Fang Pengwei, Zhang Qun, Zhou Can, Yang Zhengming, Yu Hongwei, Du Meng, Chen Xinliang, Song Yuxuan, Wang Sicai, Gao Yuan, Dou Zhuoying, Cao Meiwen
College of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China.
Institute of Porous Flow and Fluid Mechanics, University of Chinese Academy of Sciences, Langfang 065007, China.
Molecules. 2024 Aug 22;29(16):3978. doi: 10.3390/molecules29163978.
CO-enhanced oil recovery (CO-EOR) is a crucial method for CO utilization and sequestration, representing an important zero-carbon or even negative-carbon emission reduction technology. However, the low viscosity of CO and reservoir heterogeneity often result in early gas breakthrough, significantly reducing CO utilization and sequestration efficiency. A water-alternating-gas (WAG) injection is a technique for mitigating gas breakthrough and viscous fingering in CO-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 CO-WAG flooding techniques for enhanced sweep efficiency, which includes the theory, applications, fluid displacement mechanisms, and control strategies of a CO-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 CO-EOR techniques in heterogeneous and fractured reservoirs.
二氧化碳强化采油（CO-EOR）是二氧化碳利用与封存的关键方法，是一项重要的零碳甚至负碳排放减排技术。然而，二氧化碳的低粘度和油藏非均质性常常导致气体过早突破，显著降低二氧化碳的利用和封存效率。水气交替注入（WAG）是一种缓解CO-EOR中气体突破和粘性指进的技术。然而，在高度非均质和裂缝性油藏中，它面临着与流动性控制不足相关的挑战，导致气窜和波及效率低下。尽管WAG注入在油气藏中得到了广泛应用和研究，但最近的全面综述可追溯到2018年，其重点是传统WAG提高采收率的机理。在此，我们给出了一份更新的全面综述，纳入了CO-WAG驱油技术在提高波及效率方面的最新进展，包括CO-WAG注入的理论、应用、流体驱替机理和控制策略。它通过涵盖实验、模拟和孔隙尺度建模的研究，解决了WAG项目中的常见挑战、操作问题和补救措施。本综述旨在为非均质和裂缝性油藏中CO-EOR技术的应用和研究进展提供指导和参考。
