Norwegian Geotechnical Institute (NGI) Digital Archive
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Annual Report 2020
Get PDFDuring the first year of the project period 2020-2022 of NGIs research project on Snow avalanches, Applied Avalanche Research in Norway (AARN), work was conducted in all three work packages (WP 1 – Avalanche formation and release, WP 2 – Avalanche dynamics, WP 3 – Avalanche interaction) and several cross-package topics. In addition, several significant upgrades were made to the research infrastructure at Fonnbu and Ryggfonn. During 2020, the results of the research activities have been published in peer-reviewed journals, summarised in technical notes, and presented online at national and international conferences and seminars. AARN personnel have been actively engaged in educational outreach activities, including as lecturers and student supervisors.NVE (Norges vassdrags- og energidirektorat
Physical modelling of pile drilling in sand
Get PDFDrilling for foundation piles and tieback anchors through soils using a continuous casing to support the borehole is often referred to as "overburden drilling". Monitoring data from several case studies show that overburden drilling may cause considerable short-term ground settlements indicating a loss of soil volume around the casings. However, further insight is required to understand the mechanisms that govern overburden drilling. Novel physical model tests were carried out to investigate the effects of varying parameters such as flushing media (water or air), flow and penetration rate on the penetration force, pore pressure changes, soil displacements and drill cutting transport. Tests with water flushing indicate a clear relation between the flow and penetration rate and the resulting influence on the surrounding ground. Increasing flow rates caused larger excess pore pressures at greater radial distances and generated more excess drill cuttings compared to the theoretical casing volume. The obtained results were translated into a non-dimensional framework to estimate optimal flushing parameters in similar conditions. The air flushing tests were considerably limited by the modelling constraints. Notable reduction of pore pressures adjacent to the casing indicate an air-lift pump effect that can lead to extensive ground movements as observed in the field.publishedVersio
Risk assessment of terrestrial transportation infrastructures exposed to extreme events
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Impact of innovations from the Norwegian CCS Research Centre - NCCS
Get PDFWe have evaluated the potential impact of the research and innovation performed in the Norwegian CCS Research Centre (NCCS). In this context, impact was evaluated along several axes. Examples include reduced emissions, economic impact (increased value creation, saved cost), improved decision making, saved energy, and industrial potential. The reference system is the envisaged CCS network in Europe by 2030. The study illustrates how the research and expected innovations can impact CCS chains and society when applied. Keywords: CCS, innovations, impactpublishedVersionpublishedVersio
Characteristics of cyclic undrained model SANISAND-MSu and their effects on response of monopiles for offshore wind structures
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CSEM for CO2 Storage – Feasibility Study at Smeaheia to Optimise Acquisition
Get PDFIn this work, we evaluate the use of controlled-source electromagnetics (CSEM) for CO2 monitoring at Smeaheia, a possible candidate for future phases of the Norwegian full-scale CCS project. CSEM is sensitive to electrically resistive material replacing conductive pore water in the pore space, which enables to infer volumetric estimates of the injected CO2 in the formation. CSEM is often used in combination with high-resolution seismic reflection data due to the sensitivity of the two methods to complementary physical properties. Here, we present a technique to optimise the CSEM survey parameters for efficient 4D surveying. Realistic synthetic models prior to and after injection are derived from reservoir modelling and converted to electrical resistivities. Inversion tests are carried out in 2D for the baseline and monitor cases considering realistic data errors. We show that the resistivity changes due to CO2 injection can be monitored using CSEM. We discuss the optimal orientation of the receivers, frequency range and transmitter-receiver offset. We finally discuss a strategy for optimal survey design based on the sensitivity to the CO2 plume.publishedVersio
Transport infrastructure and geotechnical engineering: ELGIP position paper
Get PDFThe European Large Geotechnical Institutes Platform (ELGIP) is a group of 14 European research organizations, leading in geotechnical engineering, which aims to promote internationally the profession, its network and its societal relevance. One ELGIP vision is that all transport infrastructure should aim for an optimal geotechnical design. The present paper shows the relationship between the pressing challenges on European transport infrastructures and the crucial role that geotechnical engineering plays in solving them, emphasising the need for improved knowledge and understanding of ground properties in transport infrastructure.publishedVersio
Climate Change Adaptation of Geo-Structures in Europe: Emerging Issues and Future Steps
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Estimation of Thickness and Layering of Johansen and Cook Sandstones at the Potential Co2 Storage Site Aurora
Get PDFWe have estimated the reservoir sand thickness and internal layering in the Aurora area, a planned geological CO2 storage site in the northern North Sea. The results are obtained by stochastic Markov chain Monte Carlo (MCMC) simulations on probabilistic lithology and fluid distributions in the subsurface. The probabilistic distributions are obtained by inverting the seismic data in a Bayesian framework. The inversion is using angle-dependent pre-stack seismic data and the linearized seismic forward model of Aki and Richards to estimate the posterior probabilities of lithology and fluid classes (facies) in the subsurface. The facies are defined from well log data by identifying depth intervals with distinct elastic responses to seismic waves. The inversion methodology and the MCMC simulations are developed and implemented by the Norwegian Computing Center. The planned CO2 storage reservoir comprises the Johansen and Cook sandstones belonging to the Early Jurassic Dunlin Group. The injection site (well 31/5-7) is located south and west of the Troll field in the northern North Sea and is currently being developed by Equinor in partnership with Total and Shell as part of the Northern Light project. The seismic inversion is mapping structural details like faults and internal layering of the sandstones, and the MCMC simulations estimate the probability of sand thickness and expected layering. Results show that the Johansen Formation sandstone has a tendency of layering towards the west and largest thickness to the east in the inversion area. The sandstone in the Cook Formation is generally thinner, and probability maps indicate that it pinches out to the east. Cumulative thickness distributions provide low (P90), median (P50), and high (P10) thickness maps of both Johansen and Cook Formation sandstones. The presented methodology defines a functional workflow for quantifying the thickness uncertainty and possibly internal layering of the reservoir sands. Such results may provide important input for future field development strategies and CO2 migration predictions.publishedVersio
