Microorganisms in natural porous media can form biofilms that alter the pore structure and medium permeability. This affects fluid flow and solute transport, with bioclogging shaping the efficiency of, for example, bioremediation and hydrocarbon recovery. Here, we investigate the effect of biofilm growth on fluid flow across a wide range of flow and reaction conditions using pore-scale numerical simulations in idealized porous media. The simulation results show preferential biofilm growth and pore closure near the source of a growth-limiting substrate. This spatially heterogeneous biofilm growth at the pore scale affects the evolution of porosity and permeability. When approaching pore closure, permeability can change significantly without large changes in porosity, differentiating this setting from the empirical porosity–permeability relationships such as the Kozeny–Carman (KC) equation commonly used at the bulk scale. We find for impermeable biofilms that spatially non-uniform biofilm growths depend strongly on Péclet (Pe) and diffusive Damköhler numbers (Da) governing heterogeneous substrate distribution. We also demonstrate that Pe and Da can describe the evolution of porosity and permeability of porous media with various pore geometries, including pore throat size and tortuosity. Finally, the simulations with porous and permeable biofilms reveal significantly different evolution of porosity and permeability compared to non-porous and impermeable biofilms, highlighting the importance of micro-scale biofilm characteristics for macro-scale hydrological properties of porous media.

天然多孔介质中的微生物可以形成改变孔隙结构和介质渗透性的生物膜。这会影响流体流动和溶质运输，生物堵塞会影响例如生物修复和碳氢化合物回收的效率。在这里，我们使用理想化多孔介质中的孔隙尺度数值模拟来研究生物膜生长对各种流动和反应条件下的流体流动的影响。模拟结果显示在生长限制基质源附近优先生物膜生长和孔隙闭合。这种在孔隙尺度上的空间异质生物膜生长影响孔隙度和渗透率的演变。当接近孔隙闭合时，渗透率会发生显着变化，而孔隙率没有大的变化，将此设置与经验孔隙率 - 渗透率关系（例如通常用于批量规模的 Kozeny-Carman (KC) 方程）区分开来。我们发现对于不可渗透的生物膜，空间上不均匀的生物膜生长强烈依赖于 Péclet（Pe ) 和扩散 Damköhler 数 ( Da ) 控制异质底物分布。我们还证明Pe和Da可以描述具有各种孔隙几何形状的多孔介质的孔隙度和渗透率的演变，包括孔喉尺寸和曲折度。最后，与无孔和不渗透生物膜相比，多孔和可渗透生物膜的模拟揭示了孔隙率和渗透率的显着不同演变，突出了微观生物膜特征对多孔介质宏观水文特性的重要性。