Editing Time/Depth Pairs (Synthetics)

In Insight, wells are converted from depth to time exclusively using Time/Depth pairs (checkshots), which are picked and edited in the Synthetics view.

Because the Synthetics view operates in time, it requires T/D pairs before you can do anything else. If you attempt to view a well in Synthetics that lacks T/D pairs, Insight will prompt you for two to start with. This then enables you to view your well data relative to your seismic which is usually recorded in TWT (ms). T/D pairs are displayed as horizontal blue lines on the time-depth track.

T/D pairs are usually acquired as part of a checkshot survey done at the same time as well logging. If you do not have T/D pairs from a checkshot survey, then you can manually define your own in the Synthetics view TVDSS-TWT track. When you manually specify a T-D pair, the depth axis is fixed and you manually specify the TWT you wish that depth to be converted to. This can be done at any depth on the well and, in doing so, you build up a vertical velocity profile which can be used to convert the entire well log to TWT.

If you are not the owner of the active set of T/D pairs, then you will not be able to edit them. To take ownership, or create your own set of T/D pairs, see Defining Time/Depth Pairs, Managing Well Components and Selecting Default Well Components.

Tip: You can undo or redo changes made in the current session by right-clicking in the panel and clicking Undo or Redo. In addition, you can undo/redo entire sessions worth of changes by clicking Undo/Redo in the T/D Pairs tab in the Configure Well window (see Managing Well Components).

Manually editing a T/D pair

A given T/D pair is fixed at a particular depth, and you can drag it to a new TWT.

  1. In the depth track, find the checkshot that you want to shift.
  2. Drag it up/down in the time column. You will not be able to drag it above or below a neighbouring checkshot.

Note: The implied interval velocity (shown by default as a blue line in the Vp track) updates interactively as you edit.

Bulk-shifting T/D pairs

  1. Select a range of checkshots by shift-clicking any two in the depth track (or right-click to Select All). Selected checkshots are displayed with red lines.
  2. Drag any of the selected checkshots to move them all at once.
  3. To clear the selection, right-click in the depth track and choose Clear selection.

Bulk-shifting by a specific amount

Bulk-shifting by a specific amount
  1. Select one or more checkshots by shift-clicking one or a range of checkshots in the depth track (or right-click to Select All).
  2. Beneath the depth track, type the amount (in ms) by which you want to move the checkshot(s).
  3. Click the up or down arrow to move the selected checkshots by the specified amount.

Add a checkshot

Add a checkshot
  1. To add a new T/D pair at the mouse location, right-click in the depth track and select Add checkshot. Remember that the checkshot will be fixed at a specific depth, and that you can edit the time by dragging it.
  2. To specify both the time and depth for the new checkshot, right-click and select Add manual checkshot.

Deleting checkshots

  1. In the depth track, right-click on the checkshot that you want to delete. You can also select a range of T/D pairs by holding down shift and right-clicking the checkshots.
  2. In the menu that appears, select Delete checkshot(s) to remove the selected checkshots.