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Seminario Prof. Kurevija: "Applying petroleum well testing techniques on thermal response test procedure and shallow geothermal systems modelling– experiences from Croatia"

13/05/2019 dalle 12:00 alle 14:30

Dove Aula TA08 - Scuola di Ingegneria - Via Terracini, 28 - Bologna

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Applying petroleum well testing techniques on thermal response test procedure and shallow geothermal systems modelling– experiences from Croatia

Prof. Tomislav Kurevija
Department of Petroleum Engineering and Energetics
Faculty of Mining, Geology and Petroleum Engineering
University of Zagreb, Croatia

May 13rd
h. 12:00-14:30
Room TA08 (Via Terracini 28, Bologna)

Abstract: The interest of using shallow geothermal energy via borehole heat exchangers and heat pump systems is on the steep rise in the last decade. When considering implementation of shallow geothermal energy as a renewable source for heating and cooling of buildings, special care should be taken in the design of the underground borehole heat exchangers.
The theory of Thermal Response Testing (TRT) is a well-known part of the sizing process of the geothermal exchange system. Multiple parameters influence the accuracy of effective ground thermal conductivity measurement; like testing time, variable power, climate interferences, groundwater effect, etc. To improve the accuracy of the TRT, a novel procedure like heat step testing and analysis of the falloff temperature decline after the power test are elaborated. These methods are based on a premise of analogy between TRT and petroleum well testing technique, since the origin of both procedures lies in the diffusivity equation with solutions for heat conduction or pressure analysis during radial flow. Applying pressure build-up test interpretation techniques to borehole heat exchanger testing, greater accuracy could be achieved since ground conductivity could be obtained from this period. Also, implementing prolonged steady-state thermal response step test, which incorporate series of power steps, can determine long-term borehole extraction rate at steady-state heat transfer conditions.
Only relying to the catalogue properties of soil, which are the crucial source of data for the modelling phase, often lead to undersized systems and functional problems. Considering this, TRT is therefore the most profitable method for modelling long-term operating geothermal systems.