Currently, most oilfields in China are utilizing CCUS projects to conduct large-scale secondary and tertiary oil recovery (e.g., Shengli Oilfield, Xinjiang Oilfield, etc.). As oil and gas fields enter the mid-to-late stages of development, many fields are actively upgrading their technologies to improve oil and gas recovery rates. Carbon dioxide (CO₂) flooding is a widely adopted reservoir recovery technique. When CO₂ dissolves in water within the formation, it increases the water’s viscosity by 20% to 30%. When dissolved in oil, carbon dioxide causes the crude oil to expand in volume, reduces its viscosity by 30%–80%, and lowers the oil-water interfacial tension. This facilitates increased oil production rates, improves oil displacement efficiency, and aids in the recovery of residual oil. CO₂ EOR typically increases crude oil recovery rates by 7%–15% and extends the production life of oil wells by 15–20 years. In large-scale CO₂ flooding operations, the associated gas produced during the process contains a significant proportion of CO₂. By recovering, reinjecting, and utilizing this CO₂ directly at the wellsite, a closed-loop CO₂ recycling system can be achieved. This not only significantly reduces greenhouse gas emissions into the atmosphere but also substantially lowers the costs associated with purchasing and transporting CO₂ for flooding, resulting in savings of 30%–60% on CO₂ raw material and transportation expenses.

Technical personnel from Hangzhou Kuai Kai High-Efficiency Energy-Saving New Technology Co., Ltd. and Jiangsu Huayang Liquid Carbon Co., Ltd. have jointly developed, designed, and manufactured a skid-mounted unit for the recovery and recycling of CO₂ from associated gas at oilfield wellheads. This unit is seamlessly integrated with the EOR system, enabling the maximum separation of produced oil, gas, and water, as well as on-site recycling of CO₂, without disrupting the normal operation of the EOR system. The recovered CO₂ can be reinjected into the oilfield via on-site high-pressure pumps to serve as a driving agent for enhanced oil recovery. This cycle of CO₂ utilization significantly reduces the costs of raw gas and transportation.

If an oilfield in production gradually depletes after 3–5 years of extraction, this skid-mounted wellhead associated gas CO₂ recovery and recycling unit can be easily relocated to the next new well to continue recovering and reinjecting CO₂ from the vented gas.

Therefore, the skid-mounted oilfield associated gas recovery unit can operate independently at the wellhead to recover CO₂ from associated gas for reuse. This skid-mounted oilfield associated gas recovery unit is suitable for on-site recycling at individual wellheads or nearby wellhead sites, reducing the cost of CO₂-assisted oil recovery and further improving the economic efficiency of oil production.