I need to log to a remote Oracle database engine or a database engine that is not included in the TNSNAMES.ORA file.

Use the following as the Database name:

(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=MyHost)(PORT=MyPort)))(CONNECT_DATA=(SERVER=DEDICATED)(SERVICE_NAME=MyOracleSID)))

As example for a system with a computer name GWDESK and the Oracle database name OPCDb:

(DESCRIPTION=(ADDRESS_LIST=(ADDRESS=(PROTOCOL=TCP)(HOST=GWDESK)(PORT = 1521)))(CONNECT_DATA=(SERVER= DEDICATED)(SERVICE_NAME=OPCDb)))