Subsea Rock Installation
Koos van Oord
‘Our flexible fallpipe vessels had never worked at a depth of almost 1,300 metres before and required refitting for this project. Together with the Ship Management Department we talked about which technical solutions would work at this depth and about the risks. By communicating closely, dividing up the tasks clearly, and making solid plans, the project team and the stakeholders came up with the best possible solution together. I can proudly say that it this worked out great for phase 1. An example of our Marine ingenuity.’
‘Statoil contracted Ramboll for the design of the Polarled pipeline project, the largest and most challenging pipeline project for which we at Ramboll Oil & Gas have been responsible. Due to the scope of the project, there are enormous possibilities to optimise the various technical solutions. In particular, we have developed finite element models for assessing very complicated 3D design challenges. The models provide us with an exceptional understanding of the true physical behaviour of the pipeline and enable us to optimise the pipeline design. I strongly believe Polarled will become a new world-class reference project for us.’
‘New developments compensate for declining production on older fields. Since 2010, Statoil’s annual investments on the Norwegian continental shelf have increased by 75%. The Aasta Hansteen field is one of the fields under development. The 480-kilometre Polarled pipeline project will be step one in developing this new gas region. It’s a large-scale project in which we only want to work with reliable contractors.
Van Oord did a great job in the 2014 pre-lay campaign, I am confident and we are looking forward to a successful post-lay rock installation campaign again in 2015.’
Commentary by stakeholders
Rock is being installed for the Aasta Hansteen project at a depth of 1,277 metres.
The working area is located 300 km off
the coast of Norway.
Rock varying in size from 1” to 5” has been installed to stabilize the Polarled pipeline.
Flexible fallpipe vessel Stornes can install rock
in water depths up to 1,500 metres.
Facts & Figures
Being the largest operator on the Norwegian continental shelf, international energy company Statoil is licence holder for numerous oil and gas fields and has several fields in development. Aasta Hansteen, discovered in 1997, is one of them. Recovering this valuable resource will be demanding, as the discovery was made far from land and outside the established infrastructure. The water is deep and the weather conditions challenging. Polarled is a new pipeline connecting Aasta Hansteen to the Norwegian mainland. The 480-kilometre gas pipeline facilitates the development of Aasta Hansteen and other fields in the Norwegian Sea. It is of vital importance that this pipeline remains stable and safely anchored to the seabed. Statoil contracted Van Oord to protect this Polarled pipeline by installing rock at a record-breaking depth of 1,277 metres. Flexible fallpipe vessel Stornes completed the first phase of these record subsea rock installation works in November 2014. Van Oord will execute the second phase of rock installation in this very deep water this year, when a total of approximately 300,000 tonnes of rock will be placed after the pipelines and templates have been installed.
Fossil fuel is the world’s largest energy resource. Recovering new oil and gas resources presents a big challenge. New developments are located outside the established infrastructure and in significant water depths. We even set a world record recently: in November 2014 Van Oord’s flexible fallpipe vessel Stornes installed rock at a record-breaking depth of 1,277 metres.