You need to deploy it in WC_Portlet managed server. (WSRP)
Register your portlet as producer in WebCenter creating a connection to your WSRP portlet in WebCenter Portal / Spaces application.
Add this portlet to Resource Catalog and add it to a page with Oracle Composer to consume it.
Is your JSR 168 portlet WSRP 1.0 or 2.0 enabled? WebCenter can only integrate WSRP enabled portlets. You cannot deploy your war file to the portal itself. You need to deploy the war file to the portlet container and register the producer as a WSRP producer in webcenter. Therefore, the portlet needs to have the valid web service endpoint to act as a WSRP endpoint.