Nuclear magnetic resonance surface relaxivity and its advanced application in calculating pore size distributions

Zhao, Peiqiang; Wang, Liang; Xu, Chenhao; Fu, Jinhua; Shi, Yuqing; Mao, Zhiqiang; Xiao, Dianshi

doi:10.1016/j.marpetgeo.2019.08.002

Cited by 30 publications

(19 citation statements)

References 30 publications

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“…where the factor S/V is the pore surface-to-volume ratio. These relaxation times can be used to gain useful information about the porous matrix [83,[91][92][93][94]97] and possible changes over time when subjected to different environmental factors.…”

Section: Nmr Relaxationmentioning

confidence: 99%

“…When atoms diffuse through a porous matrix they will encounter the pore surface, where relaxation due to dipoles or other effects occurs. How effectively this surface relaxation occurs depends on the particular medium and is quantified by the surface relaxivity

[m/s] [ 91 , 92 , 93 , 94 , 95 ]. Depending on the diffusion constant ( D [m

/s]), pore radius ( r [m]) and surface relaxation, different regimes can be excluded [ 96 ].…”

Section: Theorymentioning

confidence: 99%

“…In the fast diffusion regime, Brownstein and Tarr found that

and

can be approximated by

where the factor

is the pore surface-to-volume ratio. These relaxation times can be used to gain useful information about the porous matrix [ 83 , 91 , 92 , 93 , 94 , 97 ] and possible changes over time when subjected to different environmental factors.…”

Section: Theorymentioning

confidence: 99%

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NMR Profiling of Reaction and Transport in Thin Layers: A Review

et al. 2022

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Reaction and transport processes in thin layers of between 10 and 1000 µm are important factors in determining their performance, stability and degradation. In this review, we discuss the potential of high-gradient Nuclear Magnetic Resonance (NMR) as a tool to study both reactions and transport in these layers spatially and temporally resolved. As the NMR resolution depends on gradient strength, the high spatial resolution required in submillimeter layers can only be achieved with specially designed high-gradient setups. Three different high-gradient setups exist: STRAFI (STRay FIeld), GARField (Gradient-At-Right-angles-to-Field) and MOUSE (MObile Universal Surface Explorer). The aim of this review is to provide a detailed overview of the three techniques and their ability to visualize reactions and transport processes using physical observable properties such as hydrogen density, diffusion, T1- and T2-relaxation. Finally, different examples from literature will be presented to illustrate the wide variety of applications that can be studied and the corresponding value of the techniques.

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Section: Nmr Relaxationmentioning

confidence: 99%

[m/s] [ 91 , 92 , 93 , 94 , 95 ]. Depending on the diffusion constant ( D [m

/s]), pore radius ( r [m]) and surface relaxation, different regimes can be excluded [ 96 ].…”

Section: Theorymentioning

confidence: 99%

“…In the fast diffusion regime, Brownstein and Tarr found that

and

can be approximated by

where the factor

Section: Theorymentioning

confidence: 99%

See 1 more Smart Citation

NMR Profiling of Reaction and Transport in Thin Layers: A Review

et al. 2022

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“…On an assumption that a linear relationship exists between T 2 and the pore size distribution, the conversion coefficients of the NMR pore size distribution T 2 spectrum and the pore radius were calculated. Then, the NMR T 2 distribution was converted to the NMR capillary force curve, during which the value of the conversion coefficient (C 0 ) ranges from 33.3 to 250 [28][29][30]. As for the double-peak T 2 spectrum, two capillary pressure curves were separately constructed on both micropore and macropore segments by using two different power functions, and the linear method and power function method were used to construct the capillary pressure curve separately [31].…”

Section: Introductionmentioning

confidence: 99%

NMR Analysis Method of Gas Flow Pattern in the Process of Shale Gas Depletion Development

Shen

Duan

et al. 2022

Geofluids

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Shale gas reservoirs have pores of various sizes, in which gas flows in different patterns. The coexistence of multiple gas flow patterns is common. In order to quantitatively characterize the flow pattern in the process of shale gas depletion development, a physical simulation experiment of shale gas depletion development was designed, and a high-pressure on-line NMR analysis method of gas flow pattern in this process was proposed. The signal amplitudes of methane in pores of various sizes at different pressure levels were calculated according to the conversion relationship between the NMR T 2 relaxation time and pore radius, and then, the flow patterns of methane in pores of various sizes under different pore pressure conditions were analyzed as per the flow pattern determination criteria. It is found that there are three flow patterns in the process of shale gas depletion development, i.e., continuous medium flow, slip flow, and transitional flow, which account for 73.5%, 25.8%, and 0.7% of total gas flow, respectively. When the pore pressure is high, the continuous medium flow is dominant. With the gas production in shale reservoir, the pore pressure decreases, the Knudsen number increases, and the pore size range of slip flow zone and transitional flow zone expands. When the reservoir pressure is higher than the critical desorption pressure, the adsorbed gas is not desorbed intensively, and the produced gas is mainly free gas. When the reservoir pressure is lower than the critical desorption pressure, the adsorbed gas is gradually desorbed, and the proportion of desorbed gas in the produced gas gradually increases.

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“…Edited by Jie Hao and Xiu-Qiu Peng shale oil resources in the Yanchang Formation of the Ordos Basin, China (Er et al 2016;Yin et al 2020). At present, there are several experimental methods for characterizing shale and tight sandstone pore structures, including thin section analysis, scanning electron microscopy (SEM), high-pressure mercury intrusion (HPMI) (Lai et al 2018;Wang et al 2019), N 2 GA (Chen et al 2017;Li et al 2019;Singh 2016;Singh and Cai 2018), NMR (Shao et al 2017;Zhao et al 2020), micro/nano CT scanning (Peng et al 2011;Yang et al 2019) and so on. In 1980s Mandelbrot proposed the fractal theory and then it has been widely used in many fields (Mandelbrot 1983), and many scholars have studied the characteristics of pore structures in sedimentary rocks combining fractal theory with various experimental methods (Li et al 2017;Wang et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Multifractal characteristics of shale and tight sandstone pore structures with nitrogen adsorption and nuclear magnetic resonance

2020

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Based on the experiments of nitrogen gas adsorption (N2GA) and nuclear magnetic resonance (NMR), the multifractal characteristics of pore structures in shale and tight sandstone from the Chang 7 member of Triassic Yanchang Formation in Ordos Basin, NW China, are investigated. The multifractal spectra obtained from N2GA and NMR are analyzed with pore throat structure parameters. The results show that the pore size distributions obtained from N2GA and NMR are different, and the obtained multifractal characteristics vary from each other. The specific surface and total pore volume obtained by N2GA experiment have correlations with multifractal characteristics. For the core samples with the similar specific surface, the value of the deviation of multifractal spectra Rd increases with the increase in the proportion of large pores. When the proportion of macropores is small, the Rd value will increase with the increase in specific surface. The multifractal characteristics of pore structures are influenced by specific surface area, average pore size and adsorption volume measured from N2GA experiment. The multifractal characteristic parameters of tight sandstone measured from NMR spectra are larger than those of shale, which may be caused by the differences in pore size distribution and porosity of shale and tight sandstone.

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Nuclear magnetic resonance surface relaxivity and its advanced application in calculating pore size distributions

Cited by 30 publications

References 30 publications

NMR Profiling of Reaction and Transport in Thin Layers: A Review

NMR Profiling of Reaction and Transport in Thin Layers: A Review

NMR Analysis Method of Gas Flow Pattern in the Process of Shale Gas Depletion Development

Multifractal characteristics of shale and tight sandstone pore structures with nitrogen adsorption and nuclear magnetic resonance

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