Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method

Yao, Yanbin; Liu, Dameng; Xie, Songbin

doi:10.1016/j.coal.2014.06.001

Cited by 180 publications

(128 citation statements)

References 18 publications

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“…The noise in CPMG train is assumed to be addictive white Gaussian with zero-mean in most relevant references. Accordingly, the histogram is fitted to the expression in (7). Immediately, the noise variance is evaluated by the standard derivation of the noise from fitting parameter .…”

Section: Methodsmentioning

confidence: 99%

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Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Zhou

Wang

et al. 2019

Mathematical Problems in Engineering

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Two-dimensional (2D) NMR relaxometry has been widely used as a powerful new tool for identifying and characterizing molecular dynamics. Various inversion algorithms have been introduced to obtain the versatile relaxation information conveyed by spectra. The inversion procedure is especially challenging because the relevant data are huge in 2D cases and the inversion problem is ill-posed. Here, we propose a new method to process the 2D NMR relaxometry data. Our approach varies from Tikhonov regularization, known previously in CONTIN and Maximum Entropy (MaxEnt) methods, which need additional efforts to compute an appropriate regularization factor. This variety improves Butler–Reeds–Dawson algorithm to optimize the Tikhonov regularization problem and the regularization factor is calculated alongside. The calculation is considerably faster than the mentioned algorithms. The proposed method is compared with some widely used methods on simulated datasets, regarding algorithm efficiency and noise vulnerability. Also, the result of the experimental data is presented to test the practical utility of the proposed algorithm. The results suggest that our approach is efficient and robust. It can meet different application requirements.

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Section: Methodsmentioning

confidence: 99%

“…The overlapped peaks existing in 1D NMR relaxometry can be distinguished easily in a suitable 2D spectrum. Recently, 2D NMR relaxometry has been widely used as a powerful tool for identifying and characterizing molecular dynamics, especially in materials consisting of many complex components [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Zhou

Wang

et al. 2019

Mathematical Problems in Engineering

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“…(3) Represented by nuclear magnetic resonance (NMR), this method is characterized by a wide measuring range from nano‐ to micron‐scale pores. However, the PSD curves based on T 2 spectrum exhibit high smoothness and single peaks of adsorption pores, seepage pores, and fractures, separately, which shows the data with poor accuracy …”

Section: Introductionmentioning

confidence: 99%

“…However, the PSD curves based on T 2 spectrum exhibit high smoothness and single peaks of adsorption pores, seepage pores, and fractures, separately, which shows the data with poor accuracy. [24][25][26] Nanopores, including micropores (2-10 nm in diameter), transition pores (10-100 nm in diameter), and mesopores (100-1000 nm in diameter), with relatively small pore sizes and large specific surface areas are the main storage space of CBM. These occupy up to 90% of the total amount according to results.…”

mentioning

confidence: 99%

Methane adsorption constrained by pore structure in high‐rank coals using FESEM, CO₂ adsorption, and NMRC techniques

Liu

Cai

Zhou

2019

Energy Science & Engineering

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To evaluate the impacts of nanopores of high‐rank coals on coalbed methane adsorption and storage, 12 anthracite and semianthracite coal samples from Yangquan and Shouyang blocks in the Qinshui Basin were investigated. Field emission scanning electron microscopy (FESEM) and CO2 adsorption combined with nuclear magnetic resonance cryoporometry (NMRC) experiments were used to evaluate the pore structure with diameters ranging from 0 to 500 nm and their impact on adsorption capacity based on qualitative and quantitative analysis. The results show that a coalification jump from semianthracite to anthracite occurred in the study area due to the magmatic intrusion. In the process, the volume of supermicropores and micropores largely increased while the volume of transition pores and mesopores decreased slightly. Additionally, vitrinite gets purified and enriched during the rapid maturation of coal reservoir, which is beneficial to the microporous structure development. The pore size distribution (PSD) of anthracite is mainly divided into two types, which are in serrated and decreasing forms, respectively. Higher vitrinite content can promote the formation of decreasing type (type II), which corresponds to a lower degree of complexity. The fractal dimensions indicate that the heterogeneity of coal samples is increasing with the decrease in pore size. Accordingly, the increase in pore heterogeneity corresponds to the lower adsorption capacity. The main pore sizes that contribute to CBM adsorption include two parts: 25‐30 nm and 50‐60 nm. For the supermicropores with large specific surface areas, the pore system detected by CO2 molecules is not conducive to CBM adsorption, while the increase in pore volume can improve the adsorption rate and capacity of CO2. These findings are vital for a precisely understanding of nanoscale pores as well as future CBM exploitation.

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“…develop an NMR-derived permeability model by explore the relationship of the coal permeability with the moisture migration characteristics [16]. Based on the NMR technology, the method for characterizing the methane adsorption capacity of coals is developed [17].…”

Section: Coals Text Based Nmrmentioning

confidence: 99%

The Feasibility of Low Field NMR Technology in Geotechnical Engineering

Kong

Zhuang

et al. 2018

IOP Conf. Ser.: Earth Environ. Sci.

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Abstract. In resent years, the nuclear magnetic resonance (NMR) technique has been applicated in a relatively small scale, which includes soil, rocks, coals ,concrete and so on. In this paper, the auther indicate the theoretical background of NMR in short words and explain the measurement methods of T 1 and T 2 relaxation. Then the important parameters that have great impact of the result is emphasized. After introducing the representative research scope in soil, rocks, coals and concrete, the advantages and limitation of the NMR application are clear. Although the result of the NMR test is not accurate totally, the trend is correct and the accuracy is trusted in geotechnical engineering.

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Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method

Cited by 180 publications

References 18 publications

Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Methane adsorption constrained by pore structure in high‐rank coals using FESEM, CO₂ adsorption, and NMRC techniques

The Feasibility of Low Field NMR Technology in Geotechnical Engineering

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Quantitative characterization of methane adsorption on coal using a low-field NMR relaxation method

Cited by 180 publications

References 18 publications

Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Improved Butler–Reeds–Dawson Algorithm for the Inversion of Two‐Dimensional NMR Relaxometry Data

Methane adsorption constrained by pore structure in high‐rank coals using FESEM, CO2 adsorption, and NMRC techniques

The Feasibility of Low Field NMR Technology in Geotechnical Engineering

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Methane adsorption constrained by pore structure in high‐rank coals using FESEM, CO₂ adsorption, and NMRC techniques