In the process of working, natural gas can be directly divided into free state, dissolved state, adsorbed state and solid hydrate according to the phase state existing in the ground. Only the free natural gas can be developed and utilized by agglomerating to form a natural gas reservoir. According to the form of deposit generation, natural gas can be divided into two types: associated gas and non-associated gas.
Natural gas is accompanied by crude oil symbiosis, and oil gas produced at the same time as crude oil. The associated gas is usually the volatile part of crude oil, which exists in the form of gas on the oil-bearing layer. In all the layers with crude oil, the ratio of oil and gas is different. Even oil and gas sources in the same field are not necessarily the same. They are brought together in the same rock reservoir by different pathways and through different processes.
Natural gas includes both pure gas field natural gas and condensate gas field natural gas, which are in a gaseous state in the formation. After the natural gas flows out of the wellhead from the formation, the gas is separated into gas-liquid two phases as the pressure drops and the temperature rises. The gas phase is the natural gas in the condensate gas field, and the liquid phase is the condensate, called condensate. In the case of non-associated gas, it is not related to liquid accumulation and may be produced from plant matter. Among the world's natural gas production, it is mainly gas field gas and oil field gas. The exploitation of coalbed methane has received increasing attention.www.wxytgas.com