Energy, Resources and the Environment

Early Career Scientists

Change to Early Career Scientist definition

Change to Early Career Scientist definition

Earlier this year the term Young Scientist (YS) was replaced by Early Career Scientist. Now, in a positive move, the EGU Council has approved a change to the definition of an ECS.

Previously the definition of an ECS was:

A scientist who is 35 years old* or younger, AND who can be an undergraduate or postgraduate (Masters/PhD) student or who has received his or her highest degree (e.g., BSc, MSc, PhD) within the past seven years*.
* Where appropriate, up to one year of parental leave time may be added per child.

However, feedback from early career scientists at the 2014 and 2015 Young Scientists Forums, supported by the findings of the Young Scientist Survey of 2014, highlighted that ECS benefits are important at the onset of an academic career, independent of the age of the recipient. Taking into account this view, the EGU Council has approved a new definition which is inclusive of those who start their research career later on in life.

The new definition reads as follows:

An Early Career Scientist (ECS) is an undergraduate or postgraduate (Masters/PhD) student or a scientist who has received his or her highest degree (BSc, MSc, or PhD) within the past seven years*.
* Provided parental leave fell into that period, up to one year of parental leave time may be added per child, where appropriate.

For more information contact

Laura Roberts
EGU Communications Officer (early career scientists’ contact person at the EGU Office)
Munich, Germany
Tel: +49-89-2180-6717

Drilling into magma: the future of electricity production from volcanic geothermal systems?

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Citation: Scott, S., Driesner, T. & Weis, P. Geologic controls on supercritical geothermal resources above magmatic intrusions. Nature Communications. 6:7837 doi: 10.1038/ncomms8837 (2015)

Blog by Samuel Scott

Electricity production from high-enthalpy geothermal systems typically involves drilling boreholes into permeable reservoirs at depths of 1-2 km and temperatures between 250-300 °C. The fluid that comes up the wellbore consists of a mixture of liquid and vapor, from which the vapor is separated and passed through a steam turbine to generate on average 3-5 MW per well. The Iceland Deep Drilling Project (IDDP) was founded by a group of international scientists who sought to drill to deeper, hotter conditions where water is a single-phase, intermediate density, supercritical fluid. Basic thermodynamic considerations suggest that wells drilled into supercritical geothermal resources could potentially provide an order of magnitude more electricity than a conventional geothermal well. A plan was developed to drill a borehole to 4-5 km depth in the Krafla geothermal system, with the aim of discovering a reservoir at supercritical temperatures (>374 °C) and pressures (>220 bars).

Transparent, opalescent steam discharges from the IDDP-1 borehole at the Krafla volcano in Iceland. (Image: Kristján Einarsson/IDDP)

Transparent, opalescent steam discharges from the IDDP-1 borehole at the Krafla volcano in Iceland. (Image: Kristján Einarsson/IDDP)

Drilling was difficult and did not go as expected. After chunks of quenched glass began to come up the wellbore, they knew that they had drilled into a magmatic intrusion located around 2 km depth. Studies of the glass showed that it was rhyolitic in composition. Temperature measurements suggested a fluid temperature as high as 450 °C, but since the intrusion was encountered at a relatively shallow depth, the fluid pressure was less than the supercritical pressure, and the fluid was categorized as ‘superheated steam’. The big surprise was the fact that the fluid reservoir was nonetheless much more powerful than typical wells drilled to 2 km depth. As can be seen in videos taken during the well testing (, the well discharged large volumes of translucent and opalescent fluid – classic indicators of a supercritical fluid. Well tests indicated that the well could potentially generate 35 MWe of electric power, roughly an order of magnitude greater than a typical geothermal well. However, there were many questions that surrounded this discovery. How did this fluid reservoir form? How could it form at such a shallow depth? It was unclear whether the IDDP reservoir was an anomaly, or whether similar resources could exist in other high-enthalpy systems.

This led myself and a group of collaborators at ETH Zurich to use numerical models to understand the hydrology of the IDDP reservoir. The computer code had already been successfully applied to understand high-temperature fluid flow in other settings, such as mid-ocean ridges and the formation of copper-rich porphyry deposits. We set-up the model such that only a few key parameters were needed, aimed at capturing the main sources of geologic variability between different geothermal settings. The key data that go into the model are the depth of the intrusion, the host rock permeability (a measure of how fractured the system is as a result of tectonic activity) and the brittle-ductile transition temperature (which determines the temperature where rock becomes impermeable due to plastic deformation closing connecting fluid flow pathways).

These models show how these primary geologic controls determine the extent and thermal conditions of supercritical reservoirs. For example, our study identified a brittle-ductile transition temperature greater than 450 °C as a key control on reservoir formation. Since basalt has a brittle-ductile transition temperature >450 °C, while granite becomes impermeable around 360 °C, we expect that the best resources will be found in basaltic rocks. Additionally, if the rock surrounding the intrusion is very permeable, we expect the supercritical resources to be close to the intrusion, relatively limited in spatial extent, and at temperatures near 400 °C. If the rock surrounding the intrusion is moderately permeable, the reservoirs will be larger and at higher temperatures. However, the fluid production rate for a well drilled into a supercritical reservoir will be higher when rock permeability is higher. Thus, there is a trade-off between fluid temperature and well productivity that is governed primarily by rock permeability. These basic concepts can inform future efforts to discover and exploit these resources.


If the rock (white) surrounding an impermeable body of magma (grey) is only highly permeable, supercritical water (red) is restricted to a thin layer around the magma (left panel). However, if the rock is moderately permeable, a large area can be heated to supercritical conditions (right panel). (Illustration: from Scott et al. 2015, Nature Comm.)

Our models were able to reproduce measured data from the IDDP well when the geologic controls are set to appropriate values for the Krafla system. This supports the model set-up, as well as the conclusion that supercritical geothermal resource properties depend on geologic controls. Moreover, the models show that conventional geothermal resources result simply from the mixing of supercritical fluids ascending from the intrusion and cooler fluids circulating near the intrusion but not heated to supercritical conditions. This is a new way to look at conventional high-enthalpy geothermal reservoirs.

In future studies, we will seek to better understand the role of supercritical water in controlling the thermal structure and temporal evolution of high-enthalpy geothermal systems. As our understanding progresses, we will move towards modeling specific geologic settings, including the Reykjanes geothermal system where the next IDDP well will be drilled. Since the Reykjanes geothermal field contains groundwater that is known to have a large seawater component, fluid salinity is likely to play a key role on supercritical resource formation and properties. Salt changes the thermodynamic properties of water such as density and viscosity and allows boiling to occur at higher temperatures and pressures than for pure water. This may affect the formation of similar supercritical reservoirs in unexpected ways.

Although this was not the outcome the IDDP expected, the fact that such a reservoir was encountered on the first intentional effort suggests they may be a common feature that we have been passing up by targeting reservoirs at shallower depths. It also means that targeting supercritical geothermal resources may be even more economically attractive than expected by the IDDP, since wells do not need to be drilled as deep as expected. Exploiting supercritical water resources has the potential to massively improve the economics of power production from magma-driven geothermal systems. Time will tell whether or not they can be found in systems all over the world, but we anticipate that the search for these fluid reservoirs will continue.

The mysterious subsidence of the seafloor due to oil production – How to predict it with a simple model?

by Daniel Keszthelyi
Physics of Geological Processes group at the Department of Physics, University of Oslo

Over 40 years of oil production from the Ekofisk field caused the overlying seafloor to sink over 9 meters during the years and while there have been numerous researches on the topic; the clear understanding of what happens with the reservoir rocks during production is still missing. We created a simple model of compaction with physics-based assumption to estimate the magnitude of the subsidence.

The Ekofisk field situated some 320 km off the coast of Norway is one of the largest petroleum fields of the country. Oil is produced from carbonate rocks (chalk) lying almost 3 km below the seabed to an oil platform standing in 76 meter deep water. The depletion of oil from the carbonate rocks caused a dramatic decrease in the pore pressure in these rocks and in turn a large increase in the effective stress acting to them. This increased effective stress then led to their compaction which was much more significant than expected by previous models.

The compaction has positive effect on the oil production as it pushes out oil from the rock; however it also puts at risk the surface facilities (oil platform and pipelines) and decreases the permeability of the rock making the flow of fluids inside them more difficult.

Our new model of compaction is based on very simple assumptions and describes rock as a collection of pores where these pores are material weaknesses. Imagine a sheet of paper with a small cut made in the middle of the paper. Then if you try to tear or shear the paper slowly you can see that this cut starts to grow until the sheet of paper is torn into two pieces. Similar things happen to the rock if effective stresses are increased: the pores – like the small cut in the middle of the sheet of paper – will become nuclei of new fractures and eventually a fracture network will be created. According to linear elastic fracture mechanics the larger the pore the less stress is needed to involve it into fracturing and vice-versa the larger the stress the smaller pores can be fractured: so with increasing effective stresses considerably more fractures can be created.

The Ekofisk field: location, mechanism of compaction and predicted subsidence (by Daniel Keszthelyi)

The Ekofisk field: location, mechanism of compaction and predicted subsidence (by Daniel Keszthelyi)

Fluids originally inside the pores can flow into these new fractures and if the fluid is water or partly water it can dissolve the material of rock: in carbonates calcite. The exact mechanism is called pressure solution which vaguely speaking means that the solubility of calcite depends on the pressure and therefore it can dissolve at grain-grain contacts along the new fracture and precipitate anywhere else. According to our model this dissolution will lead to the compaction of the carbonate rock.

The speed of dissolution can be calculated from pressure solution theories and the number of fractures can be calculated by statistical means and therefore the speed of deformation (the strain rate) can be predicted knowing some parameters without using any fitting parameters. All we have to know is porosity, pore size distribution, effective stress, water saturation, temperature and how the solubility of calcite depends on pressure and temperature: all of these can be measured independently in laboratory experiments.

If we apply this model to the Ekofisk field using an estimated pressure history of the reservoir we get quite good agreement with the measured subsidence values. This means that with a very simple model with no fitting we are able to predict the subsidence of the Ekofisk field. Furthermore, with simple modifications might also help to better understand other subsidence cases related to oil, gas or water production.

This post is based on the EGU talk Compaction creep by pore failure and pressure solution applied to a carbonate reservoir by Daniel Keszthelyi, Bjørn Jamtveit and Dag Kristian Dysthe. Daniel Keszthelyi is a PhD candidate at the Physics of Geological Processes group at the Department of Physics, University of Oslo. For further information please contact daniel.keszthelyi

Funding opportunity for Early Career Researchers to attend GSA Baltimore

The Heritage Stone Task Group in southern Europe is a Task Group within the IUGS. In March, HSTG  had a proposal accepted as Project 637 of the International Geoscience Programme (IGCP 637). With this acceptance, IGCP 637 offered $US6,000 in 2015 to support conference participation.

HSTG has decided that this funding should be used in 2015 to support attendance to our session in the GSA Baltimore conference. Amounts not exceeding $US2000 will likely be available. We have been asked by the IGCP Secretariat to give preference to supporting scientists from developing countries or who are young or women scientists. Recipients will also be expected to make a conference presentation in our session, related to natural stones, architectonic heritage and related issues.

Early Career researchers who are interested should send a message showing interest and a short cv, with a potential title for the contribution in the HSTG session, to the HSTG secretary general Barry Cooper:

Applicatons will be received up to 30 June 2015.

Please contact Dr Lola Pereira for further information (