Another drilling contractor, Seadrill, recently put to the test DNV’s new standard for managing integrated software dependent systems. Wendy Laursen assesses the system’s scope for reducing software-related downtime on drilling units.
There are a limited number of technicians worldwide who can be called out to troubleshoot software integration and robotic control problems on drilling rigs, and when these units are delivered turnkey from the yard, it is difficult for owners to achieve the level of understanding they need for their own effective problem management, not only during commissioning but on an on-going basis.
‘With the diagnostics and remote access that is being built into our rigs now, it is really important that software integrity is flawless,’ says Steve O’Leary, technical services director at Seadrill. ‘A lot more attention needs to be paid to integrated systems because they can be a huge source of downtime. If things start to go wrong, and if you’ve got to try and learn about a system to troubleshoot, then it dramatically increases your mean time to repair. What should be a little five- or 10-minute nuisance fault (can) turn out to be a day and a half and a million dollars.’
Seadrill is an offshore deepwater drilling company that operates a fleet of 41 units including drillships, jackup rigs, semisubmersible rigs and tender rigs. Their latest generation newbuilds are highly automated and when software is integrated, care must be taken to ensure that the movements of components such as pipe handlers do not clash with other, equally-automated components.
Seadrill engaged Det Norske Veritas (DNV) to test the classification society’s recommended practices for managing systems with high levels of software integration. The practices were developed over several years before being adapted to maritime industries and published in 2008. This year, DNV promoted the recommended practices to an offshore standard and a voluntary class notation called Integrated Software Dependent Systems (ISDS).
Seadrill undertook a pilot project, applying the practices retrospectively to a recent newbuild to determine if the practices would have covered the gaps they felt occurred in the software integration process. DNV’s software engineering team in Houston meet with Seadrill staff and evaluated procedures and documentation. Although many of the units in Seadrill’s fleet are not classed by DNV, this software integration task falls outside the scope of mandatory class rules and could be supported without conflict by DNV. The service provided by DNV was of a high standard, O’Leary says.
‘They look at the system as an integrated whole and tend to know what to look for when they come out to check if it is working properly.’
Seadrill and DNV addressed commissioning, change management, crew competence and transparency issues. ‘Our strategy is to prevent software defects from getting deployed in the first place,’ O’Leary says. While individual components worked well, problems arose with missed handshakes and inconsistent parameters during commissioning.
The project addressed typical integration problems like limited local vendor support and long downtimes. One finding was that the rig crew had little or no involvement in the integration testing processes that could have built up their competence to support the system, and they relied on service engineers flown in from overseas. Naturally, it was also recognised that not all the expertise necessary to maintain every system can be kept continuously available onboard every rig.
‘The lack of technical documentation limited the understanding of what was being tested, and there was no good means of feedback when equipment design or functionality did not meet operational requirements,’ O’Leary says.
It was also difficult to assign problems to a particular vendor as some machines can have up to five vendor control systems involved in their operation. Some equipment manufacturers offered poor training and did not follow up to ensure their equipment was working as designed, and inadequate software revision control led to downtime and the loss of important upgrades. Documentation for fixes and upgrades generally lacked detail on what was being changed, why and how it should be tested.
‘Analysis that DNV has done indicates that application of our class notation methodologies can easily save $6 million by avoiding the delays caused by the need to re-work software,’ says Rolf Benjamin Johansen, director of operations at software integration for DNV maritime and energy. ‘This analysis was made for an advanced semisubmersible but is applicable to rigs as well. Equally important as the numbers themselves is the fact that these methodologies have been proven effective in the aerospace, telecommunications, defence and automotive industries.’ DNV continues their research and innovation activities to further develop and draw on the advances already made in these industries, before applying them to maritime and offshore applications.
A modern drilling rig can contain over a million of lines of computer code, the same amount as the latest Airbus A380 aeroplane. While existing class rules work to ensure a rig or ship is safe, they are not intended to ensure operability and efficiency, especially related to nonsafety critical systems, according to DNV. Software-related downtime can continue to be a problem throughout the life of an offshore unit as most software is designed with a three-year lifecycle, compared to the 20-25 year design life of the hardware. The situation becomes even more complex when dealing with large fleets using software from different vendors.
DNV’s notation focuses on how to set up and run a project and how to develop quality assurance processes that will last the lifetime of the vessel. ‘The class notation alone is not a silver bullet that will solve all software-related problems on drilling rigs, but it is an important part of the solution. The class notation provides a well-defined framework for the industry on how to work systematically with quality and performance assurance for software dependent systems,’ Johansen says.
The process typically starts when owners are specifying their requirements, either for a newbuild or an enhancement to an existing system. In collaboration with DNV specialists, the owner can assess suppliers to ensure they have the pre-requisites for delivering good quality software. Most particularly, focus is placed on the software integration service providers, and roles and responsibilities are defined for all parties involved. Methodologies are then put in place to ensure that relationships run smoothly.
‘A lot of people think that if you do testing at commissioning, everything will be okay because that is how they are accustomed to thinking about hardware. You do a factory acceptance test, and if it passes, then the equipment is ready. We believe that by following our recommended practices, owners are able to address potential problems earlier in the project, at a time when it is much cheaper to resolve any problems without causing critical delays,’ Johansen says.
Once a DNV-classed unit is operational and the different parties involved are able to continue to deliver at a level that reduces overall risk of system failure, the notation is awarded. The benefits are ongoing, Johansen says. ‘Our methodologies are not only applicable for the development project and commissioning. They are also applicable during operation in order to manage changes. We see a lot of software that goes into these systems is constantly being modified throughout the lifetime of the rigs.’
If a ‘copy and paste’ methodology is adopted for specifying future newbuilds, any errors can be propagated throughout the fleet with snowballing consequences, he says.
Johansen draws the comparison between software engineering and other engineering fields, such as welding. Risk is managed in welding by controlling the requirements for the qualification of welders and the procedures they should follow. This is combined with managing the physical properties of the weld through testing procedures such as x-ray. ‘Our notation does the same thing with software engineering by providing established practices on how to do the development and how to undertake quality assurance.’ Yet, despite the increasingly important role that software plays offshore, there is less focus than there should be on it, Johansen says.
‘Everyone has been relying heavily on the suppliers, but they don’t have a complete system overview. Owners and particularly system integrators need to play a much more active role to ensure software engineering is as good as other engineered components.’
After a period of on-site collaboration, Seadrill and DNV had planned and delivered recommended practice training, performed gap analysis and risk analysis to prioritise their findings and developed a plan of action. Ten major action areas were identified, seven relating to on-going operation and three to future newbuilds. Importantly, external support helped Seadrill to keep the initiative moving so that new practices were implemented and the company was better prepared for future newbuilds.
O’Leary values the practical and realistically achievable nature of the software management system established with DNV support. ‘It is a great tool to help guide ourselves through new systems and optimisations and we’ll definitely use it going forward. We want to change one of the software control systems on the rig for the riser tension and we’ll use the whole process from start to finish.’ OE
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