Designs on the future

June 4, 2014

Copenhagen's Ramboll Group pocketed two intricate Statoil pipeline contracts and announced a new office in Houston. Sarah Parker Musarra discussed the company's latest developments with Project Manager Jan Bohl Andersen.

Two major Statoil projects are scheduled to come online in 2017. Engineering, design, and management consultancy group Ramboll are behind subsea pipeline design for both of them. The Copenhagen-based company is responsible for the design and engineering of the Polarled subsea pipeline, connecting the Aasta Hansteen platform with the Nyhamna terminal, and the pipelines of the Gina Krog field development. The Polarled pipeline will be finalized 4Q 2016.

The large Polarled pipeline will cross the Polar Circle, and will be laid in record water depth for its 36in. size, with an inner diameter of 34in., exporting gas from the Aasta Hansteen development in the Norwegian Sea to the Nyhamna gas plant. With the capacity for future developments to be tied in, it stands to make a major impact on Norwegian Sea production.

“The Norwegian Sea is an exciting area on the Norwegian continental shelf. Polarled underpins this. Establishing new infrastructure increases the opportunities for the discoveries already made, and at the same time paves the way for further exploration and the development of future discoveries,” said Rune Bjørnson, Statoil’s senior vice president of Natural Gas, in 2013.

The Norwegian giant labeled Gina Krog as “among [its] major new develop- ments.” While it might seem unbelievable that its pipeline design and install phases could be considered as challenging as the complicated, record-breaking Polarled pipeline, Ramboll’s Gina Krog Project Manager Jan Bohl Andersen insists that it is so.

It will be engineered with great care,” Andersen said, chuckling at the overwhelming nature of his understatement.

Gina Krog

Originally known as Dagny field, the now- NOK26 billion (US$4.3 billion) Gina Krog project was originally considered a minor gas development after the discovery of its 15/5-1 well in 1974.

Located around 230km southwest off Stavanger in the Norwegian North Sea, Gina Krog lays in 120m of water, 30km away from the Sleipner field. Gina Krog spans Blocks 15/5 and 15/6 within production licenses (PL) 303, PL 048, PL 029 and PL 029B.

Rendering of the US$4.3 billion Gina Krog development. Ramboll is engineering the pipelines. Images from Ramboll. 

Operator Statoil said that since discovery, the field was brought up for development consideration a number of times. Concepts were tabled each time until 2007, when oil and gas was proven in the neighboring development of Gina Krog Øst (originally Dagny East).

A 100m-long oil column was proven throughout the entire Gina Krog/ Gina Krog Øst structure through appraisal well drilling in 2008 and 2011. Project partner Total said the field, “contributes to the renaissance of hydrocarbon production in the Norwegian North Sea.” Statoil estimated reserves of 225MMboe, giving 600,000bo/d and 9 million cu m/d gas.

Ramboll received the Gina Krog pipeline contract and five subproject contracts in March 2013, just months after being awarded January 2013’s Polarled contract.

Gina Krog’s export pipelines design is currently in follow-on phase, and seabed preparation activities offshore are imminent. Pipeline installation is scheduled in 2015. Marine work, including tie-ins, will take place in 2016.

First oil is scheduled for 2017, but Andersen said the first true test comes well before then.

“The pipeline installation is actually the first part, before the Gina Krog jacket itself come in,” he said.

Heerema is constructing Gina Krog’s 142m-tall jacket. It is the biggest the company has ever produced, and is scheduled to sail in April 2015.


Gina Krog will be tied to Sleipner, allowing the two developments to enjoy a mutually beneficial relationship.

“The Gina Krog field development is one of several fields being developed in the vicinity of the Sleipner hub. This will assist in substituting some of the oil and gas from mature fields with declining production,” Andersen said. Through its tie-back to Sleipner, a concrete gravity platform from the 1990s, Statoil plans for Gina Krog to use the older development’s existing infrastructure.

However, accessing and processing such reserves usually requires many hours of dedicated, creative engineering work. Gina Krog is no exception.

Rendering if the Gina Krog development. Image from Statoil. 

Andersen explained that Gina Krog’s platform, supplied by DSME and engineered by Aker Solutions, will produce oil and gas. Gas will be exported to the Sleipner A platform through a 27km, 20in. export pipeline. A couple of hundred meters from Sleipner, a riser base splits the 20in. pipeline in two 10in. riser extension sections. The two 10in. risers will be pulled-in through existing J-tubes through to topside. Oil will be exported from Gina Krog through a 10in. insulated pipeline, terminating at a permanently- moored FSO tanker. A flexible riser connects the pipeline to the FSO.

“Gina Krog requires gas for gas injection in wells [to maintain reservoir pressure]. This gas will be tapped through a hot tap connection to existing gas pipeline Zeepipe IIA. Zeepipe IIA is owned by Gassco and is part of the Gassled pipeline infrastructure exporting gas to Europe,” Andersen said.

Beyond the delicate riser pull-in, Andersen has identified hot-tapping as another massively complicated operation.

Andersen said that the highly-competent Statoil, which has had a 10-year working relationship with Ramboll, is a very collaborative client, calling it a very open process.


Crossing the Polar Circle, the 36in.- diameter Polarled pipeline runs 482km in water depths reaching nearly 1300m. It will be constructed to transport gas volumes for planned and future developments, including Aasta Hansteen, the world’s tallest spar platform. The pipe- line installation will be in 2015.

At least three Ramboll offices collaborated on the massive project: Denmark, Norway, and India, where much of the drafting work took place.

The wall thickness is between 29-37mm – “very heavy indeed to start with,” he said. Due to the 1300m water depth, which will amount to around 130bar of external pressure, the pipe will have buckle arrestors, i.e. reinforced wall thickness sections, with wall thick- ness of 73.9mm every kilometer or so. The design pressure of the pipeline is 233barG.

Another issue the project will need to contend with is that it runs parallel to other pipelines as it nears the shoreline. Part of the pipeline’s route also runs in the ship traffic lane.

“Due to the harsh environment of the Norwegian Sea, all water depths will be an issue. The more shallow the water the more wave action on seabed,” Andersen said. The parts of Polarled resting in water depth less than 700m will be concrete-coated to ensure stability and protection against trawling.

Another issue is the sea floor itself.

“We have severe challenges in terms of uneven and soft clay seabed. Because of this seabed, there is a lot of seabed prep work for rectifying pipeline free spans, and that is mobilizing just now,” Andersen said. “Due to the uneven seabed, Polarled will shave off around 40 peaks and fill in 200,000cu. m of crushed rock to secure a safe pipeline foundation.

After pipelay, a further 270,000cu. m of rock is the current estimate to rectify the free spans and secure the pipeline.”

First gas for the Aasta Hansteen development is also expected in 2017.

“The Polarled pipeline is the backbone for future field developments offshore central Norway and shall feed gas to the Nyhamna terminal for many years to come,” Andersen explained. “This will assist in continuing high amounts of gas exported to Europe.”

Houston office opening

Already present in 22 countries, Ramboll Group expanded its global footprint last year by partnering its Ramboll Oil & Gas business unit with the 20-year-old, Houston-based Excel Engineering.

“Becoming part of a 10,000 people strong organization such as the Ramboll Group is exciting and obviously provides us with a much larger pool of resources to draw on. When Ramboll approached us and we saw the shared

values and technical match of our companies, it was an easy decision to join the Scandinavian-founded company,” Mostafa Jamal, Excel Engineering Inc. president and CEO, said at the time of the announcement.

Both companies are highly-recognized in their respective areas. Ramboll Group said it is Europe’s fourth-largest consultancy group. The Houston Business Journal recognized Excel Engineering as one of Houston’s top 25 local energy engineering firms.

“Excel Engineering has operated in other markets and deeper water than we have so far. They have also cooperated with a host of contractors and possess immense knowledge about structural engineering in the Gulf of Mexico and a great many [other] locations around the world,” John Sørensen, managing director, Ramboll Oil & Gas, said.

John Sørensen and Mostafa Jamal, president and CEO, Excel Engineering, signed the agreement in Houston 1 Oct 2013. Excel Engineering’s existing office space, located at 3200 Wilcrest Drive, will continue to serve as its office location.

Ramboll looks to add its traditional engineering services plus some of its other specialties, environmental studies and strategic and commercial consultancy to Excel Engineering’s existing client base.

“Houston has been dubbed the oil and gas capital of the world, and if we as a company want to play with the big boys and land the big projects, we need to be active here,” Sørensen concluded.