关键词: CO₂驱油, CO₂注气管柱, CO₂驱油分层注气, CO₂驱油注气工艺, 苏北油田

Abstract: As the channel for CO2  to enter formation，the gas injection string is one of the important factors to ensure the successful completion of CO2  flooding. On the basis of learning from the experience of others and making sufficient investigation，four kinds of gas injection strings for CO2 flooding were designed and developed in Subei Oilfield. This paper analyzes the adaptability of all these strings，makes a comparative study on gas tightness，reliability and cost-effectiveness，and evaluates their application effects. Accord- ing to the analysis，existing CO2 injection technology can meet the demand for large-scale gas injection in Subei Oilfield，and has achieved some increase in production. However，it is found in the practical field testing that existing CO2  injection technology still has some limitations and shortcomings. Therefore，such recommendations as improving the current CO2  injection string，promoting the ap- plication of gas tightness testing technology，deepening the study on the brittle fracture mechanism of injection well tubing and casing， and paying more efforts in achieving breakthrough in the technology of separate-layer gas injection are put forward for future study.

Key words: CO₂ , flooding；CO₂ , gas  injection  string；separate-layer  gas  injection  for  CO₂ , flooding；gas  injection  technology  for CO₂ flooding；Subei Oilfield