Applying natural tracer technologies in the environmental monitoring of unconventional gas extraction

Lead Research Organisation: University of Edinburgh
Department Name: Sch of Geosciences

Abstract

It is clear from recent media coverage that there is significant public concern surrounding the exploitation of unconventional gas resources (shale gas and coal bed methane) in the UK. Many of these concerns relate to potential methane contamination of drinking water supplies in shallow aquifers. Developing a comprehensive strategy for monitoring any unconventional gas extraction in the UK will be paramount in reassuring the public that the extraction is being undertaken in a responsible and safe manner. This regulation must be based on strong scientific principles which need to be established prior to widespread unconventional gas extraction taking place.

This consortium project aims to use natural chemical components in groundwater and gases, to provide legally-defensible evidence in case of future allegations of methane contamination of groundwaters. This will be by obtaining chemical analyses of produced CBM and Shale Gas methane, shallow methane sources, and uncontaminated groundwater. Existing chemical analyses of baseline groundwater samples provide information on methane concentrations and the source of the water that the methane is contained in. However, they do not provide the unique fingerprint required to unequivocally determine the origin of methane.

We will collect samples of shale gas, CBM and produced waters and undertake measurements of the C and H stable isotopes, radiocarbon (14C) and noble gases (He Ne Ar Kr Xe) in the produced gases. These will allow the CBM and Shale Gas to be distinguished from other gas sources and provide a clear "fingerprint" for assessing groundwater contamination. We will also collect samples of baseline groundwaters and measure methane concentrations, C stable isotopes in the Dissolved Inorganic Carbon (DIC), H and O stable isotopes to provide a simple low-cost screening. Should the methane gas content of these groundwaters be found to be above 2 milligrams per litre we will separate the methane gas and measure the H and C stable isotope signature. This will allow us to determine the separate origins of both the groundwater and of the methane (which may be shallow bacterial or deep thermal source).

If sampling and analysis of groundwater during or after CBM or Shale Gas production shows that methane concentrations have increased, then analysis of the H, C, radiocarbon and noble gas components should be made on the groundwaters. This will allow the source of methane to be categorically resolved - is that methane of shallow bacterial origin, or from deep thermal sources which have previously been trapped at shallow depth, or is the increased methane an unambiguous addition of deep thermogenic methane from CBM or Shale Gas exploitation?

The proposed laboratory which will be setup by this consortium, along with the extra facilities for noble gas and radiocarbon analysis which will be provided with the match funding secured from the Scottish Government and the University of Edinburgh, will provide a greatly improved approach to high-quality assurance of environmental protection of groundwater. This facility will be unique in Europe and we will pursue application of the techniques at other European sites of unconventional gas extraction.

Action needs to be taken now, before widespread Shale Gas and CBM exploration and production activities commence in the UK. There is currently a one-off opportunity to collect and analyse uncontaminated baseline samples. We will publicise this research programme publicised to show the care with which Shale Gas and CBM regulation is being undertaken in the UK. This will provide public reassurance that lessons have been learnt from the negative unconventional gas experiences encountered in the USA and Australia.

Publications

10 25 50
 
Description New data has been obtained from a coal bed methane (CBM) field, Central Scotland. We have found that that the high concentration of helium is an ideal fingerprint for tracing fugitive gas migration to a shallow groundwater. The wells in the CBM field show variation in the noble gas signatures that can be attributed to differences in formation water pumping from the coal seams as the field has been explored for future commercial development. Dewatering the seams alters the gas/water ratio and the degree to which noble gases degas from the formation water. Additionally the helium and neon isotopic signatures exhibit a small but resolvable mantle input previously unseen onshore in the United Kingdom. We will outline the potential sources of this mantle input.
Exploitation Route Our findings shown that the noble gases in particular have the potential to be robust tracers of deep gas input into shallow aquifers, although further work to finalise these results and put them into context is still required.
Sectors Energy,Environment

 
Description They have been used to secure further funding in the monitoring of unconventional gas extraction by Total worth ~£1 million. This project has ascertained the origin and migration pathway of mantle derived CO2 gases that had contaminated an unconventional hydrocarbon play in Argentina, providing a robust estimate of the maximum amount of CO2 that could be encountered in that play. This is significant as any CO2 encountered would be expensive to remove, and would add to the greenhouse gas emissions of the project should it be vented to the atmosphere.
First Year Of Impact 2016
Sector Energy,Environment
 
Description EU Horizon 2020
Amount € 527,015 (EUR)
Funding ID RE8023 
Organisation European Commission 
Sector Public
Country European Union (EU)
Start 07/2015 
End 06/2018
 
Description Evaluation, Quantification and Identification of Pathways and Targets for the assessment of Shale Gas RISK (EQUIPT4RISK)
Amount £291,122 (GBP)
Funding ID NE/R018049/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 09/2018 
End 08/2022
 
Description New-Isotope Coupling and Classical tools: Applications to Reservoir and Exploration
Amount £956,000 (GBP)
Funding ID RB0398 
Organisation Total E & P 
Sector Private
Country United Kingdom
Start 08/2015 
End 07/2018
 
Description Noble gas geochemistry: CO2 source and fluid organization
Amount £13,959,800 (GBP)
Funding ID 4300003770 
Organisation Total E & P 
Sector Private
Country United Kingdom
Start 09/2018 
End 08/2022
 
Description Scottish Funding Council award scheme
Amount £60,000 (GBP)
Funding ID 242529545 
Organisation Government of Scotland 
Department Scottish Funding Council
Sector Public
Country United Kingdom
Start 04/2014 
End 01/2015
 
Description Scottish funding Council Standard Innovation Voucher Scheme
Amount £5,000 (GBP)
Organisation Government of Scotland 
Department Scottish Funding Council
Sector Public
Country United Kingdom
Start 12/2013 
End 03/2014
 
Description UKCCSRC flexible funding call 2018 project
Amount £195,000 (GBP)
Organisation UK Carbon Capture & Storage Research Centre 
Sector Academic/University
Country United Kingdom
Start 05/2020 
End 10/2021
 
Description University of Edinburgh IKT Fund
Amount £10,000 (GBP)
Funding ID IKTF 10P-12/0995 bi-monthly report 
Organisation University of Edinburgh 
Sector Academic/University
Country United Kingdom
Start 04/2013 
End 07/2014
 
Description Cuadrilla 
Organisation Cuadrilla Resources
Country United Kingdom 
Sector Private 
PI Contribution We have collected samples of produced gas from Cuadrilla's Elswick, Preese Hall and Balcombe oil and gas wells for radiocarbon, noble gas, stable carbon and oxygen analysis.
Collaborator Contribution Cuadrilla enabled sample collection by providing site access to the three wells and sites
Impact Samples have recently been analysed and will be presented in an manuscript which is currently under preparation.
Start Year 2013
 
Description Total E & P 
Organisation Total E & P
Country United Kingdom 
Sector Private 
PI Contribution The novel use of geochemical tracing tools in the research in this grant led to discussion with an interested contact within Total Exploration and Production. This led to the development of an industrial collaboration with the Scottish Universities Environmental Research Centre, firstly aimed at understanding the connectivity of a UK North Sea hydrocarbon discovery and then on understanding the origin of CO2 in unconventional gases in Argentina. This has recently been followed by a project aimed at applying geochemical tools to constrain the origin of elevated CO2 levels in offshore Brazilian hydrocarbon fields.
Collaborator Contribution New-ICCARE project: Total had realised that isotope coupling had become a powerful tool to constrain the origin of fluids and a robust means to determine the rates of fluid migration in academic studies. However, this had only been applied to large scale geological models, meaning that the existing techniques were unsuitable for inclusion in predictive reservoir models. The over-arching aim of the New-ICCARE project was to incorporate reservoir and thermodynamic modelling into the existing state of the art isotope coupling techniques. UoE scientists evaluated the role that noble gas isotope geochemistry can play in determining the origin of natural CO2-rich fluids contaminating an unconventional field where hydrocarbon production has been stimulated by hydraulic fracturing (fracking), and the development a new method to determine the static reservoir connectivity using noble gases within the Tormore hydrocarbon discovery of the UK North Sea. CO2 source and fluid organisation project: The pre-salt reservoirs of the offshore Brazilian and Angolan Atlantic margins are known to have a complex fluid history. They are composed of a mixture of hydrocarbon fluids and variable amounts of CO2. It is known that this CO2 has a predominantly magmatic source linked to rifting, associated transfer zones, or to mantle plumes. The timing of CO2 charge is dependent on its source and the duration of the related magmatism, which has an important impact on the ability for hydrocarbon fluids to enter reservoirs or spill from them, or be diluted with CO2. The UoE team provided an integration of noble gas tracing constrains to the reservoir fluid charging history (HC+CO2) with basin modelling. Selected samples from pre-salt reservoirs were analysed, and compared to existing fluid databases from the two margins. This showed that the CO2 was unequivocally from a deep mantle origin, allowing the identification of high risk areas where deep crustal faults related to the Atlantic opening intersected with shallow basin related faults.
Impact New-ICCARE Project Impact: The project delivered two significant outcomes. The first of these ascertained the origin and migration pathway of mantle derived CO2 gases that had contaminated an unconventional hydrocarbon play in Argentina, providing a robust estimate of the maximum amount of CO2 that could be encountered in that play. This is significant as any CO2 encountered would be expensive to remove, and would add to the greenhouse gas emissions of the project should it be vented to the atmosphere. The second outcome was a new means to determine static reservoir connectivity using a combination of noble gas isotope coupling and reactive flow modelling from exploration wells. Both of these outcomes have provided new knowledge to assist Total in the responsible exploitation energy resources from both regions. CO2 Source and Fluid Organisation Project Impact: The project has obtained an overview of the absolute charging time and precise origin of the CO2. This will allow the CO2 associated exploration risk for individual areas to be quantified, and will greatly assist in economic exploration of the provinces. This will translate into avoidance of accidental drilling into a high-CO2 accumulation, and as each well in the region costs ~€40M to drill and complete, significant cost savings to the operator are envisaged.
Start Year 2015
 
Description Goldschmidt 25th Conference - Oral presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Oral presentation: Tracing the migration and fate of CO2 in natural and CO2-EOR fields using noble gases, 25th Goldschmidt International Geochemistry Conference, Prague, Czech Republic, August 2015
Year(s) Of Engagement Activity 2015
URL http://goldschmidt.info/2015/uploads/abstracts/origPDFs/5333.pdf
 
Description Innerleithen Local Community Meeting on Fracking 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Invited Speaker at Innerleithen local community meeting on Fracking
Year(s) Of Engagement Activity 2015
 
Description Invited Speaker at Edinburgh Labour party meeting on Energy 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Policymakers/politicians
Results and Impact Invited Speaker at Edinburgh Labour party meeting on Energy, presented on Unconventional gas in the UK
Year(s) Of Engagement Activity 2015
 
Description Presentation at ChemEng day, Manchester, April 2014 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Academic researchers and industrial professionals at all levels working within research in chemical engineering and related sectors, particularly those based within the UK attended the ChemEng day at the University of Manchester. I presented a talk entitled 'Opportunities for Engineering Clean Fossil Fuels for a Decarbonised Future' talk which was attended by ~200 delegates. The talk was followed by a panel discussion and I was asked a number of questions on my research in the area.

The chair of the session, President of the IChemE, Geoffrey Maitland reported that my talk had been well received and had promoted discussion following the session.
Year(s) Of Engagement Activity 2014
URL http://www.gnomikos.com/CEDay2014/
 
Description Presentation at European Shale Gas and Oil Summit 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Invited Speaker: A cleaner option - UCG and CCS working in tandem, Manchester, UK, October 2015.
Year(s) Of Engagement Activity 2015
 
Description Presentation at European Shale Oil and Gas Summit in London 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact ghaggd

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Year(s) Of Engagement Activity 2014
 
Description UK failing to learn U.S. lessons on fracking waste water 
Form Of Engagement Activity Engagement focused website, blog or social media channel
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Media (as a channel to the public)
Results and Impact Blog post on Energy and Carbon site
Year(s) Of Engagement Activity 2016
URL http://energyandcarbon.com/uk-failing-lessons-fracking-waste-water/