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for the change in water level in a well of finite diameter after a known volume of water is suddenly injected or withdrawn.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

Monitoring and modeling migration of injected CO2 in the subsurface is critical for assessing the risk of leakage from geologic carbon sequestration sites, but it is also very challenging. Integrating complementary hydrological and geophysical monitoring data in a coupled hydrogeophysical inversion can help to address this challenge. We consider a synthetic CO2 injection study to analyze the effect of adding cross-borehole electrical resistance and seismic data to inversions of pressure and gas-composition data. The geophysical data are found to significantly improve convergence and stability of the inversions. Parameterizing mean aquifer permeability and differences from this mean value are found to be superior to inverting for the permeability of each layer directly. These results will be the starting basis for analysis of the actual field data.

Geophysical data improve stability and convergence of hydrological property estimation: a synthetic co2 injection study

Six hydraulic fracturing experiments were conducted at the Grimsel Test Site (GTS), Switzerland, to study the geometry of new created fractures and interactions with the pre-existing fracture network. In addition, the hydromechanical effects during stimulation were investigated. All six tests followed a similar injection protocol (Figure 1) to study the response of the rock mass at different injection locations and the influence of injection fluid characteristics. For this, water and a xanthan-salt-water (XSW) mixture were injected. The viscosity of the XSW mixture was 35 times higher compared to water. Except HF6, all HFs were initiated borehole intervals covering intact rock. Several monitoring systems were installed to study transient pressure propagation, deformation within the rock mass and along shear zones, and seismic activities.

Preliminary results of six decameter scale hydraulic fracturing experiments (HF) at the Grimsel Test Site (GTS)

Monitoring and characterization of flow and transport processes in the subsurface has been a key focus of hydrogeological research for several decades. Such processes can be relevant for numerous applications, such as hydrocarbon and geothermal reservoir characterization and monitoring, risk assessment of soil contaminants, or nuclear waste disposal strategies.Monitoring of flow and transport processes in the subsurface is often challenging, as they are usually not directly observable. Here, we present an approach to monitor saline tracer migration through a weakly fractured crystalline rock mass by means of Ground Penetrating Radar (GPR), and we evaluate the data quantitatively in terms of a flow velocity field and localized difference GPR breakthrough curves (DRBTC).Two comparable and repeated tracer injection experiments were performed within saturated rock on the decameter scale. Time-lapse single-hole reflection data were acquired from two different boreholes during these experiments using unshielded and omnidirectional borehole antennas. The individual surveys were analyzed by difference imaging techniques, which allowed ultimately for tracer breakthrough monitoring at different locations in the subsurface. By combining the two complimentary GPR data sets, the 3D tracer velocity field could be reconstructed.Our DRBTCs agree well with measured BTCs of the saline tracer at different electrical conductivity monitoring positions. Additionally, we were able to calculate a DRBTC for a location not previously monitored with borehole sensors. The reconstructed velocity field is in good agreement with previous studies on dye tracer data at the same research locations. Furthermore, we were able to resolve separate flow paths towards different monitoring locations, which could not be inferred from the electrical conductivity sensor data alone. The GPR data thus helped to disentangle the complex flow field through the fractured rock.Out technique can be adapted to other use cases such as 3D monitoring of fluid migration (and thus permeability enhancement) during hydraulic stimulation and tracing fluid contaminants &#8211; e.g. for nuclear waste repository monitoring.

Inferring saline tracer transport characteristics from time-lapse GPR experiments

Overview of the hydraulic stimulation experiments at the Grimsel Test Site

https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GL091468

Joseph Doetsch

Papers

Geophysical data improve stability and convergence of hydrological property estimation: a synthetic co2 injection study

Preliminary results of six decameter scale hydraulic fracturing experiments (HF) at the Grimsel Test Site (GTS)

Inferring saline tracer transport characteristics from time-lapse GPR experiments

Overview of the hydraulic stimulation experiments at the Grimsel Test Site

Poroelasticity Contributes to Hydraulic-Stimulation Induced Pressure Changes