Research Article
Evaluating the Sealing Effectiveness of a Caprock-Fault System for CO2-EOR Storage: A Case Study of the Shengli Oilfield
Table 1
Indicators and ranking system for a caprock-fault system for CO
2-EOR storage [
27,
30,
37–
40].
| | I | II | III
Specific indicators | Very Good | Good | Normal | Poor | Very Poor | | 5 | 4 | 3 | 2 | 1 |
| | Fault caprock sealing system | Caprock | Displacement work (MPa·m) | | >6300 | 2100~6300 | 350~2100 | <350 | | Porosity (%) | | <5 | 5~10 | 10~15 | >15 | | Permeability (mD) | | <0.1 | 0.1~1.87 | 1.87~10 | >10 | | Shale content (%) | | >75 | 75~50 | 50~25 | <25 | | Well density (/10 km) | 0 | 1~2 | 3~5 | 5~10 | >10 | | Fault | Fault activity time | | Tranche | Syngenetic | Multiperiod | | | Configuration relationship between fault extension and caprock | | Embedded type | Lower broken type | Broken-through type | | | Configuration relationship between fault throw and direct caprock thickness | | Intact top seal type | Seal connected type | Seal apart type | | | Fault dip angle (°) | | ≤45 | 45~75 | >75 | | | Fault lateral displacement work (MPa·m) | | >30 | 2.5~30 | | <2.5 | | Fault vertical displacement work (MPa·m) | | >6300 | 2100~6300 | 350~2100 | <350 | | Fault lateral permeability (mD) | | <0.001 | 0.001~0.0187 | 0.0187~0.1 | >0.1 | | Fault vertical permeability (mD) | | <0.001 | 0.001~0.0187 | 0.0187~0.1 | >0.1 | | Fault tightness coefficient | >1 | | | | <1 | | Shale smear factor | <4 | | 4~7 | | >7 | | Clay smear potential | >35 | | 15~35 | | <15 | | Shale gouge ratio | >0.5 | | 0.3~0.5 | | <0.3 |
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