Geomodeling > Technical Tips > Tip #4 - Synthetics In VisualVoxAt


Technical Tips: Tip #4

Synthetics In VisualVoxAt



VisualVoxAt allows geoscientists to generate synthetics in several different ways. As a result, geoscientists can develop their own workflow around synthetics. This geophysical tip outlines the ways to build synthetics, and you, the geoscientist, can choose the way that best suits you!

Step One - QC Your Data

Using the Well Property dialog box (Figure 1) you can check the log datum of your well and edit it if necessary. The log datum can also be edited in the Well Data Manager, but cannot be edited in the Synthetic Tool.



Figure 1

If your well is deviated, you can check the deviation in the Well Property dialog box (Figure 2). Here you can adjust the type of deviation file and edit all the columns.



Figure 2

Using the Project Manager you can check your well log types and define your alias table (Figure 3). The alias table is editable, so you can type in the well log names.



Figure 3

Well logs can be checked using the Well Log viewer and edited using the Well Log Curve Information dialog box (Figure 4). It is always good to copy your logs before editing. This is easy to do -right-click on the log and use the copy tool.



Figure 4

You can check the datum by viewing the Project Setting dialog box (Figure 5). You can then apply this datum to the Time Depth spreadsheet.



Figure 5

Step Two - Time-Depth Curves

You can import a time-depth curve or checkshot data or generate a time-depth curve based on the sonic log. Always check the units of your data when you import. In VisualVoxAt, you can import an ASCII file or you can copy and paste the time-depth spreadsheet. When you have the time-depth curves in your project, you can check them by looking at a spreadsheet view or at a curve view. Both these dialog boxes are editable (Figure 6).




Figure 6

The three ways to generate a time-depth curve in VisualVoxAt are:

  • Right-click on the name of the sonic log and click "Calculate TD curve" (Figure 7).
  • Batch-calculate the time-depth using the Synthetic Tool dialog (Figure 8).
  • Calculate on one well in section view using the synthetic tool (Figure 9).



    Figure 7: Calculate time-depth using right-click menu in Project Manager



    Figure 8: Batch-calculate time-depth using Synthetic Tool dialog. Use this process on all wells or on selected wells



    Figure 9: Calculate time-depth on a single well using the Seismic Synthetic Tool dialog from section view

    Generating Synthetics

    Now that we have all our wells and support data imported and quality checked, it is time to generate a synthetic. This can be done one well at a time from section view, or by batch, and all the synthetics for an area can be computed and tied to tops or horizons.

    From the section view, we can select the synthetic tool and use the Parameters tab to select the sonic curve, the density data, and the time-depth data, and to upscale the log based on impedance (Figure 10).



    Figure 10

    Using the Wavelet tab, we can select the type of wavelet and adjust the phase (Figure 11). You can choose from four types of wavelets, or import a wavelet.



    Figure 11

    The batch process is much the same as the single well process. You simply choose all wells or a group of wells, and then select the parameters. To initiate the batch process from the Project Manager, right-click on "Wells" and select Synthetics. You can also initiate it from the Tools menu or from any well subfolder that you generated. Once generated, you can view your synthetics in the Project Manager in the Well tab. Each well that has a synthetic generated will have an icon for synthetic in the log list.



    Figure 12: The dialog box for batch processing

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