| Molecular viscosity and contraction force | Thick oil reservoir | The condensation in the process of organic matter degradation increases the density of crude oil and forms heavy oil. The internal viscosity of molecules leads to the self-sealing accumulation of crude oil without migration | Strong effect of microbial degradation and oxidation modification Formation water salinity less than 5000 mg/l; Temperature less than 60 °C; burial depth less than 2000 m | Distributed in the area with strong tectonic change: the edge of the basin or the top of the uplift; burial depth less than 2000 m | East Venezuela basin, Orinoco heavy oil belt, western margin of Songliao Basin |
| Bitumen reservoir | In the process of organic matter degra- dation, the crude oil is transformed into bitumen by molecular condensation, resulting in the increase of density and hydrocarbon thickening, resulting in self-sealing reservoir formation | Strong effect of microbial degradation and oxidation modification Formation water salinity less than 2000 mg/L; Temperature less than 30 °C; Burial depth less than 1000 m | Distributed in the area with strong tectonic change: margin or top; common burial depth less than 1500 m | Eastern margin of Albert basin, Canada; Western margin of Junggar Basin; West slope of Liaohe depression in Bohai Bay |
| Molecular interface force (capillary force) and adsorption force | Tight hydrocarbon reservoir | The reservoir is dense due to compac- tion, and the capillary force binding effect increases, which leads to the failure of buoyancy, and the oil and gas do not migrate, resulting in self-sealing reservoir formation | The capillary force in the reservoir exceeds the buoyancy: Reservoir porosity less than or equal to 12%; Reservoir permeability less than or equal to 1×10-3 μm2; Pore throat radius less than or equal to 1 μm | Deep depression, syncline and slope with big burial depth in the basin Tight clastic rock and carbonate rock | Deep basin gas reservoirs in the Rocky Mountains, USA; Paleozoic tight sandstone gas reservoirs in Ordos Basin, China; Mahu tight conglomerate reservoir in Junggar Basin |
| Coalbed methane reservoir | Due to the strong adsorption of coal organic matter on oil and gas, the buoyancy has no effect on the migration of oil and gas, and the oil and gas are self-sealed under the adsorption of coal seam | Coalbed porosity less than or equal to 5%; Coalbed permeability less than or equal to 0.01×10-3 μm2; Coalbed pore throat radius less than or equal to 0.025 μm | Coal bearing and gas bearing basins | Walloon coalbed methane, Surat basin, Australia; Coalbed methane in Qinshui Basin, China |
| Shale oil reservoir | The adsorption of shale media and the binding of capillary force lead to the non-migration of oil and gas, while the buoyancy failure leads to self-sealing reservoir formation | High TOC mud shale Porosity less than or equal to 12% Permeability less than or equal to 0.1×10-3 μm2 Pore throat radius less than or equal to 0.1 μm | Fine grained hydro- carbon generating rock series in petroliferous basin | Barnett shale gas in Fort Worth basin, USA; Shale oil and gas in Sichuan Basin, China |
| Molecular clathration force | Natural gas hydrate reservoir | The clathration of water molecules on methane and other natural gas at high pressure and low temperature makes them aggregate into solid hydrate and form self-sealing reservoir | Hydrocarbon generating conditions at the bottom of the ocean or in the continental permafrost, strata pressure of 2-15 Mpa, temperature of -10-15 °C | Permafrost in polar regions of the earth; Marine sediments; Under the plateau ice cover, burial depth less than 1200 m | North Slope basin, Alaska, Arctic; South China Sea basin; Qinghai Tibet Plateau Basin, etc |