Report

Teaser, summary, work performed and final results

Periodic Reporting for period 2 - FracRisk (Furthering the Knowledge Base For Reducing the Environmental Footprint of Shale Gas Development (FracRisk))

Teaser

Shale gas is important for local energy security and reducing climate impact as gas increasingly replaces coal for electricity generation thus decreasing greenhouse gas emissions. Methane from shale gas is a much cleaner form of energy than coal, so whilst the technology for a...

Summary

Shale gas is important for local energy security and reducing climate impact as gas increasingly replaces coal for electricity generation thus decreasing greenhouse gas emissions. Methane from shale gas is a much cleaner form of energy than coal, so whilst the technology for a zero carbon future is being developed, the use of shale gas will reduce the overall carbon footprint, whilst keeping the lights on, industry moving and houses warm. Conventional gas production in Europe is also in decline and if shale gas could be produced within Europe then gas prices would go down and the security of the gas supply would increase, as Europe became less dependent on imported gas. The European Commission estimates that there is around 16 trillion cubic meters of technically recoverable shale gas in Europe.
The key challenges with shale gas extraction that the FracRisk project addresses are the understanding of subsurface groundwater contamination and potential induced seismicity, the prevention and mitigation of environmental impacts, scientific recommendations for best practise and improving public understanding.
The general project objectives were
1) Assessment of the environmental impact (footprint) expressed in seismic activities and released substances in the environment.
2) Forward computer modelling based on six focused exemplary scenarios to predict the effect of the migration of chemicals and gases, predict mechanical effects (seismics), and to support risk and uncertainty assessment.
3) Develop and test a framework for risk assessment to be used both by regulators and industry.
4) Development of criteria for appropriate monitoring strategies.
5) Provision of scientific recommendations and a knowledge base for best practices for shale gas development with direct application and relevance to the provision of consistent regulation.

Work performed

In overview FracRisk has integrated the following key elements
1. Assessment of geological data from 7 key shale gas basins across the EU and inclusion of data from America, analysis using a Hydro-Geo-Chemo-Mechanical facies approach.
2. Experimental laboratory investigation program and field data collection for use in construction of conceptual models and ground-truthing of new science concepts within all aspects of the project, particularly mechanical response of rock, geochemistry and development of new mitigation measures.
3. Development of new model concepts and codes for improved understanding of the thermo-hydro-mechanical- and chemical processes involved in hydraulic fracturing. Specific focus on the actual fracturing, the related multiphase flow and transport processes of the released gas and water and on the upscaling of these processes in a hydraulic fracturing environment
4. Use existing and the newly developed codes together with uncertainty assessment tools to model six focused scenarios and to perform risk assessment.
5. Developed and tested a framework for risk assessment to be used both by regulators, industry and public outreach.
6. Development of criteria for appropriate monitoring strategies.
7. Provision of scientific recommendations and a knowledge base for best practices for shale gas development with direct application and relevance to the provision of consistent regulation.

At the core of the project was modelling six focused scenarios, the scenarios are presented in an image accompanying this text. These scenarios formed the focus of the investigation, data collection, modelling effort, monitoring investigation and mitigation strategies.One of the key aspects of FRACRISK was to develop a user-friendly software platform for risk analysis assessment in relation to Shale Gas operations (Development and Production), SG-RBCA. SG-RBCA aims at providing a technically defensible, consistent and objective risk assessment and decision-making framework for operations of shale gas hydraulic fracturing. For implementation in the SG-RBCA platform, we managed to establish a work flow based on advanced forward models which were used to construct surrogate models to reproduce response surfaces of defined output quantities. FracRisk has addressed needs for monitoring and mitigation associated with key events that can potentially arise from shale gas production and wastewater injection. We have reviewed techniques suitable for geophysical monitoring in shale gas, and evaluated enhancement potential of seismic techniques.
FracRisk reviewed legislation and regulatory practices of those member states with significant shale-gas reserves (United Kingdom, France, Germany, Spain, Poland, Austria, Hungary and Romania). The main focus of the review has been on how existing legislation recognizes and seeks to control risks arising from uncertainties embedded in the shale-gas industry’s exploration and exploitation practices.
In terms of dissemination our aim was to make project results available to the scientific and general public, the FracRisk website (www.fracrisk.eu) contains details of all our dissemination activities including a widely available film.

Final results

FracRisk has developed the state of the art in all the key areas of its operation. Specifically the following aspects are highlighted as being beyond the state of the art.
• Assessment of geological data from 7 key shale gas basins across the EU and inclusion of data from America, analysis using a Hydro-Geo-Chemo-Mechanical facies approach
• The use of the GREAT cell at the university of Edinburgh to frac large scale samples in the laboratory under representative reservoir conditions
• Developed first of its kind FEP database for risks associated with shale gas exploitation
• Extending the capabilities of open-source numerical simulators process-oriented tools to illustrate the migration of possible hazardous materials along the flow path
• FracRisk has developed develop a user-friendly software platform for risk analysis assessment in relation to Shale Gas operations (Development and Production), SG-RBCA.
• Development of a new statistical models for the interpretation of hydrogeological properties exhibiting non-Gaussian behaviour
• Implementing of methodology to generate conditional realizations of environmental variables to be employed in numerical Monte Carlo analyses for environmental risk assessment.
• Quantification of uncertainty in the presence of diverse competing model alternatives through the establishment of an approach to rank models and estimate the relative degree of likelihood of each model.
• Development of a computationally efficient data-assimilation and uncertainty quantification framework, keyed to the characterization of dynamically evolving plumes of dissolved chemicals in heterogeneous aquifers
• Documented the serious failings of the existing process models of hydraulic fracturing, and used energy budgets to define the limits of what is physically possible.
• Shown that proppant-free frac-technique as is applied in petrothermal formations (HDR/EGS-systems) has a good chance of success also in shale-gas formations.
• FracRisk has provided a Legislation and regulatory practices review of those member states with significant shale-gas reserves (United Kingdom, France, Germany, Spain, Poland, Austria, Hungary and Romania )
• FracRisk provided a best practises document of scientific recommendations for best practices to minimise the environmental footprint of shale gas extraction.

Website & more info

More info: http://www.fracrisk.eu.