A case study based assessment of potential cumulative impacts on groundwater from shale gas production in Northern England

The UK shale gas industry might see significant growth in the near future, with many energy companies already having gained approval and others in the stages of seeking approval for exploration. Exploratory boreholes have been in place in the Vale of Pickering, North Yorkshire, and the Fylde Basin, Lancashire, since 2013 and 2010 respectively. Since then, several other sites around the UK have been earmarked for future exploration. The current absence of producing shale gas wells within the UK means it is too early to assess any actual impact of these operations at the local, regional and national scale. However, international analogues may provide some indications based on areas elsewhere in the world where a shale gas industry is more developed (e.g. the Marcellus Shale, USA) albeit with obvious limitations due to differences in geology and setting. While regulation and compliance of shale gas operations varies between countries, the process and method of extraction and the environmental risks are comparable. The general requirements for water, drilling mud/fluids, hydraulic fracturing fluids (“frac fluids”) and the design of wells and well pads can all be extracted from an already mature international experience. However, the requirements in the UK will be modified by the regulatory requirements and restrictions that exist. There are ongoing discussions within the UK to determine whether shale gas is beneficial, economically viable and environmentally safe. In this report, the impact on land use, groundwater quality and water resources of one well in a selection of approved Petroleum Exploration and Development Licence (PEDL) areas will be considered, followed by an estimation of the cumulative impacts that may result from multiple extraction sites within these areas. The exercise will depend on ranges of input parameters informed by international analogues applied in a UK geo-environmental setting. To recognise the variability in parameters and uncertainty in UK industry development, a range of impact scenarios - low, moderate and high – have been considered

Environmental baseline characterisation and monitoring borehole GGB05, UK Geoenergy Observatory, Glasgow

This report and accompanying data release describe the ‘as-built’ borehole GGB05 at the UK Geoenergy Observatory in Glasgow, as well as summarising hydrogeological testing and an initial geological interpretation. Environmental characterisation and monitoring baseline borehole GGB05 at the UK Geoenergy Observatory in Glasgow is screened across a sandstone beneath rockhead, and thought to be around 5 m above recorded stoop and room mine workings in the Glasgow Upper coal. Initial hydrogeological indications from the test pumping suggest that borehole GGB05 is moderately yielding. There is a hydrogeological data logger installed in the borehole

Environmental baseline characterisation and monitoring borehole GGB04, UK Geoenergy Observatory, Glasgow

This report and accompanying data release describe the ‘as-built’ borehole GGB04 at the UK Geoenergy Observatory in Glasgow, as well as summarising hydrogeological testing and an initial geological interpretation. Environmental baseline characterisation and monitoring borehole GGB04 at the UK Geoenergy Observatory in Glasgow is screened across a sand and gravel unit in the upper part of the superficial deposits. Hydrogeological evidence from test pumping indicates that the borehole is very low yielding. There is a hydrogeological data logger installed in the borehole

UK Geoenergy Observatories Cheshire : hydraulic testing of TH0424 technical summary

This report details the schedule and results of hydraulic testing of the TH0424 ground investigation borehole at the UK Geoenergy Observatory (UKGeos) Cheshire borehole array, Thornton Science Park during October 2022. UKGeos aims to establish new centres for world-leading research into the subsurface environment, generating data and knowledge to inform responsible development of new subsurface technologies (https://www.ukgeos.ac.uk/). Observatories are currently being developed at Thornton Science Park (TSP) in Cheshire (near the villages of Thornton and Elton), and near the Cuningar Loop of the River Clyde, Glasgow. Hydraulic testing was conducted using a straddle packer system to allow for isolated testing through the entire length of the water column, and to isolate specific features of interest (e.g. fractures, low permeability zones etc.), employing step and constant rate pumping test methodologies to provide response data that can be applied to hydraulic property models. The isolation of specific zones also allowed for the opportunity to collect groundwater samples and hydrochemical parameters, providing a profile of hydrochemical composition. The straddle packer system allows characterisation of dominant flow paths within the borehole and thus will aid in informing the design of multilevel monitoring boreholes within the array. This report does not serve as an interpretation of the collected data (although some basic analysis is undertaken), but rather aims to provide context to the collected dataset that can be utilised by the wider scientific research community. Development of the site at the time of testing (drilling of boreholes in close proximity) resulted in sub-optimal conditions for hydraulic testing and thus some data have been impacted by these activities. Perturbations or deviations in data thought to arise from these activities have been highlighted where possible. Abstractions from the Thornton Science Park abstraction borehole c.350m from the UKGeos array is also known to be detected at TH0424 with the site sitting within the radius of influence. Abstraction events taking place during individual tests have been highlighted and the full record of abstractions for the testing period is available. Borehole information packs available from UKGeos also provide daily drillers borehole records to relate any potential impacts from drilling activities. Considering the above caveats, care should be taken when using the data obtained during hydraulic testing and it should only be used in context of local activities, events or works. This report accompanies the full data pack of hydraulic testing data and supplementary information available at https://doi.org/10.5285/f1ad3bf6-f32a-4895-9f5f-8fa95c158832

Data release and initial interpretation of test pumping of boreholes at the Glasgow UK Geoenergy Observatory

This report describes a programme of test pumping carried out on ten boreholes at the UK Geoenergy Observatory (Glasgow Observatory), Cuningar Loop in Rutherglen, Greater Glasgow in January and February 2020. It details the types of test undertaken, the datasets generated and how these datasets can best be used dependent on the data analysis being undertaken. Drawdown data for pumping boreholes and observation boreholes is presented in graphical form, together with an initial interpretation of test pumping results. The main objectives of the pumping tests were to obtain data regarding: the physical aquifer properties, in particular transmissivity, of the different hydrogeological zones at the Observatory; to investigate borehole efficiency; and to gather data on the connectivity between different hydrogeological zones. Successful step tests and five hour constant rate tests were carried out in all boreholes except GGB04 in the superficial deposits where a slug test was carried out instead due to the low yield. Time series data of water levels, temperature and conductivity were collected in the pumping and observation boreholes. The constant rate tests were analysed using Jacob’s approximation and Theis recovery methods to give a preliminary interpretation of the transmissivity. The drawdown curves were visually inspected to help identify borehole inefficiency and significant responses from observation boreholes to pumping. Transmissivity values for the superficial deposits are highly variable (0.04 and 225 m2/day), the two bedrock test pumping responses also gave very different results (2.6 and 580 m2/d), three boreholes in the Glasgow Upper mine workings give a consistent transmissivity estimate (950 – 1020 m2/d) and the two boreholes intersecting the Glasgow Main mine workings give transmissivity estimates of 2000 – 2100 m2/d. There is clear connectivity between the bedrock boreholes and the Glasgow Upper mine workings during pumping, with strong responses between boreholes from most pumping tests. There is also clear connectivity within the individual mine workings. There is also evidence of some connectivity between the Glasgow Main mine workings and the Glasgow Upper mine workings. There is an upward vertical hydraulic gradient at the Observatory, with rest water levels approximately 10 – 11 m relative to Ordnance Datum (OD) in the Glasgow Main mine workings; 9 – 10 m OD in the Glasgow Upper mine workings and bedrock boreholes, and 3 – 4.5 m OD in the superficial deposits. Temperature measurements from observation boreholes monitored throughout the testing period show that the groundwater in the deeper Glasgow Main mine workings is warmer than the shallower workings, bedrock or superficial deposits with a value generally 12.4 – 12.8 ºC. Temperatures in the Glasgow Upper mine workings and the overlying bedrock are broadly similar, 11.5 – 12 ºC, apart from GGA04. Specific electrical conductivity measurements from the mine workings and bedrock boreholes lie in the range 1350 - 1600 µScm-1 @25 ºC and are typical of measurements from water boreholes within mined Carboniferous rocks (MacDonald et al. 2017). The conductivity of the superficial deposits is high and variable at 1000 – 1400 µScm-1 @25 ºC, although within the range of those found in Glasgow (Ó Dochartaigh et al. 2018)

Method and key observations from constructing a mine water heat subsurface observatory in Glasgow UK

The UK Geoenergy Observatories project (UKGEOS) is developing a subsurface Observatory in Glasgow for research and innovation in mine water heat and heat storage. This report provides an overview of the timing and tasks adopted in borehole construction and initial testing. It has been subdivided into three stages: planning/feasibility, exploration and appraisal. The fourth delivery or development stage, which is to construct the above ground infrastructure for mine water circulation and thermal perturbation, is ongoing in 2021 and is not covered in this report. Land availability, prior land use and environmental protection were key constraints in establishment of the Observatory, as well as subsurface geological factors. These are likely common to many mine water heat projects. Observations made during construction of the Glasgow Observatory are summarised to help to de-risk future mine water projects. These include difficulties associated with completing boreholes through sands and gravels in superficial deposits, and the challenge of identifying the type and size of mine workings during drilling. A key learning was the value of using a downhole optical or acoustic camera to better understand the nature of mine workings prior to screen installation

GGC01 cored, seismic monitoring borehole – initial data release

Summary This report gives a short overview of information related to the initial data release for GGC01. The cored, seismic monitoring borehole GGC01 (BGS SOBI number NS66SW BJ 3754) was drilled between 19 November and 12 December 2018 producing a core of 102 mm diameter. The borehole was wireline logged in December 2018 and a string of 5 seismometers were installed in February 2019. Contributions to this report and the data acquired are as follows: Vanessa Starcher: Technical overview, wireline log data acquisition Kirsty Shorter: Fluid and geomicrobiology samples, tracer information, field measurements, photo metadata Hugh Barron: On-site core and data acquisition, initial geological interpretation Joel Burkin; Geomicrobiology samples, on site core management and initial geological interpretation Jack Elsome: Fluid and geomicrobiology samples Mark Fellgett: Wireline log data checking and documentation Andy Kingdon: Wireline log data checking and documentation Megan Barnett: Geomicrobiology samples Alison Monaghan: Coordinating initial data pack, initial geological interpretation IMPORTANT – Note that all borehole depths given in the initial data release are based on the drillers log dataset (excepting wireline data). Borehole depths will be subject to minor change once non-recovery intervals are assigned. Borehole and sample depths will be revised in the final borehole data pack so that core scans, wireline logs and borehole logs/samples are consistent

Drilling into mines for heat: geological synthesis of the UK Geoenergy Observatory in Glasgow and implications for mine water heat resources

Thermal energy from groundwater in abandoned, flooded, coal mines has the potential to make a significant contribution to decarbonisation of heat and Net-Zero carbon emissions. In Glasgow, UK, a subsurface observatory has been constructed for mine water heat and heat storage research. We synthesise geological and mine water resource findings from a four-year period of borehole planning, drilling, logging and testing. The heterogenous bedrock is typical of the Scottish Coal Measures Group, whereas superficial deposits are more sand- and gravel-dominated than prognosed. Mine water boreholes encountered workings in the Glasgow Upper, Glasgow Ell and Glasgow Main coal seams, proving water-filled voids, mine waste, fractured rock mass and intact coal pillars with high yields on initial hydrogeological testing. Whilst the depth and extent of mine workings delineated on mine abandonment plans proved accurate, metre-scale variability was expected and proved in the boreholes. A mine water reservoir classification established from the observatory boreholes highlights the resource potential in areas of total extraction, stowage, and stoop and room workings. Since their spatial extent is more extensive across the UK than shafts or roadways, increasing the mine water energy evidence base and reducing exploration risk in these types of legacy workings is important

UK Geoenergy Observatories Glasgow: GGC01 cored, seismic monitoring borehole – final data release

This report provides an overview of information contained in the final data release for the UK Geoenergy Observatories Glasgow borehole GGC01. This final data release supersedes the initial and intermediate data releases (Starcher et al. 2019; Kearsey et al. 2019). It includes additional information on core scan data and core-wireline depth integration. The cored, seismic monitoring borehole GGC01 (BGS SOBI number NS66SW BJ 3754, BGS ID 20650619) was drilled between 19 November and 12 December 2018 producing a core of 102 mm diameter. The borehole was wireline logged in December 2018 and a string of 5 seismometers were installed in February 2019. The core was transported to the National Geological Repository (NGR) at BGS Keyworth and was curated into 1 m core boxes. State-of-the-art core scanners have been used to collect along core datasets. This final data release includes optical images (whole core and slabbed core), radiographic images, MSCL-S (geophysical), NIR and XRF (mineralogical and chemical) core scan data. Also included in this final release is the material from the previous releases including sedimentary, discontinuity and engineering logs, wireline/geophysical downhole logs, drillers’ logs and sample information

UK Geoenergy Observatories Glasgow: GGC01 cored, seismic monitoring borehole – intermediate data release

This report gives an overview of information related to an intermediate data release of the borehole information pack for UK Geoenergy Observatories: Glasgow borehole GGC01. The cored, seismic monitoring borehole GGC01 (BGS SOBI number NS66SW BJ 3754, BGS ID 20650619) was drilled between 19 November and 12 December 2018 producing a core of 102 mm diameter. The borehole was wireline logged in December 2018 and a string of 5 seismometers were installed in February 2019. The core was transported to the National Geological Repository (NGR) at BGS Keyworth and was curated into 1 m core boxes. State-of-the-art core scanners are being used to collect radiographic, CT, optical images, geophysical log and XRF along core datasets. Optical images and radiographic images are included in the intermediate release. Also included are sedimentary, discontinuity and engineering log