Umbilicals: reducing the risk

David Morgan
Thursday, March 1, 2012

Representing a $2 million capital investment so far, the test, qualification & reliability (TQR) laboratory at Oceaneering Umbilical Solutions' Rosyth plant in Scotland boasts an unrivalled collection of cutting-edge umbilical testing and analysis equipment. And there is more to come as the company pursues its linked goals of building a better knowledge base and developing the ultimate product reliability package.

Research & development has long been in the company's DNA but a few years back Oceaneering Umbilical Solutions (OUS) experienced something of an epiphany. ‘We realised that our knowledge base, though always quite strong, would only get us to a certain point,' explains Rosyth general manager Mike Smith. ‘We made a decision then to really start driving the market forward from a technological standpoint by developing our own technologies, testing our theories, going beyond the published calculations we give our clients and telling them what they mean in real terms, looking for better ways to design our processes and produce a better product. That's really the genesis of the TQR lab.'

Focusing more on the scientific side of the business was driven very much by customer need, adds Smith. ‘You are who your clients think you are,' he offers. ‘Companies can spend billions of dollars trying to define who they are, but irrespective of what you try to do, how many consultants you hire and how much information you dig up, you are to your clients who your clients believe you are. So our response over the past several years has been to take the opportunity to go build up a basis of knowledge and a basis of talent to be able to give the market the things that they require of us.'

The establishment of a central engineering group, in which the new TQR facility plays a key role, helped set the ball rolling. Today this group, under global engineering manager Greg Scott, coordinates the engineering efforts of the three OUS regional manufacturing locations: Rosyth, Niteroi in Brazil and Panama City in Florida. Plans are advancing for a dedicated TQR facility for the huge Brazilian offshore market, the Oceaneering board having just approved additional capital expenditures on the Niteroi plant following completion of an initial multi-million dollar expansion programme there.

The reliability question

Reliability is uppermost in the minds of offshore operators these days, especially those who have paid the heavy price of subsea kit failures in the past. It's very much the buzz word among oil company visitors to Rosyth, says Smith, and pretty well dominates the OUS presentation materials. ‘In a half-a-billion dollar field development our product will probably be a $50-70 million piece, not that big in relative terms. But guess what? None of the rest of that field development works without this product. If it fails, the whole operation goes down.

‘There are warranties of course, but they are essentially meaningless when an umbilical out in the field controlling 100,000b/d goes down. When that flow stops things get excited very quickly!

‘Fortunately we've never had a major failure that was actually caused by an umbilical fault,' he adds, although there are of course situations – anchor drag, storm damage and the like – that are beyond the manufacturer's ability to control. For Gryphon field operator Maersk Oil, for example, the Rosyth factory is replacing some umbilicals damaged when the FPSO lost station last year during a North Sea storm.

While Smith stresses that OUS has always put a premium on reliability from a product design standpoint, the approach today goes beyond questions of robustness – thicker walled tubes, heavier armouring, and so forth – and focuses on finding better, science-based ways to drive reliability. ‘That's the sort of thing our central engineering group is chasing for now, so that we can de-risk the project for the client,' notes Smith. ‘One of our biggest value propositions to our clients in the market today is eliminating the risk.'

Greg Scott chips in: ‘It's really the engineering science behind reliability that we need to demonstrate that we understand. With most umbilical suppliers, the approach to reliability has been: "Well, what are the specs that you want us to meet and we'll just test to that." Then they'll do a lot of empirical testing, and if it doesn't break, it's reliable. But how can they know how reliable it is if they haven't done any of the engineering science behind it.'

OUS products typically are expected to last 25-30 years in the field, but with client feedback on in-service performance highly unlikely once the product is wet the company sees a combination of data-driven predictability analysis and physical testing as the only surefire way of backing up its calculations. That's where the TQR lab comes in. ‘It's a correlation between the two: the demonstrated test data through the facilities we've got and the engineering that we've plugged in there, and the predictive reliability figures that calculate plus the predictive analysis data,' notes Scott. ‘When you tie all those things together you've got the very powerful basis of design that customers are looking for these days.'

Having access to an established in-house resource that has operated for years in the vanguard of reliability engineering will do the OUS cause no harm. Oceaneering's Space Systems Division in Houston can lay claim to having developed work procedures and some of the suits, manipulator arms and other tools employed in manned space flight. The rationale behind this business outgrowth might have puzzled some observers at the time, but it made infinite sense to Smith. ‘There's so much commonality between working in depth and working in space; it's so similar to what we do 300ft down in suits.'

And with the recent cessation of the US space shuttle programme, Scott sees an opportunity to leverage some of that expertise. ‘They are very mature in the way they design for reliability,' he says. ‘So we're hooking up our engineers with their engineers to get that transfer of knowledge at a shared level.

‘We're seeing a lot of demand in the market now for high quality power – medium and low voltage for control – as the industry goes into deeper fields, with a lot more assisted lift, compression and subsea processing, and that brings with it different mechanical and electrical engineering challenges.'

Third-party testing at Rosyth may also be on the cards some day, the plant having recently been approached by a competitor at the behest of one of its clients. But the majority of the TQR lab's work will be for internal clients and for R&D and knowledge creation, confirms Scott.

With an eye to correlating its results with those of other research teams and adjusting some of its manufacturing parameters accordingly, OUS is also very active externally in a number of joint industry projects. The Rosyth facility, for example, built a test umbilical for a Norwegian-led JIP on U-Flex, a local analysis tool for determining crush and various other factors on an umbilical cross-section (OE September 2011). The JIP, facilitated by Marintek at its Trondheim laboratory, is now in its second stage.

OUS has long-standing links with Heriot-Watt University in nearby Edinburgh, whose thermal and pressure test facilities contributed much to the company's work on gas and water migration for thermo-electrical cables in pre-TQR lab days. The thriving subsea engineering programmes at Heriot-Watt and, further north, Aberdeen University also provide a source of recruits for the undergraduate vocational programme Rosyth started last summer as the plant stepped up its efforts, in Scott's words, to ‘keep the talent funnel fed' with graduate trainees.

Consultancy role

‘Analysis is a big area for us, it's what builds confidence,' declares Scott. A few years back OUS outsourced much of that work, ‘so not only were we losing a business opportunity but we were losing the opportunity to gain first-hand knowledge about how our systems work and how our design rules should be tailored to those predictions', he says. ‘Now we are virtually independent and have 12 analysts globally doing some pretty advanced work on all sorts of systems – static, dynamic, electrical, thermal – so we have that consultancy basis and have a number of PhD people working in that space as well. It's basically an engineering consultancy offer that we provide to our clients, and it does bring a lot of value into the company.

‘And we're positioning the test service as a consultancy service as well,' he adds. ‘Employing high-value services to build confidence in the solutions that we're going to manufacture is very important to us, but so is supporting clients in FEED studies so that we can help influence the design direction to their solution. We want to know what the oil companies want from us, but we also want them to know what we can do for them. So it's very much a push-pull relationship there,' concludes Scott.

Oil companies are not the only people in the OUS crosshairs, however. Mike Smith explains: ‘The umbilical sees more stress at the point of installation than it will most likely see in its entire life. It's the most concentrated stress on the umbilical, with all of the components moving around inside of it and stick-slip behaviour etc, as it bends over to go off the back deck of the vessel or into the moonpool. ‘A lot of our test lab work is around installability, so you understand the limit of crush on the umbilical, the friction level, the tensile strength. With all of those parameters, it's very important for us to stay close to the installer to understand what forces and stresses they are going to put on our umbilical.'

A particularly challenging recent order was the 66km umbilical – the longest manufactured at Rosyth to date – due for loadout in March into the plant's deepwater channel and destined for deployment by installation contractor McDermott on BHP Billiton's Macedon project, a subsea well tieback to an onshore control facility in Western Australia. ‘We had to open the complete engineering book on that one,' declares Smith, since that the umbilical will go from subsea, on the beach, over sand dunes, through a swamp, under a river, through another swamp and then onto dry land before finally entering the processing plant.

‘So every possible stress and strain you can have on a product will be there,' he adds, ‘and with the warm water we had to deal with thermal issues too'. There was also the threat of teredo infestation. Otherwise known as shipworms, and with drill bits for teeth, boring teredos have preyed on ships' timbers for hundreds of years and in more recent times have shown a particular liking for oil industry umbilicals and conductor insulation. They are allergic however to copper compounds. So the various site-specific novelties built into the Macedon umbilical by the Rosyth team includes an internal strip of brass tape guaranteed to stop any invading molluscs in their tracks.  DM

Rosyth facilitiesIn common with the other OUS manufacturing facilities, Rosyth produces the full range of pump, thermoplastic hose, hybrid, electric, power, fibre optic and steel tube umbilicals.

The Rosyth TQR lab includes a full-scale fatigue test machine; a tensile test machine with crush mode; a tensile-with-bend test machine; free-flooding rate verification test equipment, and an impact test machine. Its analysis capability, also compliant with ISO 13628-5:2009 (API Spec 17E-2011), boasts non-linear and multi-physics FEA solvers for advanced simulation work, for example coupled EMI/thermal analysis to eliminate cross-talk and establish power cable temperatures, or frequency response analysis for calculating critical load conditions for slender structures.

Under the microscope when OE visited the test lab was armour wire destined eventually for use on Petrobras' ultra-deepwater Guara field in the presalt offshore Brazil. ‘This is a high-performing armour wire because of the depth of application,' explains Rosyth's test centre manager Dr Alan McGurk. ‘So we're just verifying the tensile strength and trying to produce S/N curves for the wire (a) to verify "yes, we need that wire for that application" and (b) to capture that performance data as knowledge for ourselves.'

On the cards as part of future expansion of the TQR lab, reports McGurk, is a system for Arctic environment umbilical design simulation while, on the intervention side, ‘we're looking to get more involved in IWOC [Installation and Workover Control System) umbilicals testing, for example the critical reeling/unreeling processes'. 

Categories: Equipment Subsea Europe

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