ERE
Energy, Resources and the Environment

CCS

The Pore Space Scramble

June 15, 2015
by Alexandra Gormallya and Michelle Benthamb
aLancaster Environment Centre, Lancaster University, Lancaster, LA1 4YQ, UK; bBritish Geological Survey, Keyworth, Nottingham, NG12 5GG, UK

The underground is being used more to help us meet some of the challenges facing humans from tackling climate change, waste disposal to ensuring energy security. The notion of ‘pore space’ and its commodification, has gained much momentum over the last few years in policy circles, industry and the natural (geo)sciences alike. However ‘pore space’ and the use of the underground is now also being discussed within the social sciences too. Human geographers in particular are starting to critically discuss some of the ways in which society uses, perceives and interacts with the subsurface in the past, present, and different ways of how this might happen in the future. Through this examination, social scientists are beginning to interact with geoscientists. This has led to a collaborative engagement between human geographers in the Lancaster Environment Centre, with geoscientists at the British Geological Survey. Through this collaboration the notion of The Pore Space Scramble was born.

So, what is pore space and why might there be such a scramble for its use? Pore spaces are voids between rock grains that contain liquid or gas. The connection of pores then form pathways in which water, oil or gas can move. The interest in pore space therefore, is of interest due to its potential to store materials such as heat, gas or water. Uses of the pore space form a complex system so to simplify this we frame our discussion around the use of pore space for the long-term storage of CO2 as a result of Carbon Capture and Storage (CCS). CCS is a suggested route to decarbonising the power and industrial sectors.

Going down in scale: from the outcrop to the pore space (by the British Geological Survey)

Going down in scale: from the outcrop to the pore space (by the British Geological Survey)

There is strong political will behind CCS both at the European level and in the UK itself [1], the UK setting out a 3 phase road map to commercialise CCS going forward. Given this political drive, it is not only necessary to understand the technical capabilities and practical ability to take this technology forward it also raises many questions around society and governance of such a system into the future. For example, who has precedence over this space and how does it compete with other energy infrastructure on both the surface and subsurface (eg. oil & gas industry, windfarms)? What are the legal and regulatory standpoints of this space i.e. who owns the pore space and therefore legally be able to utilise its use? What are the long-term stewardship plans of this space (eg. 10, 100, 1000 years), how does this effect liability and how might the precedence of such industries change over time? Ultimately, how do we ethically and justly govern such a space both presently and when projected into the future?

Demands on the subsurface (by the British Geological Survey)

Demands on the (sub)surface (by the British Geological Survey)

We do not currently have answers for these questions but are initiating and undertaking research in this area as well as highlighting the need for policymakers, scientists, academic and publics to negotiate the challenges the subsurface will face going forward.

Reference:

  1. DECC (2012). CCS Roadmap: Supporting deployment of Carbon Capture and Storage in the UK < www.gov.uk/government/uploads/system/uploads/attachment_data/file/48317/4899-the-ccs-roadmap.pdf > Accessed: 10/06/2015.

Words on Wednesday: Flow-through experiments on water–rock interactions in a sandstone caused by CO2 injection at pressures and temperatures mimicking reservoir conditions

May 20, 2015

Words on Wednesday aims at promoting interesting/fun/exciting publications on topics related to Energy, Resources and the Environment. If you would like to be featured on WoW, please send us a link of the paper, or your own post, at ERE.Matters@gmail.com.

This week, we would like to share with you the latest manuscript of Farhana Huq, who was our guest-blogger on Monday! 🙂

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Huq, F., S.B. Haderlein, O.A. Cirpka, M. Nowak, P. Blum, P. Grathwohl, 2015. Flow-through experiments on water–rock interactions in a sandstone caused by CO2 injection at pressures and temperatures mimicking reservoir conditions. Applied Geochemistry, v58, 136–146.

Highlights:

  • Altmark sandstone showed CO2-induced fluid–rock interactions under in-situ conditions.
  • Dissolution of anhydrite and calcite cements was inferred from fluid analysis.
  • Sample permeability increased by a factor 2.

Abstract:

Flow-through experiments were performed in a newly designed experimental setup to study the water–rock interactions caused by CO2 injection in sandstones obtained from the Altmark natural gas reservoir under the simulated reservoir conditions of 125°C and 50 bar CO2 partial pressure. Two different sets of experiments were conducted using CO2-saturated millipore water and CO2-saturated brine (41.62 g L-1 NaCl and 31.98 g L-1 CaCl2·2H2O), mimicking the chemical composition of the reservoir formation water. The major components in the sandstone were quartz (clasts + cement), feldspars, clay minerals (illite and chlorite), and cements of carbonates and anhydrite. Fluid analysis suggested the predominant dissolution of anhydrite causing increased concentrations of calcium and sulfate at early time periods at non-equilibrium geochemical conditions. The Ca/SO4 molar ratio (>1) indicated the concurrent dissolution of both calcite and anhydrite. Dissolution of feldspar and minor amounts of clay (chlorite) was also evident during the flow-through experiments. The permeability of the sample increased by a factor of two mostly due to the dissolution of rock cements during brine injection. Geochemical modeling suggests calcite dissolution as the major buffering process in the system. The results may in future studies be used for numerical simulations predicting CO2 storage during injection in sandstone reservoirs.

Reaction vessel used in the CO2/brine/rock reaction experiments on the Altmark sandstone - courtesy Farhana Huq

Reaction vessel used in the CO2/brine/rock reaction experiments on the Altmark sandstone – courtesy Farhana Huq

I’m a Geoscientist: Suzanne Hangx – ‘Subsurface’ Officer

March 16, 2015

It’s I’m a Geoscientist week! Or more exactly: weeks. From March 9 until March 20, the EGU supports I’m a Geoscientist to help students engage with scientists about real science. The Energy, Resources and Environment Division of the European Geosciences Union encompasses a broad range of different ERE-related topics, from surface to subsurface, spanning all aspects of geosciences. In order to demonstrate how broad the Division actually is, and what you can do as a geoscientist to be involved with energy, resources or the environment, we asked the members of the ERE committee to introduce themselves and explain how their day-to-day work relates back to ERE.

From above ground, we will dive down below into the subsurface with Suzanne Hangx, post-doctoral researcher at the High Pressure and Temperature Laboratory at Utrecht University.

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Suzanne HangxIn my research, I have always been driven by curiosity about the physical and chemical processes that control rock material behaviour in the subsurface, along with the direct relevance of this field to socially relevant issues. Naturally, working on energy, sustainability and the environment from a geoscientific point of view was a logical step. I want to contribute to solving geo-energy problems, by investigating and quantifying related risks, such as climate change caused by greenhouse gases or surface subsidence caused by oil/gas/ground water production, and contribute to socially acceptable solutions or technologies.

For about 10 years I have mainly been working on CO2 Capture and Storage (CCS). It is considered to be one possible route to get rid of large quantities of CO2 by injecting them into the subsurface, reducing its effect on climate change. Suitable locations are depleted oil or gas reservoirs, or aquifers, at several km’s below the surface. However, it is important to ensure that after injection the CO2 also stays there – not just today or tomorrow, but for thousands of years. Once a potential injection site is suggested, it is important to see if the reservoir (the ‘container’) and the seal keeping the CO2 in place (the ‘lid’), are up for the job, so to speak. I investigate if the injected CO2 does anything to the rocks to alter their mechanical behaviour, i.e. how they break, under which force they break and if they get weaker by the presence of the CO2.

When you inject CO2 into a depleted oil or gas reservoir, part of it will start to dissolve into the water that is present in that reservoir, while the rest will stay in a dense liquid or supercritical phase. When CO2 dissolves in water, the water will become acidic. This acidic fluid can chemically interact with the surrounding rocks, and certain minerals may dissolve and new ones may be formed. In addition, the way cracks propagate through the rock may be affected, changing their strength and the way they break. If a rock gets sufficiently weakened by the chemical interaction with CO2 it may compact or break, which we would like to know in advance!

In Utah, natural CO2 accumulations are present within the Entrada Sandstone ('Layer Cake' by Suzanne Hangx, via ImagGeo)

In Utah, natural CO2 accumulations are present within the Entrada Sandstone (‘Layer Cake’ by Suzanne Hangx, via ImagGeo)

Such chemical interactions may occur on different timescales. Processes that happen in days, weeks or months can still be dealt with in a laboratory setting. However, to be able to predict what will happen on the timescale of thousands of years, we are currently trying to learn as much as we can from naturally occurring CO2 fields, such as those in Utah (USA), Australia and Europe. These fields can contain over 90% pure CO2 and have mostly done so for thousands of years. Studying these fields can help us understand better how subsurface storage of anthropogenic CO2 will evolve over time.

Nowadays I’m trying to apply what I learned during my research on the chemical-mechanical interactions occurring in rocks to understand surface subsidence, and related induced seismicity, resulting from the production of fluids such as oil and gas. Though dealing with a different setting, the mechanisms and processes are similar to those of interest for CCS. Given their interdisciplinary nature, the ERE sessions at the EGU General Assembly are the perfect platform for me to show my most recent research in both areas!

I’m a Geoscientist: Viktor Bruckman – ‘Above Ground’ Officer

March 13, 2015

It’s I’m a Geoscientist week! Or more exactly: weeks. From March 9 until March 20, the EGU supports I’m a Geoscientist to help students engage with scientists about real science. The Energy, Resources and Environment Division of the European Geosciences Union encompasses a broad range of different ERE-related topics, from surface to subsurface, spanning all aspects of geosciences. In order to demonstrate how broad the Division actually is, and what you can do as a geoscientist to be involved with energy, resources or the environment, we asked the members of the ERE committee to introduce themselves and explain how their day-to-day work relates back to ERE.

After a flight through the scientific world of mining, nuclear energy, CO2 storage and groundwater flow, today we will stay above ground, with our ‘Above Ground’ Officer Viktor Bruckman, who is working at the Austrian Academy of Sciences.

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Viktor BruckmanThe European Geosciences Union (EGU) Division on Energy, Resources and the Environment (ERE) deals with some of the most important aspects for sustaining humanity. The current demographic trend of a growing world population with increasing demands of energy and resources defines a challenging task in developing policies for a sustainable future. Such frameworks need to be implemented on a sound scientific basis and the ERE division provides a forum for discussing state-of-the-art projects and results at the annual general assemblies and beyond. At the ERE division, I am responsible for the aboveground section, which includes most of the renewable sources of energy (e.g. wind power, hydropower, solar power) and other resources, such as biomass.

My own background is forestry, with a strong specialization in the areas of carbon cycling and sequestration, as well as the production of biomass. I am working for the Commission for Interdisciplinary Ecological Studies at the Austrian Academy of Sciences (ÖAW) that taught me to approach problems in a holistic and interdisciplinary fashion. And these are the best lessons learned in order to serve the ERE business. Indeed, the provision of sustainable resources are a very interdisciplinary matter, specifically because it is based on interventions on land and consequently causes land use change (LUC), a term recently stressed a number of times, in particular with Climate Change.

This thought alone highlights the complexity of the topic as renewable resources are commonly seen as the potential successors of the fossil sources in order to move our society towards a development based on a solid bioeconomy. In-depth analysis, however, shows that renewables are not per se better than non-renewable sources and in some cases they are even worse. This is true even from an economical point of view, especially when internalizing all associated costs, including e.g. loss of biodiversity etc. Therefore, we need a very sound understanding on how the development of renewable sources of feedstocks and energy impacts the environment and its services, which are delivered at no financial costs to the humanity (so-called ecosystem services).

Over time, biochar particles are fully integrated into the soil system and act as a reservoir for nutrients and water as shown here by intensive occurrence of mycorrhizal hyphae (orange structures). This SEM illustration shows charcoal which was found in a spruce-dominated forest soil in the northern part of Austria and likely origins from the previously common silvicultural practice of slash burning. The age of the charcoal shown here is around 110 years, and it still shows no signs of decomposition, therefore impressively demonstrating its capabilities of securely sequestering carbon. Source: Bruckman, V.J. and Klinglmüller, M. (2014): Potentials to mitigate climate change using biochar – the Austrian perspective. IUFRO Occasional Papers (27) 1-19.

Over time, biochar particles are fully integrated into the soil system and act as a reservoir for nutrients and water as shown here by intensive occurrence of mycorrhizal hyphae (orange structures). This SEM illustration shows charcoal which was found in a spruce-dominated forest soil in the northern part of Austria and likely origins from the previously common silvicultural practice of slash burning. The age of the charcoal shown here is around 110 years, and it still shows no signs of decomposition, therefore impressively demonstrating its capabilities of securely sequestering carbon. Source: Bruckman, V.J. and Klinglmüller, M. (2014): Potentials to mitigate climate change using biochar – the Austrian perspective. IUFRO Occasional Papers (27) 1-19.

Experts agree that atmospheric CO2 emitted from anthropogenic sources plays a major role as a greenhouse gas (GHG). Biomass – and this is the point, where I would like to come back to my own research – has some interesting, but very region-specific potentials to reduce emissions or even sequester additional carbon from the atmosphere. An increased substitution of fossil with renewable resources that are produced under sustainable conditions may reduce large amounts of carbon emissions. My research team goes even further and proposed negative carbon emissions when using biomass as source for energy. This can be realized when combining biomass and CCS (carbon capture and storage), by producing biochar, for instance. Biochar is the solid, carbon-rich residue of biomass pyrolysis, the heating of biomass in an oxygen-low environment. The material is closely related to wood charcoal used for barbecue, just with a distinct different function. It is used as a soil amendment and, because of its unique porous structure and chemical composition it may enhances soil fertility while being very resistant against microbial decomposition. The positive effect may be realized as a consequence of increased nutrient- and water retention, improvement of soil structure and higher cation exchange capacities (CEC). Moreover it can serve as a habitat for soil microorganisms as well as soil fungi (mycorrhiza) that is known to support plant growth in a symbiotic relationship.

This example shows that the ERE division is indeed one of the most interdisciplinary divisions with a large number of connections within the EGU. This is also expressed by the large number of co-organized sessions with various other divisions. I personally enjoy working for ERE and thus add a small contribution of ERE’s success for the sake of science and ultimately a sustainable future.