Research Article
Numerical Simulation Study of Pore-Throat Evolution of Upper Paleozoic in Ordos Basin, China
Table 4
Porosity evolution of different diagenetic stage (average/data range).
| Diagenetic stage | Type of diagenesis | He 8 Member in Sulige area | Shan 2 Member in Yulin area | Quartz sandstone and lithic quartz sandstone | Quartz sandstone |
| Original porosity (%) | 33/24-36 | 34/28-38 | Early diagenesis | Compaction | Decrease 62% | Decrease 55% | Cementation | Decrease 1% | Decrease 1% | Porosity at the end of Triassic (%) | 12.2/8.9-12.6 | 14.9/12.3-16.7 | A stage of late diagenesis | Siliceous cement (Ι) | Decrease 5% | Decrease 10% | Dissolution | Increase15% | Increase 6% | Siliceous cement (ΙΙ) | 0% | Decrease 4% | Clay cement | Decrease 18% | Decrease 12% | Porosity in early cretaceous (%) | 9.2/6.7-10.8 | 8.2/6.7-9.1 | B stage of late diagenesis | Carbonate cement | Decrease 5% | Decrease 3% | Carbonate dissolution | Increase 1% | Increase 1% | Porosity in present (%) | 8.3/5.9-9.1 | 7.5/6.2-8.4 |
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