Presentation materials
In this talk, we consider a two-phase Darcy flow in a fractured and deformable porous medium for which the fractures are described as a network of planar surfaces leading to so-called hybrid-dimensional models. Fractures are assumed open and filled by the fluids, and small deformations with a linear elastic constitutive law are considered in the matrix. At matrix-fracture interfaces, phase...
Coupled thermal-hydrological-mechanical-chemical (THMC) processes can significantly impact fracture permeability, immediately influencing the productivity/injectivity of fracture-dominated reservoirs, associated with geothermal energy extraction, hydrocarbon production, nuclear waste disposal, and geologic storage of carbon dioxide (CO2). It is, therefore, necessary to investigate the THMC...
A model for homogenized flow in porous media with large inhomogeneities is presented. Classical homogenization relies on representative elementary volumes (REV) large enough that asymptotic macroscopic parameters, e.g. effective permeabilites, can be employed to describe the expected or mean behavior. In this way, Darcy's law, which describes the relationship between macroscopic pressure...
Although significant progress has been made in the tight gas exploration and development, there is still a limited understanding of the fluid charging and hydrocarbon accumulation in the sweet spot. In this study, a novel method is proposed to generate the stochastically constructed porous media which represents the transition region between tight surrounding sandstone and sweet spot. Based on...
Fractures can provide principal fluid flow pathways in the Earth’s crust, making them a critical feature influencing subsurface geoenergy applications, such as the storage of anthropogenic waste, emissions or energy. In such scenarios, fluid-conductive fault and fracture networks are synonymous with two-phase flow, due to the injection of an additional fluid (e.g. CO2) into an already...
Analysis of consistent experimental sets of hydro-mechanical data recorded during hydraulic experiments on single fractures or fractured reservoirs require a consistent numerical model to determine fracture properties with a high accuracy. Hence, this work briefly discusses the derivation and numerical implementation of a consistent, fully coupled hydro-mechanical model for flow in deformable...
Reduced Basis (RB) methods are well-known and widely used techniques applied to complex parameterized simulation problems to obtain reliable discrete results for a particular choice of parameters, largely reducing the computational time to obtain the numerical solutions.
Flow simulations in underground fractured media seems to be a perfect application for the RB framework, due to the...
It remains challenging to fully understand the granular transport mechanisms in confined geometries like fractured media. Here, by performing massively parallel simulations based on a coupled computational fluid dynamics and discrete element method (CFD-DEM) approach, we systematically investigate the particle transport patterns and mechanisms driven by fluid flow in both smooth and rough...
In this presentation we introduce an innovative mathematical model that is able to describe chemical processes that may occur in fractured porous media. A solute is carried by a fluid in the porous medium, that reacting precipitates forming a salt that might alter the physical properties of the system, creating zone of low flow. Conversely, if the salt dissolves it might open up new pathways...
The thermal treatment of rocks is a frequently used method to initiate micro-cracks. This is done to study experimentally different physical phenomena related to micro-cracks. The effect of micro-cracks on the effective macroscopic properties can be quantified, for instance, by wave propagation measurements or porosity measurements. Micro X-Ray Computed Tomography (µXRCT), as a noninvasive...
This work provides new experimental evidence regarding two-phase fluid flow in damaged porous media. The results aim to provide novel cases towards leakage rate modelling dedicated to the well-prediction of reliability and durability of the pressurised concrete structures such as nuclear containment buildings.
Previous experimental works on the structural scale, e.g. reinforced concrete...
In order to model mechanics of porous media, the elastoplastic behaviour of materials, such as rocks and soils, plays an important role. In this work, we study Virtual Element Methods for 3D elastoplastic simulations. We focus on the equations that characterize the elastoplastic 3D model in the framework of small deformations theory. We especially deal with the Mohr-Coulomb plasticity model,...
The recoverable natural gas in carbonate reservoirs account for 45% of the total gas reserves. However, the physical heterogeneity of carbonate reservoirs is strong, and the fractures play a strong role in flow controlling. Therefore, gas-water two-phase flow in fractured carbonates is the key to hydrodynamic modeling of gas reservoir development with bottom and edge water. Here, using in situ...
In the context of two-phase flows in porous media, Tyagi and Jenny (2008) have discussed the potential of particle-based schemes to simulate macroscale transport using the information of microscale flow dynamics. However, with the uncertainties in heterogeneity characterization and additionally, modeling challenges, obtaining a well-informed picture of microscale dynamics is not feasible....
The carbonate reservoir is one of the important reservoir types, while they are different from the conventional reservoirs. They are very complex and are characterized by serious heterogeneity and multi-scales, the porosity scale is from the millimeter level to the meter level, thus there is not only the Darcy flow but also nonDarcy flow in the subsurface. It means it is hard to simulate the...
Numerical modelling of fluid flow and heat transport in geothermal reservoirs can be very challenging due to the need of modelling several length-scales simultaneously that control the flow behaviour. The lenght-scales to consider typically go from fractures (millimetre-scale) and wells (metre-scale) to facies architecture and faults (kilometre-scale). The usual approach for modelling...
We present a higher-order finite element (FE) reactive transport model for unstructured and fractured grids. We use an advanced research simulator (Osures) for flow and transport in subsurface fractured porous media, which models the convection, gravity, mechanical dispersion, Fickian diffusion, Nernst-Planck (electrochemical) diffusion, and capillarity as driving forces. Fluid flow is modeled...
In finite volume methods (FVM) with explicit time integration, the Courant-Friedrichs-Levy (CFL) number needs to be below a critical value in order to ensure stability and accurate time integration. The CFL criterion provides an upper bound of the time step for every grid cell. In conventional methods, where the same time step is used for all grid cells, the lowest value of this upper bound is...
Emulsions flow in porous media has been found to play an important role in hydrocarbon recovery, especially in enhanced oil recovery (EOR) for conformance control in shale oil recovery where mixed oil and water flow through fractures. However, the mechanisms ruling emulsions flow remain elusive with studies mostly limited to empirical correlations. Recent development of microfluidic...
Strength and stability of rocks are essential information [1] for engineers and operators working in the field like petroleum production, geothermal installation and underground CO2 storage. During operations, sometimes fractures open-up at the well-boundaries and fractures are mostly seen as “disturbing elements” for the stability of wells and well-operations. It is a real challenge to plan a...
The stimulation of crack growth in quartz and siliceous materials by hydraulic fluids or carbon dioxide (CO
Fracture systems exists in carbonate oil reservoirs with either natural or artificial origins. The permeability contrast between the fracture and the matrix makes most injection fluids bypass the matrix and result in low matrix oil recovery, especially for low-permeability matrices. Low IFT gas and foam injections can enhance oil recovery by decreasing capillary pressure and diverting gas from...
The long-term heat extraction from enhanced geothermal systems (EGSs) highly depends on the flow and transport characteristics in the underlying fracture networks connecting injection and production wells. Tracer testing is a powerful diagnostic tool for subsurface fracture characterization. However, interpreting the obtained tracer data for long-term thermal performance prediction is not a...
An ideal CO2 storage site needs to be able to contain a large volume of CO2 without any significant leakage through the caprock seal. Aside from legacy wells, (sub-seismic) faults and associated fractured damage zones form a potential containment risk. A well-connected fracture network can increase the permeability and decrease the capillary barrier of the caprock, rendering them to be...
Flow in fractured porous media is in part controlled by the fluid pressure within the fracture, which is typically modelled by assuming planar fracture surfaces. However, experimental data has shown that the geometry of non-planar, i.e. rough fracture surfaces impacts both permeability and its dependency on stress. Various (semi-)analytical and numerical methods have been developed to describe...
Natural occurring fractures can dominate fluid flow in subsurface rock and thus be crucial for engineering operations such as energy recovery and waste disposal. The fractures occur on multiple length scale with no scale separation, forming a challenge for their incorporation into mathematical models for fluid flow [1], as well as for discretizations.
Among the several classes of...
Predicting and controlling fractures in porous materials has posed many challenges in understanding the long-term performance of such complex systems. Geological systems such as CO2 sequestration, geothermal, waste repositories, oil and gas recoveries, are examples of natural porous materials, where fracture and damage play significant roles. In many of these systems, chemical alterations lead...
The complex interplay of injected reactive fluid with shale minerals and resident formation brine has a potentially significant role in the rapid decline of hydrocarbon production following fracturing operations. A sudden inflow of reactive fluid into brine-bearing shales that are initially in equilibrium causes mineral dissolution and precipitation reactions. These reactions contribute...
