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Distributed temperature sensing is known to provide sharp signals which are very efficient for mapping hydraulically active fractures in wellbores. High-resolution temperature sensing has specifically demonstrated its capacity to characterize very low flows in wellbores. But as sharp as they can be, temperature profiles are often difficult to decipher. The aim of the present work is to provide and to test the “Borehole Heat Budget Calculator” (BHB Calculator), which is implemented as a fast and easy to use tool for the quantitative analysis of depth-temperature profiles. The Calculator is suitable for most pumping and draining configurations, as the heat budget is generalized for modelling multidirectional flow systems within the same wellbore. The formatted worksheet allows the quick exploitation of temperature logs, and is applicable for the characterization of distributed fractures in long screened wellbores. Objectives of the heat modelling are to enhance the readability of complex depth-temperature data, as well as to quantify distribution of inflow intensities and temperatures with depth. The use of heat budget helps to clearly visualize how heat conduction and heat advection contributions are distributed along wellbores profiles. Calculations of inflow temperatures and their evolution through pumping duration is a prerequisite to infer about the nature of aquifer properties (i.e. conduits, distributed or discrete fractures, porous media), as well as to give insight information about the mapping of effective flow paths draining the aquifer. The efficiency and limitations of the BHB Calculator are being tested through high-resolution temperature logging, along with complementary flowmetering and televiewing logging in fractured aquifers located in the St-Lawrence Lowlands, Quebec, Canada.

Summary A new hydrogeologic model is developed for the Plateau de Saclay (20 km south-west of Paris, France), which covers an area of 74 km 2 . It is based on a 2D model of the Fontainebleau Sands aquifer, combined with a 1D model of the unsaturated zone, taking into account the spatial variability of the groundwater permeability field and the thickness of the unsaturated zone. The paper focuses on the estimation of a triplet of parameters (permeability, infiltration and effective porosity), based on transient flow simulations. First, the permeability is obtained by inversion of mean hydraulic head data for different values of infiltration. Then, infiltration and effective porosity are determined by using transient flow simulations and fitting the hydraulic head measurements at several piezometers over the 1970–2014 period. The infiltration is estimated at between 125 and 150 mm/yr, the mean permeability between 2 · 10 −5 and 6 · 10 −5 m/s, and the effective porosity between 20% and 30%. Furthermore, the role of the unsaturated zone is quantified and the induced delay is estimated at about 20 years in the case of the transport of a tracer.