Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - S4CE (Science for Clean Energy)

Teaser

Engineering sub-surface geo-energy operations is essential to provide energy for our society to prosper. Sub-surface operations, however, carry intrinsic environmental risks. Science4CleanEnergy, S4CE, is a multi-disciplinary consortium established to understand the underlying...

Summary

Engineering sub-surface geo-energy operations is essential to provide energy for our society to prosper. Sub-surface operations, however, carry intrinsic environmental risks. Science4CleanEnergy, S4CE, is a multi-disciplinary consortium established to understand the underlying mechanisms underpinning sub-surface geo-energy operations and to measure, control and mitigate their environmental risks.

S4CE will develop across Europe, where it will have access to several complementary field sites. The operations (carbon sequestration, enhanced geothermal energy, enhanced oil recovery using CO2, and gas/water production from fractured limestone) share environmental risks due to induced seismicity, fugitive emissions, fluid transport in the sub-surface, durability of the concrete structures, and leaks to water table.

S4CE proposed a comprehensive analysis of environmental impact, risks and potential benefits to assess the sustainability of sub-surface geo-energy operations. During the project, S4CE will develop instruments to cost-effectively measure and sample rocks and fluids, a toolbox to interpret seismic data, identify fluid pathways, and quantify the environmental impact of each operation via both Life Cycle Assessment and Multi-Risk analysis. Best practices and best procedures will be identified and reported to policymakers and to all stakeholders, including industry and NGOs. Training the next generation of scientists, disseminating the results widely, collaborating with North American colleagues and exploiting technological innovations will underpin the success of this consortium.

Work performed

Internal monitoring procedures have been put in place to reduce ethical risks. An up-to-date website disseminates to external stakeholders, while a secure SharePoint maintains active collaboration between S4CE. An arsenal of communication channels has been activated to all stakeholders. Particular attention has been in training the next generation of scientists, in establishing and maintaining international collaborations, in publishing the results via Open Access channels, and to maintaining open dialogue with the public.

New monitoring technologies have been developed within WP3. A fluid sampling technology preserving pressure integrity to minimize sampling impact on microbial life has been refined and deployed for demonstration. Three-dimensional imaging methods of fluid flow in concrete structures were developed and successfully demonstrated. A novel optical instrument capable of mapping gas fugitive emissions has been demonstrated. The study of DNA-based tracers was completed and demonstrated how safe using these tracers is.

Samples and data-sets have been collected from five field-sites: Carbfix (Iceland), St. Gallen (Switzerland), Cornwall (UK), Hellisheidi/Nesjavellir (Iceland) and Mont Terri (Switzerland). Experimental workflows have been established within WP4. Highlights include:
I. An integrated analysis to investigate the kinetics of fluid-rock reactions;
II. Quantification of CO2 and CH4 sorption at subsurface conditions;
III. Workflow to extract and quantify DNA content from fluid samples;
IV. Demonstration that sour gas in basalt stimulates microbial activity;
V. Development of cyclic CO2 injection schemes to promote consumption of pore space within basaltic rocks.

Within WP5, models have been built for fluid transport within cement and rock samples. The intercalation of CO2/H2O mixtures has been investigated. Preliminary structural analysis of nanoconfined fluids was performed. The transport properties of methane correlate with macroscopic descriptors of the pore structure.

Seismo-hydraulic pressure mapping (SHPM) has been developed and tested at Cooper Basin (Australia) and St. Gallen (Switzerland) sites, demonstrating that characteristic pressure developments can be inferred throughout the reservoirs.

Ground Motion Prediction Equations (GMPEs) have been used to monitor the status of the reservoir on a synthetic data set.

To assess risks and environmental impacts, two approaches are implemented: (a) life cycle assessment (LCA) and (b) multi-risk assessment (MRA). S4CE is developing LCA software, whose specifications have been defined. LCA analysis has been conducted on field sites.

New technologies are developed within WP6 to monitor risks and prevent accidents:
1. Identification of the most appropriate techniques for monitoring casings;
2. Development of prototypes;
3. Development of a painted, electrical imaging-based sensing skin;
4. Significant improvements on the DNA tracer particle dispersion stability;
5. Provision of the relation between injection rate and fracture growth rate;
6. Proposed methods to calculate potential of induced seismicity to build pathways for fluid migration. Optimal conditions to reduce this potential have been met for high, slowly changing injection rates.
7. Satisfactory agreement between the laboratory results and modelling was obtained in case of replication of stress-strain behaviour in tri-axial compression tests.

The technologies will be field tested within WP7 in the second part of the project.

WP8 has the goal of enabling exchanges of best practice recommendations between S4CE partners and leader institutions in North America and elsewhere. An External Science Board has bee established; procedures have been out in place for enabling exchanges between Early Stage Researchers. Data have been collected to identify best practice procedures for groundwater/subsurface monitoring and remediation.

Final results

S4CE is having positive impacts:
a) Scientific field sites are being developed. For example, at the Cornwall site the first well has reached 4.6 Km depth. S4CE contributes to monitor the environmental impact of such operation.
b) S4CE is developing new technologies for quantifying environmental risks. Partner MIRICO developed and tested prototypes to detect and quantify gaseous emissions, partner TWI is developing a prototype to monitor casings, and partner UEF is developing technologies to monitor the integrity of cements.
c) S4CE has developed models and algorithms to predict transport of fluids through cements and in the sub-surface, to enable prediction of CO2 fixation in minerals, and to relate these phenomena to environmental risks, including induced seismicity.
d) To quantify the long-term environmental impact, and therefore to allow policymakers to make informed decisions in the best interest of the European socio-political landscape, S4CE has developed a life cycle assessment approach, and has implemented it on data from field sites.
e) S4CE has maintained open dialogue with all stakeholders, with several workshops and dissemination events. In addition to training post-doctoral researchers and Ph.D. students, S4CE is also training masters-level students enrolled in ‘Global Management of Natural Resources’, offered by UCL.

Website & more info

More info: http://science4cleanenergy.eu/.