Design frees up jackup deck space
  from: Offshore Engineer
  by: Jennifer Pallanich
  Wednesday, March 19, 2008

Four new identical jackups under construction in Southeast Asia could be the most efficient rigs in their class to-date. OE’s Jennifer Pallanich talks to the contractors about how they believe the design will reduce drilling costs and about their outlook on the drilling market in the years to come.

More open deck space, automation and an XY cantilever on the four jackups that Keppel-Fels’ Singapore yard is building for Maersk Contractors are expected to translate into higher levels of safety and 20% efficiency improvement over conventional units.

‘We expect these rigs will outperform anything in the 350ft market,’ says Claus Hemmingsen, Maersk Contractors’ CEO.

Designed by GustoMSC and engineers at Maersk Contractors, the design frees up more room for storage, facilitating logistics, and also automated tasks where possible on the drill floor and throughout the rig, such as with mud mixing.

‘We’ve taken the man-handling out of the equation,’ says Maersk Contractors’ project director Morten Norderud- Poulsen.

Maersk says the unit has double the open deck space of conventional rigs and many wide paths throughout the unit mean workers can move heavy loads from one place to another via forklifts, rather than cranes. Lars Kasueske, the senior drilling superintendent for Maersk Contractors, estimates the new design will halve the number of crane operations carried out onboard as compared to conventional jackups.

‘We see crane operations as one of the main contributors to accidents on rigs,’ he says.

Raising the XY cantilever 3m above the main deck is one factor that makes the open space on the main deck possible. The company says this frees up space for storage under the XY cantilever. The longer structure of the XY cantilever, the company says, accommodates two pipe racks end to end on top, rather than the traditional one, which allows arriving tubulars to be placed on the cantilever deck rather than stored on the main deck. The mud treatment area is built into the cantilever structure as well.

Maersk first used the XY cantilever on its Maersk Innovator, constructed in 2003. The cantilever can skid transversely (in the X direction) as well as longitudinally (in the Y direction) as one fixed unit. Norderud-Poulsen says the raised XY cantilever design allows one-third more transverse skidding.

With the XY cantilever, the well center is fixed relative to the cantilever, which means the BOP needs only two positions, well center and parking/test position, according to the company. There is no need to change the BOP during drilling, Kasueske says.

The unit’s design moves the deck cranes from the main deck to the jacking structure. Additionally, the design moves the drawworks from the rig floor to the elevated deck outside the derrick and routes the exhaust vent shafts under the deckspace to behind the jacking houses. The design removes the accommodation block from the main deck and wraps it around the forward leg.

Another improvement in efficiency comes from the vertical storage and makeup of longer segments of tubulars in the 75m high derrick, the company says. The high-efficiency design makes room for storing up to 135ft of tubulars, rather than the traditional designs that accommodate 90ft of tubulars, Norderud- Poulsen says. The jackup’s drill floor features two vertical foxholes where stands of three joints of casing can be made up without using the rotary table, according to Kasueske. The racking of three-joint stands of casing in the derrick is also possible. These design elements account for a one-third reduction in the amount of time it takes to make up the tubulars, Norderud-Poulsen says, which translates into speedier insertion of casing into the hole to reduce cost and the risk of well collapse. Both pipe handling on the drill floor and pipe transfer from the cantilever pipe racks to the drill floor are fully mechanized on the rig, according to the company. T

he new TorqueMaster machine, capable of making up both drillpipe and casing, is on the rigfloor. It combines the strong points of automated iron roughnecks and other casing roughneck machines into one unit able to make up all types of tubulars, including drillpipe, drill collars, casing, tubing, and liners without requiring third-party equipment, according to Maersk.

The jackup can hold 6000bbl of liquid mud and can accommodate up to three mud systems at once, allowing quick shifts between types of mud, Kasueske says. The mixing of the mud is automated.

Kasueske says certain areas of the rig will also be quieter than on conventional rigs because ‘most of our equipment is water cooled instead of air cooled.’

Norderud-Poulsen says five main changes to conventional jackup design are expected to create the efficiencies for Maersk’s new jackup units: increased level of automation and mechanization, the XY cantilever, the 75m high derrick, the open deck space, and the optimized layout.

The design combines and adopts proven features from the company’s harshenvironment jackups.

‘This efficiency has not yet been recognized yet by the industry’ because it hasn’t yet worked offshore, says Paul Carsten Pedersen, Maersk Contractors’ group senior vice president and chief commercial officer. He says the company has seen similar or better efficiency gains from the older sister rig, the Maersk Innovator, in the North Sea. The firm expects to prove the efficiency of the design while the first completed unit works in the Persian Gulf under a threeyear contract.

Norderud-Poulsen says the efficiency improvements should allow Maersk Contractors to drill seven wells in the time it takes a conventional jackup to drill five, all else being equal.

The efficiencies were not gained to the detriment of weight, Kasueske says, adding the jackup has more combined drilling load than other jackups.

The first jackup, the Maersk Resilient, is under a three-year contract to Dubai Petroleum and slated to begin work in early 2Q 2008. Fabrication of the second jackup, unnamed as of press time, was about 90% complete as of the end of January, and that unit is under a threeyear contract to DONG in Denmark. Fabrication of the third jackup was about 60% complete as of the end of January, and no contract has been signed yet for this unit. Fabrication of the final of the four jackups was about 10% complete as of the end of January, and it is also without a contract as yet.

Eyes on Vincent

Maersk also has Keppel’s Singapore yard busy finishing up the conversion of the Ellen Maersk Suezmax tanker into the Vincent FPSO for Woodside’s field offshore Western Australia. The converted FPSO will have facilities to store 1.2 million barrels of oil and produce 120,000b/d. It can handle 250,000b/d of liquids, export 100mmcf/d of gas, and inject 230,000b/d of water. Woodside has access to the FPSO under a 2008-2015 contract with options. It is expected to be onsite in spring 2008.

The Ellen Maersk, an E-class double hull VLCC originally built in 2000 by Hyundai, is 335m long, 58m wide and 31m high with 308,000dwt. The converted FPSO will work in 350m of water depth and support 13 risers, receiving 17.5°API oil.

The FPSO is designed to avoid continuously flaring. Because the field is in a cyclone-prone area, the FPSO features a disconnectable mooring in a turret system.

‘We can prepare ourselves for a disconnect very fast,’ says Christian Eilersen, project director.

Pedersen says that this conversion job is costing on the lower end of the publicly stated $700 million to $1 billion the company is laying out for advanced VLCC-based FPSOs.

Rosy outlook

‘Our fleet is designed to cover all the main areas, and we’re about to be present in all the main areas,’ Hemmingsen says.

The company has rigs working in the North Sea, the Middle East, off Southeast Asia, off Australia, off West Africa, the Caspian Sea and off Venezuela. Soon, the company will add rigs to areas in the Gulf of Mexico and off Brazil.

‘The rig fleet in the world is not exactly young anymore,’ Hemmingsen says, citing a figure indicating the average age of rigs is about 25 years old. The oldest rigs, then, are on the way to being worn out or otherwise substandard if not heavily upgraded – or are already there, he adds. Despite this, he expects some delay in the retirement of older vessels. ‘As long as the market is good, the equipment will keep working.’

Hemmingsen says the company sees a good outlook for the industry in the next five years. For every FPSO conversion that Maersk Contractors brings into the market, he says, the company invests between $700 million and $1 billion. He declined to state how much the company spends on newbuild jackups, but he did say the company has committed to investing over $3 billion in rigs and FPSOs between 2007 and 2010.

‘From a supply and demand side, this is the reason you’re seeing a boom in rig building right now,’ Hemmingsen says, calling the picture of the way forward comforting. ‘That’s why we’re investing without much concern. Maybe that’s the wrong way to put it.We’re always concerned. But we’re confident.’

On the flip side, staffing is still difficult, he says, and part of the reason for that is the industry’s poor image. He calls on the oil and gas world to tackle the industry’s image problem and indicates his own company is striving to improve the industry’s public perception.

‘If we don’t manage this task, it means our competitors won’t manage this task, and our industry won’t manage this task, and then we’ll have a problem with energy supply in the future,’ Hemmingsen says. OE

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