Freeman Ralph

Freeman Ralph
Memorial University of Newfoundland · Centre for Cold Ocean Resources Engineering (C-CORE)

Doctor of Engineering

About

48
Publications
3,822
Reads
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244
Citations
Citations since 2016
21 Research Items
164 Citations
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2016201720182019202020212022051015202530
2016201720182019202020212022051015202530
2016201720182019202020212022051015202530

Publications

Publications (48)
Conference Paper
The move to reduce greenhouse gas emissions in the offshore hydrocarbons production industry has resulted in a growing interest in the possibility of using offshore wind to reduce on-platform power generation. While some offshore areas are progressing towards or planning for the use of offshore wind to electrify hydrocarbon producing platforms, the...
Conference Paper
Iceberg management on the Grand Banks of Newfoundland, Canada is currently carried out without knowledge of the underwater shape of the iceberg. An iceberg profiling system is being developed to integrate the rapid generation of 3D iceberg shape data with a collection of tools that utilize the data to provide recommendations, intended to improve ic...
Article
Full-text available
Iceberg management on the Grand Banks of Newfoundland is currently carried out without knowledge of the underwater shape of the iceberg. A decision support tool (SIMS – Smart Ice Management System) is being developed to integrate the rapid generation of 3D iceberg shape data with tools that utilize the data to improve iceberg management success rat...
Article
Full-text available
In designing a floating offshore production system to operate in a region with risk of impacts from icebergs, the effectiveness of management and avoidance of detected icebergs may be considered when determining design ice loads. Management can include deflection of encroaching icebergs through towing or use of water cannon. Avoidance would typical...
Article
Full-text available
Ice loads are to be considered for any offshore development where ice is present to ensure sufficient structural capacity and global resistance. Design loads and allowable ice conditions can be specified using ice load models referenced in ISO 19906, in conjunction with a site assessment of ice and metocean conditions. Ice load models are developed...
Conference Paper
Full-text available
Iceberg drift forecasting on tactical scales remains challenging due to the lack of accurate and timely data on ocean currents, winds, iceberg geometry and mass. Current operational models are mechanistic and require a set of constants to be additionally determined for each iceberg. Alternatively, statistical methods and dead reckoning have demonst...
Conference Paper
Approaches are presented in this paper for estimating the global mooring loads and response of a semi-submersible drilling rig, as a result of pack ice loading. The focus is on loading events from pack ice conditions relevant to the Grand Banks, where the pack ice typically consists of small floes and limited concentrations. The current practice fo...
Conference Paper
Subsea oil and gas developments in the Grand Banks region, offshore Eastern Canada, require mitigation techniques to protect against iceberg keel interactions. For example, untrenched infield flowlines incorporate weak link systems designed to fail in the event of flowline snag to protect upstream and downstram assets. Even with these systems, the...
Conference Paper
During July 2018, an expedition was carried out offshore northern Newfoundland to central Labrador to profile, track, and forecast the drift of icebergs. One of the central goals of the drift modelling work was to test potential improvements in iceberg drift forecast accuracy up to 24 hours when measured iceberg profiles are used as opposed to esti...
Article
Local ice pressures are an important design consideration for vessels performing offshore stationkeeping operations, particularly in the late spring and early fall shoulder seasons when they tend to govern over global loading in the development of operating limits. This paper presents analysis of full-scale data that demonstrates the reduction in l...
Article
Structures used in Arctic regions must comply with ice-induced loading without failure, asset loss, or loss of life. Current structural design regulations, particularly for ships, rely primarily on the experience gained from first-year ice, e.g. in the Baltic Sea. Therefore, this paper presents first, the most relevant design rules for both ships a...
Conference Paper
During ship ice interaction events (i.e. rams with multi-year ice), the occurrence of local pressures vary in time and space. A link between local pressures and global forces is the sum of the local forces from n High Pressure Zones (HPZs) across the interaction face equals the total force transmitted into the structure. In this paper, a model for...
Conference Paper
Full-text available
A numerical model of ice ridge interaction with narrow sloped structure is being developed to examine possible failure scenarios and loads it may impart on the structure. In reality there is no dominant interaction scenario and the roles of the consolidated layer, keel rubble and rubble pile accumulation on the slope still remain uncertain. Bonded-...
Conference Paper
Design 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 th...
Conference Paper
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), ExxonMobi...
Conference Paper
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 confinem...
Conference Paper
In June of 2012, a 25-day field program was carried out off the east coast of Newfoundland and Labrador with the objective of obtaining high quality 3D profiles of both grounded and freely floating icebergs. The motivation for collecting the data was to provide valuable information relating to the design of offshore platforms in iceberg-prone envir...
Conference Paper
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 use...
Conference Paper
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 lo...
Conference Paper
Full-text available
Ships operating in ice-covered waters experience intense loads from ice features, particularly multiyear ice. Therefore, their structures have to be able to withstand these loads, making structural design paramount. Current formulations of ice class rules do not fully account for the probabilistic nature of ice loads, i.e. scale effects for local i...
Conference Paper
A probabilistic design method allows us to link statistical data from the operational area of the vessel with design loads providing the availability for more precise safety level assessment, which is important to ensure safe and sustainable ship transit in ice covered waters. Statistical design methods are well used for open water using spectral a...
Article
Analysis of loads from icebergs for an Arctic Floater has been performed. The determination of iceberg loads was guided by the ISO 19906 International Standard. Global and local loads on the hull, as well as mooring loads, were studied. To determine loads at the specified levels of exceedance, probabilistic methodology using Monte Carlo methods was...
Article
In offshore regions where risk of iceberg contact with subsea equipment is unacceptably high, protection options include reduction of the probability of impact by placing the equipment below the seabed in an excavation, and use of protective structures to reduce the probability of damage given an impact. An initial estimate of the probability of im...
Conference Paper
With the increased demand for hydrocarbon and mineral resources, as well as tourism, marine transportation in the arctic continues to increase. The region is harsh and fragile, making safety and environmental protection paramount. A key concern is how to estimate extreme design events that first and foremost satisfy safety and then economy. A ratio...
Conference Paper
Abstract In iceberg prone regions, subsea substructures placed on the seabed are atrisk of impacts from free-floating and scouring iceberg keels. Here themethodology for assessing iceberg loads and two mitigation strategies aredescribed. The iceberg load model was an extension of previous work forestimating iceberg impact loads on offshore surface...
Conference Paper
A simple, rectangular sub-surface caisson was evaluated using physical andnumerical modeling to develop a method for protecting subsea installationsagainst scouring keels of icebergs on the Grand Banks. This protection strategywas developed to assess the feasibility of the structure as an alternative tocostly excavations used to protect subsea equi...
Conference Paper
Oil and gas exploration activities in iceberg populated waters require careful planning to ensure operations are conducted with the utmost attention to safety and environmental protection while minimizing iceberg related downtime. This paper describes a methodology for estimating downtime and providing a tool to plan ice management fleet requiremen...
Article
Oil and gas exploration activities in iceberg populated waters require careful planning to ensure operations are conducted with the utmost attention to safety and environmental protection while minimizing iceberg related downtime. This paper describes a methodology for estimating downtime and providing a tool to plan ice management fleet requiremen...
Article
Characterization of the ice environment is an essential step in the probabilistic design approach of Arctic offshore structures. Uncertainty here could lead to overly conservative designs and higher than necessary cap-ex. Inclusion of an effective ice management strategy further mitigates risk and cost. Both tactical and historical knowledge of the...
Article
The characterization of the ice environment is a necessary step in the probabilistic design approach of Arctic offshore structures. Without such knowledge, design uncertainty is high with the result being overly conservative designs with higher build costs to deal with the uncertainty associated with sea ice and iceberg loads. In addition to knowle...
Article
Marginal field developments on the Grand Banks and other regions may not be economic if conventional protection using gloryholes must be used, and new technology is required. Identification of alternative concepts to gloryholes for protection of subsea facilities against threats from ice keel interaction was the focus of recent research and develop...
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 re...
Article
Full-text available
C-CORE and Ian Jordaan and Associates have developed a probabilistic methodology for assessing iceberg impact loads on offshore structures. The approach estimates design loads based on an annual target exceedence probability (e.g 10-4for abnormal loading events) and is consistent with ISO 19906 requirements. The model also has the capability to con...
Article
A review of the current capability within the industry is given for assessing the iceberg environment and iceberg keel / seabed structure interaction, with emphasis on operations relevant to the east coast of Canada. Consideration of calculating contact frequency and ice loads for iceberg keel impact is discussed, for both freely floating and gougi...
Article
A bergy bit impact study was conducted in June, 2001 off the northeast coast of Newfoundland. This paper documents iceberg data collected during the experiments, which include above water dimensions and underwater profiles, temperature profiles and samples of iceberg ice from the contact zone for microstructural analysis. The characteristic iceberg...
Article
This paper presents an overview of bergy bit impact trials carried out on the CCGS Terry Fox off the northern tip of the island of Newfoundland in June 18–23, 2001 and is meant to accompany the five papers that follow. The trial consisted of impacting target iceberg ice masses ranging from roughly 100 t (growlers) to 22,000 t (bergy bits) on an ins...
Article
A field test program was carried out with the CCGS Terry Fox off the northeast coast of Newfoundland in June 2001. During these trials, a total of 178 impacts occurred between the vessel and bergy bits whose sizes ranged from 20 t to 22,000 t, at ship speeds from 0.2 to 6.5 m/s.An area on the port bow was instrumented using 120 strain gauges. An in...
Article
An iceberg design load methodology has been developed to address the risk of icebergs to offshore structures. The methodology is probabilistic, accounts for the range of iceberg shapes, sizes and strengths, and environmental conditions. The model is applicable to both fixed structures such as a gravity based structure or a jackup, as well as floati...
Conference Paper
Marine operations in winter and early spring, on the East Coast of Canada, offshore Newfoundland and Labrador, are affected by the presence of sea ice and icebergs. Groups such as the Canadian Ice Service (CIS), International Ice Patrol (IIP) and PAL Environmental Services monitor and track ice movement to advise operators in the region of the risk...
Article
Marine operations in winter and early spring, on the East Coast of Canada, offshore Newfoundland and Labrador, are affected by the presence of sea ice and icebergs. Groups such as the Canadian Ice Service (CIS), International Ice Patrol (IIP) and PAL Environmental Services monitor and track ice movement to advise operators in the region of the risk...
Conference Paper
The design of offshore structures for ice loads requires estimates of global ice forces and local ice pressures on the structure. The focus is ice crushing against a structure, for example icebergs impacting an offshore rig. To determine these, the global interaction area and local design area are precisely defined. A rational basis for defining th...
Article
Over the 2002-2004 ice seasons there has been an increase in the number of ice island sightings in the North Atlantic, investigations are currently being conducted to establish if these sightings are an anomaly or part of a more permanent trend. Ice Islands are of particular interest to offshore oil and gas operations on the Grand Banks. Their larg...
Article
Full-text available
This paper presents and overview of bergy bit impact trials carried out on the CCGS Terry Fox off the northern tip of the island of Newfoundland in June 18-23, 2001. The trial consisted of impacting target iceberg ice masses ranging from roughly 30 t (growlers) to 22,000 t (bergy bits) on an instrumented bow area of the 'Terry Fox' at various forwa...

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