Indirect Methods for Validating Shallow Geothermal Potential Using Advanced Laboratory Measurements from a Regional to Local Scale—A Case Study from Poland
Open Access
- 21 October 2020
- Vol. 13 (20), 5515
- https://doi.org/10.3390/en13205515
Abstract
This paper presents a broad overview of laboratory methods for measuring thermal properties and petrophysical parameters of carbonate rocks, and analytical methods for interpreting the obtained data. The investigation was conducted on carbonate rock samples from the Kraków region of Poland in the context of shallow geothermal potential assessment. The measurement techniques used included standard macroscopic examinations; petrophysical investigations (porosity, density); analysis of mineral composition thermal conductivity (TC) and specific heat measurements; and advanced investigations with the use of computed tomography (CT). Various mathematical models, such as layer model, geometric mean, and spherical and non-spherical inclusion models, were applied to calculate thermal conductivity based on mineralogy and porosity. The aim of this paper was to indicate the optimal set of laboratory measurements of carbonate rock samples ensuring sufficient characterization of petrophysical and thermal rock properties. This concerns both the parameters directly characterizing the geothermal potential (thermal conductivity) and other petrophysical parameters, e.g., porosity and mineral composition. Determining the quantitative relationship between these parameters can be of key importance in the case of a shortage of archival thermal conductivity data, which, unlike other petrophysical measurements, are not commonly collected. The results clearly show that the best correlations between calculated and measured TC values exist for the subgroup of samples of porosity higher than 4%. TC evaluation based on porosity and mineral composition correlation models gives satisfactory results compared with direct TC measurements. The methods and results can be used to update the existing 3D parametric models and geothermal potential maps, and for the preliminary assessment of geothermal potential in the surrounding area.This publication has 17 references indexed in Scilit:
- Comparison of thermal and elastic properties of sandstones: Experiments and theoretical insightsGeothermics, 2018
- Szacowanie wartości współczynnika przewodności cieplnej piaskowców fliszowych na podstawie składu mineralnegoNafta-Gaz, 2018
- Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logsGeophysical Journal International, 2015
- Thermal Conductivity of Rocks and MineralsPublished by Wiley ,2013
- New approaches for the relationship between compressional wave velocity and thermal conductivityJournal of Applied Geophysics, 2012
- On the determination of thermal conductivity of sedimentary rocks and the significance for basin temperature historyPetroleum Geoscience, 2009
- Using neural networks to predict thermal conductivity from geophysical well logsGeophysical Journal International, 2006
- Thermal conductivity from core and well log dataInternational Journal of Rock Mechanics and Mining Sciences, 2005
- Thermal conductivity of selected claystones and mudstones from EnglandClay Minerals, 1998
- Thermal conductivity of fluid-saturated rocksJournal of Petroleum Science and Engineering, 1989