In 2000, the International Standards Organisation (ISO) approved the development of an International Standard for Arctic Offshore Structures. Canada, having active committees in place for such an activity, took the initiative to propose and coordinate the new work item to ISO. In response to the Canadian initiative, in 2002 the ISO Technical Committee 67 (TC67), Sub-Committee 7 (SC7 - Offshore Structures) approved the development of a new standardentitled " Petroleum and natural gas industries - Arctic offshore structures??. In addition, the developers of the new standard were tasked with the secondary objective to harmonise existing international offshore codes and standards related to Arctic structures. SC7 established Working Group 8 (WG8) in response to this approval and WG8 held its first meeting in July 2002, in Toronto, Canada. All countries with regions in ice covered waters, or with an interest in these regions, were requested to provide country representatives and technical experts to staff both WG8 and the Technical Panels formed by WG8 to actually prepare the document. The technical work was initiated in 2003 and the completed document, ISO 19906 Arctic Offshore Structures, is scheduled to be approved by the ISO member countries in late 2010. The approved Standard specifies requirements and provides recommendations and guidance for the design, construction, transportation, installation, and removal of offshore structures, related to petroleum and natural gas activities in arctic and cold regions. The objective of the document is to ensure that offshore structures in arctic and cold regions provide an appropriate level of reliability with respect to personnel safety and environmental protection to the owner and to society in general. While the document does not apply specifically to mobile offshore drilling units, the procedures relating to ice actions and ice management contained herein are applicable to the assessment of such units. This paper provides a brief history of the document preparation as it relates to country and industry involvement, development of technical input, editing and review processes undertaken and acceptance of the document by ISO and its participating members. Background and incentive By 2000, several factors emerged that together provided the incentive for the development of a new and global standard for arctic offshore structures. The formation of an international working group was proposed to develop an International Standard which would harmonise existing regional and national codes and standards and also update the provisions to include the latest agreed knowledge and technologies. Countries participating in WG8 agreed to view the new ISO Standard as a replacement for their existing codes and standards.
Aerial photography has had many applications since it was first obtained from manned balloons in the US Civil War to map the positions of enemy lines and troop locations. Early applications centered on military use, but with the lowered cost and availability of civilian aircraft after World War II, commercial applications (terrain mapping, urban planning, resource discovery and development, etc) have grown. The application of stereographic techniques to aerial photography has allowed the third dimension, i. e., height, to enter into commercial applications such as terrain mapping, surface mining, logging, urban planning, etc. On an Arctic scientific level, aerial photography has been used to map glaciers, ice edges and ice features. Using stereographic techniques, ice and iceberg volumes and mass could be estimated. Kiakowski, et al, 1982 used this technique to determine iceberg mass off Newfoundland on the eastern Canadian coast as part of the effort to develop iceberg design criteria for the Hibernia structure. Lovas et al, 1993 used similar techniques to estimate iceberg mass in the Barents Sea off northern Norway. In offshore Alaska waters, aerial mapping and stereo-photography techniques were first used by the US Air Force to discover and map ice islands in the 1950s. Later the oil industry employed aerial photography to map the location of sea ice and ice features that could affect offshore exploration and development. Stereographic techniques were used to the estimate the size of ice ridges. Multiyear programs were funded by industry prior to offshore lease sales in the US Beaufort and Chukchi Seas to develop ice design criteria (such as ridge height and width) and to plan for logistical operations (parameters required included number of ridges per mile, percent surface deformation, etc). Shell Oil Company is presently in the process of planning for the development of offshore leases in both the US Beaufort and Chukchi Seas and as part of its activities has incorporated stereographic analysis of aerial photography. Imagery has been obtained for three years already and the analysis results have been used in both EER planning and technology development and logistical considerations for the production phase.
An area of concern for any offshore oil development beyond the "transition zone", the zone where multi-year ice and landfast ice meet, is Escape, Evacuation and Rescue (EER). Due to the unique environmental conditions, e.g large ice ridges, conventional evacuation methods such as lifeboats may not be sufficient. The unique environmental challenges in the Alaskan OCS and their potential impact on EER will be described. A feasibility assessment focused on the secondary evacuation component of EER will also be described. This assessment consisted of establishing performance standards related to the expected operating environment, identification of proven and novel evacuation methods, evaluation of these methods versus the performance standards, and prioritization of future work. Finally, recently-conduted data collection and analysis and technology maturation studies related to EER will be discussed.
The new ISO 19906 Arctic Offshore Structures standard contains provisions relating to a number of different types of offshore oil and gas structures in the Arctic and in other cold regions. Its provisions supplement those of ISO 19902 (steel offshore structures), ISO 19903 (concrete offshore structures), ISO 19904–1 (floating offshore structures) and other standards in the ISO 19900 series. This paper focuses on important arctic provisions and on how the standard can be used in conjunction with the other ISO offshore structures standards. Issues dealt with include features of arctic and cold regions; when the standard should be used; types of ice actions and how they should be applied; ice actions in the context of other physical environmental actions; manmade islands; subsea installations; ice data collection; monitoring; interpretation and analysis; ice management systems and operational aspects of arctic structures; and low temperature materials and equipment. Introduction Background Many of the structure design concepts used in arctic regions are similar to those in other areas and the same design principles apply. Nevertheless, the arctic environment poses a number of additional challenges due to marine icing on exposed surfaces, actions from sea ice and icebergs, structural vibrations as a result of ice actions, ice rubble encroachment, and brash ice build-up from icebreaker operations. In many cases, special operational procedures are required in harsh environmental conditions, which need to be factored into the designs. As a brittle solid, ice can exert considerable pressure over small contact areas, frequently exceeding average values over the loaded area. Local design requirements for ice are an integral part of the design process. It is because of the above issues that the ISO 19906 standard [1] was developed and, because their implementation can differ from standard practice, is why the present paper reviews its application. Terminology The ISO series has some particularities in terms of terminology with respect to North American usage. The main one is the use of the term "action" instead of "load", which is a more general term that could imply a load, an acceleration or a displacement. The characteristic value of an action or parameter is one that has a specified annual probability of being exceeded, which is often interpreted as a return period value. The representative value of an action is a characteristic value or some other value that is used for design.
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