About my work: Reducing the impact from sea ice on marine operations in the Arctic

The reason for me being on the Arctic Ocean 2016 research cruise is primarily to gather data for my PhD research work. I have promised a post about my work, so let me tell you a bit about what I am doing.

I started my PhD at the Norwegian University of Science and Technology (NTNU) in October 2015, related to technology and marine operations in the Arctic. The preliminary title of my PhD thesis is “ice drift prediction and mitigation of impact from sea ice on marine operations”. So what does this mean? In order to explain, let me give you some background and explain some key terms.

We expect to see an increase in marine activity in the Arctic in coming years, as there has been a trend towards less sea ice in recent years. Marine activities include activities such as fisheries, ship transport or “blue mining”, mining on the seabed using vessels. Furthermore, search and production for hydrocarbons, oil and gas, in the Arctic will most likely increase in the coming years.

In 2009, the US Geological Survey estimated that more than 25 % of the world’s remaining hydrocarbon resources are located in the Arctic (Gautier et al., 2009). Therefore, as sources of easily available hydrocarbons are getting scarcer, the search and production in the Arctic will intensify. Searching for and producing oil in the Arctic have already been ongoing since the 1970’s, and developments exist in the Beauford Sea (Canada/USA), the Kara Sea (Russia), and the Barents Sea (Russia/Norway).

Marine operations is a term used to describe activities performed by working vessels at sea. These operations are necessary when developing an offshore field. The term is broad, and includes activities such as heavy lifting, barge towing with cargo, moving of rigs (platforms) and installation of subsea cables and pipelines.

For many marine operations, stationkeeping is key. Stationkeeping is a term used when a ship or rig wishes to maintain their geographical position over time. The position can be held using thrusters (propellers) only, or a combination of thrusters and anchors, more common for larger floaters. Stationkeeping can be done manually, where the officer on the bridge control the thrust. However, high accuracy positioning require advanced dynamic positioning (DP) systems. The DP system counteracts the environmental forces pushing on the vessel, such as waves, wind or ocean current, by controlling the thrusters autonomously, meaning without human interference.

The photo below shows an operation where stationkeeping is required. For different reasons, not all offshore oilfields have pipelines for transporting oil to shore. In order to transport the oil to shore, shuttle tankers sail back and forth. Loading an oil tanker at sea can happen in different ways. One way is buoy loading, which is depicted in the photo. The oilfield have a floating loading buoy nearby, which the tankers can come up to, connect to and load from. This way, the tankers do not have to come close to the rigs, and the risk of a serious collision is lowered. Loading the tanker take several hours, and often more than a day.

bouyloading

Photo: A tanker loading oil from a buoy in ice conditions. The two icebreakers are breaking the ice floes into smaller, more manageable sizes (picture from http://www.lukoil.com)

The tanker needs to stay in position close to the buoy, but not too close. The tanker cannot get too far away either, as the tension in the loading hose could get too high and the hose can break. The buoy can rotate 360 degrees, so the vessel can position itself with the bow towards the ice drift regardless of which the direction the ice comes from. The two smaller vessels in the photo are icebreakers who breaks the ice floes in smaller pieces. Why? I will get back to that soon.

Marine operations can be challenging to plan and execute already in open water. The presence of sea ice makes everything even more difficult. The sea ice introduce additional forces, as ice will drift against, hit, and push against the hull. If there is a lot of ice, it can accumulate and push against a structure with great force. Stationkeeping in sea ice is challenging, as existing DP systems have difficulties handling the additional ice forces. Therefore, it is desirable to reduce the forces from ice on the vessel as much as possible. Now, this is a key concept in my work. If you remember, the title of my thesis said “mitigation of impact from sea ice on marine operations”. This essentially means to reduce the forces on ships/rigs from the ice. But how can you reduce the ice forces?

Any activity done to avoid or reduce the forces from ice is called “ice management”, defined by Eik in his paper from 2008. Ice management includes both physical actions, such as using icebreakers to break the ice or towing of icebergs, and non-physical actions such as detecting, tracking and predicting the ice drift. In the loading from the buoy, both having the bow up against the ice drift and breaking the ice floes reduce the ice forces on the tanker, and is ice management.

acex

Photo: From the ACEX expedition in 2004, some of the most ice-capable icebreakers in the world; Vidar Viking, Oden, and Sovetskiy Soyuz from near to far. The expedition drilled and recovered deeply buried sediments from the Lomonosov Ridge (picture from Moran etl. al., 2006)

Ice management requires information on the ice drift; the speed of the ice and which direction it is coming from. However, the ice drift in the Arctic can change both in direction and speed quite rapidly, and this can be difficult to predict. In 2004, the three-icebreaker expedition ACEX set out to the Arctic to drill cores from the Lomonosov Ridge. The photo above shows the three icebreakers sailing in ice. Moran and his co-authors wrote a paper on in 2006. The icebreakers were some of the most ice-capable in the world; Vidar Viking, Oden and Russian nuclear-powered icebreaker Sovetskiy Soyuz.
Vidar Viking was converted to a drillship for this expedition, and performed the drilling while stationkeeping. Oden, on which I am now (read why here:
https://runaskarbo.wordpress.com/2016/08/24/why-we-are-here-a-brief-introd uction/), and Sovetskiy Soyuz performed ice management by reducing the sizes of incoming ice floes through sailing in circular patterns. The drilling was successful, but Vidar Viking did not manage to stay on DP for the drilling operations, and stationkeeping had to be done manually. They managed to keep within a circle of 50-75 metres while drilling in 1100-1300 metres water depth. They experienced that the most difficult situations to keep the drillship on location was when the ice drift was changing. So how can we track and predict the ice drift?

As of today, tracking the ice drift is done manually by placing physical GPS trackers on the ice by helicopter. This is high risk, expensive and has a high carbon footprint. Thus, systems that are more autonomous are desired. This is where my work come in. In my PhD work, I will work on using onboard systems such as cameras and the radar to detect and track the ice drift around the ship. That way we can predict the forces from the ice hitting the ship. Predicting the forces means that we can know in advance how much thrust to send to the propellers on the ship, or how to adjust ice management operations with ice breakers. One of my colleagues, Øivind Kjerstad at the University Centre of Svalbard, has already developed an algorithm to track ice drift using the onboard ship radar. I will work further on implementing his and others’ work with other sources of information about the ice drift. I will also work with information from satellite Synthetic Aperture Radar (SAR) images, which can give information on the regional ice drift.

Now, the reason I am on Oden these last weeks (and still one week to go) is to collect data to use in the work I described above. I collect images from the radar screen, to retrieve the ice drift close to the ship using the model already developed. In the future, my goal is to have a model that can run in real-time. Until then, I can use these images as input to the model as if it was in real time. In addition to the radar images, I am collecting meteorological data such as wind, clouds and temperature, which play a role in the ice drift. Furthermore, we have 360 degree and 180 degree cameras on Oden. Actually, it is several cameras, and we stitch the together images to panoramas, like shown in photo 3. The cameras are recording continuously for the whole trip, saving images every five seconds. I can use the cameras to see i.e. ice concentration, meaning how many percent of the water is covered by ice. I will also use the camera images to track the ice drift and to identify ice features such as ice ridges and icebergs. (Another blog post coming up on sea ice and different kinds of ice features later.)

180deg-2

Photo: Screenshot of a live-stitched 180 degree panorama from the Arctic Ocean 2016 research cruise on icebreaker Oden (courtesy of Hans-Martin Heyn, NTNU)

So that’s it, that is why I am here! Of course, the cruise is also a very good opportunity to actually experience and understand the Arctic, sea ice and icebreaking. I have done field work on sea ice before in Svalbard (a post on that is coming later), but actually being up here in the Arctic Ocean is different. To sit in an office and write about operations in ice without having seen or experienced the ice is abstract. Therefore, I am very happy that I got this opportunity to join this cruise. And I am hoping for more to come! PhD work can take you many exciting places!

img_2788

Photo: Me checking on the the equipment that collects the radar images on the bridge of iceabreaker Oden

 

 

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3 thoughts on “About my work: Reducing the impact from sea ice on marine operations in the Arctic

  1. Pingback: First sea trials in ice completed | Runa Skarbø

  2. Pingback: Best moments of 2016 | Runa Skarbø

  3. Pingback: Great moments and experiences of 2016 | Runa Skarbø

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