Oil platforms are massive constructions which help us to tap into oil reservoirs deep below the seabed. One such platform is Edvard Grieg, which was successfully erected this year on the west coast of Norway. It has been producing oil from the North Sea since the end of 2015, yet to get to this stage required four major work stages and countless minor steps. But how precisely do you build a platform like this so that it all comes together in the end?
Thousands of tonnes were placed with millimeter-accuracy right before my very eyes – an incredible achievement.
There’s not much that can make an impression on those like Morten Krogh who have been involved with offshore installations every day for years. But 3 July 2015 was a special day even for the experienced Asset Development Manager: 10,500 tonnes, that’s how much the module weighed which had to be hoisted onto the steel jacket of the Edvard Grieg platform by the semi-submersible crane vessel “Thialf ”. A weight that only two ships in the whole world can handle. The procedure took three hours and was then followed by four months of hook-up and completion work to prepare the Edvard Grieg oil platform for its purpose. These were the final steps in a project which had seen more than 42 months of hard work.
The first step: Searching for cooperation partners
“It all starts with the decision to build a new platform. In general, there is an operator – this is Lundin Norway AS on the Edvard Grieg project – who makes the key decisions in agreement with the other project partners and bears the main responsibility for the project development,” explains Morten Krogh. It’s easy to see why multiple companies are involved in a project of this kind: Building oil rigs is a complex and cost-intensive business, that’s why oil and gas companies cooperate with other companies from the industry who contribute their expertise and experience.
We have a certain tradition in Norway of building oil platforms in close cooperation with the contractors and the partner companies.
The design of the platform
OMV entered the Edvard Grieg project in 2012. At this point the so-called “Engineering and Procurement Phase” had already been completed. In these first months, the planning of the oil platform happens – from the size of the helicopter deck right down to the power socket on the wall. “Things that sound trivial can turn out to be decisive,” says Morten Krogh. After all, even the tiniest flaw in the design can lead to delays later on, costing many millions of Euros. To ensure this doesn’t happen, computer simulation is used to check that everything has been thought through. Hundreds of engineers in India and Norway spent almost a year and a half perfecting the design of Edvard Grieg.
And this precise preparatory work has really paid off, says Morten Krogh: “In the early phases of construction, Lundin made good decisions and heavily involved other partners with their experience in the planning phase. Lundin’s open culture of communication with partners also made it possible for us to take on a proactive role in the Edvard Grieg project.”
The construction phase begins
The actual construction of the platform – the so-called Fabrication Phase – is a mega project all by itself: Edvard Grieg was built in a total of five different yards in Poland and Norway. There are multiple reasons for this according to Morten Krogh: Just like in a house, where every room has a different function, a platform also consists of parts which each fulfill a different role:
The dimensions of the individual parts are enormous – the flare tower alone weighs 252 tonnes, while the steel jacket comes in at a massive 13,000 tonnes. And because this would exceed the capacities of any individual yard, the separate components are built at different locations. The second reason, says Morten Krogh, is that tenders are only awarded to those who are capable of doing the best and most efficient job.
Piece by piece – the individual components come together
After a construction period of more than two years, the critical phase of an oil platform like Edvard Grieg slowly starts: Namely, the so-called Assembly Phase when one can finally see whether all the effort at the beginning has paid off. This is when the individual components are shipped, collected, and fitted together step by step. Over a period lasting several weeks, more than 600 people ensure that every cable, every pipe, and every wall is just as it should be, explains Morten Krogh: “The individual modules of an oil platform are completed on land as far as possible.”
But with a total weight of approximately 22,500 tonnes for the Topside Modules, even a crane vessel like the Thialf reaches its limit. This is why the platform is not completely finished on land, but on the high seas. The individual parts are loaded onto cargo barges and taken out to sea where the steel foundation has already been set in place a year ago. One by one the individual modules are lifted on to the base and fixed in place with the help of the huge cranes.
Put to the test
And if everything goes to plan, as it did on July 3, 2015, then parts of the system can start being handed over to the crew following yet another check. And that, says Anders Henriksson, can take several weeks: “We test the systems and the equipment which we will use on the platform very thoroughly. It is only then that the operating crew starts working on the platform.”
But even though the so-called “heavy lift” with the Thialf and all of the time-consuming hook-up work on the high seas looks spectacular, it is not what makes building an oil platform such a challenge. After all, says Morten Krogh, the secret behind an oil platform is what hundreds of colleagues have achieved in the preceding months in terms of planning, organization, and painstaking technical work – namely made-to-measure engineering.
First oil from Edvard Grieg
Finally, on November 28, 2015, oil production at the Edvard Grieg field started. Watch some of the most exciting moments and most important milestones of this project in the following video:
- The Edvard Grieg consortium: Lundin Norway AS (operator, 50%), OMV (Norge) AS (20%), Wintershall Norge (15%), Statoil (15%).
- The Edvard Grieg field was discovered in 2007. It lies around 180 km west of Stavanger in the North Sea.
- The platform measures 202 meters from the anchorage in the seabed to its highest point, as a whole it weighs much more than 30,000 tonnes, making it more than three times as heavy as the Eiffel Tower.
- Based on planning, the platform should produce around 100,000 barrels of oil a day at peak from more than 15 wells.