Guidance on DNV's DRILL notation

OFFSHORE TECHNICAL GUIDANCEAnnualDrilling relatedstructuresComplete periodical• Visual inspection primaryload path members includinglifting eyes/pad eyes.Liftingarrangements forequipment• Spot-check NDT on main structural welds as deemedappropriate.• Load test as requiredWell control systemsAnnual Well control Complete periodical• Review of records ofmaintenance (e.g. pressuretest results, NDT reports,repair work);• Review records for functiontesting of the BOP using theaccumulators mounted on theBOP Stack;• Review records for functiontesting of the fail-safe valvesin the Choke & Kill linesmounted on the BOP.BOP stack*/General* incl. hydraulic hoses,shuttle valves, highpressure panels, etc.• Such major components will normally have the majoroverhauls carried out during the complete periodicalsurvey. Confirmation of recent major overhaul ofBOP components in presence of a DNV Surveyor tobe reviewed;• Complete function testing of the BOP-stack includingall preventers, connectors and fail-safe valves (usingthe accumulator system, not only the stack mountedaccumulators);• Leak/pressure test to demonstrate satisfactoryfunction of rams, annular elements, valve gates, C/Kconnections;• Testing should be carried out at low pressure (approx.200-300 psi) and then at max rated working pressure.(Note: For testing of the pipe rams and annularelement a suitable test tool should be used, suitablyanchored to the test stump);• MPI of all load bearing welds on the BOP guideframe;• Survey of BOP stack structural frame checkingevidence of excessive corrosion or damage.DET NORSKE VERITASAppendix AOTG-07