EXCALIBUR - Example of Coherent Amplified Light for In-Borehole Microseismic Recording

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With the global drive to increase the proportion of energy generation through renewable sources, geothermal energy has attracted recent attention for its ability to produce both heat and electrical energy without a dependence on environmental factors such as wind or solar output. A geothermal power station extracts heat deep from within the Earth's crust where areas of rock typically reach 240°C.Creating geothermal power stations in "hot rock" areas requires drilling boreholes into the Earth's crust and creating pathways for water to flow through hot bedrock. This drilling activity requires careful monitoring to ensure the intended water pathways are correctly created and to satisfy strict environmental monitoring (especially in the UK) for micro-seismic activity to ensure that larger seismic events are not induced by this deep drilling. Vertical Seismic Profiling (VSP) with micro-seismic sensors is used to achieve this monitoring in addition to monitoring the ongoing health of a geothermal station during its lifetime.Avalon Sciences Limited (ASL) is a world-leading manufacturer of VSP systems which have been used predominantly in the oil & gas industry for exploration for the past 35 years. With ASL's in-house research & development centre, innovation in sensor design has enabled reliable operation of their electronic and optical VSP systems at 200°C. However, these systems cannot survive for long in the excessively high temperature geothermal wells.In this project, ASL will develop a bespoke all-optical (no electronics) micro-seismic VSP prototype capable of operating up to 300°C for long-term micro-seismic monitoring for the geothermal energy industry.