A Bulk and Spatially Resolved NMR Relaxation Study of Sandstone Rock Plugs

Roberts, S; McDonald, P.J.; Pritchard, Tim

doi:10.1006/jmra.1995.0007

Cited by 31 publications

(23 citation statements)

References 4 publications

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“…Therefore, can increase linearly from 10 Ϫ3 to 10 2 m s Ϫ1 for solids with increasing surface concentrations of Fe(III). This variation is as great as the variation typically observed for pore size distribution in natural geological materials (34). We have also found that NMR relaxation measurements are so sensitive to paramagnetic impurities that most natural samples will probably have values above 1 m s Ϫ1 .…”

Section: Discussionmentioning

confidence: 94%

Paramagnetic Effects of Iron(III) Species on Nuclear Magnetic Relaxation of Fluid Protons in Porous Media

Bryar

Daughney

Knight

2000

Journal of Magnetic Resonance

124

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Section: Discussionmentioning

confidence: 94%

Paramagnetic Effects of Iron(III) Species on Nuclear Magnetic Relaxation of Fluid Protons in Porous Media

Bryar

Daughney

Knight

2000

Journal of Magnetic Resonance

124

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“…In general, 1 H NMR relaxometry is utilized in a broad scientific range as a way to determine the state of water e.g. in food samples (Regier et al, 2004), biopolymers (Hills, 1992), biofilms (Beuling et al, 1998) or granular sludge (Lens et al, 1999), as well as to determine pore size distributions in coals (Glaves et al, 1988), sandstone rock plugs (Roberts et al, 1995) and silica materials (Hinedi et al, 1997). 1 H NMR relaxometry is also used in many petrophysical applications (Kenyon, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…In this context, the solid bulk concentration of the mineral is not the relevant parameter, since a paramagnetic atom buried even one atomic layer deep in the solid is expected not to contribute to the surface relaxivity (Kleinberg et al, 1994). Literature reveals surface relaxivity values for minerals ranging from~10 )3 lm s )1 for cleaned silica gel (Bryar et al, 2000), 0.8 lm s )1 for quartz (Kenyon and Kolleeny, 1995), 1.8-3.3 lm s )1 for clays (Matteson et al, 2000) and~3 lm s )1 for silica sand (Hinedi et al, 1997) to 9-46 lm s )1 for sandstone rocks (Roberts et al, 1995). For quartz and silica materials, very low concentrations in the ppm-range of Fe(III)-bearing solid phases, presented as surface coatings or as separate mineral grains, were able to increase the surface relaxivity as much as two orders of magnitude (Bryar et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

1H NMR Relaxometry in Natural Humous Soil Samples: Insights in Microbial Effects on Relaxation Time Distributions

2006

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1 H NMR relaxometry is applied for the investigation of pore size distributions in geological substrates. The transfer to humous soil samples requires the knowledge of the interplay between soil organic matter, microorganisms and proton relaxation. The goal of this contribution is to give first insights in microbial effects in the 1 H NMR relaxation time distribution in the course of hydration of humous soil samples. We observed the development of the transverse relaxation time distribution of the water protons after addition of water to air dried soil samples. Selected samples were treated with cellobiose to enhance microbial activity. Besides the relaxation time distribution, the respiratory activity and the total cell counts were determined as function of hydration time. Microbial respiratory activities were 2-15 times higher in the treated samples and total cell counts increased in all samples from 1Â10 9 to 5Â10 9 cells g )1 during hydration. The results of 1 H NMR relaxometry showed tri-, bi-and mono-modal relaxation time distributions and shifts of peak relaxation times towards lower relaxation times of all investigated soil samples during hydration. Furthermore, we found lower relaxation times and merging of peaks in soil samples with higher microbial activity. Dissolution and hydration of cellobiose had no detectable effect on the relaxation time distributions during hydration. We attribute the observed shifts in relaxation time distributions to changes in pore size distribution and changes in spin relaxation mechanisms due to dissolution of organic and inorganic substances (e.g. Fe 3+ , Mn 2+ ), swelling of soil organic matter (SOM), production and release of extracellular polymeric substances (EPS) and bacterial association within biofilms.Abbreviations: 1 H NMR -Proton Nuclear Magnetic Resonance; q 0 -initial mean surface relaxivity; d pore ¼ 4V 0 S 0 -pore diameter of a cylindrical pore (Hinedi et al., 1997); T 2 -initial mean relaxation time; q i ¼ k T iS -surface relaxivity; d 0 -initial mean pore diameter; k-layer thickness, in which T iS takes place; DAPI--4¢,6-diamidino-2-phenylindol; d BET -mean pore diameter estimated from BET data; DOCDissolved Organic Carbon; EPS -extracellular polymeric substances; PGA -polygalacturonic acid; S 0 -water covered pore surface; S BET -specific surface area estimated from BET data; SOM -soil organic matter; t -hydration time [days], s-time constant of the first order process [days]; T i -relaxation time of the longitudinal (i=1) or transverse (i=2) relaxation of proton magnetization; T iB -bulk relaxation time;T iS -surface relaxation time; V 0 -water filled pore volume; Y -replacement character for the peak relaxation time [ms]; Y ¥ -peak relaxation time for infinite hydration time; Y 0 -initial value for t=0.

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“…stone with decreased local relative humidity. Indeed, this shortening can be used to characterise the pore structure when the relative humidity is known [7,8].…”

Section: Experiments 2-water Penetration Into Untreated Sandstonementioning

confidence: 99%

The use of magnetic resonance imaging techniques in assessing the uptake of surface treatments and water movement through stone faces

et al. 1998

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This paper addresses some practical questions regarding the influence of hydrophobic treatments on the movement of water in sandstone. The broad line gradient echo magnetic resonance imaging technique has been used for monitoring the depth of penetration of alkyl alkoxysilane treatment into untreated sandstone and subsequently to visualise the movement and spatial distribution profile of water in the untreated and silane treated sandstone matrix. The experimental results show that the effect of hyrdrophobic treatment depends on whether the stone is in short-term or prolonged contact with water. For short term exposure, the presence of a silane treatment prevents the movement of water into and out of the sandstone matrix. However, after continuous long-term contact with water the hydrophobic treatment is unable to prevent the ingress and internal redistribution of water. The ability of water to infiltrate treated regions of sandstone has significant practical implication for stone structures where deterioration may be due to outward movement of water from the interior to the surface of the stone matrix

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A Bulk and Spatially Resolved NMR Relaxation Study of Sandstone Rock Plugs

Cited by 31 publications

References 4 publications

Paramagnetic Effects of Iron(III) Species on Nuclear Magnetic Relaxation of Fluid Protons in Porous Media

Paramagnetic Effects of Iron(III) Species on Nuclear Magnetic Relaxation of Fluid Protons in Porous Media

1H NMR Relaxometry in Natural Humous Soil Samples: Insights in Microbial Effects on Relaxation Time Distributions

The use of magnetic resonance imaging techniques in assessing the uptake of surface treatments and water movement through stone faces

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