Your profession (Petroleum) implies the pipeline is for oil..
I will suggest you to develop in-house company standard for in service inspection ,and probably should address; pipeline repair,pipeline protection, Corrosion Control , row and site maintenance
,pipeline pigging,valve maintenance requirements, SCADA and system automation ....etc...
You may look to API 570,API 579-1 FFS-1, for specific items..
Good luck..