De-Risking Shallow Geothermal Energy Storage In Challenging Urban Environments

Abstract

In 2017 TNO and GFZ combined an accelerometer based high resolution surface seismic survey with a fiber optic based VSP survey. The needed to take place on a narrow piece of land in a challenging, noisy urban environment. The objective was to demonstrate the possibility to acquire a cost-effective high resolution seismic image of the shallow subsurface to de-risk aquifer thermal energy storage (ATES) in an urban environment. What we expect to be a typical setting for these systems. The demonstration site was located in the capital of Germany, Berlin. The site was a very small piece of land, next to a busy road, not far from a busy railway and bus terminal. On the premises the Technical University of Berlin had drilled a well which it outfitted with fiber optic cables, to be used for various measurements (DTS but also acoustic). Over the course of two days TNO and GFZ performed seismic measurements from surface-based seismic sensors (3C accelerometers) and DAS measurements from the fiber optic cable inside the well. The (active) seismic source used was a small trailer mounted weight drop supplied by GFZ, but next to that passive seismic data was recorded as well. The modelled and recorded (and processed) results show that even under such challenging, noisy, urban conditions the shallow subsurface can be imaged, with seemingly adequate resolution to image aquifers relevant to geothermal operations like aquifer thermal energy storage. Hence this shows the capability of this approach in de-risking these types of geothermal activities in urban environments.

AAPG Datapages/Search and Discovery Article #90345 © 2018 AAPG European Region, Geothermal Cross Over Technology Workshop, Part II, Utrecht, The Netherlands, April 17-18, 2018