Similarities and differences between oil pools and gas pools in their formation mechanisms and distribution characteristics

This paper has mainly discussed the similarities and differences between oil pools and gas pools in the respects of hydrocarbon sources, reservoir properties, migration and accumulation mechanisms, and preserving conditions. As mineral deposits, both oil and natural gas pools have similar conditions for the formation and preservation; they need hydrocarbons concentrations by migration and relative stable preserving conditions, etc. Compared with oil pools, gas pools have many particular properties, such as multiple gas sources, combination of variety of gases, lower standard of reservoirs and higher standard of cap rocks, etc. Because natural gas can easily migrate and has many states of migration, there are many formation mechanisms for the gas pools; convection migration of gas and the separation of dissolved gas may be an important migration and formation mechanism for the gas pools.