Table 3 Favorable exploration regions, resource potential, and exploration targets for ultradeep (>10 km) major gas field groups in China
From: Ultradeep drilling beyond 10 km revealing new insights into Earth systems and resources
Basin | Reservoir-caprock combination | Exploration field | Prospective area (km2) | Favorable conditions and resource potential |
|---|---|---|---|---|
Tarim Basin | Lower Cambrian dolomite/Middle Cambrian evaporites | Cambrian subsalt in the Tarim Basin. | 18,000 | Excellent source–reservoir–seal systems from Lower Cambrian rocks with trillion-m³ gas potential. |
Tarim Basin | Ordovician limestone/Sangtamu Formation mudstone | Ordovician in the Tarim Basin. | 15,000 | Multiphase tectonics created fracture–cavity reservoirs and km-scale oil columns, enabling billion-ton oilfields. |
Tarim Basin | Carboniferous-Permian carbonate/Permian mudstone | Carboniferous-Permian in the southwestern Tarim Basin. | 11,000 | Long-term marginal setting since Cambrian built multiple carbonate platforms with low exploration maturity—a strategic replacement area. |
Tarim Basin | Triassic Huangshanjie/Karamay sandstones/Taligike coal measures | Triassic in the Kuqa Depression. | 6000 | Deep structural traps with Triassic sources remain underexplored but promising. |
Sichuan Basin | Sinian Dengying Formation/Lower Cambrian Gaotazi Formation | Sinian-Cambrian in the eastern Sichuan Basin. | 8000 | Paleo-uplifts and slopes provide favorable large trapping potential. |
Sichuan Basin | Permian Changxing Formation/Triassic Feixianguan Formation | Permian-Triassic reef-shoal complexes in the northeastern Sichuan Basin. | 5000 | Multiple high-quality source rocks with extensive reef-shoal distributions. |
Sichuan Basin | Sinian Dengying Formation/Cambrian Longwangmiao Formation | Eastern and western platform margins of the northern segment of the aulacogen. | 3000 | Optimal source-reservoir configuration with estimated 2 trillion m³ gas potential. |
Ordos Basin | Meso-Neoproterozoic/ Cambrian/Ordovician Majiagou Formation | Pre-Salt Ordovician. | 8000 | Multiple effective plays with low exploration maturity but promising potential. |
Junggar Basin | Cretaceous Qingshuihe Formation/Paleogene Anjihaihe Formation | Southern margin of the Junggar Basin. | 7000 | Jurassic coal measures and Permian Lucaogou sources could support a trillion-m³ gas province. |
Junggar Basin | Carboniferous-Permian/Triassic Baijiantan Formation | Deep strata in the Shawan Sag. | 12,000 | Permian Fengcheng sources with multiple seal combinations offer large-scale gas potential. |
Qaidam Basin | Jurassic-Paleogene/Paleogene | Jurassic in the northern margin of Qaidam Basin. | 1000 | Jurassic coal-derived hydrocarbons with 5–8% porosity below 8 km favor ultradeep gas field development. |
