non-Darcy Flow Research Articles

Effects of ground motion characteristics on liquefaction response of earth dams using a non-Darcy hydro-mechanical model

During earthquake-induced excitations, significant pore pressure gradients can develop in earth dams, limiting the applicability of Darcy’s law for fluid flow. This study investigates the behavior of a liquefied earth dam subjected to various seismic excitations with differing frequency content, aiming to enhance insights into the effects of dynamic loading on fluid–structure interactions. To accurately capture the soil’s response, the Pastor-Zienkiewicz generalized plasticity model is employed to represent realistic soil behavior. Additionally, a modified Forchheimer equation is used to address varying permeability through a non-Darcy flow law. Numerical simulations, performed using a finite element code developed in Fortran, are validated through comparative analyses with previous studies. The results show that in low-permeability regions, changes in earthquake frequency content have minimal impact on discrepancies between the predicted results of Darcy and non-Darcy models. However, the non-Darcy model generally estimates horizontal displacements to be around 4% higher on average in these regions. This difference increases as earthquake frequency content decreases, reaching up to 6%. In contrast, in permeable regions, the non-Darcy model predicts significantly higher horizontal displacements, with an average increase of approximately 20% for high-frequency seismic events and 8% for low-frequency ones. Additionally, in high-permeability regions, the non-Darcy model deviates notably from the Darcy model as peak ground velocity increases, particularly affecting the upstream shell and clay core of the dam. This disparity becomes more pronounced as the input motion’s frequency content decreases, resulting in elevated pore pressures and slightly reduced vertical displacements in these regions.

Analysis of thermophoresis and transpiration impacts on electromagnetic convective non-Darcy radiative flow past a rotating cone

This study presents a comprehensive mathematical model to investigate the intricate transport processes involving transpiration, thermal radiation, and a magnetic field in a viscous, incompressible fluid around a rotating vertical cone. By applying suitable transformations, the governing equations were non-dimensionalized and then solved numerically using the bvp4c method. The resulting velocity, temperature, and concentration profiles were examined under practical boundary conditions, and the findings were found to be in excellent agreement with the existing literature, validating the model's accuracy. The study further explores the influence of various factors, including the thermophoretic coefficient, magnetic field, thermal radiation, transpiration, Forchheimer parameters, and relative differences in temperature and concentration, on the flow characteristics. Additionally, the impact of these parameters on mass and heat transfer rates, represented by the Sherwood and Nusselt numbers with thermophoretic particle deposition velocity Vd* and local Stanton number Str was analyzed. Notably, the study highlights the sensitivity of the wall thermophoretic velocity to changes in physical parameters, which significantly affects the flow behavior under different transpiration parameter values. The findings of this study provide valuable insights into the complex interplay between the governing physical phenomena and offer a robust numerical framework for understanding and predicting the transport processes in rotating vertical cone systems with practical applications in various fields, such as engineering, geophysics, and astrophysics.

Comprehensive analysis of gas slippage and Non-Darcy flow in carbonate rock samples under stress conditions

This study examines the influence of stress on gas slippage and non-Darcy flow behavior in carbonate porous media, using core samples from two large carbonate reservoirs in the Middle East. Permeability measurements under varying stress conditions revealed significant increases in both the gas slippage factor and the non-Darcy coefficient with rising stress, indicating a related decrease in permeability. A new mathematical model, incorporating effective tortuosity and slippage radius into the Kozeny-Carman equation, was developed to accurately describe the stress-dependent nature of gas flow. Analysis of key pore attributes—such as porosity, pore size, shape, and tortuosity—underscored the critical role of pore structure, especially pore size and connectivity, in governing fluid flow under stress. These findings highlight the need to account for stress effects in reservoir engineering for improved modeling and management of carbonate reservoirs.

Multiphysics Field Coupled to a Numerical Simulation Study on Heavy Oil Reservoir Development via Electromagnetic Heating in a SAGD-like Process

Conventional thermal recovery methods for heavy oil suffer from significant issues such as high water consumption, excessive greenhouse gas emissions, and substantial heat losses. In contrast, electromagnetic heating, as a waterless method for heavy oil recovery, offers numerous advantages, including high thermal energy utilization, reduced carbon emissions, and volumetric heating of the reservoir, making it a focus of recent research in heavy oil thermal recovery technologies. This paper presents a numerical simulation study of electromagnetic heating for heavy oil recovery, using a heavy oil block in the Bohai Bay oilfield in China as a case study. Firstly, a multiphysics field coupled to a mathematical model was established, considering the impact of the temperature on the heavy oil viscosity, the threshold pressure gradient of non-Darcy flow, and the dielectric properties of the reservoir, along with heat dissipation from overlying and undercover sandstone and gravitational effects on fluid flow. Secondly, a numerical simulation method for the coupled multiphysics fields was developed, and the convergence and stability of the numerical simulation method were tested. Finally, a sensitivity analysis based on the numerical simulation results identified the factors affecting heavy oil production. It was found that electromagnetic heating significantly enhances heavy oil production, and the threshold pressure gradient greatly influences the prediction of heavy oil production. Moreover, heat dissipation from the overlying and undercover sandstone severely reduces cumulative oil production. When the production well is located below the electromagnetic heating antenna, larger well spacing results in higher cumulative heavy oil production. Higher heavy oil production is achieved when the antenna is positioned at the center of the reservoir for the studied cases. Power has a big effect on increasing heavy oil production, but its influence diminishes as power increases. There exists an optimal range of electromagnetic frequencies for maximum cumulative production, and higher water saturation leads to poorer electromagnetic heating efficiency. This study provides a theoretical foundation and technical support for the numerical simulation technology and development plan optimization of heavy oil reservoirs subjected to electromagnetic heating.

Compositional simulation of coupled transport mechanisms in fractured-vuggy underground gas storage: A case study of LWC in the Sichuan Basin

Compositional models were built to simulate the underground gas storage (UGS) operation, which is characterized by multiple cycles of rapid injection and production. Based on the validated model of the fractured-vuggy underground gas storage Lao Weng-Chang (LWC), this study evaluated the individual and coupling effects of stress sensitivity, relative permeability hysteresis, and high-speed non-Darcy flow on UGS operation. It was found that stress sensitivity is the main controlling factor behind the reduced working gas volume, and it led to a 6.07% decline in working gas volume. Relative permeability hysteresis is the determining factor for the storage capacity, and it led to a 9.05% decline in storage capacity. The high-speed non-Darcy flow only led to a 0.16% reduction in storage capacity but led to a 4.19% decline in working gas volume. A higher stress sensitivity coefficient and increased residual gas saturation both lead to greater losses in both storage capacity and working gas volume. Coupling stress sensitivity and relative permeability hysteresis would have a more pronounced effect on working gas volume than when considered individually. Considering the high-speed non-Darcy flow further decreases working gas volume. The gas production per unit pressure drop will also decrease with the increasing Reynolds number, and there exists a critical value of Re where the decrease significantly accelerates.

From Darcy to turbulent flow: Investigating flow characteristics and regime transitions in porous media

This research addresses the flow characteristics within a porous medium composed of a monolayer of closely packed spheres, spanning from viscous-dominated to turbulent flow regimes. In the first part of this paper, the turbulent flow characteristics at a 30 MPa pressure drop within the domain are presented. The results are averaged across different cross sections between the inlet and outlet. In the second part of the study, simulations are conducted with pressure drops, ranging from nearly 0 to 100 MPa. The analysis finds distinct flow patterns within the domain and provides estimations for the permeability and the inertial term coefficient. Moreover, the transition from Darcy to non-Darcy and turbulent flow is achieved through the use of different criteria. The specified geometry is suitable for validating and calibrating simplified discrete element method models coupled with computational fluid dynamics. The main goal of this research is to produce a reliable benchmark to figure out the challenge of limited experimental data concerning fluid flow characteristics in densely packed granules specially subjected to high pressure conditions. To do this, representative specimens are designed, accurate simulations are conducted, and precise assessments of the results are carried out.

Feasibility of carbon dioxide geological storage in abandoned coal mine: A fully coupled model with validated multi-physical interactions

It has gained wide attention that Carbon dioxide (CO2) is to be injected into abandoned coal mines for geological storage of CO2-enhanced coalbed methane recovery. Although abundantly evidences in literature indicate that the injection of CO2 will cause lots of interactions among the mechanical characteristics of coal and the properties of CO2 flow, further studies on these multi-physical interactions are still necessary. In this work, a series of laboratory experiments to elucidate the multi-physical interactions of CO2 adsorption, softening effect of coal and the non-Darcy gas flow were conducted. Based on the experimental results, theoretical and empirical models to describe these coal-CO2 interactions were meticulously proposed and validated, the results turned out to be satisfactory. Consequently, the compressive strength and elasticity modulus of coal decrease exponentially with the increased injection CO2 pressure. The gas flow in coal obeys the Izbash non-Darcy model, and coal permeability can be well modified by the volumetric stress. By taking these coal-CO2 interactions into account, this study established of a fully coupled model for coal deformation and CO2 conservation. The model was then implemented into the numerical simulations of CO2 storage in abandoned coal mine by using the finite element method. A series of scenario-based numerical simulations was conducted to investigate the feasibility and limitation of CO2 storage in abandoned coal mine. The conducted experiments, models and numerical simulation will offer implications on the multi-physical interactions between coal and gas especially in CO2 storage in abandoned coal mines.

Discussion on the production mechanism of deep coalbed methane in the eastern margin of the Ordos Basin

This study builds upon the research progress in the theories of CBM desorption, diffusion, and seepage flow to explore the production mechanisms of deep coalbed methane (CBM) in the Daing-Jixian block, aiming to achieve scientific and reasonable control of gas wells. Theoretical analysis suggests that CBM adsorption belongs to liquid–solid interfacial adsorption, encompassing four stages: liquid phase adsorption—liquid phase desorption—composite desorption—gas phase desorption. Most of the desorbed gas is driven by a pressure differential in a Darcy's flow process. By calculating the Knudsen number (Kn) under various temperature, pressure, and fracture diameter conditions, the flow state can be identified. Whole-diameter CT scanning reveals a multi-scale pore-fracture system ranging from millimeters to micrometers to nanometers. Calculations show that during the gas well drainage and depressurization process, fractures of millimeter scale and larger exhibit Darcy's flow, while micron-scale fractures maintain Darcy's flow status above a reservoir pressure of 5 MPa; other scales primarily exhibit non-Darcy flow without significant macroscopic movement. In summary, starting from the fundamental mechanisms of the original multiscale tri-level pore-permeability system of the coal reservoir, through the post-fracturing transformation forming three diversion zones of high, medium, and low conductive regions, and transitioning from primarily free gas to desorbed gas in three production stages, an ideal comprehensive production model schematic for the study area has been established, providing theoretical support for on-site production management.

Sediment size effects on non-Darcy flow: insights from Izbash equation and Forchheimer inertial coefficient analysis

The transition from Darcy to non-Darcy flow regimes was investigated using column experiments. This revealed key relationships between sediment characteristics and critical thresholds for the onset of the non-Darcy flow regime, as well as inertial flow parameters. An exponential dependence of the critical Reynolds number (Rec) on hydraulic conductivity (K) and a linear dependence on sediment size (d50) was found. The analysis revealed a potentially universal relationship between the critical hydraulic gradient (Ic) and K, with a power-law exponent of –3/2, consistent with previous investigations. Additionally, Ic was found to be inversely proportional to the power law of the square root of d50. Novel relationships are derived for estimating the Izbash equation inertial exponent (n) and the Forchheimer inertial coefficient (β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta$$\\end{document}) based on sediment characteristics. The exponent (n) was found to decrease with d50 and increase with K, following power-law relationships. A new equation is proposed, capable of predicting β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta$$\\end{document} with slightly improved accuracy, outperforming numerous and previously proposed empirical equations. Additionally, these data validate the works of Ergun and Irmay as an alternative for β\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta$$\\end{document} estimation using porosity and sediment size. As the attainment of statistical significance in multiparameter curve fitting can be trivial, it has led to the proliferation of empirical equations for estimating β. This study highlights the limitations of existing empirical methods in determining β and emphasizes the necessity for a universal approach to predict this critical parameter, which will facilitate broader adoption of the Forchheimer equation.

Novel coupled hydromechanical model considering multiple flow mechanisms for simulating underground hydrogen storage in depleted low-permeability gas reservoir

Depleted low-permeability gas reservoirs are the primary storage media for underground hydrogen storage (UHS). An accurate assessment of the geomechanics and complex flow mechanisms in a depleted low-permeability gas reservoir is crucial for predicting the injection and production capabilities of UHS facilities. This paper proposes a novel hydromechanical multicomponent model that couples non-Darcy flow, relative permeability hysteresis (RPH), and geomechanics to evaluate the hydrogen storage capacity of UHS facilities in a depleted low-permeability gas reservoir. The coupled model was solved using a fully coupled strategy, employing the finite volume method to solve non-Darcy flow equations and the virtual element method to solve geomechanical problems. The results indicate that the high-velocity non-Darcy (hvnD) and geomechanical effects reduce the working gas volume by 12.82% and 10.56%, respectively. Additionally, the low-velocity non-Darcy (lvnD) effect causes the third stress/strain distribution to exhibit a “focusing” phenomenon, resulting in a 13.19% reduction in the working gas volume. This paper also describes a case where residual gas is captured by mechanisms such as “water lock” and “capillary capture” through the RPH effect. Considering the RPH effect, the gas-water transition zone expanded by 30%, and the peak volume of gas-containing pores in the water zone increased by 1.48 times. Ignoring the RPH effect led to a 19.73% overestimation of the utilization rate of the gas-containing pore space. Hence, this study achieves safe and successful seasonal hydrogen storage and provides theoretical support for designing multicycle operational plans.

Numerical Simulation of Non-Darcy Flow in Naturally Fractured Tight Gas Reservoirs for Enhanced Gas Recovery

In this work, we analyze non-Darcy two-component single-phase isothermal flow in naturally fractured tight gas reservoirs. The model is applied in a scenario of enhanced gas recovery (EGR) with the possibility of carbon dioxide storage. The properties of the gases are obtained via the Peng–Robinson equation of state. The finite volume method is used to solve the governing partial differential equations. This process leads to two subsystems of algebraic equations, which, after linearization and use of an operator splitting method, are solved by the conjugate gradient (CG) and biconjugate gradient stabilized (BiCGSTAB) methods for determining the pressure and fraction molar, respectively. We include inertial effects using the Barree and Conway model and gas slippage via a more recent model than Klinkenberg’s, and we use a simplified model for the effects of effective stress. We also utilize a mesh refinement technique to represent the discrete fractures. Finally, several simulations show the influence of inertial, slippage and stress effects on production in fractured tight gas reservoirs.

Fractional Derivative Model on Physical Fractal Space: Improving Rock Permeability Analysis

As challenges in gas extraction from coal mines increase, precise measurement of permeability becomes crucial. This study proposes a novel pulse transient method based on a fractional derivative model derived on physical fractal space, incorporating operator algebra and the mechanics–electricity analogy to derive a new control equation that more accurately delineates the permeability evolution in coal. To validate the approach, permeability experiments were conducted on coal samples under mining stress conditions. The results showed that the adoption of a physically meaningful fractional-order relaxation equation provides a more accurate description of non-Darcy flow behaviour in rocks than traditional integer-order control equations. Additionally, the method proved effective across different rock types, verifying its broad applicability. By establishing a new theoretical foundation, this approach illustrates how the microscale fractal structure of rocks is fundamentally linked to their macroscale fractional responses, thereby enhancing the understanding of fractional modelling methods in rock mechanics and related domains.

A new fractal pore-throat chain model for non-Darcy flow through porous media

Non-Darcy flow through porous media is of great significance in hydraulics, oil and gas engineering, biomedical science, chemical and civil engineering etc. However, it is difficult to fully grasp the nature of fluid flow through porous media from macroscopic scale alone. Based on the statistically fractal scaling laws of pore structures, a new fractal pore-throat chain model (FPTCM) for non-Darcy flow through the isotropic porous media is developed. The analytical expressions for the Darcy and non-Darcy permeability as well as non-Darcy coefficient are derived accordingly. In order to explore the local flow field of high-speed non-Darcy flow through porous media, the finite element method is also carried out on an equivalent pore-throat unit. The predicted permeability by FPTCM shows better agreement with present numerical results and available experimental data, compared with commonly used semi-empirical formulas including Kozeny-Carman and Ergun equations. It has been found that both Darcy and non-Darcy permeability as well as non-Darcy coefficient strongly relate to the pore structures of porous media. The non-Darcy permeability is positively correlated to porosity, pore fractal dimension and Darcy permeability, while it is negatively related to tortuosity fractal dimension and pore size range. The non-Darcy coefficient shows opposite correlation with these parameters. The present work can provide theoretical basis for oil and gas development, nuclear waste treatment, carbon dioxide geological sequestration etc.

Coupling Upscaled Discrete Fracture Matrix and Apparent Permeability Modelling in DFNWORKS for Shale Reservoir Simulation

Modelling non-Darcy flow behaviour in shale rocks, composed of nanometer-sized pores and multi-scale fracture networks, is crucial for various subsurface energy applications. However, incorporating multiple physical mechanisms across numerous scales is not trivial. This work proposes an improved and practical upscaling workflow for coupling an Upscaled Discrete Fracture Matrix (UDFM) model and a pressure-dependent apparent permeability (Kapp) model to capture the effects of non-Darcy flow in multi-scale fractured shale reservoirs.First, a 3D DFN is upscaled into octree-refined continuum meshes, where equivalent rock parameters and rock-fluid functions are defined using the UDFM approach. Then, the flow simulation is coupled with a pressure-dependent Kapp updating scheme using an existing Kapp model and a multiple-restart technique. The effects of non-Darcy flow mechanisms (e.g., slip flow, transitional flow, Knudsen diffusion) are captured. The constructed models are then used to study the impacts of fracture network connectivity and pressure interference on production. The results of this new approach are compared against those obtained from another commercial package while preserving the advantages of DFNWORKS. Neglecting non-Darcy flow behaviours could significantly underestimate gas production and water recovery. It is illustrated that the nanoscale flow mechanisms help to enhance matrix-matrix and matrix-fracture flow. The constructed models are also utilized to study the effects of disconnected or isolated fractures, pressure interference, water retention, and shut-in durations on well performance. The proposed flexible strategies can be adopted in other commercial/open-source fractured-porous-media subsurface-flow simulation frameworks.

Predicting Water Inflow in Tunnel Construction: A Fracture Network Model with Non-Darcy Flow Considerations

Fractures are widely distributed in karst areas, and when flow rates are high, they exhibit complex nonlinear behavior that cannot be accurately described by Darcy’s law. In this work, a hydro-mechanical coupling model based on a discrete fracture network is proposed to predict tunnel water inflow, accounting for the impact of non-Darcy flow. The model’s feasibility has been validated by comparing it with experimental results and the field measurements of flow rates at the Bodaoling Tunnel in Guizhou, China. The results show that Darcy flow tends to overestimate water inflow by approximately 25% compared to non-Darcy flow. The non-Darcy effect grows with the increase in initial fracture width and empirical constant q. When q exceeds 8.77 × 10−6, the growth rate of the Forchheimer number along the fracture width slowed down, and the inhibitory effect of non-Darcy flow on flow became gentle. Additionally, in a complex fracture network, the inflow rate limited by non-Darcy flow at one point drives the water flow through a connect fracture to another point, which increases the difficulty in water inflow prediction. This work highlights the importance of non-Darcy flow and fracture networks when accurately predicting water inflow in tunnels.

Rate Transient Analysis for Multi-Fractured Wells in Tight Gas Reservoirs Considering Multiple Nonlinear Flow Mechanisms

Making rate transient analysis (RTA) and formation evaluation for multi-fractured tight gas wells has always been a difficult problem. This is because the fluid flow in the formation has multiple nonlinear flow mechanisms, including gas-water two-phase flow, gas slippage, low-velocity non-Darcy flow, and stress-dependent permeability. In this paper, a novel RTA method is proposed for multi-fractured wells in tight gas reservoirs incorporating nonlinear flow mechanisms. The RTA method is based on an analytical model, which is modified from the classical trilinear flow model by considering all the nonlinear flow mechanisms. The concept of material balance time and normalized rate is used to process the production data for both water and gas phases. The techniques of approximate solutions in linear/bilinear flow regimes and type curve fitting are combined in the proposed RTA method. After that, the rate transient behaviors and influencing factors of multi-fractured tight gas wells are analyzed. A field case from Northwestern China is used to test the efficiency and practicability of the proposed RTA method. The results show that six flow regimes for both gas and water production performances are exhibited on the log-log plots of normalized production rate against material balance time. The rate transient responses are sensitive to the nonlinear flow mechanisms, and formation and fracture properties. The medium flow regimes are significantly affected by fracture number, fracture conductivity, fracture half-length, stress-dependent permeability, gas-water two-phase flow, and formation permeability, which should be considered in making RTA of fractured tight gas wells. The field case shows that both gas and water production performances can be well-fitted using the proposed RTA method. The major innovation of this paper is that a novel RTA method is proposed for fractured tight gas wells considering multiple nonlinear flow mechanisms, and it can be used to make reasonable formation and fracturing evaluations in the field.

A dual-porosity flow-net model for simulating water-flooding in low-permeability fractured reservoirs

The physics-based data-driven flow-network models with high computational efficiency have received great attention as the promising surrogate models for reservoir numerical simulation. However, the existing flow-network models developed for water-flooding reservoirs fail to consider different seepage characteristics of matrix and fractures and cannot be straightly applied to simulate the water-flooding process in low-permeability fractured reservoirs. In this study, we combine the flow-network model with the dual-porosity model to propose a new physics-based data-driven surrogate model, namely the Dual-Porosity Flow-Network Model (Flow-Net-DP), which can consider the non-Darcy flow in tight matrix and the stress-sensitive effects and preferential flow characteristic in fractures. Specifically, we refer to the dual-porosity model and use two channels to represent the connections between wells: one indicates the fracture system, the other represents the matrix system, and the fluid exchange between these two systems is considered by using a transfer function. Besides, each channel is discretized into one-dimensional grids, and a fully implicit scheme with Newton iteration is used to calculate pressure and saturation. Moreover, we establish an automated history matching method by using the Ensemble Smoother with Multiple Data Assimilation (ESMDA) algorithm to calibrate model parameters of Flow-Net-DP, and develop a production optimization method by using the Differential Evolution (DE) algorithm. Finally, the numerical simulation, history matching, and production optimization are conducted on different numerical examples to validate the capability of Flow-Net-DP. The results indicate that the Flow-Net-DP can provide a better description of water flooding process in low-permeability fractured reservoirs compared with the existing flow-network model, especially the rapid water breakthrough caused by the preferential flow characteristic in fractures. Furthermore, both history matching and production optimization based on the Flow-Net-DP yield satisfactory outcomes. For instance, when the optimization results are similar to the full-order simulation model, the optimization speed of Flow-Net-DP is increased by more than five times.

Multi-parameter modeling for prediction of gas–water production in tight sandstone reservoirs

Tight sandstone reservoirs are significant sources of natural gas reserves. As traditional reserves become increasingly scarce and costly, optimizing the development of these reservoirs becomes crucial. This study introduces a novel two-phase gas–water flow model for single wells, incorporating both Darcy and non-Darcy flow equations. These equations are derived from mass conservation and momentum principles for both gas and water phases. Using data from a real tight gas well, our model, which includes stress-sensitive phases for gas and water, outperforms traditional Darcy flow models. Specifically, the average relative deviations in daily production rates were 0.1815% for gas and − 0.2677% for water, which are significantly smaller compared to traditional Darcy flow models. Further application of the non-Darcy flow model reveals strategies to enhance well performance. For example, mitigating liquid lock damage within a 2 m radius near the well could restore the permeability from 0.045 to 0.143 mD, thereby tripling the daily gas production. This non-Darcy flow model is easy to implement and shows significant potential in forecasting production yields in tight sandstone reservoirs, highlighting its importance in the petroleum and natural gas industry.

Darcy and Non-Darcy Flow Through Packing Particles

Darcy and non-Darcy flow through packing particles is an important study to determine the flow rate and pressure drop through porous media. Darcy is formed with a low liquid flow rate while the non-Darcy flow is formed with a high flow rate. The objective of this experiment is to determine the flow performance through packing particles. In this study, a syringe piston pump is used to inject the water through various packing particles. The permeability of the material was calculated using Darcy’s Equation. This study considered different variables such as: flow rate viscosity, the cross-sectional area of the sample, the pressure difference across the sample, and the length of the sample for the permeability calculation. The results showed high and low permeability rates of the specimens using in the experiment. Consequently, the results of this experiment can be used for selecting the best particle sizes for water treatments and hydraulic fracking in reservoir stimulation or enhanced oil recovery methods (EOR).

Analysis of time-dependent bearing capacity of pile foundation in marine soft soil region considering non-Darcy flow

Due to the deviation of pore water seepage in marine soft soils from Darcy flow under low hydraulic gradients, existing methods face challenges in accurately calculating the time-dependent bearing capacity of piles in such areas. This paper adopts the secondary development of Python to ABAQUS and employs a continuous coupling analysis method to establish a numerical model capable of simultaneously solving the large deformation of pile driving and non-Darcy flow. The model addresses issues such as mesh distortion during pile driving and the numerical implementation of three-dimensional non-Darcy flow. The accuracy of the model was verified through comparison with two experimental cases. Subsequently, the study analyzed how non-Darcy flow affects soil consolidation around the pile and the time-dependent bearing capacity of pile. Results indicate that when the permeability coefficient of the soil around the pile is less than 1 × 10−7 m/s, non-Darcy flow significantly delays the consolidation of soil within three times the pile diameter around the pile, thereby reducing the time-dependent bearing capacity of pile, with a greater impact observed for lower permeability coefficients of the soil. Once the soil around the pile reaches 90% consolidation, subsequent construction can proceed to shorten the project duration while maintaining safety.