Jung Chan Choi

Jung Chan Choi
Norwegian Geotechnical Institute | NGI · Department of petroleum geomechanics and geophysics

PhD

About

51
Publications
5,787
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567
Citations

Publications

Publications (51)
Conference Paper
The road and railways infrastructure developments in Norway have increased the interest in the geotechnical challenges associated with slope stability under freezing-thawing cycles. In this case study, a critical slope was identified in a cold region based on field site investigation and frost-heave laboratory tests, and a series of numerical simul...
Article
Full-text available
This paper presents recent innovations implemented in the LaRiMiT (Landslide Risk Mitigation Toolbox) webtool. These include an innovative methodology for utilising experts’ scoring of landslide risk mitigation measures directly within the decision support tool, and updating of the tool’s database over structural measures to include many nature-bas...
Article
Full-text available
Although geological CO2 sequestration is an essential solution for reducing anthropogenic carbon dioxide from the atmosphere, the method needs critical evaluation of injection-induced mechanical risks for safe and reliable CO2 storage. 3D field-scale geomechanical modeling is a preeminent solution for assessing mechanical risks of subsurface geolog...
Article
The aim of the current study, IGCCS (2017–2020), is to evaluate the feasibility of micro-seismic (MS) monitoring of CO2 injection into representative storage candidates in the North Sea, based on broad and quantitative characterization of relevant subsurface behavior with respect to geology, geomechanics and seismicity. For this purpose, we first g...
Conference Paper
CO2 injection into a saline aquifer requires a viable caprock to arrest the vertical movement of the CO2 plume. Quantitative assessment of caprock integrity is often challenging because of uncertainties involved in the model input parameters. In this study, Draupne Formation's reliability as caprock is evaluated before CO2 injection by introducing...
Technical Report
Full-text available
The technical report is a summary of RCN CLIMIT-KPN project, titled "Induced-seismicity geomechanics for controlled CO2 storage in the North Sea (IGCCS)". The whole report will be available upon request via ResearchGate or via jp@ngi.no.
Article
CO2 injection into a saline aquifer requires a viable caprock to arrest the vertical movement of the CO2 plume. Quantitative assessment of caprock integrity is often challenging because of uncertainties involved in the model input parameters. In this study, Draupne Formation's reliability as caprock is evaluated before CO2 injection by introducing...
Article
Full-text available
The mechanical integrity of caprocks overlying injection formations is one of the key factors for safe storage of carbon dioxide in geological formations. Undrained effects caused by CO2 injection on strength and elastic parameters should be properly considered in the operational design to avoid fracture creation, fault reactivation and unwanted su...
Article
Full-text available
Leak-off pressure (LOP) is a key parameter to determine the allowable weight of drilling mud in a well and the in situ horizontal stress. The LOP test is run in situ and is frequently used by the petroleum industry. If the well pressure exceeds the LOP, wellbore instability may occur, with hydraulic fracturing and large mud losses in the formation....
Article
Full-text available
Reliable assessment of fault stability is key for safe CO2 storage in a saline aquifer in fault-bounded structures. The Alpha structure located in the Vette fault's footwall in the Smeaheia area, offshore Norway, is one of the potential CO2 storage sites with a fault-bounded three-way closure. Assessing fault stability in the Smeaheia area is chall...
Article
Full-text available
Large-scale geological carbon storage in the North Sea will involve injecting CO2 in a super-critical state into deep saline aquifers. As CO2 is injected, stress changes due to fluid pressure and temperature changes may result in deformation and potentially may result in microseismicity if existing faults are reactivated. Microseismicity may provid...
Article
In this study (IGCCS), we evaluate the feasibility of micro-seismic (MS) monitoring of CO2 injection into storage candidates in the North Sea to ensure safe operations. MS monitoring relies on measuring seismic signals resulting from abrupt subsurface movements such as the (re)-activation of faults and fractures. To be successful, MS monitoring tec...
Conference Paper
This study focuses on the geomechanical and Acoustic Emission response of caprock lithologies in the North Sea CO2 storage sites. Two multistage triaxial tests perform on caprock lithologies. One shallow (700 m) mudstone/shale from Nordland Group, Southern Viking Graben and another one deeply buried (2581 m) Draupne shale from well 16/8-3S from the...
Article
Full-text available
Fractures and faults are critical elements affecting the geomechanical integrity of CO2 storage sites. In particular, the slip of fractures and faults may affect reservoir integrity and increase potential for breach, may be monitored via the resulting seismicity. This paper presents an experimental study on shale samples from Draupne and Rurikfjell...
Article
Full-text available
Recently, the road and railways infrastructure developments in Norway have led to renewed interests on the geotechnical challenges associated with slope stability under freezing-thawing cycles. Despite the amount of research available on the topic, there are few comprehensive studies involving laboratory testing, numerical analysis, and field monit...
Article
Landslides represent major threats to life and property in many areas of the world, such as the landslides in the Three Gorges Dam area in mainland China. To better prepare for landslides in this area, we explored how several machine learning algorithms (long short term memory (LSTM), random forest (RF), and gated recurrent unit (GRU)) might predic...
Article
This paper presents results of the direct shear tests on pre-fractured specimens from Rurikfjellet Formation, Svalbard, Arctic Norway. It also evaluates the risk of shear failure along pre-existing fractures due to possible over pressure. Rurikfjellet Formation is composed of clay-rich shale and is part of the cap rock for the proposed CO2 storage...
Conference Paper
Full-text available
Carbon capture and storage is necessary if we are to reach net-zero global CO2 emissions. Currently, North Sea saline aquifers are targets for large-scale geological storage of CO2. At such storage sites, geophysical monitoring is needed to follow chan-ges within the reservoir sandstone and the sealing caprock above and avoid leakage of CO2 to the...
Conference Paper
Full-text available
Norway is planning to launch large-scale CO2 storage projects in the North Sea. The first full-scale project "Northern Lights" is on its way to realization, where Equinor is teaming up with Total and Shell. For such offshore CO2 storage projects, geomechanical and geophysical evaluations are essential to ensure safe operation and avoid unwanted lea...
Article
Full-text available
Monitoring microseismic activity provides a window through which to observe reservoir deformation during hydrocarbon and geothermal energy production, or CO2 injection and storage. Specifically, microseismic monitoring may help constrain geomechanical models through an improved understanding of the location and geometry of faults, and the stress co...
Article
This paper focusses on hot underground tunnels and studies the effect of ground source heat pump (GSHP) intermittent operation and changing tunnel air temperature profile on energy tunnel thermal efficiency. The effects of heat pump operation on the tunnel surrounding soil and the soil recovery rate when the heat pump is not in operation were also...
Conference Paper
There are a lot of reports of formation induced damage of wells world-wide. Despite extensive literature on the subject, formation induced damage is not a standardized part of well design. One reason may be that the associated fundamental mechanism is not yet fully understood, which makes it difficult to implement in design rules. As a step towards...
Conference Paper
Leak-off pressure (LOP) is an important parameter to determine a weight of drilling mud and in-situ horizontal stresses. When the well pressure become higher than the LOP, it can cause a wellbore instability during drilling, such as a mud loss. Thus, accurate prediction of LOP is important for safe and economical drilling for the oil and gas indust...
Conference Paper
Full-text available
We monitored acoustic emissions during the mechanical testing of materials relevant to potential North Sea geological CO2 storage sites. We measured the mechanical properties of the materials and characterised the observed failure mechanisms, to better understand the potential for microseismicity within these lithologies due to CO2 injection.
Article
Methane production from gas hydrate reservoirs is only economically viable for hydrate reservoirs in permeable sediments. The most suitable known prospect in European waters is the paleo Danube deep-sea fan in the Bulgarian exclusive economic zone in the Black Sea where a gas hydrate reservoir is found 60 m below the seafloor in water depths of abo...
Article
This paper presents Class A and Class C predictions illustrating the variability of predicted settlement, horizontal displacement and pore pressure under the Australian Research Council Centre of Excellence for Geotechnical Science and Engineering (CGSE) Ballina test embankment. Probabilistic methods were combined with the finite element program Pl...
Article
Gas hydrate dissociation is often considered as a precursor or triggering factor for submarine slope failures occurring in relatively deep waters where the bulk of the gas hydrate is found in fine-grained sediments. However, there are actually relatively few studies that focus on the effect of gas hydrate dissociation on the behavior of clays, and...
Conference Paper
Full-text available
Our numerical study shows that the resistivity measured using radial two-electronodes setup could capture the material anisotropy with properly estimated geometry factors. The results indicate that the suggested system, which has two small electronodes, could be a simple and efficient technique to measure the anisotropy of sample together with acou...
Chapter
Risk and probabilistic analyses have now had enough applications that make them effective to use in practice. The approach provides more insight than deterministic analyses alone. They help reduce uncertainty and focus on safety and cost-effectiveness. The paper illustrates the use of reliability methods for the analysis of slopes in sensitive clay...
Conference Paper
The mitigation of landslide risk to human-valued physical and non-physical assets is a fundamental component in the disaster risk management cycleOpen image in new window. The reduction of risk can be pursued through the selection, planning and implementation of suitable mitigation measures and/or actions. The selection of the most appropriate miti...
Article
Full-text available
The thermal conductivity of soils is an important property in energy-related geotechnical structures, such as underground heat pumps and underground electric power cable tunnels. This study explores the effects of geotechnical engineering properties on the thermal conductivity of soils. The thermal conductivities of quartz sands and Korean weathere...
Article
Full-text available
The thermal needle probe method, which is widely used for measuring the thermal conductivity λ of soils, deploys a long and thin metallic probe that houses a line heater and a temperature sensor. However, inserting such probes into consolidated or densely compacted soils or rocks is difficult, frequently causing buckling of the probe and severe dis...
Conference Paper
This study presents results of a laboratory direct shear test program on shale samples from cap rock of the Longyearbyen CO2 storage pilot on Svalbard, Northern Norway. The objective is to determine frictional properties of fractured shale samples which are key elements in determining the maximum pressure a cap rock can sustain. Shale samples were...
Conference Paper
This study assesses the characteristic of flow barriers observed from 4D time-lapse survey for CO2 storage in Tubaen Formation, Snohvit field by geomechanical analysis. The flow barriers are hypothesized as structural compartments (e.g. sub-seismic faults) and then the stability of faults are assessed by both numerical and analytical approaches. Th...
Conference Paper
Full-text available
We introduce a novel approach to measure directly the formation pore pressure and temperature during injection and production operations. We analyze a set of acquired data and compare with conventional injection operation data. Through a system identification algorithm, we process the raw data and remove noise from the data. The overall result show...
Conference Paper
We introduce a novel approach to measure directly the formation pore pressure and temperature during injection and production operations. We analyze a set of acquired data and compare with conventional injection operation data. Through a system identification algorithm, we process the raw data and remove noise from the data. The overall result show...
Article
This study is to analyze pore pressure data acquired with a novel measurement system that is installed for a pilot test just outside a cased well within a sand formation in the North Sea. The system uses a wireless communication through casing to transfer measured data from well outside to inside. Long-term trend in the measured pore pressure is co...
Article
The effects of both direction and rate of groundwater flow on the performance of various types of borehole heat exchanger (BHE) arrays are examined using a two-dimensional coupled heat conduction–advection model. The heating operations were simulated over a period of 15 yrs using three types of arrays: rectangular, L-type, and single line. The resu...
Article
This paper presents an experimental and numerical study on evaluation of thermal response and performance of prototype precast-high strength concrete (PHC) energy pile. Short-term field thermal response tests (TRTs) were conducted for the PHC energy piles installed in partially saturated weathered granite soil deposit, in which two types of heat ex...
Article
The effect of varying the thermal properties of inhomogeneous unsaturated soil on the intermittent operation of a vertical ground heat exchanger (GHE) was simulated by a conjugate heat transfer simulation using a transient conductive heat transfer model. A three-phase soil model was used to introduce soil properties that vary with depth. The perfor...
Article
A reliability-based slope stability assessment method considering fluctuations in the monitored matric suction was proposed for real-time identification of slope risk. The assessment model was based on the limit equilibrium model for infinite slope failure. The first-order reliability method (FORM) was adopted to calculate the probability of slope...
Article
Many slope failures are induced by rainfall infiltration. A lot of recent researches are therefore focused on rainfall-induced slope instability and the rainfall infiltration is recognized as the important triggering factor. The rainfall infiltrates into the soil slope and makes the matric suction lost in the slope and even the positive pore water...

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Project (1)
Project
Norway plans to launch large-scale CO2 geological storage projects in the North Sea. For such offshore projects, geophysical monitoring is essential to ensure safe operation, and avoid leakage of CO2 to the seabed. In IGCCS, we evaluate the feasibility of microseismic monitoring at candidate North Sea injection sites, through combined laboratory study and field-scale modelling.