250.406—What additional safety measures must I take when I conduct drilling operations on a platform that has producing wells or has other hydrocarbon flow?
         You must take the following safety measures when you conduct drilling operations on a platform with producing wells or that has other hydrocarbon flow:
    
    
    
        
        (b) 
         You must shut in all producible wells located in the affected wellbay below the surface and at the wellhead when:
    
    
        
        (1) 
         You move a drilling rig or related equipment on and off a platform. This includes rigging up and rigging down activities within 500 feet of the affected platform;
    
    
    
        
        (3) 
         A mobile offshore drilling unit (MODU) moves within 500 feet of a platform. You may resume production once the MODU is in place, secured, and ready to begin drilling operations.