bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ridge Loads on Wind Turbine Structures
Authors: Croasdale K. , Allyn N. 
Published: October 2018

AbstractWind turbine towers are being planned in ice covered regions subject to pressure ridges (e.g. the Great Lakes). Conical collars are often employed to reduce ice loads from level ice and their associated dynamics. For level ice, downward breaking cones have some advantages. It is not clear if this is the case for pressure ridges. This paper presents an improved method for ridge loads on wind turbines with downward breaking cones and makes comparisons with upward breaking cones.First year pressure ridges can be formidable ice features and usually control design ice loads in the sub-Arctic. Important components of a ridge creating ice loads are the consolidated layer at the surface (which is considered as solid ice) and the ridge keel below consisting of ice rubble, but much thicker. The load due to the consolidated layer is usually derived as if it is thick level ice. On a cone, methods for level ice assume it can be idealized as a plate on an elastic foundation (the water) and equations have been developed for upward and downward breaking cones. But for a ridge on a downward cone, to break the consolidated layer downwards requires it to be pushed into the keel rubble below. This will have a different foundation modulus than water buoyancy. A method is developed to account for this difference. The method uses an iterative approach to determine the point of breaking of the consolidated layer (and associated load) accounting for the ridge geometry, keel rubble shear strength, the flexural strength of the consolidated layer and the buoyancy forces. The keel loads on the vertical shaft below the conical collar are based on the method currently in ISO 19906 (2010) but modified to add the effect of additional rubble in the keel from breaking the consolidated layer downwards.In examples, it is shown that the breaking force can be about twice that of breaking the consolidated layer without the keel present. This might be seen as a disadvantage for downward breaking cones vs upward breaking. However, it is also shown that the clearing forces on an upward cone are higher; which tends to balance out the lower breaking force. Example loads are given on typical wind turbine bases due to typical ridges. Upward and downward breaking configurations are compared.The paper provides new methods for ice loads due to ridges acting on wind turbine structures not currently covered by existing methods.
Rigid Foam as an Engineered Material
Authors: Halcomb Steven , Oakland Bryan 
Published: October 2018

Abstract
The traditional use of extruded polystyrene (XPS) rigid foam insulation has been to control heat flow between building living space and outside environment; however, new information reveals additional ways XPS rigid foam insulation can be used in heavy load roadway, railbed, and airfield applications. The objective of this paper is to provide engineers with a better understanding of the behavior of rigid foam as an engineered insulation material to support transportation infrastructure in cold regions.
Numerous aspects of foam application and performance are discussed in this paper. Aspects include equivalent thermal resistance of foam vs. soil, normalized stress-strain curves of various rigid foam ultimate compressive strengths, cost comparisons between rigid foam and fill, and recent testing results of rigid foam when applied loadings exceed the ultimate compressive strength under repeated loadings. Testing approach was designed to consider loading associated with heavy equipment active in oil and mining operations.
Historic design recommendations for use of rigid foam in bearing considerations has been the inclusion of a sustained dead load from which a reduced live load is then utilized. The reduced live load presents challenges in roadway and runway applciations as more fill is required to reduce applied surface loads to lower values, thus disqualifying XPS as a viable insulation solution to support pavement structures under heavy live loads. With the introduction of new data, analysis, and interpretation, XPS is shown to provide a cost-effective thermal barrier between the subgrade and road surface for heavy loads when compared to fill that is sourced far from the construction site.
The recent testing of both extruded and expanded polystyrene under heavy and repeated loadings, with thermal resistance comparisons, leads to additional understanding of rigid foam as an engineering material.
Ice Clearing to Support Near-Field Operations
Authors: Kennedy Allison , Harris Trevor , Reid Veronica 
Published: October 2018

Abstract
Ice management is an important consideration for any offshore petroleum operation conducted in an area that could encounter sea ice. Ice management could be performed for a number of reasons: to reduce global ice loads on the installation, to avoid ice interaction with underwater components such as risers or turrets, or to allow for close proximity operations such as loading / offloading, manning / de-manning, or evacuation in the case of an emergency event. The purpose of this project is to provide baseline information relating to ice clearing operations conducted in pack ice conditions. This information includes outcomes of different ice clearing operations in terms of loads on a GBS structure and ice concentration upstream of the GBS structure. It also includes loads measured on the support vessel that is conducting the ice clearing operations for a subset of the clearing techniques considered.
To investigate this problem, model testing experiments were conducted in NRC-OCRE's ice tank located in St. John's NL, Canada. These experiments involved systematic testing involving various pack ice conditions representative of the Grand Banks area and two models: a support vessel and a GBS structure. The environmental conditions included: two ice concentrations, two ice piece sizes, and two ice piece drift speeds. Four ice clearing techniques were tested in each condition. The ice clearing techniques included two fixed position tests; where the support vessel was held in place upstream of the GBS using flexible mooring lines and two free running tests; where the support vessel was remotely controlled and maneuvered upstream of the GBS.
Results are provided in terms of loads measured on the GBS model with clearing support, loads measured on the support vessel during the fixed ice clearing operations, ice free zones created upstream of the GBS and aft of the support vessel during ice clearing tests, reductions in GBS loads due to ice clearing operations, reductions in ice concentration upstream of the GBS due to ice clearing operations, and a summary of ice events that led to large pack ice loads. The significant factors that influenced each result were also identified.
These results complement existing literature relating to physical ice clearing operations by providing the outcomes of systematic testing in different ice conditions which is available in public domain. These results could be used as benchmark values for design or numerical model validation. In addition, they could provide insight to operators, regulators and academia to support informed decision making regarding the level of ice management support required in different operating environments. All dimensions and test results in this paper are provided at full scale value.
Experimental Investigation of Low Salinity Waterflooding to Improve Heavy Oil Recovery from the Schrader Bluff Reservoir on Alaska North Slope
Authors: Cheng Yaoze , Czyzewski William , Zhang Yin , Dandekar Abhijit , Ning Samson , Barnes John 
Published: October 2018

Abstract
Alaska North Slope (ANS) contains vast resources of heavy oil which have not been developed efficiently using conventional waterflooding. Recently, low salinity waterflooding (LSWF) has been considered to enhance oil recovery by reducing residual oil saturation in the Schrader Bluff heavy oil reservoir.
In this study, lab experiments have been conducted to investigate the performance of LSWF in heavy oil reservoirs on ANS. Fresh-state core plugs cut from preserved core samples with original oil saturations have been flooded sequentially with high salinity produced water, low salinity water, and softened low salinity water. The cumulative oil production and pressure drop across the core plugs have been recorded by the AFS-300 coreflooding system. The oil recovery factors and residual oil saturation after each flooding have been determined based on material balance. In addition, restored-state core plugs saturated with heavy oil have been employed to conduct unsteady-state displacement experiments to measure the oil-water relative permeabilities using high salinity produced water and low salinity water, respectively.
It has been found that the core plugs are very unconsolidated, with porosity and absolute permeability in the range of 33 – 36% and 155 – 330 mD respectively. Produced crude oil sample having a viscosity of 63 cP at ambient conditions was used in the experiments. The total dissolved solids (TDS) of the high salinity produced water and the low salinity water are 28,000 mg/L and 2,940 mg/L, respectively. After softening, the TDS of softened low salinity water has little change, but the concentration of Ca2+ has been reduced significantly. The residual oil saturations are reduced gradually by applying LSWF and softened LSWF successively after high salinity water flooding. On the average, LSWF can improve heavy oil recovery by 6.3% of original oil in place (OOIP) over high salinity water flooding, while the softened LSWF further enhances the oil recovery by 1.3% OOIP. The pressure drops observed in the LSWF and softened LSWF demonstrates more fluctuations than that in the high salinity water flooding, which indicates potential particle migration in LSWF. Furthermore, it was found that regardless of the salinity the calculated water relative permeabilities are much lower than the typical values in conventional rock-fluid systems, implying more complex interactions between the reservoir rock, heavy oil, and injected water. This study provides fundamental lab data for evaluating the technical and economic benefits of LSWF in heavy oil reservoirs on ANS.
Usage of Unmanned Aerial Vehicles for Iceberg Surveying and Monitoring - Preliminary Results
Authors: Briggs Robert , Thibault Carl , Mingo Laurent 
Published: October 2018

Abstract
Due to their potential instabilities, deploying personnel onto icebergs to make direct in-situ measurement is hazardous. The preliminary results from an investigation into the usage of Unmanned Aerial Vehicles (UAV) for surveying and monitoring icebergs are presented. The project had four objectives: (i) acquisition of imagery for the generation of iceberg topside reconstructions using photogrammetry; (ii) development of a GPS tracking device and a deployment mechanism to place it onto an iceberg; (iii) development of a motion sensor to record the motion of an iceberg and a deployment mechanism to deliver it onto an iceberg; and (iv) iceberg draft measurements from a UAV-mounted ice penetrating radar.
The project has used both commercially available and custom-built UAVs. The sensor packages (cameras, tracking devices, accelerometers and ground penetrating radar) were commercial products that have been modified for this study and, when required, mountings and delivery mechanisms have been designed and manufactured to integrate the system together.
Fieldwork was performed during the 2017 iceberg season in a near-shore environment (Bonavista, Newfoundland and Labrador, Canada) aboard a survey vessel and, in 2018, from an operational supply vessel offshore Newfoundland and Labrador. The field campaigns were conducted in parallel with an iceberg profiling system that uses an integrated multibeam sonar and LiDAR system to generate composite (topside and subsurface) iceberg reconstructions. These reconstructions can be compared with the results obtained from the photogrammetry and the radar survey.
During the 2017 program, iceberg imagery for photogrammetry was acquired and GPS tracking devices were deployed onto icebergs and sea-ice. The longest iceberg track obtained was 21 days. For the 2018 campaign, further photogrammetric data was collected and ground penetrating radar surveys of icebergs were performed. The photogrammetry topside reconstructions and the draft estimates from the ground penetrating radar produced results comparable to measurements from the iceberg profiling system.
This project has explored the capability of UAVs to deliver sensor packages onto icebergs, and to take aerial measurements over and around them. They are an emerging technology that, although challenging to work with in the harsh North Atlantic environment, have proved useful.
Study on the Material Properties of Aged Steel Exposed to the Arctic Environment
Authors: Wen Feng , Bond James , Cheung T. O. , Noble Peter 
Published: October 2018

Abstract
As the oil and gas industry and international shipping companies push their assets into high latitude marine environments, it is important to thoroughly understand the performance of construction materials exposed to extremely low temperature and / or subjected to high ice loads. In the past, the design considerations have addressed the uncertainty in these areas by adopting conservative approaches. While proven effective, there exists a need for additional testing to gain insight into the safety margin levels that have been implicitly included. The work presented has the potential to lead to a better understanding of how steel materials behave in long-term Arctic conditions.
This paper presents the results of mechanical property tests of aged steel samples from the Kulluk, an ice-class rated drilling barge. This barge was exposed to the Arctic environment for almost 30 years. The Kulluk was built in Japan in 1983, specifically for exploration drilling operations in the Arctic environment. When the barge was scrapped in 2014, hull steel was selectively harvested. The intent was to conduct tests to better understand the behavior of shipbuilding steels that have endured long-term exposure to Arctic environments.
As an initial project phase, four sample groups of hull plate, from four different locations of the barge (one below the waterline, one in the ice belt region and two above the ice belt), were chosen for testing. The laboratory tests included tensile tests, Charpy impact tests and hardness tests. The test results indicate that the yield strengths, ultimate strengths, toughness and hardness of the aged steels continue to satisfy the ABS Rules requirements. A degradation assessment of these samples was also performed using these testing results and the limited data available as tracked from the barge's construction stage.
It is observed that the yield strengths and ultimate strengths remain consistent within the scatter of original or time period data. With respect to Charpy toughness values no conclusions concerning degradation can be made conclusively as the scatter in the data is substantial, especially at low temperatures. The steel in this study that has aged in the Arctic environment appears to maintain its original mechanical properties.
Based on the study presented in this paper, further studies could be performed such as additional sample tests to increase the reliability of results, material properties test for steel samples with butt/fillet welds to understand the variation of the heat affected zone (HAZ) and Crack Tip Opening Displacement (CTOD) tests to get a better understanding of the material toughness.
Use of Environmental Data to Estimate Polar Waters Operational Window
Authors: Bond J. , Oldford D. 
Published: October 2018

Abstract
The IMO Polar Code requires operators to consider the hazards associated with the specific environment of operation in Polar waters. Various sources of climate and environmental data are publicly available to quantify environmental hazards. This study considers an example Ice Class IB ship, that is not intended to operate in low air temperature (as defined in the Polar Code), and not intended to operate in marine icing conditions. Considering these hazard limitations in concert with analysis of historical data, a theoretical operational envelope for the ship is established. The methodology presented in this paper can be expanded to include more hazards as appropriate. Proposals are provided on future enhancements.
Onshore Pipeline Design and Installation Considerations for Northwestern Alaska
Authors: Eisler Ben , Murrill Mark , Walker Trent 
Published: October 2018

AbstractEver since oil potential was first discovered on the North Slope of Alaska, oil companies have been drawn to this cold region. Following the 1967 Prudhoe Bay discovery, an increased number of production pads and wells were developed and drilled. The Dalton Highway was built, paving the way for the construction of the Trans-Alaskan Pipeline System (TAPS). More wells were drilled, and large fields were developed. To date, however, development of discoveries on Alaska's North Slope have been limited to a relatively small area comprising Prudhoe Bay, the Kuparuk Area, small outliers of Badami and Point Thomson to the east, and the expanding Alpine field / Colville River area to the west. Development is just starting to extend further west into the National Petroleum Reserve Area (NPRA). The overall developed area encompasses an approximate 133 mile tract of land running east-west along the North Slope's coastal plain, of which, approximately 70 miles extend west of the TAPS pipeline. In comparison, there are approximately 260 to 300 miles between the Chukchi Sea coast and the TAPS pipeline.The majority of Alaska's North Slope area is undeveloped with almost no infrastructure. Although there are a few gravel airstrips, including the village of Atqasuk, there are no roads in between that might provide efficient access to oil prospects in Northwestern Alaska from the closest major road artery, which is the Dalton Highway.There are offshore U.S. lease blocks in the Chukchi Sea. There are also prospects at Smith Bay. One of the challenges with development of these Northwestern Alaska prospects is bringing their potential resources to market. Options include installing an onshore pipeline from the prospects to the TAPS pipeline. This paper addresses the technical aspects associated with the planning of a major pipeline across Northwestern Alaska (West of TAPS). While non-technical considerations are equally important in the planning of such a pipeline, the topical focus of this paper is to highlight the technical aspects.The ultimate goal of such a project will be to install a pipeline system. However, the project costs and routing decisions may be driven more by logistics, the environment, and the associated Right-of-Way access, as opposed to the pipeline construction itself. Furthermore, the shortest straight line route, with the least expected straight line pipe quantities, may not necessarily equate to the least costly route, design, and construction option. This will become more evident once the design aspects for such a pipeline in this area are realized and the impacts from site specific geological, geotechnical, and meteorological conditions are incorporated into the design and installation planning. Having this understanding will help better prepare an organization for permitting approvals and for adjustments once the non-technical risks and external input are considered.
Probabilistic Approach to Determine Combined Sea Ice and Wave Actions
Authors: Fuglem Mark , Thijssen Jan , Stuckey Paul , Suwan Somchat , Zhang Qianran 
Published: October 2018

Abstract
Design of offshore structures for arctic and subarctic regions requires consideration of wave, wind and ice actions. If individual actions are not mutually exclusive, then combined actions also need consideration. ISO 19906 recommends that, when possible, extreme level combined actions should be determined based on the joint probability distribution of the actions. As an alternative, ISO 19906 provides a framework where a user can determine principal and companion extreme actions independently, and sum these with calibrated combination factors applied. While the combination factors in ISO 19906 were calibrated over a range of conditions and platforms, site-specific information is not taken into account when applying the method. In this paper, a procedure is presented for determining extreme level combined actions for sea ice and waves based on site-specific sea ice and wave information, accounting for the joint probability distribution of the actions. The procedure is demonstrated for an example fixed structure on the Grand Banks off Canada's east coast. The results are compared with extreme actions determined using the ISO 19906 combination factors.
A Stationary Ocean Platform
Authors: Lee Li , Dynamics Lee 
Published: October 2018

Abstract
A new type of ocean platforms is discussed in this paper. The uniqueness of this concept is that its hull is restrained such that any of the hull motions will be resisted by the axial stiffness of moorings. As a result, the platform is essentially motionless. Because of the superb motion characteristics, it can have many applications when a stationary platform is required, such as an oil producing platform in the partially ice-locked arctic environment or a host structure for wind turbines in deeper water.
Resolving the Un-Delimited Arctic Boundary Between Canada and the United States in the Beaufort Sea by Using a Law-and-Science Approach
Authors: Bekker Pieter , van de Poll Robert 
Published: October 2018

Abstract
Fewer than half of the 500 or so potential maritime boundaries in the world have been agreed, creating uncertainty not only for the coastal States involved but also for their investors active in the offshore oil and gas industry. The complex process of agreeing and fixing boundaries or of making provisional arrangements can be time-consuming and expensive but once agreed can significantly contribute to the economic wealth of the affected countries. Disputes over maritime boundaries regularly flare up around the world and sometimes result in skirmishes. Coastal States with competing claims to maritime areas routinely offer and award oil concessions in disputed waters without the investors taking blocks being fully aware of the underlying inter-State dispute and the risks presented by an un-delimited boundary, especially one featuring straddling deposits. Indeed, maritime boundary disputes form a misunderstood and frequently overlooked area of investment risk management in the energy sector.
The Figure below shows, in red lines, the limit of the Exclusive Economic Zones ("EEZs") of the world, together with maritime boundaries delimited by treaty (depicted by blue lines) and interpreted "strict equidistance" lines in locations where no current delimited maritime boundary exists (shown in orange). The world's EEZ waters, as measured from coastlines (in black) up to the EEZ legal limit (in red), cover approximately 169,000,000 square kilometers (geodetic).