Numerical modelling of ice growth, melt and transport on regional scales such as coastal seas, estuaries, rivers or lakes can provide crucial input for safe and efficient designs and installations of marine infrastructure in arctic, sub-arctic or mid-latitude regions. The modelling of ice and related complex physical processes on these regional scales is however still rather unexplored.
The complexity of ice modelling on local and regional scales is best illustrated in areas where ice-covered sea water is mixed with fresh river water and a thermal discharge from for instance a refinery or power plant. Such a situation exists in the Svartbackfjarden, an estuary some 35 km to the east of Helsinki, Finland. Two minor rivers discharge into this estuary. The estuary freezes during the winter with ice thicknesses typically in the range of 20 to 50 cm. In this estuary an oil refinery takes in cooling water at a depth of about 15 m. The heated water is discharged at the surface and results in melting of the sea ice in the vicinity of the outfall. However, given the fresh water from the rivers in the early spring, and the fact that the salinity of the intake water is higher than the surface water, the discharged cooling water has been observed to flow under the relatively cold fresh layer just under the ice. Due to mixing of the plume with the surrounding water, the temperature of the fresh water layer increases, leading to melting of the ice at some distance from the plant's outfall.
This paper presents a case study with Delft3D, which is a flexible integrated numerical modelling programme that enables simulation of 3-dimensional flow, sediment transport, morphology, waves, spills, water quality and ecology, in combination with a recently developed ice module. The 3-dimensional modelling with Delft3D of the thermal discharge from the oil refinery in the ice-covered Svartbackfjarden estuary is presented and compared to local observations of currents, water temperature, salinity and ice thickness. The case study will show the capability of Delft3D to cover all the relevant physical processes that determine the temporal and spatial characteristics of the ice and the thermal discharge, under influence of fresh river discharges, hydrodynamic, meteorological and atmospheric forcing.
These capabilities will contribute to the further development of integrated ice modelling on regional scales, eventually benefiting the sustainability, efficiency and safety of the designs of marine structures in ice-covered waters.
The Arctic is the frontier area to securing energy supplies for the future. Finding oil and gas in the Arctic and subarctic regions is in itself challenging. Extracting the hydrocarbons in a safe and economical way, is considered possibly even more challenging due to extreme low temperatures, ice conditions, remoteness and a sensitive natural environment. The paper is based on ongoing development of a subsea separation and storage system for application in deepwater arctic. The paper describes solutions on how deepwater subsea separation of hydrocarbons and storage of oil can be achieved in hostile environments enabling close to continuous production also when surface production facilities has to abandon location. Overall arctic field development suggestions are presented based on the solutions.
The International Energy Agency predicts world energy needs in coming decades will still include significant contributions from oil and gas. The Arctic represents a highly prospective region where technology enables future exploration and production. This paper examines select challenges the oil and gas industry (Industry) faces in the Arctic and considers collaboration and cooperative efforts that will continue to mitigate these issues.
Aspects of Arctic oil and gas exploration that present the greatest opportunities for cooperation include baseline studies, engineering, and oil spill prevention, detection, and response. Sharing physical and technical resources can augment limited Arctic infrastructure, ship availability, and potentially widen restrictive operating windows. Collaborations from baseline science monitoring, ice modeling, and oil spill response consortiums improve efficiency while decreasing costs for industry, consumers, and governmental agencies.
The United States of America (U.S.) assumes Arctic Council Chairmanship from 2015 to 2017 and is expected to continue fostering regulatory collaboration. The U.S. issued its approach to Arctic policy in the 2013
Many Arctic-interest groups aim to outline research and technology pursuits that support exploration and development in the Arctic. Navigating numerous stakeholder interests and incentives presents challenges. However, it is essential and the responsible action in order to advance resource access and development.
Oil producing companies have partnered in offshore oil exploration since the 1930s - collaborating on vessels and other support materials. Early overall collaboration and competence-sharing are some of the techniques that can optimize efficiency for all.
Offshore exploration and production in the Arctic is moving forward in a stepwise approach. Years of research and experience are preparing the world for continued prudent development of resources in the Arctic region. Operational limitations make collaboration and knowledge-sharing vital to the economics of offshore exploration.
Tcheverda, V.A. (Institute of Petroleum Geology and Geophysics SB RAS) | Khaidukov, V.G. (Institute of Petroleum Geology and Geophysics SB RAS) | Lisitsa, V.V. (Institute of Petroleum Geology and Geophysics SB RAS) | Reshetova, G.V. (Institute of Computational Mathematics and Mathematical Geophysics SB RAS)
Seismic study of transition zones in Arctic regions in summer is troublesome because of the presence of large areas covered by shallow waters like bays, lakes, rivers, their estuaries and so on. The winter is more convenient and essentially facilitates logistic operations and implementation of seismic acquisition. But in winter there is a complicating factor - intensive seismic noise generated for acquisitions installed on the ice covering shallow waters. It is well-known that this noise is connected with flexural waves generated in ice by seismic sources. These waves are one of the strongest known coherent noises. At the same time they are much slower than surface waves well known for onshore acquisition and seem to be easy avoided by f-k filtration. However, this type of filtration fails to suppress such noise. To understand the matter the representative series of numerical experiments are conducted and prove that the main impact to noise is multiple conversions of flexural waves to the body ones and vice versa. Ways to reduce this noise are proposed and discussed.
Metrikin, Ivan (Statoil ASA) | Teigen, Sigurd Henrik (Statoil ASA) | Gürtner, Arne (Statoil ASA) | Uthaug, Eirik Strøm (Statoil ASA) | Sapelnikov, Dmitry (Multiconsult AS) | Ervik, Åse (Multiconsult AS) | Fredriksen, Arnt (Multiconsult AS) | Lundamo, Trine (Multiconsult AS) | Bonnemaire, Basile (Multiconsult AS)
This paper presents a performance evaluation method of a floating, geo-stationary structure in sea ice. Using a turret-moored drillship as an example, the paper explains an approach to efficiently combine model-scale experiments and numerical simulations to analyze ice-structure interactions. A novel numerical simulation tool - Statoil's SIBIS model - is used to investigate the performance of the drillship concept in various design ice conditions. The presented method allows cost-efficient performance evaluations of ice-capable platforms throughout the early-phase design process, and leads to increased safety and commerciality of exploration operations in the Arctic.
Permafrost in Arctic is one of the most important factors when exploration and production of gas and gas condensate fields due to its sensitivity to any technogenic (humane-made) impact or climatic change. Exploration and production procedures in the areas with instable permafrost cause such processes like thermokarst, thermoerosion, flooding, frost heave, surface subsidence, shallow gas blowouts et al. These processes require their forecast and prevention when gas field development designing. However permafrost sometimes is very different in its properties even within area of one production well cluster, so careful study of permafrost behavior is needed before and during gas production. Russian experience of gas field development at complicated permafrost (geocryologic) conditions of Yamal peninsula (Kara Sea shore) is presented.
The Yamal LNG Project in Russia involves a number of challenges; besides those of building a liquefaction plant in the Arctic Circle, along with a port accessible all year round for exporting the LNG production, the very issue of marine export - to ensure safe and reliable transportation at optimized costs - hinges on the development of Arctic LNG Carriers capable of breaking ice themselves with no assistance from ice-breakers. This paper addresses some of the preliminary steps and the stages of development of the final solution: the Arctic ice-breaking LNG Carrier.
The Hoop area in the Barents Sea (Norway) is a frontier province with limited well control. It was initially regarded as a gas-dominant hydrocarbon province, but explorationists are viewing the area with new interest after the successful Wisting oil discovery. Despite this success, the area is considered high-risk due to inefficient sealing, and the apparent absence of high-quality reservoir sands. This paper demonstrates how the integration of 3D seismic and 3D controlled source electromagnetic (CSEM) data can help de-risk these uncertainties and generate new play models. The study suggests that such an integration can be avaluable workflow component for the 23rd application round in the area, and for drill-drop licence decisions.
This paper presents a compendium of applications for thermosyphon type passive refrigeration devices for onshore facilities in the arctic. It's very seldom that thaw-stable permafrost or rock is available to found structures on and facilities need to be located on permafrost that is not thaw-stable. There is a long history of thaw subsidence and differential settlement when facilities on thaw unstable permafrost are not thermally stabilized.
Thermosyphons are the most widely used passive refrigeration devices and have been used since 1960 to provide thermal stability to foundations constructed on permafrost. In the arctic oil patch, thermosyphons have been used since the 1970’s with the largest single application being on the vertical support members for the Trans Alaska Pipeline that traverses Alaska. Early thermosyphon devices were installed vertically, and then in 1978, thermosyphons were first used for subgrade cooling beneath a structure with a slab-on-grade over ice-rich permafrost. In the 1980’s, thermosyphons were used to passively refrigerate the ground beneath heated tanks built on-grade negating the need for active refrigeration systems. In the 1990’s, the loop-type evaporator was developed for thermosyphons and the effective run of the evaporator beneath structures tripled. In the 2000’s, thermosyphons began to be used to solve problems around wellheads where hot oil was brought up through permafrost. Today, thermosyphons have a myriad of applications around the arctic oilfield and many of those are presented herein. Thermosyphons are not suited for all refrigeration applications in the arctic and some limitations are detailed.
As the demand for energy resources continues to grow, the oil and gas industry is looking north to the Arctic for discovery and extraction of offshore hydrocarbon resources. In seasonal ice covered waters and regions frequented by icebergs where ice loads are significant; the Gravity Based Structure (GBS) has been shown, in cases, to be the preferred technically feasible solution (e.g. Hibernia, Hebron, Sakhalin 1, and Sakhalin 2). In remote locations, where there may be no pipeline infrastructure or the cost of such infrastructure may be too high, the GBS can be designed to offer storage at a reasonable cost. In some circumstances, a ballasted steel structure might have advantages over traditional steel reinforced concrete structures, as outlined in this paper.
In these areas where ice loads are significant, the majority of installed Gravity Based Structures are comprised of steel reinforced concrete. This paper presents the concept of a steel GBS with a storage option for remote Arctic regions. The proposed structural design of the steel GBS is based on the study of ice loads and associated stability. The sizing, advantages and limitations of the unique hull structure are discussed in this paper. The paper discusses about the design and construction of a steel hull GBS capable of withstanding both first year ice and multi-year ice loads in an Arctic setting, where there is future proposed route for ice-class shuttle tankers. For the purpose of this paper, water depths between 30m and 50m are considered for the design of the structure. Optimized sizing of the GBS for various water depths, in order to achieve an approximate storage of six to eight days of crude oil production, is discussed.