The development of subsea controls over the past 30 years, and trends for the future, were reviewed as part of a subsea technology day held in Aberdeen last month by Aker Solutions, and attended by some 150 industry professionals. Four generations of subsea control modules, which have helped shape the North Sea industry in the last 30 years, were also on show. Meg Chesshyre reports.
The Aker Solutions subsea control systems portfolio encapsulates 30 years of development work done under the Ferranti offshoot FSSL, Aker Kvaerner and latterly Aker Solutions nameplates, but the past five to 10 years has seen a rapid increase in control module complexity.
According to Derek Robertson, senior manager with the company's systems solutions group, key drivers going forward include a more robust failure reporting, analysis and collective action system, otherwise known as FRACAS. With different applications such as subsea processing and boosting emerging, there are much heavier demands on instrumentation. He admits that in the past the UK controls company had been product focused in terms of its technology development, but says it is now trying to align itself more closely with the subsea production system organisation in Oslo and take account of the wider client view.
In terms of execution, Aker Solutions is looking to have more modular architecture and standard building blocks to meet fast-paced market demand. Robertson stresses the importance of keeping abreast of opportunities to provide more life cycle services, condition monitoring, real time flow assurance and reservoir modelling. Post-Macondo safety issues had taken time to roll down into the supply chain, he notes, but now the Norwegian Petroleum Directorate, among others, are setting higher safety integrity goals, especially with regard to well intervention systems.
'We tended to have a limited portfolio of products in the 1980s, then we moved into a deliver all things for all men mode, and produced many different variants to all our clients,' recalls Robertson. 'The current focus is on a narrowing back to a more configurable product.'
He likens the development of control modules over the last 30 years to the development of electronics in the mass market. 'It took 25 years to go from 1200bps to 9600bps. Now it has jumped to 10Mbps in five years.'
In the early days (circa 1980-90) the bandwidth for the diver-installed module used extensively in the UK North Sea and shallow waters globally was 1200bps. There was very little intelligent instrumentation, perhaps a downhole pressure temperature gauge. The Forlock model (circa 1990-95) used predominantly in the Norwegian North Sea for Statoil and Hydro still had a 1200bps bandwidth, but there was an emerging demand for exotic instruments.
The old style Twinlock (circa 1990-2000) was used extensively in shallow waters globally to 600m. The communication was again 1200bps with a data link to a downhole gauge. The new style Twinlock Configurable (circa 2005-onwards) for shallow to deep waters up to 2000m, has a bandwidth of 10Mbps to accommodate greatly increased demand for data links. It can be backwardly compatible with legacy products as well, Robertson notes.
The old style Monolock (circa 1990-2000) was used globally in deep waters to 2700m, its circular shape lending itself to fine alignment in deep water. The communications was 1200bps. For the old style IconSEM Monolock (circa 2000 onwards), used globally in waters up to 2700m deep, the communication speed had moved up to 9600bps and there were up to 12 serial interfaces. The new Style Monolock Configurable (circa 2010 onwards) has a communication speed of 10Mbps. It has been designed 'off-project', with extensive market analysis to define requirements, for shallow to deep waters up to 3000m.
With subsea production control rapidly becoming more complex, and subsea stepouts moving from short distances to tiebacks of up to 150km in just 5-10 years, Robertson points to the greater demands placed on instrumentation by newer applications such as pumping and compressor control or process boosting, and light well intervention. 'In two to three years time we could be looking at data speeds of 1Gbps,' he predicts. 'Electric actuation, condition monitoring and subsea separation are all being developed right now. The module will take that capability very soon.'
In five to 10 years' time he envisages requirements for subsea plant control, bulk separation, gas/oil/water treatment, gas compression, gas/water injection, long distance transport, storage and offloading, power supply and remote operation. 'We'll probably need to develop more complex, different applications, moving out of tree and simple manifold applications. The emerging requirements will dictate the pace and the technology required for the further evolution of the control module.'
Offering some examples of the quickening pace of technology development in this sector, Robertson points out that in 1996 there were five devices attached to a Troll well control module. By 2006 there were 15 on a Reliance subsea well, with three times the amount of instrumentation attached to the one well. 'As a result there has been a huge increase in the capex per subsea well,' he says. More advanced subsea equipment required improved monitoring, but resulted in a reduced risk of downtime or complications, and improved equipment performance. With increased use of subsea processing equipment there was an information need for production optimisation, and integration between sensors and subsea systems.
Digital oilfield developments were also on the subsea agenda during Aker Solutions' Aberdeen technology day. Rohit Singh, Oslo-based VP, new service technologies, prefaced his talk on eField 'real time' initiatives in subsea with the reminder that digital oilfield concepts were far from new, a 2002 multi-client study by Cera subtitled 'enabling next-generation reservoir performance' possibly representing the first comprehensive review of the topic.
'It continues to be a powerful concept to help tackle rising complexity, the experience gap and data overload,' says Singh. 'There is rising complexity in green field developments in harsher environments, deepwater, HP/HT, Arctic etc. For brownfield developments there is a strong push for clients to get more out of their asset, with artificial lift and secondary and tertiary recovery. There is also high competition in open areas with technology as a differentiator.'
Although there are good examples globally of companies seeing real benefits in applying digital technology to very targeted areas such as real time drilling, Singh takes the view that the digital oilfield still remains 'a little bit blue sky'. The challenge for the service industry is to find a place in the digital oilfield puzzle, he observes, adding that he feels Aker Solutions has a particular role to play in asset integrity, or the prevention of downtime, 'because, having designed its products, it understands them at a level of detail which is higher than for the clients'.
Much of today's eField work is asset integrity focused, Singh notes. 'It's about getting as recent data as possible, then acting on it as soon as possible with the right expertise in place and ready to react. It's not going to require a huge technological revolution. It is a merging of technology and competence in the way we work, which is really the key to e-Thinking.'
He highlights a couple of the company's R&D monitoring projects. One is a state-of-the-art subsea pump monitoring system, being run as a dedicated R&D project outwith a client delivery project, the other being Statoil's Ormen Lange Pilot, which, since it is not really subsea, has enabled heavy instrumentation. A 'huge amount of rich and varied data' had been gathered on the Ormen Lange project, he notes, creating 'a golden opportunity to analyse this data in an effective way'. The next step, he adds, would be industrialisation of system design, with enhanced security and multi-site features, and integration with SAP.
Singh's vision for the future is real-time monitoring, rapid troubleshooting and advanced optimisation in a distributed setting. He says his company needs to be able to involve its sub-vendors, because they are often a key part of the delivery with extra insights, as well as its service bases, which are typically the first line of support, and the product centres of excellence for deeper support.
Matt Corbin, Aberdeen-based MD with Aker Solutions, comments: 'Our industry is constantly evolving and the requirement for new design and technology innovations is constant. Customer needs underlies all of our current and potential future products, ensuring our expertise is applied to the areas today, which will take the industry to where it needs to be tomorrow.' OE