Replication using Datagaurd to FAR DR We have already setup Oracle replication using Dataguard from a primary active site to a near DR site. The near DR is a passive site.

Is it possible to replicate from the Near DR (Passive) site to Far DR site using dataguard?
Yes it is possible.

Cascaded Redo Transport Destinations


  A cascaded redo transport destination (also known as a terminal
  destination) receives primary database redo indirectly from a standby
  database rather than directly from a primary database.
  
  A physical standby database that cascades primary database redo to one
  or more terminal destinations at the same time it is applying changes
  to its local database files is known as a cascading standby database.


More details at the above URL.