Refractor 8.1 User Guide

Transcription

1 Refractor 8.1 User Guide Copyright 2016, All rights reserved.

2 Table of Contents Preface...1 Conventions Used in This Guide...1 Where to Find Information...1 Technical Support...2 Feedback...2 Chapter 1 Introducing Refractor Interface...3 Title Bar...4 Menu Bar...4 File Menu...5 Trace Menu...6 Pick Menu...7 TX Curve Menu...7 Analysis Menu...8 Section Menu...8 Options Menu...9 Window Menu...9 Help Menu...9 Display Window...10 Toolbar...11 Status Bar...11 Chapter 2 Processing Seismic Data...12 Importing Seismic Data...13 Loading Seismic Data...17 Checking Geometry...19 Displaying Seismic Data...20 Display Settings...20 Trace View...21 Overlaid Traces...21 Editing Seismic Data...23 Frequency Filter...23 Gain Control...25 Single Trace Scaling...25 Reverse Polarity...27 Trigger Delay Correction...27 Inputting Elevation Data...29 Chapter 3 Picking First Breaks...30 Creating a TX Curve File...31 Opening a TX Curve File...31 Making First Breaks Easier to Be Identified...32 Zooming In Seismic Data...32 Adjusting the Display Gain...32 Refractor 8.1 User Guide i

3 Overlaying Traces...33 Picking First Breaks...34 Adjusting First Break Picks...36 Saving First Break Picks...37 Supporting 3rd Party Picks Formats...38 Merging TX Curves...39 Chapter 4 Assigning Layers and Phantoming TX Curves...40 Assigning Layers...41 Phantoming TX Curves...43 Chapter 5 Interpreting TX Curves...46 Interpreting with GRM...47 Interpreting with Delay Time Method...52 Interpreting with ABC Method...54 Interpreting with Intercept Time Method...56 Chapter 6 Displaying Color Section...57 Smoothing Color Section...58 Setting Color Grades...59 Changing Display Parameters...61 Showing Locations...62 Plotting Well Data...63 Exporting Color Section...65 Chapter 7 Plotting Curves...66 TX Curve Options...67 Curve Display...69 Chapter 8 Outputting Results...71 Saving Results in Text Files...72 Export Results...73 Refractor 8.1 User Guide ii

4 Preface Thank you for choosing Refractor the Seismic Refraction Data Processing Software in Geogiga Seismic Pro. Using Refractor, you can: Import seismic data while assigning geometry and integrating files. Edit seismic data with frequency filter and gain control. Correct trigger delay according to the time or surface velocity. Pick first breaks with a trace magnifier. Interactively assign first arrivals to layers. Automatically or manually phantom time-distance curves. Interpret time-distance curves with intercept time method, delay time method, ABC method, or generalized reciprocal method (GRM). Generate geological section with editable lithologic symbols. Conventions Used in This Guide The conventions used in this guide are given below: Bold Represents keystrokes, menu items, window names, or fields. Italic Uses for file names, directory names, and emphasis as well. Courier Denotes the text to enter. Where to Find Information The following list explains what you can find in this guide: Chapter 1 introduces the Refractor interface. Chapter 2 describes how to input, display, and process seismic data. Chapter 3 provides the details on picking first breaks. Chapter 4 talks about the layer assignment and phantom. Chapter 5 shows how to interpret time-distance curves. Chapter 6 talks about the color section.

5 Chapter 7 discusses the curve plotting. Chapter 8 explains how to output results. If you are a first-time user, first read the Getting Started with Geogiga Seismic Pro which can be accessed by clicking the Getting Started command under the Help menu in the Geogiga Seismic Pro Launchpad. Technical Support If you have questions, need additional assistance, or encounter a problem, please contact Technical Support using the information given below: Telephone: support@geogiga.com Web: Feedback To help us improve the future documentation, we want to know any corrections, clarification or further information you would find useful. When you contact us, please include the following information: The title of the documentation you are referring to The version of the application you are using Your name, company name, phone number, and address Please send us your comments at sales@geogiga.com. Preface 2

6 Chapter 1 Introducing Refractor Interface The Refractor interface has five parts as shown in figure 1-1: Title Bar Menu Bar Toolbar Display Window Status Bar The following will explain these parts in detail. Title Bar Menu Bar Toolbar Display Window Status Bar Figure 1-1:The Refractor interface Chapter 1 Introducing Refractor Interface 3

7 Title Bar The Title Bar shows the time-distance (TX) curve filename. When you pick first breaks, adjust picks, assign layers, or phantom TX curves, a * symbol will appear at the end of the filename to remind you to save the TX curve file. Menu Bar The Menu Bar has following menus: File Menu Trace Menu Pick Menu TX Curve Menu Analysis Menu Section Menu Options Menu Window Menu Help Menu When you click one of the menu names, a drop-down submenu appears and displays a list of related commands. Chapter 1 Introducing Refractor Interface 4

8 File Menu The submenu under the File menu, as shown in figure 1-2, contains following commands: New Load seismic data and create a TX curve file. Open Open a TX curve file with the option of loading seismic data. Import Seismic Assign geometry in multiple files (one file per shot) and integrate these files. Save Save the TX curve file. Save As Save the TX curve file in the binary or text format with a new name. Save Seismic Save seismic data file. Save Seismic As Save seismic data file with a new name. Save Depth Output depth in a text file. Save Velocity Output velocity in a text file. Edit Elevation Input elevation data. Merge TX Curves Merge TX curves saved in different files. Print Print an image plotted in the Display Window. Save Image Save an image plotted in the Display Window. Close Close the TX curve and seismic data files. Exit Exit Refractor. Chapter 1 Introducing Refractor Interface Figure 1-2: The File submenu 5

9 Trace Menu The submenu under the Trace menu, as shown in figure 1-3, contains the commands listed as follows: Show Toggle the visibility of trace view. All Records Switch the trace view between a single record and all records. Display Change the display of seismic data including plot type, display gain, display range, display scale, and annotations. Geometry Check and redefine geometry. Filter Filter seismic data with Butterworth or Ormsby filter. Gain Control Scale seismic data with gain control. The types of gain control include AGC, trace balance, and time variant scaling. Scale Up Increase the data amplitude of a selected trace by 2 times. Scale Down Reduce the data amplitude of a selected trace by 2 times. Reverse Polarity Reverse the data polarity of a selected trace. Trigger Delay Correction Correct the trigger delay according to the time or surface velocity. Undo Erase changes done to seismic data. Redo Reverse the Undo. Chapter 1 Introducing Refractor Interface Figure 1-3: The Trace submenu 6

10 Pick Menu The submenu under the Pick menu, as shown in figure 1-4, contains following commands: Settings Change the pick settings, such as the option of manual or automatic picking. Trace Magnifier Magnify a selected trace to make the first break easier to be identified. Overlay Traces Display two seismic records on a same plot for comparison of first break picks. Previous Shot Display previous shot record. Next Shot Display next shot record. Figure 1-4: The Pick submenu TX Curve Menu The submenu under the TX Curve menu, as shown in figure 1-5, contains the following commands: Assign Layer & Phantom Assign layers and phantom TX curves. Intercept Time QC Check layer assignment with the intercept time method. Curve Display Set the display of TX curves including axis, gridlines, background, and fonts. Curve Options Choose the visibility of TX curves. Chapter 1 Introducing Refractor Interface Figure 1-5: The TX Curve submenu 7

11 Analysis Menu The submenu under the Analysis menu, as shown in figure 1-6, contains the commands given below: GRM / Delay Time / ABC Interpret TX curves with GRM, Delay Time, or ABC method. Intercept Time Interpret TX curves with Intercept Time method. Figure 1-6: The Analysis submenu Section Menu The submenu under the Section menu, as shown in figure 1-7, contains the commands given below: Show Plot results as color section. Grid Smooth the color section. Grade Define color grades and symbols. Display Settings Change the display settings, including scale, annotation, and title. Display Wells Plot well data on color section. Show Locations Plot the shot and receiver locations in color section. Export Export the section to DW Tomo as an initial model or to Seismapper for plotting in 3D fence. Chapter 1 Introducing Refractor Interface Figure 1-7: The Section submenu 8

12 Options Menu The submenu under the Options menu, as shown in figure 1-8, contains the following commands: White Background Switch the background color between white and black when plotting curves. Full Window Toggle the display of full window for curve plotting. Gridlines Change the visibility of gridlines for curve plotting. Figure 1-8: The Options submenu Vertical Layout Set the curve display view in horizontal or vertical layout. Window Menu The submenu under the Window menu, as shown in figure 1-9, contains the following commands: Toolbars Change the visibility of Toolbars. Statusbar Toggle the visibility of the Status Bar. Figure 1-9: The Window submenu Help Menu The submenu under the Help menu, as shown in figure 1-10, contains commands listed as follows: Manual Open the User Guide. About View the information related to Refractor and the computer system memory. Figure 1-10: The Help submenu Chapter 1 Introducing Refractor Interface 9

13 Display Window The Display Window varies depending on the operating status. For example, in the picking status, the left is the Trace View, and the right is the TX Curves View. To adjust the view sizes, simply drag the separator bar as shown in figure The Trace View is a dockable window. You can undock or dock it by double-clicking the Trace View title bar as shown in figure After the Trace View is undocked, you can drag it to change the location of the window. TX Curves View Double click the Trace View to dock or undock the trace view window Trace View Separator Bar Figure 1-11: The Display Window in the picking status To toggle the visibility of the Trace View, click the Show command under the Trace menu. To switch the Trace View between a single record and all records, click the All Records command under the Trace menu. Chapter 1 Introducing Refractor Interface 10

14 Toolbar As shown in figure 1-12, the button icons on the Toolbar correspond to the commonly used commands under the menus. To run a command, click its related button icon. Figure 1-12: Icons on the Toolbar Status Bar On the Status Bar, you will see the information related to commands, seismic data, or curves when moving the mouse cursor over the interface. Chapter 1 Introducing Refractor Interface 11

15 Chapter 2 Processing Seismic Data This chapter covers most of the operations related to seismic data including: Importing seismic data Loading seismic data Checking geometry Displaying seismic data Editing seismic data Inputting elevation data Chapter 2 Processing Seismic Data 12

16 Importing Seismic Data If the multiple shot data are saved as per shot per file, you need to import seismic data first. The purpose of importing seismic data is to: Assign geometry in multiple files (one file per shot). Integrate multiple files after geometry assignment. To import seismic data, open the Geometry Assignment and Files Integration dialog box by clicking the Import Seismic command under the File menu. On the dialog box as shown in figure 2-1: (1) Select the Group 1 name from the Geometry Definition Group list box. The group concept is designed to make geometry assignment quicker and easier. Normally, a group should have similar features in order to use the filling rule described in the step (4). (2) Enter numbers in the Auxiliary Traces field, such as 1, 2, 6-9. Leave the field blank if there are no auxiliary or dummy traces in each shot record. (3) Add multiple files to the Files table by clicking the Add button under the Files table. (4) Input the relevant geometry information for each shot under the following columns in the Files table. Shot No. the shot number which can be any unique number Shot(x) the shot X coordinate 1st Rcvr(x) the 1st receiver X coordinate Rcvr(dx) the receiver interval in X direction To quickly assign the geometry, utilize the filling rule in the Assign drop-down list box which can be accessed by clicking the arrow button next to the Assign button. The filling rule, applied to a selected column, includes: Extrapolation Based on the values in the first two cells, the values in the other cells are linearly extrapolated. Repetition The other cells are filled out with the same value as that in the first cell. Chapter 2 Processing Seismic Data 13

17 Filename The other cells are filled out according to the file naming rule and the value in the first cell. Current Column The values in all cells under the current column are loaded from a text file. Assign All with the First The other rows are filled out with the same values as those in the first row. For example, if the receiver interval is uniform, enter the value in the first cell under the Rcvr(dx) column, then click the arrow button next to the Assign button and select the Repetition name from the drop-down list box to automatically fill out the other cells under that column. (5) Click the View button to open the Geometry dialog box as shown in figure 2-2. On the dialog box, you can review the layout chart, check the receiver coordinates, and input or load irregular receiver coordinates from a text file. To input irregular receiver coordinates, enter the coordinates in the relevant cells in the Receiver Locations table. If some receivers have constant intervals, enter the first two receivers' X coordinates in the relevant cells, and then click the Auto Fill button to automatically fill out the other cells below these cells. For instance, a shot array, as shown in figure 2-2, has 12 geophones with 960m at 1st receiver, 10m spacing of 1~6 receivers, 5m spacing of 7~12 receivers, and 20m spacing between 6th and 7th receivers. You can: First, enter 960 and 970 in the 1st and 2nd cells, and then click the Auto Fill button. Secondly, enter 1030 and 1035 in the 7th and 8th cells, then select the 7th and 8th rows by holding down the Shift or Ctrl key while clicking the 7th and 8th row headers, and finally click the Auto Fill button. After inputting the coordinates, you can save them in a text file by clicking the Save button. To set all coordinates to 0, click the Clear button. To load receiver coordinates from a text file, click the Load button. The coordinates are saved as per row per receiver in the text file, such as, Chapter 2 Processing Seismic Data 14

18 To change the display of layout chart on the Geometry dialog box, click the arrow button next to the Display label below the layout chart, then a drop-down list box will appear. From the drop-down list box, you can: Choose whether to display all spreads and use the fixed display range. Set the display of layout chart including background, gridlines, and annotations. Change the plotting colors for shots and receivers. (6) Add a new geometry definition group by clicking the Add button next to the Geometry Definition Group list box. Then, repeat step (2)~(5). To remove a geometry definition group, select the group name and click the Remove button next to the Geometry Definition Group list box. (7) Enter the output filename in the Output field. (8) Click the Integrate and Load Data button to assign geometry and integrate files, then load seismic data and create a TX curve file. Or click the Integrate button to only assign geometry and integrate files. Later, click the New or Open command under the File menu to load seismic data. To save the geometry definition in raw seismic data files, click the Save button. The above steps are illustrated in figure 2-1. Chapter 2 Processing Seismic Data 15

19 Figure 2-1: The Geometry Assignment and Files Integration dialog box Figure 2-2: Inputting irregular receiver coordinates in step (5) Chapter 2 Processing Seismic Data 16

20 Loading Seismic Data After importing seismic data, you can load the data by clicking the New or Open command under the File menu. When you click the New command, the Open Seismic File dialog box appears. On the dialog box as shown in figure 2-3: (1) Select the seismic data file. (2) Specify the TX curve filename in the Output file field. To change the filename, type in the field or click the Browse button next to the field. (3) Click the Open button to load seismic data and create a TX curve file. Figure 2-3: The Open Seismic File dialog box Chapter 2 Processing Seismic Data 17

21 When you click the Open command under the File menu, the Open TX Curve File dialog box appears. On the dialog box as shown in figure 2-4: (1) Choose the TX curve file. (2) Select the Seismic option, and then click the Browse button to locate the seismic data file. (3) Click the Open button to open the TX curve file while loading seismic data. After loading seismic data, check the geometry and set the data display to make first breaks easier to be identified. Figure 2-4: The Open TX Curve File dialog box Chapter 2 Processing Seismic Data 18

22 Checking Geometry To check the geometry after loading seismic data, click the Geometry command under the Trace menu to open the Geometry dialog box as shown in figure 2-5, where you can review and modify the geometry. To review the geometry, choose a record by clicking the Previous Shot or Next Shot button icon on the Toolbar or clicking the left mouse button on the top horizontal annotations in the Trace View, then you will see the layout chart and the coordinates are accordingly updated. There are two ways to modify the geometry: Input or load from a text file. For details on how to input or load coordinates, refer to Step (5) in Importing Seismic Data described earlier. Figure 2-5: The Geometry dialog box After changing the geometry, click the Apply button to overwrite the coordinates in the file header for the chosen shot record. To set the current geometry for all shot records, click the Apply All button. To save the geometry changes in the seismic file, click the Save Seismic or Save Seismic As command under the File menu. Chapter 2 Processing Seismic Data 19

23 Displaying Seismic Data After loading seismic data, you can change the display settings, set the visibility of trace view, and overlay traces. Display Settings To set the display of seismic data, open the Trace Display dialog box by clicking the Display command under the Trace menu. On the dialog box as shown in figure 2-6: Choose the plot type and adjust the display gain. Specify the display range of seismic data and view the sample rate. Define the scale factors. Change the annotation settings. Select to plot the trace graph. To learn about this dialog box, read Chapter 4 in Getting Started with Geogiga Seismic Pro. Figure 2-6: The Trace Display dialog box Chapter 2 Processing Seismic Data 20

24 Trace View To toggle the visibility of the Trace View, click the Show command under the Trace menu. To switch the Trace View between a single record and all records as shown in figure 2-7, click the All Records command under the Trace menu. Single Record All Records Figure 2-7: Switching the Trace View between a single record and all records Overlaid Traces When a single record is displayed in the Trace View, the view can be overlaid with another record as shown in figure 2-8. Figure 2-8: Overlaying traces To overlay traces, open the Overlay Record dialog box as shown in figure 2-9 by clicking the Overlay Traces command under the Pick menu. On the dialog box, you can: Chapter 2 Processing Seismic Data 21

25 Toggle the visibility of the overlay by clicking the Overlay check box. Choose the overlaid record by clicking the record number in the Overlay list. Set the display of overlay color. Figure 2-9: The Overlay Record dialog box Chapter 2 Processing Seismic Data 22

26 Editing Seismic Data The following lists the ways to edit seismic data in Refractor: Filter data with frequency filter. Apply different types of gain control. Scale up or down a single trace. Reverse the polarity of a single trace. Correct trigger delay. Frequency Filter The seismic data can be filtered with low-pass, high-pass, band-pass, band-reject, or notch filters. Two types of filters are available: Butterworth filter and Ormsby filter. To apply frequency filtering on data, open the Frequency Filter dialog box by clicking the Filter command under the Trace menu. On the dialog box as shown in figure 2-10: (1) Set the display of amplitude spectrum by: Dragging the Max Frequency slide bar to adjust the frequency display range. Clicking the arrow button next to the Display button to choose whether to display the Power or Amplitude spectrum in db, or clicking the Display button to change the spectrum view settings such as colors, gridlines, etc. (2) Update the amplitude spectrum. By default, the spectrum of the 1st record is shown. To plot the spectrum of a different record, choose a record by clicking the Previous Shot or Next Shot button icon on the Toolbar or clicking the left mouse button on the top horizontal annotations in the Trace View, and then click the Refresh button. To plot the spectrum of a trace, click the Selected Traces radio button, then choose a trace by clicking the left mouse button on the top horizontal annotations in the Trace View, and finally click the Refresh button. To normalize the spectrum plotting, click the Normalize button. (3) Select the Butterworth filter or Ormsby filter by clicking the drop-down list box next to the Filter label. Chapter 2 Processing Seismic Data 23

27 (4) Choose the Low Pass, High Pass, Band Pass or Band Reject by clicking the dropdown list box next to the Type label. When the Band Reject type is chosen, select whether to use notch filter by clicking the Notch check box. (5) Decide whether to apply a window function by clicking the Window check box. Here, the Hanning window is used. (6) Set the parameters of Pass and Slope (or Cut for the Ormsby filter) by: Horizontally dragging the relevant control nodes marked as green dots on the gate curve in the spectrum window. Or entering values in the relevant fields and then clicking the Set button. (7) Choose the data Traces to be Filtered among the All Records, Current Record, and Selected Traces options. The All Records option will be invisible when a single record is displayed in the Trace View. (8) Click the Apply button to filter seismic data. To check the effect of filtering or tune the filter parameters, click the Undo and Redo button icon on the Toolbar. Figure 2-10: The Frequency Filter dialog box Chapter 2 Processing Seismic Data 24

28 Gain Control To apply gain control on seismic data, open the Gain Control dialog box by clicking the Gain Control command under the Trace menu. On the dialog box as shown in figure 2-11: (1) Select the types of gain among the following options and set the relevant parameters: AGC(Automatic gain control). Trace Balance including RMS, Quantile, and Mean Subtraction. Scale including Time, Exp, Power, and Constant. (2) Choose the data Traces between the All Records and the Current Record option. (3) Click the Apply button to scale seismic data. To check the effect of gain or determine the types of gain, click the Undo and Redo button icon on the Toolbar. Figure 2-11: The Gain Control dialog box Single Trace Scaling To make first breaks easier to be identified, the Trace RMS is chosen as the default display Scale Type on the Trace Display dialog box as shown in figure Before scaling a single trace, set the display Scale Type to one of the following options: Global Maximum Global RMS Chapter 2 Processing Seismic Data 25

29 Global Average Histogram Figure 2-12: Choosing the display Scale Type Next, click the Settings command under the Pick menu to open the Pick Settings dialog box as shown in figure 2-13 and deselect the Pick option. Figure 2-13: Deselecting the Pick option Chapter 2 Processing Seismic Data 26

30 Finally, select a single trace by clicking the left mouse button on the top horizontal annotations in the Trace View, then scale up or down the trace by: Clicking the Scale Up or Scale Down button icon on the Toolbar. Or holding down the Shift key while pressing the right arrow key( ) or the left arrow key( ) on the keyboard. To cancel the scaling done to the trace, click the Undo button icon on the Toolbar. Reverse Polarity To reverse the polarity of a single trace, select a trace by clicking the left mouse button on the top horizontal annotations in the Trace View, and then: Hold down the Shift key while pressing the P key. Or click the Reverse Polarity command under the Trace menu. To cancel the change, click the Undo button icon on the Toolbar. Trigger Delay Correction To correct trigger delay, open the Trigger Delay Correction dialog box as shown in figure 2-14 by clicking the Trigger Delay Correction command under the Trace menu. Figure 2-14: The Trigger Delay Correction dialog box On the Trigger Delay Correction dialog box: (1) If the correction is applied after the picking of first breaks, turn on the With First Breaks option to shift both seismic data and picks. Chapter 2 Processing Seismic Data 27

31 (2) Select the rule of correction by clicking the Time or the First Break radio button. If the Time option is selected, enter the delay time in milliseconds in the text field next to the Time radio button. You can also click the left mouse button in the Trace View to set the time value in the text field if the Pick option the Pick Settings dialog box is turned on. If the First Break option is selected, enter the surface velocity in the Surface Velocity field. You may choose this option when the trigger delay is different for each record and the surface velocity is constant, for example, in marine survey. Make sure that first breaks are picked before choosing this option. (3) Choose the Trace Range between the All Records and the Current Record option. (4) Click the Apply button to correct the trigger delay. To cancel the correction, click the Undo button icon on the Toolbar. To reverse the Undo, click the Redo button icon on the Toolbar. After editing seismic data, click the Save Seismic or Save Seismic As command under the File menu to save the changes in the seismic data file. In Refractor, you can edit seismic data with: Frequency filter Gain control Single trace scaling Reverse polarity Correct trigger delay For more editing functionalities, such as: Scale up or down multiple traces Reverse polarity of multiple traces Swap traces Shift a single trace vertically Mute seismic data Resample seismic data Please refer to the Front End User Guide. Chapter 2 Processing Seismic Data 28

32 Inputting Elevation Data Refractor allows variable surface. You can load the elevation data anytime before interpreting TX curves. To input elevation data, open the Elevation Input dialog box by clicking the Edit Elevation command under the File menu. On the dialog box as shown in figure 2-15, (1) Input elevation data from a text file by clicking the Load button. The text file has two columns as shown below with 1 st column for X coordinates and 2nd column for elevations: -5, 5 0, 5 6, 4 33, 0 70, 12 If elevation data is not saved in a text file, go to step (2). (2) Enter the X coordinates and elevations in the text area below the X, Z Coordinates label. The input values are normally separated by a comma or space. You can also use the Ctrl-C and Ctrl-V keys to copy and paste the elevation data from other text editors or Windows Excel. To save elevation data in a text file, click the Save button. (3) Click the OK button to apply and save elevation data in the TT curve file. Figure 2-15: The Elevation Input dialog box Chapter 2 Processing Seismic Data 29

33 Chapter 3 Picking First Breaks This chapter covers the following topics: Creating a TX curve file Opening a TX curve file Making first breaks easier to be identified Picking first breaks Adjusting first break picks Saving first break picks Supporting 3rd party picks formats Merging TX curves Chapter 3 Picking First Breaks 30

34 Creating a TX Curve File A TX curve file, saving first break picks and interpretation parameters, is created by: Clicking the Integrate and Load Data button on the Geometry Assignment and Files Integration dialog box as shown in figure 2-1. The TX curve filename is same as that in the Output field but with an extension of tx. Or clicking the New command under the File menu to open the Open Seismic File dialog box as shown in figure 2-3, where the TX curve filename can be specified. Opening a TX Curve File To open a TX curve file, click the Open command under the File menu. Seismic data can also be loaded along with a TX curve file as shown in figure 3-1. Figure 3-1: Opening a TX curve file with seismic data Chapter 3 Picking First Breaks 31

35 Making First Breaks Easier to Be Identified To make first breaks easier to be identified, you can: Zoom in seismic data Adjust the display gain Expand the Trace View window Change the display scale type Apply gain control Scale up a single trace Overlay traces The first two methods are commonly used. The last method is often used for shear waves. Zooming In Seismic Data To zoom in the display of seismic data, click the Zoom In button on the scrollbar in the Trace View window as shown in figure 3-2. Figure 3-2: Zooming in seismic data Adjusting the Display Gain To adjust the display gain, drag the Display Gain slide bar on the Trace Display dialog box as shown in figure 3-3. Chapter 3 Picking First Breaks 32

36 Figure 3-3: Adjusting the display gain Overlaying Traces In order to clearly identify first breaks on shear waves, you can overlay the traces triggered from two directions as shown in figure 3-4. For details on how to overlay traces, refer to Displaying Seismic Data in Chapter 2. Figure 3-4: Overlaying shear wave traces Chapter 3 Picking First Breaks 33

37 Picking First Breaks Before picking first breaks, click the Settings command under the Pick menu to open the Pick Settings dialog box and select the Pick option as shown in figure 3-5. Figure 3-5: The Pick Settings dialog box There are two ways to pick first breaks in the Trace View window: Manually Automatically The Manually option is the default choice. To pick first breaks manually: (1) Select the Manually option on the Pick Settings dialog box. (2) Click the left mouse button on a seismic trace or drag the left mouse button over multiple traces. To pick first breaks automatically: (1) On the Pick Settings dialog box, select the Automatically option, and then Enter the maximum jump in milliseconds in the Max Jump field or click the arrow button next to the field. Chapter 3 Picking First Breaks 34

38 Choose whether to use the velocity as a guide in the automatic picking procedure by clicking the Velocity check box. If this option is selected, enter the average apparent velocity in the text field next to the check box. To check the apparent velocity, click the Test Velocity radio button, then drag the left mouse button along the first break events on seismic data in the Trace View window as shown in figure 3-6. The velocity value shown on the Status Bar is updated accordingly. Choose whether to use the phase of an event as a guide in the automatic picking procedure by clicking the Phase check box. If the Phase option is selected, enter the phase width in milliseconds in the Wavelet Width field or click the arrow button next to the field. (2) In the Trace View window, click the left mouse button on a seismic trace where the first break is clearly identified. After that, first breaks are automatically picked based on this pick. After picking first breaks, you can adjust or delete picks. Figure 3-6: Testing apparent velocity in the Trace View window Chapter 3 Picking First Breaks 35

39 Adjusting First Break Picks The picks can be adjusted simultaneously or individually. There are two ways to adjust all picks on a shot record simultaneously: If the Manually option is selected, turn on the Shift All Picks option, then move the mouse cursor over the picking line on a trace and drag the picking line vertically. This will constantly shift all picks. If the Automatically option is selected, move the mouse cursor over the picking line on a trace and drag the picking line vertically. This will automatically adjust all picks. To adjust an individual pick: (1) Select the Manually option and turn off the Shift All Picks option. (2) Select a trace by clicking the left mouse button on the trace or pressing the right arrow key ( ) or the left arrow key ( ) on the keyboard. (3) Move the mouse cursor over the picking line on the selected trace and then drag the picking line vertically. To adjust a pick precisely, open the Trace Magnifier window by clicking the Trace Magnifier button icon on the Toolbar. In the window as shown in figure 3-7, drag the red picking line vertically to adjust the pick, while the pick's time and amplitude are changed accordingly.. The buttons at the bottom of the Trace Magnifier window are used to magnify the plotting, toggle the transparent background, and change the visibility of the zero line. Figure 3-7: The Trace Magnifier window Chapter 3 Picking First Breaks 36

40 To delete picks, hold down the Ctrl key while clicking the left mouse button on a selected trace or hold down the Ctrl key while dragging the left mouse button over multiple traces. To pick or adjust first breaks at a different shot record, click the Previous Shot or Next Shot button icon on the Toolbar, and then repeat the picking or adjusting operations. During the picking, saving the TX curve file frequently is recommended. Saving First Break Picks The first break picks can be saved as binary format or text format. The binary file contains picks, elevation data, layer assignment, phantom, and interpretation parameters, while, the text file only includes picks and elevation data. Saving the picks as binary format is always recommended. To save picks as binary format, click the Save or Save As command under the File menu. To save picks as text format, click the Save As command under the File menu, then select the TX Curve text files option from the Files of type drop-down list box on the Save TX Curves As dialog box as shown in figure 3-8. Figure 3-8: Saving picks as text format After saving the TX curve file, you can open it later by clicking the Open command under the File menu. The picks file saved as text format can also be loaded in DW Tomo for refraction tomography. Chapter 3 Picking First Breaks 37

41 Supporting 3rd Party Picks Formats Most of the 3rd party picks formats are supported. To open a 3rd party picks file: (1) Click the Open command under the File menu, the Open TX Curve File dialog box appears. (2) On the dialog box as shown in figure 3-9, choose the 3rd Party picks option from the Files of type drop-down list box, then select a filename and click the Open button. Refractor automatically recognizes the picks format, loads the picks and saves them in a file which has the same filename but with an extension of tx. Figure 3-9: Opening a 3rd party picks file Chapter 3 Picking First Breaks 38

42 Merging TX Curves The normal steps are to import seismic data and then pick first breaks. However, you can also load each shot file individually, pick first breaks, and then merge the picks files. To merge TX curves saved in the individual files: (1) Open the TX Curve Files Integration dialog box by clicking the Merge TX Curves command under the File menu. (2) On the dialog box as shown in figure 3-10, enter a filename in the Output File Name field, then click the Add button to add TX curve files in the TX Curves file list box, and finally click the OK button. To remove a file from the list, select the filename and then click the Remove button. To show the file path, turn on the Show Path option. To change the list order, select a filename and then click the Up or Down button, or click the Sort Ascending or Sort Descending button. The list can have any orders, since the integration depends on the shot location not the list order. Figure 3-10: The TX Curve Files Integration dialog box Merging TX curves should be done before layer assignment and phantom. Chapter 3 Picking First Breaks 39

43 Chapter 4 Assigning Layers and Phantoming TX Curves Normally, you need adjust first break picks, assign layers, and phantom TX curves back and forth. To make the operations easier, Refractor has put the options of assign and phantom together on the Assign Layer and Phantom dialog box. To open the Assign Layer and Phantom dialog box, click the Assign Layer & Phantom command under the TX Curve menu. The dialog box varies with different options as shown in figure 4-1 and 4-3. The following talks about how to assign layers and phantom TX curves with this dialog box. Chapter 4 Assigning Layers and Phantoming TX Curves 40

44 Assigning Layers All the first break picks are set to Layer 1 by default. To assign layers, select the Assign option on the Assign Layer and Phantom dialog box as shown in figure 4-1, and then: (1) Choose a layer number from the Layer List box on the dialog box. (2) In the TX Curves View, choose a pick by clicking the left mouse button at a point on a TX curve, and then, Assign multiple picks to the layer by dragging the left mouse button from that point along the TX curve. Assign the pick to the layer by holding down the Ctrl key while clicking the left mouse button at that point on the TX curve. Make the pick invalid (that is, assign it to the null layer) or valid by holding down the Ctrl key while clicking the right mouse button at that point on the TX curve. (3) Repeat step (1)~(2) to assign layers on all TX curves. Figure 4-1: The Assign Layer and Phantom dialog box with the Assign option Chapter 4 Assigning Layers and Phantoming TX Curves 41

45 To check the layer assignment: Open the Intercept Time dialog box as shown in figure 4-2 by clicking the Intercept Time QC command under the TX Curve menu. On the dialog box, The velocity (V) and thickness (H) of each layer are calculated by the Intercept Time method. The thickness will be marked as? for the inverse velocity or incomplete stratum. The TX curve, the velocities, and the thicknesses are updated simultaneously with the layer assignment. To save the velocities and thicknesses at the current shot in a text file, click the Save button. Display seismic data by clicking the Show command under the Trace menu. On the display of seismic data, you still can adjust or delete a pick. Figure 4-2: Checking layer assignment with Intercept Time method After completing the layer assignment, phantom TX Curves. Chapter 4 Assigning Layers and Phantoming TX Curves 42

46 Phantoming TX Curves The purpose of phantom is to prepare for the GRM, the Delay Time method, and the ABC method by generating the complete forward and reverse TX curves. To phantom TX curves, select the Phantom option on the Assign Layer and Phantom dialog box as shown in figure 4-3, and then: (1) Decide the Forward and Reverse base shot location by click the Base Shot button as shown in figure 4-4. The base shot should have all layers assigned. (2) Select a layer number from the Layer List box. (3) Choose the Both option, and then click the Auto Phantom button to automatically phantom the TX curves based on the chosen layer. To phantom TX curves only in one direction, select the Forward or Reverse option. To see the animation of automatic phantom, select the Animated option and then set the speed of animation. (4) Repeat step(2)~(3) to complete the automatic phantom on all layers. To manually phantom TX curves, skip step (2)~(4), simply select a TX curve in the TX Curves View, then hold down the Ctrl key while dragging the curve or pressing the up arrow key ( ) or the down arrow key[ ]. To adjust the phantom, select a TX curve in the TX Curves View, then press the up arrow key ( ) or the down arrow key[ ]. To check the phantom: Turn on the Check Reciprocal Time option. Press the Preview button. Chapter 4 Assigning Layers and Phantoming TX Curves 43

47 Figure 4-3: The Assign Layer and Phantom dialog box with the Phantom option Figure 4-4: Choosing the base shot for phantom Chapter 4 Assigning Layers and Phantoming TX Curves 44

48 After checking the phantom, you may decide to: Interpret TX curves. Adjust or delete some picks. Reassign layers, or make some picks invalid or valid. In order to adjust picks or reassign layers, clear the phantom first. To clear the phantom: (1) Select a layer number from the Layer List box. (2) Click the Reset button. (3) Repeat step (1)~(2). After clearing the phantom, adjust picks on seismic data, then select the Assign option and reassign layers on TX curves. Once the layer assignment is done, go back to the Phantom option and phantom TX curves. Repeat the procedure if necessary. Next, save the results of layer assignment and phantom in the TX curve file by clicking the Save or Save As command under the File menu, and then start to interpret TX curves. Chapter 4 Assigning Layers and Phantoming TX Curves 45

49 Chapter 5 Interpreting TX Curves This chapter explains how to interpret TX Curves with the following methods: Generalized Reciprocal Method (GRM) Delay Time Method ABC Method Intercept Time Method The first three methods require the complete forward and reverse TX curves prepared by phantom. Chapter 5 Interpreting TX Curves 46

50 Interpreting with GRM To interpret TX curves with the GRM, open the Interpretation Settings dialog box by clicking the GRM / Delay Time /ABC command under the Analysis menu, and then select the GRM option on the dialog box as shown in figure 5-1. Figure 5-1: The Interpretation Settings dialog box with the GRM option Chapter 5 Interpreting TX Curves 47

51 On the Interpretation Settings dialog box as shown in figure 5-1: (1) Choose the type of Surface Velocity between the Average and Segment option. If the Average option is selected, click the = button to average the surface velocities calculated with the Intercept Time method and then display the average velocity in the field next to the = button. You can also manually input an average velocity in the field next to the = button. To allow a varying surface velocity, select the Segment option and then click the >> button to open the dockable Surface Velocity Definition window. In the window as shown in figure 5-2, define the segments by holding down the Ctrl key and clicking the left mouse button at the locations where the TX curves of the 1 st layer change sharply. To adjust the definition, drag the vertical line horizontally. After that, the surface velocities in different segments are updated with the Intercept Time method and then displayed in the location ~ velocity table. You can manually input the surface velocities in the location~velocity table and then click the Apply button to update the plotting and calculation. If the layer assignment or picks are modified, click the Update button to refresh the TX curves of the 1st layer shown in the Surface Velocity Definition window. Figure 5-2: Defining the segments of surface velocities Chapter 5 Interpreting TX Curves 48

52 (2) Determine the Spacing between two picks on a TX curve used in the calculation and turn on or off the Extrapolate TX Curve option. The default spacing equals to the minimum receiver interval. The linear interpolation is applied if the receiver interval is larger than the specified Spacing. The Extrapolate option extends TX curves along the seismic profile. (3) Choose the GRM Approximate or the GRM Average method. The GRM Approximate method supposes all layers can be detected in depth section, while, the GRM Average method accommodates undetected layers by using average velocities to determine the depth without reference to the actual layers. To see whether undetected layers exist, compare the Observed and the Calculated optimum XY values in the Optimum XY Analysis table. If the values do not agree, then undetected layers are indicated and you need use the GRM Average method. (4) Analyze the optimum XY values in the Optimum XY Analysis table. The optimum XY values are the key parameters in the GRM. Normally, there are two approaches to determine the optimum XY value: Observation of XY values This approach is the inspection of the velocity analysis and time-depth functions calculated for a range of XY values. The optimum XY value corresponds to the smoothest velocity analysis function and the roughest time-depth function as shown in figure 5-3. To determine the observed optimum XY values, specify the range of XY values by entering the values at relevant cells in the Min, Inc, and Max column, and then click the Apply button. Afterwards, the observed optimum XY values are shown at the relevant cells in the Observed column. To view the velocity analysis functions or the time-depth functions in the Display Window, turn on the Velocity Analysis option or the Time-depth Curves option, then click the layer number in the left column. To show the residual velocity analysis functions, turn on the Velocity Analysis option and then the Residual option. The residual velocity curves highlight the velocity variations and the smoothest curve correlates with the optimum XY value as shown in figure 5-3. Chapter 5 Interpreting TX Curves 49

53 Calculation of XY values. This approach is the direct calculation from the velocities and thicknesses which are determined by the GRM for XY=0. After you define the range of XY values in the Min, Inc, and Max column and then click the Apply button, the calculated optimum XY values are shown at the relevant cells in the Calculated column. Finally, compare the Observed and Calculated optimum XY values and decide the optimum XY values used in GRM, and then enter them at the relevant cells in the In Use column and click the Apply button to generate the depth and velocity sections. Figure 5-3: Determining the optimum XY value according to the velocity analysis, the residual velocity analysis, and the time-depth functions (XYOptimum = 20m) (5) View the depth section and the velocity section in the Display Window by turning on the Depth option and the Velocity Section option. To set the plot of depth section, click the Plot... button next to the Depth option. Chapter 5 Interpreting TX Curves 50

54 (6) Identify the velocity variation on the velocity or the residual velocity analysis curves if necessary. The velocity variation may exist if the slope of the velocity or residual velocity analysis curve for the optimum XY value changes sharply. For example, the velocity variation is indicated when the slope of the residual velocity curve for XYoptimum = 20m suddenly changes from upward to downward at the location of 175m as shown in figure 5-4. To specify the velocity variation at a location, double-click the left mouse button at the location on the velocity or the residual velocity analysis curves. Afterwards, a vertical line appears on the curves and the velocity section is updated. To adjust the location, drag the vertical line horizontally. To cancel the defined velocity variation, move the mouse cursor over the vertical line and then hold down the Ctrl key while clicking the left mouse button. Figure 5-4: Identifying velocity variations on the residual velocity analysis curve for XYoptimum = 20m Chapter 5 Interpreting TX Curves 51

55 Interpreting with Delay Time Method To interpret TX curves with the Delay Time method: open the Interpretation Settings dialog box by clicking the GRM / Delay Time /ABC command under the Analysis menu, and then select the Delay Time option on the dialog box as shown in figure 5-5. Figure 5-5: The Interpretation Settings dialog box with the Delay Time option Chapter 5 Interpreting TX Curves 52

56 On the Interpretation Settings dialog box as shown in figure 5-5: (1) Choose the type of Surface Velocity between the Average and Segment option. See the instructions on how to set the surface velocity described previously in Step (1) when Interpreting with GRM. (2) Determine the Spacing between two picks on a TX curve used in the calculation and turn on or off the Extrapolate TX Curve option. The default spacing equals to the minimum receiver interval. The linear interpolation is applied if the receiver interval is larger than the specified Spacing. The Extrapolate option extends TX curves along the seismic profile. (3) Click the Apply button to generate the depth section and the velocity section. (4) View the depth section and the velocity section in the Display Window by turning on the Depth option and the Velocity Section option. To set the plot of depth section, click the Plot... button next to the Depth option. To view the forward and reverse delay time curves, turn on the Forward Delay Time option and the Reverse Delay Time option. Chapter 5 Interpreting TX Curves 53

57 Interpreting with ABC Method To interpret TX curves with the ABC method, open the Interpretation Settings dialog box by clicking the GRM / Delay Time / ABC command under the Analysis menu, and then select the ABC option as shown in figure 5-6. Figure 5-6: The Interpretation Settings dialog box with the ABC option Chapter 5 Interpreting TX Curves 54

58 On the Interpretation Settings dialog box as shown in figure 5-6: (1) Choose the type of Surface Velocity between the Average and Segment option. See the instructions on how to set the surface velocity described previously in Step (1) when Interpreting with GRM. (2) Determine the Spacing between two picks on a TX curve used in the calculation and turn on or off the Extrapolate TX Curve option. The default spacing equals to the minimum receiver interval. The linear interpolation is applied if the receiver interval is larger than the specified Spacing. The Extrapolate option extends TX curves along the seismic profile. (3) Click the Apply button to generate the depth section and the velocity section. (4) View the depth section and the velocity section in the Display Window by turning on the Depth option and the Velocity Section option. To set the plot of depth section, click the Plot... button next to the Depth option. Chapter 5 Interpreting TX Curves 55

59 Interpreting with Intercept Time Method The Intercept Time method assumes the planar layers. It does not require complete forward and reverse TX curves. To interpret TX curves with the Intercept Time method, open the Intercept Time Method dialog box by clicking the Intercept Time command under the Analysis menu. On the Intercept Time Method dialog box as shown in figure 5-7: (1) Choose to use All TX Curves, or only TX Curves with Full Layers by clicking the relevant options. (2) View the depth section and the velocity section in the Display Window by turning on the Depth option and the Velocity Section option. To plot the elevation, turn on the Elevation option. Figure 5-7: The Intercept Time Method dialog box In the interpretation, you can set the plotting of curves in any view of the Display Window. For instructions, please refer to the Curve Display in Chapter 7. After interpreting TX curves, save the interpretation parameters in the TX curve file by clicking the Save or Save As command under the File menu. Next, show the results in color section. Chapter 5 Interpreting TX Curves 56

60 Chapter 6 Displaying Color Section After interpreting the TX curves with the GRM, the Delay Time method, or the ABC method, display results in color section as shown in figure 6-1 by clicking the Show command under the Section menu. Figure 6-1: Displaying results in color section The following discusses how to: Smooth color section. Set color grades. Change display parameters. Show locations. Plot well data. Export velocity section. Chapter 6 Displaying Color Section 57

61 Smoothing Color Section To smooth the color section, open the Section Gridding dialog box by clicking the Grid command under the Section menu. On the dialog box as shown in figure 6-2: (1) Select the Smoothing option. (2) Choose the smoothing method between the Median and the Mean option. (3) Specify the smoothing radius by clicking the arrow button next to the Radius field or entering a value in the Radius field. (4) Click the Apply button. Figure 6-2: The Section Gridding dialog box On the Section Gridding dialog box, the maximum depth to be displayed in the color section can also be defined in the Maximum Depth field. Chapter 6 Displaying Color Section 58

62 Setting Color Grades To modify the color grades, open the Section Grade Definition dialog box as shown in figure 6-3 by clicking the Grade command under the Section menu. Figure 6-3: The Section Grade Definition dialog box On the Section Grade Definition dialog box: (1) Enter the grade values in the cells under the Value column. For reference, the original data range is shown above the table. (2) To plot the section with colors, select the Color option and then change a grade color by double clicking the cell filled with the color under the Color column. (3) To plot the section with symbols, select the Symbol option, and then double click a cell under the Symbol column and choose a symbol from the drop-down list box. (4) Click the Apply button to update the display with the defined settings. After defining the values, colors, and symbols, save the settings in a file by clicking the Save button. The grade file can be loaded anytime with the Load button. Chapter 6 Displaying Color Section 59

63 To edit predefined symbols, click the Edit Symbol button to open the Symbol Editor dialog box as shown in figure 6-4, and then : Edit a symbol by selecting a symbol name from the Symbol List box, then clicking or dragging the left mouse button to draw or the right mouse button to erase on the grids in the Edit panel, finally clicking the Update button. Design the filling pattern of a symbol, as shown in the Sample panel, by selecting a symbol name from the Symbol List box, then turning on or off the Shift or Skip option, finally clicking the Update button. Rename a symbol by selecting a symbol name from the Symbol List box, and then changing the name in the Name field, finally clicking the Update button. Add a symbol by clicking the Add button and then editing the symbol. Delete a symbol by selecting a symbol name from the Symbol List box and then clicking the Remove button. Click the Save button to save the symbols in the g3symbols.sym file under the C:\Users\<username>\.geogiga directory. These symbols are shared by all applications in Geogiga Seismic Pro. Figure 6-4: Editing symbols on the Symbol Editor dialog box Chapter 6 Displaying Color Section 60

64 Changing Display Parameters To modify the display parameters, open the Section Display Settings dialog box as shown in figure 6-5 by clicking the Display Settings command under the Section menu. Figure 6-5: The Section Display Control dialog box On the Section Display Settings dialog box: Set the display scale under the Scale label by deselecting the Auto option and then entering values in the X and Y fields. The image size, shown in the relevant non-editable fields, is updated accordingly. The allowed maximum size of image depends on the Windows system and the available memory in your computer. When the image size is larger than the Display Window size, the scrollbar will appear. Chapter 6 Displaying Color Section 61

65 Change the annotations of axes under the X or Y Axis label by deselecting the Auto option and then entering values in the relevant Major and Minor fields. To modify the starting coordinate of annotations, enter a value in the relevant Start field. To define the decimal places of annotations, enter a value in the relevant Decimal Places field or click the arrow button next to the field. To reverse the color section, select the Reverse option. Specify the type of tick mark by clicking the Tick Mark combo box and then selecting an option among the None, Inside, Outside, and Cross options from the drop-down list. Toggle the visibility of colorbar by clicking the Colorbar check box. If the Colorbar option is selected, click the Vertical check box to display the colorbar vertically or horizontally. If sections are filled with colors and symbols, click the Value check box to annotate the colorbar with data values or symbol names. To specify the decimal places of annotations for colorbar, enter a value in the Decimal Places field under the Colorbar check box or click the arrow button next to the field. Display the title by selecting the Title option and then entering the name in the field next to the option. To update the display with the defined settings, click the Apply button. Showing Locations To turn on or off the annotation of shot and receiver locations on a color section, click the Show Locations command under the Section menu. Chapter 6 Displaying Color Section 62

66 Plotting Well Data Well data can be plotted on a velocity section as shown in figure 6-6. Figure 6-6: Plotting well data on a velocity section To display well data, click the Display Wells command under the Section menu to open the Input Well Data dialog box. On the dialog box as shown in figure 6-7: (1) Click the Add button, and then input the well name under the Name column in the Well List. (2) Enter the well location and the starting depth of the well in the Location and Starting Depth fields. (3) Input the depths of well data under the Depth column and select the lithologic symbol from the Lithologic Symbols list to describe the layers. (4) Repeat steps (1)~ (3) to add more wells. To remove a well from the well list, click the Remove button. To save the input of well data in a text file, click the Save button. The well data can be loaded from the text file by clicking the Load button. Chapter 6 Displaying Color Section 63

67 (5) Click the Apply button to plot well data in color section. To cancel the display of well data, deselect the Show option. To specify the width for the display of wells, enter a value in the Width field or click the arrow button next to the field. Figure 6-7: Inputting Well Data Chapter 6 Displaying Color Section 64

68 Exporting Color Section To export the velocity section to DW Tomo as an initial model or to Seismapper for plotting in 3D fence: (1) Click the Export command under the Section menu, then the Export Section dialog box appears. (2) On the Export Section dialog box as shown in figure 6-8, Select Horizon(*.hrz) from the Files of type drop-down list box to export the results to DW Tomo. Or select XZV data(*.xzv) from the Files of type drop-down list box to export the results to Seismapper. Then change the export filename in the File name field and finally click the Save button to export the color section. Figure 6-8: The Export Section dialog box This chapter has talked about how to smooth color section, set color grades, change display parameters, and export color section. The next describes the plotting of curves. Chapter 6 Displaying Color Section 65

69 Chapter 7 Plotting Curves This chapter introduces the options to plot TX curves, and then discusses the display settings applied to all kinds of curves. Chapter 7 Plotting Curves 66

70 TX Curve Options There are several options to display the TX curves. To change the plotting options, open the TX Curve Options dialog box as shown in figure 7-1 by clicking the Curve Options command under the TX Curve menu. Figure 7-1: The TX Curve Options dialog box On the TX Curve Options dialog box, select to: Plot the original TX curves by clicking the Original check box. If the Original option is selected, click the Current or All radio button to display the TX curves generated at current or all shot location(s). The phantomed TX curves will be plotted if the Phantomed option is turned on. The composite TX curves are used in the interpretation. To plot composite TX curves during interpretation, select the Composite option. Chapter 7 Plotting Curves 67

71 Show the TX curves assigned for current layer or all layers by clicking the Current or All radio button below the Layers label. Plot the TX curves collected in the forward, reverse, or both direction(s) by clicking the Forward, Reverse, or Both radio button. Label layers, plot regression line or show shot locations by clicking the Layer Label, Regression Line, or Shot Location check boxes. Indicate receivers by turning on the Receiver Indicator option. The view point size of receivers on TX curves can be defined in the text field next to the Size label. Synchronize the display of Trace View and TX Curve View by clicking the Auto Set Time Range with Trace View check box. If this option is turned on, the time range of TX curves will be automatically updated when the zoom button in the Trace View is clicked. Chapter 7 Plotting Curves 68

72 Curve Display To modify the display of curves including TX curves, depth section, velocity section, velocity analysis curves, and time-depth curves: (1) Open the Curve Display dialog box by clicking the Curve Display command under the TX Curve menu (2) Move the mouse cursor over a curve view in the Display Window, and then click the left mouse button to activate the view. (3) On the Curve Display dialog box as shown in figure 7-2, Define the curve display range and change the visibility of gridlines. Change the annotation settings and choose the background color. (4) Click the Apply button to update the display of curves. To learn about the Curve Display dialog box, please read Chapter 5 in Getting Started with Geogiga Seismic Pro. Figure 7-2: The Curve Display dialog box Chapter 7 Plotting Curves 69

73 For convenience, the following commonly used commands on the Curve Display dialog box are added in the submenu under the Options menu: White Background. To switch the background color between white and black. Full Window. To plot curves with or without annotations. Gridlines. To toggle the visibility of gridlines. The Vertical Layout command under the Options menu is to vertically or horizontally layout the curve views during the interpretation of TX curves. Chapter 7 Plotting Curves 70

74 Chapter 8 Outputting Results After the interpretation of TX curves, results can be: Printed as images. Saved as images. Saved in text files. Exported to DW Tomo as an initial model or to Seismapper for plotting in 3D fence. The following talks about the last two options. To learn how to print results or save results as an image, view Chapter 6 in Getting Started with Geogiga Seismic Pro. Chapter 8 Outputting Results 71

75 Saving Results in Text Files Results including depths and velocities can be saved in text files. To save depths in a text file: (1) Click the Save Depth command under the File menu to open the Select Depth File Name dialog box. (2) On the dialog box as shown in figure 8-1, enter a name in the File name field and then click the Save button. Figure 8-1: The Select Depth File Name dialog box To save velocities in a text file, click the Save Velocity command under the File menu and follow the instructions similar to those on saving depths. Chapter 8 Outputting Results 72

76 Export Results To export results to DW Tomo as an initial model or to Seismapper for plotting in 3D fence: (1) Plot the color section by clicking the Display command under the Section menu. (2) Click the Export command under the Section menu to open the Export Section dialog box as shown in figure 8-2. On the dialog box, Select Horizon(*.hrz) from the Files of type drop-down list box to export the results to DW Tomo. Or select XZV data(*.xzv) from the Files of type drop-down list box to export the results to Seismapper. Then change the export filename in the File name field, finally click the Save button to export results. Figure 8-2: The Export Section dialog box Here, the results must be generated from the GRM, the Delay Time, or the ABC method and displayed in the color section. Chapter 8 Outputting Results 73