I am by no means an Expert when Oracle Semantic Technology, but I would definately look at Oracle Text. There is some integration with SPARQL if you want to search for a value in the semantic database. However, only the 'CONTAINS' function is supported (I'm not sure if there are additional functions on the way or not). There is some customization you can do when you create the Context Index.
Take a look at both the Semantic Technologies Developer's Guide section 1.6.5 (http://docs.oracle.com/cd/E11882_01/appdev.112/e25609/sdo_rdf_concepts.htm#CHDJACII), and the Oracle Text Reference (http://docs.oracle.com/cd/E11882_01/text.112/e24436.pdf)