Repurposing Legacy Borehole for Microseismic Monitoring: Geothermal Case Study from Cornwall, UK

May 2023

Avalon Sciences is very pleased to be a co-author on a University of Bristol Paper, being presented this year at EAGE Vienna Annual Meeting.

This June ASL will be exhibiting at the EAGE annual conference in Vienna. In addition, we are proud to be co-authors on a University of Bristol poster paper, which explores the potential of repurposing legacy boreholes to provide cost-effective seismic monitoring using instruments deployed in a former geothermal well at Rosemanowes Borehole Test Facility, Cornwall, UK.

These 1km deep borehole geophones captured a range of induced and natural seismicity, which include relatively nearby events originating from the United Downs Deep Geothermal Power (UDDGP) project and near Constantine, Cornwall. The lower noise and attenuation levels experienced by the Geochain borehole array has significantly increased the detectability rates for both the induced UDDGP and the natural Constantine sequences. After implementing a template-matching method for each seismic sequence, we were able to identify more than three times the number of seismic events when compared with those reported in the BGS catalogue based on surface measurements alone. This larger dataset provides greater insight into induced and natural seismicity of the area, which is of significant value to future deep geothermal projects.

Figure Above: Cumulative number and magnitude (ML) of events from UDDGP (top) and Constantine (bottom) sequences recorded on the 02/08/2020 and 24/02/2023 respectively. Significantly more events have been detected in the borehole dataset than identified using the surface networks.

Summary abstract is free to view online, with EarthDoc subscribers able to access the full paper.