Loading VSP data in SEG-Y Loader

Insight does not support VSP data specifically, but it can load the information for display. The challenge with VSP data is finding a useful way to present it. Note that significantly deviated well bores will have larger projection errors than straight-hole wells using these methods.

The approach varies depending on the type of data. All methods require VSP data as SEG-Y and use the SEG-Y Loader.

Corridor Stack (or other single trace)

SEGY Loader - Basic Settings window
  1. In the SEG-Y Loader, select to load 2D Lines (CMP) in Time domain.
  2. Select No to loading gathers.
  3. Click Next.

Selecting the SEG-Y Files

Select 2D SEG-Y Files
  1. Click to add a single SEG-Y containing one trace (e.g. corridor stack).
  2. Input the Survey Line Name as [YourWell]_VSP.
  3. Click Next.

Specify the byte locations of headers

Specify the byte locations of headers
  1. Confirm the Number of Samples and Sample Interval headers are set.
  2. Set the Common Midpoint (cmp) to a header containing the value 1 (e.g. 21 [int32]).
  3. Select the I will import navigation file(s) option.
  4. Click Next.

Filters

  1. Click Next to continue to Analysis.

Analysis

  1. Click Start to begin analysing traces.
    • Currently, the SEG-Y Loader will not detect any traces.
  2. Click Next and continue past any warnings.

Load Navigation Data Files

  1. Loading navigational data is optional. Click Next to skip this step.

Survey

  1. Select to Create a New Survey called [YourWell]_VSP.
  2. Click the entry in Lines.
  3. Add two rows in the box at the bottom section:
    • CMP: 1, SP: 1, X: Well top X, Y: Well top Y
    • CMP: 2, SP: 2, X: Well top X + 100, Y: Well top Y
      e.g. CMP: 1, SP: 1, X: 401366.42 Y: 8832348.16
  4. Click Next.

Note: The CMP range is based on the value of the CMP from the trace header, which is usually 1. If the CMP value from the trace header different, use the CMP range matching it. For example, if the CMP value is 10, use CMP: 10 and CMP: 11.

Output options

  1. At the Output Options section, type an Output Filename (e.g. [YourWell]_VSP-Corridor_Stack.dugio) and select a destination.
  2. Choose Stack as the volume's Class (Data Type).
  3. At the line, set the Step to 1.
  4. Click Next to begin writing the dugio volume.

Geograms (Synthetics, frequency based, 2-10 traces)

  1. In the SEG-Y Loader, select to load 2D Lines (CMP) in Time domain. Select Yes - Frequency to load frequency gathers.
  2. Click Next.

Select SEG-Y Files

  1. Add a single SEG-Y containing traces (e.g. geograms).
  2. Input the Survey Line Name as [YourWell]_VSP.
  3. Click Next.

Specify the byte locations of headers

  1. Confirm that the Number of Samples and Sample Interval headers are set correctly.
  2. Make sure that Common Midpoint (cmp) is set to a header containing the value 1 (usually 21 [int32]).
  3. For Ensemble Trace Number (cdpt), select a trace header containing a different value for each trace (e.g. cdpt, tracl, ep).
    For example, Ensemble Trace Number (cdpt): [Trace Header], 1, [int32]
  4. Then, select I will import navigation file(s).
  5. Click Next.

Filters

  1. You should not need to change anything here. Click Next to proceed to Analysis.

Analysis

  1. Click Start to begin analysing traces.
  2. In the Messages section, make sure that none of the traces are skipped.

Load Navigation Data Files

  1. Click Next to skip this step.

Survey

  1. Select to use an existing survey (or follow the directions above to Create a New Survey called [YourWell]_VSP).
  2. Click Next.

Output options

  1. At the Output Options section, type an Output Filename (e.g. [YourWell]_VSP-Synthetics_25-35-45Hz.dugio) and select a destination.
  2. Choose Stack as the volume's Class (Data Type).
  3. Click Next to begin writing the dugio volume.

Upgoing Survey (Many traces, single type, variable receiver time)

  1. In the SEG-Y Loader, select to load 2D Lines (CMP) in Time domain. Select Yes - Channel to load channel gathers.
  2. Click Next.

Select SEG-Y Files

  1. Add a single SEG-Y containing traces (e.g. upgoing).
  2. Input the Survey Line Name as [YourWell]_VSP.
  3. Click Next.

Specify the byte locations of headers

  1. Confirm that the Number of Samples and Sample Interval headers are set correctly.
  2. Make sure that Common Midpoint (cmp) is set to a header containing the value 1 (usually 21 [int32]).
  3. For Trace Sequence File (tracr), select a trace header containing the receiver elevation (e.g. gelev, cdpt).
    For example, Trace Sequence File (tracr): [Trace Header], 41, [int32]
  4. Then, select I will import navigation file(s).
  5. Click Next.

Filters

  1. You should not need to change anything here. Click Next to proceed to Analysis.

Analysis

  1. Click Start to begin analysing traces.
  2. In the Messages section, make sure that none of the traces are skipped. Observe "Channel" contains receiver elevations.

Load Navigation Data Files

  1. Click Next to skip this step.

Survey

  1. Select to use an existing survey (or follow the directions above to Create a New Survey called [YourWell]_VSP).
  2. Click Next.

Output options

  1. At the Output Options section, type an Output Filename (e.g. [YourWell]_VSP-UpgoingEnhanced.dugio) and select a destination.
  2. Choose Stack as the volume's Class (Data Type).
  3. Click Next to begin writing the dugio volume.

Displaying VSP data

You can use similar approaches (i.e. load the vsp traces as gathers) to include them in your project. By using appropriate section views (e.g. 2D gather view, Arbline view), you can get useful displays.

Consider using groups to overlay single traces from the VSP results on seismic data. Create an arbline that runs through the data and intersects the 2D line created for the VSP at the CMP=1 location.

If you encounter any problems, or if you have any questions, please contact our support team at [email protected].