A two-region transport model for interpreting <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si20.svg"><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mn>1</mml:mn></mml:msub></mml:mrow></mml:math>-<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si21.svg"><mml:mrow><mml:msub><mml:mi>T</mml:mi><mml:mn>2</mml:mn></mml:msub></mml:mrow></mml:math> measurements in complex systems

Maneval, James E.; Nelson, Madison L.; Thrane, Linn W.; Codd, Sarah L.; Seymour, Joseph D.

doi:10.1016/j.jmr.2019.106592

Cited by 4 publications

(1 citation statement)

References 30 publications

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“…The aim of this work is to recommend not using this relationship, which lack is demonstrated showing the contradiction with the much more widely accepted relationships as well as a computation example from three typical decay rates. The discussed issues about permeability focus on applications of one-dimensional time NMR measurements, not considering the increasing applications of twodimensional NMR developments T 1 -T 2 , T 1 -D-T 2 , etc., mainly target on very small pore sizes (Bernin and Topgaard, 2013;Fleury and Romero-Sarmiento, 2016;Faux and McDonald, 2018;Maneval et al, 2019;Li et al, 2020). Hereafter, the influence of temperature on the relationship in question, and some especial conditions as the presence of paramagnetic particles in the pore fluid is not considered.…”

Section: Introductionmentioning

confidence: 99%

On the Validity of the Relationship 1/T = 1/TB+1/TS+1/TD in NMR Techniques With Regards to Permeability Estimation of Natural Porous Media

et al. 2021

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One of the most relevant feature of geophysical techniques based on nuclear magnetic resonance is their ability to estimate the permeability of natural porous media, since other geophysical techniques, as the use of the formation factor and neutron well-logs, allow to quantify the volume of water in the media. Permeability is conventionally obtained from decay time of the total resonance signal. However, the fluid in the pores of a medium normally has different mobility degree that can be differentiated by the NMR results. Therefore, a detailed estimation of permeability requires decomposing the total resonance signal as a function of the decay times corresponding to the three mechanisms that contribute to the signal: the intergranular free fluid, the surface layer, and the diffusion relaxation mechanism. The relationship currently used to make this decomposition states that the exponential decay rate attributed to the total resonance signal is the sum of the three existing decay rates. We demonstrate that this relationship is not generally applicable in porous media, showing the contradiction with the much more widely accepted relationships as well as computation examples from three typical decay rates in a single pore and from sandstone with bulk and surface relaxation mechanisms. Consequently, we conclude that the assertion whereby the permeability of any porous medium does not depend on the decay time of the free fluid is an overstatement, since it only applies to very small pore sizes.

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Section: Introductionmentioning

confidence: 99%

On the Validity of the Relationship 1/T = 1/TB+1/TS+1/TD in NMR Techniques With Regards to Permeability Estimation of Natural Porous Media

et al. 2021

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Magnetic Resonance Relaxation in Heterogeneous Materials is Analogous to First-Order Chemical Reaction

Afrough

2024

Transp Porous Med

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Biological tissue, pharmaceutical tablets, wood, porous rocks, catalytic reactors, concrete, and foams are examples of heterogeneous systems that may contain one or several fluid phases. Fluids in such systems carry chemical species that may participate in chemical reactions in the bulk of a fluid, as homogeneous reactions, or at the fluid/fluid or fluid/solid interfaces, as heterogeneous reactions. Magnetic resonance relaxation measures the return of 1H nuclear magnetization in chemical species of these fluids to an equilibrium state in a static magnetic field. Despite the perceived difference between reaction–diffusion and relaxation–diffusion in heterogeneous systems, similarities between the two are remarkable. This work draws a close parallel between magnetic resonance relaxation–diffusion and chemical reaction–diffusion for elementary unitary reaction $${\text{A}}\to {\text{B}}$$ A → B in a dilute solution—both in heterogeneous systems. A striking similarity between the dimensionless numbers that characterize their relevant behavior is observed: the Damköhler number of the second kind $${{\text{Da}}}^{{\text{II}}}$$ Da II for reaction and the Brownstein–Tarr number $${{\text{BT}}}_{i}$$ BT i for relaxation. The new vision of analogy between reaction- and magnetic resonance relaxation–diffusion in heterogeneous systems encourages the exploitation of similarities between reaction and relaxation processes to noninvasively investigate the dynamics of chemical species and reactions. One such example of importance in chemical engineering is provided for solid–fluid reaction in packed beds.

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Nuclear spin relaxation

Kowalewski¹

2020

Nuclear Magnetic Resonance

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The review covers the progress in the field of NMR relaxation in fluids primarily during 2019. Since the topic is returning to this volume SPR after a break of a few years, some highlights of the relaxation literature from the period 2014–18 are mentioned. The emphasis is on comparatively simple liquids and solutions of physico-chemical and chemical interest, as in previous periods, but selected biophysics-related topics (including some work on relaxation in solid biomaterials) and relaxation-related studies on more complex systems (macromolecular solutions, liquid crystalline systems, glassy and porous materials) are also covered. Section 2 of the chapter is concerned with general, physical and experimental aspects of nuclear spin relaxation, while Section 3 is concentrated on applications.

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A two-region transport model for interpreting T1-T2 measurements in complex systems

Cited by 4 publications

References 30 publications

On the Validity of the Relationship 1/T = 1/TB+1/TS+1/TD in NMR Techniques With Regards to Permeability Estimation of Natural Porous Media

On the Validity of the Relationship 1/T = 1/TB+1/TS+1/TD in NMR Techniques With Regards to Permeability Estimation of Natural Porous Media

Magnetic Resonance Relaxation in Heterogeneous Materials is Analogous to First-Order Chemical Reaction

Nuclear spin relaxation

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