Required database permissions
There's no official documentation for Oracle (I don't think), but INSTALL.mysql.txt states you need the following permissions for MySQL in Drupal 7:

SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, INDEX, ALTER


I came across an INSTALL.oracle.txt on http://drupalcode.org, but I can't vouch for it's accuracy. It says to run the following with regards to permissions:

grant dba, create any trigger, drop any table, select any table, select any sequence, create user to drupal identified by drupal;
grant connect, resource to drupal with admin option;
alter user drupal default tablespace users temporary tablespace temp;


Show both of those files to your DBA, it should be enough for him to go on.