If a standby database is in a consistent state, you should be able to open the standby database into a read-only state to run reports.

Please refer to section 8 in the following document link to open the Standby in read-only mode using the Command Line:

https://dbvisit.atlassian.net/wiki/pages/viewpage.action?pageId=106135948#DbvisitStandbyCommandLineInterface(CLI)-8.OpenStandbyDatabaseRead-only

Please refer to section 8 in the following document link to open the Standby in read-only mode using the Central Console (GUI) by clicking on the Standby host:

https://dbvisit.atlassian.net/wiki/display/DS8QSG/Central+Console%3A+Managing+Databases#CentralConsole:ManagingDatabases-4.DatabaseStatus,Restart,StartandStop