bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of SAR Strategies in Norwegian and Russian Part of the Barents Sea
Authors: Berg T.E. , Selvik Ø. , Rautio R. , Bambulyak A. , Marichev A. 
Published: November 2016

Abstract
The rising level of industrial activity in the Barents Sea region will result in more SAR operations. Oil and gas companies develop their own emergency response organizations in order to obtain the governmental permits required to operate. Where commercial shipping and fisheries are concerned, emergency response operations will depend on the availability of governmental resources and vessels of opportunity when an accident occurs. Low sea and air temperatures require rapid response in the event of a maritime emergency. Transit speed of rescue units, improved search technology and improved technology for transfer of personnel from lifesaving appliances to rescue units all affect the probability of survival of personnel involved in a maritime emergency in the Barents Sea region
Pack Ice Loads on Seasonally Operating Semi-Submersible in the Labrador Sea
Authors: Thijssen Jan , Fuglem Mark , Dolny John 
Published: November 2016

AbstractSemi-submersible drilling platforms are typically moved off site given any threat of pack ice incursion. Operations in icy waters requires considerations of, amongst others, ice interations with the facility. The offshore industry will benefit from a standardized methodology to evaluate the capability of semi-submersibles in ice during drilling operations. Operators and drilling contractors are particularly interested in understanding how the drilling season may be extended into the shoulder season. This requires an understanding of variability in site-specific ice conditions throughout the year.Ice load analysis is needed for semi-submersible rigs operating in ice prone regions to determine ice strengthening requirements. Ship-based ice class rules can be considered for the design loads of the pontoons in transit conditions, but there is no standardized methodology for determining ice loads for the operational conditions. This paper focusses on the operational phase, where loads act on the vertical-faced columns. ISO 19906 (2010) offers a framework for determining sea ice loads in the form of a deterministic equation that has been established for fixed structures mainly operating on a year-round basis. The results will generally be quite conservative for seasonal operations. Consideration of ice exposure, to account for the limited drilling season, is permitted by ISO 19906 using probabilistic approaches, though no specific guidance is provided. Seasonal operations can be planned to avoid the most severe winter conditions, allowing for a reduction of the design level ice conditions. This reduction in the severity of sea ice that impacts semi-submersible columns should be accounted for in determining design ice loads. This paper demonstrates application of an analytical approach to include exposure considerations to estimate extreme ice loads for various drilling season extensions.An approach is demonstrated here for determining design sea ice loads to evaluate the capability of a semi-submersible in pack ice conditions. The approach considers the possibility of extended season drilling operations, rather than year-round operations, and may permit more efficient exploration in Arctic and sub-Arctic regions in the future. A study case is presented for a semi- submersible operating in the early ice season at a selected location in the Labrador Sea. The approach can be easily adopted for operations in other regions and other structure types, but is dependent on the availability of reliable data on ice conditions.
Near-Field Ice Management Tactics for Floating Drilling in Arctic Pack Ice
Authors: Hamilton Jed , Kokkinis Ted , Holub Curtis , Matskevitch Dmitri , Cheng Tao , Harris Matthew , Shafrova Svetlana 
Published: November 2016

Abstract
In order to be economically viable, Arctic floating drilling in high concentration pack ice requires very high confidence that ice interaction does not lead to costly, unanticipated emergency disconnections of the rig from the well. One of the foremost near-field ice management challenges is to maintain the station-keeping drilling rig within the managed ice channel throughout periods of complex changes in ice drift direction and speed. This entails precise, continuous re-positioning of the ice management fleet, which may be located up to several kilometers up-drift of the station-keeping drilling rig, in response to changing drift. While it may seem plausible to position up-drift ice management operations based on ice drift forecasts, forecasting unfortunately has insufficient precision to achieve the necessary level of reliability. To remedy this problem, ExxonMobil has developed systematic ice management command and control tactics that maintain the station-keeping drilling rig within the managed ice channel with high confidence. The tactics are based solely on the recent drift time history, and therefore eliminate any need for ice drift forecasting for near-field ice management operations. The tactics were proven in a series of near-field ice management tests conducted during the Oden Arctic Technology Research Cruise (OATRC 2015). OATRC2015 was performed by the Norwegian University of Science and Technology in cooperation with the Swedish Polar Research Secretariat and support and participation by ExxonMobil. Over a period of ten days during September, 2015, in which there were many complex Coriolis-driven ice drift loops and cusps and rapid drift direction changes, the methodology was able to successfully manage ice ahead of a fixed way point such that the point remained well within the managed ice channel at all times. The key features of the approach are described herein and include the use of variable length "arched racetrack" icebreaking patterns and an algorithm for continuously adjusting the position and size of the racetracks based on the measured ice drift speed and direction.
Design of a Shipboard Local Load Measurement System to Collect Managed Ice Load Data
Authors: Piercey Gerald , Ralph Freeman , Barrett John , Macneill Andrew , Jordaan Ian , Younan Adel , Fenz Daniel 
Published: November 2016

Abstract
Due to a lack of data, currently (and justifiably) conservative ice load assumptions are made in rig assessments allowing only very small floe sizes to contact non-Polar classed drilling rigs. In September 2015, in cooperation with the Norwegian University of Science and Technology (NTNU) and the Swedish Polar Research Secretariat (SPRS), ExxonMobil and C- CORE participated in the Oden Arctic Technology Research Cruise. A distinguishing aspect of this Cruise was: (a) performing ice management trials using two icebreakers, the Oden and the Frej; and (b) instrumenting the Frej, i.e. the secondary icebreaker and therefore collecting first-of-a-kind local ice load data during stationkeeping in managed ice. Unlike all prior data behind code pressure-area curves, which are based on transit in unmanaged ice and ship ramming, the new data are in managed ice field, representing true pressures and forces on a drilling or production vessel in a stationkeeping mode (moored, dynamically positioned (DP) or DP assist). This paper describes the design, installation and calibration of the Frej load measurement system. The system consists of an array of over 160 strain gauges installed over three panels on the bow and shoulder of the vessel. Prior to sailing, physical calibrations were performed as quality checks of the gauge installation and to benchmark finite element (FE) models used afterwards to convert measured strains into hull local ice pressures. More than 260 hours of local ice load data were collected throughout the program including measurements while stationkeeping in managed ice conditions in addition to actively managing ice and transit. The system remained operational through the entire field program without loss or damage to a single strain gauge. The data collected can contribute toward demonstrating the ability of existing rigs to resist some degree of managed ice, and hence can open the possibility for drilling season extension beyond open water, which can have a significant economic impact on arctic drilling. The resulting pressure-area curves will be the subject of a follow-up publication.
Improved Added Mass Modeling for Ship-Ice Interactions Based on Numerical Results and Analytical Models
Authors: Huang Yujian , Qiu Wei , Ralph Freeman , Fuglem Mark 
Published: November 2016

Abstract
Global ice loads at different locations on a ship during rams into ice are a function of ship motions and added mass in addition to the failure mode and strength of the ice. In the literature, various analytical added mass models have been used for ship-ice interactions, which could lead to significant differences in the prediction of global ice loads on ships. In this work, an improved added mass model has been developed based on numerical results and existing analytical models. Added mass coefficients of three ice-going ships, CCGS Amundsen, CCGS Louis S. St-Laurent and MVArctic, were estimated using four analytical added mass models. It was found that the differences in added mass coefficients predicted by these models are significant and enhancements can be made. A body-exact numerical simulation tool based on the potential-flow theory, MAPS0, has been used to compute the added mass coefficients of the three vessels in the frequency domain and the results were used for the development of the improved added mass model. The improvement in the load predictions has been demonstrated by applying the new added mass model to the three vessels.
Application of Upcrossing Rate Methodology to Local Design of Icebreaking Vessels
Authors: Ralph Freeman , Jordaan Ian , Manual Mike 
Published: November 2016

AbstractDesign of icebreaking vessels or ice-capable vessels must include consideration of extreme local ice pressures and exposure. Application of probabilistic methods used for data analysis, and then directly applied in design, with consideration of exposure is most useful. The Maximum Event (ME) Method is formulated for cases where ramming of ice is the dominant event. The peak pressures on a hull panel through the ram duration for each ram event is modelled. Data for each panel area are ranked and an exponential distribution fit to the tail of the ranked data. For design, we are then concerned with the maximum of n events expected in a specified period of time (e.g., a year). The random occurrence of ice along a route will also translate in to an annual number of expected impacts depending on ice and vessel dimensions. Vessel Ice classes would correspond to an annual number of impact events. This approach was used during the Arctic Shipping Pollution Prevention Regulation (ASPPR) revisions to validate maximum forces for different class vessels (e.g., a CAC4 vessel would be designed for 10-15 rams per year). For continuous-type interactions (e.g., a large floe crushing around a stationary vessel, or continuous icebreaking) an alternative approach is to use the Up-crossing Rate (UCR) Method. The number of local pressure upcrossings above a specific threshold on a particular panel area within a specified time (e.g., one year of operation) is determined. Exceedance curves for the UCR for increasing pressures on incremental panel areas are determined including an exponential fit to the tail of the distribution. For design, one only needs duration of interactions with the specified ice conditions through the year. The methodology was exercised to estimate local pressure parameters for transit segments during the ODEN 1991 trials. The greater the number of impact events and the longer the event duration, the greater the local pressures on panel areas. These high pressure zones occur and disappear, randomly shifting in location and intensity as fracture and spalling processes reshape the interaction area. For future development of the ISO design code, it is recommended that two modeling approaches be considered, the traditional ME method for short duration events and the UCR method for continuous interactions. The UCR method provides a simple means to design icebreaking vessels for extreme local pressures during continuous interactions. The method is also attractive for design of a stationkeeping vessel operating in broken ice where modeling individual floe interactions is not practical.
Using the Event Maximum Method to Further Analyze Full Scale Local Pressure Data
Authors: Manuel Mike , Ralph Freeman , Jordaan I. J. 
Published: November 2016

Abstract
Extreme values for local ice pressure are a primary consideration in the design of local structure for ships and offshore structures in arctic environments. ISO 19906 (2010) includes guidelines for a probabilistic approach in determining the local design pressure for Arctic offshore structures. However, the standard is vague in how it should be used. The probabilistic method employed in the standard is the event maximum method developed by Jordaan et al. (1993). It accounts for the expected exposure of the local structure to ice pressure and includes a constant, a, used to describe the relationship between local pressure and area. The constant a is derived in Jordaan et al. (1993) and extended in Jordaan et al. (1997) and reported in Taylor et al. (2010). The a-area relationship is based on the local pressure values from the very aggressive multi-year ridge rams of the CANMAR Kigoriak trial (1982). This leads to a very conservative a-area relationship and may be excessive for some ice conditions. This paper includes an explaination of the use of the event maximum method in ISO 19906. Local pressure data obtained through shear strain gauge systems from Polar Sea (1983) and Oden (1991) have been reanalyzed using the event maximum method (Jordaan et al. 1993, 1997). The data has been sorted by both ice thickness and ice concentration to investigate the existence of a trend between ice thickness and local pressure.
A Revised Basis for Iceberg Areal Density Values for Risk Analysis
Authors: Habib Kashfi , Hicks Michael , Stuckey Paul , King Tony 
Published: November 2016

Abstract
Iceberg areal density is one of the most important and challenging parameters to define accurately for offshore petroleum exploration. The two data sources for iceberg areal density considered here are aerial reconnaissance data collected by the International Ice Patrol (IIP) and iceberg charts which merge aerial reconnaissance data with other observations and model output. The IIP operates regular flights to monitor iceberg hazards to transatlantic transportation off the Canadian East Coast. The IIP and Canadian Ice Service (CIS) work together to generate daily ice charts year-round to provide the most reliable and timely information about the iceberg distribution by defining an iceberg limit to minimize risk of iceberg collision to transportation. The purpose of the iceberg charts is to promote safe maritime operations and to inform mariners about the latest ice conditions in navigable Canadian waterways and transatlantic shipping lanes in international waters. With navigational safety as its primary goal, the IIP develops the iceberg limit and distribution for vessels planning to avoid encountering icebergs completely. These warnings therefore are generally more conservative than on-site observations. The daily ice chart is created based on the data provided by various sources and is modified regularly by adding new sightings and applying drift and deterioration models to previous sightings. Among all the sources, aerial reconnaissance provides the most up-to-date information on iceberg conditions, and are generally conducted between February and July. For a better understanding of the influence of the data sources, iceberg frequency values using aerial reconnaissance data and charts were compared for a common period of time for several locations. Comparing the results, it was observed that results from aerial reconnaissance data analysis are typically lower than results from chart data i.e., more icebergs were reported in the ice charts than were sighted by aerial reconnaissance. This is consistent with IlP's conservative approach in reporting iceberg hazards to transatlantic mariners. Using the most appropriate source of data to identify the risk that icebergs pose for offshore petroleum production facilities is essential. The objective of this paper is to assess the discrepancies between data provided through aerial reconnaissance and that included in the daily iceberg charts.
Grand Banks Bundle
Authors: Hopkins D. 
Published: November 2016

Abstract
Oil and gas exploitation continue in two key harsh environment regions: Grand Banks, Newfoundland and Barents Sea, Norway. Although these regions have different challenges in terms of ice, cold temperatures, and winter storms; one common obstacle is short offshore installation windows. Mitigating a short installation window is a key motivator in considering the use of Pipeline Bundle technology.
Within the UK North Sea, Pipeline Bundles has been a key technology for Subsea 7 in many offshore field developments and expansions over the past 35 years. With the unique ability to be utilised in a number of applications, including: congested lay-down corridors, challenging seabed conditions, and the efficient incorporation of subsea processing elements; the technology offers a flexible design for any subsea field.
To export this key technology differentiator from the UK North Sea, Subsea 7 has conducted a feasibility study to investigate the use of Pipeline Bundles in the Grand Banks region. This paper discusses the various design considerations and installation options needed for the area as well as the technical readiness of the components of the Pipeline Bundle when matched against these requirements.
A way forward is then presented regarding the necessary Pipeline Bundle design and installation option for use in the Grand Banks.
Geohazards in Deepwater Sectors Offshore Newfoundland and Labrador Available for Parcel Nomination in 2016-2019
Authors: Piper David J. W. , Saint-Ange Francky , MacKillop Kevin , Campbell Calvin , Mosher David C. , Rashid Harunur 
Published: November 2016

Abstract
Several deep-water sectors offshore Newfoundland and Labrador are available for parcel nomination in the next few years. This paper summarizes the current availability of geohazard information from Geological Survey of Canada (GSC) data holdings, Open Files and published papers. It presents background geological information on controls on geohazards, and summarizes the significance of existing published geological and geotechnical data. It focuses on sectors NL01-LS, NL02-LS (southern Labrador Slope), NL02-EN (northern Orphan Basin), and NL01-SEN (Carson and Salar basins), with brief mention of NL-01-SN. It is based on field surveys by the GSC in the past decade, including multibeam bathymetry, high-resolution seismic, and piston cores. The information is applicable to E&P companies considering nominating parcels or submitting bids for leases and to the regulator as a guide to geohazards and sea-floor constraints to exploration and production.
Estimation of Ice Loads Using Mechanics of Ice Failure in Compression
Authors: Jordaan Ian , O’Rourke Brian , Turner Joshua , Moore Perry , Ralph Freeman 
Published: November 2016

Abstract
In the calculation of ice loads, reliance is generally placed on analysis of empirical data. The main reason for this is that the complex behaviour of ice under stress makes it difficult to use calculations based on mechanics directly in design. Ice is extremely brittle and prone to fracture, and develops areas of very high compression and confinement during compressive failure, which result in substantial changes in the microstructure and behaviour of the material. These are termed highpressure zones.
Progress in the analysis of ice failure using advanced methods of mechanics is reported. This has included studies aimed at understanding the behaviour of high-pressure zones. All work includes analysis of time-dependent effects, essential for a proper analysis of ice failure. The paper includes a discussion of the role of fracture and the development of high-pressure zones. Fracture processes are understood but the randomness of the flaw structure of ice in the field suggests that there is a strong variation in magnitude and position of high-pressure zones. This is supported by observations in the field on vessels operating in ice.
The analysis of high-pressure zones is outlined; these produce the high local pressures of great importance in design. As noted, very high pressures occur at the centre of the zones on small areas, of the order of 70 to 100 MPa, accompanied by very high confinement and shear. The response of the ice is profoundly altered under these conditions, as compared to virgin ice. Methods of damage mechanics have been used successfully to analyze the failure of high-pressure zones, and a distinct failure load has been obtained. The methods of mechanics require a non-classical approach that recognizes changes of material behaviour with time. A scaling rule related to the mechanics allows modelling on a smaller scale in the laboratory. Fracture events make the process of interaction highly variable in time. In the view of the writers of the present work, full time domain simulation of the process of interaction is not possible. A reasonable way to move forward is to combine the progress in high-pressure zone analysis with empirical analyses of high-pressure zone areal density and intensity.
Oil Exploration and its Relationship to the World of Trapped Micron Scale Fluids: A Review of the Applications of Fluid Inclusion Microscopy to the Study of Aqueous and Hydrocarbon Fluid Dynamics in Sedimentary Basins
Authors: Feely M. , Costanzo A. , Hunt J. , Wilton D. , Carter J. 
Published: November 2016

Abstract
Fluid inclusions are micron scale samples of aqueous and hydrocarbon fluids trapped in annealed microfractures developed during burial, or earlier in authigenic minerals e.g. quartz and/or calcite during cementation. Microscopic studies are carried out on specially prepared doubly polished fluid inclusion wafers (~ 150 microns thick) of well core, sidewall core and cuttings. Using a combination of transmitted light and UV light microscopy, laser Raman microscopy and microthermometry, facilitates the collation and comparison of fluid inclusion data. Textural and compositional data relating to the trapping history of fluids can be further constrained using P-T modelling software. The results of fluid inclusion studies of North Atlantic offshore basins i.e. Irish, and Newfoundland and Labrador offshore sectors highlight the use of these analytical and fluid modelling techniques. For example, Porcupine Basin aqueous basinal fluids trapped in cements are consistently of low to moderate salinity (&lt;10 eq. wt.% NaCl), comparable to those found elsewhere on the Atlantic margins e.g. UK Rockall, West of Shetland region, and in the Jeanne d'Arc Basin offshore Newfoundland and may reflect the paucity of evaporites at depth in these regions (Parnell et al., 1999, Parnell et al., 2001 and Feely and Parnell 2003). Migration of at least two chemically distinct hydrocarbon fluids occurred post cementation, as lateral flow along Jurassic sandstones with limited vertical flow along faults (Conliffe et al., 2009). In the Saglek Basin offshore Labrador both monophase (liquid) and two-phase (liquid + vapour) hydrocarbon fluid inclusions occur in the Cretaceous Markland Formation. The two-phase hydrocarbon inclusions yield homogenisation temperatures of ~80°C. The aqueous fluid inclusions represent low temperature (~100°C) and low salinity (~5 eq.wt% NaCl) fluids, and are similar to those recorded in the Porcupine Basin offshore Ireland. P-T modelling of these fluids indicate trapping pressures and temperatures of ~300 bars and ~110° C.