Chemical-Assisted CO<sub>2</sub> Water-Alternating-Gas Injection for Enhanced Sweep Efficiency in CO<sub>2</sub>-EOR
Pengwei Fang,
Qun Zhang,
Can Zhou,
Zhengming Yang,
Hongwei Yu,
Meng Du,
Xinliang Chen,
Yuxuan Song,
Sicai Wang,
Yuan Gao,
Zhuoying Dou,
Meiwen Cao
Affiliations
Pengwei Fang
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Qun Zhang
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Can Zhou
State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China
Zhengming Yang
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Hongwei Yu
State Key Laboratory of Enhanced Oil and Gas Recovery, Beijing 100083, China
Meng Du
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Xinliang Chen
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Yuxuan Song
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Sicai Wang
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Yuan Gao
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Zhuoying Dou
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
Meiwen Cao
State Key Laboratory of Heavy Oil Processing and Department of Biological and Energy Chemical Engineering, College of Chemical Engineering, China University of Petroleum (East China), Qingdao 266580, China
CO2-enhanced oil recovery (CO2-EOR) is a crucial method for CO2 utilization and sequestration, representing an important zero-carbon or even negative-carbon emission reduction technology. However, the low viscosity of CO2 and reservoir heterogeneity often result in early gas breakthrough, significantly reducing CO2 utilization and sequestration efficiency. A water-alternating-gas (WAG) injection is a technique for mitigating gas breakthrough and viscous fingering in CO2-EOR. However, it encounters challenges related to insufficient mobility control in highly heterogeneous and fractured reservoirs, resulting in gas channeling and low sweep efficiency. Despite the extensive application and research of a WAG injection in oil and gas reservoirs, the most recent comprehensive review dates back to 2018, which focuses on the mechanisms of EOR using conventional WAG. Herein, we give an updated and comprehensive review to incorporate the latest advancements in CO2-WAG flooding techniques for enhanced sweep efficiency, which includes the theory, applications, fluid displacement mechanisms, and control strategies of a CO2-WAG injection. It addresses common challenges, operational issues, and remedial measures in WAG projects by covering studies from experiments, simulations, and pore-scale modeling. This review aims to provide guidance and serve as a reference for the application and research advancement of CO2-EOR techniques in heterogeneous and fractured reservoirs.
