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Table 1 Summary of the physical properties of the joint-free and jointed Buntsandstein sandstones measured in this study

From: Reactivation of variably sealed joints and permeability enhancement in geothermal reservoir rocks

Sample

Length (mm)

Diameter (mm)

Bedding dip (°)

Joint dip (°)

Average joint thickness (mm)

Range of joint thickness (mm)

Dry bulk density (g/cm3)

Initial connected porosity

ki (m2)

kf (m2)

Peak differential stress (MPa)

Young’s modulus (GPa)

Fracture dip (°)

Couches Intermédiaires (Box 117)

 Joint-free samples

  117A_4*

40.00

20.12

75

–

–

–

2.37

0.096

5.28 × 10–17

2.45 × 10–15

144.0

23

31

  117A_5*

38.63

19.87

67

–

–

–

2.42

0.082

1.07 × 10–16

8.77 × 10–15

145.0

28

–

  117A_8*

40.09

20.12

29

–

–

–

2.34

0.109

9.43 × 10–17

2.20 × 10–16

144.6

26

30

 Jointed samples

  117A_1*

36.37

20.14

68

7

2.5

0–4.6

2.43

0.093

5.83 × 10–17

2.78 × 10–15

134.6

17

26

  117A_2*

40.33

20.15

–

2

0.7

0–1.2

2.44

0.098

8.54 × 10–17

9.10 × 10–16

158.2

29

23

  117A_6*

40.43

20.15

–

89

0.7

0.8–2.0

2.41

0.099

6.47 × 10–17

6.94 × 10–16

165.3

27

35

  117A_7*

40.67

20.15

4

86

1.8

0.8–3.4

2.43

0.092

5.81 × 10–17

5.74 × 10–16

153.2

21

31

  117C_1

40.10

19.93

78

14

2.3

0.8–4.2

2.49

0.094

2.02 × 10–17

1.06 × 10–15

147.4

19

21

  117C_2

40.05

19.93

78

16

2.4

0.3–5.1

2.45

0.096

2.25 × 10–17

7.55 × 10–16

156.7

25

16

Couches de Karlstal (Box 179)

 Joint-free samples

  179A_21*

36.02

20.16

3

–

–

–

2.38

0.100

1.77 × 10–16

3.28 × 10–14

136.3

19

29

  179BC_24*

40.11

20.14

79

–

–

–

2.37

0.108

2.99 × 10–17

6.61 × 10–16

130.6

20

28

 Jointed samples

  179A_1

39.93

19.92

52

23

0.7

0.2–1.4

2.39

0.102

7.10 × 10–17

9.30 × 10–15

89.0

24

23

  179A_2

40.07

19.93

61

28

0.8

0.1–1.7

2.34

0.122

2.92 × 10–16

1.35 × 10–13

67.8

23

28

  179A_20*

40.45

20.18

5

84

0.4

0–6.2

2.37

0.104

1.89 × 10–16

7.52 × 10–16

128.5

18

30

  179BC_22*

40.05

20.15

90

3

0.6

0–1.0

2.40

0.100

4.58 × 10–17

1.52 × 10–16

121.0

18

32

  179BC_23*

40.93

20.16

90

5

0.9

0–1.7

2.36

0.111

1.36 × 10–16

2.00 × 10–15

120.6

22

31

  179BC_25*

39.94

20.14

90

86

0.3

0.1–0.6

2.37

0.107

2.52 × 10–17

3.02 × 10–17

130.0

21

22

  179BC_26*

40.60

20.16

90

6

0.4

0–1.0

2.33

0.120

8.58 × 10–17

3.08 × 10–15

120.9

23

29

  179BC_27*

40.40

20.16

0

90

0.9

0–1.7

2.36

0.108

1.29 × 10–16

2.75 × 10–16

104.0

20

27

Couches de Trifels (Box 388)

 Joint-free samples

  388_B1

41.42

20.04

90

–

–

–

2.28

0.142

2.14 × 10–16

2.66 × 10–15

115.4

22

33

  388_B2

41.46

20.06

90

–

–

–

2.28

0.148

1.03 × 10–16

4.85 × 10–16

115.2

21

28

  388_B3

40.93

20.06

5

–

–

–

2.27

0.152

4.68 × 10–16

8.75 × 10–16

113.5

22

39

  388_B4

41.18

20.05

1

–

–

–

2.26

0.155

5.63 × 10–16

8.32 × 10–16

112.4

22

29

  388_B5

41.28

20.05

21

–

–

–

2.29

0.145

2.11 × 10–16

5.23 × 10–16

111.8

19

30

  388_B6

40.77

20.05

15

–

–

–

2.29

0.144

2.08 × 10–16

3.62 × 10–16

103.2

16

39

 Jointed samples

  388_F1

41.49

20.03

16

6

0.9

0.5–1.9

2.32

0.134

3.55 × 10–16

6.68 × 10–16

117.9

19

35

  388_F2

41.44

20.05

–

0

0.9

0.3–1.5

2.30

0.138

5.08 × 10–16

1.13 × 10–15

120.8

22

34

  388_F3

41.10

20.04

14

22

1.4

0.7–2.2

2.31

0.136

6.66 × 10–16

1.02 × 10–15

129.3

21

31

  388_F4

40.96

20.03

–

20

1.8

1.0–2.9

2.30

0.139

7.63 × 10–16

2.59 × 10–15

129.6

20

26

  388_F5

41.21

20.06

26

90

0.8

0.4–1.3

2.27

0.151

1.28 × 10–16

1.43 × 10–15

116.6

19

34

  388_F6

41.15

20.04

30

86

0.8

0.6–1.2

2.27

0.152

2.81 × 10–16

4.33 × 10–16

119.5

22

33

  1. *denotes samples also studied by Griffiths et al. (2016); bedding/joint/fracture orientations are given in degrees and measured from the sample longitudinal axis (see Fig. 2); ki is pre-deformation permeability; kf is post-deformation permeability
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