Mariner, Aasta Hansteen projects set back

Statoil’s US$7 billion Mariner heavy oil project in the UK North Sea has been set back a year due to engineering and construction delays, the operator revealed today. 

The Norwegian operator's Aasta Hansteen project, in the Norwegian Sea, has also suffered a one-year delay with costs set to increase 9%. The spar hull for Aasta Hansteen, Norway's first spar development, is being built at Hyundai Heavy Industries' yard in South Korea under a consortium deal with Technip. HHI also has a contract for topsides on the project. 

For Mariner, costs on the development, comprising a 38,000-tonne topside on the largest jacket Statoil has ever built, will increase 10%, revealed Managing Director for Statoil Production UK Tove Stuhr Sjøblom at a briefing in Aberdeen this morning.

However, thanks to new seismic and subsurface work on the two reservoirs which comprise Mariner, the project’s reserves have been increased by 15%, said Vice President Chris Andrews. 

Sjøblom said: “We have a challenge with construction at Daewoo Shipbuilding & Marine Engineering. Sailaway has been delayed from 2016 to 2017. This delay will lead to a delay in the startup of production from 2017 to 2018. As part of this, there will be a cost increase of 10%.

“That delay will impact what we do in 2016. We are in dialogue with suppliers to discuss solutions. We don’t need to change the scope, it is more about timing. 2016-17 will be used for pre-drilling, which will give us more wells ready for production at startup.

“The good news is that we acquired seismic in 2012, which is much better quality and that has reduced the reservoir uncertainty and indicated some upside, we are quite excited about. We will use the extra time we have to mature these opportunities.”

Explaining what the issues at DSME were, VP Ingolf Søreide, said: “Detailed engineering was delayed and procurement. This resulted in late startup of construction of the modules themselves. Then DSME have had capacity problems, during last year, so there were real effects from earlier projects being delayed, so construction was delayed for that reason. We also see a stretch on resources their resources when it comes to welders, yard space and so on. It has been a hot market since 2012, and even though the oil prices has gone down they are still trying to deliver on projects.“

VP Chris Andrews said: “It is a huge topside, around about 38,000-tonne, which is large by any standard, with five modules up to 10,000-tonne each. The platform modules, once complete, will now be transported, by heavy transport vessels, to the North Sea from South Korea during 2017. 

Progress has been being achieved at the site in the North Sea, in Block 9/11, 150km east of the Shetland Islands. Andrews said: “This year we installed most of the infield infrastructure, including riser bases.> Next year, about 4-6 wells will be pre-drilled from next summer following the arrival of the Cat J jackup. “The idea is to get a robust well stock in place before we start production, which will allow ramp up quicker than planned, give us a much more robust production profile in the early years and sustain the production plateau,” he says.

Andrews said the firm had had good results from the seismic shot in 2012. While the Maureen reservoir on Mariner was better understood, the seismic data has helped refine the drainage strategy, says Andrews, helping increase the reserves by 15%, compared to what Statoil had seen at project sanction.

The data has also helped image the harder to see Heimdal reservoir, enabling Statoil to better target sand bodies, in turn allowing the firm to reduce the number of wells it will need to drill and both increase and accelerate production. 

“This is ongoing work, but we intend to have a new drainage strategy in place in Q1 next year,” Andrews says. 

The project’s jacket, fabricated at Dragados’ yard in Cadiz, Spain, was installed earlier this year, alongside a campaign to install most of the subsea infrastructure. A Cat J jackup rig is being built in Singapore and is due to arrive in summer next year to start pre-drilling with the platform topsides due to arrive during 2017. A floating storage unit for the field is due to be completed in Q1 2016 at Samsung heavy industries.

On Aasta Hansteen, the Polarled Pipeline, which connects the field 482km back to shore, has been completed. 

Read more 

Constructing mariner 

Factory drilling

Images from Statoil

Top - work on the utilities module underway with the three decks constructed.

Second - the eight storey-high living quarters module

Third - artists impression showing pre-drilling

Bottom - the Mariner field over view.

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