Hi,
I think the link provided (SAP on Oracle development update) do not answer the question
What kind of "export" are you talking about.
SAP "export" (R3LOAD)? yes, you can use heterogeneous system copies to upgrade the database.
Oracle "export" (DPUMP)? yes, your DB should be smaller so it does not takes for ever but it will not be supported by SAP, so you are on your own if you try that.
Note 1915302 - Database Software 12.1.0.2 Installation on Windows has information on the installation of the software, but you should also look at the upgrade guide