A fast inversion method of 2D nuclear magnetic resonance based on the novel hybrid algorithm

To make up for the limitations and improve the accuracy of 1D nuclear-magnetic-resonance (NMR) logging in the evaluation of formation fluid properties, 2D NMR logging has become the focus of research. Increasing the sequence and inversion parameters of the 2D NMR can effectively improve the antinoise properties and resolution of the inversion, but at the same time, the reduced inversion speed and increased memory occupied will put forward higher requirements on the computer configuration and add to the cost of calculation, which poses challenges to the application of the traditional 2D NMR inversion algorithms. In view of the above defects, we have developed a new fast 2D NMR inversion LSQR-RSVD hybrid algorithm, and we have used the nonnegative least-squares (LSQR) calculation result as the initial value of the RSVD inversion. Taking oil-water and gas-water models as examples, the 2D NMR inversion effects of ( T2, D), ( T1, T2) are analyzed in detail, and ( T1, D) is also discussed by several groups of echo trains with variable echo interval ( TE) and waiting time ( TW). Compared to the inversion algorithm commonly used, the new hybrid algorithm can improve the inversion speed and significantly reduce the memory occupancy. Its remarkable advantages can further promote the application of 2D and even multidimensional NMR logging in practice.

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Nuclear-Magnetic-Resonance Petrophysics in Thin Sand/Shale Laminations

SPE Journal ◽

10.2118/102435-pa ◽

2010 ◽

Vol 16 (02) ◽

pp. 223-238 ◽

Cited By ~ 1

Author(s):

Chanh Cao Minh ◽

Padmanabhan Sundararaman

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Bimodal Distribution ◽

2D Nmr ◽

Fluid Type ◽

Antenna Aperture ◽

Nmr Logging ◽

Clay Layers ◽

Gas Bearing ◽

Nuclear Magnetic

Summary We discuss the use of nuclear-magnetic-resonance (NMR) logging in the petrophysical evaluation of thin sand/shale laminations. NMR helps detect thin beds, determine fluid type, establish the hydrocarbon type and volume if hydrocarbon is present, and, finally, determine the permeability of the sand layers (as opposed to that of the sand/shale system). Experiments were conducted on samples of 100% sand, 100% clay, and sand/clay layers with an NMR-logging tool at surface to verify the characteristic T2 bimodal relaxation distribution often observed in NMR logs that are acquired in thin beds. From the bimodal distribution, it is often possible to determine a cutoff to separate the productive sand layers from the shale layers and, with it, the porosity fraction of each component. Subsequently, the sand fraction, or net/gross ratio, can be estimated assuming that the 100%-sand porosity is known. Because gas, oil, and water have different NMR properties, fluid-typing techniques such as 2D NMR offer useful insights into the fluid type and properties in thin-layer sands. Because the laminations thickness is often less than the antenna aperture, the estimated permeability of the sand/ shale system will undercall the true permeability of the sand layers only. In this case, their permeability can be estimated quickly from Darcy's fluid-flow model. We show examples of thin sand/shale laminations that are oil-bearing and gas-bearing. In each case, the NMR detection was verified against borehole-imaging logs, and the fluid type in the sands was determined from multidimensional NMR analysis. The derived hydrocarbon volume was then compared with the results estimated from a triaxial induction tool. Permeability of the sand layers was also computed and compared to that of nearby thick sands. Core data in one well was used to validate NMR detection, porosity, permeability, and net sand thickness.

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New approaches of 3D nuclear magnetic resonance inversion for improving fluid typing

Interpretation ◽

10.1190/int-2015-0144.1 ◽

2016 ◽

Vol 4 (2) ◽

pp. SF67-SF79 ◽

Cited By ~ 5

Author(s):

Songhua Chen ◽

Wei Shao ◽

Ron Balliet

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Forward Modeling ◽

Inversion Method ◽

Improved Method ◽

3D Inversion ◽

Nmr Logging ◽

New Approaches ◽

2D And 3D ◽

Nuclear Magnetic

We have developed two new approaches for improving the efficiency and robostness of 2D and 3D inversion processing and interpretation from nuclear magnetic resonance (NMR) logging data. The first improved method consists of a dual-step inversion method to obtain [Formula: see text] and [Formula: see text] maps independently, rather than deriving one from the other. The second approach is an inversion-forward modeling-inversion technique for obtaining [Formula: see text] and [Formula: see text] maps using the same acquired data used for deriving [Formula: see text] and [Formula: see text] maps. Simulation results were evaluated to determine the improvement of the fluid typing interpretation and the robustness of the processing methods. Three actual wells of NMR logging data processing examples were also included to illustrate the utility of these methods for improving fluid typing involving various different combinations of reservoir fluids and mud filtrates.

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Nuclear Magnetic Resonance Spectroscopic Behaviour of Some Selective Natural Flavonoids: A Look Through

Mini-Reviews in Organic Chemistry ◽

10.2174/1570193x16666181224110603 ◽

2020 ◽

Vol 17 (2) ◽

pp. 185-196

Author(s):

Shyamal K. Jash ◽

Dilip Gorai ◽

Lalan C. Mandal ◽

Rajiv Roy

Keyword(s):

Nuclear Magnetic Resonance ◽

Natural Products ◽

Magnetic Resonance ◽

Hard Core ◽

2D Nmr ◽

Vital Role ◽

Spectral Technique ◽

Nmr Techniques ◽

Significant Class ◽

Nuclear Magnetic

Flavonoids are considered as a significant class of compounds among the natural products, exhibiting a variety of structural skeletons as well as multidirectional biological potentials. In structural elucidations of natural products, Nuclear Magnetic Resonance (NMR) spectroscopy has been playing a vital role; the technique is one of the sharpest tools in the hands of natural products chemists. The present resume deals with hard-core applications of such spectral technique, particularly in structural elucidation of flavonoids; different NMR techniques including 1H-NMR, 13C-NMR, and 2D-NMR [viz. 1H-1H COSY, COLOC, HMBC, HMQC] are described in detail.

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A New Hybrid Inversion Method for 2D Nuclear Magnetic Resonance Combining TSVD and Tikhonov Regularization

Journal of Imaging ◽

10.3390/jimaging7020018 ◽

2021 ◽

Vol 7 (2) ◽

pp. 18

Author(s):

Germana Landi ◽

Fabiana Zama ◽

Villiam Bortolotti

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Tikhonov Regularization ◽

Large Scale ◽

Regularization Parameter ◽

High Sensitivity ◽

Inversion Method ◽

Nmr Relaxometry ◽

Value Decomposition ◽

Nuclear Magnetic

This paper is concerned with the reconstruction of relaxation time distributions in Nuclear Magnetic Resonance (NMR) relaxometry. This is a large-scale and ill-posed inverse problem with many potential applications in biology, medicine, chemistry, and other disciplines. However, the large amount of data and the consequently long inversion times, together with the high sensitivity of the solution to the value of the regularization parameter, still represent a major issue in the applicability of the NMR relaxometry. We present a method for two-dimensional data inversion (2DNMR) which combines Truncated Singular Value Decomposition and Tikhonov regularization in order to accelerate the inversion time and to reduce the sensitivity to the value of the regularization parameter. The Discrete Picard condition is used to jointly select the SVD truncation and Tikhonov regularization parameters. We evaluate the performance of the proposed method on both simulated and real NMR measurements.

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A method to predict heterogeneous glutenite reservoir permeability from nuclear magnetic resonance (NMR) logging

Arabian Journal of Geosciences ◽

10.1007/s12517-021-06840-x ◽

2021 ◽

Vol 14 (6) ◽

Author(s):

Zeliang Liang ◽

Zhiguo Cheng ◽

Xuemei Dong ◽

Tingting Hu ◽

Tuo Pan ◽

...

Keyword(s):

Nuclear Magnetic Resonance ◽

Magnetic Resonance ◽

Nmr Logging ◽

Reservoir Permeability ◽

Nuclear Magnetic

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Textural and pore size analysis of carbonates from integrated core and nuclear magnetic resonance logging: An Arbuckle study

Interpretation ◽

10.1190/int-2014-0050.1 ◽

2015 ◽

Vol 3 (1) ◽

pp. SA77-SA89 ◽

Cited By ~ 8

Author(s):

John Doveton ◽

Lynn Watney

Keyword(s):

Nuclear Magnetic Resonance ◽

Relaxation Time ◽

Magnetic Resonance ◽

Pore Size ◽

Relaxation Times ◽

T2 Relaxation Time ◽

T2 Relaxation ◽

Nmr Logging ◽

The Core ◽

Nuclear Magnetic

The T2 relaxation times recorded by nuclear magnetic resonance (NMR) logging are measures of the ratio of the internal surface area to volume of the formation pore system. Although standard porosity logs are restricted to estimating the volume, the NMR log partitions the pore space as a spectrum of pore sizes. These logs have great potential to elucidate carbonate sequences, which can have single, double, or triple porosity systems and whose pores have a wide variety of sizes and shapes. Continuous coring and NMR logging was made of the Cambro-Ordovician Arbuckle saline aquifer in a proposed CO2 injection well in southern Kansas. The large data set gave a rare opportunity to compare the core textural descriptions to NMR T2 relaxation time signatures over an extensive interval. Geochemical logs provided useful elemental information to assess the potential role of paramagnetic components that affect surface relaxivity. Principal component analysis of the T2 relaxation time subdivided the spectrum into five distinctive pore-size classes. When the T2 distribution was allocated between grainstones, packstones, and mudstones, the interparticle porosity component of the spectrum takes a bimodal form that marks a distinction between grain-supported and mud-supported texture. This discrimination was also reflected by the computed gamma-ray log, which recorded contributions from potassium and thorium and therefore assessed clay content reflected by fast relaxation times. A megaporosity class was equated with T2 relaxation times summed from 1024 to 2048 ms bins, and the volumetric curve compared favorably with variation over a range of vug sizes observed in the core. The complementary link between grain textures and pore textures was fruitful in the development of geomodels that integrates geologic core observations with petrophysical log measurements.

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