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At least 415 records · Page 23
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Heterogeneity in Permeability and Particulate Organic Carbon Content Controls the Redox Condition of Riverbed Sediments at Different Timescales

Abstract The hydrological and biogeochemical properties of the hyporheic zone in stream and riverine ecosystems have been extensively studied over the past two decades. Although it is widely acknowledged that sediment heterogeneity can influence biogeochemical reactions, little effort has been made to understand the role of heterogeneity on the spatiotemporal variability of riverbed redox conditions under changing flow dynamics at different timescales. Here we integrate a mechanistic model and field data to demonstrate that heterogeneity in permeability plays a vital role in modulating sediment redox conditions at both seasonal (annual) and event (daily‐to‐weekly) timescales, whereas heterogeneity in particulate organic carbon (POC) content only has a comparable influence on redox conditions at the seasonal timescale. These findings underscore the importance of accurately characterizing sediment heterogeneity, in terms of permeability and POC content, in quantifying biogeochemical dynamics in the riverbed and hyporheic zones of riverine ecosystems.

Geology↗
DOE OSTI2020

Gas transport across the low-permeability containment zone of an underground nuclear explosion

Understanding the nature of gas transport from an underground nuclear explosion (UNE) is required for evaluating the ability to detect and interpret either on-site or atmospheric signatures of noble gas radionuclides resulting from the event. We performed a pressure and chemical tracer monitoring experiment at the site of an underground nuclear test that occurred in a tunnel in Nevada to evaluate the possible modes of gas transport to the surface. The site represents a very well-contained, low gaspermeability end member for past UNEs at the Nevada National Security Site. However, there is very strong evidence that gases detected at the surface during a period of low atmospheric pressure resulted from fractures of extremely small aperture that are essentially invisible. Our analyses also suggest that gases would have easily migrated to the top of the high-permeability collapse zone following the detonation minimizing the final distance required for migration along these narrow fractures to the surface. This indicates that on-site detection of gases emanating from such low-permeability sites is feasible while standoff detection of atmospheric plumes may also be possible at local distances for sufficiently high fracture densities. Finally, our results show that gas leakage into the atmosphere also occurred directly from the tunnel portal and should be monitored in future tunnel gas sampling experiments for the purpose of better understanding relative contributions to detection of radioxenon releases via both fracture network and tunnel transport.

98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL P↗
DOE OSTI2014

Three-dimensional magnetohydrodynamic Kelvin–Helmholtz instability of cylindrical flow with permeable boundaries

We study the linear magnetohydrodynamic Kelvin–Helmholtz instability of the interface between two viscous, incompressible, and electrically conducting fluids. The phases are enclosed between two coaxial cylindrical porous layers with the interface through which mass and heat transfer takes place. The fluids are subjected to a constant magnetic field parallel to the streaming direction, and the suction/injection velocities for the fluids at the permeable boundaries are also taken into account. Here, we use an irrotational theory in which the motion and pressure are irrotational, and the viscosity enters through the jump in the viscous normal stress in the normal stress balance at the interface. We consider both asymmetric and axisymmetric disturbances in our analysis. A quadratic dispersion relation is deduced and stability criterion is given in terms of a critical value of relative velocity, as well as, magnetic field. It has been observed that in the case of permeable boundaries, heat and mass transfer phenomena play a dual in the stability analysis. The flow through porous medium is more stable than the pure flow.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Irreversible thermodynamics of curved lipid membranes. II. Permeability and osmosis

We present a theory that combines the framework of irreversible thermodynamics with modified integral theorems to model arbitrarily curved and deforming membranes immersed in bulk fluid solutions. We study the coupling between the mechanics and permeability of a viscous and elastically bendable membrane, and a multicomponent bulk fluid solution. An equation for the internal entropy production for irreversibilities at the membrane is derived, determining the generalized thermodynamic forces and fluxes, from which we identify the deviatoric stress as a novel driving force for permeability. A complete set of equations of motion, constitutive laws, and boundary conditions to model the lipid membrane and bulk fluid system are provided.

Alkadri, Ahmad M↗
DOE OSTI2019

Reservoir Properties of Barremian – Aptian Urgonian Limestones, Se France, Part 1: Influence of Structural History on Porosity-Permeability Variations

Upper Barremian – Lower Aptian inner platform “Urgonian” limestones in the Mont de Vaucluse region, SE France, consist of alternating metre-scale microporous and tight intervals. This paper focuses on the influence of structural deformation on the reservoir properties of the Urgonian limestone succession in a study area near the town of Rustrel. Petrographic, petrophysical and structural data were recovered from five fully-cored boreholes, from the walls of a 100 m long underground tunnel, and from a 50 m long transect at a nearby outcrop. The data allowed reservoir property variations in the Urgonian limestones to be studied from core to reservoir scale. Eleven Reservoir Rock Types (RRTs) were identified based on petrographic features (texture, grain size), reservoir properties (porosity, permeability), and the frequency of structural discontinuities such as fractures, faults and stylolites. Tight and microporous reservoir rock types were distinguished. Tight reservoir rock types were characterised by early cementation of intergranular pore spaces and by the presence of frequent structural discontinuities. By contrast microporous reservoir rock types contained preserved intragranular microporosity and matrix permeability, but had very few structural discontinuities. Observed vertical alternations of microporous and tight rock types are interpreted to have been controlled by the early diagenesis of the Urgonian carbonates. Deformation associated with regional-scale tectonic phases, including Albian – Cenomanian “Durancian” uplift (~105 to 96 Ma) and Pyrenean compression (~55 to 25 Ma), resulted in the modification of the initial petrophysical properties of the Urgonian limestones. An early diagenetic imprint conditioned both the intensity of structural deformations and the associated circulations of diagenetic and meteoric fluids. Evolution of the Reservoir Rock Types is therefore linked both to the depositional conditions and to subsequent phases of structural deformation.

Cochard, J.↗
DOE OSTI2017

Dynamic magnetic permeability of the heterogeneous nanosystems based on (Co{sub 41}Fe{sub 39}B{sub 20}){sub x}(SiO{sub 2}){sub 100–} {sub x} composites

Thin films of (Co{sub 41}Fe{sub 39}B{sub 20}){sub x}(SiO{sub 2}){sub 100–} {sub x} nanocomposites and hybrid nanocomposite–semiconductor [(Co{sub 41}Fe{sub 39}B{sub 20}){sub x}(SiO{sub 2}){sub 100–} {sub x}/C]{sub 50} multilayers are synthesized by ion-beam deposition at various contents x of ferromagnetic metallic Co{sub 41}Fe{sub 39}B{sub 2O} nanogranules in an SiO{sub 2} matrix and at various carbon layer thicknesses h < 2 nm. Their magnetic and electrical properties, high-frequency magnetic permeability, magnetooptical spectra, and FMR spectra are studied. It is found that both the single-layer nanocomposites and the multilayers with carbon interlayers are superparamagnetic at x < x{sub per}, where x{sub per} is the electric conduction percolation threshold: a hysteresis at room temperature is absent, and the blocking temperature determined in quasi-static measurements does not exceed 20–30 K and weakly depends on the carbon layer thickness. At a carbon layer thickness h = 1.2–1.8 nm, the real and imaginary parts of complex magnetic permeability at 50 MHz and room temperature are substantially higher than those of the nanocomposites without carbon layers: their values are typical of ferromagnets. This dependence points to an exchange interaction between nanogranules in layers through a carbon interlayer. The influence of a conducting layer on the static and dynamic magnetic properties of a system of interacting superparamagnetic particles is discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Experimental study correlating damage and permeability in concrete using confined, flattened Brazilian disks

This research experimentally studies coupled hydro-mechanical relationships using flattened Brazilian disks under confinement, with concurrent permeability measurements and acoustic emission monitoring. A series of tests are performed on concrete, as representative samples of brittle geo-materials, under a range of confining stresses between 2.76 and 13.79 MPa. Acoustic emission data is used to quantify damage and identify damage thresholds. Damage is then correlated to pre-peak changes in permeability. The advancement of models that couple transport properties to mechanical responses are of interest in the fields of carbon sequestration, hydrofracking, production of geothermal energy, induced seismicity, and underground nuclear waste storage, and these experiments validate a novel experimental approach towards investigating hydro-mechanical relationships.

Boyce, S.↗
DOE OSTI2013

Moisture Durability of Vapor Permeable Insulating Sheathing [Fact Sheet]

In this project, Building America team Building Science Corporation researched some of the ramifications of using exterior, vapor permeable insulation on retrofit walls with vapor permeable cavity insulation. Retrofit strategies are a key factor in reducing exterior building stock consumption.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2014

Spectral SP: A New Approach to Mapping Reservoir Flow and Permeability

Our objectives for the current project were to develop an innovative inversion and analysis procedure for magnetotelluric field data and time variable self-potentials that will enable us to map not only the subsurface resistivity structure of a geothermal prospect but to also delineate the permeability distribution within the field. Hence, the ultimate objective were to provide better targeting information for exploratory and development drilling of a geothermal prospect. Field data were collected and analyzed from the Kilauea Summit, Kilauea East Rift Zone, and the Humuula Saddle between Mauna Loa and Mauna Kea volcanoes. All of these areas were known or suspected to have geothermal activity of varying intensities. Our results provided evidence for significant long-term coordinated changes in spontaneous potential that could be associated with subsurface flows, significant interferences were encountered that arose from surface environmental changes (rainfall, temperature) that rendered it nearly impossible to unequivocally distinguish between deep fluid flow changes and environmental effects. Further, the analysis of the inferred spontaneous potential changes in the context of depth of the signals, and hence, permeability horizons, were unable to be completed in the time available.

15 GEOTHERMAL ENERGY↗
DOE OSTI2018

Probability Distributions for Effective Permeability of Potentially Leaking Wells at CO 2 Sequestration Sites

Wells with defects originating from either poor completions or subsequent damage arising from chemical, thermal and/or mechanical stresses provide potential pathways for leakage of carbon dioxide (CO 2 ) and brine from a CO 2 sequestration site. This report provides a methodology for analyzing data on the frequency of occurrence of defective wells and the effective permeability of the damaged wells. The results include bimodal, log-normal distributions of the effective permeability of wells in addition to other distributions designed to provide a measure of the likelihood of encountering a leaking well in a CO 2 storage project.

58 GEOSCIENCES↗
DOE OSTI2019

Understanding the role of reactive chemistry and transport on the permeability of carbonate carbon storage reservoirs

Geologic carbon storage remains a critical technology to mitigate climate change as the world strives towards a carbon-free economy. Both sandstone and carbonate reservoirs are primary targets for geologic storage, with depleted oil and gas reservoirs viewed as first adopters of the technology, especially those reservoirs using CO 2 to enhance hydrocarbon recovery. Our work focuses on carbonate reservoirs because new pore space and enhanced permeability are likely to result as CO 2 and reservoir brines partially dissolve carbonate minerals until equilibrium is reached, particularly in fields subjected to CO 2 - enhanced oil recovery targeted for long-term CO 2 storage. Estimating meaningful changes in porosity and permeability in carbonate oil fields has been an active area of research. This topic is especially complicated because the significant pore and mineral heterogeneities characteristic of carbonate reservoirs play an outsized role in controlling reaction-induced fluid transport.

58 GEOSCIENCES↗
DOE OSTI2022

Fracture Adjacent Matrix Permeability: Insights from a Direct Experimental Approach

Description of a measurement technique, using a triple-pressure tap Hassler Style Core holder, that facilitates pressure measurement perpendicular to a fracture. Through the measurement of permeability changes at multiple distances from the fracture, this system enables an understanding of how end effects and localized ‘skin effects’ can impact the ability of fluids to move to and from the bulk matrix. Measurements of this type may lead to improved input values for reservoir simulations involving discrete fractures and/or dual-permeability.

47 OTHER INSTRUMENTATION↗
DOE OSTI2025

Modification of Fractured Rock Permeability Field Using Polymer Foam to Improve Geothermal System Efficiency

The project aims at developing novel methods for blocking high-permeability pathways in geothermal reservoirs to improve heat exchange efficiency. While the project was at DRI, and now when it has been transferred to UNR, the goal of blocking high-permeability pathways is achieved through targeted injection of heat-sensitive polymer foams, particularly foamed epoxy resins, whose activation and curing are triggered by the ambient thermal field.

15 GEOTHERMAL ENERGY↗
NASA NTRS1974

Membrane permeability and the loss of germination factor from Neurospora crassa at low water activities

Neurospora crassa conidia incubating in buffer at low water activities release a germination-essential component as well as 260-nm absorbing and ninhydrin-positive materials, regardless of whether an electrolyte or nonelectrolyte is used to reduce water activity. Chloroform and antibiotics known to increase cell-membrane permeability have a similar effect. This suggests that membrane damage occurs in media of low water activity and that an increase in permeability is responsible for the release of cellular components. The damage caused in media of low water activity is nonlethal in most cases, and the conidia recover when transferred to nutrient medium.

Charlang, G.↗
NASA NTRS1975

Urban land use: Remote sensing of ground-basin permeability

A remote sensing analysis of the amount and type of permeable and impermeable surfaces overlying an urban recharge basin is discussed. An effective methodology for accurately generating this data as input to a safe yield study is detailed and compared to more conventional alternative approaches. The amount of area inventoried, approximately 10 sq. miles, should provide a reliable base against which automatic pattern recognition algorithms, currently under investigation for this task, can be evaluated. If successful, such approaches can significantly reduce the time and effort involved in obtaining permeability data, an important aspect of urban hydrology dynamics.

Tinney, L. R.↗
NASA NTRS1976

Magnetic permeability measurements and a lunar core

Measurements of the magnetic field induced in the moon while it is in the geomagnetic tail lobes have been interpreted in terms of lunar magnetic permeability due to free iron content; such studies ignored the possibility that a highly conducting lunar core (Fe or FeS) would exclude magnetic fields with an apparent diamagnetic effect. Using lunar chemical and thermal models to determine plausible limits of magnetic permeability, we interpret measurements of the induced moment. The maximum likely radius of a lunar core is 580 km. Subsatellite and ALSEP measurements of the induced field are in disagreement. Resolving the differences is critical to determining whether a core could or does exist.

Goldstein, B. E.↗
NASA NTRS1977

Lunar magnetic permeability studies and magnetometer sensitivity

A regression of quiet magnetic field components simultaneously measured by the two Explorer 35 magnetometers reveals uncertainties in effective sensitivity factors of up to a few percent in one or both of these instruments. Given this, the validity of previous lunar permeability studies based on Explorer 35/ALSEP regressions, wherein inferences are drawn from regression line slopes differing from unity by the order of one percent, is called into question. We emphasize the need to critically address the question of small deviations in magnetometer sensitivity factors from nominal values as a part of any two-magnetometer lunar permeability study.

King, J. H.↗