How to Survive a Rig Inspection: Part 15
In this series, our head of Rig Inspection Services Steven Lee shares tips on how operators and owners can get through rig inspections with flying colours – and which pitfalls to avoid! Mr Lee has more than a hundred rig inspections under his belt, from all parts of the world. In this chapter we turn our focus onto dynamic positioning systems, often referred to as mission critical systems.
Part 15: Dynamic Positioning Systems
An inspection team will want to see that the system is being well maintained and operated, with the appropriate dynamic positioning reference systems being used for the drilling rig’s operations.
One of the main focus areas of a DP inspection will be the DP operations manual, which will outline how the rig-specific operations are conducted and how the equipment should be used. Much like a marine operations manual, the DP operations manual will be a class approved document, in line with both the International Marine Contractors Association (IMCA) and the Marine Technical Society (MTS) guidelines and ultimately the International Maritime Organisation (IMO) resolutions. The rig inspection team will be looking to see that the procedures outlined in this document are being followed – typically, the completion of handover checklist, pre-arrival checklists, completion of annual and 5 yearly system tests etc.
It is becoming more and more common that drilling rigs conduct both annual trials and 5 yearly FMEA trials on a rolling basis rather than these being conducted as a single activity, for the obvious reason to maximise operational time during that period.
With the rolling schemes, these annual trials are usually split over a large number of individual tests, which in theory are all addressed over the course of the 12-month period. However, the reality of these rolling annual trials is often that a small number of individual tests are missed, either because they are time-consuming or difficult to complete.
A good rig inspection team will review all the completed tests over a number of years to ensure that if any tests have been missed, then this is not a recurring theme with the same tests being missed year after year.
Another area of focus for a rig inspection team is the suitability of the DP reference systems to the drilling location, ensuring that the reference systems installed are appropriate to the water depth and geographical location in which the rig will be operating.
DP systems are complex multi-redundant systems. Inspection teams will check to see if any modifications have been made, that these are appropriately documented and that the overall vessel’s redundancy concept has been maintained. This will often involve modifications to test programs to verify that the system’s integrity and redundancy are maintained.
A further area of consideration during a DP system inspection is that, in effect, a DP system is a large computer network, which like most computer systems is vulnerable to cyber-attacks. As such, this should be assessed during any DP system inspection looking at aspects of both local access and remote access cybersecurity, as well as software backup and control procedures.