A virtual reality tour offshore

Maersk Oil’s Culzean project could provide 5% of the UK’s gas needs, and equipment must be able to handle the high pressures and temperatures. Even virtual reality kits are being used as attention to the smallest detail is required for operations to run smoothly.

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Watch the movie about the technology behind Culzean. 2:44

The Culzean project

  • Approved by the UK Oil and Gas Authority in August 2015, Culzean is located about 240 kilometres off Aberdeen and is expected to produce enough gas to meet 5% of total UK demand at peak production in 2020/21
  • Maersk Oil UK (49.99%) is the operator of the high pressure, high temperature (HPHT) field. JX Nippon (34.01%) and Britoil (BP) (16%) are its partners
  • It benefits from an HPHT fiscal allowance, which exempts a portion of a company’s profits from the supplementary charge, or top-up tax paid by the North Sea industry

Claus Vissing-Jørgensen turns to the left and starts across the bridge, leaving the processing facility for a 150-metre walk above the North Sea waves. He has already taken a tour of Culzean’s well head platform and is about to take the stairs and pass a series of cabins and leisure rooms before reaching the canteen.

Vissing-Jørgensen, Facilities Manager for the Culzean gas project, is not offshore – and the platforms do not even exist yet. Instead, he is in the more comfortable surroundings of Maersk Oil’s Aberdeen office, using a virtual reality tool to troubleshoot potential issues in the hardware that is expected to start producing in 2019.

“It’s an intelligent way of looking at the design through different eyes,” says Vissing-Jørgensen. “It means we can avoid future complications and ensure we are building safety into the design of the project, using best environmental practice and best available technology.”

Extreme conditions

The long distance between three separate platforms – for drilling and production, processing and accommodation – is one of many distinctive characteristics of the Culzean project, which will harness cutting-edge technology to extract gas under temperatures of up to 175o C and pressure that is equivalent to being nine kilometres under water. Maersk Oil’s share of the investment is USD 2.3 billion.

Culzean
The extreme conditions mean materials must have the strength to stand up to the pressure and temperature, and safety considerations are being built into the design.
Culzean field

Maersk Oil’s Culzean project

  • Expected to meet 5% of total UK gas demand at peak production in 2020/21
  • Plateau production of 60,000–90,000 boepd expected
  • Water depth is 88 m, drilling temperatures up to 175 degrees celsius and drilling depth is 4,500 metres
  • Resources estimated at 250–300 million barrels of oil equivalent. Production is expected to start in 2019 and continue for at least 13 years with peak production in 2020/21

The extreme conditions on Culzean mean planning is paramount. Materials must be strong enough to stand up to the pressure and temperature, and safety considerations are therefore being built into the design. The overall idea is to take proven technology and hardware and expand or upgrade it to fit the project.

The “Walkinside” tour that Vissing-Jørgensen is taking with the help of an Xbox controller will allow designers to iron out inefficiencies and potential trouble spots that might not occur to them without being able to visualise the facilities as they will be in reality. That could include something as obvious and straightforward as spotting a valve that is two metres off the ground and lowering it in the final design.

The design mantra

The design is laid out with the highest focus on safety and avoiding risk to personnel, with the accommodation placed as a safe haven some 270 metres away from the wells.

Some parts used in construction of the facilities will be made using hot isostatic pressing of metal dust to create extremely strong materials, which is known as HIP Process. Highly rated hub connectors will be applied where welding is impractical.

“Keeping it simple really is a design mantra on Culzean,” says Martin Urquhart, the Project Manager. “The pressure and temperature are the complicating factors, so materials have to be much stronger to cope with both extremes. We like to use simple tried and tested methods and make decisions that build in extra safety margins wherever we can.”

Penetrating the surface

Maersk Oil has commissioned a new drilling rig for Culzean, based on an established design with specific, hi-spec additions to deal with the particular conditions, says Andrew Lough, the Wells Manager for Culzean. One of the big challenges is getting a rig cantilever – the movable structure that can allow drilling of multiple wells from a single location – which can move around easily and access all the wells that need to be drilled from one position.

Maersk Oil

Top five ambitions

  • There is still considerable potential remaining in the North Sea but it requires the right expertise and technology, such as that Maersk Oil is employing on Culzean, to extract it. The business aims to become one of the five biggest producers in the North Sea in the first half of the next decade.
  • It can achieve this through a combination of its existing portfolio, major capital investment in projects like Culzean and Johan Sverdrup – one of Norway’s largest ever discoveries – and more efficient operations.

Designed to operate in water depths of up to 120m and drill to more than 4,500m, the drilling rig will be bigger than the present standard and in order to get as close to the platform as possible, the jacket of the wellhead platform has a twisted base such that the rig’s legs sit either side. This is just one of many design considerations integrated in the “front end loading” phase of the project.

“We’ve taken existing elements from other rigs that worked really well and brought them into an older design that is proven and effective, and really brought it up to date,” Lough says.

During the important testing of materials, in one instance the team found that standard industry tubing for the wells could not stand up to the high pressures. They had to look at new, proprietary treatment for the steel, which would give it the necessary strength while keeping the right thickness to operate and contain the pressure from the wells at great depths.

“Culzean is a huge project that needs comprehensive planning to gain the rewards,” says Urquhart. “Our planning is coming down to the tiny little details – they may look unimportant now, but could end up as the crux of the matter and on the critical path.”