Critical maintenance for idle rigs

Article published in the Regulator | Issue 1: 2016

Current industry conditions have led to a situation where mobile offshore drilling units (MODUs) are sitting idle for long periods of time — a situation not seen for some years.

In some cases, rigs are being ‘cold stacked’; workers are transferred or released, the hatches are battened down and the rig is completely shut down. Other operators may choose to ‘ready stack’ or ‘warm stack’ their rigs such that although the rig is idle it is still operational. A ready stacked rig typically retains most of its maintenance crew and can deploy quickly if a client requires its services. In a ready stacked state, normal maintenance operations similar to those performed when the rig is active are continued by the crew so that the rig remains work ready. In either case, stacking a rig involves ‘storing’ the rig in a harbour, shipyard or designated holding area offshore. These MODUs are not within NOPSEMA’s jurisdiction and the authority does not have any regulatory role in operators’ management of the maintenance of idle MODUs.

Whether the operator suspends all maintenance while the rig is idle or has a modified maintenance plan is at its own discretion. When a MODU does return to NOPSEMA’s jurisdiction there are two principal issues of interest in this context:

1. Is the equipment fit for purpose and assuredly so?

2. Do the records in the maintenance system reflect (a) refurbishments or replacements that have taken place, and (b) do forward-looking records accurately reflect the required maintenance regime?

Two different approaches to these issues came to light during recent NOPSEMA inspections where two rigs had been idle for a lengthy period prior to starting work.

In the first instance, the computerised maintenance management system (CMMS) was kept operational although it was not being utilised. Much of the rig equipment had been stripped down and refurbished and in some cases replaced. When it came time for the rig to return to operations, the CMMS had a large backlog that had to be reviewed by the maintenance crew to ascertain if it was still applicable in light of the refurbishment and change-out of equipment. This approach added to the workload of the maintenance crew but was essential to ensure that no critical maintenance was missed. In the second instance, the CMMS was shut down. When the system was subsequently reactivated it automatically started scheduling maintenance from the reactivation date. The system had been shut down in 2014 and reactivated in 2015.

In the most extreme cases critical annual maintenance routines which were last conducted in 2013 were rescheduled for 2016. Some of these gaps were picked up by the experienced rig crew and others were picked up by virtue of a company requirement to have third party certification as evidence of maintenance. However, there was no assurance that all gaps were identified. This situation clearly represents a deficiency in the operators’ ability to demonstrate maintenance of critical control measures.

NOPSEMA recognises the fundamental importance of maintenance and maintenance management and it is one of the focus topics for inspection in the NOPSEMA’s annual operating plan for 2015-16. When a facility returns to NOPSEMA’s jurisdiction, NOPSEMA will examine how the operator has ensured the integrity of critical control measures to maintain the risk to offshore workforce to as low as reasonably practical.