overflow vs well over

overflow is a noun but well over is not a noun.

Word	Noun	Adjective	Verb	Adverb
overflow	Yes	No	Yes	No
well over	No	No	Yes	No

As verbs, overflow and well over are synonyms defined as:

Other synonyms of overflow include brim over, overrun, run over.

overflow (noun)	well over (noun)
a large flow
the occurrence of surplus liquid (as water) exceeding the limit or capacity

overflow (verb)	well over (verb)
overflow with a certain feeling	flow or run over (a limit or brim)
flow or run over (a limit or brim)