Dispersion of T1 and T2 Nuclear Magnetic Resonance Relaxation in Crude Oils

Chen, Joseph J.; Hürlimann, Martin D.; Paulsen, Jeffrey L.; Freed, Daniel S.; Mandal, Soumyajit; Song, Yi‐Qiao

doi:10.1002/cphc.201402077

Cited by 24 publications

(28 citation statements)

References 37 publications

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“…Similar results have been obtained with another dynamical model of hydrocarbons within asphaltene aggregates in crude oils [129]. For a heteronuclear (I-S) dipolar relaxation process mediated by 1D translational diffusion, 1/T 2 and 1/T 1 are proportional to the following linear combinations of the spectral densities at the nuclear (x I ) and electronic (x S = 659x I ) Larmor frequencies:…”

Section: Comparison With the Observed Viscosity Dependencies Of T 1 Asupporting

confidence: 82%

Multiscale nuclear magnetic relaxation dispersion of complex liquids in bulk and confinement

Korb

2018

Progress in Nuclear Magnetic Resonance Spectroscopy

144

161

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The nuclear magnetic relaxation dispersion (NMRD) technique consists of measurement of the magnetic-field dependence of the longitudinal nuclear-spin-lattice relaxation rate 1/T. Usually, the acquisition of the NMRD profiles is made using a fast field cycling (FFC) NMR technique that varies the magnetic field and explores a very large range of Larmor frequencies (10 kHz < ω/(2π) <40 MHz). This allows extensive explorations of the fluctuations to which nuclear spin relaxation is sensitive. The FFC technique thus offers opportunities on multiple scales of both time and distance for characterizing the molecular dynamics and transport properties of complex liquids in bulk or embedded in confined environments. This review presents the principles, theories and applications of NMRD for characterizing fundamental properties such as surface correlation times, diffusion coefficients and dynamical surface affinity (NMR wettability) for various confined liquids. The basic longitudinal and transverse relaxation equations are outlined for bulk liquids. The nuclear relaxation of a liquid confined in pores is considered in detail in order to find the biphasic fast exchange relations for a liquid at proximity of a solid surface. The physical-chemistry of liquids at solid surfaces induces striking differences between NMRD profiles of aprotic and protic (water) liquids embedded in calibrated porous disordered materials. A particular emphasis of this review concerns the extension of FFC NMR relaxation to industrial applications. For instance, it is shown that the FFC technique is sufficiently rapid for following the progressive setting of cement-based materials (plasters, cement pastes, concretes). The technique also allows studies of the dynamics of hydrocarbons in proximity of asphaltene nano-aggregates and macro-aggregates in heavy crude oils as a function of the concentration of asphaltenes. It also gives new information on the wettability of petroleum fluids (brine and oil) embedded in shale oil rocks. It is useful for understanding the relations and correlations between NMR relaxation times T and T, diffusion coefficients D, and viscosity η of heavy crude oils. This is of particular importance for interpreting T, T, 2D T-T and D-T correlation spectra that could be obtained down-hole, thus giving a valuable tool for investigating in situ the molecular dynamics of petroleum fluids. Another domain of interest concerns biological applications. This is of particular importance for studying the complex dynamical spectrum of a folded polymeric structure that may span many decades in frequency or time. A direct NMRD characterization of water diffusional dynamics is presented at the protein interface. NMR experiments using a shuttle technique give results well above the frequency range accessible via the FFC technique; examples of this show protein dynamics over a range from fast and localized motions to slow and delocalized collective motions involving the whole protein. This review ends by an interpretation of the origin of the proto...

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Section: Comparison With the Observed Viscosity Dependencies Of T 1 Asupporting

confidence: 82%

Multiscale nuclear magnetic relaxation dispersion of complex liquids in bulk and confinement

Korb

2018

Progress in Nuclear Magnetic Resonance Spectroscopy

144

161

View full text Add to dashboard Cite

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“…In quantitative studies, the EPR signal is found to correlate with the asphaltene content. The NMR relaxation properties of liquid components in oil, the so-called maltenes, were likewise found to correlate with the asphaltene content [43,44], suggesting that the latter contain the largest amount of unpaired electrons in crude oil, and therefore act as a relaxation agent in analogy to contrast agents in aqueous solution. Current literature concludes that free, delocalized electrons and vanadyl ions (VO 2+ ) constitute the major contributions to the EPR spectrum, though their relative proportion varies greatly.…”

Section: Introductionmentioning

confidence: 96%

Quantifying Crude Oil Contamination in Sand and Soil by EPR Spectroscopy

et al. 2021

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Crude oil frequently contains stable radicals that allow detection by means of EPR spectroscopy. On the other hand, most sands and soils possess significant amounts of iron, manganese or other metallic species that often provide excessively broad EPR signatures combined with well-defined sharp features by quartz defects. In this study, we demonstrate the feasibility to identify oil contamination in natural environments that are subject to oil spillage during production on land, as well as beachside accumulation of marine oil spillage. Straightforward identification of oil is enabled by the radical contributions of asphaltenes, in particular by vanadyl multiplets that are absent from natural soils. This potentially allows for high-throughput soil analysis or the application of mobile EPR scanners.

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“…Since the interacting dipoles are located on different molecules, the intermolecular interaction between maltenes and asphaltenes becomes important for the maltenes’ relaxation. In addition, the self-aggregated structures of asphaltene molecules in crude oil or asphaltene-solvent solutions interfere with the motions of the maltenes, slowing them down so that the reorientations of the maltenes no longer fulfill the extreme narrowing limit, and

ratios larger than one and a frequency dependence of

are observed [ 27 ]. Investigations of maltenes’ relaxation in the presence of asphaltenes show faster relaxation with higher asphaltene content and a stronger increase in the transverse than the longitudinal relaxation rate [ 13 , 19 ].…”

Section: Theorymentioning

confidence: 99%

Non-Exponential 1H and 2H NMR Relaxation and Self-Diffusion in Asphaltene-Maltene Solutions

et al. 2021

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The distribution of NMR relaxation times and diffusion coefficients in crude oils results from the vast number of different chemical species. In addition, the presence of asphaltenes provides different relaxation environments for the maltenes, generated by steric hindrance in the asphaltene aggregates and possibly by the spatial distribution of radicals. Since the dynamics of the maltenes is further modified by the interactions between maltenes and asphaltenes, these interactions—either through steric hindrances or promoted by aromatic-aromatic interactions—are of particular interest. Here, we aim at investigating the interaction between individual protonic and deuterated maltene species of different molecular size and aromaticity and the asphaltene macroaggregates by comparing the maltenes’ NMR relaxation (T1 and T2) and translational diffusion (D) properties in the absence and presence of the asphaltene in model solutions. The ratio of the average transverse and longitudinal relaxation rates, describing the non-exponential relaxation of the maltenes in the presence of the asphaltene, and its variation with respect to the asphaltene-free solutions are discussed. The relaxation experiments reveal an apparent slowing down of the maltenes’ dynamics in the presence of asphaltenes, which differs between the individual maltenes. While for single-chained alkylbenzenes, a plateau of the relaxation rate ratio was found for long aliphatic chains, no impact of the maltenes’ aromaticity on the maltene–asphaltene interaction was unambiguously found. In contrast, the reduced diffusion coefficients of the maltenes in presence of the asphaltenes differ little and are attributed to the overall increased viscosity.

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Dispersion of T₁ and T₂ Nuclear Magnetic Resonance Relaxation in Crude Oils

Cited by 24 publications

References 37 publications

Multiscale nuclear magnetic relaxation dispersion of complex liquids in bulk and confinement

Multiscale nuclear magnetic relaxation dispersion of complex liquids in bulk and confinement

Quantifying Crude Oil Contamination in Sand and Soil by EPR Spectroscopy

Non-Exponential 1H and 2H NMR Relaxation and Self-Diffusion in Asphaltene-Maltene Solutions

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