Skip to main content

Science – Society – Technology

Fig. 11 | Geothermal Energy

Fig. 11

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. 11

Correlation of stress sensitivity coefficients with characteristic rock parameters. a Stress sensitivity coefficient for porosity \(c\) decreases with increasing rock strength \({\sigma }_{s}\). Samples with higher initial porosity \({\varPhi }^{i}\) are mostly more stress sensitive than those with lower \({\varPhi }^{i}\). b Correlation between the stress sensitivity coefficient for permeability \(b\) also indicates a decreasing sensitivity with increasing \({\sigma }_{s}\), but is fuzzier than for porosity. Most samples with low initial porosity \({\varPhi }^{i}\) also shows a low stress sensitivity of permeability. c Relationship of \(c\) with the drained bulk modulus \({K}_{d}\) indicates a decreasing stress sensitivity with decreasing compressibility of the porous medium. d Stress sensitivity of permeability increases with increasing stress sensitivity of porosity. High values for \(b\) compared to \(c\) indicate a decoupling of the permeability dependence from the porosity and an increasing contribution of cracks or fractures to the flow network

Back to article page