USING DISTRIBUTED TEMPERATURE SENSING (DTS) TO CHARACTERIZE FLOW IN A SHALLOW GEOTHERMAL WELL

In early 2010, New Mexico Tech completed a shallow (1102 ft) geothermal well that taps into the Socorro geothermal system near Woods Tunnel, 2.2 miles west of its campus in Socorro, NM. The well is intended to be used as part of a district geothermal heating system and to reduce the carbon footprint of the university by up to 6000 metric tons of CO₂ per year. As part of the characterization efforts for the well, chemical analyses, discharge estimates, and temperature profile measurements were performed. We have also installed a fiber optic cable downhole as part of a Raman-spectra distributed temperature sensing (DTS) installation. This method allows continuous temperature readings with 1 m spatial resolution and 1 min temporal resolution in both a static or dynamic environment. The DTS method provides dynamic temperature profiles as the well is pumped and perturbed from equilibrium. This allows us to identify the locations of conductive fractures during pumping. It also provides an independent check of more traditional static temperature profiling methods.