Thermal Attenuation and Lag Time in Fractured Rock: Theory and Field Measurements From Joint Heat and Solute Tracer Tests

摘要: The modelling and prediction of heat transfer in fractured media is particularly challenging as hydraulic transport properties depend on a multiscale structure that difficult to resolve. In addition advection dispersion, also impacted by thermal attenuation lag time, which results from fracture‐matrix exchanges. Here we derive analytical expressions for time coefficient media, quantify the effect fracture geometry these key factors. We use developed interpret single‐well tracer tests performed crystalline rock aquifer at experimental site Ploemeur (H+ observatory network). Thermal breakthrough was monitored with Fiber‐Optic Distributed Temperature Sensing (FO‐DTS), allows temperature monitoring high spatial temporal resolution. observed response departs conventional parallel plate model but consistent channel representing highly channelized flow. These findings, point strong reduction exchange flow channeling, show impact recovery geothermal systems. This study highlights advantages conduct both solute infer aperture geometry.