Reading audit records in Oracle
The audit records are written to the operating system's audit trail defined by the audit_file_dest parameter. You can change the format of to XML by changing the audit_trail parameter but the files will be still kept on the file system.
This due to security reasons since DBAs shouldn't be able to access those files if they are being audited.
You can play around with external tables or create a shell script for analyzing the files but there is no built in mechanism for analyzing the data.