Detection and Simultaneous Localization of Microseismicity in DAS Data using a 2D Template Matching Approach

Subsurface fluid operations, including hydraulic fracturing, enhanced geothermal systems, and carbon capture and storage, typically induce microseismic events that can be used to evaluate the treatment’s success. In recent years, distributed acoustic sensing (DAS) has proved to be a cost-effective and long-lasting alternative to monitoring using borehole geophones. Although DAS maps the seismic wave field spatially much better, it shows a lower signal-to-noise ratio and produces higher volumes of data. To exploit the advantages of DAS as well as to compensate for the disadvantages due to the lower SNR, we propose a 2-dimensional template-matching approach for detection and localization in the continuous data. We apply this to seismicity induced at the hydraulic fracturing test site 2, recorded by one vertical and one horizontal fiber. Our approach also detects small-magnitude events reliably that are barely visible in the data. Due to the special fiber geometry of the data set used, the detected events can be localized directly without the need for additional manual picking. This is even possible for weak events that show no visible P-wave arrivals.