关键词: 二氧化碳驱, 二氧化碳捕集, 方案选择, 案例分析

Abstract: CO₂ EOR and storage is an effective method to reduce greenhouse gas emission associated with tertiary oil recovery. With the CO₂ breakthrough in production wells, selection the best way to dispose the associated gas will become important. In this paper, the general rule of CO₂-associated gas produced during CO₂ injection is analyzed. The feasibility and application range of three production gas disposal options are evaluated, including direct re-injection or mixed with pure CO₂ for re-injection, combustion for power generation associated with flue gas re-injection, and CO₂ capture for rejection. The preliminary screen criteria for these gas disposal options is established. Further, four different CO₂ capture techniques are also compared in applicability and economy, including chemical absorption, low-temperature fractionation, pressure swing adsorption and membrane separation. Taking CO₂ EOR and storage projects in Weyburn and Jilin oilfields, the main process of CO₂recycling is analyzed, which can provides valuable insights for the CO₂disposal in the other CO₂ EOR and storage projects. The results show that direct re-injection or mixed with pure CO₂ for re-injection is preferred for the treatment of CO₂-associated gas in the oil field. Secondly, CO₂separation and purification of the produced gas is considered. The scale of CO₂-EOR plants are usually small or middle in domestic, which choose pressure swing adsorption and low-temperature fractionation, while the large scale plants in foreign countries once used chemical absorption and membrane separation to capture CO₂ from associated gas.

Key words: CO₂ flooding, capture and separation, scheme selection, case analysis