Table 1
Cenozoic strata lithology and fluid production status in Tianjin.
| System | Formations and thickness | Section | Lithology | Production status |
|---|---|---|---|---|
| Quaternary | Q (–) | Mudstone, sandy mudstone, and sandstone | Industrial oil flows | |
| Neogene | N2 m (600–1000 m) | Upper | Fine siltstone, sandstone, and mudstone | Hot water extraction layer with water flow rates of 40–100 m3/h and T = 40–80 °C |
| Lower | ||||
| N1 g (300–900 m) | N1 g 1 | Medium-coarse sandstone interlayered with mudstone | Main geothermal reservoir with water extraction rates of 80–130 m3/h and T = 48–82 °C | |
| N1 g 2 | ||||
| N1 g 3 | ||||
| Paleogene | E3 d (100–800 m) | E3 d 1 | Mudstone interlayered with sandstone and gravel-bearing sandstone | Wellhead flowing rates of 40–80 m3/h and wellhead flowing T = 78–93 °C |
| E3 d 2 | ||||
| E3 d 3 | ||||
| Es (800–2100 m) |
|
Upper part is mudstone; lower part is mudstone interlayered with limestone, dolomite, shale, and siltstone | Industrial oil flows, e.g., Shuguang oilfield | |
|
Upper part is sandstone interlayered with mudstone; lower part is carbonaceous shales and sandstones | Industrial oil flows, e.g., in Shengli oilfield | ||
|
Sandstone interlayered with mudstone and oil shale | Industrial oil flows, e.g., in Shengli oilfield and Shuguang oilfield | ||
|
Sandstone interlayered with mudstone and oil shale | Industrial oil flows | ||
| Ek (250–2500 m) | Sandstone, dolomite, mudstone, carboniferous shale, and conglomerate | Industrial oil flows |