--> Heatstore: A Numerical Well Testing Workflow For The Preliminary Design Of A High Temperature Aquifer Thermal Energy Storage (Ht-Ates) System In Geneva

AAPG European Region, 3rd Hydrocarbon Geothermal Cross Over Technology Workshop

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Heatstore: A Numerical Well Testing Workflow For The Preliminary Design Of A High Temperature Aquifer Thermal Energy Storage (Ht-Ates) System In Geneva

Abstract

The HEATSTORE project aims to advance the commercial viability of HT-UTES technologies by reducing cost and risk while increasing performance of such systems. As part of the project, an assessment of the heat storage potential of the subsurface is currently underway in the Canton of Geneva, Switzerland. This assessment will be followed by the creation of design plans for the development of a High Temperature Aquifer Thermal Energy Storage system (HT-ATES). To this end, well tests (a.k.a pressure transient tests) will likely serve as a main foundation for reservoir model building as well as a provider of dynamic data about formation units and associated wells. Our aim is to create a workflow that allows for future comparison of real well test data, ultimately improving the quality of the geological interpretation as well as the geometrical-geological simulation models. Basing ourselves in stratigraphic data provided by our project partners (i.e. University of Geneva, Services Industriels de Genève) to generate the corresponding geological model of the site, we analysed numerical well testing results using an otherwise simplified simulation model that resembles the more complex Greater Geneva Basin geology. Assuming rock material to be a heat-conductive non-mechanically-deforming porous medium subjected to heat transporting, compressible single-phase porous media flow, we constructed a numerical simulator to estimate the transient pressure, temperature, and fluid density responses to sets of input parameters defined by typical well tests (e.g. build-up, draw-down, interference). Through this well test analysis, we can obtain dynamic data such as permeability, proximity to boundaries and faults, lateral/vertical continuity (e.g. presence of reef structures), formation capacity, initial or average reservoir pressure, near well bore conditions, and inter-well communication situations. By establishing such a numerical well testing workflow, we can examine the plausibility of the characterisation of selected prospective drilling sites and associated aquifers iteratively, thus leading to a much better informed assessment of cost and risk.