).

Figure 50: Log Editor Window

 Experiment with the zoom options found on the Zoom toolbar then click the Fit Data(

) icon.



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 Click the Add Track icon ( ). The Select Curve Alias window opens (see Figure 51).

Figure 51: Select Curve Alias Window

 Select the “SPOR” (Sonic Porosity) curve from the list. SeisWare adds a track with the curve information displayed in black.  Select any curve from the Log Curves list and drag in onto the SPOR track. You will now see both curves displayed on the track, and both curves listed in the title bar of the track.  Place your cursor on the title bar of the track, then left click and drag the track to a new position (see Figure 52).


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Figure 52: Moving Tracks

 Right mouse click on the SPOR track and select Delete Track.  Click on the Add Synthetic Track icon (  Click on the Add Curve Alias icon ( Sonic curve.

).

) to select the

 Select “DT” from the Select Curve Alias Name dropdown.  Select the “RHOB” curve for the Density curve in same manner as the Sonic.  Leave the other options at their defaults settings (see Figure 53).



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Figure 53: Synthetic Properties Selection

 Click . A synthetic track will be added to the display (see Figure 54).


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Figure 54: Synthetic Track

 Click the Add Velocity Curve icon ( ). This adds the active velocity curve to the display.

Setting up Log Editor Properties The Log Editor properties allow you to select default colors, scales, units, opacities, and tops properties. There are different properties that are used for the main Log Editor settings, the curve tracks and the synthetic tracks.

General Track Properties The General Track Properties, which control the main window display, are accessed using the General Properties icon (

).

From here you can control, among other things, the curve



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selection color, Log Editor units, horizontal grid lines and displayed tops. Any changes applied here are applied to the log editor window. These will become the default settings once they are applied.

Track Properties Properties can also be controlled for each individual track. They are accessed by right clicking on the track and selecting Track Properties. For any curve track you can control displayed curves, curve aliases, curve colors, data range, vertical grid lines, opacity and fills. For synthetic tracks, you can see the synthetic generation parameters used initially when the track was added, and modify if needed.

Exercise  Click the General Properties icon ( ) to open the General Track Properties window (see Figure 55).


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Figure 55: General Track Properties

 Change the major grid lines color from green to orange and click . SeisWare now displays the grid lines in orange.  Repeat these steps, but change the major grid line color back to green.  Adjust the Opacity of the Tops and click  Click window.

.

to close the Log Editor Properties

 Right mouse button click on the GR(LAS) track and select Track Properties (see Figure 56).



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Figure 56: Individual Track Properties

 Change the Scales selection to Set Range and enter a Right value of “275”. Click

.

 Change the major Grid Lines Increment to “100” and the minor Increment to “50”. Click  Click the Fill Properties tab (see Figure 57).


.

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Figure 57: Track Properties – Fill Properties

 Change the Fill Type to Use single color, place a checkmark in Above value and change the color to yellow. Click . Above Value will fill the curve from the Reference Value to the curve. Below Value will place fill from the curve to the Reference Value (see Figure 58).

Figure 58: Fill Above Value and Fill Below Value



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 Select a Fill Type of Use color based on curve and select the “GR” curve by clicking the Add Curve Alias icon (

). Click

.

 Select Save Template from the File menu. Give the template a name so that it can be used later on.

Editing Curves When you select a curve to edit, SeisWare activates all of the curve editing icons (see Figure 59) at the top of the Log Editor window. These tools are used to modify the highlighted curve. While editing, the changed curve will be shown in the highlight color, by default red, but the original unedited curve will show in its original color. This way you can see both your edited and unedited curves at the same time. If you are trying to modify a curve to see the effect on a synthetic, use the undo and redo icons to quickly see how the last edit will change the synthetic. After editing curves, use the Save icon (

) to save changes

made. If you have edited more than one curve, you will be prompted with the original name of each curve and you should change either the name or the source so you don’t overwrite your original curve.

Figure 59: Edit Curve Icons

Some of the edit options are: Draw on curve in freehand ( ): click on the curve, hold down the mouse, and freehand draw the desired edits.


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Draw on curve in straight line ( ): click and drag the mouse over a section of the curve. SeisWare draws a straight line to connect the start and end points of the section. Zap ( ): Sets a curve to a constant value. Move the mouse onto the curve. SeisWare draws a straight yellow line, as in the diagram at the right, at the value of the mouse, extending from the intersection points between the actual curves (above and below the mouse) and this value. Right click on the mouse to set the curve to the constant value between those two points. Straight line between two points ( ): left click on the first point and drag the cursor to the second point. SeisWare draws a straight line between the points. Shift curve up or down ( ): click and drag the curve up or down to set a new starting point. This will not change the scale of the data. Clip curve above value ( ): click and drag the mouse to highlight the data to be clipped. Everything in the highlighted section will be assigned the clip value. Clip curve below value ( ): click and drag the mouse to highlight the data to be clipped. Everything in the highlighted section will be assigned the clip value. Crop data from the top ( the curve.

): deletes data from the top of

Crop data from the bottom ( bottom of the curve.

): deletes data from the

The following options require that a range of data is first selected by using the Select portion of curve icon (

) then

using your left mouse button to select a portion of the curve, or manually entering extents.



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Average a range of data ( ): opens the Kernel Size For Averaging window. Set the filter size for averaging, then click and drag a range of the curve that you want to average. SeisWare applies that filter to that area of the curve to average it. The larger the kernel size, the more averaging that SeisWare applies. Block a range of data ( ): opens the Kernel Size For Blocking window. Set the number of blocks, then click and drag a range of the curve that you want to block. SeisWare breaks that range of the curve into the number of blocks that you specified. Scale a range of data ( ): drag the mouse over a depth range to highlight a section of the curve. As you move the mouse to the left or right, that section of the curve is scaled up or down. Shift curve left or right ( ): click and drag the mouse over the section of the curve you want to shift. Move the mouse left or right to shift the selected section then click again to complete the shift. As you edit the curves you will see an image of the original curve displayed in the track. The properties of this image are controlled with the Original Curve Opacity slider located in Log Editor Properties. To exit a specific editing mode click the Stop icon (

) or use

the Esc key on your keyboard. To stop editing a curve, select Stop Editing from the right mouse button menu.


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Exercise  Left click on the DT curve in the first track to select it for editing. SeisWare highlights the DT curve in red to indicate that it is the active curve and that you can edit it.

Figure 60: DT Sonic Curve Selected for Editing

 Work through a series of edits to see what effect each has on the synthetics. After each edit, undo the edit ( ) so that you start with the original sonic log each time.  Click on the diskette icon ( ) at the upper left of the Log Editor, or choose Save Curve from the right mouse button menu. SeisWare opens the Save Curve window (see Figure 61).



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Figure 61: Save Curve Dialog

 Enter a new curve name to create a new curve, or select an existing curve name and SeisWare overwrites that curve.

Editing and Adding Tops The Log Editor has a tops track that displays the tops at the appropriate depths. You can use your logs for visually checking these tops, and editing or adding new tops. When in the Editing Tops mode, you will see a toolbar appear at the top of the Log Editor (see Figure 62). There is tracking at the bottom of the Log Editor on the status bar for helping with positioning.

Figure 62: Editing Tops Toolbar

Exercise  Click and left click on the “Howard” top. The cursor will now look like an arrow with a green line (


)

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 Move the cursor and left click in the new top location. The moved top will be saved with the information displayed in the toolbar.  Click the  Click

button to save the top. .

 Select a Formation from the dropdown, and then click on the log track where you want the formation.  Select a source from the Source drop-down list.  Click the

button to save the top.



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2D MODELING/CROSS SECTION SeisWare’s Cross Section and 2D Modeling functionality allows you to create a simple 2D Cross section using existing tops and depth grid information in your project. After creating the correlations between wells, you can generate synthetics at the well locations and then use the synthetics to generate a simple 2D Seismic Model. This model can be saved as a SEG-Y file and can be used within your SeisWare project.

Selecting Wells for the Cross Section: Wells can be selected from the Basemap, or from the Cross Section dialog.

Selecting wells from the Basemap Use the Select Cross Section icon (

) from the Basemap's

Well Toolbar, and then left click to select the wells. Right click stops selecting and launches the Cross Section dialog.

Selecting wells from the Cross Section dialog From the File menu select Select Wells. Select the wells you want included in the cross section. Any wells selected will be displayed in the order listed. To re-order a well, highlight it from the list and use the up and down arrows ( the well on the list.


) to reposition

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Setting up 2D Modeling/Cross Section Properties There are several different property settings for controlling the appearance of your cross section and model.

Cross Section Properties These properties control the spacing for your cross section, basic flattening and fill options. To access these properties, use the icon (

), or select Cross Section Properties from the

Edit menu (see Figure 63). Properties can be saved and loaded using the Save Properties and Load Properties options from the File menu.

Figure 63: Cross Section Properties

General Track Properties Set the properties for all tracks by selecting the Track Properties icon (

), or selecting General Track Properties from the Edit



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menu (see Figure 64). Control the track colors, grid lines, units, tops appearance and scaling.

Figure 64: General Track Properties

Track Properties Track properties is used to customize an individual log, synthetic or velocity track at each well location. To access these properties for any track, right click on the track and select Track Properties (see Figure 65). These settings are the same as the Log Editor settings and an existing template can be opened by selecting Load Log Template from the File menu.


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Figure 65: Track Properties

Once the track properties have been set up you can save the display as a template. Right click on the well name and select Save Log Template. When a template has been created you can quickly update all wells with identical settings. Right click on the well name and select Apply Log Template. These templates for the track properties are the same as the ones in the Log Editor and can be used interchangeably.

Model Properties Model Properties controls the spacing, and well bore appearance. Access the Model Properties using the icon in the Model window

or selecting Model Properties from the Edit

menu of the Cross Section window (see Figure 66).



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Figure 66: Model Properties

Adding Tracks Tracks can be added using the Track Toolbar. Items that can be added are log curves, velocity curves and synthetics. You will need to generate synthetics for your wells in order to generate a 2D Model. The display and set up of the tracks is similar to that of the Log Editor and Log Editor templates can be used in this application to load in your already saved settings from the Log Editor.

Adding a Log Curve Click on the Add Track icon (

). This will open the Select

Curve Alias dialog. Select the curve name and click OK. To modify the appearance, access the Track Properties by right clicking on the track, and selecting Track Properties.


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Adding a Synthetic Click on the Add Synthetic Track icon (

). This will open the

Synthetic Properties dialog that allows you to set up the synthetic as desired. To modify the appearance, access the Track Properties by right clicking on the synthetic, and selecting Track Properties.

Adding a Velocity Curve Click on the Add Velocity Curve Track icon (

). The current

Active velocity curve will automatically be placed in the track. To modify the appearance, access the Velocity Track Properties by right clicking on the track, and selecting Track Properties.

Exercise  On the Basemap, click on the Cross Section icon (

).

 Select the wells by left clicking: 100464, 100439, 100177, 100003 as shown in Figure 67. Right click to end selection and launch the Cross Section dialog.



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Figure 67: Well Selection from Basemap

 Click on Select Wells in the File menu of the Cross Section dialog.  Click on well 100003, and use the take it off the list of Displayed Wells.  Click

button to

to close the dialog.

 In the Cross Section window, click on the Cross Section properties icon (

).

 Check on Fill behind log templates  Click

to close the dialog.

 In the Cross Section window, right click on the DT(LAS) track, and select Track Properties.  Change the Curve Color from to blue, and click

 In the Cross Section window, right click on the UWI above the track changed, and select Apply Log


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Template(see Figure 68). All of the other wells should now have the same parameters.

Figure 68: Apply Log Template

Adding and Editing Correlations: To create a cross section you need to add correlations between tops. After the correlations have been added there are additional options to customize how the correlations behave between wells. By default the correlations will exist as straight lines between existing tops.



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Adding a Correlation Use the Add/Edit correlations icon (

) to launch the

Correlations window (see Figure 69). From here you can select an individual formation manually using the

button. If you

have a tops list already created, you can use the Generate from Tops List option.

Figure 69: Correlations Window

Once the correlation is added, select the correlation and customize the display settings using the options on the left hand side of the Correlations dialog.

Using Depth Grids If a depth grid is available for a formation, it can be applied to the correlation. This will adjust points along the correlation


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between wells so that it corresponds to the depth grid. Use the Depth Grid dropdown field in the Correlations dialog.

Adding points After the correlation line has been added to the cross section, use the Add/Move point icon

to go into the Add/Move Point

mode. This will allow you to add a point along the correlation and then allow you to move that point so that you can customize the correlation between the wells. Left click to insert a node point and then move the points by left clicking and holding down and dragging to reposition.

Editing Correlations and Updating Formation Top Values Once the tops have been correlated, you can edit the end point of a correlation and use this to update the top value. Use the Add/Edit correlations icon (

) to launch the Correlations

window. Make sure that the formation is selected in the Correlation dialog. This should make the correlation line highlight with a red color. You will now be able to click the end points and drag them to the desired position. To save the changes select Save Tops from the File menu. The current depth of the end point will be saved as a new top. Note that this does not overwrite the old top, but adds a new top with a different depth in the database.

Deleting Correlations To remove a correlation, use the Delete Correlation icon (

)

from the toolbar. Once selected, any correlation that you click on will be removed.



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Adding Correlations for Tops that Don’t Exist If you want to add a correlation for a top that does not exist, from the Correlation dialog, use the

button and select New

Correlation. Give the correlation a name and work with it as a normal top. Once it has been added to the cross section, you will be able to reposition it using the Add/Move Points icon ( ). If you want to save the changes select Save Tops from the File menu. The current depth of the end point will be saved as a new top with the name specified as the Correlation name.

Exercise  Click on the Add/Edit Correlations icon (

).

 Click on the button to launch the Add New Correlation dialog.  Select the “Heebner_Shale”, “Lansing”, “Miss” and “Stark_Shale” formations and click

.

 Select the “Heeber_Shale” formation on the left of the Correlations dialog.  Change the Fill Type to “Both”, the Color to green, and the Fill Pattern to “Shale”. The Cross Section should update.  Repeat the process for the “Lansing” and “Stark_Shale” formations, using different colors and fill types.  Click

.

 Click on the Add/Move point icon (


).

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 Hover your cursor over a correlation and click to insert a point.  Click and drag the point to reposition (see Figure 70).  Click the Stop button

to complete editing.

Figure 70: Cross Section with correlations, being edited

Creating and Saving 2D Models To generate a 2D model from the cross section, a synthetic track must first be added to the Cross Section display. This synthetic will be used to generate the model. To generate the model, use the Display Model icon (

) from the toolbar. This

will launch the model window. To customize the display, use the



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Model Properties that can be accessed by the icon (

) in the

Model dialog or from the Edit menu in the Cross Section dialog.

Saving your Model: Once a model has been created it can be saved as a 2D SEG-Y file. To do so, click on the Save Model icon (

) in the Model

window. This launches the Output 2D SEG-Y dialog that allows you to create a SEG-Y seismic file (see Figure 71). There is also the option to create a segment file.

Figure 71: Output 2D SEG-Y Dialog

Saving Cross Sections After any work has been done in the cross sectioning dialog, you can save the display and revert back to it at a later time. To save the entire cross section select Save Cross Section from the File menu or click the Save icon (

).The properties are

saved to an .xml file. To re-display a saved cross section select Load Cross Section from the File menu and select the “.xml” file. You can also reload the last created cross section by loading in the "LastCrossSection.xml" file.


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Exercise  Click on the Display Model icon (

).

Figure 72: Generated Model

 Click on the Model Properties icon (

.)

 Check on Fill Correlations on Model.  Click

.

 Click on the Save Model icon (

).

 Give the output 2D Line a File Description “Zone between Heebner_Shale and Miss”  Check on Output Segment File.  Select “N3D” from the list.



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Figure 73: Saving the Model

 Click . You will now see a 2D line on your Basemap that represents the seismic model.  Close the model window by clicking on the

.

 Select Save Cross Section from the File menu of the cross section window.  In the File Name field, give the cross section a name.  Click


.

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HORIZON SMOOTHING AND COMPUTING ATTRIBUTES You can either smooth horizons or compute attributes with SeisWare’s Horizon Smoothing/Attributes functionality.

Creating Smoothed Horizons When smoothing a horizon, there are different methods for smoothing. There are options for what values get smoothed, and how far away from starting bins the smoothing will extend. Depending on your data set and desired result, the parameters will need to be modified. The smoothing options are: Smoothing: average the values in the defined grid Weighted Smoothing: weight the averaging from the centre bins toward the outer edges of the grid Median Smoothing: compute the median value of the grid for the output The parameters for the smoothing operation are: Inline Grid Size: set the number of picks to use for the smoothing. It must be an odd number because the grid is centered on the input pick. Crossline Grid Size: the number of picks to use in the crossline direction of the 3D; only applicable for 3D horizons Apply Inline vs. Crossline Bin Size Correction: apply a correction to compensate for any inline versus crossline differences in the 3D bin cell size; only applicable if the 3D bin size is different in the inline versus crossline directions



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Smoothing Parameters: used to determine what gets smoothed. Operate on asks what values should be smoothed i.e. data values or null values or both. If you wish to preserve your original picks, just use null values. When smoothing into areas where there are null values, specify if the smoothing should just fill holes (i.e. areas where there are picks surrounding those traces) or expand edges. If no fill distance is set, the fill will extend to completely fill any holes and to the end of the dataset. You can set a value to only extend the fill out that number of traces away from where a pick exists. Polygons: set inclusion or exclusion polygons to limit the smoothing operation. If you set an inclusion polygon, SeisWare only applies the smoothing within the polygon. Conversely, if you set an exclusion polygon, SeisWare only applies the smoothing outside the polygon.

Exercise  Display the horizon “H SNP” on the Basemap.  From the Main Launcher’s Horizon menu, choose Smoothing/Attributes. SeisWare opens the Horizon Smoothing/Attributes window (see Figure 74).


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Figure 74: Horizon Smoothing/Attributes Window

 In the Horizons list, highlight the “H SNP” horizon.  Highlight “nsask” in the Lines list, and select “Smoothing” from the Operations list.  In the Horizon Smoothing/Attributes window, leave the grid size fields at their defaults.  Set Operate on to Data Vales Only and click . SeisWare opens the Select Output Horizon Names window (see Figure 75).  Leave the Output Horizon name as “H SNP SM”, and click horizon.

to have SeisWare create the



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 Open a new Basemap, display this new horizon, and compare the horizon with the unsmoothed original.  Repeat the process, but this time set the Operate On to All Values and have Fill Holes and Expand Edges checked on, and change the Output Horizon name to “H SNP SMI”. Compare this horizon with the other two.

Figure 75: Select Output Horizon Names Window

Computing Horizon Attributes Horizon attributes are computed in a similar way to smoothing in that the calculation is still performed over the area of data specified in the Parameters fields. The input horizons and lines are selected also selected in the same manner as smoothing. The smoothing parameters will be grayed out. The attribute Operations are: Dip: compute the dip or slope of the horizon surface over the grid size Azimuth: the direction of the slope of the horizon surface, referenced to the inline direction (output in degrees)


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Azimuth (True North): the dip or slope direction of the horizon corrected to true north, instead of the inline direction (output in degrees). Use this if you are computing and mapping the azimuths of several 3Ds at the same time. Gradient: the magnitude of the dip of the horizon. Use this to help detect faults. Edge Detection Inline: to enhance edges in the inline direction Edge Detection Crossline: to enhance edges in the crossline direction Edge Detection Diagonal Down: to enhance edges from the upper left to the lower right direction Edge Detection Diagonal Up: to enhance edges from the upper right to the lower left direction Difference Inline: to compute the difference between adjacent inline picks. Use this to help detect edges. Difference Crossline: to compute the difference between adjacent crossline picks Laplacian: the change in the dip of the horizon. Use this to help detect both sides of edges. Mean Curvature: the average of two orthogonal curvatures. Used primarily to derive other curvature attributes, but similar results to maximum curvature. Gaussian curvature: the product of the principal curvatures (minimum curvature and maximum curvature). Maximum Curvature: the largest absolute curvature at any point. Use this to help delineate faults, and their orientation. Minimum Curvature: the curvature perpendicular to the largest absolute curvature. Use to show faults and fractures. Most Positive Curvature: the most positive curvature of a surface at a certain point. Use to exaggerate faults.



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Most Negative Curvature: the most negative curvature of a surface at a certain point. Dip Curvature: the curvature in the direction of maximum dip. Use this method to enhance differently compacted features. Strike Curvature: curvature in the perpendicular direction to dip curvature.

Exercise  Highlight the horizon “H SNP SMI” in the Horizons list.  Select the “nsask” 3D from the Lines list.  Run the following Operations, click , and leave the Output Horizon names at their defaults: o o o o o

Dip Azimuth Gradient Edge Detection Inline Edge Detection Crossline – change this Output Horizon name to “H SNP SMI EDGE X” o Most Positive Curvature  Use one of the Dip or Azimuth color palettes and display each attribute.


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SEISMIC ZONE ATTRIBUTES The seismic zone attributes function calculates and maps seismic traits through a dataset. You can generate new horizons, with appropriate names for each specific attribute, to observe the results of a calculation. After specifying the parameters, SeisWare generates each horizon to best highlight the desired attribute from a dataset. When running the seismic zone attributes, you can select both 2D and 3D Seismic data either from the list or off of the Basemap. The Attributes section determines the calculations that SeisWare will perform. For each attribute you select, SeisWare generates a new horizon. It adds an appropriate extension to the end of the Base Output Name for each calculation, for example, with a base name “Test_D” it names a crosscorrelation ‘Test_D_CC’. The Seismic Zone Attributes window remembers previous calculations, including horizons used, time windows, a Base Output Name, and wavelets. You can change or remove this information, and change the Base Output Name to create new horizons. If you leave the Base Output Name the same, then the old results will be overwritten.

Selecting Seismic Attribute ATP and ATT: calculate the thickness of a peak or trough in time (ms). If multiple peaks or troughs are in the time window, SeisWare sums them. Use this for seeing when a wavelet changes from a single to a double wavelet. Spikes in the color histogram are based on the data’s sample rate. AUP and AUT: calculate the area of a peak or trough (no units). The area is defined as the sample value multiplied



109

by the sample rate. SeisWare sums it for all samples that are peaks or troughs. If multiple peaks or troughs are in the time window, SeisWare sums them. AVG and ABS: calculate the average amplitude within the selected area (amplitude units). It is the sum of all amplitudes in the time window divided by the number of samples. For ABS, SeisWare takes the absolute value of each amplitude sampled and divides it by the number of samples in the time window. MAX and MIN: output the maximum or minimum value within the time window (amplitude units) MAXP and MAXN: output the maximum positive or maximum negative value within the time window (amplitude units) RMS: calculate the root mean square for summing amplitudes within the time window CC (cross-correlation coefficient): compare a selected wavelet to the wavelets within a picked horizon in the frequency domain, and output a correlation value. If two wavelets are exactly the same shape, the output is 100%, otherwise, the value is less than 100%. If two wavelets are exactly the same shape, but have different amplitudes, they are still 100% matched. MHD (Manhattan distance): compare similarities between wavelets in a zone using a statistical measurement to show the degree of similarity. A perfect match (identical) is 100% and a low match is 0%. It takes the sum of the differences between the wavelets and divides by the sum of the max possible differences of two equal length wavelets with the same number of samples. Amplitude and phase differences affect the result of this measurement.

Defining Windowing Method Use the Windowing Methods field to specify how to perform the calculation in the Z direction. The options are:


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Define By Single Horizon: hang a wavelet from a single horizon. Set a top and bottom offset to determine the time range to use in the calculation. SeisWare adds the Top Offset to the horizon to define the start time of the data window, and the Bottom Offset to define the end time of the data window. Define Using Time Range: set fixed upper and lower times for this calculation. Specify a fixed starting time for the Upper Time, and a fixed ending time for the Lower Time. Define Between Horizons: set the Upper Horizon and Lower Horizon time window for the calculation. Use the Upper Horizon Offset and Lower Horizon Offset to allow for an increase or decrease in the time window around each horizon. SeisWare will stretch or squeeze wavelets to perform the cross-correlation. The Upper Horizon defines the start time of the data window, and you can use the Upper Horizon Offset to add to the Upper Horizon to further define the start time. The Lower Horizon defines the end time of the data window, and you can use the Lower Horizon Offset to add to the Lower Horizon to further define the start time. Define Between Horizon and Datum: use a Horizon and a Datum to set the time window for the calculation. The Horizon defines one end of the time window, and you can use the Horizon Offset to add to the horizon to further define the time window. The Datum is a fixed time that specifies the other end of the time window. There are additional options that must be specified when selecting certain windowing methods. Top Offset/Bottom Offset: when specifying a horizon, adjust the time window based off of the horizon using the top and bottom offsets. The value specified is added to the horizon. For example, to go 10 ms above and below a horizon, set the top offset to “-10” and the bottom offset to “10”.



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Amplitude Threshold: this is the start for the amplitude data window, at which SeisWare will calculate a peak or trough function. If you set a threshold of zero, SeisWare uses an entire peak or trough, from the zero crossing to the maximum amplitude, in the calculation. This is similar to setting a time window around a horizon specifically defined by amplitude. Select Wavelet: only the CC and MHD algorithms need a wavelet and this is selected from the Basemap or Seismic Viewer by clicking on a trace. It is useful to select a wavelet when performing any attribute calculations to ensure that you have set a correct time window. Polygons: by selecting a polygon that you generated or imported, you can include or exclude an area from the output horizon. For an inclusion polygon, SeisWare restricts the output horizon to the area of that polygon. For an exclusion polygon, SeisWare generates the output horizon with blank traces and no picks within the area of the polygon.

Exercise  From the Main Launcher’s Seismic menu, choose Seismic Zone Attributes (Figure 76).


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Figure 76: Seismic Zone Attributes Window

 Select the “nsask MIG 0” 3D from the Seismic Lines selection field.  To create a new horizon, enter the name “Test_D” in the Base Output Name field.  Check all the boxes in the Attributes section of the Seismic Zone Attributes window, and SeisWare will perform all the calculations.  Choose “Define By Single Horizon” for the Windowing Methods.  Select “D” from the Horizon drop-down field. SeisWare uses this as a datum.  Enter “-10” in the Top Offset field, and “10” in the Bottom Offset field.  Leave the Amplitude Threshold at zero.  From the Basemap, select line 26 and open it in the Seismic Viewer.  Click Select Wavelet in the Seismic Zone Attributes window.  In the Seismic Viewer, click on trace 569. SeisWare displays a wavelet below the Select Wavelet button, and inserts the wavelet information in the Wavelet



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Info. section of the window (see Figure 77). The wavelet picked is in the channel to show the correlation across the 3D.

Figure 77: Seismic Zone Attributes Window – Select Wavelet Section

 Click

to run the calculation.

 To view the results of the seismic zone attributes calculation, display each newly created horizon on the Basemap. The new horizons are: o o o o o o o o o o


Test_D_ATP Test_D_ATT Test_D_AUP Test_D_AUT Test_D_AVG Test_D_ABS Test_D_MAX Test_D_MIN Test_D_MAXP Test_D_MAXN

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o o o o

Test_D_RMS Test_D_CC Test_D_MHD Test_D_MHD



WAVELET ANALYSIS The Wavelet Analysis function calculates the correlation between several selected wavelets in a time window defined over a data set. SeisWare displays the results of the analysis as a horizon, with values ranging from 0 and 100. These values represent the correlation between the selected wavelets and the seismic volume that they are being compared across. The correlation coefficient and Manhattan distance calculations are the same as those used in Seismic Zone Attributes. In Wavelet Analysis, however, you can compare multiple wavelets across your dataset. This can help you identify certain zones or facies in the dataset. You can use both 2D and 3D data in the analysis. To select the seismic to use in the Wavelet Analysis calculation, either hold Ctrl and select multiple lines, or drag out an area on the Basemap.

Selecting an Algorithm The Algorithm section of the Wavelet Analysis allows you to select from two options – correlation coefficient and Manhattan distance.

Correlation coefficient This performs a cross correlation between the selected wavelet(s) and the rest of the data specified. To view the correlation between the wavelets, use the option.


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When viewing the results, a correlation value of 100% means high correlation (exact match) and 0 means a poor match. This type of correlation is not directly affected by amplitudes but is looking at the shape of the waveform.

Manhattan distance This technique performs a statistical correlation between the selected wavelet(s) and the data specified. It takes the sum of the differences between the wavelet and the trace data in the volume and divides it by the sum of the maximum possible difference between the two. This method uses two equal length wavelets with the same number of samples. The output for an exact match is also 100% and poor match at 0. This type of comparison takes into account how amplitude changes are affecting the waveform shape.

Defining a Seismic Data Window Use the Windowing Method to specify how SeisWare is to perform the calculation in the Z direction. Depending on what windowing method you choose, these fields, and the information that you need to enter, change. There are four Windowing Method options. Define By Single Horizon: use this method to hang a wavelet from a single horizon. Set a top and bottom offset to determine the time range to use in the calculation. SeisWare adds the Top Offset to the horizon to define the start time of the data window, and the Bottom Offset to define the end time of the data window. Define Using Time Range: use this method to set fixed upper and lower times for this calculation. Specify a fixed



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starting time for the Upper Time, and a fixed ending time for the Lower Time. Define Between Horizons: use this method to set the Upper Horizon and Lower Horizon time window for the calculation. Use the Upper Horizon Offset and Lower Horizon Offset to allow for an increase or decrease in the time window around each horizon. SeisWare will stretch or squeeze wavelets to perform the cross-correlation. The Upper Horizon defines the start time of the data window, and you can use the Upper Horizon Offset to add to the Upper Horizon to further define the start time. The Lower Horizon defines the end time of the data window, and you can use the Lower Horizon Offset to add to the Lower Horizon to further define the start time. Define Between Horizon and Datum: use this method to use a Horizon and a Datum to set the time window for the calculation. The Horizon defines one end of the time window, and you can use the Horizon Offset to add to the horizon to further define the time window. The Datum is a fixed time that specifies the other end of the time window. Once you have set the windowing method the window will be applied when you select wavelets. If your windowing method changed after you select your wavelets, the wavelet window will not be updated.

Selecting Output Parameters The Base Horizon Name is used for naming the results generated from the Wavelet Analysis. SeisWare adds an extension to the Base Horizon Name for each calculation it performs, for example, using the Base Horizon Name as “Test_C” it saves wavelet ID 1 as “Test_C_001” for individual CC results, and “Test_C_BEST” for the best output CC result. (You can find the wavelet number in the ID column of the Wavelets section in Figure 79).


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There are several types of results that can be created. Output Individual CC Results: this compares a selected wavelet to the wavelets in the window across an entire data set, and outputs a correlation value. SeisWare produces one CC horizon for each wavelet selected. If you choose three wavelets, SeisWare produces three new horizons, with the extensions _001, _002, and _003. Output CC IDs: SeisWare generates horizons with BESTID or WORSTID appended to the base name. The BESTID horizon displayed on the Basemap is based on the wavelet with the best individual CC result for each trace. The results assign each trace the color of the wavelet to which is had the highest correlation. These colors will fade to the Fade Color to indicate the level of correlation. The WORSTID horizon displayed on the Basemap is based on the wavelet with the lowest CC result for each trace. This is based on which wavelet ID has the worst CC result, not on the degree of wavelet correlation. For the output best and worst CC results, to display multiple wavelets on a single horizon, the results take the CC values between 0 and n*100 (not between 0 and 100), where n is the number of wavelets used in the calculation. Wavelet ID 0 has values between 0 and 100, wavelet ID 1 has values between 100 and 200, and so on. Output Best CC Result: this generates a horizon that contains the best CC value between all wavelets for that trace. The Fade Color isn’t used, only the pure color of the wavelet is applied to the results. Output Worst CC result: this generates generate a horizon that contains the worst CC value among all wavelets for that trace. The Fade Color isn’t used, only the pure color of the wavelet is applied to the results. Use absolute value: this is only used for the Cross Correlation algorithm. If your data is not phased tied, you can compare the waveform across datasets that have reversed polarity.



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Selecting Output Colors The custom palettes enable you to scale output horizons properly when you view them on the Basemap. Output colors enable you to cut off the output horizon at set values. SeisWare can only highlight a certain range of data on the horizon, and it cuts off less relevant results with the selected cut-off color. The default scale for the custom color palette is between 0 and 100 for each wavelet. The Output Colors options are: Cut-off for Best Results: when SeisWare uses several wavelets, the best match results have the majority of values between 90 and 100. To observe the results better, you can set a cut-off value to increase the dynamic range for the relevant values. The value you enter blocks values from zero to that number, and SeisWare uses the remaining range to apply the Fade Color To. If you specify 80, 0 to 80 is a solid Cut-off Color, and 81 to 100 show the defined wavelet color and faded values. This only affects the color palette, not the horizon values. Cut-off for Worst Results: when SeisWare uses several wavelets, the worst match results have the majority of values between 0 and 10. To observe the results better, you can set a cut-off value to increase the dynamic range for the relevant values. The value you enter blocks values from zero to that number, and SeisWare uses the remaining range to apply the Fade Color To. If you specify 20, 21 to 100 is a solid Cut-off Color, and 0 to 20 show the defined wavelet color and faded values. This only affects the color palette, not the horizon values. Cut-off Color: this is the cut-off color range that appears in the horizon ribbon. It is a solid color, representing data that is outside the selected range.


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To change the color, click on the color button. When SeisWare displays a color palette, click on the color that you want and click OK. Fade Color To: the Fade Color To is the color to which the wavelet color (and horizon color on the Basemap) fades as the cross-correlation values decrease from a 100% match. If the wavelet color is red and the Fade to Color is black, the best result is represented as red, and the horizon fades to black as the correlation for the wavelet decreases. SeisWare generates a color scheme for each horizon. To ensure that they are being used on the map: Right click on the Basemap and select General Properties. In the General Basemap Properties window, select Color Properties and Colorbar/Histogram. Check Automatically Save Color and Scale Information For Each Horizon. Now SeisWare will scale the colors correctly when you view the output horizons.

Selecting Wavelets In the Wavelets section, you choose the wavelets for the calculation. When you first open the Wavelet Analysis window, it might have wavelets already in the list. These are wavelets from previous calculations. To remove any existing wavelet that you don’t need, click on the wavelet in the list and click Remove, or click Remove All to remove all listed wavelets. Select the wavelets using the Add button. This launches another window that allows you set a color and name for the wavelet and will have the currently set window based on the horizons, and the offsets that you entered previously in the main dialog (see Figure 78). You can edit this information in this window.



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Figure 78: Add Wavelet Window

The available windowing methods are identical to those in the main window, and wavelet windows can be individually set. In most cases you will want the wavelet window used in the analysis to be the same as the Seismic Data Window. Using the Use Seismic Data Window windowing method will allow you to change the range of data being used in the analysis without having to change each individual wavelet window. Select the wavelet by clicking on the Select Wavelet button and then clicking on a trace in the Seismic Viewer or on the seismic data on the Basemap. SeisWare fills in the information for the wavelet in the Wavelet Info. After you click OK, SeisWare returns to the Wavelet Analysis window and adds the new wavelet to the list, with its assigned color and assigned name. SeisWare also assigns an ID number to the wavelet, starting at 0 and increasing by one, as more wavelets are selected. The selected wavelets are what will be used in the calculation.


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When selecting the wavelets, keep in mind that the colors will be displayed alongside each other in on the output horizons. Choose bright contrasting colors for the best results. You can select as many wavelets as desired, however as the number of wavelets increase, the results will start to look very cluttered. Once a wavelet has been selected, it can be saved so that it can be used in other analyses. Simply press the Save button. To use the saved wavelet press the Load button.

Saving Parameters Once you have set up all of the parameters for your analysis, you can save them by pressing the Save button on the main window. This will allow you to reload you exact parameters, including wavelets, at a future time. Press the Load button to use saved parameters. By default the parameters of the analysis are saved to a file as soon as you press OK or Apply. These are saved using the Base Horizon Name.

Exercise  To open the Wavelet Analysis window, select Wavelet Analysis from the Main Launcher’s Seismic menu (see Figure 79).



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Figure 79: Wavelet Analysis Window

 Select the “nsask MIG 0” 3D from the Seismic Lines section.  Select Correlation coefficient from the Algorithm section.  For the Windowing Method, choose “Define By Single Horizon”.  Select “C” from the Horizon drop-down field. SeisWare uses this as a datum.  Enter “Test_C” in the Output Basename field for the name of the new output horizon.  Enter “30” in the Top Offset field and “60” in the Bottom Offset field.  Click to check on Output Individual Results, Output Best Result, Output IDs, and Output Worst result.  Check on Custom Color Palettes.  No polygons will be set so leave this unchecked.  For Cut-off for Best Results, enter a value of “50” so the range becomes 50-100.


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 For Cut-off for Worst Results, also enter a value of “50” so the range becomes 0-50.  For Cut-off Color, change the color to black.  Leave the Fade Color To at the default of “Black”.  From the Basemap, select line 161 and open it in the Seismic Viewer.  In the Wavelet Analysis window, click and SeisWare opens the Add Wavelet window (see Figure 80).

Figure 80: Add Wavelet Window

 Click and click on trace 543 in the Seismic Viewer. SeisWare displays the wavelet in the Select Wavelet section.  Change the Color from the default of black to red (click on the black square, click on the red color in the Color window, and click

). This is the



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color that SeisWare will apply to the wavelet, and to the horizon on the Basemap.  Leave the Wavelet Name at the default “Wavelet 0”. You can name your wavelets based on where or what they represent.  When you have selected the wavelet and checked or changed the parameters, click . If you need to change the parameters of a wavelet, highlight the wavelet, click , and make your changes in the Add Wavelet window.  Now repeat the procedure and add another wavelet on trace 536. Change the color to yellow. Again, add another wavelet for trace 576, changing its color to green (see Figure 81).

Figure 81: Wavelets Section with New Wavelet

 Click , and SeisWare opens the QC Wavelets window (see Figure 82). It shows all the wavelets in the list, and the wavelet and the horizon crossing. Use this window to sort the wavelets, from left to right, by the wavelets’ correlation values or their IDs.


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Figure 82: QC Wavelets Window

 After you have set all parameters and selected the wavelets, click 

Click

. to complete the calculation.

 Look at the horizons be selecting them from the Basemap’s Horizon to ribbon drop-down field. The new horizons are: o o o o o o

Test_C_000 Test_C_001 Test_C_BEST Test_C_BESTID Test_C_WORST Test_C_WORSTID

 Repeat the calculation using the Manhattan distance algorithm. Change the Base Horizon Name to “TEST_C_MHD” and leave all other parameters the same.  Click to complete the calculation. The new horizons are:



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o o o o o o


Test_C_MHD_000 Test_C_MHD _001 Test_C_MHD _BEST Test_C_MHD _BESTID Test_C_MHD _WORST Test_C_MHD _WORSTID

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ATTRIBUTE CALCULATOR This application enables you create an attribute volume from any of the listed algorithms. The options include semblance, trace mixes, and curvatures. Once the algorithm has been selected you must select the parameters to use, which will differ depending on the attribute selected. Attribute volumes can be displayed in the Seismic Viewer or in the 3D Seismic Visualizer. You may need to change the data scaling to view the data properly. To view the volumes on the Basemap, a time slice needs to be created in the Create Time Slice application.

Selecting Seismic Files The Seismic Files section lists all of the lines that you are able to run the attribute on. You are only able to select one seismic line at a time, and you should ensure that the correct version of the line has been selected. After the line is selected, SeisWare automatically fills the Output Window section with the full extents of the line. To restrict the load, you can modify the extents by typing into the fields. If you want to limit the extents of a 3D, you click Select From Map and drag out an area of interest on the Basemap. The line and trace ranges will update based on this selection.

Selecting Attribute Operation You can select all of the attributes you wish to create volumes for. To select multiple attributes, hold down the Ctrl key while selecting attributes from the list.



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The Attributes available are: Semblance: designed to find discontinuities in the data. Trace Mix: runs an average across a specified number of traces. Trace Mix Triangulation: runs a weighted average across a specified number of traces. Median: will find the median across a specified number of traces. Dip Magnitude: gives the size of the most dominant dip at that location, based on the result from the dip steered semblance . Dip Azimuth: gives the direction of the most dominant dip at that location, based on the result from the dip steered semblance . Mean Curvature: approximates the average curvature through a point. Visually it may not convey any additional information, but is used for deriving other attributes. Gaussian Curvature: indicates whether a surface has been warped or not. It gives measure of distortions of a surface. Maximum Curvature: measure of the maximum curvature (positive or negative) of the surface at a point. Useful for delineating faults and fault geometries. It shows anticlines and domes. Minimum Curvature: curvature perpendicular to the maximum curvature. Useful for identifying fractured areas. It highlights synclines and bowls. Most Positive Curvature: most positive value obtained from a search of all possible normal curvatures at a point. Useful for delineating subtle faults, fractures, flexures and folds. Most Negative Curvature: most negative value obtained from a search of all possible normal curvatures at a point. Also useful for delineating subtle faults, fractures, flexures and folds.


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Dip Curvature: curvature extracted along the dip direction and measures the rate of dip variation within the direction of the maximum dip. It is helpful to identify the throw as well as the direction of faults. In tensional terrains it correlates with open fractures. Strike Curvature: extracted along a direction perpendicular to the dip curvature. In a compressional terrain large values will correlate to open vs. closed fractures. Shape Index: used to describe the localized structure such as a dome, bowl, ridge, plane etc.

Defining Data Window These options limit the time window over which SeisWare runs the algorithm. Trace/Line Window: specifies how many traces in the inline and crossline direction away from a central trace that will be used in the operation. This should always be an odd number. Vertical Window: specifies how many samples to use in the semblance algorithm. This should also be an odd number. When you set the vertical window, the actual window depends on the sample rate of your data. If the data has a sample rate of 2 ms and you set a Time Window (samples) to 5, 10 ms of data is used. Dip Steering Window: specifies how many samples to use in the dip steering semblance algorithm or any of the curvature algorithms. As you increase this number, the number of calculations increases to test more scenarios using different dip cubes. Derivative Window: when using any of the curvature algorithms, this specifies how many dips across are used when calculating the derivative of the dip.



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Specifying Output Parameters For the final output, you must specify a file description. SeisWare does not keep any record of what you have done, other than changing the type descriptor. If you have limited or changed any of the default settings, this is a good place to record these changes. By default, the Type will be changed to the Operation name, and the version number left the same as the starting seismic line. You can override these settings.

Exercise This volume has already been created for you so do not complete the process.  From the Main Launcher’s Seismic menu, choose Attribute Calculator. SeisWare opens the Attribute Calculator window (see Figure 83).


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Figure 83: Attribute Calculator Window

 In the Seismic Files list, select the “nsask MIG 0” 3D.  In the Output Parameters section, enter “First Semblance” as the File Description.  Leave the Type, Version, and Output Folder at their defaults.  Check on Add to Working Set.  In the Data Windows section, select the Operation as “Semblance”.  Leave the Trace Window and Line Window set to “5”.  Set the Vertical Window (samples) to “5”.  Set a Start Time of “600” and an End Time of “800”, and leave the line and trace numbers at the full extents.



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 Click you.

as the volume has been created for

Displaying an Attribute Volume Once the Attribute Calculator is finished, you will have a new version of the volume. This volume can be viewed in your seismic viewer. When viewing attribute volumes, you may need to set up a user defined scaling option as explained in the exercise below since all output values are between 0 and 1. This volume can also be used to create time slices that can be displayed on the Basemap or in the Seismic Viewer.

Exercise 1. Displaying a semblance volume in the Seismic viewer  Open line 205 of the semblance volume in the faulted area in the NW corner of the volume. You may have to change the line version to the SEM volume using the right mouse button menu and selecting Versions.  Open the Seismic Display Properties to the Trace Style tab. Set the display to “Interpolated Density” using a “Grey Scale Inverted” color bar. On the Trace Scale tab use a “User Defined” scale mode and set the range to Minimum “0.25” and Maximum “ 0.75”. You can see colors surrounding the channel showing you the subtle differences (see Figure 84).


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Figure 84: Semblance Cube in the Seismic Viewer

2. Displaying an Attribute Volume in the 3D Seismic Visualizer  From the 3D Seismic Visualizer, select Load Data from the File menu.  Uncheck Display working set only.  Select the volume “nsask SEM 1” and move it to the Visible Seismic 3D list.  Click on screen.

at the bottom right of the

 Go to the Seismic Color Properties page (see Figure 85).  Set the Colorbar to “Gray Scale Inverted”, the Scale Mode to User Defined, User Minimum Amplitude to “0.25” and User Maximum Amplitude to “0.75”.



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Figure 85:Seismic Color Properties for Semblance

 Click

to exit the 3D Seismic

Properties, and to close the General 3D Visualizer Properties. You will now see the Semblance Volume displayed in the 3D Seismic Visualizer.  From the 3D Seismic Visualizer, select Load Data from the File menu.  Remove “nsask SEM 1” from display and select “nsask Maximum Curvature 1” for display.  Click


to view.

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Figure 86: Semblance and Curvature in the 3D Seismic Visualizer



SPECTRAL DECOMPOSITION Spectral decomposition is a process that allows you to break down the seismic response into different frequencies using the discrete Fourier transform. Thinner beds often get stacked during processing into one event. By transforming the data into the frequency domain using a discrete Fourier transform, the characteristic frequency expression of the thin bed is shown. Phase spectra can indicate lateral geologic discontinuities. In SeisWare, this is done with a two step process. The first step is to generate a Frequency Slice that allows us to better see the contribution of each individual frequency to the seismic wavelet. From this we can isolate a particular frequency of interest. The output Frequency slice file has a z component that is frequency. The next step is to generate Discrete Frequency/Time Slices at that specific frequency to give us a more detailed view of the thin bed response over a particular data window in the time domain. The output Discrete Frequency/Time Slices has a z component that is in time or depth depending on the source data. When outputting the data, by default, slice volumes are created. You also have the option to create a SEG-Y volume that can be used in the 3D Seismic Visualizer, or looked at in the Seimic Viewer.

Selecting Seismic When creating either the Frequency Slice or the Discrete Frequency/Time Slices, the Data Loading Extents fill in automatically when you select a 3D. To limit the input data, type in a new range, or use the Select From Mapoption to drag out an area on the Basemap.


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Defining Windowing Parameters In the Windowing Parameters window you specify the interval over which you wish to perform the frequency analysis. The data can be limited using time ranges or offset from horizons.

Frequency Slices When creating Frequency Slices the time window should be narrowed on the region of interest. In general, the lower the dominant frequency, the larger the window required. A rule of thumb is a 100 ms window for a 50 Hz frequency. Use the Window Taper to limit rogue frequencies and ringing.

Discrete Frequency/Time Slices When generating Discrete Frequency/Time Slices the Time Window can be as large as desired. The Frequency/Time Slices option becomes active and the slice window set should be the same size as the Time Window used when generating the Frequency Slice. This window will be used around each sample and moves through the Time Window, therefore the Time Window can be as large as you need it.

Selecting Output Options Frequency Slices In the Output window you select the range of frequencies for which you would like slices created, and the increment for the slices. You can output frequencies from 1Hz to 250 Hz



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(Nyquist). You will also create a Description and Slice Group for the file and specify the output directory of the file. You can optionally create a SEG-Y of the output. Bear in mind that this will be a frequency volume.

Discrete Frequency/Time Slices For Discrete Frequency/Time Slices, you should pick specific frequencies based on the results from the Frequency slice. If you enter a range of frequencies, a separate slice will be created using each frequency for the time window. You can optionally create a SEG-Y of the output. Bear in mind that this will only contain positive values as it is based on the amplitude response in the frequency domain.

Normalizing The contribution of the different frequencies to the trace data over the time window can vary significantly. The frequencies with smaller contributions will display with smaller amplitudes, making them appear washed out when comparing to later slices. This problem can be eliminated by normalizing the slices. To normalize the data for each frequency slice use the Normalize Amplitudes option. This process is similar to spectral balancing.

Exercise 1. Generating a Frequency Slice:  Select Spectral Decomposition from the Main Launcher’s Seismic menu (see Figure 87).


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Figure 87: Spectral Decomposition

 Select Generate a Frequency Slice.  Select the "nsask" 3D from the Seismic Files list.  Leave the extents as selected and click

.

 Select Define By Single Horizon.  Select Horizon “C” and enter a Top Offset of “-25” and a Bottom Offset of “75”.  Select a Cosine Window Taper and put the Taper Percent at 15% and click 88).

(see Figure



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Figure 88: Spectral Decomposition Window Parameters

 Enter a Start Frequency of “1” and an End Frequency of “150”.  Leave the Increment as “1”.  Check on the Normalize Amplitude option and set the Values dropdown window to Amplitude.  Enter a Slice Group and Description in the Slice File section. Make sure to include the frequency range and taper information as this will not be stored elsewhere.  Leave the Output Folder set to the “Project Directory”.


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Figure 89: Spectral Decomposition Output

 Uncheck Output SEG-Y and click then

and

to create the slice file.

 Press to close the Spectral Decomposition window. 2. Viewing Time Slice You can now view the slice you created to determine the frequencies that best illustrate the desired features. These are the frequencies for which you will generate discrete frequency/time slices in the next step.  From the Basemap go to Selection and choose Time Slice, or choose the Time slice selection icon from the Basemap (

).

 Hold Ctrl and left click on the 3D opening the Time slice Selection window.



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 Select the Spectral Decomposition slice you just created.  Click Display to view.  In the Seismic Display Properties change the color to “Rainbow"  Scroll through the slice to see at what frequencies the channel and tributary are best demonstrated (see Figure 90). Remember that each slice is representative of the frequency displayed in the box to the right of the scroll bar in the Seismic Viewer.

Figure 90: Time Slice

3. Generating a Discrete Frequency/Time Slice As you scroll through the Frequency slice you can see that a channel and tributary show up very clearly between 61and 62Hz. Now that we have narrowed down the frequency range


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we can run the Spectral Decomposition again, this time using the Generate Discrete Frequency/Time Slices option. This option will generate a time slice volume for each selected frequency with the z component of the slice file being time. 

Reopen the Spectral Decomposition dialog and select Generate Discrete Frequency/Time Slice.

 Select the nsask 3D from the Seismic Files list, leave the full extents and click

.

 Select Horizon “C” and leave the Top Offset at “-25”, the Bottom Offset at “75” and the Cosine Taper at “15” (see Figure 91).

Figure 91: Spectral Decomposition – Windowing Parameters

 The Datum Time represents the time that will be given to the first slice created. Enter an appropriate Datum Time.  Set the Slice Window to “100”. Click

.



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Figure 92: Output

 Set the Start at “61” Hz and the End at “62” Hz. Leave the increment as “1” (see Figure 92). This will create two slice files – one at 61 Hz and one at 62 Hz.  Enter a Description and a Slice Group for the slice files. The frequency for each slice file will be added to the end of the description. For example “100ms C 25-75 – 61Hz”.  Don’t output a SEG-Y file.  Click

and

.

4. Viewing Time Slices  Display one of the new time slices to determine at what time certain events are occurring.


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AUTOMATIC MISTIE ANALYSIS Seismic lines of different vintages can have varying static, phase and gains because of differences in acquisition and processing parameters. You can compensate for these misties by using the interactive mistie analysis on a line-by-line basis, or by using the automatic mistie analysis on a group basis. The automatic mistie analysis computes the static, phase, and gain mistie at each intersection, then uses a least-squares routine to compute a single static, phase, and gain to apply to each seismic line to minimize the misties. You can save the automatic mistie analysis as a ‘run’. This allows you to save different analyses and restore them later. The first time that you use the Automatic Mistie Analysis, you will have to create a new run before the full Automatic MIstie Analysis window opens with all of the options. To perform a mistie run, you need to select the lines that will be used for the run. To do so, use the “Add or Remove Line” button to open a dialog that allows you to select your 2D lines from the list or the Basemap. If selecting lines off the Basemap, click and drag out an area to highlight lines, and use the arrow to move the lines between the lists. Based on the lines selected, all intersections will be displayed in the Mistie Dialog, and an initial calculation will be performed. To perform the mistie analysis on the intersections, modify the Parameters as needed, and click on the “Calculate” button. If the results are satisfactory, you can process the changes into the seismic lines using the “Apply Results” button. This will create a new version of the seismic line with the changes applied.



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Mistie Parameters The following is a list of all of the selection paramemters in the Automatic Mistie Analysis window. Add or Remove Line: Use this to add seismic lines to the run. Use All Intersections: This will toggle on all intersections listed in the table in the Single View tab. Minimum Confidence: Use this to set a minimum confidence value. Any intersection with a confidence value below the value specified will be deactivated from the run and will not be included in the calculation. Save As: This allows you to save the table of results to a file for viewing. Manual Mistie: Set the time window and the number of traces that SeisWare uses on each side of the intersection for the calculation. You also have the option to Display Raw Intersection and Display Corrected Intersection, both of which will display the data at that intersection in the manual mistie analysis window, with or without corrections applied. Automatic Mistie: This section allows you to specify if to calculate a Horizon or Seismic Mistie and some additional options for the output. Reference: Check this on to specify a line that should be used as a reference. No changes will be made to the reference line and the calculation will come to solution so that other lines are adjusted to match the reference. Horizon Mistie: If toggled, you will be able to select a horizon that has been picked on your data. SeisWare will then try to shift your seismic lines up and down so that the horizon is continuous across the entire data set. The “Advanced…” button allows you the option to change how the results are applied (either to the seismic lines, or to the horizons).


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Seismic Mistie: Using the data in the windows specified in the Manual Mistie section, SeisWare stacks the traces into a single trace and cross-correlates the two resulting traces to compute the optimum static, phase, or gain to apply to eliminate the mistie. You can toggle on any combination of the three parameters to be calculated. Disable intersections with the RMS=0: This removes intersections that have zero RMS values, to avoid a mistie with dead traces. Restrict phase to angle increments: When checked you can specify an increment by which to rotate your phase. SeisWare will then round the phase to the nearest increment when applying the result. Filter the Data: This will filter the data before SeisWare runs the calculation. This does not reprocess the data but filters it, in memory, for the mistie calculation. Calculate: This will calculates the optimum single static (Static Adj), phase (Phase Adj), and gain (RMS Adj) to apply to the lines. These changes are saved to the database until processed into the lines. Apply Results: This will batch process the lines with the changes that have been calculated.

Output Views: Once the mistie has completed, you can display the misties in two ways – the Single View tab, with a list of every possible intersection that was selected, and the Dual View tab, with each line and the intersecting lines, once you select the line. In the Dual View tab, you can select a line to see the static, phase and gain that will be applied to the selected line. The Intersects With section displays all intersections between the highlighted line and all intersecting lines selected in the run. For each row, SeisWare lists the before and after statistics:



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The before columns are before any mistie correction is applied. The after columns list the information after the phase, static, and RMS corrections, listed in Seismic Lines, have been applied. Note that these are differences at the intersection location. The Confidence column is the correlation coefficient from the crosscorrelation with the data at the intersection. A check mark at the left of the Line column indicates that SeisWare is using the intersection in resolving the mistie. If you do not want to include this intersection in the mistie resolution, because of poor data quality, static problems, or any other reason, turn off the box.

Exercise 1. Creating a New Mistie Run  From the Main Launcher’s Seismic menu, select Automatic Mistie Analysis to open the Select Mistie Run window (see Figure 93).


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Figure 93: Select Mistie Run Window.

 Click on the toggle for “Create new run”.  Enter “First Mistie Run” in the Name and Description fields.  Click to open the Automatic Mistie Analysis window as shown in Figure 94.



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Figure 94: Automatic Mistie Analysis Window

 Click on the button and the Select Seismic Lines window should appear (Figure 95).  On the Basemap, click and drag an area to cover all of the 2D seismic data.  Click to move the selected lines from the Available Seismic Lines to the Seismic Lines Used list, and click


.

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Figure 95: Select Seismic Lines Window

 Enter a Start Time of “600” and an End Time of “1900”.  Set # Traces to “9”.  Leave the Reference line unchecked.  Ensure that Seismic Mistie is checked and that Static, Phase, and Gain are checked.  Ensure that Disable Intersects with RMS = 0 is checked.  Leave Restrict Phase to Angle Increments unchecked.  Check on Filter The Data. Enter a Low Truncation of “8”, a Low Cut of “12”, a High Cut of “40”, and a High Truncation of “48”.  Click the

button.

The results from the calculation are now displayed in the Automatic Mistie Analysis window. Every intersection that exists for the lines selected is shown on the Single View. The Dual View allows you to select a line and see a list of the intersecting lines.



Checking the Mistie Result Automatic mistie analysis is usually an iterative process. You generate a run and calculate the mistie corrections. Then you check the misties after correction to see how much the output is improved. In many cases, several intersections do not tie and they prevent the grid from resolving properly. This can be because of subsurface geology, such as faulting in the area, processing problems, or other factors. To drop these intersections from the mistie calculation, check off the box beside Line for the intersections. Then click the Calculate button again, and SeisWare calculates the mistie corrections without the deactivated intersections. You can also use “Display Raw Intersection” and “Display Corrected Intersection” to view the data at any intersection. SeisWare opens the Quick Mistie - Seismic Viewer window, with an arbitrary line displayed at the intersection of the two lines. It also opens a Quick Mistie - Zoom window over the start and end times defined, and the interactive Mistie Analysis window with the computed optimum corrections (see Figure 96). If using “Display Raw Intersection”, the data displayed is before any mistie corrections are applied. “Display Corrected Intersection” shows the displayed windows with the computed correction applied. Use the intersection displays to check the effectiveness of the computed mistie corrections.


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Figure 96: Quick Mistie – Zoom and Mistie Analysis Windows

Exercise  Choose the Dual View tab.  Highlight the first line in the Seismic Lines list, “CS030.FLT.FLT.0”.  Highlight line “NSX020.MIG.0” in the Intersects With section.  Click the Manual Mistie section.

button in the

 Check the zoomed seismic display and the crosscorrelation at the bottom of the Mistie Analysis window. Close the windows.  Click the button in the Automatic Mistie Analysis window.



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 Compare the zoomed seismic display and the corrected cross-correlation with the raw ones displayed earlier. To toggle back and forth, click the Display Raw Intersection and Display Corrected Intersection buttons.

Mistie Dots on the Basemap Another tool for checking the results of the Automatic MIstie Analyis is the mistie dot display on the Basemap. These pie diagrams display at all intersections on the Basemap. One segment of the pie represents the static mistie, one represents the phase mistie, and the third represents the gain mistie. You can look at these values before any mistie corrections are applied to the data and after using the results from the calculation. SeisWare posts the values that the pie colors represent beside each segment. These values are also annotated at the side of the color legend. Ideally for a good mistie result these differences should be close to 0, so check your color bar scale to determine what colors represent good (close to 0) and bad intersection.

Exercise  Open General Basemap Properties, and select Mistie Settings from the Color Properties menu.  Select “First Mistie Run” from the Mistie Run dropdown field.  Check on Show Misties Before Correction, and also check on Show Static Mistie, Show Phase Mistie, and Show Gain Mistie.  Check on Post Mistie Values and click


.

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SeisWare now displays pie diagrams at all intersections on the Basemap.  Open General Basemap Properties, and select Mistie Settings from the Color Properties menu.  In the Mistie Settings window, check on Show Misties After Correction, and click

.

Creating Jumpties The automatic mistie analysis only tries to resolve 2D intersections. If you have 3D datasets, 2D lines that do not intersect another 2D line, or well data that needs to be tied, you must create a jump tie. In order to add a jump tie you must close the Automatic Mistie window, then add the jump tie. To add a jump tie, use the Jump Tie icon (

) from the

Seismic Selection Toolbar. Select an existing mistie run and left click twice on a point where both 2D and 3D exist. Right click to add the point to the mistie run. After the tie is added, you can reopen the mistie run and the intersection (and 3D) will appear in the dialog. You can use the same method to create jump ties between well synthetics and 2D or 3D data, and 2D to 2D lines.

Exercise  From the Basemap, select the Jump Tie icon ( ) from the seismic selection drop down to open the Add Jump Tie window.



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Figure 97: Add Jump Tie Window

 Move your mouse onto the Basemap – it appears as a crosshair with the Select jump tie icon above it.  Click a point on a 2D line that is near SW3D. SeisWare fills the First Point list with all the data points close to your mouse click. If a 2D line isn’t highlighted, click on it to highlight it.  Click on SW3Don the Basemap near the 2D line you selected.  In the Second Point list, highlight the SW3D.  Right-click on the Basemap to end the jump tie. SeisWare now displays this jump tie in the intersection list in the Add Jump Tie window.


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 Re-open the Automatic Mistie window making sure to select the same run that you created earlier.  Click mistie.

to recalculate the

 Check the 3D to 2D jump mistie dots before and after the correction. Do not apply these results for this exercise.



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APPENDIX A: DEPTH SEISMIC Loading Depth Data SeisWare software cannot currently distinguish between milliseconds, meters or feet when loading in SEG-Y volumes. As a result, when you are loading your seismic data, you have to flag the SEG-Y volume as such. There are two ways to do this either in the Data Loading wizard, or in Seismic Line Properties, after the volume has been loaded.

Flagging Depth in the Data Loader: From the Data Format page of the Data Loading wizard, click on the button. In the Vertical Units field, use the Override dropdown to select the appropriate unit of the depth volume, either meters or feet. Note that when you click on , “Milliseconds” will show on the left by default.

Flagging Depth in Line Properties: After a line is loaded, you can change the vertical units of the volume in Seismic Line Properties. Go to the Files tab of Line Properties, and double click on the line to bring up the Detailed Properties. There is a Vertical Units dropdown that can be set to Milliseconds, Meters or Feet. After the data is loaded in with the correct units, the wells and associated data should line up appropriately.

Seismic Depth Datum: For newly loaded depth seismic there is a depth datum that is used to reference the data. This enables you to view your


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seismic in Subsea or TVD depths. Note that by default, seismic and grid data will all be displayed in subsea. The Depth Datum is assumed to be 0 for new data. To change the depth datum select Edit Seismic Datum from the Edit menu in Seismic Line Properties. You can change either the time or depth seismic datums here.

Horizons Horizons that are picked in time will only show up on time volumes, and horizons picked in depth will only display on depth volumes. You can work with your depth seismic in the same manner as you do with your time seismic. Please keep in mind that any horizons picked on a depth volume before the release of SeisWare version 7.04.00 were assumed to be picked in time. This may cause some conflict with any new work done as you move forward after the SEG-Y volume has been flagged with depth Vertical Units. To convert any existing horizons, use the Horizon Calculator. To correctly convert the old horizon, use the Calculation: "New Horizon" = "Old Horizon" * 1 specifying the Output Type as "Normal" and Units as either "Meters" or "Feet" to match the Vertical Units of your seismic.

Grids Grids should be created in the units that match your depth data, so that contours will associate with horizons appropriately. In the Grid and Contour dialog, ensure to use/turn off the metric toggle on the Grid Technique page as required.



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Other data items should behave as expected with no other changes required.

Annotation Changes In the Seismic Viewer, you can annotate the seismic in subsea or TVD. The default recommended and applied is subsea.

Changing seismic depth annotation: From the Seismic Display Properties go to the Annotation tab and adjust the Depth Annotation. Select the desired depth values.

Changing Tops Annotation: From the Seismic Display Properties go to the Tops tab and adjust the Top Value. Select the desired display for the depth values. On the Basemap, picked horizons can be displayed in either subsea or TVD. The default setting is subsea.

Changing Horizon Units on the Basemap From General Basemap Properties open the Ribbon Settings section of Color Properties and use the Show depth horizons in subsea to toggle the depth unit. In other applications in SeisWare, where the option to use a depth volume/depth horizon is present, you will often see a toggle for "Use Subsea". This will enable you to switch the assumption in that dialog from subsea to TVD


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APPENDIX B: SEISWARE GLOSSARY Acculink Allows a user to retrieve general well information and well tops directly from an AccuMap database. Active Only active files will appear on the Basemap and in dialog menus. Seismic, culture, grids, rasters, faults and horizons all have an Active flag associated with them. Active Dialogs Menus or windows of information that are associated the Basemap. These windows can be attached, or "docked," to any side of the parent window, or "floated" in their own independent miniature window. These include Colorbar, Criteria Legend, Current Selection, Line Tracker, Scale Bar, Status Bar Navigation Pane and Well Posting. Arbline Selector A tool that allows you to select 2D and/or 3D seismic for display in the Seismic Viewer. The left mouse button is used to select seismic segments, and right click is used to launch the Seismic Viewer. Bubbles Allows user to scale well symbols based on numerical information. CDP Common Depth Point numbering for a 2D. Typically this value increments by 1. Criteria Allows user to post a marker shape on a well symbol based on a specified condition. Culture Drawn or imported objects on the Basemap that include grid lines (township, section lines, lsd..etc), contours, polygons, land boundaries, bodies of water, roads, pipes…etc. Data Pipeline Allows you to retrieve data directly from various configured databases, and bypass the need for exporting and importing data. DIC Data Integrity Checker, used to troubleshoot data contained in a SeisWare project. Runs an analysis on specified data type and outputs a report. Docking View A window, such as an Active Dialog, that can be attached, or "docked", to any side of its parent window, or "floated" in its own independent window. Dongle License key used as a form of software security to prevent the illegal unsanctioned use of SeisWare. Most SeisWare dongles are green USB keys. Duplicate Tops Formation tops with identical name, source, and depth.



Ends and Bends The angle used to specify the amount that a 2D line can change direction before the change is drawn on the Basemap. 2D lines will appear smoother on the Basemap. For example if 5 degrees is set then any 2D line that has a bend of 5 degrees or less will draw straight. Fixed Size (Inches) Text sizes that are fixed and will not scale as you zoom in or out. Formations A geological formation. For a Top to exist in SeisWare the Formation must also exist. Generate Synthetic Uses the sonic log and velocity curve to create a synthetic track that can be placed in the Seismic Viewer. A generated synthetic can be manipulated within the Seismic Viewer. Goto Used to center the map on the data item selected and highlight it. Grid Coordinates that contain a z value to represent a surface (time, depth, etc.). Can be seen as a colored surface on the Basemap and is usually associated with a contour layer. GWC Grid, wells, and culture. Files usually used to setup a project. GWI General well information including UWI, Status, Depth Datum, and locations. Header Beginning of a SEG-Y file that contains all the information regarding the SEG-Y files contents. The header can be viewed in a SEG-Y viewer. Inactive Files that are in a project but not visible in layer properties or any other dialogs other then the properties dialog. Index File File used to map individual traces in a 3D SEG-Y file to their respective lines. All SeisWare 3D’s have one of these files and the file must reside in the same directory as the 3D. Inserted Synthetic allows the user to insert a SEG-Y synthetic track into the seismic viewer. This file can be bulk shifted but not manipulated in any other way. Key Map The portion of the Basemap that is currently visible in the window. Keyword A mapping of the byte locations for a SEG-Y file. Usually created when loading seismic. Layer Visibility Allows user to define which layers are visible at specified scales on the Basemap. Line Sequence Number Inline numbering for a 3D, typically displays as a step function in a graph.


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LMB Left mouse button. Main Launcher Main window (bar) in SeisWare. Many of SeisWare’s features can be found here. It is the menu that first opens when SeisWare is launched. Montage Editor Allows user to alter the print out appearance by placing objects and defining the size of those objects in a custom manner. Multi-Layer Seismic Viewer will display each segment selected on top of one another within the same viewer. Multi-Segment Seismic Viewer will display each segment selected side-by-side within the same viewer. Posting Placing text information on the Basemap. Can be applied to wells, seismic, horizons, and grids. Posting Tolerance This value is used to ensure that values are posted when they increase irregularly. For example if shot values are not exact numbers and the software may be attempting to post a value of 100, and the nearest shot is 100.05, this will still be posted if the posting tolerance is more than .05. Project List Text file that contains the information contained in Project Properties including the project location and description. Quick Iso Allows a user to select 2 horizons and create and isochron or amplitude on the fly which will not be saved to the database. Quick Iso results will be displayed with quotation marks around them. Raster A picture placed on the Basemap, typically a geotiff image. Ribbon Color on the Basemap. Ribbons may be 2D and 3D horizon information, grid information or well information. RMB Right mouse button. SEG-Y Viewer Window where SeisWare displays the header information of a SEGY file. Seismic Viewer A display of seismic in time. Shot Sequence Number Shot point numbering for a 2D, typically it increments by 0.5. Source A name used to denote where well information was obtained. Can represent a specific person or software package. Tops Formation depth value for a well.



Trace Sequence Number Crossline numbering for a 3D, typically displays as a saw tooth pattern in graph. Variable Size (Meters) Layer objects which are drawn the exact size specified. Objects will become larger or smaller as you zoom in and out. Wavelet Analysis Tool that will perform a cross correlation or Manhattan distance comparison using multiple wavelets. Also referred to as facies analysis. Working Set Working set files are the currently active version for a given line. These will be the default versions that appear on the map, or in any dialog.


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Advanced Interpretation 7.4

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