Associated gas usually refers to natural gas symbiotic with oil. According to the oil generation theory of organic hydrocarbon generation, when the organic matter evolves to the mature stage, liquid and gaseous hydrocarbons are generated at the same time. Some also contain non hydrocarbon gases such as carbon dioxide, nitrogen and hydrogen sulfide. Unsaturated hydrocarbon gases are rarely contained. Gaseous hydrocarbons are either dissolved in liquid hydrocarbons or exist in the upper part of the reservoir in a gas cap state. According to the theory of organic oil generation, when the organic matter evolves to the mature stage, liquid hydrocarbons and gaseous hydrocarbons are generated at the same time. Gaseous hydrocarbon, or dissolved in liquid hydrocarbon, or exists in the upper part of the reservoir in the state of gas cap. It is characterized in that the content of components above ethane is higher than that of non associated gas, and some also contain non hydrocarbon gases such as carbon dioxide, nitrogen and hydrogen sulfide, and generally contain very few unsaturated hydrocarbon gases. Associated gas can be used to produce liquefied petroleum gas, fuel and chemical raw materials. The purpose of associated gas treatment is to treat the recovered associated gas and stable gas, so as to produce liquefied gas, stable light hydrocarbon and dry gas, and improve the comprehensive utilization efficiency of oil and gas resources. In order to improve the light hydrocarbon recovery rate of associated gas, the associated gas treatment process is also changed from medium pressure shallow cold condensation fractionation process to medium pressure shallow cold oil absorption process, and the cold oil absorption process is continuously improved to form a color retention technology for treating oilfield associated gas. Stage I: medium pressure shallow cooling process - condensation fractionation method. The first light hydrocarbon recovery combined unit was built in Maling central treatment station in October 1981. It mainly processes the associated gas and stable gas outside the station to produce liquefied gas and stable light oil. The medium pressure shallow cooling process - condensation fractionation method is adopted. The unit was shut down in 1991. Medium pressure shallow cooling process - condensation fractionation is the most commonly used process for treating oilfield associated gas and recovering condensate. This process is adopted in light hydrocarbon recovery units built before 2004. The second stage: medium pressure shallow cooling process - cold oil absorption method. After 2004, the medium pressure shallow cooling process - cold oil absorption method will be developed. It was successfully applied in the light hydrocarbon recovery unit of WANGSHIBA metering transfer station for the first time, mainly treating the associated gas outside the station and volatile gas from oil tanks, and producing liquefied gas and stable light oil products. Compared with the condensation fractionation method, the cold oil absorption method has the characteristics of high C yield, good economic benefit, wide process adaptability and large operation flexibility. The process is adopted for the subsequent units with associated gas as feed gas.