Understanding the pore-scale fluid dynamics occurring during multiphase flow in porous media is important for the design of many applications including subsurface carbon dioxide storage, microfluidic devices, membrane fuel cells, and packed bed chemical reactors. To investigate the displacement dynamics of two- and three-phase flow in a hydrophobic porous medium, we use synchrotron X-ray...
The mixing behavior of oil and water is usually evaluated outside the pore space, under mixing conditions that does not correspond to porous media flow and by optical inspection. Especially the optical inspection disregards that, e.g., a little oil contamination in water may lead to a substantial coloring of the aqueous phase. A quantitative material balance is therefore difficult, if not...
The key to accelerate research and production in the energy industry resides in the efficient and generally applicable modelling of two-phase flow at the pore-scale. Here, we present the capabilities of the pore-morphology method (PMM) that we developed during the past two decades and our recent advancements.
The PMM was originally introduced in 2001 by Hilpert and Miller to model the...
Immiscible two-phase flow in porous media is a physical process encountered in a wide variety of applications, such as oil recovery, soil remediation, CO2 sequestration, as well as in several industrial systems. The models that describe two-phase flow in such porous media are traditionally based on Darcy’s law and a typically valid when both phases are continuous over the entire flow domain....
Hydrocarbon recovery from unconventional shale formations has reshaped the global energy landscapes. The presence of extensive nanopores introduces unique thermodynamic fluid phase behaviors—owing to large pressure differentials across fluid-fluid interfaces and strong fluid-wall interactions. While the nanoconfined phase behavior has been extensively studied in a single nanopore or a few...
Colloidal particles hold promise for mobilizing and removing trapped immiscible fluids from porous media, with implications for key energy and water applications. Most studies focus on accomplishing this goal using particles that can localize at the immiscible fluid interface. Therefore, researchers typically seek to optimize the surface activity of particles, as well as their ability to...
Whether it is river water slowly flowing over a sand bed, water flowing in between activated carbon electrodes in a Blue Energy setup, a gentle breeze of air across partially saturated soil or car fumes over the catalyst body in the exhaust pipe… the coupling of laminar free flow and parallel flow through porous media (Darcy) can be described by the Beavers-Joseph interface condition. The...
Recently a simple but robust model was proposed for describing foam flow in porous media. Numerical solutions to this model were found to be in good agreement with CT scanned nitrogen foam flow experiments in Betheimer sandstone cores, where the foam was stabilized by Alpha Olefin Sulfonate (AOS) surfactant, Simjoo and Zitha 2015. Here, we present analytical solutions for a further simplified...
Capillary phenomena have important consequences for fluid flow in geological systems, with relevant applications including carbon sequestration, recovery of oil and gas, and management of water resources. In capillary dominated systems where multiple length scales are present, accompanying timescales will also arise when considering the system dynamics. In these systems, the available thermal...
Geologic carbon storage at scales needed to reduce anthropogenic CO2 emissions will require sequestration in numerous rock formations. The injection of CO2 into carbonates has promise due to the high porosity, permeability and ubiquity of these rocks. Unlike sandstones, carbonates present a unique challenge in the form of high reactivity when exposed to the CO2-acidified brine. CO2-acidified...
Global climate change due to high dependence on fossil fuel has necessitated the need to deploy decarbonization technologies. Carbon capture and storage (CCS), a technology that stores CO2 permanently in the subsurface, is largely seen as necessary to reduce CO2 emissions from large-scale industrial sources. As CCS technology has become commercially viable, recent years have witnessed a large...
Multiphase flow through heterogeneous reservoir rocks is commonly found in geoscience applications. The accurate characterization of the pore space topology and fluid flow mechanisms is crucial to predict reservoir performance. This can be studied by visualizing the pore space with micro-computed tomography, allowing to construct image-based models (Bultreys et al., 2016). However, the...
There is growing evidence that the flow velocity $\vec v_p$ of an immiscible fluid mixture flowing in a porous medium depends on the local pressure gradient to a power in the range 1.5 to 2 when capillary and viscous forces compete [1]. The relative permeability equations relate the flow velocity of each immiscible fluid species, $\vec v_w$ and $\vec v_n$, to a gradient in the corresponding...
Recent work shows that fluid-fluid interactions should be included in the macroscopic description of two-phase flows, at least for highly permeable porous media. Upscaling of pore-scale equations for momentum transport leads to macroscopic equations with a mobility matrix involving four relative permeability terms. Diagonal terms are standard and extra-diagonal, also called cross-terms,...
Predicting injectivity, well productivity, trapping effectiveness and storage efficiency in subsurface reservoirs or saline aquifers requires a good understanding of how relative permeability changes with fluid saturation. While exact values of gas permeability at any given saturation are unknown, practitioners often assume that the general form of relative permeability curves are predictable...
The physical processes governing advective and diffusive gas and a counter-current, convective water movement in soil are discussed and described using flow models and in situ measurements in controlled environment experiments. We present several coupled-flow models using analytical solutions to describe simplified physical problems and/or numerical models to describe in more detail the...
Multiphase flow in porous rocks plays a crucial role in CO2 sequestration, subsurface energy storage and aquifer remediation. The main missing link in understanding the physics of this process is the transition from the length and time scales of a single pore to those of a macroscopic description. At the intermediate scale, intricate fluid distribution patterns emerge, closely tied to the...
Flow instabilities such as gravity override and viscous fingering, as well as rock heterogeneity could impact the CO2 plume migration during storage operations in underground formations. This consequently impacts the CO2 storage capacity of formations. Although over the past decade a significant amount of work has been conducted on the topic of CO2 storage in underground formations, the...
Transport of shale gas is in general a multiscale process: gas flows through the matrix, which is mainly composed of nano-size (microscale) pores, followed by a fracture network, and eventually into a wellbore. Accurate prediction of flow behavior in the shale matrix is critical for efficient development of shale gas reservoirs. Current continuum-based approaches may not be appropriate to...
We study energy dissipation in quasistatic two-fluid displacements in disordered media, analytically, numerically and experimentally. We establish the energy balance for a recent model that successfully reproduces collective capillary instabilities (Haines jumps), hysteresis and memory of pressure-saturation trajectories [1]. Strikingly, we discover that energy dissipation can emerge from...
The most common way to describe two-phase flow in porous media is to use the relative permeability equations for each phase. Also non-linear flux-force relations are now documented and in use. The energy dissipation can in both cases be well described by the entropy production in the system, or alternatively by the net entropy flow out of the system at steady state. Some of us have proposed...
Relative permeability is typically measured in core flooding experiments where the so-called steady-state method is preferred over other approaches because of the large accessible saturation range, better control and interpretability compared with other methods. Wetting and non-wetting phases are co-injected at a range of fractional flows fw and the resulting pressure drop and saturation are...
The flow of grains through confined and constricted geometries occurs in an array of industrial and natural settings. As such, various flow configurations have been extensively studied in dry and wet systems, for instance silo, Couette, avalanche and Poiseuille. Here we present experiments in which fluid-driven, non-buoyant grains, filling a horizontal channel confined from both the sides and...
Bubbles (or droplets, ganglia) emerge in porous media aftermath of flow, phase change, or chemical reactions and significantly impact the hydraulic, transport, and reactive properties of the system. However, compared to continuously connected phases, the behavior of dispersed bubbles, or ganglia, are far less understood. In particular, the thermodynamic stability of bubbles, despite their...
We start with a very simple experiment that you can reproduce in your own kitchen. Being stuck in this home office business does not mean we have to stop with the experimental activity! Make yourself some tea. No fancy loose-leaf tea, just the regular teabag from the store around the corner. Place the teabag in a cup and after you are happy with the tea’s strength, remove the bag and place it...
With the use of surfactants, the interfacial tension between oil and water can be lowered to a degree that solubilisation of oil by injection water leads to a near-miscible displacement. However, the resulting emulsification depends on the mechanisms of how the two phases contact each other and ultimately on the mixing, respectively, flow regime. While in classical test tube experiments,...
Feasibility of underground hydrogen storage (UHS) as a promising large-scale energy storage has become an attractive subject in recent years. Geological formation such as aquifers, depleted oil and gas reservoirs and salt caverns provide giant capacities for hydrogen storage. Compared with salt caverns, geological porous rock reservoirs (including aquifers and depleted hydrocarbon reservoirs)...
Understanding the physics of immiscible fluid-fluid displacement in fractures is central to many applications, including hydrocarbon recovery, groundwater contamination by nonaqueous liquids, and geologic CO$_2$ sequestration. Much of the experimental research on fluid-fluid displacement has focused on smooth fractures and, as a result, the hydrodynamic impact of roughness, especially under...
We have studied wettability effects on multiphase displacements in heterogeneous porous media by experiments on microfluidic chips. The developed analysis method on high-resolution images enabled us to link pore-scale physics and macroscopic consequences. By varying fluid properties to achieve a wide range of contact angles θ (23°≤θ≤127°), we find a non-monotonic rule of wettability effects on...
The multiphase distribution and transport properties in porous media are strongly influenced by capillary pressure and rock-fluid interactions. The influence of nano-scale wetting film caused by the disjoining pressure on the multiphase transport properties is not fully considered in the current pore scale modeling methods and it is unclear how the nano-scale wetting film influences the...
Multiphase flow is ubiquitous in natural porous media, synthetic membranes like fuel cells and microfluidics. The wetting state of these materials is one of the key controlling parameters of fluid distribution and it dictates trapping behaviour of each phase. At pore-scale, contact angle measurement by in-situ imaging of phase interfaces can explain phase trapping [1]. However, the spatial...
The flow of multiple fluids in porous materials occurs in a wide variety of important natural and engineered settings relevant for the understanding of geological CO2 storage, geothermal energy extraction, magma flow, oil and gas recovery, contaminant transport, flow in fuel cells, microfluidics in drug delivery, and the effectiveness of respirators and surgical masks. However, the...
