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Fluids in Porous Media

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Materials Chemistry".

Deadline for manuscript submissions: closed (31 July 2020) | Viewed by 28406

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Dr. David Faux

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Guest Editor

University of Surrey, Guildford, UK
Interests: nuclear magnetic resonance; NMR relaxometry; mathematical modelling; cement-based materials; plaster; clays; wood; zeolites; molecular dynamics modelling; Monte Carlo modelling; paramagnetic image contrast agents; water; rheology; Lattice-Boltzmann modelling

Special Issue Information

Dear Colleagues,

Porous materials come in a wide variety of different forms and pervade our everyday lives. For example, buildings are constructed using cement- and clay-based materials, or wood. Household products such as toothpaste (silica), washing powder (zeolites) and diapers (hydrogels), noise and heat insulators, and filtration systems also rely on porous materials. The characterisation of rock is essential for hydrocarbon recovery viability assessment, and clays may be useful as potential radioactive waste storage sites. Polymer systems have applications in fuel cells, and protein systems and tissue have applications in medicine, pharmacy research and biomedical engineering.

For each of these systems, it is vital to understand the properties of the fluid contained within the porous media. This is intrinsic to the understanding of their properties and hence to the development of new and improved products. Hence, much highly-significant research is being undertaken in a wide variety of porous systems. For example, cement production is the third largest contributor to CO₂ emissions worldwide, and understanding the nanoscale behaviour of water within cement products is pivotal to designing new products with a lower carbon footprint and improved durability.

Nonetheless, porous media are notoriously complex and obtaining reliable data on pore structure and the fluid contained in the pores is a significant challenge. Experimental techniques such as nuclear magnetic resonance (NMR) imaging are valuable, and NMR relaxometry experiments can yield information on the nanoscale behaviour of fluids. Small-angle X-ray scattering and quasi-elastic or small-angle neutron scattering have made important contributions to this field of research as have more conventional measurements used to estimate porosity, tortuosity and permeability.

Many of these experimental techniques are used in tandem with theoretical or computational modelling to infer the dynamics and nano-microstructure of a fluid and its confining matrix. Computer simulations are used at the atomic scale through ab initio quantum mechanical calculations, at the nanoscale through molecular dynamics, at the nano-to-micro scales through Monte Carlo methods, at the macro-scale through Lattice-Boltzmann, and through conventional continuum-mechanics flow modelling at larger scales.

This Special Issue aims to cover recent progress and trends in the understanding of the behaviour of fluids in porous media. This may focus on experimental techniques, advances in understanding the specific porous materials, theoretical developments and applications of computer simulations.

Submissions on, but not limited, to the topics listed below are welcome. Types of contributions to this Special Issue may include full research articles, short communications, and reviews focusing on the properties of fluid in porous media.

Dr. David Faux
Guest Editor

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Keywords

experimental techniques for probing fluids in porous material
computer modelling of fluid in porous media
cement-based materials such as cement paste, mortar, concrete and plaster
water and hydrocarbon fluid in rock
porous silica-based material
soft porous material
metal–organic systems
polymeric systems

Published Papers (10 papers)

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Research

22 pages, 7775 KiB

Open AccessArticle

Mass and Heat Transfer of Thermochemical Fluids in a Fractured Porous Medium

by Murtada Saleh Aljawad, Mohamed Mahmoud and Sidqi A Abu-Khamsin

Molecules 2020, 25(18), 4179; https://doi.org/10.3390/molecules25184179 - 12 Sep 2020

Cited by 6 | Viewed by 2203

Abstract

The desire to improve hydraulic fracture complexity has encouraged the use of thermochemical additives with fracturing fluids. These chemicals generate tremendous heat and pressure pulses upon reaction. This study developed a model of thermochemical fluids’ advection-reactive transport in hydraulic fractures to better understand thermochemical fluids’ penetration length and heat propagation distance along the fracture and into the surrounding porous media. These results will help optimize the design of this type of treatment. The model consists of an integrated wellbore, fracture, and reservoir mass and heat transfer models. The wellbore model estimated the fracture fluid temperature at the subsurface injection interval. The integrated model showed that in most cases the thermochemical fluids were consumed within a short distance from the wellbore. However, the heat of reaction propagated a much deeper distance along the hydraulic fracture. In most scenarios, the thermochemical fluids were consumed within 15 ft from the fracture inlet. Among other design parameters, the thermochemical fluid concentration is the most significant in controlling the penetration length, temperature, and pressure response. The model showed that a temperature increase from 280 to 600 °F is possible by increasing the thermochemical concentration. Additionally, acid can be used to trigger the reaction but results in a shorter penetration length and higher temperature response. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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16 pages, 4149 KiB

Open AccessArticle

Effects of Foam Microbubbles on Electrical Resistivity and Capillary Pressure of Partially Saturated Porous Media

by Abdulrauf R. Adebayo, Abubakar Isah, Mohamed Mahmoud and Dhafer Al-Shehri

Molecules 2020, 25(15), 3385; https://doi.org/10.3390/molecules25153385 - 26 Jul 2020

Cited by 14 | Viewed by 3036

Abstract

Laboratory measurements of capillary pressure (P_c) and the electrical resistivity index (RI) of reservoir rocks are used to calibrate well logging tools and to determine reservoir fluid distribution. Significant studies on the methods and factors affecting these measurements in rocks containing oil, gas, and water are adequately reported in the literature. However, with the advent of chemical enhanced oil recovery (EOR) methods, surfactants are mixed with injection fluids to generate foam to enhance the gas injection process. Foam is a complex and non-Newtonian fluid whose behavior in porous media is different from conventional reservoir fluids. As a result, the effect of foam on P_c and the reliability of using known rock models such as the Archie equation to fit experimental resistivity data in rocks containing foam are yet to be ascertained. In this study, we investigated the effect of foam on the behavior of both P_c and RI curves in sandstone and carbonate rocks using both porous plate and two-pole resistivity methods at ambient temperature. Our results consistently showed that for a given water saturation (S_w), the RI of a rock increases in the presence of foam than without foam. We found that, below a critical S_w, the resistivity of a rock containing foam continues to rise rapidly. We argue, based on knowledge of foam behavior in porous media, that this critical S_w represents the regime where the foam texture begins to become finer, and it is dependent on the properties of the rock and the foam. Nonetheless, the Archie model fits the experimental data of the rocks but with resulting saturation exponents that are higher than conventional gas–water rock systems. The degree of variation in the saturation exponents between the two fluid systems also depends on the rock and fluid properties. A theory is presented to explain this phenomenon. We also found that foam affects the saturation exponent in a similar way as oil-wet rocks in the sense that they decrease the cross-sectional area of water available in the pores for current flow. Foam appears to have competing and opposite effects caused by the presence of clay, micropores, and conducting minerals, which tend to lower the saturation exponent at low S_w. Finally, the P_c curve is consistently lower in foam than without foam for the same S_w. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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13 pages, 1580 KiB

Open AccessArticle

Analysis of the Stochastic Quarter-Five Spot Problem Using Polynomial Chaos

by Hesham AbdelFattah, Amnah Al-Johani and Mohamed El-Beltagy

Molecules 2020, 25(15), 3370; https://doi.org/10.3390/molecules25153370 - 24 Jul 2020

Cited by 1 | Viewed by 2181

Abstract

Analysis of fluids in porous media is of great importance in many applications. There are many mathematical models that can be used in the analysis. More realistic models should account for the stochastic variations of the model parameters due to the nature of the porous material and/or the properties of the fluid. In this paper, the standard porous media problem with random permeability is considered. Both the deterministic and stochastic problems are analyzed using the finite volume technique. The solution statistics of the stochastic problem are computed using both Polynomial Chaos Expansion (PCE) and the Karhunen-Loeve (KL) decomposition with an exponential correlation function. The results of both techniques are compared with the Monte Carlo sampling to verify the efficiency. Results have shown that PCE with first order polynomials provides higher accuracy for lower (less than 20%) permeability variance. For higher permeability variance, using higher-order PCE considerably improves the accuracy of the solution. The PCE is also combined with KL decomposition and faster convergence is achieved. The KL-PCE combination should carefully choose the number of KL decomposition terms based on the correlation length of the random permeability. The suggested techniques are successfully applied to the quarter-five spot problem. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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22 pages, 10430 KiB

Open AccessArticle

A Novel Approach to Improve Acid Diversion in Carbonate Rocks Using Thermochemical Fluids: Experimental and Numerical Study

by Mustafa Ba Alawi, Amjed Hassan, Murtada Saleh Aljawad, Muhammad Shahzad Kamal, Mohamed Mahmoud and Ayman Al-Nakhli

Molecules 2020, 25(13), 2976; https://doi.org/10.3390/molecules25132976 - 28 Jun 2020

Cited by 12 | Viewed by 2588

Abstract

The distribution of acid over all layers of interest is a critical measure of matrix acidizing efficiency. Chemical and mechanical techniques have been widely adapted for enhancing acid diversion. However, it was demonstrated that these often impact the formation with damage after the acid job is completed. This study introduces, for the first time, a novel solution to improve acid diversion using thermochemical fluids. This method involves generating nitrogen gas at the downhole condition, where the generated gas will contribute in diverting the injected acids into low-permeability formations. In this work, both lab-scale numerical and field-scale analytical models were developed to evaluate the performance of the proposed technique. In addition, experimental measurements were carried out in order to demonstrate the application of thermochemical in improving the acid diversion. The results showed that a thermochemical approach has an effective performance in diverting the injected acids into low-permeability rocks. After treatment, continuous wormholes were generated in the high-permeability rocks as well as in low-permeability rocks. The lab-scale model was able to replicate the wormholing impact observed in the lab. In addition, alternating injection of thermochemical and acid fluids reduced the acid volume 3.6 times compared to the single stage of thermochemical injection. Finally, sensitivity analysis indicates that the formation porosity and permeability have major impacts on the acidizing treatment, while the formations pressures have minor effect on the diversion performance. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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18 pages, 7577 KiB

Open AccessArticle

Exposure Time Impact on the Geomechanical Characteristics of Sandstone Formation during Horizontal Drilling

by Hany Gamal, Salaheldin Elkatatny, Abdulazeez Abdulraheem and Abdulaziz Al Majed

Molecules 2020, 25(11), 2480; https://doi.org/10.3390/molecules25112480 - 27 May 2020

Cited by 11 | Viewed by 2644

Abstract

The rock geomechanical properties are the key parameters for designing the drilling and fracturing operations and for programing the geomechanical earth models. During drilling, the horizontal-section drilling fluids interact with the reservoir rocks in different exposure time, and to date, there is no comprehensive work performed to study the effect of the exposure time on the changes in sandstone geomechanical properties. The objective of this paper is to address the exposure time effect on sandstone failure parameters such as unconfined compressive strength, tensile strength, acoustic properties, and dynamic elastic moduli while drilling horizontal sections using barite-weighted water-based drilling fluid. To simulate the reservoir conditions, Buff Berea sandstone core samples were exposed to the drilling fluid (using filter press) under 300 psi differential pressure and 200 °F temperature for different exposure times (up to 5 days). The rock characterization and geomechanical parameters were evaluated as a function of the exposure time. Scratch test was implemented to evaluate rock strength, while ultrasonic pulse velocity was used to obtain the sonic data to estimate dynamic elastic moduli. The rock characterization was accomplished by X-ray diffraction, nuclear magnetic resonance, and scanning electron microscope. The study findings showed that the rock compression and tensile strengths reduced as a function of exposure time (18% and 19% reduction for tensile strength and unconfined compression strength, respectively, after 5 days), while the formation damage displayed an increasing trend with time. The sonic results demonstrated an increase in the compressional and shear wave velocities with increasing exposure time. All the dynamic elastic moduli showed an increasing trend when extending the exposure time except Poisson’s ratio which presented a constant behavior after 1 day. Nuclear magnetic resonance results showed 41% porosity reduction during the five days of mud interaction. Scanning electron microscope images showed that the rock internal surface topography and internal integrity changed with exposure time, which supported the observed strength reduction and sonic variation. A new set of empirical correlations were developed to estimate the dynamic elastic moduli and failure parameters as a function of the exposure time and the porosity with high accuracy. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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16 pages, 3804 KiB

Open AccessArticle

Experimental Investigation of the Fluidization Reduction Characteristics of Iron Particles Coated with Carbon Powder under Pressurized Conditions

by Qiyan Xu, Zhiping Li and Zhanghan Gu

Molecules 2020, 25(8), 1810; https://doi.org/10.3390/molecules25081810 - 15 Apr 2020

Cited by 3 | Viewed by 2020

Abstract

The purpose of this study was to comprehensively analyze the effects of the carbon powder coating mass fraction, pressure, reduction temperature, reduction time, gas linear velocity, and particle size on fluidization reduction. Brazilian fine iron ore particles were the experimental object, and reduction experiments were performed under added carbon powder coating and pressure conditions. A six-factor, three-level orthogonal experiment method was used to obtain the optimal operating conditions and investigate the adhesion and inhibition mechanisms of fine iron ore during reduction. The experimental results show that with the addition of a carbon powder coating, an appropriate increase in pressure can increase the metallization rate, improve the fluidization state, and reduce the sticking ratio. The optimal operating conditions for pure hydrogen to reduce Brazilian fine iron ore was found to be a reduction temperature of 923–1023 K, the linear velocity of the reducing gas was 0.6 m/s, the reducing time was 30–50 min, the reducing pressure was 0.25 MPa, the mass content of the coated carbon powder was 2–6% (accounting for the mass of the mineral powder), and the particle size of the carbon powder was 4–7 µm. Iron whiskers cohesion and agglomeration were the main reasons for the adhesion of ore powder particles. It was found that carbon powder coating can effectively change the morphology of metal iron, as metal iron generates spherical particles around the carbon powder to improve the fluidization state. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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9 pages, 2275 KiB

Open AccessArticle

The Effect of Silica Fume and Organosilane Addition on the Porosity of Cement Paste

by Andrea Crețu, Carlos Mattea, Siegfried Stapf and Ioan Ardelean

Molecules 2020, 25(8), 1762; https://doi.org/10.3390/molecules25081762 - 11 Apr 2020

Cited by 6 | Viewed by 2384

Abstract

The present work systematically investigates the influence of silica fume and organosilane addition on the hydration dynamics and the capillary pore formation of a cement paste. The cement samples were prepared with two water-to-cement ratios with increasing amounts of silica fume and of (3-Aminopropyl)triethoxysilane (APTES) organosilane. Low-field ¹H nuclear magnetic resonance (NMR) relaxation measurements were performed during the hydration of the samples and after hydration, in order to reveal the dynamics of water molecules and the pore distribution. Increasing concentrations of silica fume impact the perceived hydration dynamics through the addition of magnetic impurities to the pore solution. However, there is a systematic change in the capillary pore size distribution with an increase in silica fume concentration. The results also show that the addition of APTES majorly affects the hydration dynamics, by prolonging the dormancy and hardening stages. While it does not influence the pore size distribution of capillary pores, it prevents cyclohexane from saturating the capillary pores. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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17 pages, 2852 KiB

Open AccessArticle

Effect of Initial Conformation on the Starch Biopolymer Film Formation Studied by NMR

by Sushanta Ghoshal, Carlos Mattea, Paul Denner and Siegfried Stapf

Molecules 2020, 25(5), 1227; https://doi.org/10.3390/molecules25051227 - 9 Mar 2020

Cited by 9 | Viewed by 3305

Abstract

The formation of a rigid porous biopolymer scaffold from aqueous samples of 1% w/v (suspension) and 5% w/v (gel) corn starch was studied using optical and nuclear magnetic resonance (NMR) techniques. The drying process of these systems was observed using a single-sided NMR scanner by application of the Carr–Purcell–Meiboom–Gill pulse sequence at different layer positions. The echo decays were analyzed and spin–spin relaxation times (T₂) were obtained for each layer. From the depth dependent T₂ relaxation time study, it was found that the molecular mobility of water within the forming porous matrix of these two samples varied notably at different stages of film formation. At an intermediate stage, a gradual decrease in mobility of the emulsion sample towards the air–sample interface was observed, while the gel sample remained homogeneous all along the sample height. At a later stage of drying, heterogeneity in the molecular dynamics was observed in both samples showing low mobility at the bottom part of the sample. A wide-angle X-ray diffraction study confirmed that the structural heterogeneity persisted in the final film obtained from the 5% corn starch aqueous sample, whereas the film obtained from the 1% corn starch in water was structurally homogeneous. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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21 pages, 1018 KiB

Open AccessArticle

Unsteady Radiative Natural Convective MHD Nanofluid Flow Past a Porous Moving Vertical Plate with Heat Source/Sink

by Talha Anwar, Poom Kumam, Zahir Shah, Wiboonsak Watthayu and Phatiphat Thounthong

Molecules 2020, 25(4), 854; https://doi.org/10.3390/molecules25040854 - 14 Feb 2020

Cited by 22 | Viewed by 3472

Abstract

In this research article, we investigated a comprehensive analysis of time-dependent free convection electrically and thermally conducted water-based nanofluid flow containing Copper and Titanium oxide (Cu and

{TiO}_{2}

) past a moving porous vertical plate. A uniform transverse magnetic field is imposed [...] Read more.

{TiO}_{2}

) past a moving porous vertical plate. A uniform transverse magnetic field is imposed perpendicular to the flow direction. Thermal radiation and heat sink terms are included in the energy equation. The governing equations of this flow consist of partial differential equations along with some initial and boundary conditions. The solution method of these flow interpreting equations comprised of two parts. Firstly, principal equations of flow are symmetrically transformed to a set of nonlinear coupled dimensionless partial differential equations using convenient dimensionless parameters. Secondly, the Laplace transformation technique is applied to those non-dimensional equations to get the close form exact solutions. The control of momentum and heat profile with respect to different associated parameters is analyzed thoroughly with the help of graphs. Fluid accelerates with increasing Grashof number (Gr) and porosity parameter (K), while increasing values of heat sink parameter (Q) and Prandtl number (Pr) drop the thermal profile. Moreover, velocity and thermal profile comparison for Cu and

{TiO}_{2}

-based nanofluids is graphed. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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20 pages, 6318 KiB

Open AccessArticle

Brownian Motion and Thermophoresis Effects on MHD Three Dimensional Nanofluid Flow with Slip Conditions and Joule Dissipation Due to Porous Rotating Disk

by Nasser Aedh Alreshidi, Zahir Shah, Abdullah Dawar, Poom Kumam, Meshal Shutaywi and Wiboonsak Watthayu

Molecules 2020, 25(3), 729; https://doi.org/10.3390/molecules25030729 - 7 Feb 2020

Cited by 39 | Viewed by 3462

Abstract

This paper examines the time independent and incompressible flow of magnetohydrodynamic (MHD) nanofluid through a porous rotating disc with velocity slip conditions. The mass and heat transmission with viscous dissipation is scrutinized. The proposed partial differential equations (PDEs) are converted to ordinary differential equation (ODEs) by mean of similarity variables. Analytical and numerical approaches are applied to examine the modeled problem and compared each other, which verify the validation of both approaches. The variation in the nanofluid flow due to physical parameters is revealed through graphs. It is witnessed that the fluid velocities decrease with the escalation in magnetic, velocity slip, and porosity parameters. The fluid temperature escalates with heightening in the Prandtl number, while other parameters have opposite impacts. The fluid concentration augments with the intensification in the thermophoresis parameter. The validity of the proposed model is presented through Tables. Full article

(This article belongs to the Special Issue Fluids in Porous Media)

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