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Iceberg Drift Forecast Requirements for Offshore Platforms Utilizing Facility Side-Tracking to Avoid Impacts

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Abstract

A number of solutions have been successfully implemented for producing oil and gas off Canada’s east coast, where impacts by icebergs are a possibility. In future, as operators move further offshore to deeper water and further north where the numbers and sizes of icebergs may increase, new solutions for avoiding impacts will be required to limit ice strengthening requirements and ice related downtime costs. A potential solution is the use of facility side-tracking, where a floating system is designed to move laterally to avoid approaching icebergs. This paper discusses the issues involved including the need for improved short-term iceberg drift forecasting. Copyright © 2015 by ASME Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

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Article
As the number of oil and gas players in Arctic and sub-Arctic regions increases, so do the suite of technology-based capabilities for cold region operations. Advances are being made in remote sensing, ice management, and ice engineering. R&D targeted to increase our understanding of the ice environment and ice mechanics is reducing uncertainties relating to ice loads. C-CORE and partners have been developing and providing technical solutions to most recent oil and gas initiatives facing the challenge of sustainable development in ice covered regions. Using this work as background, this presentation will highlight recent and imminent technological advances providing near-term improvement in the economics of cold ocean hydrocarbon production. Background Offshore oil and gas exploration began on the Grand Banks of Newfoundland in 1966 with the first major discovery, Hibernia, occurring in 1979. The discovery of Hibernia was the result of a joint exploration venture by Chevron and Mobil. Other major oil and gas discoveries on the Grand Banks followed with Hebron in 1981 and the White Rose and Terra Nova Fields in 1984. First oil was produced from Hibernia in 1997, Terra Nova in 2002, White Rose, 2005 with Hebron expected to be 2017-18. A number of R&D initiatives were undertaken in order to develop these resources safely and in the most cost effective manner possible. In the early 1980s comprehensive data collection programs were initiated by Mobil to develop a design basis for the Hibernia development (Dobrocky, 1984). Aerial surveys were conducted for above water iceberg characterization (size and mass) as well as iceberg profiling for below water geometry for mass. In 1996, Grappling Island iceberg impact experiments were carried out; the first ever iceberg impact experiments (Ralph et al, 2004). Research and development into ice mechanics and design load algorithms pioneered by Dr. Jordaan at the Ocean Engineering Research Center at Memorial University Canadian Offshore Design for Ice Environments (CODIE) project have made a tremendous impact in design for these harsh environments (CODIE I, 1997 and CODIE II, 2003). More recently, an improved understanding of ice mechanics and failure processes have led to an improved basis for global design loads based on a reduced iceberg pressure on large contact areas from 6.0 MPa used in the Hibernia design basis to a still conservative 1.5 MPa presently used for Hebron studies. From 1999 to 2005, C-CORE led a comprehensive Ice Management R&D JIP addressing technology challenges relating to detection and towing. Research and development continues with improvements and optimized methods for ice management (detection, forecasting, threat analysis, decision-making and iceberg towing), the modeling of ice management effectiveness for design, and improved methods for iceberg collision and design load analyses.
Article
In the past 10 years developments in technology and the opening up of new frontiers, combined with a demand to move into greater water depths have resulted in considerable increase in the use of floating facilities for offshore oil production. The Terra Nova Development has and will establish a number of project "firsts" including the first FPSO to operate in North American waters and the first to operate in a harsh North Atlantic environment frequented by sea ice and icebergs. Also stereotypical of this region are cold air and water temperatures, seasonal fog, and heavy seas. Overcoming these challenges has required Terra Nova to adopt the lessons learned from pervious FPSO developments in the North Sea, while using both proven and new technology, and utilizing the benefits on an alliance-based contracting approach. The result is a unique development solution with a number of lessons learned. Introduction The Terra Nova oilfield is located approximately 350km (220 miles) east-southeast of St. John's, Newfoundland, 35km (22 miles) southeast of the Hibernia oilfield in a water depth of 90 to 100m (295-330ft.). Figure 1 shows the field location. The total recoverable oil reserves in the field are estimated by the Canada-Newfoundland Offshore Petroleum Board (CNOPB) to be some 64?106m3 (400 million barrels). The top of the reservoir is located 3,200m (10,500ft.) below the seafloor. The field is made up of three geological fault blocks: the Graben, the East Flank and Far East as shown in Figure 2. Only the Graben and East Flank blocks have been delineated. Twenty-four wells are proposed for Graben and East Flank: 14 producers, 7 water injection and 3 gas injectors. If further delineation drilling in the Far East block, which is planned for 2002, locates commercially viable hydrocarbon reserves, an additional 5 producers and 5 water injectors may be required. The Terra Nova field development concept is shown in Figure 3. An ice strengthened, double-hulled Floating Production, Storage and Offloading (FPSO) facility with subsea wells and gathering system will be used for the development of the Terra Nova field. Development wells are being drilled using the mobile semisubmersible drilling unit "Henry Goodrich," through seven subsea templates placed in four 10m deep glory holes, used to protect the wellheads and xmas trees from scouring icebergs. Trenched and rock bermed flowlines connected to flexible risers will link the subsea wells to the FPSO. Crude will be offloaded by a dynamically-positioned shuttle tanker positioned at the stern of the FPSO. Terra Nova - A Project of Firsts The Terra Nova Development has set a large number of "firsts" which have significantly contributed to the challenges in the execution of the project. These "firsts" are varied in theme and include:First FPSO development on the Grand Banks and only the second offshore oil development on the challenging Grand Banks of Newfoundland.First offshore facility in Canada to be certified to both offshore petroleum and shipping regulations.First fully-automated quick disconnectable turret and riser system on a FPSO.
Article
As part of an early engineering study, a conceptual design of aproduction and drilling concrete gravity-based structure (GBS) for the West Bonne Bay (WBB) field offshore Newfoundland is compared with Hibernia's as-built results. The optimization of the WBB structure shape and dimensions allowed moderate steel reinforcement to be used and more than 75% of the concrete volume to be slip formed. Cost estimates were derived. The total scoping cost estimates for the construction and delivery of the WBB GBS concept have been estimated at about a third of Hibernia's cost. Savings resulted from the following areas:Lower ice and wave design criteriaEngineering and design of a single concept with a simple structural geometryImproved civil construction operations due to slip forming and moderate steel reinforcementSingle union contract for Bull Arm construction facilities in NewfoundlandIntegrated client and contractor team and common project management processesReduced mechanical outfitting quantities based on a lower number of wells and utility decks Introduction In 1995, Amoco Canada acquired two leases, East Flying Foam and West Bonne Bay, offshore the East Coast of Newfoundland in the Grand Banks area1. The WBB field is located 365 km ESE of St. John's, 20 km NE of Terra-Nova and about 50 km SE of Hibernia in 95 to 105 m of water (Fig. 1). Amoco Canada drilled its first well at that location in 1997. In 1996 and 1997, an engineering study2 was conducted to evaluate and appraise innovative alternatives to Hibernia's GBS3,4 and Terra-Nova's steel FPSO5. One concept selected amongst those alternatives, the concrete GBS, was designed6 using Hibernia's experience7,8,9. The results of a visit to the Bull Arm construction site in 1996 and data obtained from other GBS projects in the North Sea6 also provided vital information to this study. This paper presents the results obtained from the comparison of Hibernia and the WBB GBS concept. A second paper10 (OTC 11021) describes in detail the design of the WBB GBS. Design Criteria Terra-Nova11 ice, geotechnical and wave design criteria12 were used for this study. The WBB specific data were not available at the time of the study. The use of WBB specific criteria in the future may provide additional optimization and savings. For example, probabilistic ice loads derived for the WBB site were found to be lower than the deterministic loads estimated for Terra-Nova. In addition, if the distance between the top of the WBB GBS storage cells and waterline could be increased, a significant reduction in the global wave load could be achieved. Global Wave Loads A maximum wave height (Hmax) of 30 m and wave period varying between 17 seconds to 21 seconds were used. For monolithic structures with a large water line diameter, maximum wave loads are sometimes sensitive to the wave period. While the expected value is about 19 seconds, variations on either side were also checked in order to determine the maximum load. Hibernia's Metocean conditions were similar to those at Terra-Nova. Hibernia's 100-year wave load of 1,500 MN was higher by about 10% due to the WBB GBS narrower waterline diameter (25.4 m vs 106 m) as shown in Figs. 2 and 3. It is possible that further reduction can be achieved with more advanced analysis techniques and further design optimization6.
Book
This volume brings together the results of all salient research development in ice engineering, from smaller scale to full size tests on ice strength and ice mechanics which is essential criteria for the design of safe, cost effective structures. Much of the data has been released from confidential industry files and thus allows, for the first time, a full appraisal of the subject. Contents include - Types and Distribution of Ice, Mechanical Properties, Measurements of Ice-Structure Interaction, and Analysis of Ice Failure and Design Ice Loads. This work is completed with a full literary review and subject index.
Article
The Program of Energy Research and Development (PERD) has been funding development of the Iceberg drift and deterioration model in two areas: Improved Iceberg forecasts and Improved bergy bit guidance. The focus of the Improved Iceberg forecasts project is to develop improved iceberg information for the marine community in general and more specifically to the energy production sector. This will be accomplished by developing an improved operational iceberg modelling system running at the CIS. The focus of the Improved bergy bit guidance project is to develop improved understanding of iceberg calving mechanisms and bergy bit drift and deterioration and develop a standalone model that end-users can use. The information will be presented to interested tanker captains during training sessions or through training focused reports. Canadian Ice Service (CIS) has contracted Canadian Hydraulics Centre (CHC) to develop an Iceberg drift and deterioration model and provide upgrades and maintenance to the model. The aim of this reports is to summarize what has been achieved 2009/2010, what is remaining, and identify key issues and practical way forward. no yes
Evaluating Iceberg Towing Operations with Respect to Impact Avoidance
  • M Fuglem
  • P Stuckey
Fuglem, M. and Stuckey, P., 2014, Evaluating Iceberg Towing Operations with Respect to Impact Avoidance, Oceans 2014.
White Rose: Overview of Current Development and Plans for Future Growth
  • P Norman
  • G Lochte
  • S Hurley
Norman, P., Lochte, G. and Hurley, S., 2008. White Rose: Overview of Current Development and Plans for Future Growth, ISOPE.
Petroleum and Natural Gas Industries -Arctic Offshore Structures
  • Iso
ISO (2010) ISO 19906:2010. Petroleum and Natural Gas Industries -Arctic Offshore Structures. International Standards Organization.
Manual of Standard Procedures for Observing and Reporting Ice Conditions
MANICE, 2005, Manual of Standard Procedures for Observing and Reporting Ice Conditions, Canadian Ice Service.