Julien Maes

• Doctor of Philosophy
• Research Fellow at Heriot-Watt University

Simulating reactive dissolution of solid minerals in porous media has many subsurface applications, including carbon capture and storage (CCS), geothermal systems and oil & gas recovery. As traditional direct numerical simulators are computationally expensive, it is of paramount importance to develop faster and more efficient alternatives. Deep-lea...

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....

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...

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...

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...

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...

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 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...

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...

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...

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...

Computational microfluidics for geosciences is the third leg of the scientific strategy that includes microfluidic experiments and high-resolution imaging for deciphering coupled processes in geological porous media. This modeling approach solves the fundamental equations of continuum mechanics in the exact geometry of porous materials. Computation...

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...

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...

Multiphase multispecies transport is an essential field of study for a wide range of applications including bubble reactors and CO2 stor- age in the subsurface. Modelling of these processes is challeng- ing due to the discontinuity of material properties, making accu- rate modelling of mass transfer at reactive interface difficult. Maes and Soulain...

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...

Imbibition is an important process encountered in many porous media applications. At the pore scale, pore network models (PNM) are computationally efficient and can model drainage accurately. However, using PNM to model imbibition still remains a challenge due to the complexities encountered in understanding pore-scale flow phenomena related to por...

This paper presents a novel unified single-field formulation for Volume-Of-Fluid simulation of interfacial mass transfer with local volume changes. By comparison with the previous models referred as Continuous Species Transfer in the literature, our improved model uses a single-field formulation of the local mass transfer across the interface, enab...

Understanding pore-scale flow and transport processes is important for understanding flow and transport within rocks on a larger scale. Flow experiments on small-scale micromodels can be used to experimentally investigate pore-scale flow. Current manufacturing methods of micromodels are costly and time consuming. 3D printing is an alternative metho...

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...

The simulation of multi-phase flow at low capillary numbers (Ca) remains a challenge. Approximate computations of the capillary forces tend to induce parasitic currents (PC) around the interface. These PC induce additional viscous dissipation and shear forces that potentially lead to wrong calculations of the general flow dynamics. Here, we focus o...

We present a new compressive scheme to simulate species transfer across fluid interfaces using the Volume-Of-Fluid method. We show that at high Péclet numbers, the standard Continuous Species Transfer (CST) generates large numerical diffusion in the phase concentration that can lead to inaccurate simulation of interface exchanges in a two-phase sys...

Laboratory experiments have shown that oil production from sandstone and carbonate reservoirs by waterflooding could be significantly increased by manipulating the composition of the injected water (e.g. by lowering the ionic strength). Recent studies suggest that a change of wettability induced by a change in surface charge is likely to be one of...

Comparison of VOF and PFM approach for simulation of non-wetting slug in a microchannel

Numerical simulation of wettability change during low-salinity flooding in simple micro-models using a coupled two-phase transport / surface complexation model

The In-Situ Upgrading (ISU) of heavy oil and oil shale is investigated. We develop a mathematical model for the process and identify the full set of dimensionless numbers describing the model. We demonstrate that for a model with fluid components (gas and oil), solid components and k chemical reactions, the model was represented by dimensionless nu...

Comparison between VOF and phase-Field for two-phase flow in simple micro-models

Numerical model coupling two-phase flow, reactive transport and contact angle evolution to study wettability change in 2D micro-models

The in-situ upgrading (ISU) of bitumen and oil shale is a very challenging process to model numerically because of the large number of components that need to be modelled using a system of equations that are both highly non-linear and strongly coupled. Operator splitting methods are one way of potentially improving computational performance. Each n...

Using VOF for reactive transport with OpenFOAM

The modelling of In-Situ Upgrading of heavy oil is complex as various physical and chemical phenomena need to be represented. In this process, a tight pattern of electrical heater wells is used to bring the formation to a high temperature so that the heavy oil decomposes through a series of pyrolysis reactions into lighter liquid and gas components...

The In-Situ Upgrading (ISU) of bitumen and oil shale is a very challenging process to model numerically because a large number of components need to be modelled using a system of equations that are both highly non-linear and strongly coupled. Operator splitting methods are one way of potentially improving computational performance. Each numerical o...

The modelling of heat and mass flow through porous media in the presence of pyrolysis is complex because various physical and chemical phenomena need to be represented. In addition to the transport of heat by conduction and convection, and the change of properties with varying pressure and temperature, these processes involve transport of mass by c...

In terms of the robustness and accuracy of the TAIM stability limits, our analysis and computational results indicate that honoring the divergence of the total-velocity in the linearized system of coupled mass and energy conservation equations is more important than accounting for the rock and fluids compressibility effects. Moreover, we demonstrat...

We present new linear-stability criteria for the Thermal Adaptive Implicit Method (TAIM) for thermal multiphasic compositional displacement. The analysis is applied to the mass and energy equations. Moncorgé and Tchelepi's work (2009) is based on the assumption of divergence-free total velocity, and accounts for compressibility effects. Our analysi...