Cryoporometry and relaxometry of water in silica-gels

Valckenborg, Rme Roland; Pel, Leo L; Kopinga, K.

doi:10.1016/s0730-725x(01)00275-2

Cited by 23 publications

(15 citation statements)

References 4 publications

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“…Both parameters are known to affect the freezing temperature (Valckenborg et al, 2001). In conditions where bulk water can be selectively frozen, it is possible to make a distinction from the relaxation time values considering the great difference in mobility of the protons of ice (T * 2 = 5-15 μs) and of non-freezing water in a semi-liquid state.…”

Section: Nmr Results On Consolidated Water-saturated Porous Clay Sammentioning

confidence: 99%

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Montavon

Guo

Tournassat

et al. 2009

Geochimica et Cosmochimica Acta

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. Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study. Geochimica et Cosmochimica Acta, Elsevier, 2009, 73 (24) AbstractThe aim of the present work was to quantify accessible porosities for iodide and for a water tracer (HTO) on water-saturated compacted clay samples (illite, montmorillonite and MX-80 bentonite) and to relate these macroscopic values to the forms of water in these porosities (surface/bulk water, external/internal water). Low field proton NMR was used to characterize and quantify the forms of water. This enabled the three different populations (structural OH, external surface and internal surface water) to be differentiated on hydrated clays by considering the difference in proton mobility. An accurate description of the water forms within the different populations did not appear possible when water molecules of these populations were in contact because of the occurrence of rapid exchange reactions. For this 2 reason, it was not possible to use the low resolution NMR method to quantify external surface and bulk water in fully water-saturated compacted clay media at room temperature. This latter information could however be estimated when analyzing the samples at -25°C. At this temperature, a distinction based on the difference in mobility could be made since surface water remained in a semi-liquid state whereas bulk water froze. In parallel, accessible porosities for anions and HTO were determined by an isotopic dilution method using capillaries to confine the materials. HTO was shown to probe the whole pore volume (i.e. the space made of surface and bulk water). When the surface water volume was mainly composed of interlayer water (case of montmorillonite and bentonite), iodide was shown to be located in the pore space made of bulk water. When the interlayer water was not present (case of illite), the results showed that iodide could access a small fraction of the surface water volume localized at the external surface of the clay particles.

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Section: Nmr Results On Consolidated Water-saturated Porous Clay Sammentioning

confidence: 99%

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Montavon

Guo

Tournassat

et al. 2009

Geochimica et Cosmochimica Acta

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“…Our observation of the almost independence of T 2 on temperature below −4 °C for shale samples (Figure 1) is inconsistent with the longstanding surface relaxation assumption. 11,15,18,20,21,30 For example, Mitchell et al 30 and Valckenborg et al 15 reported systematic shifts in T 2 as a function of temperature. Moreover, ILT for NMRR inherently forces PSD to have a Gaussian-type distribution.…”

Section: Energy and Fuelsmentioning

confidence: 99%

Characterization of Nanoporous Systems in Gas Shales by Low Field NMR Cryoporometry

Zhou

Han²,

Yang³

2016

Energy Fuels

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Shale gas and oil is an increasingly important source of unconventional energy. Shale gas and oil reservoirs differ from their conventional counterparts mainly in the nanoporous structures of the former, which play a critical role not only for the resource estimation but also for the shale gas/oil extraction and development. However, the traditional methods for characterizing rock porosities, such as gas sorption (the Brunauer−Emmett−Teller technique, BET), mercury intrusion porosimetry (MIP), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), cannot satisfactorily and adequately measure and characterize the nanoporous structures. Nuclear magnetic resonance (NMR) spectroscopy is known for its sensitivity to local environments at the atomic level and, therefore, can provide an alternative method for the investigation of nanoporous structures in gas shales. This study has refined the low field NMR cryoporometry (NMRC) method and applied it along with other methods such as NMR relaxometry (NMRR) to measure and characterize the nanoporous structures (i.e., the pore size distribution, PSD) of selected shale samples from the Sinian-Cambrian-Ordovician strata at the Low Yangzi Plateau, China. Our NMRC measurements of a controlled porous glass (CPG) and shale samples show that the organic compound octamethylcyclotetrasiloxane (OMCTS) is a superior NMR probe liquid in terms of improved spectral resolution and signal/ noise (S/N) ratio. Comparisons of the NMRC shale PSD results with those from NMRR and gas sorption show that NMRC is an independent and effective method for determining the distribution of nanosized pores in gas shales. Moreover, important parameters such as porosity can also be estimated from the low field NMR cryoporometry.

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“…Diffusion, relaxation, NMR cryoporometry (NMRC) and magnetic resonance imaging (MRI) measurements of fluids adsorbed in porous materials provide detailed information about the pore size distribution, morphology, transport and adsorption phenomena, as well as chemical exchange [11,12,13,14,15,16,17]. NMR relaxometry has been exploited to characterize porous structures of cements and shale [18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33]. Variabletemperature MRI of freezing water was also successfully employed to observe the spatially resolved pore size distribution in cements [34].…”

Section: Introductionmentioning

confidence: 99%

Characterization of pore structures of hydrated cements and natural shales by 129 Xe NMR spectroscopy

Zhou

Komulainen

Vaara

et al. 2017

Microporous and Mesoporous Materials

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129 Xe NMR of adsorbed xenon gas is a sensitive tool for the characterization of porous materials. Here we exploit, for the first time, 129 Xe NMR to investigate the nanoscale porous structures in hydrated white cements and natural shale. Signals of xenon in mesopores and larger voids are well resolved in the spectra of the cement samples, and the exchange rate between these sites was determined to be 100−300 s-1 at room temperature. The spectra imply that the mesopore size is the smallest and the exchange rate is the highest in the sample with the lowest initial water/cement ratio. The heat of adsorption of xenon in the cements is similar to that in silica gels, about 12 kJ/mol. The shale spectra include a very broad signal, covering a range of about 600 ppm, implying that the adsorbed xenon interacts with the paramagnetic impurities present in the samples.

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Cryoporometry and relaxometry of water in silica-gels

Cited by 23 publications

References 4 publications

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

Characterization of Nanoporous Systems in Gas Shales by Low Field NMR Cryoporometry

Characterization of pore structures of hydrated cements and natural shales by 129 Xe NMR spectroscopy

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