Groundwater flow characterization in a fractured bedrock aquifer using active DTS tests in sealed boreholes

JOURNAL OF HYDROLOGY

卷:528

Article

Coleman, Thomas I.^1,2  Parker, Beth L.¹  Maldaner, Carlos H.¹  Mondanos, Michael J.² 

[1] Univ Guelph, Sch Engn, Ctr Appl Groundwater Res G360, Guelph, ON N1G 2W1, Canada

[2] Silixa Ltd, Elstree WD6 3SN, Herts, England

关键词: Fractured rock;    Groundwater flow;    Distributed temperature sensing;    Borehole sealing;   

DOI  :  10.1016/j.jhydrol.2015.06.061

来源: Elsevier

【 摘 要 】

In recent years, wireline temperature profiling methods have evolved to offer new insight into fractured rock hydrogeology. Important advances in wireline temperature logging in boreholes make use of active line source heating alone and then in combination with temporary borehole sealing with flexible impervious fabric liners to eliminate the effects of borehole cross-connection and recreate natural flow conditions. Here, a characterization technique was developed based on combining fiber optic distributed temperature sensing (DTS) with active heating within boreholes sealed with flexible borehole liners. DTS systems provide a temperature profiling method that offers significantly enhanced temporal resolution when compared with conventional wireline trolling-based techniques that obtain a temperature depth profile every few hours. The ability to rapidly and continuously collect temperature profiles can better our understanding of transient processes, allowing for improved identification of hydraulically active fractures and determination of relative rates of groundwater flow. The advantage of a sealed borehole environment for DTS-based investigations is demonstrated through a comparison of DTS data from open and lined conditions for the same borehole. Evidence for many depth-discrete active groundwater flow features under natural gradient conditions using active DTS heat pulse testing is presented along with high resolution geologic and geophysical logging and hydraulic datasets. Implications for field implementation are discussed. (C) 2015 Elsevier B.V. All rights reserved.

【 授权许可】

Free