Re: Teradata to Oracle Database Migration Tool for Free
Oracle have a migration workbench that they use to migrate customers from other databases. It works for the most common platforms like SQL Server and DB2 but I don't know if it works with Teradata. One problem is that you Teradata database data model should be customised and optimised for Teradata and not suitable for a direct migration to Oracle.
You could try reverse engineering your database model in a modelling tool such as ErWin, adjusting the model to suit Oracle and creating the table structure on Oracle. Then use an ETL tool or exports and imports to move the data between the two.