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56
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Introduction
Earth and Environmental Engineering Ph.D. with extensive laboratory, field, and modelling experience. Expertise in dynamic reservoir condition pore-scale fluid measurement, image analysis of large data sets, machine learning-based data set interpretation and forecasting, and experimental system development. Co-Founder of the GeoChemFoam project.
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Position
- PhD Student
October 2012 - October 2015
Publications
Publications (56)
The permeability of a pore structure is typically described by stochastic representations of its geometrical attributes (e.g. pore-size distribution, porosity, coordination number). Database-driven numerical solvers for large model domains can only accurately predict large-scale flow behavior when they incorporate upscaled descriptions of that stru...
We present the novel numerical model GeoChemFoam, a multiphase reactive transport solver for simulations on complex pore geometries, including microfluidic devices and micro-CT images. The geochemical model includes bulk and surface equilibrium reactions. Multiphase flow is solved using the Volume-Of-Fluid method and the transport of species is sol...
GeoChemFoam is an open-source OpenFOAM-based numerical modelling toolbox that includes a range of custom packages to solve complex flow processes including multiphase transport with interface transfer, single-phase flow in multiscale porous media, and reactive transport with mineral dissolution. In this paper, we present GeoChemFoam's novel numeric...
The current conceptual model of mineral dissolution in porous media is comprised of three dissolution patterns (wormhole, compact, and uniform) - or regimes - that develop depending on the relative dominance of flow, diffusion, and reaction rate. Here, we examine the evolution of pore structure during acid injection using numerical simulations on t...
Hypothesis
Underground hydrogen (H2) storage is a potentially viable solution for large-scale cyclic H2 storage; however, the behavior of H2 at subsurface pressure and temperature conditions is poorly known. This work investigates if the pore-scale displacement processes in H2-brine systems in a porous sandstone can be sufficiently well defined to...
Uncertainties in the subsurface challenge reliable leakage risk assessments and long-term integrity of CO2 storage. Fault zones, characterised by multi-scale heterogeneities, are critical pathways for leakage and suffer from significant data uncertainties due to unresolved features. Understanding the multi-scale uncertainties in estimating fracture...
Permeability and heat transport through building materials ultimately dictates their insulatory performance over a buildings service lifetime. Experiments combining XCT with numerical modelling are an accepted method of studying pore scale processes and have been used extensively in the oil and gas industry to study highly complex reservoir rocks....
Subsurface porous rocks hold significant hydrogen (H2) storage potential to support an H2-based energy future. Understanding H2 flow and trapping in subsurface rocks is crucial to reliably evaluate their storage efficiency. In this work, we perform cyclic H2 flow visualization experiments on a layered rock sample with varying pore and throat sizes....
Microporosity is commonly assumed to be non-connected porosity and not commonly studied in geoengineering industry. However, the presence of micropores plays a key role in connecting macropores and it can contribute significantly to the overall flow performance. In this study, targeted CO2 storage carbonate fields in Southeast Asia have significant...
To meet global commitments to reach net-zero carbon (C) emissions by 2050, the energy mix must be adjusted to reduce emissions from fossil fuels and transition to low or zero C energy sources. Hydrogen (H2) can support this transition by facilitating increased renewable (zero C) energy use by acting as an energy store to balance supply and demand....
This article discusses the impact of small-scale heterogeneity on pore-scale trapping and displacement of hydrogen in rocks for underground hydrogen storage.
The traditional model of solid dissolution in porous media consists of three dissolution regimes (uniform, compact, wormhole)—or patterns—that are established depending on the relative dominance of reaction rate, flow, and diffusion. In this work, we investigate the evolution of pore structure using numerical simulations during acid injection on tw...
Hypothesis: Understanding interfacial mass transfer during dissolution of gas in a liquid is vital for optimising large-scale carbon capture and storage operations. While the dissolution of CO2 bubbles in reservoir brine is a crucial mechanism towards safe CO2 storage, it is a process that occurs at the pore-scale and is not yet fully understood. D...
We present two novel Volume-of-Solid (VoS) formulations for micro-continuum simulation of mineral dissolution at the pore-scale. The traditional VoS formulation (VoS-ψ) uses a diffuse interface localization function ψ to ensure stability and limit diffusion of the reactive surface. The main limitation of this formulation is that accuracy is strongl...
The global commitment to achieve net-zero has led to increasing investment towards the production and usage of green hydrogen (H2).However, the massive quantity needed to match future demand will require new storage facilities. Underground storage of H2 is a potentially viable solution, but poses unique challenges due to the distinctive physical an...
Carbonate rocks have multiscale pore systems that are weakly understood. In this study, we use combined experimental, modeling, and pore space generation methods to tackle the impact of microporosity on the flow properties of Estaillades limestone. First, a nano-core from a microporous grain of Estaillades limestone was scanned using nanotomography...
GeoChemFoam is an open-source OpenFOAM-based numerical modelling toolbox that includes a range of custom packages to solve complex flow processes including multiphase transport with interface transfer, single-phase flow in multiscale porous media, and reactive transport with mineral dissolution. In this paper, we present GeoChemFoam’s novel numeric...
We present two novel Volume-of-Solid (VoS) formulations for micro-continuum simulation of mineral dissolution at the pore-scale. The traditional VoS formulation (VoS-psi) uses a diffuse interface localization function psi to ensure stability and limit diffusion of the reactive surface. The main limitation of this formulation is that accuracy is str...
Holistic understanding of multiphase reactive flow mechanisms such as CO 2 dissolution, multiphase displacement, and snap-off events is vital for optimisation of large-scale industrial operations like CO 2 sequestration, enhanced oil recovery, and geothermal energy. Recent advances in three-dimensional (3D) printing allow for cheap and fast manufac...
We present the ability to generate microscale and multiscale-porous media using affordable 3D printing technology to investigate fluid flow physics relevant to subsurface processes like CO2 storage. In this work we show two different applications: CO2 dissolution in the pore-scale and single-phase species transport in fractured porous media. This e...
GeoChemFoam is an open-source OpenFOAM-based toolbox that includes a range of additional packages that solve various flow processes from multiphase transport with interface transfer, to single-phase flow in multiscale porous media, to reactive transport with mineral dissolution. In this paper, we present a novel multiphase reactive transport solver...
We present a novel time-stepping method, called Operator Splitting with Capillary Relaxation (OSCAR), for efficient Volume-Of-Fluid simulations of capillary-dominated two-phase flow. OSCAR uses operator splitting methods to separate the viscous drag and the surface tension forces. Different time-steps are used for the viscous drag steps, controlled...
Holistic understanding of multiphase reactive flow mechanisms such as CO$_2$ dissolution, multiphase displacement, and snap-off events are vital for optimisation of large-scale industrial operations like CO$_2$ sequestration, enhanced oil recovery, and geothermal energy. Recent advances in three-dimensional (3D) printing allow for cheap and fast ma...
Studying the behavior of mineral dissolution has practical uses in Carbon Capture and Storage (CCS) and Improved Oil Recovery (IOR), and several numerical models are striving to simulate the process accurately. In this paper, we investigate the core-scale numerical model presented by Golfier et al. (J. Fluid Mecha., 2002), which uses the Darcy-Brin...
We present GeoChemFoam, a bespoke OpenFOAM toolbox for numerical investigation of multiphysics processes in pore structures. It includes several additional packages that solve a variety of flow processes. In this work, we highlight three applications of GeoChemFoam: multiphase multicomponent reactive transport induced by water injection in an oil-f...
The permeability of a pore structure is typically described by stochastic representations of its geometrical attributes. Database-driven numerical solvers for large model domains can only accurately predict large-scale flow behaviour when they incorporate upscaled descriptions of that structure. The upscaling is particularly challenging for rocks w...
During CO2 storage in depleted oil fields, under immiscible conditions, CO2 can be trapped in the pore space by capillary forces, providing safe storage over geological times - a phenomenon named capillary trapping. Synchrotron X-ray imaging was used to obtain dynamic three-dimensional images of the flow of the three phases involved in this process...
Carbonate rocks have particularly complex and multiscale pore systems which are weakly understood. In this study we use combined experimental, modelling, and pore space generation methods to tackle the impact of micro-porosity on the bulk flow properties of Estaillades limestone. First, a nano-core from a microporous grain of Estaillades Limestone...
Multiphase flow in permeable media is a complex pore-scale phenomenon, which is important in many natural and industrial processes. To understand the pore-scale dynamics of multiphase flow, we acquired time-series synchrotron X-ray micro-tomographic data at a voxel-resolution of 3.28 μm and time-resolution of 38 s during drainage and imbibition in...
We have experimentally investigated the impact of heterogeneity on the dissolution of two limestones, characterised by distinct degrees of flow heterogeneity at both the pore and core scales. The two rocks were reacted with reservoir-condition CO2-saturated brine at both scales and scanned dynamically during dissolution. First, 1 cm long 4 mm diame...
Significance
The movement of immiscible fluids through permeable media occurs in many settings, including oil and water flow through rock. Here we present observations of a previously unidentified type of steady-state flow behavior that we term “dynamic connectivity.” We demonstrate that flow of the nonwetting phase occurs through a network of conn...
Understanding the pore-scale dynamics of two-phase fluid flow in permeable media is important in many processes such as water infiltration in soils, oil recovery, and geo-sequestration of CO2. The two most important processes that compete during the displacement of a non-wetting fluid by a wetting fluid are pore-filling or piston-like displacement...
We study the impact of brine acidity and initial pore structure on the dynamics of fluid/solid reaction at high Péclet numbers and low Damköhler numbers. A laboratory μ-CT scanner was used to image the dissolution of Ketton, Estaillades, and Portland limestones in the presence of CO2-acidified brine at reservoir conditions (10 MPa and 50°C) at two...
Understanding how to upscale pore scale rock-fluid interaction processes for predictive modelling poses a significant challenge to the carbon storage and petroleum industries. We have designed a set of experiments to investigate the impact of scale and pore-space heterogeneity on the dissolution of two carbonates at both the pore and core scales. T...
Geologic CO2 storage has been identified as key to avoiding dangerous climate change. Storage in oil reservoirs dominates the portfolio of existing projects due to favorable economics. However, in an earlier related work, Al-Menhali and Krevor (2016), it was identified that an important trapping mechanism, residual trapping, is weakened in rocks wi...
This thesis presents the first dynamic imaging of fluid/rock reaction using x-ray microtomography (μ-CT) and focuses on three series of experiments: (1) imaging a homogenous carbonate during dissolution using a laboratory scanner; (2) imaging heterogeneous carbonates at multiple flow rates using a synchrotron pink beam; (3) imaging the same rocks u...
We investigate the impact of initial pore structure and velocity field heterogeneity on the dynamics of fluid/solid reaction at high Péclet numbers (fast flow) and low Damköhler number (relatively slow reaction rates). The Diamond Lightsource Pink Beam was used to image dissolution of Estaillades and Portland limestones in the presence of CO2-satur...
Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve geologic seals and allow CO2 to escape. However, the dissolution processes at reservoir conditions are poorly understood. Thus, time-resolved experiments are needed to observe and predict the nature a...
Fast synchrotron-based X-ray microtomography was used to image the injection of super-critical CO2 under subsurface conditions into a brine-saturated carbonate sample at the pore-scale with a voxel size of 3.64μm and a temporal resolution of 45 s. Capillary pressure was measured from the images by finding the curvature of terminal menisci of both c...
Large scale faults are important structural elements within many conventional clastic reservoirs, acting as potential conduits, baffles or barriers to hydrocarbon or CO2 migration. Though inconspicuous within most seismic tomography datasets, smaller subsidiary faults, commonly within the damage zones of parent structures, may also play an importan...
Quantifying CO2 transport and average effective reaction rates in the subsurface is essential to assess the risks associated with underground carbon capture and storage. We use X-ray microtomography to investigate dynamic pore structure evolution in situ at temperatures and pressures representative of underground reservoirs and aquifers. A 4 mm dia...
The estimation of differential time delays between similar but noisy time series by cross-correlation is an important component of many data processing applications. In many cases, delays are determined for every pair of time series drawn from a large set of them. For instance, modern earthquake location techniques utilize the differential delays b...
Four carbonate rock types were studied, two relatively homogeneous carbonates, Ketton and Mt. Gambier, and two very heterogeneous carbonates, Estalliades and Portland Basebed. Each rock type was imaged using dynamic x-ray microtomography under the same reservoir and flow conditions to gain insight into the impact of heterogeneity. A 4-mm carbonate...
Carbon sequestration in deep geologic formations is one way of reducing
anthropogenic CO2 emissions. Successful sequestration requires minimal
CO2 leakage rates in order to mitigate possible negative impacts to
overlying aquifers and human populations. Much work has been done on CO2
migration within the injection zone. However, leakage rates throug...
Storage of anthropogenic CO2 in depleted oil fields and deep saline
aquifers has been presented as a feasible method of averting climate
change. The longest-term storage mechanism of CO2 in underground
reservoirs is through mineral trapping. Here we use the multiphase
reactive transport finite difference 3-D reservoir simulator PFLOTRAN,
developed...
Success of long-term CO2 storage in geologic carbon repositories will depend in part on caprock integrity. An effective caprock possesses low permeabilty, such that capillary entry pressures impeding vertical CO2 migration are high, and contain few open fractures. In cases where CO2 leakage through the caprock does occur, contamination of overlying...