Wang Jianxiang, Sun Jiafeng, Shi Jiawei, Bao Bo
School of Chemical Engineering, East China University of Science and Technology, Shanghai, 200237, China.
Lab Chip. 2025 Apr 8;25(8):1981-1992. doi: 10.1039/d5lc00019j.
During oil extraction, the recovery rates of traditional methods have been gradually declining. CO-enhanced oil recovery (CO-EOR) has been utilized since the 1960s; however, in recent years, it has garnered renewed attention due to its environmental benefits and economic advantages. However, there are few reports addressing multiphase mass transfer in micro- and nano-scale pores. This study employs microfluidic technology to simulate the pore structures of real reservoir rocks. A fracture-matrix porous medium chip with a network channel structure and a microscale porous medium chip featuring multiple pore-throat ratios were designed to investigate the effects of cross-scale interactions, network channel geometries, and the Jamin effect on fluid flow patterns and oil recovery rates during both CO miscible and CO immiscible flooding processes. The experiments demonstrated that the cross-scale effect facilitates the rapid achievement of a 100% recovery rate during CO miscible flooding, but exacerbates gas channeling during CO immiscible flooding, resulting in a decreased recovery rate. The Jamin effect becomes more pronounced with increasing pore-throat ratios, and the substantial capillary resistance generated by this effect in regions with high pore-throat ratios significantly reduces the rate of increase in recovery during CO miscible flooding, as well as the overall recovery rate during CO immiscible flooding. This study enhances the understanding of multiphase mass transfer in reservoir conditions and provides critical insights for optimizing CO-EOR strategies, ultimately contributing to more efficient oil recovery and supporting sustainable practices in the energy sector.
在石油开采过程中，传统方法的采收率一直在逐渐下降。自20世纪60年代以来，二氧化碳强化采油（CO-EOR）就已被应用；然而，近年来，由于其环境效益和经济优势，它再次受到关注。然而，针对微米和纳米尺度孔隙中的多相传质的报道很少。本研究采用微流控技术来模拟真实储层岩石的孔隙结构。设计了具有网络通道结构的裂缝-基质多孔介质芯片和具有多种孔喉比的微米尺度多孔介质芯片，以研究跨尺度相互作用、网络通道几何形状以及贾敏效应在CO混相驱和CO非混相驱过程中对流体流动模式和采收率的影响。实验表明，跨尺度效应有助于在CO混相驱过程中快速实现100%的采收率，但在CO非混相驱过程中会加剧气窜，导致采收率下降。随着孔喉比的增加，贾敏效应变得更加明显，这种效应在高孔喉比区域产生的巨大毛细管阻力显著降低了CO混相驱过程中的采收率增加速率以及CO非混相驱过程中的总采收率。本研究增进了对储层条件下多相传质的理解，并为优化CO-EOR策略提供了关键见解，最终有助于提高采油效率并支持能源领域的可持续实践。
