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

Geothermal Energy

Science – Society – Technology

Table 2 Rock specific characteristics and petrophysical description of investigated rock samples

ID	Lithology	Facies	Depth	\({\varPhi }^{i}\)	\({\varPhi }^{\mathrm{max}}\)	\({\varPhi }^{\mathrm{MI}P}\)	\({k}_{i}\)		\({\rho }_{\mathrm{b}}\)	\({\rho }_{\mathrm{m}}\)	\({d}_{\mathrm{eff}}\)
ID	Lithology	Facies	mTVD	%			mD	m²	g cm⁻¹		µm
L1	Limestone	Grainstone	258	13.0	14.3	5.5	4.574	4.5E⁻¹⁵	2.32	2.71	8.1
L2	Limestone	Grainstone	259	14.5	15.2	15.2	3.754	3.7E⁻¹⁵	2.29	2.71	10.0
L3	Limestone	Grainstone	1132	18.1	20.2	18.2	4.423	4.4E⁻¹⁵	2.17	2.72	5.2
L4	Limestone	Rudstone	1148	12.7	13.9	17.3	0.161	1.6E⁻¹⁶	2.34	2.71	0.6
L5	Limestone	Grainstone	0	15.8	17.2	–	0.105	1.0E⁻¹⁶	2.24	2.71	–
dL1	Dolomitic limestone	Grainstone	996	13.0	14.9	13.1	0.746	7.4E⁻¹⁶	2.36	2.77	2.2
dL2	Dolomitic limestone	Grainstone	1139	15.0	15.8	13.3	0.540	5.3E⁻¹⁶	2.34	2.77	1.5
D1	Dolostone	Fine-X	1303	14.9	16.7	16.9	1.287	1.3E⁻¹⁵	2.36	2.83	5.0
D2	Dolostone	Fine-X	1306	9.8	14.1	8.5	0.962	9.5E⁻¹⁶	2.42	2.82	2.5
D3	Dolostone	Medium-X	409	8.9	9.4	6.3	4.454	4.4E⁻¹⁵	2.55	2.81	7.2
D4	Dolostone	Medium-X	424	8.2	9.3	6.4	0.815	8.0E⁻¹⁶	2.54	2.80	4.1
D5	Dolostone	Medium-X	1370	2.3	7.2	2.5	0.003	3.0E⁻¹⁸	2.62	2.82	0.8
D6	Dolostone	Coarsely-X	263	9.2	10.4	–	0.433	4.3E⁻¹⁶	2.39	2.67	–
D7	Dolostone	Coarsely-X	459	4.0	5.7	3.7	0.006	5.9E⁻¹⁸	2.64	2.80	0.15
D8	Dolostone	Coarsely-X	462	3.7	5.4	3.4	0.007	6.9E⁻¹⁸	2.65	2.81	0.25

\({\varPhi }^{i}\) effective porosity for water, \({\varPhi }^{\mathrm{max}}\) maximum effective porosity for helium, \({\varPhi }^{\mathrm{MIP}}\) effective porosity by mercury injection, \({k}_{i}\) initial permeability, \({\rho }_{\mathrm{b}}\) bulk density, \({\rho }_{\mathrm{m}}\) particle density, \({d}_{\mathrm{eff}}\) effective pore throat diameter, X crystalline