Zhibing Yang

• PhD
• Uppsala University

Plain Language Summary Particle transport during tow‐phase flow is frequently involved in various natural processes and engineering applications, ranging from water infiltration to oil recovery. Therefore, understanding particle transport behaviors and their impacts on two‐phase flow in porous media is essential. Here, by using confocal microscopy...

The capillary pressure curve is essential for predicting multiphase flow processes in geological systems. At low saturations, wetting films form and become important, but how wetting films control this curve remains inadequately understood. In this study, we combine microfluidic experiments with pore‐network modeling to investigate the impact of co...

Radial injection of shear-thinning fluids into rock fractures is ubiquitous in subsurface engineering practices, including drilling, hydraulic fracturing, and rock grouting. Yet, the effect of injection-induced fracture deformation on radial displacement behavior of shear-thinning fluids remains unclear. Through radial injection experiments of shea...

We investigate interfacial instability in a lifting Hele-Shaw cell by experiments and theory. We characterize the unexplored transition from stable to unstable patterns under a wide range of controlling parameters. Surprisingly, we find that the perturbation growth rate-based criterion for the onset of instability from linear stability theory is to...

The complexity and heterogeneity of pore structure present significant challenges in accurate permeability estimation. Commonly used empirical formulas neglect its microscopic and topological characteristics, thus lacking accuracy and adaptability. While machine learning (ML) and deep learning (DL) models demonstrate promising performance, but enco...

Concrete-lined pressure tunnels have been widely used for water conveyance in pumped storage hydropower. With increasing internal water pressure, the tunnels are at higher risk of leakage, and the flow regime in the surrounding rocks is likely to transition from laminar to non-Darcian. Grouting has been considered as a cost-effective technique for...

Salt precipitation is a crucial process occurring during CO2 injection into saline aquifers. It significantly alters the porous space, leading to reduced permeability and impaired injectivity. While the dynamics of precipitation have been studied within porous media, our understanding of precipitation patterns and permeability evolution within roug...

Buoyancy-driven dissolution of the solid phase is common in natural processes and subsurface applications, such as geomorphology, solution mining, and geological CO2 storage. When an external horizontal flow is imposed, the dissolution dynamics are controlled by the interplay between buoyancy-driven and forced convections. The reshaping of the soli...

Understanding the macro‐scale flow characteristics in the fractured vadose zone is of great importance for subsurface hydrological and environmental applications. Here we develop an idealized fracture network model composed of a series of linked intersections, aiming to reveal the roles of local fluid flow, storage and splitting behaviors at inters...

Two‐phase flow involving non‐Newtonian fluids in fractured media is of vital importance in many natural processes and subsurface engineering applications, such as rock grouting, groundwater remediation, and enhanced oil recovery. Yet, how the displacement dynamics is impacted by the non‐Newtonian rheology remains an open question. Here, we conduct...

Plain Language Summary Fluid‐rock dissolution is ubiquitous in natural and engineered systems, including karst formation, geological carbon sequestration, and acid stimulation. Recent developed method for CO2 sequestration relies on mineralization, which transforms CO2 into carbonate minerals through geochemical reactions involving dissolution. The...

Surfactant-enhanced aquifer remediation has been proved successful to remove dense non-aqueous phase liquids (DNAPLs) from contaminated sites. However, the underlying mechanisms of the DNAPL mobilization and solubilization at the pore scale remains to be addressed for efficient application to the field remediation system. In this work, the emerging...

Reactive-infiltration instability is an inherent nature of a solid dissolution process in a rock fracture. This instability expands the aperture (spacing) of the fracture inhomo-geneously and forms preferential dissolution channels (wormholes). The initial aperture and the flow rate play important roles in reshaping the confined geometry because th...

Fractures are ubiquitous in geological systems. As reactive fluid flow through a fracture, dissolution of the fracture walls may occur, thus altering the fracture aperture and increasing permeability. It has been recognized that gravity plays an important role in dissolving vertical fractures due to buoyancy‐driven convection. However, the role of...

Plain Language Summary Suspended particle flow and clogging in rock fractures are involved in many subsurface engineering applications and natural processes. Water‐wet particles dispersed in oil are cohesive and tend to agglomerate, clogging flow channels of crude oil to resist further recovery. Despite being common and important, the effect of liq...

Accurate determination of the wetting characteristics on mineral surfaces is critical for many natural processes and industrial applications where multiphase flow in porous media is involved. The wetting behaviors on mineral surfaces are controlled by water-mineral interactions, giving rise to various wetting characteristics, including contact line...

Colloids are ubiquitous in the natural environment, playing an important role in facilitating the transport of absorbed contaminants. However, due to the complexities arising from two-phase flow and difficulties in three-dimensional observations, the detailed mechanisms of colloid transport and retention under two-phase flow are still not well unde...

Constructing high dams in karst valleys remains a challenging issue as karst conduits provide preferential channels for flow through the foundations. The uncertainty of the karst system drastically increases the risk of leakage and hence the difficulty in seepage control at the foundations. This study examined the transient flow behaviors through a...

Miscible displacements are involved in many applications, including enhanced oil recovery and groundwater remediation. When a less viscous and miscible fluid displaces another more viscous one, an unstable front occurs, and its evolution is controlled by the interplay between diffusion and convection. Much of the research has focused on the instabi...

Microplastics are ubiquitous in the natural environment and have the potential to endanger the natural environment, ecology and even human health. A series of microfluidic experiments by using soft lithography technology were carried out to investigate the effect of flow rate, particle volume fraction, particle size and pore/throat ratio on micropl...

The dissolution dynamics of rough channels is a fundamental issue involved in widening fracture channels (cavity evolution), solution mining, and upscaling of dissolution rate. Previous studies have focused on the dissolution patterns at the sample scale, but the study of rough surface evolution at the pore scale is lacking. Here, we fabricate a so...

Single‐collector efficiency is of paramount importance in colloid filtration theory and widely used to represent the average filtration efficiency of a specific porous medium. In this work we present new formulations (unifying the stochastic and limiting trajectory cases) for efficient evaluation of the single‐collector efficiency with Lagrangian s...

The displacement of immiscible fluids in porous media is common in many natural processes and engineering applications. Under quasi-static conditions, the displacement is affected by the geometry of the porous media and wetting condition. In an ordered porous medium, i.e., the pore size is maintained constant in the transverse direction and changes...

Groundwater flow through fractured rocks has been recognized as an important issue in many geotechnical engineering practices. Several key aspects of fundamental mechanisms, numerical modeling and engineering applications of flow in fractured rocks are discussed. First, the microscopic mechanisms of fluid flow in fractured rocks, especially under t...

Unlike embankments, earth dams, and other man‐made structures, most landslide dams are formed by rapid accumulation of rock or debris rather than mechanical compaction; thus, they are loose and pose a great risk of seepage failure. Landslide materials usually have complex pore structures with randomly distributed pores of various sizes, making the...

In situ chemical oxidation (ISCO) has proven successful in the remediation of aquifers contaminated with dense nonaqueous phase liquids (DNAPLs). However, the treatment efficiency can often be hampered by the formation of solids or gas, reducing the contact between remediation agents and residual DNAPLs. To further improve the efficiency of ISCO, f...

We present an experimental and theoretical study of unsaturated flow in discrete fracture networks. The focus is on the breakthrough time of infiltrating liquid through the fracture networks as well as the spatial distribution of local flow status under a wide range of flow rates. Through visualized experiments, the fluid motion in the fracture net...

Modelling unsaturated flow in fractured rocks is essential in various subsurface engineering applications, but it remains a great challenge due to the difficulties in determining the unsaturated hydraulic properties of rocks that contain various scales of fractures. It is generally believed that the van Genuchten (VG) model applies to fractured roc...

Rock fractures are ubiquitous in geological systems and usually provide dominant pathways for fluid flow in fractured reservoirs. When the flowing fluid is reactive, fracture dissolution expands the aperture and forms various dissolution patterns that amplify the pathways. Previous works focused on the dissolution processes in Hele‐Shaw cells (para...

Plain Language Summary Rock fractures commonly serve as dominant pathways for the fluids flow in the Earth's crust. If the flowing fluid is reactive, such fluid injection into fractured reservoirs expands the fracture aperture and produces complex dissolution patterns. It then significantly affects flow pathways and is critical for many subsurface...

Hypothesis The stability of fluid–fluid interface is key to control the displacement efficiency in multiphase flow. The existence of particles can alter the interfacial dynamics and induce various morphological patterns. Moreover, the particle aggregations are expected to have a significant impact on the interface stability and patterns. Experimen...

Hypothesis: The imbibition dynamics is controlled by energy dissipation mechanisms and influenced by asymmetric wettability in a nanochannel. We hypothesize that the imbibition dynamics can be described by a combined model of the Lucas-Washburn equation and the Cox-Voinov law considering velocity-dependent contact angles. Methods Molecular dynamic...

Tunnelling activities may significantly alter the groundwater balance in a karst aquifer, but assessment of this effect remains challenging due to the complex flow geometries and strong hydrogeological heterogeneity. In this study, based on extensive site characterization of an independent hydrogeological unit (HU) in which a deep-buried tunnel is...

Fluid-driven granular transport is involved in many important geomorphological processes and industrial applications such as unconventional hydrocarbon recovery. Yet it remains challenging to fully understand the granular transport mechanisms in confined geometries. By performing simulations based on a coupled computational fluid dynamics and discr...

Packer test is a tool that has been long developed and widely used for characterizing the permeability of formation. The flow in the tested formation tends to transition from laminar to non-Darcian regime with increasing flow velocity and hydraulic gradient. But as the non-Darcian effect becomes important, how the borehole inclination and groundwat...

Understanding of microplastics transport mechanism is highly important for soil contamination and remediation. The transport behaviors of microplastics in soils are complex and influenced by various factors including soil and particle properties, hydrodynamic conditions, and biota activities. Via a microfluidic experiments we study liquid film entr...

In order to quantify CO2 residual trapping in situ, two dedicated single-well push-pull experiments have been carried out at the Heletz, Israel pilot CO2 injection site. Field data from some parts of these experiments suggests the important effect of the hydrodynamic behavior in the injection-withdrawal well. In the present work a model capturing t...

Anthropogenic disturbance of karst groundwater systems by large-scale underground engineering activities is an important topic but is difficult to address due to the compound influence of the heterogeneity and construction progression. In this study, we adopt the coupled discrete-continuum modeling approach where both the tunnels and karst conduits...

Characterizing the permeability variation in fractured rocks is important in various subsurface applications, but how the permeability evolves in the foundation rocks of high dams during operation remains poorly understood. This permeability change is commonly evidenced by a continuous decrease in the amount of discharge (especially for dams on sed...

Solid−liquid interaction plays a key role in substrate wettability and spreading dynamics of liquid droplets. Yet, how the solid−liquid interaction controls wettability and the spreading process is still not fully understood. Here, we employ molecular dynamics simulations to study water nanodroplet spreading on a flat substrate under a wide range o...

Plain Language Summary Fluid invasion into porous media saturated with another more viscous, immiscible fluid exhibits various displacement patterns. The patterns are controlled by the competition between capillary and viscous forces and significantly affect oil recovery and CO2 trapping efficiency. Although invasion patterns have been studied inte...

Two dedicated field experiments have been carried out at the Heletz, Israel pilot CO2 injection site. The objective has been to quantify the CO2 residual trapping in-situ, based on two distinctly different methods. Both experiments are based on the principle of a combination of hydraulic, thermal and/or tracer tests before and after creating the re...

Residual or capillary trapping is one of the key trapping mechanisms for CO2 geological storage. At the Heletz, Israel, pilot injection site, two dedicated field experiments have been carried out to characterize it in-situ. This paper presents the model analyses of the second of these tests, the Residual Trapping Experiment II (RTE II). In the expe...

Understanding the mechanisms of liquid movement through fracture intersections is important for prediction of fluid flow and solute transport in unsaturated fractured media. Here we present a quasi‐static model to predict the dynamic splitting behavior of liquid slugs at a T‐junction, as a simplified representation of a fracture intersection and co...

Residual or capillary trapping is one of the key trapping mechanisms for geological storage of CO2. Yet, very few studies so far have attempted to estimate the residual trapping and the related characteristic parameter, residual saturation, in situ. At Heletz, a pilot CO2 injection site in Israel a single-well push-pull experiment to estimate resid...

This study investigates the effect of heterogeneity on CO2–brine two-phase flow behavior and capillary trapping at the field scale. A model based on macroscopic invasion percolation is developed to simulate CO2 migration and trapping in strongly heterogeneous systems with bimodal permeability distributions. Stochastic simulations are performed on h...

We study fluid-induced deformation of granular media, and the fundamental role of capillarity and wettability on the emergence of fracture patterns. We develop a hydromechanical computational model, coupling a “moving capacitor” dynamic network model of two-phase flow at the pore scale with a discrete element model of grain mechanics. We simulate t...

Modeling saturated-unsaturated flow in fractured rock formations remains a challenging issue due to the difficulties in properly calibrating the unsaturated flow properties for fractured rocks. On the basis of the continuum approach, this study uses inverse modeling to determine the unsaturated hydraulic parameters of fractured rocks, loose sedimen...

Plain Language Summary Multiphase flow in fractured media is an important process involved in many natural processes and subsurface engineering applications. Geological fractures are inherently rough to various degrees. The roughness of rock fracture, inducing irregular flow passages, plays a fundamental role in the displacement of one fluid by ano...

A fundamental understanding of the fluid movement and dynamic partitioning process at fracture intersections is important to accurately predict water infiltration and contaminant transport in networks of fractures. We present an experimental study on the flow‐splitting behavior at a T‐shaped intersection. Different combinations of apertures of the...

The void space geometry of rough fractures is one of most important factors controlling two-phase flow in fractured media. This paper presents a numerical study on the effect of aperture field anisotropy on two-phase flow properties in rough fractures. By using a power spectrum based method, we generate multiple realizations of synthetic rough frac...

We study, numerically, the behavior of capillary pressure (Pc) during slow immiscible displacement in a rough fracture as a function of the degree of fracture aperture heterogeneity that results from two distinct mechanisms: normal confining stress and fracture surface correlation. We generate synthetic self-affine rough fractures at different corr...

Significance The simultaneous flow of multiple fluid phases through a porous solid occurs in many natural and industrial processes. Microscale physical mechanisms such as the relative affinity of the solid for the fluids (i.e., wettability), capillarity, and viscosity combine with pore geometry to produce a wide variety of macroscopic flow patterns...

Aquifers with quasi-linear flow pattern are frequently envisaged in fractured zones, in oil, gas or enhanced geothermal reservoirs, or in civil engineering where cut-off walls are constructed. The water flow towards a well in this linear aquifer system has been long investigated under Darcian flow condition, but remains an open issue for non-Darcia...

We develop an efficient computational model for simulating fluid invasion patterns emerging in variable aperture fractures. This two-dimensional model takes into account the effect of capillary force on the fluid-fluid interfaces and viscous pressure drop in both fluid phases. The pressure distribution is solved at each time step based on mass bala...

Characterizing the hydraulic conductivity distribution in aquifers is fundamental for groundwater models, solute transport and hyporheic exchange. Based on a total of 13,397 borehole packer test data collected at 12 high dam sites in Southwest China, the statistical distribution of hydraulic conductivity of rocks in this deep-incised valley area wa...

Plain Language Summary: The displacement of non-wetting phase by wetting phase in permeable media, known as imbibition, is central to diverse processes including enhanced oil recovery and geological carbon sequestration. As externally imposed flow rate increases during imbibition, viscous force increasingly dominates the imbibition over the capilla...

When a more viscous fluid displaces a less viscous one in porous media, viscous pressure drop stabilizes the displacement front against capillary pressure fluctuation. For this favorable viscous ratio conditions, previous studies focused on the front instability under slow flow conditions but did not address competing effects of wettability and flo...

Pore fluid pressure in a fault zone can be altered by natural processes (e.g., mineral dehydration and thermal pressurization) and industrial operations involving subsurface fluid injection and extraction for the development of energy and water resources. However, the effect of pore pressure change on the stability and slip motion of a preexisting...

High dams generally suffer from higher seepage risks in their foundations, and seepage control is an important technology for limiting the amount of leakage and improving the stability of the foundations. In this study, a procedure was proposed for optimization design of seepage control system in large-scale hydropower projects, which relies on suf...

Wetting properties of reservoir rocks and caprocks can vary significantly, and they strongly influence geological storage of carbon dioxide in deep saline aquifers, during which CO2 is supposed to displace the resident brine and to become permanently trapped. Fundamental understanding of the effect of wettability on CO2–brine displacement is thus i...

Dissolution and residual trapping of CO2 injected in saline aquifers can be influenced by injection strategies applied. In this study, we focus on the water-alternating-gas (WAG) strategy and investigate the importance of parameters needed to design an effective WAG injection sequence, including (i) CO2 and water injection rates, (ii) WAG ratio, an...

We explore the use of Gaussian process emulators (GPE) in the numerical simulation of injection into a deep heterogeneous aquifer. The model domain is a two-dimensional, log-normally distributed stochastic permeability field. We first estimate the cumulative distribution functions (CDFs) of the breakthrough time and the total mass using a computati...