Distributed Temperature Sensing as a down-hole tool in hydrogeology
Distributed Temperature Sensing (DTS) technology enables down-hole temperature monitoring to study hydrogeological processes at unprecedentedly high frequency and spatial resolution. DTS has been widely applied in passive mode in site investigations of groundwater ow, in-well flow, and subsurface thermal property estimation. However, recent years have seen the further development of the use of DTS in an active mode (A-DTS) for which heat sources are deployed. A suite of recent studies using A-DTS down-hole in hydrogeological investigations illustrate the wide range of different approaches and creativity in designing methodologies. The purpose of this review is to outline and discuss the various applications and limitations of DTS in down-hole investigations for hydrogeological conditions and aquifer geological properties. To this end, we rst review examples where passive DTS has been used to study hydrogeology via down-hole applications. Secondly, we discuss and categorize current A-DTS borehole methods into three types. These are thermal advection tests, hybrid cable ow logging, and heat pulse tests. We explore the various options with regards to cable installation, heating approach, duration, and spatial extent in order to improve their applicability in a range of settings. These determine the extent to which each method is sensitive to thermal properties, vertical in well ow, or natural gradient ow. Our review conrms that the application of DTS has significant advantages over discrete point temperature measurements, particularly in deep wells, and highlights the potential for further method developments in conjunction with other emerging ber optic based sensors such as Distributed Acoustic Sensing.
V.F. Bense1, T. Read2, O. Bour3, T. Le Borgne3, T. Coleman4, S. Krause5,
A. Chalari4, M. Mondanos4, F. Ciocca4, and J.S. Selker6
Download: WP3_Read – subsurface DTS
- Department of Environmental Sciences, Wageningen University, The Netherlands.
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
- Geosciences Rennes, University of Rennes 1, Rennes, France.
- Silixa Ltd, Elstree, Hertforsdshire, WD63SN, UK.
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
- Biological and Ecological Engineering, Oregon State University, Corvallis, Oregon, USA.