Use of the V$PWFILE_USERS:

$pwfile_users view contains a list of all users who have been granted the SYSDBA or SYSOPER privilege.V$PWFILE_USERS columns  with details :

Column                       Description
USERNAME::This column contains the name of the user that is recognized by the password file.
SYSDBA::If the value of this column is TRUE, then the user can log on with SYSDBA system privilege.
SYSOPER ::If the value of this column is TRUE, then the user can log on with SYSOPER system privilege.
SYSASM::If the value of this column is TRUE, then the user can log on with SYSASM system privilege.

From 11g there is a new column in v$pwfile_users for the SYSASM privilege.

select * from v$pwfile_user;

*Use this query to check users for which password change to copy password file.
*Any user that is not appearing in above query o/p , its password change will automatically replicate.