A new application of NMR in characterization of multiphase methane and adsorption capacity of shale

Yao, Yanbin; Li, Jun; Liu, Dameng; Chen, Jiyu; Pan, Zhejun

doi:10.1016/j.coal.2018.11.018

Cited by 102 publications

(111 citation statements)

References 18 publications

Supporting

Mentioning

107

Contrasting

Order By: Relevance

“…As shown in Figure 2, there are three distinct peaks for the samples: the left peak (P1) centered at 0.1-10 ms, the middle peak (P2) at approximately 10-100 ms, and the right peak (P3) at > 100 ms. The configurations of the T 2 spectra distributions represent the pore size distribution, with smaller pores having a shorter relaxation time, and a longer relaxation time for larger pores (Yao et al, 2019). Generally, the P3 peaks represent the bulk water content in the corner and surface of the samples.…”

Section: Resultsmentioning

confidence: 99%

Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

Sun

Qin

et al. 2020

Energy Exploration & Exploitation

View full text Add to dashboard Cite

The hydrate reservoir in the Shenhu Area of the South China Sea is a typical clayey-silt porous media with high clay mineral content and poor cementation, in which gas hydrate formation and dissociation characteristics are unclear. In this study, the CO2 hydrate saturation, growth rate, and permeability were studied in sandstone, artificial samples, and clayey-silt sediments using a custom-built measurement apparatus based on the low-field NMR technique. Results show that the T2 spectra amplitudes decrease with the hydrate formation and increase with the dissociation process. For the artificial samples and Shenhu sediments, the CO2 hydrate occupies larger pores first and the homogeneity of the sandstone pores becomes poor. Meanwhile, compared with the clayey-silt sediments, CO2 hydrate is easier to form and with higher hydrate saturation for the sandstone and artificial samples. In hydrate dissociation process, there exists a protection mechanism, i.e. the dissociation near the center of hydrates grain is suppressed when gas pressure drops suddenly and quickly. For permeability of those samples, it decreased with hydrate forms, and increases with hydrate dissociation. Meanwhile, with the same hydrate saturation, permeability is higher in hydrate formation than in dissociation.

show abstract

Section: Resultsmentioning

confidence: 99%

Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

Sun

Qin

et al. 2020

Energy Exploration & Exploitation

View full text Add to dashboard Cite

show abstract

“…Direct observation methods are, for example, scanning electron microscopy (SEM) [5,6], X-ray computerized tomography (X-CT) [7,8] and atomic force microscope (AFM) [9,10], which can be used 2 of 18 to characterize the two-or three-dimensional distribution of coal PSDs. Indirectly inferred methods include mercury intrusion porosimetry (MIP) [11,12], gas adsorption (N 2 and CO 2 ) [13][14][15][16] and nuclear magnetic resonance (NMR) [17][18][19]. Among of these methods, MIP measurement has been proven as an effective method to estimate the PSD of coals.…”

Section: Introductionmentioning

confidence: 99%

Insights into Multifractal Characterization of Coals by Mercury Intrusion Porosimetry

et al. 2019

Self Cite

View full text Add to dashboard Cite

Mercury intrusion porosimetry (MIP) as a practical and effective measurement has been widely used in characterizing the pore size distribution (PSD) for unconventional reservoirs (e.g., coals and shales). However, in the process of MIP experiments, the high mercury intrusion pressure may cause matrix compressibility and result in inaccurate estimations of PSD. To get a deeper understanding of the variability and heterogeneity characteristics of the actual PSD in coals, this study firstly corrected the high mercury intrusion pressure data in combination with low-temperature N 2 adsorption (LTNA) data. The results show that the matrix compressibility was obvious under the pressure over 24.75 MPa, and the calculated matrix compressibility coefficients of bituminous and anthracite coals range from 0.82 to 2.47 × 10 −10 m 2 /N. Then, multifractal analysis was introduced to evaluate the heterogeneity characteristics of coals based on the corrected MIP data. The multifractal dimension D min is positively correlated with vitrinite content, but negatively correlated with inertinite content and mercury intrusion saturation. The multifractal dimension D max shows negative relationships with moisture and ash content, and it also emerges as a "U-shaped" trend with efficiency of mercury withdrawal. It is concluded that multifractal analysis can be served as a practical method not only for evaluating the heterogeneity of coal PSDs, but also for other unconventional reservoirs (e.g., shale and tight sandstone).

show abstract

“…The deviations between their method and traditional volumetric method are in range of 0.50%-11.09%. Then, Yao et al [50] improved the low-field NMR method by taking a factor "pipeline volume" into consideration and applied it to calculate the adsorbed methane volume in two shale samples. The calculated adsorbed methane volumes fit well with values from the gravimetric method.…”

Section: Introductionmentioning

confidence: 99%

“…As an organic rock, the pore property (i.e., types, structure, and pore size distribution) of coal is different to that of shale rock which would influence the gas adsorption performance in reservoirs. However, to the best of the authors' knowledge, the suitability of this modified low-field NMR method [50] on a coal sample and the influence of the coal rank on the results from this method have never been discussed. In this study,…”

Section: Introductionmentioning

confidence: 99%

Application of a Modified Low-Field NMR Method on Methane Adsorption of Medium-Rank Coals

et al. 2021

View full text Add to dashboard Cite

Methane adsorption capacity is an important parameter for coalbed methane (CBM) exploitation and development. Traditional examination methods are mostly time-consuming and could not detect the dynamic processes of adsorption. In this study, a modified low-field nuclear magnetic resonance (NMR) method that compensates for these shortcomings was used to quantitatively examine the methane adsorption capacity of seven medium-rank coals. Based on the typical T 2 amplitudes obtained from low-field NMR measurement, the volume of adsorbed methane was calculated. The results indicate that the Langmuir volume of seven samples is in a range of 18.9–31.85 m3/t which increases as the coal rank increases. The pore size in range 1-10 nm is the main contributor for gas adsorption in these medium-rank coal samples. Comparing the adsorption isotherms of these coal samples from the modified low-field NMR method and volumetric method, the absolute deviations between these two methods are less than 1.03 m3/t while the relative deviations fall within 4.76%. The absolute deviations and relative deviations decrease as vitrinite reflectance ( R o ) increases from 1.08% to 1.80%. These results show that the modified low-field NMR method is credible to measure the methane adsorption capacity and the precision of this method may be influenced by coal rank.

show abstract

A new application of NMR in characterization of multiphase methane and adsorption capacity of shale

Cited by 102 publications

References 18 publications

Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

Gas hydrate in-situ formation and dissociation in clayey-silt sediments: An investigation by low-field NMR

Insights into Multifractal Characterization of Coals by Mercury Intrusion Porosimetry

Application of a Modified Low-Field NMR Method on Methane Adsorption of Medium-Rank Coals

Contact Info

Product

Resources

About