| Title | The Geothermal Potential of the Fractured Weardale Granite and Associated Aquifers of County Durham and Adjacent Areas Northern England |
|---|---|
| Authors | Jon GLUYAS, Charlotte ADAMS, Nadia NARAYAN, Cat HIRST |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | low enthalpy, geothermal, granite, fracture, permeability |
| Abstract | Though identified in the 1980s, the geothermal energy potential of the United Kingdom has still to be realised. Yet the possibility for supplying geothermal heat from a variety of deep, hot saline aquifers, shallow flooded mines and a suite of radiothermal granites is significant. Our calculations indicate that the resource to production potential based upon entirely supporting the UK heat demand is at least 100 years (Gluyas at al, 2018). In this paper we explore the potential of one region within the UK that could deliver geothermal heat via a combination of naturally fractured hot granite, deep saline aquifers, shallower karstified limestones and abandoned, flooded coal mines. The Weardale Granite in northern England's County Durham was first tested with a research borehole drilled in 1961 and more recently has been appraised with three further boreholes drilled by a consortium of partners led by Newcastle University and Durham University in 2004, 2010 and 2011. Well Eastgate 1 penetrated naturally fractured granite on the northern boundary of the Weardale Granite with a transmissivity of 4000 darcy m from an interval at 410 m at a temperature of 42°C. Eastgate 2 was drilled 700 m from the first well to test whether fluid flow could be obtained from within the granite. Although the well proved the high geothermal gradient in the area it did not flow water to surface. Science Central was drilled along the same bounding fault as Eastgate 1 and some 60 km further east within the centre of the city of Newcastle. It tested the flanking northern sediment wedge in what is known as the Northumberland Trough. It too recorded a high geothermal gradient but failed to flow, possibly due to loss of permeability along the fault zone targeted. The geothermal signature from the produced water at Eastgate 1 indicates that the water equilibrated at rock of at least 100°C. Work continues in an effort to understand the architecture of the productive and non-productive reservoir systems in the area. |