Combining the earlier suggestions to determine your personal permissions (ie 'USER' permissions), then use this:
-- your permissions
select * from USER_ROLE_PRIVS where USERNAME= USER;
select * from USER_TAB_PRIVS where Grantee = USER;
select * from USER_SYS_PRIVS where USERNAME = USER;
-- granted role permissions
select * from ROLE_ROLE_PRIVS where ROLE IN (select granted_role from USER_ROLE_PRIVS where USERNAME= USER);
select * from ROLE_TAB_PRIVS where ROLE IN (select granted_role from USER_ROLE_PRIVS where USERNAME= USER);
select * from ROLE_SYS_PRIVS where ROLE IN (select granted_role from USER_ROLE_PRIVS where USERNAME= USER);