3D deep geothermal reservoir imaging with wireline distributed acoustic sensing in two boreholes

Abstract. Geothermal exploration will help move towards a low-carbon economy and provide basis for green sustainable growth. The development of new practical, reliable methods geophysical characterization reservoir has the potential to facilitate broader application deep geothermal energy. At Groß Schönebeck in situ laboratory, unique vertical seismic profiling (VSP) dataset was recorded two 4.3 km boreholes using fibre-optic cables early 2017. experiment set-up consisted 61 vibrator points organized spiral pattern around well site ensure proper offset azimuth distribution target section. Data were processed standard workflow VSP. As result, detailed three-dimensional 0.75km×1km×4.5 image existing created Kirchhoff migration algorithm with restricted aperture. imaging resolved small-scale features essential future research site. Borehole data resolution up 16 m revealed depth variations Elbe sandstone horizon at 4.08–4.10 indications an unconformity area where we expect volcanic rocks. In addition, borehole complex interlaying numerous pinch-outs Upper Rotliegend section (3.8 4 depth) discovered. Thereby, demonstrate that wireline can significantly contribute by providing efficient method imaging.