Oil Companies International Marine Forum (OCIMF) issued a new information paper entitled “Offshore Vessel Operations in Ice and or Severe Sub-Zero Temperatures in Arctic and Sub-Arctic Regions“.
The purpose of this paper is to provide guidance to operators and charterers of offshore support vessels employed for use in areas impacted by ice or severe sub-zero temperatures with the aim of encouraging high standards of safety and environmental protection for those operating in Arctic and Sub-Arctic regions.
Ice and severe sub-zero temperatures may impact on offshore vessel operations in many geographical areas. Operations in ice and severe sub-zero temperatures present vessel operators with unique risks and considerations. Operating areas are often remote with very limited navigational and support infrastructure, sea ice might be encountered year-round or seasonally and may include multi-year ice and severe sub-zero temperatures. Third party ice management may be required, depending on Ice Class and installed power of the offshore vessel. Due to the specialist nature of operations and navigation in these areas, the guidance in this paper is primarily aimed at project-orientated shipping supporting upstream activities and associated vetting decisions for spot employment.
By the very nature of their operations, work on offshore support vessels entails personnel working outside accommodation areas on deck. Wherever possible, crew exposure to the harsh environmental conditions should be limited by, for example, vessel design and adherence to established work/rest routines. Operators conducting operations in Arctic and sub-Arctic regimes should have procedures in place to address crew exposures to the anticipated conditions. For further information, reference should be made to the International Oil and Gas Producers Association (OGP) report No 398 The Health Aspects of Work in Extreme Climates.
Ice accretion
Ice accretion is a serious hazard for marine operations. It can be caused by sea spray or by fog, sea smoke, rain or snow. The most serious form of ice accretion is usually formed by sea spray but fresh water accretion from fog, rain or sea smoke can cause radar, aerial and insulator failures as well as rigging damage and consequential danger to those on deck.
The most obvious danger of sea spray ice accretion is that of vessel instability and, in extreme cases, capsizing. But there are other dangers and operational problems to consider including malfunctioning machinery, blocked vents and the physical dangers to crew members trying to work or rectify problems in such conditions. At present, there are few methods available to prevent icing and to quickly clear it should it occur.
Sea spray ice accretion occurs when wind and wave-generated spray comes into contact with cold exposed surfaces and the air temperature is below freezing. There are two general factors to be considered; environmental and vessel characteristics. These are briefly described below.
Ice types and conditions
Several forms of floating ice may be encountered at sea within the geographical areas covered by this paper. The most extensive is that which results from the freezing of the sea surface, namely sea ice, but mariners may also be concerned with ‘ice of land origin’ – icebergs, ice islands, bergy bits and growlers. Both icebergs and sea ice can be dangerous to shipping and their presence will impact on navigation.
Navigating in sea ice
There are many sea ice properties that can affect a vessel’s navigation performance. The most obvious is the thickness of the ice but other properties, such as hardness, are also important. Multi-year ice is normally harder than first-year ice owing to the amount of salt that will have leached out during warmer periods. There can also be differences in the hardness of first-year ice, depending on the formation process and source. The amount and type of snow cover on the ice adversely impacts the friction against the hull of a vessel.
It is recommended that Masters avoid or navigate with extreme caution when working in open water close to the leading edge of pack ice, particularly during rough weather. Sections of the ice edge are liable to break off, creating a danger to ships as they have the potential to strike a vessel above an ice strengthened belt, causing significant damage.
Anchoring in ice conditions can be hazardous due to the high loads that may be imposed on the anchoring system by drifting ice, which may lead to the anchor dragging and/or damage to the anchor, cable or windlass.
Offshore supply operations
It is important that the crew working on deck are kept safe and are able to retreat to warm areas. An assessment of environmental conditions including wind-chill exposure limits should be undertaken and shift routines should be adjusted to suit the prevailing working conditions to ensure that exposure is minimised.
Effective procedures should be in place to ensure that cargo deck areas are maintained clear of ice and/or snow. It is also important that clear access is maintained to cargo securing points. Drill pipes and casing carried as cargo should be provided with end caps to prevent water ingress and subsequent freezing.
When operating in conjunction with platforms, care should be exercised with regard to the hazards of falling ice emanating from the platform or from the cargo being lifted.
When handling bulk cargoes, hoses used will be vulnerable to damage through contact with ice and should therefore be kept under constant supervision and, preferably, should be raised clear of the ice using a crane. On completion of transfer operations, hoses should be thoroughly drained to minimise the potential for residues to freeze.
The vessel’s pumping performance when handling bulk cargoes such as brines, muds and cement should be evaluated, taking into account the operating temperatures. When handling dry bulk cargoes, driers fitted to compressors should be fully operational to ensure the air has a low dew point and the risk of freezing is minimised.
Source and Image Credit: OCIMF
For more information please the position paper issued by OCIMF by clicking on the image below:
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I had no idea that oil companies drill for oil in arctic and sub-arctic regions. That is very interesting. My question is though, how to they survey the region for oil? It must be very difficult to do so when you have ice all around. Not only do you have problems with surveying the region, but you have many elemental barriers as well, such as the freezing cold and ice everywhere.