A study to apply nuclear magnetic resonance porosity measurements to seabed sediments

Bortolotti, Villiam; Gombia, Mirko; Cernich, F.; Michelozzi, Enzo; Fantazzini, Paola

doi:10.1016/j.margeo.2006.03.014

Cited by 4 publications

(5 citation statements)

References 6 publications

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“…Porosity can be measured in various ways with MRI and NMR, and the results are in general within a few percent of the porosity measured destructively with conventional methods (Bortolotti et al, 2006;Marica et al, 2006) as in this paper. In sedimentology and geomorphology this could be employed for the mapping of ground ice in cores, vugs, macropores and roots with relevance for groundwater flow and infiltration.…”

Section: Potential Applications and Limitationsmentioning

confidence: 52%

“…2. Sedimentary structures and variability of pore space in cores were often mapped with MRI for core diameters up to 8 cm (Bortolotti et al, 2006;Marica et al, 2006) and are relatively easy and straightforward, because the sample is immobile and can be exposed as long as necessary for accurate high-density imaging. The basic limitation is the maximum size of the sample that can be placed in the MRI instrument.…”

Section: Potential Applications and Limitationsmentioning

confidence: 99%

“…Materials with water-or hydrocarbonfilled voids have been mapped in detail, such as in vugular carbonates (Borgia et al, 1996), sedimentary structure (by mapping pore structure) in seabed cores (Bortolotti et al, 2006) and sandstone cores (Marica et al, 2006), and sea-ice pore structures filled with brine (Eicken et al, 2000). Mapping of flow velocity through porous media has also been accomplished with MRI (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic Resonance Imaging of coarse sediment

Kleinhans

Jeukens

Bakker

et al. 2008

Sedimentary Geology

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Section: Potential Applications and Limitationsmentioning

confidence: 52%

Section: Potential Applications and Limitationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Magnetic Resonance Imaging of coarse sediment

Kleinhans

Jeukens

Bakker

et al. 2008

Sedimentary Geology

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“…It can be measured directly from plugs based on bulk and skeletal densities, gas expansion, displacement techniques (Schön, 2011), or indirectly in wells using; neutron, density and sonic log data. Recently, nuclear magnetic resonance method is also used to obtain the porosity (Bortolotti et al, 2006;Dillinger and Esteban, 2014;El Sayed and El Sayed, 2016). The density and the inferred porosity, so called Helium-porosity of samples were carried out using a gas Helium pycnometer of Micrometrics AccuPyc II 1340 type.…”

Section: Density and Porosity Measurementsmentioning

confidence: 99%

A Preliminary study of relationships between thermal conductivity and petrophysical parameters in Hamra Quartzites reservoir, Hassi Messaoud field (Algeria)

Zerrouki

Géraud

Diraison

et al. 2019

Journal of African Earth Sciences

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In geothermic studies, the thermal conductivity (TC) is an essential parameter needed to calculate heat flow in rocks. It is obtained generally with high accuracy from laboratory measurements. The methodology proposed in this paper is to estimate the TC, which depends on many parameters; such as mineralogy, porosity, shape of voids and nature of contact between grains, based on linear and nonlinear relationships. In order to predict the thermal conductivity from other petrophysical parameters in the Hamra Quartzites reservoir, we have measured porosity, density and permeability, for dry samples taken from core wells. The correlation coefficients (R) were calculated between thermal conductivity and other petrophysical parameters for all samples. The results show that, the correlation coefficient is moderate between TC and the porosity, weak between TC, density and permeability. To improve these correlations, samples were classified into cemented and uncemented sets. A minor improvement on the correlation coefficients is noted between TC, density and porosity in uncemented samples, with values equal 0.51 and 0.73, respectively. The application of Radial Basis Function (RBF) neural networks, using density, porosity and permeability as inputs and thermal conductivity as output, permit us to predict the thermal conductivity with high precision. The correlation coefficient between TC estimated by the RBF neural network is the same as that measured in laboratory equaling 0.983.

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“…The relaxation, or the return to equilibrium position, can be quantitatively measured. The signal acquired during relaxation process contains information both on the density of nuclei 1 H, from which can be obtained the porosity, and on the properties of the pore space, which can be extracted from the T1 and T2 relaxation time constants (Bortolotti et al, 2006b).…”

Section: Introductionmentioning

confidence: 99%

Application of Magnetic Resonance Techniques to evaluate soil compaction after grazing

Carrero-González¹,

Cruz²,

Martínez³

2012

J. Soil Sci. Plant Nutr.

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Grazing constitutes one of the most important processes of soil degradation due to compaction, and it affects both vegetation and soil in arid and semiarid ecosystems. Compaction modifies the soil structure and causes an increase in the proportion of small aggregates, which consequently leads to an increase in bulk soil density. Compaction also produces a decrease in soil organic carbon content. The soil becomes more densely packed, causing reductions in porosity and storage capacity. Magnetic Resonance Imaging (MRI) was used to obtain a relative estimate of soil water content and porosity. The signal intensity from proton density images, which corresponds to the amount of water present in a sample, is lower in compacted soil. As calculated from the image signal intensity, the porosity percentage is also lower in grazing soils in comparison with natural recovery soils. H NMR relaxometry studies demonstrate shorter T2 and T1 relaxation times in grazing soil samples, suggesting lower pore sizes in these soils. Moreover, the grazing samples have a monomodal distribution of T1 with a narrow band, indicating greater homogeneity in the pore sizes. The bimodal distribution of T2 complements this result and indicates a greater proportion of smaller-size pores with greater homogeneity between them. There is a significant positive correlation between the porosity values determined by both methods, which demonstrates the validity of the MR technique. The relaxation times also show positive and significant correlations with analytical porosity. The application of MR techniques to soil compaction studies demonstrated the natural recovery of the physical properties of deteriorated soil after grazing damage in pastoral systems brought about by complete animal exclusion for ten years.

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A study to apply nuclear magnetic resonance porosity measurements to seabed sediments

Cited by 4 publications

References 6 publications

Magnetic Resonance Imaging of coarse sediment

Magnetic Resonance Imaging of coarse sediment

A Preliminary study of relationships between thermal conductivity and petrophysical parameters in Hamra Quartzites reservoir, Hassi Messaoud field (Algeria)

Application of Magnetic Resonance Techniques to evaluate soil compaction after grazing

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