Table 3 Criteria, scores and weights used to rank the CO₂ storage potential of regions within the SMB and adjacent Jura

For evaluation of entire sediment stack at depth ≥800 m

 1a

Depth to sealed^a aquifers

>2,500 m [1]

800–2,500 m [15]

0.20

For evaluation of individual aquifers within 800–2,500 m depth interval

 1b

Thickness of sealed^a aquifer

≤20 m [1]

Maximum thickness of formation [15]

0.20

2

Geothermal gradient

>35°C/km [1]

30–35°C/km [8]

<30°C/km [15]

0.15

3

Hydrogeology

High complexity, poor knowledge [1]

Regional discharge zones [5]

Infiltration and transit zones [15]

0.15

4

Exploration maturity

Unexplored [1]

Moderate [11]

High [15]

0.15

5

Seismicity

Elevated [1]

Moderate [5]

Low [15]

0.10

6

Fault systems

High density/active/favours leakage [1]

Buried/favours traps [8]

Limited faulting [15]

0.10

7

Structural traps

Open-dipping structures [1]

Tilted faults, compartments [9]

Duplex structures [13]

Anticlinal structures [15]

0.10

8

Stress regime

Strike-slip to thrust faulting [1]

Strike-slip to normal faulting [15]

0.05