You can use this SQL statement to get the SID, SERIAL# of the current session:

SELECT s.sid,
s.serial#,
spid,
TRIM (s.machine) machine,
TRIM (s.module) module,
status
FROM v$session s, v$process p
WHERE paddr = addr AND module IS NOT NULL
ORDER BY 1, 2

Then with sqlplus Run

ALTER SYSTEM KILL SESSION 'sid,serial#';

Or by shell commnad:

kill -9 spid.

Regards,

Mahmoud Morsy.