We investigate viscous fluid flows and concurrent fluid-driven deformations in porous media. The hydro-mechanically (H-M) coupled pore-network model (PNM) is developed, which combines the two-dimensional square-lattice PNM and block-spring model. The single-/two-phase flows into saturated deformable porous media are simulated through iterative two-way coupling method in H-M coupled PNM. A comparison between simulations and laboratory observations on flow patterns, solid deformation behaviors, and pressure responses ensures the validity of our H-M coupled PNM in both single-/two-phase flows. Parametric studies using the validated model examine the effects of mechanical coupling, stiffness of solid particles, the viscosity of invading fluids, injection flow rate, and degree of disorder during immiscible viscous fluid injection. The viscous fluid-driven deformation increases the pore throat size and hence reduces the injection pressure. In particular, the viscosity of invading fluid significantly alters the patterns of fluid propagation and solid deformation, along with a transition from the viscous fingering to the stable displacement with increasing viscosity. Moreover, the structural disorder in porous networks magnifies the irregular flow pattern, the pressure fluctuation associated with Haines jumps, and the poromechanical deformation. The particle-level force analysis delineates two distinct regimes: fluid invasion with no deformation and drag-driven deformation, which depends on the balance between the seepage drag force and the skeletal force. The presented results contribute to a better understanding of the H-M coupled fluid flows during the injection of viscous fluids into disordered-deformable porous media.

中文翻译：

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流体力学耦合孔隙网络模型研究无序变形多孔介质中的粘性流体流动

我们研究了多孔介质中的粘性流体流动和并发的流体驱动变形。开发了流体力学 (HM) 耦合孔隙网络模型 (PNM)，它结合了二维方格 PNM 和块状弹簧模型。在 HM 耦合 PNM 中通过迭代双向耦合方法模拟单/两相流入饱和可变形多孔介质。在流动模式、固体变形行为和压力响应方面的模拟和实验室观察之间的比较确保了我们的 HM 耦合 PNM 在单相/两相流中的有效性。使用经过验证的模型的参数研究检查了机械耦合、固体颗粒的刚度、侵入流体的粘度、注入流速和不混溶粘性流体注入过程中的紊乱程度的影响。粘性流体驱动的变形增加了孔喉尺寸，从而降低了注入压力。特别是，侵入流体的粘度显着改变了流体传播和固体变形的模式，随着粘度的增加，从粘性指状到稳定位移的转变。此外，多孔网络中的结构无序放大了不规则的流动模式、与海恩斯跳跃相关的压力波动和多孔机械变形。粒子级力分析描绘了两种不同的状态：无变形的流体侵入和阻力驱动的变形，这取决于渗流阻力和骨架力之间的平衡。