Pore-scale Model Research Articles

Understanding the role of wettability distribution on pore-filling and displacement patterns in a homogeneous structure via quasi 3D pore-scale modelling

Most numerical simulation studies have focused on the effect of homogenous wettability on fluid flow dynamics; however, most rocks display spatially heterogeneous wettability. Therefore, we have used direct numerical simulations (DNS) to investigate wettability heterogeneity at pore-scale. We have built a quasi-3D pore-scale model and simulated two-phase flow in a homogenous porous media with homogenous and heterogeneous wettability distributions. Five different heterogeneous wettability patterns were used in this study. We observed that heterogenous wettability significantly affects the evolution of fluid interface, trapped saturation, and displacement patterns. Wettability heterogeneity results in fingering and specific trapping patterns which do not follow the flow behaviour characteristic of a porous medium with homogenous wettability. This flow behaviour indicates a different flow regime that cannot be estimated using homogenous wettability distributions represented by an average contact angle. Moreover, our simulation results show that certain spatial configurations of wettability heterogeneity at the microscale, e.g. being perpendicular to the flow direction, may assist the stability of the displacement and delay the breakthrough time. In contrast, other configurations such as being parallel to the flow direction promote flow instability for the same pore-scale geometry.

Pore network and Darcy scale modelling of DNAPL remediation using ethanol flushing: Study of physical properties in DNAPL remediation

Co-solvent flushing into contaminated soils is one of the most effective techniques for Dense Non-Aqueous Phase Liquid (DNAPL) remediation. In addition to the increase of DNAPL solubility, co-solvents (e.g. ethanol) can alter the viscosity and density of aqueous phase and diffusion coefficient of solute. Any changes in these parameters can change the flow behaviour and alter the upscaled DNAPL mass transfer coefficient which is a key parameter controlling soil and groundwater remediation at Darcy-scale. While numerous studies have investigated DNAPL remediation using co-solvents at the Darcy scale, pore-scale modelling of co-solvent enhanced DNAPL remediation has not been well investigated. In this work, a three-dimensional pore-network model was developed to simulate the 1,2-dichlorobenzene (DCB) remediation experiments using ethanol-water flushing solution. The model simulates the effect of changes in solubility, viscosity, density, and diffusion coefficient during co-solvent flushing of the DNAPL. The results of pore network modelling for ethanol-water flushing for the DCB remediation were also validated using the experimental data. In addition to pore-scale modelling, a continuum scale modelling (Darcy-scale) was used for the DCB remediation using ethanol-water flushing. The results of both pore network and continuum scale modelling demonstrated that the ethanol content and flushing velocity influence the interphase mass transfer and DNAPL dissolution process. The results indicated while the mass transfer coefficient decreased in the presence of ethanol, the process of NAPL remediation was improved due to the substantial increase of solubility in the presence of co-solvent. The large scale modelling showed that NAPL bank can be formed in the front of ethanol-water mixture flushing.

Microscale investigation of DNAPL displacement by engineered graphene quantum dots in heterogeneous porous media

This x-ray microtomography study investigates the dynamic pore-scale displacement of a dense non-aqueous phase liquid (DNAPL) such as heavy crude oil in a heterogeneous aquifer rock using carbonaceous nanoparticles. The nanoparticles were synthesized from Wyoming coal and consisted of a mixture of graphene quantum dots (GQD) and engineered graphene quantum dots (E-GQD) in equal proportions. Synergistic interactions between GQD and E-GQD at the oil/water interface reduced the DNAPL/brine interfacial tension (IFT) from 13.4 mN/m to 5.4 mN/m. In addition, the nanofluid mixture altered the wettability of the minerals found in the rock (quartz, carbonate, and feldspar) from oil-wet to water-wet with average contact angles of 66°, 51°, and 60°, respectively. The wettability alteration was more pronounced in carbonates due to the tendency of GQD to adsorb on these surfaces. Analyses of the saturation profiles and pore-scale fluid occupancy maps revealed that the wettability alteration was not instantaneous and required a short soaking time for the fluid-rock interactions to take place. IFT reduction alone was not enough to displace the DNAPL at the early stages of nanofluid flooding because of the high density and viscosity of the oil. As a result, the nanofluid did not outperform brine after 1 pore volume (PV) of injection. On the other hand, the nanofluid was able to invade small pores that were not accessible to brine after 3 PV of injection due to both IFT and contact angle reduction, which lowered the threshold capillary pressure of these pores. Subsequently, more medium and large pores were invaded by the nanofluid as the injection continued, leading to an 11% increase in DNAPL recovery after 20 PV of nanofluid injection, as compared to waterflooding. This incremental recovery is significant considering that the experiments were performed with a heavy oil at ambient temperature, which is more representative of aquifer conditions. Thus, the GQD-based nanofluid has the potential to achieve much larger recoveries in deeper heavy oil reservoirs provided enough soaking time is allowed. The insights provided by this study could be used to validate pore-scale network models or guide in the design and selection of more effective nanomaterials for aquifer remediation or enhanced oil recovery applications.

A novel LBM-DEM based pore-scale thermal-hydro-mechanical model for the fracture propagation process

Fracture propagation in rocks is a complex thermal-hydro-mechanical (THM) phenomenon present in geotechnics, such as enhanced geothermal systems, CO2 sequestration, and shale gas exploitation. Numerical simulation is an essential way to study its mechanism. In this study, a pore-scale model combined with the lattice Boltzmann method (LBM) and the discrete element method (DEM) is developed, in which the comprehensive THM coupling phenomena are considered, consisting of convective heat transport, conjugate heat transfer, hydrodynamic force, and thermal strain. In addition, to couple the temperature and anisotropic thermal expansion of rock in LBM-DEM, a novel method based on the deformation of sphero-triangle particle is presented, where the deformation is calculated using the principle of minimum potential energy. The main features of the proposed THM model are that it can accurately calculate the fluid flow in fractures and the temperature in both fractures and DEM particles, and it takes full consideration of multiple anisotropic properties in rock. After validations, the THM fracturing mechanism is preliminarily investigated using the proposed model.

Fundamental Numerical Analysis of a Porous Micro-Combustor Filled with Alumina Spheres: Pore-Scale vs. Volume-Averaged Models

Inserting porous media into the micro-scale combustor space could enhance heat recirculation from the flame zone, and could thus extend the flammability limits and improve flame stability. In the context of porous micro-combustors, the pore size is comparable to the combustor characteristic length. It is insufficient to treat the porous medium as a continuum with the volume-averaged model (VAM). Therefore, a pore-scale model (PSM) is developed to consider the detailed structure of the porous media to better understand the coupling among the gas mixture, the porous media and the combustor wall. The results are systematically compared to investigate the difference in combustion characteristics and flame stability limits. A quantified study is undertaken to examine heat recirculation, including preheating and heat loss, in the porous micro-combustor using the VAM and PSM, which are beneficial for understanding the modeled differences in temperature distribution. The numerical results indicate that PSM predicts a scattered flame zone in the pore areas and gives a larger flame stability range, a lower flame temperature and peak solid matrix temperature, a higher peak wall temperature and a larger Rp-hl than a VAM counterpart. A parametric study is subsequently carried out to examine the effects of solid matrix thermal conductivity (ks) on the PSM and VAM, and then the results are analyzed briefly. It is found that for the specific configurations of porous micro-combustor considered in the present study, the PSM porous micro-combustor is more suitable for simplifying to a VAM with a larger Φ and a smaller ks, and the methods can be applied to other configurations of porous micro-combustors.

Pore-scale analysis on selection of composite phase change materials for photovoltaic thermal management

Composite Phase Change Materials (CPCMs) using metal foam as core material are highly promising for thermal management of photovoltaics. Selecting a proper CPCM for a given application is challenging. To address this, we developed a pore-scale lattice Boltzmann model based on X-ray micro-Computed Tomography to describe the complicated microstructures of the metal foam and computed the dynamic temperature and flow fields in representative applications. Two important parameters for the design of PCMs, melting temperature and latent heat, are discussed in this work by comparing the melting fraction, energy density, and power density for different CPCMs. Further, we demonstrate a CPCM choice for thermal management of a tilted photovoltaic panel. By comparing the thermal behavior of four different paraffin based CPCMs having similar thermophysical properties but different melting temperatures and latent heats, the effects of melting temperature and latent heat are illustrated for a practical application. Compared with the highest latent heat (Stefan number Ste = 0.1), energy density is reduced by 31.8%, 52.0%, and 63.5% for the other three cases with Ste of 0.15, 0.22, and 0.3, respectively, while the melting time is extended, with the reverse order. Besides, a lower melting temperature leads to a quicker response at the early melting stage, while this quick response is short-lived. Thus, the choice of melting temperature should balance the benefits of excellent initial thermal control against the risks of loss of control later. The results of this work help establish an effective strategy toward material selection of CPCMs.

Relationship between soil carbon sequestration and the ability of soil aggregates to transport dissolved oxygen

A key finding in soil carbon studies over the past decade is that soil organic carbon (SOC) stabilization is not controlled by its molecular complexity or adsorption to clay, but by its physicochemical protection including occlusion in aggregates and sorption-precipitation with organo-mineral associations. The organo-mineral complexes and the adsorbed SOC can be dissolved microbially under anoxic conditions, which is an important pathway in carbon cycle but has been overlooked by most carbon models. As organo-mineral associations are reported to form in aerobic conditions and can be lost under anaerobic conditions, there should be a positive correlation between SOC and ability of the aggregates to transport dissolved oxygen. We develop a simulation model to test this using soil structural data from two long-term experiments which naturally created a SOC gradient: One is a winter wheat experiment established in 1843 to compare the effects of different fertilizations on the yield of winter wheat and the other one is a ley-arable experiment established in 1948 to investigate the consequence of cropping system changes for ecological yield. Aggregates from different treatments on the two experiments were scanned using X-ray Computed Tomography to simulate oxygen transport using a pore-scale model. We compared porosity and diffusion coefficient of all aggregates and linked them to SOC measured from the two experiments. The agronomic practice changes which occurred 67 or 172 years ago substantially reshaped the intra-aggregate structure (<2 mm), and the accrual of SOC is positively correlated with diffusion coefficient of the aggregates to transport oxygen. However, the diffusion coefficient increases with SOC asymptotically, plateauing when SOC exceeds a threshold value. We also found the diffusion coefficient of the aggregates in chemically fertilized soils trended with their porosity approximately in the same way, deviating from those for other non-cropped treatments or fertilized with farmyard manure.

Intermittency effects in single- and multi-phase flow and anomalous transport in heterogeneous porous media

Multi-phase flow and transport in porous media is prevalent in a wide range of challenging fluid mechanics problems related to sustainability, energy, and the environment. Accurate prediction of the displacement and interaction of such flows is vital in addressing these problems. In particular it is critical to understand the small- or pore-scale flow and its spatial and temporal evolution, which can impact behaviors at system scales in a nontrivial manner. Intermittency is a phenomenon currently observed in numerical and experimental studies of single-phase flow (Anna et al., n.d.; Morales et al., n.d.), but the case of multi-phase flow has yet to receive much study due to challenges faced in both simulations and experiments. The underlying physics of spreading, mixing, and interfacial processes must be understood for accurate predictions of transport in multi-phase flow systems. Therefore, a comprehensive understanding of multi-phase flow at these very small scales is necessary in the development of accurate system-scale prediction models. We present results from a coordinated numerical and experimental study of intermittency effects over a range of viscous and inertial flow regimes in single- and multi-phase flows in 2D heterogeneous micromodels to quantify Lagrangian flow statistics to better inform pore-scale models. The applicability of different modeling frameworks such as the correlated-continuous time random walk is tested by studying statistics of particle trajectories obtained by particle tracking velocimetry (PTV) measurements and Lattice Boltzmann simulations from single- and multi-phase flows. The results make particular note of the influence of the pore Reynolds number (Re) and inertial effects on intermittency, and compare these effects in the two flow regimes.

3D pore-scale modeling of nanofluids-enhanced oil recovery

The numerical modeling of oil displacement by nanofluid based on three-dimensional micromodel of cores with different permeability was carried out by the volume of fluid (VOF) method with experimentally measured values of interfacial tension, contact angle and viscosity. Water-based suspensions of SiO 2 nanoparticles with a concentration of 0–1% and different particle sizes were considered to study the effect of concentration and size of nanoparticles, displacement fluid flow rate, oil viscosity and core permeability on the efficiency of oil displacement by nanofluid. The oil recovery factor (ORF) increases with the increase of mass fraction of nanoparticles. An increase in nanoparticles' concentration to 0.5% allows an increase in ORF by about 19% compared to water flooding. The ORF increases with the decrease of nanoparticle size, and declines with the increase of displacing rate. It has been shown that the use of nanosuspensions for enhanced oil recovery is most effective for low-permeable reservoirs with highly viscous oil in injection modes with capillary number close to the immobilization threshold, and the magnitude of oil recovery enhancement decreases with the increase of displacement speed. The higher the oil viscosity, the lower the reservoir rock permeability, the higher the ORF improved by nanofluids will be.

AN ANALYTICAL MODEL FOR PORE AND TORTUOSITY FRACTAL DIMENSIONS OF POROUS MEDIA

Accurate characterization of pore-scale structures of porous media is necessary for studying their transport mechanisms and properties. An analytical model for pore and capillary structures of porous media is developed based on fractal theory in this study. The pore and tortuosity fractal dimensions are introduced to characterize the pore size distribution and tortuous flow paths. A power law scaling between fractal probability function and pore diameter is proposed, which can be applied to determine the pore fractal dimension. The explicit expression for tortuosity fractal dimension is derived based on exactly self-similar fractal set and fractal capillary bundle model. The present fractal model has been validated by comparison with that of experiments and numerical simulations as well as theoretical models. The results show that the tortuosity fractal dimension decreases as porosity and pore fractal dimension increase, it increases with the increment of tortuosity. Both the particle shape and pore size range take important effect on the tortuosity fractal dimension under certain porosity. The proposed pore-scale model can present a conceptual tool to study the transport mechanisms of porous media and may provide useful guideline for oil and gas exploitation, hydraulic resource development, geotechnical engineering and chemical engineering.

Pore scale modeling on dissociation and transportation of methane hydrate in porous sediments

Fundamental study on the pore scale dissociation and transportation mechanism of methane hydrate in porous sediments contributes to understanding the heat and mass transfer in the multiple physicochemical and thermal processes. This paper proposes a novel enthalpy-porosity technique coupling with volume of fraction (VOF) method for modeling the phase-change process of the hydrate dissociation and the multi-phase flow. The mathematical models are programed by C language and used as the subroutine for the commercial FLUENT software. The proposed theoretical model is validated by comparison with the experiment and numerical modeling in literature. The distribution of fluid saturation, velocity and temperature in the MH dissociation are presented, analyzed and discussed comparatively. As the first effort in literature, the proposed model can properly simulate the effects of the phase change on the pore structure evolution, multiphase flow, heat and mass transfer and kinetic reaction process in porous media in real-time. Both the normalized permeability of water (KNw) and the normalized absolute permeability (KN) of the porous media with different hydrate saturation are acquired and analyzed comparatively with the results in the previous studies. This study provides a new insight into pore scale modeling on the multiphase flow with phase change.

Multi-scale modelling on PEM-based electrolyte dehumidifier: Transient heat and mass transfer in anode catalyst layer with microstructures

As an independent and ultra-compact method, PEM-based dehumidifiers are promising, while accurate modelling of anode-side transport is still challenging. The theoretical model developed in this study is transient, two-dimensional and non-isothermal based on the lattice Boltzmann method, emphasizing the anode-side catalyst layer (CL) with reconstructed microstructures. Then the pore-scale CL modelling was coupled with the macro-scale simulation of air channel and diffusion layer (DL), and experimentally validated by a 3.5 cm2 dehumidifier. Results showed that the CL microstructure significantly affects the air outlet parameters of PEM dehumidifiers, especially in the beginning state. Although the uniform distribution of vapor concentration can be achieved immediately in CL, the time required for the air outlet to reach transient equilibrium is much longer, which is around 1000s for the moisture content and 7000s for the temperature. The moisture transfer resistance at the beginning state mainly exists in CL, then it moves to both CL and DL (close to the interface) when it reaches equilibrium. Due to the continuous heat generation, the temperature flux in CL dominates in the anode side, and increases by 5-6 times during dehumidification. The calculated values of effective mass diffusivity and thermal conductivity of CL are 7.71×10−6 m2/s and 0.063 W/m•K. The randomly arranged catalyst particles makes CL the hottest (2~3°C higher) and driest (half the DL concentration) part of PEM element, which severely limits the whole performance. This modelling reveals the interaction between anode-side CL with microstructures and the performance, considering the transient heat and mass transfer.

Characterizing the Microstructure of Separators in Lithium Batteries and Their Effects on Dendritic Growth

Porous separators are used to physically separate the electrodes in batteries while providing mechanical stability and improving the performance of lithium batteries. In this study, the effect of the battery separator microstructure on mass transport and lithium dendrite growth is investigated using pore-scale computational modeling. The microstructural characteristics of the separator, such as porosity, tortuosity, and constrictivity, directly alter diffusion paths for lithium ions during battery cycling. The accuracies of experimental relations, i.e., Bruggeman, MacMullin, used to determine these characteristics are unreliable. A pore-scale computational model is used to simulate mass transport and dendrite growth, utilizing an explicit representation of the separator microstructure. The simulation is compared to the experimental relations and shows that the experimental relations fail to adequately capture important physical characteristics in the microstructure of the separator. Tortuosity, a characteristic that is difficult to experimentally measure, is shown to significantly affect the growth rate of dendrites and can lead to a shorter lifetime in the battery. Additionally, the degree of heterogeneity in a battery separator is explored and shown to lead to different dendrite growth rates even when the bulk physical characteristics of separators are the same. Evidence provided in this paper suggests that neglecting local variation of these properties can lead to nonuniform diffusion and, in turn, problematic dendritic growth. The findings offer insight into properties not often considered in battery separator designs.

Influence of grain size distribution on the physical characteristics of cementing hydrate-bearing sediment

Nature gas hydrates (NGHs) are considered as an ideal substitute for traditional fossil fuel. The evaluation of the physical properties of hydrate-bearing sediment (HBS) is important to develop reasonable exploitation strategies and clarify the corresponding main controlling factors. In this study, to determine the influence of grain size distribution on the physical properties of HBSs, 24 hydrate-bearing models were reconstructed based on a novel pore-scale 3D morphological modeling algorithm. A series of pore system evaluations and permeability simulations were carried out by pore network modeling (PNM). Moreover, thermal and electrical simulations were carried out using the finite volume method (FVM). The results are as follows: (1) The smaller the grain size is, the smaller the radius of the pores and throats of HBSs will be, which makes it easier for the connectivity between pores and throats to deteriorate as the hydrate saturation increases. (2) With increasing hydrate saturation, the permeability of HBSs gradually decreases. According to the decline rate, it can be divided into two stages: in the first stage, it will decrease sharply, while in the second stage, it will decrease slowly. In general, the smaller the grain size is, the lower the permeability of HBSs will be. (3) The apparent thermal conductivity of HBSs will increase as the hydrate saturation increases. The smaller the grain size is, the higher the apparent thermal conductivity will be. (4) The smaller the grain size is, the lower the apparent electrical conductivity and the higher the resistivity index under the same hydrate saturation will be.

Practical aspects of absolute permeability finding for the lattice Boltzmann method and pore network modeling

The importance of pore-scale models deals with their ability to estimate macroscopic parameters such as capillary pressure, absolute and relative permeabilities that are important input data of any reservoir model while studying the microscopic structure of the given samples.The current paper aims to discuss practical aspects of two widely applied techniques for absolute permeability estimation, lattice Boltzmann method (LBM) and pore network modeling. Both approaches analyzed three sandstone and one carbonate samples with different pore structures from the open database of Imperial College London. First, a direct pore-scale modeling via LBM approach was built based on the single relaxation time concept. Later on, pore networks were extracted by using the fast and efficient SNOW algorithm which could be considered as an improved version of a well-known watershed segmentation approach. The paper does not only compare the accuracy of two methods, but rather summarize in which cases a direct pore-scale modeling can be substituted by the simplified pore network approach. It also highlights importance of new insights, for instance, consideration of image resolution and representative elementary volume of the samples as a part of their analysis.Results demonstrate that direct pore-scale modeling allowed to reach a reasonable accuracy in absolute permeability estimation for three studied sandstone samples, although this method will not properly work for bigger pore volume while running simulations on CPU. At the same time, pore networks were able to find values of absolute permeability with reasonably low errors for all samples by varying the filtering parameters while preparing images.

Validation of a multicomponent reactive-transport model at pore scale based on the coupling of COMSOL and PhreeqC

Pore scale modelling in porous media is a field of research where interfaces such as the fluid – mineral boundary are explicitly represented and avoids volume-averaged properties such as porosity, permeability and reaction rates as required in a continuum scale approach. Setting up, running and extracting data from a pore scale model can be complex involving multiple software packages and coding for each problem. A new implementation of a multicomponent reactive-transport model at pore scale is presented using a java interface combining COMSOL and PhreeqC (iCP). The new model is tested using benchmark problems recently published and by simulating a laboratory experiment. The main advantages of this model are the implementation of the aqueous speciation, easy incorporation of different reaction mechanisms and rate laws, parallelization of geochemical calculations and a user-friendly interface. The iCP results agree with the benchmark and experimental results very well confirming its application to reactive-transport problems with dynamic pore geometry evolution. The importance of aqueous speciation and the chosen rate constants are demonstrated for calcite dissolution. Given the model transfers data between two codes and computes the aqueous speciation for every time step, the model is computationally expensive. Its advantages are the user-friendliness and its accuracy in computing local reaction rates and fluid composition.

Pore-Scale Modeling of Air–Water Two Phase Flow and Oxygen Transport in Gas Diffusion Layer of Proton Exchange Membrane Fuel Cell

Understanding multiphase flow and gas transport occurring in electrodes is crucial for improving the performance of proton exchange membrane fuel cells. In the present study, a pore-scale model using the lattice Boltzmann method (LBM) was proposed to study the coupled processes of air–water two-phase flow and oxygen reactive transport processes in porous structures of the gas diffusion layer (GDL) and in fractures of the microscopic porous layer (MPL). Three-dimensional pore-scale numerical results show that the liquid water generation rate is gradually reduced as the oxygen consumption reaction proceeds, and the liquid water saturation in the GDL increases, thus the constant velocity inlet or pressure inlet condition cannot be maintained while the results showed that at t = 1,200,000 iterations after 2900 h running time, the local saturation at the GDL/MPL was about 0.7, and the maximum value was about 0.83, while the total saturation was 0.35. The current density reduced from 2.39 to 0.46 A cm−2. Effects of fracture number were also investigated, and the results showed that for the fracture numbers of 8, 12, 16, and 24, the breakthrough point number was 4, 3, 3, and 2, respectively. As the fracture number increased, the number of the water breakthrough points at the GDL/GC interface decreased, the liquid water saturation inside the GDL increased, the GDL/MPL interface was more seriously covered, and the current density decreased. The pore-scale model for the coupled multiphase reactive transport processes is helpful for understanding the mechanisms inside the porous electrodes of PEMFC.

Pore-Scale Modeling of Fluid–Rock Chemical Interactions in Shale during Hydraulic Fracturing

Pore-Scale Modeling of Fluid–Rock Chemical Interactions in Shale during Hydraulic Fracturing

Pore-scale investigation on multiphase reactive transport for the conversion of levulinic acid to γ-valerolactone with Ru/C catalyst

Hydrogenation of levulinic acid (LA) into γ-valerolactone (GVL) with Ru/C catalytic system involves homogeneous/heterogeneous reactions, multiphase mass transfer and hydrogen dissolution. The understanding of these physiochemical phenomena is fundamental to propose the performance improvement strategies in such reaction system. In this study, a pore-scale multiphase reactive transport model based on the lattice Boltzmann method (LBM) is developed to simulate the conversion of LA to GVL over Ru/C catalyst. A Carnahan-Starling equation of state (CS EOS) modified Shan-Chen pseudopotential model is applied for gas–liquid flow. The model is validated by comparing the simulation predictions with existing experimental results. Simulation results show that the intra-particle diffusion distance of hydrogen is shorter than that of LA. The LA consumption rate is found to be determined by temperature and dissolved hydrogen when the average concentration of LA is higher than a critical value (about 0.5 mol/L). Notable negative effect of LA intra-particle mass transfer on the reaction has been observed for the LA average concentration lower than 0.5 mol/L. The reaction-generated water would result in a little inhibition on LA hydrogenation. To enhance the utilization of catalyst and reduce the local transport resistant, hollow spheres or coating catalyst are more effective for this system. We demonstrate the usefulness of the present pore-scale LB model in providing guidance for efficient hydrogenation LA into GVL.

Influence of Particle Size Distribution on the Physical Characteristics of Pore-Filling Hydrate-Bearing Sediment

Nature gas hydrates (NGHs) are regarded as a potential alternative energy source due to their huge reserves and wide distribution. According to the geophysical surveys, the pore-filling hydrates occupy a large proportion of the global hydrate reserves, especially for the marine regions. Therefore, with a novel pore-scale 3D morphological modeling algorithm, this study systematically studied the effect of the particle size on the physical characteristics of the pore-filling hydrate-bearing sediment (HBS). The pore system evaluations and permeability simulations were performed by utilizing pore network modeling (PNM), and the thermal and electrical simulations were conducted by utilizing a finite volume method (FVM). The results show that for the HBS with smaller particle size, the average radius of the pores and throats would also be reduced, and the fractal dimension of the pore system would be increased. In addition, with the increasing hydrate saturation, the fractal dimension of the pore system will increase firstly and then decrease. And these parameter evolutions could impact the physical properties correspondingly; specifically, the decreasing particle size in the HBS would reduce the permeability and electrical conductivity of HBS and enhance the apparent thermal conductivity of HBS.