Have you tried to patch your WebCenter environment and received the following error?
The OPatch version is not applicable for current OUI version.
OPatch failed with error code 19
The $ORACLE_HOME environment variable is set to the wrong location. This can occur due to having multiple Middleware Home locations on the environment, multiple Oracle products installed, or the variable inadvertently set to the wrong location.
If you are using OPatch from the default location, go one directory back.
Print the current directory.
Set the ORALCE_HOME environment variable to this directory.
Ex. export ORACLE_HOME=/u01/oracle/Middleware_Home