Luke Griffiths

Luke Griffiths
Norwegian Geotechnical Institute | NGI · Integrated Geotechnology

PhD
Geoscientist working on subsurface characterisation for deep and shallow applications.

About

26
Publications
9,534
Reads
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368
Citations
Additional affiliations
March 2020 - present
Norwegian Geotechnical Institute
Position
  • Engineer
Description
  • Member of the Integrated Geotechnology section, for shallow to deep subsurface characterisation.
March 2018 - February 2020
Norwegian Geotechnical Institute
Position
  • PostDoc Position
Description
  • Within CLIMIT project IGCCS (Induced-seismicity Geomechanics for Controlled CO2 Storage in the North Sea), I acquired and analysed laboratory microseismic data, and characterised the mechanical properties North Sea reservoir and cap rocks.
Education
January 2015 - February 2018
University of Strasbourg
Field of study
  • Geophysics
September 2011 - December 2014
EOST
Field of study
  • Geophysics

Publications

Publications (26)
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
Full-text available
The geometry of voids in porous rock fall between two end-members: very low aspect ratio (the ratio of the minor to the major axis) microcracks and perfectly spherical pores with an aspect ratio of unity. Although the effect of these end-member geometries on the mechanical behaviour of porous rock has received considerable attention, our understand...
Article
Full-text available
Microcracks can affect the mechanical properties of rocks, such as their stiffness and strength. To provide a link between the microstructural parameters and the mechanical behaviour of rock, micromechanical models use parameters that represent a quantitative description of the microcrack population. However, these parameters are difficult to const...
Article
Full-text available
To monitor both the permanent (thermal microcracking) and the non-permanent (thermo-elastic) effects of temperature on Westerly Granite, we combine acoustic emission (AE) monitoring and ultrasonic velocity measurements at ambient pressure during three heating and cooling cycles to a maximum temperature of 450 °C. For the velocity measurements we us...
Conference Paper
Full-text available
During hydrocarbon production variations in fluid saturation and pressure cause density and wave velocity changes, resulting in reflectivity amplitude and travel-time changes (Calvert, 2005). Where multiple surveys have been acquired over a producing reservoir these changes manifest themselves as differences in the seismic response between surveys....
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...
Article
The tensile strength of volcanic rock exerts control over several key volcanic processes, including fragmentation and magma chamber rupture. Despite its importance, there is a paucity of laboratory data for the tensile strength of volcanic rocks, leading to an incomplete understanding of the influence of microstructural parameters, such as pore siz...
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
Full-text available
More sustainable and environmentally friendly concretes are essential to reduce the climatic and environmental impact of the growing demand for concrete to fuel urban sprawl. This manuscript reports on an experimental study designed to test the fire resistance of one such concrete, prepared to contain natural zeolite-bearing tuff. The fire resistan...
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
The Norwegian Continental Shelf is an emerging host for full-scale carbon capture and storage (CCS). To ensure safe operation and reservoir storage conformance, CCS requires accurate evaluation of the geomechanical response of reservoir and cap rocks to CO2 injection. During injection of CO2, increasing pore pressure and decreasing temperature lead...
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
Every year, the European Geosciences Union (EGU) brings together experts from all over the world at its General Assembly, covering all disciplines of the Earth, planetary and space sciences. The EGU Division on Energy, Resources and the Environment (ERE) is concerned with one of the humankind's most challenging goals – providing affordable, reliabl...
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...
Conference Paper
Measurement, monitoring and verification (MMV) are vital to ensure the conformance and containment of geological carbon storage (GCS). This requires cost-efficient and multidisciplinary approaches. To investigate this challenge in an offshore environment, we have studied and tested different monitoring approaches, covering seismic, electromagnetic,...
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
Full-text available
Abstract Coda wave interferometry (CWI) is a high-resolution technique that aims at tracking small changes in a diffusive medium from the time correlation of seismic waveforms. CWI has been widely used in recent years to monitor the fine-scale evolution of fault zones and more recently of deep reservoirs. However, to provide a quantitative interpre...
Article
Full-text available
Every year, the European Geosciences Union (EGU) brings together experts from all over the world at its General Assembly, covering all disciplines of the Earth, planetary and space sciences. The EGU Division on Energy, Resources and the Environment (ERE) is concerned with one of the humankind's most challenging goals – providing affordable, reliabl...
Article
Full-text available
The use of Mt. Epomeo Green Tuff (MEGT) as a building stone is widespread on Ischia Island (Italy). We assess here the fire resistance of MEGT by thermally stressing samples to temperatures up to 1000 °C. Porosity and uniaxial compressive strength increase and decrease from 44% and 4.5 MPa at ambient temperature to 48% and 1.5MPa following exposure...
Thesis
Lorsqu'elle est chauffée, la roche peut subir une microfissuration thermique, qui influence ses propriétés physiques, mécaniques, thermiques, et de transport. La surveillance de la microfissuration thermique en laboratoire a été principalement réalisée pendant le chauffage, et rarement lors du refroidissement ou du chauffage cyclique que la roche s...
Data
Description of the image processing algorithm to extract cracks or thin lines from 2D images, as presented in "Quantification of microcrack characteristics and implications for stiffness and strength of granite", Griffiths et al. (2017).

Questions

Question (1)
Question
Is it possible to infer the background stress tensor from the moment tensors of tensile earthquakes, which have a significant non double-couple part?
Can I apply techniques used for stress inversion of pure double-couple moment tensors to the double-couple part of my moment tensors? (i.e. using methods which assume the slip vector is within the fault plane, for example Michael (1984) method and variants of.)
If none of the above: what/how can I learn about regional stress conditions from such data?

Network

Cited By

Projects

Projects (6)
Project
The goal of the project is to use very small (mm scale) ground surface deformation to monitor and manage subsurface. For this we will: • Demonstrate the ability for continuous and accurate monitoring of surface deformation using satellite data, pressure sensors and fiber optic technology • Develop geomechanical models for characterization of subsurface stress distribution, anisotropy and permeability calibrated by the detected surface movements • Develop innovative interpretation algorithms and inversion workflows, for data integration and cost-efficient data processing • Optimize sampling array configuration of ocean bottom sensors for cost efficiency, detectability and long-term safety assurance.
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.