SEARCH · Engineering Papers

Results for “permeability”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13

All sources NASA NTRS DOE OSTI

DOE OSTI2014

Leveraging a Fundamental Understanding of Fracture Flow, Dynamic Permeability Enhancement, and Induced Seismicity to Improve Geothermal Energy Production

This project focused on assessment and discovery of fluid-rock interaction in geothermal reservoirs. We accomplished work in four main areas: 1) fracture formation and the relationship between fluid flow and shear failure, 2) assessment of fracture geometry and fluid permeability using novel acoustic measurements, 3) an improved understanding of how drilling, injection and geothermal production influence local seismicity, and 4) development of process based models for using induced seismicity to assess the critical stress-state in Earth’s crust. The majority of the work involved laboratory experiments and analysis of laboratory and numerical results. We created shear fractures under true triaxial stresses designed to mimic the stress state of a geothermal reservoir and we measured fracture permeability as a function of stress state and fluid pressure under these conditions. Our work shows that fracture permeability can be altered by transient changes in stress and fluid flow. We find that fluid pressure has an unexpectedly larger impact on permeability than does applied stress and we interpret that result in terms of fracture contact area and the law of effective stress. We employ elastic waves to image fractures in the lab and develop the theory to apply our work to geothermal reservoir scale. Our work documents changes in elastic wave speed prior to earthquake-like failure in the lab and we show how the frequency magnitude distribution of microseismic lab earthquakes can be used to assess the critical stress state around faults prior to failure.

15 GEOTHERMAL ENERGY↗

DOE OSTI2021

Evolution of Pore Structure and Permeability of Rocks Under Hydrothermal Conditions (Final Report)

The physical and transport properties of porous rocks can be altered by a variety of diagenetic, metamorphic, and tectonic processes, and the changes that result are of critical importance to such industrial applications as resource recovery, carbon dioxide sequestration, and waste isolation in geologic formations. The associated interrelationships between rocks, pore fluids and deformation are also key to understanding many natural processes, including dynamic metamorphism, fault mechanics, fault stability and pressure solution creep. In this project, we investigated the changes of permeability and pore geometry owing to inelastic deformation by solution-transfer, brittle fracturing and dislocation creep. In particular, we studied the coupling between pore fluids and deformation in fluid-filled quartz, calcite, mudstones and ultramafic rocks and examine the effects of coupled mechanical and chemical processes on the evolution of porosity and permeability under hydrothermal conditions. The investigations used a combination of techniques, that included triaxial laboratory experiments; uniaxial compressive loading with in situ observations of microstructure; permeability under hydrostatic compression; observations of microstructure using optical and electron microscopes, and micro-CT imaging; and numerical calculations. Laboratory experiments were designed to provide mechanical and transport data under conditions that isolate the particular mechanisms responsible for the changes. The data obtained were used to quantify changes in surface roughness, porosity, pore dimensions and their spatial fluctuations. The results of the experiments and data from image analyses were compared to the results of network, finite-difference and other numerical models to verify the validity of experimentally established relations between permeability and other rock properties. A bibliography for the period from 2015-2019 is appended below. New results obtained in the final year and the unfunded extension period are detailed below.

58 GEOSCIENCES↗

DOE OSTI2025

Permeability Prediction Using Vision Transformers

Accurate permeability predictions remain pivotal for understanding fluid flow in porous media, influencing crucial operations across petroleum engineering, hydrogeology, and related fields. Traditional approaches, while robust, often grapple with the inherent heterogeneity of reservoir rocks. With the advent of deep learning, convolutional neural networks (CNNs) have emerged as potent tools in image-based permeability estimation, capitalizing on micro-CT scans and digital rock imagery. This paper introduces a novel paradigm, employing vision transformers (ViTs)—a recent advancement in computer vision—for this crucial task. ViTs, which segment images into fixed-sized patches and process them through transformer architectures, present a promising alternative to CNNs. We present a methodology for implementing ViTs for permeability prediction, its results on diverse rock samples, and a comparison against conventional CNNs. The prediction results suggest that, with adequate training data, ViTs can match or surpass the predictive accuracy of CNNs, especially in rocks exhibiting significant heterogeneity. This study underscores the potential of ViTs as an innovative tool in permeability prediction, paving the way for further research and integration into mainstream reservoir characterization workflows.

58 GEOSCIENCES↗

DOE OSTI2023

Advances in Computational Approaches for Estimating Passive Permeability in Drug Discovery

Passive permeation of cellular membranes is a key feature of many therapeutics. The relevance of passive permeability spans all biological systems as they all employ biomembranes for compartmentalization. A variety of computational techniques are currently utilized and under active development to facilitate the characterization of passive permeability. These methods include lipophilicity relations, molecular dynamics simulations, and machine learning, which vary in accuracy, complexity, and computational cost. This review briefly introduces the underlying theories, such as the prominent inhomogeneous solubility diffusion model, and covers a number of recent applications. Various machine-learning applications, which have demonstrated good potential for high-volume, data-driven permeability predictions, are also discussed. Due to the confluence of novel computational methods and next-generation exascale computers, we anticipate an exciting future for computationally driven permeability predictions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2017

Influence of Calcium Concentration on Permeability Changes in Flow-paths Altered by Highly Alkaline Groundwater - 17129

Groundwater around the geological repository of HLW is altered to the highly alkaline and Ca-rich condition by the constituents leaching from cementitious materials. Under such condition, the formation of CSH will affect the migration of radionuclides with the change in the hydraulic and chemical properties of the fracture (micro flow-path) in the host rock. In particular, the clogging effect with the deposition of CSH in the flow path the may contribute the retardation of radionuclide migration. In this study, the influence of Ca concentration on such clogging effect in the micro flow-path under the highly alkaline condition was examined by estimating the permeability changes with the deposition of CSH. In the experiment, the micro fractures in host rock were simulated by the micro flow-cell nipping the Teflon sheet (80 μm of thickness) between a granite chip and Teflon basement. The flow experiment was conducted by continuously injecting Ca solution to the micro flow-cell with constant flow rate. The concentrations of Ca ions for the injection solution were set in the range from 0 to 7.5 mM, and the value of pH was 12.5. As a result, under all conditions of Ca concentrations, the permeability in the flow path decreased to the range of 1. 10{sup -10} to 2.0x10{sup -10} m{sup 2} with the deposition of CSH. Besides, such decreased permeability was almost constant with increasing and decreasing periodically. Such increase and decrease in the permeability will be caused by the deposition and outflow of CSH formed in the flow path. In other words, because CSH is stable in pH higher than at least 10, under the condition with no man-made outlet such as real underground around the repository of radioactive waste, most CSH might clog through the flow-paths in the spatial range where pH exceeds at least 10, contributing the retardation effect of the migration of radionuclides released from the repository. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

Flow Rate Dependency of Permeability Changes with the Deposition of CSH under the Highly Alkaline Ca-rich Condition - 17175

The formation of calcium silicate hydrate (CSH) around the geological repository is one of the notable factors for the assessment of the radionuclide migration. This study discussed the clogging effect of CSH in flow path with the change in the flow rate based on the flow experiments using micro flow cell. In the experiment, the change of the permeability with the alteration of granite under the highly alkaline and Ca-rich condition was examined. As a result, the permeability in flow path gradually decreased with the periodical increase and decrease of the permeability. In addition, under the condition of the lower flow rate (0.06 ml/h), the permeability became much smaller than those for other conditions of the higher flow rates. These suggest that the clogging of flow path will progress with the local deposition/moving of CSH, in particular, under the condition of the lower flow rate. Retardation effect of radionuclide migration will be expected because it is prospected that flow rate of groundwater is lower than that of this study in the actual condition of repository. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

DOE OSTI2017

Pressure Loading with In-Situ Permeability Measurement of SiC Ceramic Matrix Composite Tube

Silicon carbide fiber in a silicon carbide matrix composite (SiC-SiC) has been actively researched as a potential structural material to be used in advanced high temperature gas reactors (HTGR) and as an accident tolerant cladding material for light water reactors (LWR). This ceramic composite material demonstrates desirable properties for use in nuclear reactor core that include retention of strength from ambient to LWR and HTGR operating and accident temperatures and stability under neutron radiation. However, the ceramic composite material must be designed to meet all the necessary, application driven requirements before it could be implemented in a reactor design. As one of the requirements for a fuel cladding material, the composite has to maintain high level of impermeability as to retain fission gases throughout the fuel cycle. General Atomics (GA) had previously reported results on permeability levels obtained by CVI produced SiC-SiC composites. It has been determined that for LWR size cladding tube that is 51 mm long the permeability allocation equivalent to currently used claddings is 7.3 E-10 atm*cc/sec. With high level of attention to possible sources of leaks in a test setup, it has been demonstrated that a CVI SiC-SiC composites produced by GA can achieve a leak rate of 1 E-12 atm*cc/sec, and therefore it meets the permeability allocation for a fuel cladding. Further study showed that a particular SiC-SiC composite tube can remain impermeable after being pressure loaded well above LWR normal operating conditions. In the study done by Deck et al., hoop stress was applied to a composite tube using pressure load on the inside surface in a load-unload stepwise sequence with increasing maximum applied stress at each step and measuring permeability between steps. The tested composite comprised of 70% thickness of SiC-SiC composite which provides fracture toughness and bears a majority of the applied stress and a 30% thickness of monolithic SiC layer on the outside surface to provide an impermeable barrier. The composite remained impermeable up to internal pressure of 56 MPa which is more than 2.5 times greater than a typical pressure at the end of life in a fuel rod.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2022

Gas Permeability Test Protocol for Ion-Exchange Membranes

The membrane-based electrolysis of water is a growing topic of interest due to the advantages of employing membranes in hydrogen production efficiency and system safety over the traditional alkaline water electrolysis. Ion-exchange membranes with low gas permeability are highly desirable for stable and safe operation of membrane-based water-splitting technologies, hence gas permeability through ion-exchange membranes needs to be properly assessed with standardized methods. We addressed three methods to measure gas permeability of ion-exchange membranes, a pressure permeation cell, chronoamperometry microelectrodes, and in situ testing of the membrane electrode assembly, and provide a guideline for choosing the appropriate method for the targeted operating conditions of the water electrolyzers.

08 HYDROGEN↗

DOE OSTI2017

The Effects of Strain-Annealing on Tuning Permeability and Lowering Losses in Fe-Ni-Based Metal Amorphous Nanocomposites

Here, Fe-Ni-based metal amorphous nanocomposites with a range of compositions (Fe 100–x Ni x ) 80 Nb 4 Si 2 B 14 (30 ≤ x ≤ 70) are investigated for motor and transformer applications, where it is beneficial to have tunable permeability. It is shown that strain annealing offers an effective method for tuning permeability in these alloys. For an Fe-rich alloy, permeability increased from 4000 to 16,000 with a positive magnetostriction. In a Ni-rich alloy, permeability decreased from 290 to 40 with a negative magnetostriction. Significant elongations (above 60%) are observed during strain annealing at high stress. Crystallization products have been determined in all alloys heated to 480°C. γ-FeNi is formed in all alloys, while (Fe 30 Ni 70 ) 80 Nb 4 Si 2 B 14 also undergoes secondary crystallization at temperatures of approximately 480°C to form a phase with the Cr 23 C 6 -type structure and a likely composition of Fe 21 Nb 2 B 6 . Toroidal losses have been measured for (Fe 70 Ni 30 ) 80 Nb 4 Si y B 16–y (0 ≤ y ≤ 3) at various annealing temperatures. At an induction of 1 T and frequency of 400 Hz and 1 kHz, the toroidal losses obtained are W 1.0T, 400 Hz = 0.9 W/kg and W 1.0T, 1 kHz = 2.3 W/kg, respectively. These losses are lower than losses recently reported for state of the art 3.0% and 6.5% silicon steels, a Metglas Fe-based amorphous alloy, and some Fe-based nanocomposites.

36 MATERIALS SCIENCE↗

DOE OSTI2018

Ascorbic acid attenuates endothelial permeability triggered by cell-free hemoglobin

Highlights: • Cell-free hemoglobin (CFH) increases endothelial barrier permeability. • Endothelial ascorbate is depleted following exposure to CFH. • Treatment of endothelial cells with ascorbate attenuates CFH mediated permeability. Increased endothelial permeability is central to shock and organ dysfunction in sepsis but therapeutics targeted to known mediators of increased endothelial permeability have been unsuccessful in patient studies. We previously reported that cell-free hemoglobin (CFH) is elevated in the majority of patients with sepsis and is associated with organ dysfunction, poor clinical outcomes and elevated markers of oxidant injury. Others have shown that Vitamin C (ascorbate) may have endothelial protective effects in sepsis. In this study, we tested the hypothesis that high levels of CFH, as seen in the circulation of patients with sepsis, disrupt endothelial barrier integrity.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

Chlamydia pneumoniae infection promotes monocyte transendothelial migration by increasing vascular endothelial cell permeability via the tyrosine phosphorylation of VE-cadherin

Highlights: • C. pneumoniae infection promotes monocyte TEM through increasing VEC permeability. • C. pneumoniae infection stimulates VE-cadherin tyrosine phosphorylation by Src. • VE-cadherin phosphorylation is involved in VE-cadherin internalization. • VE-cadherin phosphorylation is involved in EC hyperpermeability caused by infection. • VE-cadherin phosphorylation is associated with the infection-induced monocyte TEM. Migration of monocytes into the subendothelial layer of the intima is one of the critical events in early atherosclerosis. Chlamydia pneumoniae (C. pneumoniae) infection has been shown to promote monocyte transendothelial migration (TEM). However, the exact mechanisms have not yet been fully clarified. In this study, we tested the hypothesis that C. pneumoniae infection increases vascular endothelial cell (VEC) permeability and subsequent monocyte TEM through stimulating the tyrosine phosphorylation of vascular endothelial-cadherin (VE-cadherin). Here, we demonstrated that C. pneumoniae infection promoted monocyte TEM in a TEM assay possibly by increasing the permeability of a VEC line EA.hy926 cell as assessed by measuring the passage of FITC-BSA across a VEC monolayer. Subsequently, Western blot analysis showed that C. pneumoniae infection induced VE-cadherin internalization. Our further data revealed that Src-mediated VE-cadherin phosphorylation at Tyr658 was involved in C. pneumoniae infection-induced internalization of VE-cadherin, VEC hyperpermeability and monocyte TEM. Taken together, our data indicate that C. pneumoniae infection promotes monocyte TEM by increasing VEC permeability via the tyrosine phosphorylation and internalization of VE-cadherin in VECs.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2018

Hypoxic glioblastoma release exosomal VEGF-A induce the permeability of blood-brain barrier

Exosomes are nano-vesicles released by tumor cells to modulate extracellular environment. Accumulating evidence revealed that glioblastoma derived exosomes contain multiple pro-angiogenic factors to induce the proliferation of endothelial cells. Here, we investigated the role of GBM-derived exosomes in inducing the permeability of the blood-brain barrier. We found that VEGF-A was over-expressed in hypoxic GBM-derived exosomes, which enhance the permeability of a BBB in vitro model by interrupting the expression of claudin-5 and occludin. In vivo permeability assay showed hypoxic GBM-derived exosomes remained functional in the blood circulation and induced the permeability of BBB.

60 APPLIED LIFE SCIENCES↗

DOE OSTI2017

Fabrication and operational considerations of hydrogen permeable Mo 2 C/V metal membranes and improvement with application of Pd

Mo 2 C has previously been demonstrated as an effective catalyst layer to enable stable H 2 permeation through vanadium foils at high temperatures. Here, in this paper, this approach was extended to several group V metal foils (V, Nb, and Ta) as well as mixed gas testing. The best permeability was achieved with V, and an activation process was developed to recover the performance of V foils displaying evidence of oxidation. Nb foils yielded ~20% the permeability of V, while Ta was too brittle to operate effectively. Mo 2 C/V membranes were operated at feed conditions well above the ductile-to-brittle transition pressure without embrittlement; however, the H 2 permeability of Mo 2 C/V membranes was significantly attenuated at lower temperatures (< 600 °C). H 2 permeation was also severely inhibited by the presence of N 2 or CO 2 in mixed gas environments due to strong competitive adsorption. The addition of a Pd catalyst layer on top of Mo 2 C improved mixed gas stability and increased H 2 permeability to 2 × 10 -8 mol·m -1 ·s -1 ·Pa -0.5 at 500 °C for V based membranes. Lastly, as an interlayer, Mo 2 C was demonstrated to be a stable barrier preventing Pd-V interdiffusion at 500 °C while simultaneously allowing significant H 2 permeation.

08 HYDROGEN↗

DOE OSTI2020

Addressing wellbore integrity and thief zone permeability using microbially-induced calcium carbonate precipitation (MICP): A field demonstration

Microbially-induced calcium carbonate precipitation (MICP) is an emerging biotechnology for wellbore integrity applications including sealing defects in wellbore cement and modifying the permeability of rock formations. The goal of this field demonstration was to characterize a failed waterflood injection well and provide proof of principle that MICP can reduce permeability in the presence of oil using conventional oilfield fluid delivery methods. Here we compared well logs performed at the time the well was drilled with ultrasonic logs, sonic cement evaluation, and temperature logs conducted after the well failed. Analysis of these logs suggested that, rather than entering the target waterflood formation, injectate was traveling through defects in the well cement to a higher permeability sandstone layer above the target formation. Sporosarcina pasteurii cultures and urea-calcium media were delivered 2290 ft (698 m) below ground surface using a 3.75 gal (14.2 L) slickline dump bailer to promote mineralization in the undesired flow paths. By Day 6 and after 25 inoculum and 49 calcium media injections, the injectivity [gpm/psi] had decreased by approximately 70%. This demonstration shows that 1) common well logs can be used to identify scenarios where MICP can be employed to reduce system permeability, remediate leakage pathways, and improve waterflood efficiency, and 2) MICP can occur in the presence of hydrocarbons.

42 ENGINEERING↗

DOE OSTI2026

Oil in Alaska North Slope Gas Hydrate Reservoir: Micro-CT and Flow Simulation Insights into Permeability

Gas hydrate-bearing sands on the Alaska North Slope (ANS) host minor volumes of crude oil whose impact on formation permeability has never been quantified relative to a gas hydrate reservoir system. Here, we combine in situ pressure-core microcomputed-tomography (μ-CT), thermogravimetric analysis (TGA), gas-chromatography–mass-spectrometry (GC–MS), scanning-electron microscopy coupled with energy-dispersive spectroscopy (SEM-EDS), and Stokes-flow simulation to (i) quantify oil saturation, (ii) infer its source, and (iii) evaluate its influence on permeability after gas-hydrate dissociation. μ-CT and SEM-EDS imaging identify the host sediment as silty, with some grain-coating clay present. Eight representative 3003-voxel subvolumes extracted from a preserved pressure core (Core 15P-3c, from the B1 sand (unit B), HYDRATE 02 Geo Data Well (GDW), 886.96–887.29 m measured depth, MD) exhibit porosities of 0.34–0.37 and an average oil saturation of 0.09 ± 0.03, in comparison to an independent TGA-based estimate of 0.16. GC-MS fingerprints obtained from an adjacent depressurized core (Core 17P-1, 891.37–891.44 m MD), together with oil pore habit revealed by μ-CT, suggest that the oil is partly native but also includes contributions from mineral oil-based drilling fluid contamination. Further analysis of oil–porewater interactions and flushing tests confirms that native oil saturation in the analyzed samples ranges from 0.04 to 0.08 with an average of approximately 0.06, and the oil is highly immobile. Flow simulations demonstrate that the native oil saturation of ≈0.06 reduces permeability by approximately 50% due to both pore blockage and increased flow-path tortuosity. These findings reveal the potential presence of native oil within the ANS gas hydrate reservoir and suggest that future simulation models may need to account for its impact on permeability to improve long-term performance predictions of gas and water production.

02 PETROLEUM↗

DOE OSTI2019

Ensemble Shear Strength, Stability, and Permeability of Mixed Mineralogy Fault Gouge Recovered From 3D Granular Models

We conduct numerical shear experiments on mixtures of quartz and talc gouge using a three-dimensional (3D) distinct element model. A modified slip-weakening constitutive law is applied at contacts. We perform velocity-stepping experiments on both uniform and layered mixtures of quartz and talc analogs. We separately vary the proportion of talc in the uniform mixtures and talc layer thickness in the layered mixtures. Shear displacements are cycled through velocities of 1 and 10 μm/s. We follow the resulting evolution of ensemble shear strength, slip stability, and permeability of the gouge mixture and explore the mesoscopic mechanisms. Simulation results show that talc has a strong weakening effect on shear strength—a thin shear-parallel layer of talc (three particles wide) can induce significant weakening. However, the model offsets laboratory-derived strong weakening effects of talc observed in uniform mixtures, implying the governing mechanisms may be the shear localization effect of talc, which is enhanced by its natural platy shape or preimposed layered structure. Ensemble stability (a – b ) can be enhanced by increasing talc content in uniform talc-quartz mixtures. Reactivation-induced permeability increase is amplified with increased quartz content before the maturation of shear localization. Postmaturation permeability enhances on velocity upsteps and diminishes on velocity downsteps. Talc enhances compaction at velocity downsteps, potentially reducing fault permeability. Evolution trends of stability relating to the composition and structure of the fault gouge are straightforwardly obtained from the 3D simulation. Local friction evolution indicates that talc preferentially organizes and localizes in the shear zone, dominating the shear strength and frictional stability of faults

58 GEOSCIENCES↗

DOE OSTI2018

Analytical Model to Detect Fault Permeability Alteration Induced by Fault Reactivation in Compartmentalized Reservoirs

Underground fluid injection induces changes in in situ stress condition of the target formation and local faults that can potentially lead to fault reactivation, which may result in the leakage of injected and/or native fluids into neighboring formations. In this paper, we introduce an analytical method to detect fault reactivation caused by fluid injection into deep faulted aquifers considering across-fault leakage. The fundamental assumption made in our model is that fault permeability will be altered upon fault slip. Therefore, we model fault reactivation as a sudden change in fault permeability at the onset of fault slip. The fault is modeled as a linear interface between two permeable formations with equal rock and fluid properties. The governing equations are coupled through the fault interface and are solved using the Laplace-Fourier integral transform technique. Based on the analytical solution, we find the characteristic bottomhole pressure and pressure derivative responses that enable detecting fault reactivation using diagnostic plots. We observe that pressure derivative undergoes a rapid change at the onset of fault slip followed by a late-time trend to attain a new equilibrium governed by the altered fault permeability. Furthermore, we discuss the evolution of the across-fault leakage rate upon and after fault slippage. Here, the results from this study are presented in the form diagnostic plots and type curves that may be used for reservoir and fault characterization purposes.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2019

Relative Permeability Scaling From Pore-Scale Flow Regimes

Relative permeability measurements are commonly fitted with the Corey and Brooks-Corey correlations. Despite such correlations fit experimental data generally well, they are mostly of an empirical nature. Here, we propose a semiempirical model to determine relative permeabilities of the wetting and the nonwetting phases in real 3-D porous media that accounts for pore-scale flow regimes. The starting point is the homogenization framework proposed by Picchi and Battiato (2018, https://doi.org/10.1029/2018WR023172), where the upscaling is conducted for different spatial distributions of the flowing phases in the capillary tube setting. First, we extend the approach to realistic media by allowing pore-scale flow regimes to coexist in a complex geometry while accounting for capillary and viscous limits in the dynamics. Then, we discuss the scaling behavior of normalized relative permeabilities in terms of the phases viscosity ratio and identify three classes which govern their scaling. We also derive an analytical expression for the fractional flow. Finally, we provide a detailed validation of the proposed model for both relative permeabilities and fractional flow against data from numerical simulations and experiments available in the literature. Lastly, the data set used for validation covers a wide range of systems, ranging from brine-CO 2 to oil-water flows. The equations derived capture well the trend of both numerical and experimental data.

54 ENVIRONMENTAL SCIENCES↗