Quick guide to OPatch

http://docs.oracle.com/cd/E15586_01/doc.1111/e16793/opatch.htm

Create a folder /opt/oracle/patches
Copy there your patch zip file (p16266172_111150_Generic.zip)
unzip p16266172_111150_Generic.zip
cd /opt/oracle/patches/16266172
export MW_HOME=/opt/oracle/fmw11_1_1_5/
export ORACLE_HOME=/opt/oracle/fmw11_1_1_5/osb
shut down all wl servers
/opt/oracle/fmw11_1_1_5/oracle_common/OPatch/opatch apply -invPtrLoc /opt/oracle/fmw11_1_1_5/osb/oraInst.loc
restart the domain

I got an error "OPatch failed with error code 73", this because opatch could not find the /etc/config/actions.xml file.