CO2 assisted steam flooding in late steam flooding in heavy oil reservoirs

XI Changfeng,QI Zongyao,ZHANG Yunjun,LIU Tong,SHEN Dehuang,MU Hetaer,DONG Hong,LI Xiuluan,JIANG Youwei,WANG Hongzhuang

Table 2 Results of steam flooding and combined steam flooding under the condition of whole oil layer perforated.

Displacement mode Stage recovery/% Stage water cut/% Steam injection pore volume multiple CO2 (foam) injection pore volume multiple Stage oil steam ratio Steam flooding 22.5 95.53 1.25 0 0.11 CO2 assisted steam flooding 7.2 94.28 0.26 0.07 0.12 CO2 foam assisted steam flooding2 10.1 95.10 0.75 0.3 0.09 Total 39.8 2.26 0.3 0.10