Depth stretching logs

Using the Depth Stretching form (1D MODEL > Mapping > Depth Stretching), you can perform TVD-based markers and log stretching from an existing well to a target well or wellbore section. In addition to stretching logs and markers, you can also map models from one well to another.

Specifying the input data

  1. Select the stretching mode. You can choose between Logs and Logs + Models. When you select Logs, the composite logs are stretched. When you select Logs + Models, the composite logs are stretched, and the following models:
    • NCT model
    • Custom trends
    • Zonation model
    • Lithology model
  2. Choose how to select the logs that are stretched. When you select Composite logs, only the composite logs from the source case are copied. When you select Specific logs, the Logs table is enabled, and you can select all the logs that you want to stretch. The table is populated with the logs from the source wellbore.
  3. When there are multiple cases listed in the Depth Stretching View, the multi-case settings section is enabled.
  4. Determine the multi case setup. When you select Log set (1), the algorithm will try to find the log with the same name from each source case that is different from the “main” source case. When you select Associated composite log (2), the algorithm will try to detect whether the stretched log is a composite log in the “main” source case, and if yes – it will take the corresponding composite log from every other source case if the naming search fails.
  5. After making all the selections, click the Execute button to map the selected logs and models to the target wellbore.
  6. Click OK to close the form.

It is recommended to go trough the 1D Model and Wellbore Stability workflows again, once a case has been stretched. This allows you to check and update the results for the stretched case. You can check the status of the various calculations in the mapped case by opening the data > 1DCase > Auto-Update Settings form. Red lock icons indicate calculations that need to be updated.

Note: In the case of composite log stretching, the algorithm will generate two logs on the target‑case side. One log will be a “service” log used to hold the stretched values for the target composite log (it will have a “<for composite>” substring in its name), and the second log will be the target composite log itself.