Review the procedures for configuring Replication Agent for Oracle.
Primary Oracle Database Configuration for Replication
Configure the primary Oracle database for replication and to ensure that the Oracle redo log data is not overwritten before it is read by the Replication Agent.
Creating the Replication Agent Instance
A single installation of the Replication Agent can support replication from multiple databases, however, one Replication Agent instance is needed for each Oracle database that is to be replicated.