2017- What a year for SHEER!

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1 Issue 07, December 2017 Welcome to the seventh SHEER newsletter. The aim of this Horizon 2020 project is to develop best practices aimed at assessing the impacts and mitigating the environmental footprint of shale gas extraction and exploration What a year for SHEER! This year, the overall awareness, dissemination and publication output of the projects research has grown from strength to strength. The numbers visiting our online platforms such as Linked In, Twitter and Facebook have significantly grown, as have the number of reads of the material on ResearchGate (which has now reached over 500 reads!). The growing interest in the SHEER project is no doubt a result of all the hard work being undertaken by the participants. Over 10 papers on SHEER related research have been published this year and over 25 conference abstracts have been generated through our highly active research team presenting the projects work both near and far (i.e. from Austria (EGU) to Japan (IAG-IASPEI)). For further details and DOI s check out the projects group page on ResearchGate and/or the SHEER website. Another highlight from the year for the SHEER project was the stakeholder conference held in Blackpool in June. The event proved quite a success with the attendance of over 100 people and has been an important step in growing the projects awareness and engagement with stakeholders which again has also had a significant impact on driving up an interest in the project. Over the past six months and as we head into the final stages of the project, work on the SHEER project is focusing hard on the completion of several key deliverables and related reports. Most of these are publically available on the SHEER website and will continue to be uploaded when complete, till then, watch this space and in recognition of all the hard work done well done, to everyone on the SHEER team for all of your efforts this year! Oh, and have a Merry Christmas and a Happy New Year! In This Issue Main findings from WP5.2 - Wysin Site Groundwater Monitoring Small scale hydraulic fracturing experiment at Äspö Hard Rock Laboratory (Sweden): characterization of hydraulic fracture growth. Seismic monitoring with near-surface arrays SHEER Conference and Event Participation New Publications Latest Project Developments SHEER Participation in the M4ShaleGas Final Conference SHEER Task 4.2 Summary Presentation at AGIS/ESC This project has received funding from the European Union s Horizon 2020 research and innovation programme under grant agreement No

2 Main findings from WP5.2 - Wysin Site Groundwater Monitoring By Dr Catherine Isherwood (RSKW), Dr Nelly Montcoudiol (University of Glasgow) and the WP5.2 team Impacts of shale gas activities on groundwater resources Earthquakes of magnitude above 2.3 (Wang & Manga, 2010) or induced seismic events of high magnitude (Wang et al., 2017) have been known to trigger changes in groundwater levels, and potentially in temperature and chemistry. At Wysin, no changes in groundwater levels were observed after the two induced-seismic events identified in WP4. The main reasons for the absence of short-term changes are: (1) the groundwater monitoring was designed to capture medium-term changes (Δt = 15 min between measurements, precision of instruments); (2) low magnitude of the detected events although the epicentre is nearby; and (3) semi-confined aquifer behaviour (Montcoudiol et al., 2017). Apart from systematic changes related to sampling activities (Figure 1), groundwater temperature and electrical conductivity has been relatively constant during the entire monitoring period except in GW4. A significant increase in conductivity was observed between the sampling visits in April and June 2017 and again between the June and August 2017 visits (Figure 1). As soon as the pump was started for sampling, the conductivity decreased and returned to background levels within 10 minutes. As a result, the cause of these conductivity increases could not be identified by sample analysis. This behaviour suggests that these changes are the result of local contamination in the vicinity of the well rather than wide-spread contamination and are not related to the activities conducted at the shale gas pad. Reliable sampling and analysis of dissolved methane remains a challenge. Methane concentrations in the aquifer are around or below 10 µg/l, except in GW3 where they are about µg/l. δ13c (Carbon 13) isotope signatures range from -80/-70 to -50/-40. The spatial variability in methane concentration and carbon isotope signature is attributed to the heterogeneity of the Quaternary sediments (with the presence of peat locally) and the existence of different metabolic pathways for methane. These have not been identified yet but all the data point towards a biogenic origin for the methane sampled in GW3. According to published literature (e.g. Hammond, 2016; Osborn et al., 2011), the main risk is the migration of fugitive methane to the aquifer. The fate of methane once it dissolves in the shallow groundwater, and the chemical changes to be expected, are the object of on-going geochemical modelling. Assuming conservative behaviour of dissolved species, preliminary results from numerical transport modelling show that a brine leakage rate of 0.1 m3/d would trigger significant concentration changes in GW4 for barium, strontium, chloride and, to a lesser extent, sodium and bromide. Additional work is required regarding the use of modelling as a tool to anticipate changes in the aquifer and identify key parameters on which on-going monitoring should focus. Figure 1 Specific conductivity in GW4 from continuous water quality monitoring. Shaded areas represent the fracking periods. Dotted lines identify sampling visits. SHEER Newsletter Issue 07, December 2017

3 Recommendations The key recommendations from the study fall into three categories. Groundwater chemistry Inclusion of inorganic chemical species within the monitoring suite is important. These are considered to be good markers for groundwater monitoring as they can provide a useful proxy to warn of contamination. This is particularly the case with conservative species such as chloride, bromide and lithium, or general markers such as electrical conductivity. Parameters such as these can be used as an early-warning signal for potential contamination from a fracking site. Methane sampling Dissolved methane is considered to be a key indicator species for shale gas monitoring. However, the sampling and analysis of dissolved methane and related hydrocarbon gases is not a straightforward process. Modelling Hydrogeological and geochemical modelling can provide valuable tools with which to assess potential impacts to groundwater from operations, such as shale gas exploitation, that have the potential to affect the groundwater resource. It is important to include a broad suite of determinands within the baseline monitoring in order to fully characterise the geochemistry of the site. Once this has been undertaken, geochemical modelling can help to identify species of particular relevance to the site being studied and to determine potential contaminant trends to inform ongoing monitoring. All modelling relies on a robust dataset for the input and calibration process. A strong working relationship between the site operator and the monitoring partners is important to enable appropriate data sharing. For the modelling processes, these include subsurface data relating to the geology and geological structures as well as information concerning the frac fluid and flowback fluid compositions. References Hammond, P.A., The relationship between methane migration and shale-gas well operations near Dimock, Pennsylvania, USA. Hydrogeology Journal 24: Montcoudiol, N., Isherwood, C., Gunning, A., Kelly, T. & Younger, P. L., Shale gas impacts on groundwater resources: Understanding the behavior of a shallow aquifer around a fracking site in Poland. Energy Procedia 125: Figure 2 One of the methane sampling techniques used. Photo courtesy of Olga Lipińska (PGI). A number of different sampling and analysis techniques were tested (Figure 2), but the variability in the results indicates that a fully satisfactory solution has not yet been identified. Most commercial laboratories do not have the facilities to analyse for dissolved hydrocarbon gases, which adds an extra level of complexity to the problem. SHEER Newsletter Issue 07, December 2017 Osborn, S.G., Vengosh, A., Warner, N.R., & Jackson, R.B., Methane contamination of drinking water accompanying gaswell drilling and hydraulic fracturing. Proceedings of the National Academy of Sciences of the United States of America; 108: Wang, C.-Y. & Manga, M., Hydrologic responses to earthquakes and a general metric. Geofluids 10: Wang, C.-Y., Manga, M., Shirzaei, M., Weingarten, M. & Wang, L. P., Induced seismicity in Oklahoma affects shallow groundwater. Seismological Research Letters 88:

4 Small scale hydraulic fracturing experiment at Äspö Hard Rock Laboratory (Sweden): characterization of hydraulic fracture growth. By José Ángel López Comino, Simone Cesca and Arno Zang (GFZ-Potsdam) An understanding of the initiation and growth of induced fractures by fluid injection to estimate the size, orientation and potential geometries of rupture, may be inferred from the migration of microseismicity. In this regard, in situ rock fracture experiments conducted at underground research laboratories provide the ideal conditions to improve the characterization of hydraulic fracture growth. A very interesting and recent smallscale induced seismicity case is the one reported after an in situ hydraulic fracturing experiment that took place 410 m below surface in the Äspö Hard Rock Laboratory (Sweden). The experiment aimed to compare hydraulic fracturing growth and induced Acoustic Emission (AE) activity under controlled conditions for different fluid injection schemes: continuous versus progressive fluid injection and dynamic pulse hydraulic fracturing (Zang et al., 2017). AE events, with magnitudes well below zero and produced by cm- to dm-scale tensile cracks were recorded in continuous mode by a near field network composed of 11 AE sensors (Figure 1). These piezoelectric sensors are highly sensitive in the frequency range 1 to 100 khz, but sampling rates were extended to 1 MHz. Six hydraulic fracturing simulations were performed using three different injection schemes into a borehole 28 m long. The most significant seismic activity was recorded during the conventional, continuous water injection experiment for Hydraulic Fracture 2 (HF2) involving a maximum volume of 30 litres for fluid injection. Figure 1. a) Test site for hydraulic fracturing in an experimental tunnel of Äspö Hard Rock Laboratory, Sweden. b) Sensors are employed in the near-field: a blue line indicates the hydraulic testing borehole, the blue star identifies the fluid injection segment corresponding to the HF2 experiment (López-Comino et al., 2017). SHEER Newsletter Issue 07, December 2017 P a g e 4

5 Figure 2. Small temporal scale fracture growth is analysed for the propagation of the rupture during HF2 - Refracturing stage 5. a) Red dots identify different AE detection. AE magnitude (left ordinate), injection pressure and flow rate (right ordinate) are shown. Dashed grey lines indicate different temporal divisions for the detections. b) Locations of the AE events for the temporal divisions in a) showing the Gaussian kernel density where red denotes higher density of AEs and blue regions with few events. We also show the location of the fluid injection point (white star) and the hydraulic fracturing borehole (black line). AE activity migration reveals different rupture directions during the HF experiment. Figure elaborated after López-Comino et al., (2017). Waveform stacking and coherence analysis techniques are adapted to use with massive datasets with very high sampling rates (1 MHz) from HF2. An unsupervised automated full waveform detector is applied to the continuous dataset increasing the size of the AE catalogue by a factor of ~40, with more than 4000 AEs detected, against 102 AEs based on triggered recordings. The larger and more complete AE catalogue allows a more robust analysis of the frequency-magnitude distribution, which has revealed important new results implying high b-values of 2.4. The magnitude of completeness is also estimated at approximately MAE 1.1 and ranged between 0.77 and These results suggest some modifications to McGarr's empirical relation, where the cumulative injected volume controls the maximum magnitude of fluid injection induced seismicity. AE locations are furthermore refined using a relative, master-event location approach. The accurate locations and characterization of these events illuminate the main rupture area, describing the geometry of the rupture plane and observed seismicity migrations for different hydraulic fracture stages (Figure 2). Hydraulic fracture growth is then characterized by mapping the spatiotemporal evolution of AE hypocentres. The AE activity is spatially clustered in a prolate ellipsoid and an asymmetric rupture process related to the fracturing borehole is clearly exhibited. AE events migrate upwards covering the depth interval between 404 and 414 m. After completing each injection and reinjection phase, the AE activity decreases and appears located in the same area of the initial fracture phase, suggesting a crack-closing effect. These results have been recently published in Rock Mechanics and Rock Engineering (López-Comino et al., 2017). References: López-Comino, J. A., Cesca, S., Heimann, S., Grigoli, F., Milkereit, C., Dahm, T. and Zang, A. (2017). Characterization of hydraulic fractures growth during the Äspö Hard Rock Laboratory experiment (Sweden). Rock Mechanics and Rock Engineering, 50, 11, p Zang, A., Stephansson, O., Stenberg, L., Plenkers, K., Milkereit, C., Kwiatek, G., Dresen, G., Schill, E., Zimmermann, G., Dahm, T. and Weber, M. (2017). Hydraulic fracture monitoring in hard rock at 410 m depth with an advanced fluid-injection protocol and extensive sensor array. Geophys. J. Int., 208(2): SHEER Newsletter Issue 07, December 2017 P a g e 5

6 Seismic monitoring with near-surface arrays By Elmer Ruigrok (KNMI), Dorit Koenitz (KNMI) and Bernard Dost (KNMI) Shale gas is present over large basins in Europe (EIA, 2015), e.g. the Paris basin covers an area of over 100,000 km 2. If wide spread shale gas development took place, many operations could be in close proximity to each other, both in time and space. To monitor such wide-spread subsurface perturbations, it would become impractical and uneconomical to design and deploy a network for each individual operation. Instead, a backbone network should be put in place that covers a large area of anticipated operations. In the north of the Netherlands, such a network was constructed for monitoring induced seismicity from a string of gas fields. After extensive testing, a standard station design was chosen with an accelerometer at the Earth's surface and geophones at 50, 100, 150 and 200 m depth (Dost et al., 2017). In the following, we describe considerations for employing a network of such near-surface vertical arrays (VAs). levels of cultural seismic noise. Another cause is that waves induced in the basin remain partly trapped in the unconsolidated sediments, due to a high stiffness contrast with the underlying rock. A solution to the high-noise problem is to place the sensors below the surface. Placing sensors at a large depth, close to a potential source, would be optimal with respect to signal-to-noise, but would be very costly. Moreover, the sensors would add little to the goal of obtaining regional monitoring coverage. A pragmatic solution to this problem is the use of VAs. Given soft-soil conditions, they are easy to construct and yield strong noise reduction (Fig. 1). Going deeper than 200 m brings relatively little gain for the extra costs involved, because of the limited depth penetration of the surface-wave noise, for the frequency band of interest. Further noise reduction can be achieved by computing an enhanced seismogram over all 5 depth levels (Ruigrok et al, 2016). 2. Phase identification Fig 1 Power spectrum density (PSD) of a one-day verticalcomponent recording at station NL.G40. The noise reduces in power from the Earth s surface (blue line) to 200 m depth (orange line). 1. Noise suppression The issue of noise may be severe in deltaic areas where many potential shale gas sites are located. Deltaic areas are densely populated and have high Detection of seismicity is mainly done using the deepest geophone in the VAs, which has most favorable noise conditions (Fig. 1). In order to locate the earthquake, the different arrivals need to be interpreted and their timing needs to be picked. An erroneous interpretation would map into a location error; using all depth levels contribute to a sensible interpretation. Fig. 2(a) shows a recording for which it is easy to identify the direct P-wave arrival. The interpretation of the direct S-wave arrival is ambiguous. Fig. 2(b) shows the recording over the entire borehole. With help of apparent propagation velocities over the array, it is much easier to interpret the different arrivals. The first arrival can clearly be attributed to the direct P-wave (red line). The second marked arrival (green line) also has a P-wave velocity and is interpreted as an SP conversion. The third marked arrival (blue line) propagates much slower over the top 200 m and is interpreted as the direct S-wave arrival. SHEER Newsletter Issue 07, December 2017 P a g e 6

7 Fig 2 (a) Induced event recorded at 200 m depth. (b) Same event recorded over all depth levels of station NL.G41 with different arrivals marked. 3. Near-surface characterization Something that was not considered in advance, but turned out to be very useful, is the estimation of near-surface parameters from the recordings over the VAs. During installation of the VAs samples can be taken of the lithology. After installation, seismic velocities and anelastic loss factor can be estimated from the seismic recordings over the array. These parameters play an important role in the hazard assessment. They can be used, e.g., to identify lowvelocity layers that lead to amplification of waves. In Hofman et al. (2017) seismic velocities were estimated for the Groningen seismic network. Fig. 3 shows an example of an estimated near-surface response and the resulting S-wave and P-wave velocity profiles. References Dost, B., Ruigrok E. & Spetzler, J. (2017). Development of probabilistic seismic hazard assessment for the Groningen gas field. Netherlands Journal of Geosciences, doi: /njg EIA: U.S. Energy Information Administration (2015). World Shale Resource Assessments. Retrieved from Hofman, L.J., E. Ruigrok, B. Dost and H. Paulssen, 2017, A shallow velocity model for the Groningen area in the Netherlands, Journal of Geophysical Research: Solid Earth, 122, , doi: /2017jb Ruigrok, E., Paulssen H. & Dost B. (2016). Enhanced seismograms from borehole arrays. ESC: , European Seismological Commission 35th General Assembly, September 4-10, Trieste, Italy. Fig 3 : (a) S-wave response over NL.G41, estimated with seismic interferometry. (b) the S-wave velocity profile extracted from (a). (c) The analogously estimated P-wave velocity profile. SHEER Newsletter Issue 07, December 2017 P a g e 7

8 Shale Gas Exploration and Exploitation Induced Risks SHEER Participation in M4ShaleGas Final Conference the By Kostas Leptokaropoulos On October 18th and 19th, 2017, the M4ShaleGas final conference took place in Kraków, Poland. M4ShaleGas is a sister project to SHEER, funded within the same Horizon 2020 proposal, together with FracRisk and shalexenvironment. In order to enhance the interaction and cooperation among the projects, SHEER was represented in the M4ShaleGas final conference by Konstantinos Leptokaropoulos, Szymon Cielesta and Wojciech Białoń, from IG-PAS. The Conference was concentrated on the environmental impacts of Shale Gas exploitation and public concern issues. Extended statistics and numerical data (both reviewed and conducted) were presented. The SHEER representatives participated with a poster presentation and a short oral summary of SHEER project by Kostas Leptokaropoulos. They particularly pointed out the data base structure, the scientific results and the dissemination of the SHEER project research along with the open access policy of all publications and most of the deliverables. Several participants showed their interest for the poster. Most of their questions regarded data gathered within the project i.e. areas studied, pollutants measured (in case of air and water quality) and baseline/background measurements. SHEER Task 4.2 Summary and Results Presentation in AGIS/ESC Workshop By Kostas Leptokaropoulos On November 22nd and 23rd, 2017, the AGIS/ESC workshop for Induced Seismicity and Modelling Approaches took place in Hannover, Germany. Over 70 participants from many companies, institutions and universities from Germany, The Netherlands, Poland and Switzerland attended the workshop. A total of about 30 oral presentations were performed along with a short poster teaser. Kostas Leptokaropoulos from IG-PAS, represented the SHEER Project and in particular WP4. He performed a 20-minute presentation summarizing the main findings of the research conducted by the IG-PAS team under the framework of Task4.2 Statistical description of the induced seismic processes and assessment of relationship with technological/ operational parameters. Discussion with other participants and exchange of ideas and results took place during both days of the workshop. Two posters (titles below) were also presented at the AGIS/ESC workshop by José Ángel LópezComino: López-Comino, J. A., Cesca, S., Heimann, S., Niemz, P., Grigoli, F., Milkereit, C., Dahm, T. and Zang, A. (2017). Locating, characterizing and clustering of acoustic emissions from a hydraulic fracturing experiment at Äspö (Sweden) López-Comino, J. A., Cesca, S., Heimann, S., Dahm, T. and Lasocki, S. (2017). Induced seismicity response by hydraulic fracturing at the Wysin site (Poland). SHEER Newsletter Issue 07, December 2017 P a g e 8

9 SHEER Participation at other meetings and events On the 1 st September and 5 th December work on the SHEER project was presented by Tom Kelly (of RSKW) at both the Early Career Hydrogeologists Conference at the University of Strathclyde in Glasgow and at the SGG / CSRG poster competition in Glasgow respectively. Tom s poster (see image right) was entitled Groundwater Risks in Shale Gas Operations. On September 8th Paolo Capuano, Stanislaw Lasocki and Andrew Gunning participated to the H2020 Shale gas projects clustering workshop in Brussels, organized by INEA. On the 26th September, Glenda Jones (Keele University) discussed the SHEER project and website and distributed project leaflets and newsletters at Keele s Freshers week marketing event. Dr Catherine Isherwood (left), RSKW, presented a brief overview of the SHEER as a case study for fracking at the Geological Society Careers Day in Edinburgh on the 22 nd November. New Publications AlexanderGarcia-Aristizabal, Paolo Capuano, Raffaella Russo, Paolo Gasparini. (2017) Multi-hazard risk pathway scenarios associated with unconventional gas development: Identification and challenges for their assessment. Energy Procedia 125: /j.egypro Dost, B., E. Ruigrok, and J. Spetzler. (2017) "Development of Probabilistic Seismic Hazard Assessment for the Groningen Gas Field." Netherlands Journal of Geosciences. doi: /njg Hofman, L. J., E. Ruigrok, B. Dost, and H. Paulssen. (2017) "A Shallow Velocity Model for the Groningen Area in the Netherlands," Journal of Geophysical Research. B, Solid Earth 122 (10). doi: /2017jb Jagt, L., E. Ruigrok, and H. Paulssen. (2017) "Relocation of Clustered Earthquakes in the Groningen Gas Field." Netherlands Journal of Geosciences. doi: /njg Leptokaropoulos, Konstantinos, Monika Staszek, Stanisław Lasocki, Patricia Martínez-Garzón, and Grzegorz Kwiatek. (2018) "Evolution of Seismicity in Relation to Fluid Injection in the North-Western Part of the Geysers Geothermal Field." Geophysical Journal International 212 (2): doi: /gji/ggx481 Montcoudiol, Nelly, Catherine Isherwood, Andrew Gunning, Thomas Kelly, and Paul L. Younger. (2017) "Shale Gas Impacts on Groundwater Resources: Understanding the Behavior of a Shallow Aquifer Around a Fracking Site in Poland." Energy Procedia 125 (Supplement C): doi: /j.egypro SHEER Key Facts Project acronym: SHEER Project full title: Shale Gas Exploration and Exploitation Induced Risks Project duration: Funding Scheme: EU Horizon 2020 Project Partners: 8 partners from 6 countries AMRA (Italy), IGF PAS (Poland), Keele University (UK), GFZ Potsdam (Germany), KNMI (Netherlands), RSK W (UK), University of Glasgow (UK), University of Wyoming (USA) Project Coordinator Project Manager Communication and Dissemination Prof. Paolo Capuano AMRA S.c. a r.l. Via Nuova Agnano, Napoli, Italy pcapuano@unisa.it Alfonso Rossi Filangieri AMRA S.c. a r.l. Via Nuova Agnano, Napoli, Italy alfonso.rossifilangieri@na.infn.it Dr Glenda Jones Geography, Geology and the Environment, Keele University Keele, Staffordshire ST5 5BG United Kingdom g.m.jones@keele.ac.uk