ERE
Energy, Resources and the Environment

CO2 storage

Words on Wednesday: The ocean carbon sink – impacts, vulnerabilities and challenges

June 17, 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.

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Heinze, C., Meyer, S., Goris, N., Anderson, L., Steinfeldt, R., Chang, N., Le Quéré, C., and Bakker, D. C. E., 2015. The ocean carbon sink – impacts, vulnerabilities and challenges, Earth Syst. Dynam., 6, 327-358, doi:10.5194/esd-6-327-2015.

Abstract:

Carbon dioxide (CO2) is, next to water vapour, considered to be the most important natural greenhouse gas on Earth. Rapidly rising atmospheric CO2 concentrations caused by human actions such as fossil fuel burning, land-use change or cement production over the past 250 years have given cause for concern that changes in Earth’s climate system may progress at a much faster pace and larger extent than during the past 20 000 years. Investigating global carbon cycle pathways and finding suitable adaptation and mitigation strategies has, therefore, become of major concern in many research fields. The oceans have a key role in regulating atmospheric CO2 concentrations and currently take up about 25% of annual anthropogenic carbon emissions to the atmosphere. Questions that yet need to be answered are what the carbon uptake kinetics of the oceans will be in the future and how the increase in oceanic carbon inventory will affect its ecosystems and their services. This requires comprehensive investigations, including high-quality ocean carbon measurements on different spatial and temporal scales, the management of data in sophisticated databases, the application of Earth system models to provide future projections for given emission scenarios as well as a global synthesis and outreach to policy makers. In this paper, the current understanding of the ocean as an important carbon sink is reviewed with respect to these topics. Emphasis is placed on the complex interplay of different physical, chemical and biological processes that yield both positive and negative air–sea flux values for natural and anthropogenic CO2 as well as on increased CO2 (uptake) as the regulating force of the radiative warming of the atmosphere and the gradual acidification of the oceans. Major future ocean carbon challenges in the fields of ocean observations, modelling and process research as well as the relevance of other biogeochemical cycles and greenhouse gases are discussed.

Mean unweighted surface water fCO2 (μatm) for the years 1970–2002 (a) and 2003–2011 (b) using the SOCATv2 monthly 11 degree gridded data set (Bakker et al., 2014). The maps were generated by using the online Live Access Server.

Mean unweighted surface water fCO2 (μatm) for the years 1970–2002 (a) and 2003–2011 (b) using the SOCATv2
monthly 11 degree gridded data set (Bakker et al., 2014). The maps were generated by using the online Live Access Server.

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

What to see at EGU?: Words on Wednesday – The Green River Natural Analogue as A Field Laboratory To Study the Long-term Fate of CO2 in the subsurface

April 8, 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.

If you are interested in today’s WoW, some of the results will be presented during the EGU in session ERE5.2 Field methods and analysis of field data for CO2 geological storage, on Thursday at 15.30h in room R8. So go check it out! 🙂

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Busch, A. Kampman, N. Hangx, S.J.T., Snippe, J., Bickle, M. Bertier, P., Chapman, H., Spiers, C.J., Pijnenburg, R.Samuelson, J. Evans, J.P., Maskell, A., Nicholl, J., Pipich, V., Di, Z., Rother, G., Schaller, M., 2014. The Green River Natural Analogue as a field laboratory to study the long-term faith of CO2 in the subsurface. Energy Procedia 63, 2821-2830.

Abstract:

Understanding the long-term response of CO2 injected into porous reservoirs is one of the most important aspects to demonstrate safe and permanent storage. In order to provide quantitative constraints on the long-term impacts of CO2-charged fluids on the integrity of reservoir-caprock systems we recovered some 300m of core from a scientific drill hole through a natural CO2 reservoir, near Green River, Utah. We obtained geomechanical, mineralogical, geochemical, petrophysical and mineralogical laboratory data along the entire length of the core and from non CO2-charged control samples. Furthermore, we performed more detailed studies through portions of low permeability layers in direct contact with CO2-charged layers. This was done to constrain the nature and penetration depths of CO2-promoted fluid-mineral reaction fronts. The major reactions identified include the dissolution of diagenetic dolomite cements and hematite grain coatings, and the precipitation of ankerite and pyrite and have been used as input for geochemical 1D reactive transport modelling, to constrain the magnitude and velocity of the mineral-fluid reaction front.

In addition, we compared geomechanical data from the CO2-exposed core and related unreacted control samples to assess the mechanical stability of reservoir and seal rocks in a CO2 storage complex following mineral dissolution and precipitation for thousands of years. The obtained mechanical parameters were coupled to mineralogy and porosity. Key aim of this work was to better quantify the effect of long-term chemical CO2/brine/rock interactions on the mechanical strength and elastic properties of the studied formations.

 

Entrada formation from surface to top Carmel Fm with CO2-charged sandstone layer, overlain by a low permeability clayey siltstone showing bleaching and CO2 reaction features. A sharp contact between bleached and unbleached is observed.

Entrada formation from surface to top Carmel Fm with CO2-charged sandstone layer, overlain by a low permeability clayey siltstone showing bleaching and CO2 reaction features. A sharp contact between bleached and unbleached is observed.