Song Yuxuan, Zhang Qun, Zou Xinyuan, Fan Jian, Wang Sicai, Zhu Yan
Institute of Porous Flow and Fluid Mechanics, Chinese Academy of Sciences Langfang Hebei 065007 China.
Research Institute of Petroleum Exploration and Development Beijing 100083 China.
RSC Adv. 2025 Jan 9;15(2):714-731. doi: 10.1039/d4ra07300b.
Supercritical CO, as an environmentally friendly and pollution-free fluid, has been applied in various EOR techniques such as CO flooding. However, the low viscosity of the gas leads to issues such as early breakthrough, viscous fingering, and gravity override in practical applications. Although effective mobility-control methods, such as CO WAG (water alternating gas)-, CO foam-, and gel-based methods, have been developed to mitigate these phenomena, they do not fundamentally solve the problem of the high gas-oil mobility ratio, which leads to reduced gas sweep efficiency. Adding CO direct thickeners to displacing fluid can increase its viscosity, achieve deeper mobility control, and thus improve the CO flooding oil-recovery effect. Unlike other methods, direct thickeners can alter the physical and chemical properties of CO, making it a fundamentally effective means of achieving mobility control. This approach can be applied in various reservoir environments and formations, or it can assist other methods for more in-depth mobility control. This article reviews the development and application of CO direct thickeners and introduces the thickening mechanisms and effects of different types of thickeners as well as their existing problems and future development directions.
超临界二氧化碳作为一种环境友好且无污染的流体，已被应用于各种提高采收率（EOR）技术，如二氧化碳驱油。然而，气体的低粘度在实际应用中会导致诸如早期突破、粘性指进和重力超覆等问题。尽管已经开发出有效的流度控制方法，如二氧化碳水交替气驱（WAG）、二氧化碳泡沫驱和基于凝胶的方法来减轻这些现象，但它们并没有从根本上解决高气油流度比的问题，这导致气体波及效率降低。在驱替液中添加二氧化碳直接增稠剂可以增加其粘度，实现更深层次的流度控制，从而提高二氧化碳驱油的采收效果。与其他方法不同，直接增稠剂可以改变二氧化碳的物理和化学性质，使其成为实现流度控制的一种根本有效的手段。这种方法可以应用于各种油藏环境和地层，或者可以辅助其他方法进行更深入的流度控制。本文综述了二氧化碳直接增稠剂的发展与应用，介绍了不同类型增稠剂的增稠机理、效果以及它们存在的问题和未来的发展方向。
