Carbon capture and storage (CCS) is broadly recognised as having the potential to play a key role in meeting climate change targets, delivering low carbon heat and power, decarbonising industry and, more recently, its ability to facilitate the net removal of CO2 from the atmosphere. However, despite this broad consensus and its technical maturity, CCS has not yet been deployed on a scale commensurate with the ambitions articulated a decade ago. Thus, in this paper we review the current state-of-the-art of CO2 capture, transport, utilisation and storage from a multi-scale perspective, moving from the global to molecular scales. In light of the COP21 commitments to limit warming to less than 2 °C, we extend the remit of this study to include the key negative emissions technologies (NETs) of bioenergy with CCS (BECCS), and direct air capture (DAC). Cognisant of the non-technical barriers to deploying CCS, we reflect on recent experience from the UK's CCS commercialisation programme and consider the commercial and political barriers to the large-scale deployment of CCS. In all areas, we focus on identifying and clearly articulating the key research challenges that could usefully be addressed in the coming decade.

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Carbon capture and storage (CCS): the way forward

A copy of Guangbo jiemu bao [Broadcast Program Report] was being passed from hand to hand among a group of young people eager to be the first to read the article introducing the program "What Is Revolutionary Love?" It said: "… Young friends, you are certainly very concerned about this problem'. So, we would like you to meet the young women workers Meng Xiaoyu and Meng Yamei and the older cadre Miss Feng. They are the three leading characters in the short story ‘The Place of Love.’ Through the description of the love lives of these three, the story induces us to think deeply about two questions that merit further examination.

This is How the Discussion Started

Recent developments in the direct-current geoelectrical imaging method

• Stability of steady frictional sliding, inertia and the quasi-static limit • work on ps 4; see course web site

The Mechanics Of Earthquakes And Faulting

A solution is presented for the change in water level in a well of finite diameter after a known volume of water is suddenly injected or withdrawn. A set of type curves computed from this solution permits a determination of the transmissibility of the aquifer.

Response of a finite-diameter well to an instantaneous charge of water. Paper No. H-21

Contamination of potable groundwater by leaking CO2 is a potential risk of carbon sequestration. With the help of a field experiment, we investigate if surface electrical resistivity tomography (ERT) can detect dissolved CO2 in a shallow aquifer. For this purpose, we injected CO2 at a depth of 5 and 10 m and monitored its migration using 320 surface electrodes on a 126 m × 20 m grid. A fully automated acquisition system continuously collected data and uploaded it into an online database. The large amount of data allows for time-series analysis for data quality and noise estimation. A baseline inversion reveals the geology at the site consisting of aeolian sands near the surface and glacial sands below 5 m depth. Time-lapse inversions clearly image the dissolved CO2 plume with decreased electrical resistivity values. We can follow the CO2 plume as it spreads and moves with the groundwater, and the spatial distribution of the plume agrees well with direct measurements of the groundwater resistivity. Future work will include improved time-series analyses and quantitative comparison with the groundwater resistivity measurements.

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3-D Time-lapse Electrical Resistivity Monitoring of Injected CO2 in a Shallow Aquifer

For accurate prediction of flow and contaminant transport in aquifers, a high resolution method is necessary, that is able to detect small-scale high-contrast layers. Such layers can act as low-velocity waveguides in the GPR signal and can be related to a zone of preferential flow or impermeable clay lenses. Here, we characterize a saturated gravel aquifer in 3D by applying 2D full-waveform inversion and an amplitude analysis approach that explores the information content present in the measured GPR data. The full-waveform inversion results of the permittivity and conductivity show decimeter-scale high resolution images and similar results at the borehole crossing and at the intersection of the diagonal planes. In all six planes, a high permittivity layer between 5m-6m depth was resolved, which acted due to the high contrast to the surrounding as a low-velocity waveguide indicating a zone of higher porosity. The amplitude analysis of the measured data showed significant wave propagation for transmitter located in and outside this zone. By using this information, the method was able to detect the waveguide layers and their boundaries in the measured data, which were confirmed by the full-waveform inversion results. Permeability logs indicate a zone of preferential flow between 5m-6m depth, which shows a good agreement with the high permittivity/porosity zone detected by the full-waveform inversion.

Joseph Doetsch

Papers

3-D Time-lapse Electrical Resistivity Monitoring of Injected CO2 in a Shallow Aquifer

3D characterization of an aquifer using full-waveform inversion and amplitude analysis

Time-lapse reflection and transmission borehole GPR for saline tracer monitoring in fractured rock

High-Resolution Time-Lapse GPR Monitoring of Saline Tracer Flow in Fractured Rock

On the variability of seismic response during multiple decameter-scale hydraulic stimulations in crystalline rock