Using Fibre-Optic DAS surveying to de-risk a shallow geothermal energy storage site in Brussels, Belgium

Europe is working hard to meet its first climate goals. With High Temperature Aquifer Thermal Energy Storage (HT-ATES) large quantities of green energy can be stored in the subsurface in the form of heat. It is important that a site is characterised well as leakage from the reservoir would degrade the efficiency of the system, and could also endanger potable water supplies. Seismic imaging is currently the method with highest resolution and the largest de-risking capability for geothermal projects. This study pursues the use of fibre-optic distributed acoustic sensing (FO-DAS) technology in seismic acquisition to improve the de-risking ability of seismic data in urban HT-ATES settings. In 2019 TNO and GSB combined a dense surface based high resolution seismic survey with a FO-DAS VSP survey on a potential ATES site in the city of Brussels, Belgium. Besides the technology demonstration, targets were aquifer + seal continuity and depth away from the well as well as acoustic velocity of the sediment overburden for H/V Spectral Ratio calibration. The intermediate result indicates that with FO-DAS it is possible to image the subsurface relatively easy, fast, at low cost and with low environmental impact, even in busy seismically noisy urban areas.

Abstract of an Oral Presentation or a Poster