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Geothermal Energy

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Fig. 17 | Geothermal Energy

Fig. 17

From: Stress sensitivity of porosity and permeability under varying hydrostatic stress conditions for different carbonate rock types of the geothermal Malm reservoir in Southern Germany

Fig. 17

Results of mercury intrusion porosimetry (MIP). Cumulative mercury volume (black dashed line) and normalized frequency (blue solid line) are plotted as a function of the pore throat entry diameter. Limestone and dolomitic limestone samples generally tend to have a homogenous distribution of pore throats with sizes from micro- to meso-throats. Dolostone mostly shows distinctly larger pore throats in a rather heterogeneous distribution (skewed, polymodal), caused by large vug pores separated or connected only by very narrow pore throats. The permeability of dolostones is, therefore, often several orders of magnitude lower than that of limestone samples. The contribution of pore throats to permeability is shown as anormalized frequency for every sample (red lines)

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