Table 2.

A summary of the reservoir and overburden characteristics for each CO2-bearing borehole, including the properties of the CO2, the presence of nearby seeps or faults and whether the reservoir is interpreted to be sealed or leaking CO2 to surface

Field/ReservoirBorehole name; abbreviationReservoir conditionsCO2 propertiesOverburden conditionsDistance from borehole to:Interpretation
Depth below surface (m)CO2 (%v.v)Over-pressurePorefluid factorDensity (kg m−3) (phase)Buoyancy (MPa)Evaporite (thickness)Seal thickness (m; min – max)Overpressure (ratio compared to hydrostatic)Seep name (no. in Fig. 1); distance (km)Fault distance (km) (name, sense)
Benevento SudBenevento Sud 1; BS1271098.5N0.4624±15 (dense – SC)5Y (9 m)315–2710Y (1.56)None5 (S. Matese, N); 15.7 (Telese Fault, N)Sealing
S. Arcangelo di Trimonte; SAT11520Y0.6503±11 (dense – SC)N1520–1520Y (1.62)None4.8 (S. Matese, N); 23.2 (Telese Fault, N)Sealing
Tranfaglia; Tr1277398N0.4279±6 (light – SC)Y (17 m)NoneY (1.67)Buonalbergo (1); 3.57 (S. Matese, N); 20 (Ufita Fault, N)Inconclusive
Benevento 002; Ben2330094N0.6797±9
(dense – SC)
1.8N30–600Y (1.68)None12.7 (Boiano, N); 22 (Telese Fault, N)Sealing
Monte TaburnoMonte Taburno 1; MT12093>90Y0.5569±10 (dense – SC)1.1Y (2 m)543–890N (1.08)Motta (2); 1.68 (Montesarchio, N)Inconclusive
MuscilloMuscillo; Mu169497 (low sat)N0.4139±19 (light – gas)2.2N305–305N (1.09)None>40 kmSealing
FrigentoMonte Forcuso 1; MF1112899.7N0.4200±5 (light – SC)3.5N168–1128N (1.21)Mefiteniella polla (4); 5.4
Mefite D'Ansanto (5); 1.8
4.3 (Ufita, N)Leaking
AcernoAcerno 1; Ac1426397Y0.6919±8 (dense – SC)Y (80 m)70–228Y (1.48)San Benedetto (6); 11
Contursi cluster (7); 15.5
2.6 (Sabato Valley; N); 11.5 (Volturata, N)Sealing
CapresePieve Santo Stefano 1; PSS1360092.2Y0.7830±8 (dense – SC)1.1Y (70 m)150–550N (1.08)C. Michelangelo (9); 2.5
Fungaia (10); 3.6
7.9 (Upper Tiber Valley, N)Leaking
  • If reservoir or overburden formation fluid pressures are 3 MPa above hydrostatic, then it is considered to be overpressured. For CO2 density, ‘dense’ refers to CO2 with densities greater than the critical density (ρc=464 kg m−1) and ‘light‘ refers to CO2 with densities below the critical density, and SC refers to the supercritical phase. Where column heights are not known, the buoyancy pressure, B, cannot be calculated. Further detail about the seeps (number, type, flux, temperature) are tabulated in Figure 1b. Modelled conditions in SAT1 are unreliable (see the main text for details).