Cai Liyuan, Wu Jingchun, Zhang Miaoxin, Wang Keliang, Li Bo, Yu Xin, Hou Yangyang, Zhao Yang
Key Laboratory for EOR Technology (Ministry of Education), Northeast Petroleum University, Daqing 163318, China.
Nanomaterials (Basel). 2024 Jul 30;14(15):1280. doi: 10.3390/nano14151280.
Carbon Capture, Utilization, and Storage (CCUS) stands as one of the effective means to reduce carbon emissions and serves as a crucial technical pillar for achieving experimental carbon neutrality. CO-enhanced oil recovery (CO-EOR) represents the foremost method for CO utilization. CO-EOR represents a favorable technical means of efficiently developing extra-low-permeability reservoirs. Nevertheless, the process known as the direct injection of CO is highly susceptible to gas scrambling, which reduces the exposure time and contact area between CO and the extra-low-permeability oil matrix, making it challenging to utilize CO molecular diffusion effectively. In this paper, a comprehensive study involving the application of a CO nanobubble system in extra-low-permeability reservoirs is presented. A modified nano-SiO particle with pro-CO properties was designed using the Pickering emulsion template method and employed as a CO nanobubble stabilizer. The suitability of the CO nanobubbles for use in extra-low-permeability reservoirs was evaluated in terms of their temperature resistance, oil resistance, dimensional stability, interfacial properties, and wetting-reversal properties. The enhanced oil recovery (EOR) effect of the CO nanobubble system was evaluated through core experiments. The results indicate that the CO nanobubble system can suppress the phenomena of channeling and gravity overlap in the formation. Additionally, the system can alter the wettability, thereby improving interfacial activity. Furthermore, the system can reduce the interfacial tension, thus expanding the wave efficiency of the repellent phase fluids. The system can also improve the ability of CO to displace the crude oil or water in the pore space. The CO nanobubble system can take advantage of its size and high mass transfer efficiency, among other advantages. Injection of the gas into the extra-low-permeability reservoir can be used to block high-gas-capacity channels. The injected gas is forced to enter the low-permeability layer or matrix, with the results of core simulation experiments indicating a recovery rate of 66.28%. Nanobubble technology, the subject of this paper, has significant practical implications for enhancing the efficiency of CO-EOR and geologic sequestration, as well as providing an environmentally friendly method as part of larger CCUS-EOR.
碳捕获、利用与封存（CCUS）是减少碳排放的有效手段之一，也是实现实验性碳中和的关键技术支柱。二氧化碳强化采油（CO-EOR）是二氧化碳利用的首要方法。CO-EOR是高效开发特低渗透油藏的有利技术手段。然而，直接注入CO2的过程极易发生气窜，这会减少CO2与特低渗透油基质之间的接触时间和接触面积，使得有效利用CO2分子扩散具有挑战性。本文介绍了一项关于CO2纳米气泡体系在特低渗透油藏中应用的综合研究。采用Pickering乳液模板法设计了具有促CO2性能的改性纳米SiO2颗粒，并将其用作CO2纳米气泡稳定剂。从耐温性、耐油性、尺寸稳定性、界面性质和润湿性反转特性等方面评估了CO2纳米气泡用于特低渗透油藏的适用性。通过岩心实验评估了CO2纳米气泡体系的提高采收率（EOR）效果。结果表明，CO2纳米气泡体系可以抑制地层中的窜流和重力叠加现象。此外，该体系可以改变润湿性，从而提高界面活性。再者，该体系可以降低界面张力，从而扩大驱替相流体的波及效率。该体系还可以提高CO2在孔隙空间中驱替原油或水的能力。CO2纳米气泡体系可以利用其尺寸和高传质效率等优势。将气体注入特低渗透油藏可用于封堵高气量通道。注入的气体被迫进入低渗透层或基质，岩心模拟实验结果表明采收率为66.28%。本文所研究的纳米气泡技术对于提高CO-EOR和地质封存效率具有重要的实际意义，也是更大规模的CCUS-EOR中一种环保方法的组成部分。
