Creating a database link from Oracle Cloud server to remote access database
In theory yes, you could set up such a link, but I'm not sure I'd advise it. You would need an Oracle Gateway server on your local network to bridge the connection. You will also need direct network connectivity from the cloud to your Gateway server, which means opening your local firewall to allow the inbound connection from the internet. It would imply that you have a pretty robust network/secure infrastructure to support something like that.

See here: https://blogs.oracle.com/datawarehousing/making-database-links-from-adw-to-other-databases 

or here: https://conferences.heanet.ie/assets/files/Thursday_B_11.00_Dick_Doyle_UCD.pdf