How to audit table permissions as a non-DBA
You need to connect to schema_1 to run this query.
There is a helpful view user_tab_privs. If you are on 11g or higher, then 
listagg function can show the list of other privileges. Otherwise remove row with listagg form query

select table_name, grantee , 
        max(sel) sel, max(ins) ins , max(upd) upd, max(del) del,
        case when max(other_privs) is not null then 'other' end other_privs,
        listagg(other_privs,',') within group (order by other_privs) as list_of_other_privs
 from 
 (select table_name, grantee, 
        case when privilege='SELECT' then 'y' end sel, 
        case when privilege='INSERT' then 'y' end ins, 
        case when privilege='UPDATE' then 'y' end upd, 
        case when privilege='DELETE' then 'y' end del,
        case when privilege not in ('SELECT', 'INSERT','UPDATE','DELETE') then privilege end other_privs 
   from user_tab_privs
 ) 
  group by table_name, grantee 
  order by table_name, grantee