The Research Center of Multiphase Flow in Porous Media (Center for Short) has established itself as a leading institution in multiphase flow in porous media. Its foundation is closely tied to the journey of Professor Jun Yao. His academic path, culminating in a Ph.D., led him to focus on oil and gas flow in reservoirs, driven by a fascination with the complex flow phenomena in subsurface...
Abstract
For over 150 years, the quantification of fluid dynamics in porous media has been constrained by simplified homogeneous and single-phase flow assumptions originating from Darcy’s empirical work (1856). Despite significant advancements in digital rock technology, conventional subsurface assessment frameworks still rely on oversimplified porosity-permeability correlations that fail to...
Understanding snap-off dynamics in pore–throat channels with non-circular cross-sections is crucial for subsurface applications, as most natural porous rocks exhibit complex geometrical features. The fundamental mechanism governing snap-off in non-circular pore–throat systems is identified as a curvature-gradient-driven instability, which is further modulated by geometric constraints and fluid...
The vadose zone plays a pivotal role in modulating subsurface ecological processes, biogeochemical cycles, contaminant transport, critical element retention, and agricultural productivity. However, elucidating solute transport through its inherently complex and heterogeneous architecture remains a fundamental challenge in hydrogeology and soil science. This study presents soil-embedded...
The pervasive production and consumption of plastics in daily life have resulted in the accumulation of vast quantities of fragmented and primary microplastics (MPs) in the natural environment. These contaminants pose a severe challenge in the 21st century, infiltration soil and water resources and bioaccumulating across the food web, thereby threatening human and ecosystem health. Soil porous...
Dissolution–precipitation reactions in fractured rocks are central to subsurface energy applications such as CO₂ mineralization, geothermal operations, and long-term storage of reactive fluids. In diffusion-dominated, dead-end fractures, limited advective supply of reactants can promote localized mineral precipitation and clogging, degrading injectivity and long-term storage performance. To...
Natural gas hydrates, abundant in ocean floor sediments and permafrost regions, represent a promising unconventional energy resource. Current production methods interfere with the thermodynamic equilibrium to stimulate hydrate dissociation, releasing methane and water while altering formation porosity and permeability. Accurately estimating relative permeability during dissociation is critical...
CO2 dissolution is a crucial long-term storage mechanism in subsurface CO2 storage, involving complex multiphase flow coupled with various physicochemical processes. In this study, we propose a novel lattice Boltzmann framework that integrates multiphase flow, solute transport, phase transitions, and chemical reactions to simulate the CO2 dissolution process in saline aquifers under convective...
Underground hydrogen storage (UHS) is a key technology for large-scale renewable energy storage, and the efficiency and benefits of UHS depend primarily on storability and injectability of hydrogen. The pore-scale mechanisms governing hydrogen-brine displacement, trapping, and remobilization fundamentally control these macroscopic storage properties. In this study, we develop a multiphase...
Two-phase fluid displacement in a pore space with variable surface energies and wettability to fluids is characterised by the dynamics of the contact line (CL) between fluid-fluid and the wall surface, subject to the balance of all participating forces acting on the fluids. Understating the dynamics is critical for assessing performance of EOR and CCS projects. In a two-phase capillary system...
Biofilms profoundly alter flow and transport in porous media, yet their growth and clogging dynamics remain difficult to predict because biofilms behave neither as rigid solids nor as Newtonian fluids. Here we combine microfluidic experiments in well-defined porous architectures with rheology-informed modeling to reveal how fluid shear stress controls biofilm morphology and deformation. Using...
Understanding fluid behavior in subsurface energy systems requires insight across multiple length scales, from molecular- and phase-level thermodynamics to pore-scale transport in complex geological media. While conventional laboratory techniques such as core flooding and bulk PVT analysis remain essential, they often lack the ability to directly resolve the physical mechanisms governing...
Miscible CO2 injection in tight formations is crucial for carbon sequestration and enhanced hydrocarbon recovery, where the minimum miscibility pressure (MMP) between CO2 and hydrocarbons at the nanoscale is a key fluid property to be determined. Here, we developed a novel nanofluidic slim-tube method that enables direct visualization of CO2-hydrocarbon miscible behavior and in situ...
The past decade has witnessed a paradigm shift in our understanding of Ostwald ripening within confined geometries. In late 2016, experimental groups at Stanford and UT-Austin independently observed a counterintuitive phenomenon: gas bubbles in porous media exhibited self-regulated coarsening, converging toward a uniform curvature distribution rather than unlimited growth. In the end of 2017,...
Reaction flow in porous media fundamentally couples fluid flow and chemical reactions, dynamically altering material properties, including permeability, porosity, and mechanical strength. This study utilizes a pore-scale model to analyze how dissolution patterns, classified by the Damköhler (Da) and Péclet (Pe) numbers, affect the elastic properties of carbonate rocks. Our simulations...
The process of constructing digital cores typically presents a trade-off between the physical dimensions of the core sample and the scanning resolution. In unconventional reservoirs such as shale, pore distribution spans scales from the nanometre to the millimetre, even centimetre levels. Single scanning often fails to meet requirements. Coupling structures scanned at multiple resolutions to...
An oil droplet suspended in a surfactant solution can undergo micellar solubilization at its interface when the surfactant concentration exceeds the critical micelle concentration, thereby enabling autonomous propulsion; such droplets are referred to as chemically active droplets. The self-propulsion of an active droplet is governed by the nonlinear coupling among chemical transport in the...
Core CT imaging is a fundamental tool for fracture identification, quantitative pore-structure characterization, and the estimation of reservoir and engineering parameters. However, its application to multiscale reservoir storage space characterization remains challenging due to limitations in image resolution, contrast, and scale heterogeneity. Here, we develop a Smart Core workflow for the...
The success of subsurface hydrogen storage depends not only on where injected gas migrates, but how fast it equilibrates with formation water — a process critical for pressure stabilization, containment assessment, and long-term safety. Here, we demonstrate that local injection rate, a controllable operational parameter, exerts non-local control over system-scale chemical equilibration: higher...
We have developed a multi-continuum model for CO2 flow, transport and storing in fractured vuggy karst formations. The objective of this study is to develop a modeling tool for evaluating the potential and effectiveness of karst aquifers as alternative CO2 storing formations. A multi-continuum model, representing rock matrix, fracture, and vuggy continua, is applied to capture the complexity...
- Objective/Scope
The accurate and efficient localization of CO2 leakage in subsurface formations is critical to ensuring the security and success of geological carbon sequestration (GCS) projects. However, this task poses significant challenges due to the inherent uncertainties associated with subsurface environments. In this study, we propose a novel Bayesian framework, enhanced with deep...
Carbon dioxide sequestration in post-burn Underground Coal Gasification (UCG) cavities is a complex process involving disparate flow regimes. To accurately capture the physics of CO2 injection into a water-saturated cavity, this study constructs a sophisticated multi-region geometric model considering both the open-void space and the surrounding porous boundaries.
We implement a comprehensive...
Accurate simulation of CO2 sequestration in deep saline aquifers requires a consistent treatment of history-dependent processes that control immobilization and trapping, including capillary-pressure and relative-permeability hysteresis as well as dissolution-driven feedback on phase saturations. Operator-Based Linearization (OBL) is an efficient and robust framework for large-scale...
Enhanced Geothermal System (EGS) with multilateral wells is a promising method for developing deep geothermal energy. However, how to stimulate desired pathways for optimizing heat extraction from multilateral-well EGSs poses a significant challenge, particularly in figuring out what stimulated fracture pattern exhibits and its impact on heat production in EGSs with diverse distribution of...
In natural rocks, there exists a trade-off between field of view and resolution, resulting in the presence of sub-resolution pores within the current observational scope. Taking shale as an example, different types of sub-resolution matrix pores exhibit distinct pore structures and flow capacities. Single-scale imaging techniques cannot comprehensively characterize the pore structure of the...
We present a general framework for multicontinuum homogenization for the
heterogeneous porous media flows. Multicontinuum homogenization is conceptually derived from multiscale finite element methods, particularly, the Generalized Multiscale Finite Element
Method (GMsFEM) and the Constraint Energy Minimizing GMsFEM. The latter approaches are shown to have a first-order convergence...
In this work, we report a continuum model that incorporates the percolation effect for slow evaporation in capillary porous media. In order to evaluate such continuum model, we perform a pore-scale simulation based on a large pore network composed of about 2.5 million pores. Key transport parameters, such as capillary pressure and relative permeability, are derived directly from the large...
Understanding and controlling multiphase fluid transport across complex interfaces remain central challenges in both natural and engineered systems. This study investigates gradient-regulated interfacial behavior and multiphase transport governed by two distinct driving modes: internal gradients, such as geometric and wettability variations that require no external energy input, and external...
Mineral dissolution during CO2 geological storage significantly alters the structural integrity and long-term storage capacity of reservoirs. This study investigates the reactive transport and mineral dissolution processes induced by CO2-saturated brine injection across three porous rocks with distinct pore-space geometries. Utilizing micro-CT images, we employ a micro-continuum method coupled...
Reservoir history matching aims to infer key subsurface parameter fields, such as permeability, from dynamic production data, and it provides an essential basis for reservoir simulation and development decision-making. Early history matching mainly relied on expert knowledge and repeated trial-and-error adjustments, which were labor-intensive and highly subjective. It later evolved into...
In-depth understanding of gas and oil phase behavior in shale nanopores is of significant scientific importance for accurately predicting shale reservoir production. The confinement effects induced by the abundant meso- and nanopores developed in shale formations significantly alter the phase behavior of hydrocarbons. Although numerous studies have focused on the phase transition...
In the fields of engineering and science, the coupled flow and geomechanics problem is of significant importance in various applications, especially in hydraulic fracturing, CO$_2$ injection and storage, sand production, and wellbore stability prediction. In fractured media, the coupling of flow and geomechanics is particularly critical, as fractures are not only regions of mechanical...
Fractured natural and synthetic porous media (like crystalline and sedimentary rocks, concrete, etc. ) induces a number of fluid‐flow mechanisms causing attenuation of waves at different frequency regimes.
In order to characterize fractured porous media, we conducted harmonic fatigue experiments at triaxial stress conditions on fluid-saturated sandstone and concrete samples and...
Fractured vuggy carbonate reservoirs are critically important, contributing significantly to hydrocarbon reserves and production. The presence of fractures and vugs distinctly influences fluid flow and transport within carbonate rocks, differentiating fractured vuggy carbonate reservoirs from most other geological formations. Apart from matrix carbonate rocks, isolated fractured vuggy...
Acid fracturing is a pivotal stimulation technique for enhancing recovery in carbonate reservoirs. However, accurately predicting fracture propagation is challenging due to the intricate interplay of acid-rock reactions, fluid dynamics, and rock mechanics, further complicated by reservoir heterogeneity and natural fractures. This study presents a comprehensive Hydro-Mechano-Chemical (HMC)...
Conformance control in waterflooding operations is a crucial strategy for enhancing sweep efficiency and improving oil recovery in heterogeneous reservoirs. These reservoirs are often characterized by high salinity and elevated pressures, presenting significant challenges for traditional profile control agents. Preformed particle gels (PPGs) have emerged as effective agents to selectively...
Wettability, quantified by the contact angle, is a key property of porous media influencing the capillary pressures, the fluid–solid interfacial area, and eventually reaction and mass transfer processes. Recent advances in imaging enable the direct extraction of contact angles from 3D image data. However, available extraction methods often produce non-physical extreme angles that obscure the...
Understanding multiphase flow at the pore scale is critical for addressing energy and environmental challenges such as enhanced oil recovery (EOR) and CO₂ geological sequestration. However, capturing the dynamic evolution of multiphase flows of real rock samples at the micro-scale remains a significant challenge due to the limitations of conventional imaging techniques, particularly in terms...
Underground hydrogen storage (UHS) in geological formations is a promising method for storing hydrogen, with cycles of hydrogen injection and withdrawal typically anticipated for long-term development. However, the impact of local capillary trapping on the amount of hydrogen that can be stored and recovered over the entire period remains unclear. Furthermore, the selection of a suitable...
To clarify the flow capacity evolution mechanisms for hydraulic fracture networks for deep shale gas reservoirs, is a theoretical prerequisite for accurate production prediction and production strategies optimization. Given that the shale gas flow is characterized by multi-scale and multi-field coupling, the influence of water-rock interactions and in-situ stress change on seepage capacity...
CO₂ injection is a key technological approach for enhancing shale oil recovery rates and achieving geological CO₂ sequestration. Investigating the effects of CO₂ on the pore structure and hydrophilicity of shale oil reservoirs under in-situ temperature and pressure conditions holds significant implications for the development of the Gulong Shale. This study investigates Gulong shale subjected...
Accurate prediction of stress evolution induced by production pressure depletion after hydraulic fracturing is essential for efficient development of stacked continental shale reservoirs. This study establishes a three-dimensional stress sensitivity and flow coupling framework to characterize intra-layer and interlayer stress evolution during stereoscopic shale oil development. A 3D discrete...
Horizontal well fracturing is widely regarded as the most effective technology for enhancing the recovery rate of shale-gas reservoirs. Due to the complex flow mechanisms and significant reservoir heterogeneity, the collaborative optimization of well-fracture pattern parameters is highly challenging. In multi-well development optimization, the number of wells itself cannot be predetermined,...
