Natural gas is contained in underground porous strata, including oil field gas, gas field gas, coalbed gas, mud volcanic gas and biogenic gas, and a small amount of it comes from coal seams. It is a high-quality fuel and chemical raw material. Natural gas is mainly used as fuel to produce carbon black, chemicals and liquefied petroleum gas. Propane and butane produced by natural gas are important raw materials for modern industry. Natural gas is mainly composed of gaseous low molecular hydrocarbon and non hydrocarbon gas. Compressed Natural Gas (CNG) is natural gas that is pressurized (over 3,600 psi) and stored in a gaseous state in a container. It has the same composition as pipeline natural gas. Liquefied natural gas (LNG) is natural gas pressurized and stored in a liquid state in a container, which can be used to make CNG under reduced pressure. Compared with the traditional method of producing CNG, the cost of precision equipment required by this process is lower. Liquefied petroleum gas is one of petroleum products (liquefied petroleum gas, LPG), which is a colorless and volatile gas obtained by pressurizing, cooling, and liquefying refinery gas or natural gas (including oilfield associated gas). The main components of liquefied petroleum gas obtained from refinery gas are propane, propylene, butane, butene, and a small amount of pentane, pentene and trace sulfur compound impurities. The composition of liquefied gas obtained from natural gas is basically free of olefins. Natural gas condensate liquid (NGL) is a light hydrocarbon mixture with ethane, propane and butane as the main components obtained from the cryogenic separation of natural gas. Condensate oil (COND) refers to a gas reservoir that is in a supercritical state under high pressure and high temperature conditions in the formation. When it is mined on the ground, the pressure and temperature are reduced, and the liquid product condensed by retrograde condensation occurs. The uncondensed gas is called condensate gas well gas. Sometimes oil field associated gas and wet natural gas, the condensate obtained due to the decrease in temperature, is also called condensate oil, or natural gasoline.