Geothermal Monitoring – Providing the tools for the job!

April 2021

Avalon Sciences Ltd (ASL) is proud to be part of the instrumentation for the innovative Bedretto Underground Laboratory for Geoenergies, Switzerland.  Avalon seismic tools are rapidly becoming the preferred option for high resolution seismic characterisation and monitoring of Enhanced Geothermal Systems (EGS).

Avalon has enjoyed the position of market leader in the design and manufacture of borehole seismic tooling for decades.  During this time, we have provided tooling, services, expertise and training to thousands of operations and major players across the globe.  Whilst the majority of business has been within the oil and gas industry, ASL has also provided input to industry leading projects within other markets, including mining and geothermal energy.  The latter of these represents a paradigm shift in our market, one in which ASL is proud to be considered a world leading innovator.

As a result of ASL’s burgeoning reputation within the geothermal industry, we have recently been involved in several cutting-edge operations, including the Bedretto underground geothermal research project and the upcoming US Department of Energy backed FORGE research project.  This is largely due to the quality and reliability of our robust and industry leading tools, including our new passive fibreoptic systems, which are designed and engineered in-house by our experienced and dedicated engineering team.  Our high temperature and pressure ratings make them quite literally the ‘tools for the job’ in any geothermal operation.

Photo of the disused railway tunnel, in which the Bedretto Underground Lab is.

The Bedretto Underground Lab is halfway down a disused railway tunnel. One advantage of this tunnel as a lab is it allows an emergency exit either side of a collapse due to induced seismicity! Picture from Werner Siemens-Stiftun.

The Bedretto lab is running research and exploring techniques to try to make the most of deep geothermal without associated risks of induced seismicty.  In November 2020, Bedretto began its first full-scale stimulations, which are known to cause tiny levels of shaking (imperceptible without scientific measuring equipment), or “micro-earthquakes.” A stimulation involves creating a network of cracks in the granite by injecting a few tens of cubic metres of cold water through it. The goal being to locate in 3D space and in real time the foci of potentially tens of thousands of micro-tremors. Find out how these tremors occur!

Seismic Engineer deploying Avalon fibre cables into tunnel wall borehole.

Avalon plays its part!

By combining our new Borehole Optical Seismic System (BOSS™) with acoustic and pore-pressure sensors the client is able to monitor and record vibrations in the granite as the water is injected into sections of the borehole. This data helps to map out the rock’s permeability by revealing the fracture’s size, characteristics, quantity, direction and stress capabilities under different water pressures. Knowing to what extent the granite can be made ‘artificially permeable’ will inform whether a reservoir that stands up to geothermal extraction can actually be made.

Further details of the Bedretto Underground lab can be found at the BUL website.

BOSS™ is our latest innovation in entirely passive borehole seismic tooling, capable of operating at high continuous temperatures (200°C) and pressures (20,000psi) for long term deployments.  The fibreoptic system combined with rugged specifications means BOSS can be viewed as a life-of-field installation and is the ideal tool for geothermal monitoring under any conditions.

Let there be light!

Named after the goddess of light and healing waters, the ‘Sulis’ DAS interrogator is a high performance, rugged and compact distributed optical fibre sensor interrogator, which provides very high sensitivity distributed measurements of phase changes within standard optical fibres.  It can be deployed at up to 300°C and 30,000PSI and is suitable for operations in the harshest of conditions.  Sulis can be combined alongside our conventional Geochain™ or BOSS™ systems to realise a massive hybrid distributed seismic receiver through overburden with high resolution 3-component sensors throughout the reservoir, including distributed recording through the entirely of the wireline!

All of us at ASL recognise the immense and expanding potential of the geothermal industry, not just commercially but also as a crucial part of the ever pressing and increasingly significant drive towards global sustainability.  As such, our team are united in our commitment to ensuring we retain our position as the go-to designer, producer and innovator in cutting-edge, rugged and exceptional quality downhole geothermal tooling.

For more information on our products, services or research or any other inquiries, please contact us today at:, or call us on  +44 (0) 1458 270000.