Oracle 11gR2 - Limits on Materialised View replication between databases
This sounds like a job for Change Data Capture (CDC), which allows you to (among other possibilities) ship your archivelogs from the OLTP database to the reporting one, mine them for the changes, then query the changes out, ignoring any you don't want (e.g., changes of type 'D' for DELETE), and using whatever process you might devise apply those changes to your reporting tables.

I have no idea how well CDC would do with a ruleset encompassing 4700 source tables from another database. I've never used it for more than about 50 tables myself.

FYI, there are licensing-related limits on CDC. The full feature set is only available on Enterprise Edition.