scholarly journals Robust Lp-Norm Inversion for High-Resolution Fluid Contents from Nuclear Magnetic Resonance Measurements

2021 ◽  
Vol 11 (23) ◽  
pp. 11298
Author(s):  
Houzhu Zhang ◽  
Jinhong Chen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
High Spatial Resolution ◽  
Inversion Algorithm ◽  
Fluid Content ◽  
Petrophysical Property ◽  
Property Estimation ◽  
Lp Norm ◽  
Nmr Data ◽  
Nuclear Magnetic

Fluid content computed from nuclear magnetic resonance (NMR) has proved to be an accurate and reliable tool for petrophysical property estimation. To overcome the limitations of conventional NMR measurements, high spatial resolution NMR (HSR-NMR) has been introduced to achieve the desired resolution for cores of any size. However, inversion of fluid contents from HSR-NMR data suffers from nonreliable measurements at the ends of the cores due to the heterogeneities of the magnetic fields caused by the relatively small size of the coil. A robust Lp-norm inversion algorithm, developed for geophysical inverse problems, has been implemented and applied on the inversion of NMR measurements. The estimated fluid content from Lp inversion matches well with the kerogen content in the cores both visually and quantitively. The resolution of the inverted fluid contents is as high as 1 inch. Further testing on the raw data with large derivations demonstrated that reliable results can only be achieved by using Lp inversion with low p’s values within the range of (1, 1.1].

15N and 13C nuclear magnetic resonance of deoxydinucleotide monophosphates. II. Protonation of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine in dimethyl sulfoxide

1990 ◽  
Vol 68 (11) ◽  
pp. 2033-2038 ◽  
Author(s):  
Giovanna Barbarella ◽  
Massimo Luigi Capobianco ◽  
Luisa Tondelli ◽  
Vitaliano Tugnoli
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Dimethyl Sulfoxide ◽  
Phosphate Group ◽  
Nmr Data ◽  
13C Nuclear Magnetic Resonance ◽  
C Nmr ◽  
Nuclear Magnetic

The preferential protonation sites of the homo dimers deoxycytidylyl-(3′,5′)-deoxycytidine, thymidylyl-(3′,5′)-thymidine, and deoxyadenylyl-(3′,5′)-deoxyadenosine were established by nitrogen-15 and carbon-13 NMR in dimethyl sulfoxide, in the presence of varying amounts of CF3COOH. The nitrogen-15 NMR data show that in d(CpC) the capability of the two N3 nitrogens to accept the proton is slightly different. In d(TpT) and d(ApA) the protonation of the phosphate group leads to significant variations of the chemical shift of the carbons adjacent to phosphorus. Keywords: deoxydinucleotides, protonation, 15N and 13C NMR.

Perfluoroalkyl- and fluoroalkyl- complexes of rhodium(III)

1976 ◽  
Vol 54 (13) ◽  
pp. 2077-2084 ◽  
Author(s):  
Howard C. Clark ◽  
Kenneth J. Reimer
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Infrared Spectra ◽  
Oxidative Addition ◽  
Far Infrared ◽  
Addition Reactions ◽  
Nmr Data ◽  
Far Infrared Spectra ◽  
Nuclear Magnetic

A series of perfluoroalkyl (Rf—) and fluoroalkyl (RfCH2—) complexes of rhodium(III) have been prepared by oxidative addition reactions of RfI and RfCH2I (Rf = CF3, C2F5 and C3F7) with trans-RhClCO(PMe2Ph)2. The reaction of CF3I with trans-RhClCO(PMePH2)2 gave RhClI(CF3)CO(PMePh2)2 but no reaction was observed with CF3CH2I. The trans stereochemistry of addition has been assigned to all complexes by nuclear magnetic resonance measurements and the comparison of the far-infrared spectra to those of some bromo compounds: RhBrI(CF3)CO(PMe2Ph)2 and RhBrI(C3F7CH2)CO(PMe2Ph)2. Both 1H and 19F nmr data are presented and discussed.

Case study of quantification of oil viscosity and saturation in complex reservoirs using advanced nuclear magnetic resonance log interpretation techniques

2011 ◽  
Vol 51 (2) ◽  
pp. 725
Author(s):  
Adrian Manescu ◽  
Keith Boyle
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Clay Content ◽  
Hydrocarbon Exploration ◽  
Fluid Viscosity ◽  
Oil Viscosity ◽  
Porosity Distribution ◽  
Nmr Data ◽  
Log Interpretation ◽  
Nuclear Magnetic

In the hydrocarbon exploration process, after a prospect has been identified and an exploration well has been drilled, a critical piece of information is the oil type. Earlier wireline or while-drilling well-logging technologies provided rock properties and saturation information, but relied on expensive sampling and testing to determine oil properties. This weakness was overcome through the introduction of nuclear magnetic resonance (NMR) logs that can provide formation properties—lithology-independent porosity, porosity distribution, permeability, etcetera—and information about the reservoir fluid viscosity. NMR data were recently acquired in complex, high-clay content, low-salinity oil reservoirs. Traditional petrophysical interpretations throughout these reservoirs were confronted with a complex lithology—comprising feldspathic litharenites and volcanic lithic components—high clay content and low formation water salinity, of 3-4 Kppm NaCl eq. This extended abstract shows how acquisition and interpretation of NMR data not only provided porosity and porosity distribution, but also identified oil viscosity across the logged intervals. Advanced NMR log interpretation techniques (2D-NMR maps of diffusion (D) versus T2, int) were used to identify oil NMR signal. This technique produced a continuous profile of diffusion and intrinsic T2 distribution maps. Once the oil NMR signal was identified, an estimation of the oil viscosity was also possible because D and T2, int are related with viscosity. Several available correlations have been used and results were comparable with production data.

scholarly journals The value of universally available raw NMR data for transparency, reproducibility, and integrity in natural product research

2019 ◽  
Vol 36 (1) ◽  
pp. 35-107 ◽  
Author(s):  
James B. McAlpine ◽  
Shao-Nong Chen ◽  
Andrei Kutateladze ◽  
John B. MacMillan ◽  
Giovanni Appendino ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Natural Product ◽  
Research Community ◽  
Raw Data ◽  
Nmr Data ◽  
Natural Product Research ◽  
Scientific Value ◽  
Nuclear Magnetic

With contributions from the global natural product (NP) research community, and continuing the Raw Data Initiative, this review collects a comprehensive demonstration of the immense scientific value of disseminating raw nuclear magnetic resonance (NMR) data, independently of, and in parallel with, classical publishing outlets.

Detection of Hydrogen in Bulk and Thin Film Silicon Dioxide by Hydrogen Nuclear Magnetic Resonance

1992 ◽  
Vol 284 ◽  
Author(s):  
D. H. Levy ◽  
K. K. Gleason
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Silicon Dioxide ◽  
Hydrogen Content ◽  
Solid State Nmr ◽  
Fused Silica ◽  
Nmr Data ◽  
Silica Material ◽  
Deep Ultraviolet ◽  
Nuclear Magnetic

ABSTRACTHydrogen is a common impurity in silicon dioxide (SiO2) which can influence its optical and electronic properites. Here, nuclear magnetic resonance (NMR) is applied to study of hydrogen in these materials, despite their relatively low hydrogen content. We present results for bulk fused silica as well as thermally grown films of SiO2 on silicon. These experiments demonstrate the potential of solid state NMR for studying low hydrogen content film systems. In bulk fused silica, we have observed that although the majority of hydrogen is isolated, a small number of centers exist involving adjacent silanol pairs. These pairs react during high temperature annealing as well as during deep ultraviolet irradiation. Furthermore, the presence of these centers is related to the susceptibility of fused silica to radiation damage. The results obtained on the fused silica material are compared to SiO2 films on silicon. The NMR spectra and relaxation associated with thick (>1μm) wet SiO2 films are similar to those for the fused silica while the NMR data for thinner oxide more closely resembles those of surface water on silica gel.

scholarly journals Surface nuclear magnetic resonance observations of permafrost thaw below floating, bedfast, and transitional ice lakes

Geophysics ◽  
2019 ◽  
Vol 84 (3) ◽  
pp. EN33-EN45 ◽  
Author(s):  
Andrew D. Parsekian ◽  
Andrea L. Creighton ◽  
Benjamin M. Jones ◽  
Christopher D. Arp
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Unfrozen Water ◽  
Lake Ice ◽  
Permafrost Thaw ◽  
Nmr Data ◽  
Unfrozen Water Content ◽  
Water Signal ◽  
Ice Conditions ◽  
Nuclear Magnetic

Lakes in Arctic systems contribute to hydrologic storage, biogeochemical cycling, and permafrost thaw. Here, we have used surface nuclear magnetic resonance (NMR) measurements on lakes of Alaska’s North Slope to investigate the extent of permafrost thaw below lakes with different annual ice conditions. Our purpose is to understand if annual lake ice conditions are related to development of thawed permafrost below lakes. We investigated 10 lakes and two terrestrial permafrost control sites using surface NMR and direct measurement under spring conditions when lake ice is nearly at its thickest. We did not observe unfrozen water below our surveyed bedfast ice lakes, whereas unfrozen water (indicating permafrost thaw) was measured below floating ice lakes. We found that transitional ice lakes, ones that alternate between floating and bedfast ice conditions over multiyear timescales depending on winter ice growth and lake level conditions, have complex vertical unfrozen water content profiles attributed to sporadic periods of thaw. Based on that finding, we speculate that predicting the presence of talik based on remotely sensed lake ice conditions is unreliable. We applied a scheme to subtract the lake water signal from the NMR data and found the resulting inversions to be improved.

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