Relaxation and relaxation exchange NMR to characterise asphaltene adsorption and wettability dynamics in siliceous systems

Shikhov, Igor; Li, Rupeng; Arns, Christoph H.

doi:10.1016/j.fuel.2018.02.059

Cited by 33 publications

(46 citation statements)

References 51 publications

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“…NMR and MRI have been widely employed to measure a range of transport properties of various fluids in porous media including various hydrocarbons in rock cores (e.g. Mitchell et al 2013;Coates et al 1999;Zhao et al 2016;Ramskill 2018;Li et al 2016;Li et al 2017a, b;Mitchell et al 2018;Shikhov et al 2018). Whilst these have predominately focused on liquid phase measurements, due predominately to signal-tonoise (SNR) considerations, gas phase NMR/MRI has been used; for example by Zecca et al (2018), to determine the restricted diffusion coefficient of ethane in sandstone cores and, hence, their tortuosity.…”

Section: Introductionmentioning

confidence: 99%

In Situ CH4–CO2 Dispersion Measurements in Rock Cores

Vogt

May

et al. 2019

Transp Porous Med

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Section: Introductionmentioning

confidence: 99%

In Situ CH4–CO2 Dispersion Measurements in Rock Cores

Vogt

May

et al. 2019

Transp Porous Med

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“…The transverse relaxation time is related to the specific surface area of the pores. Specifically, the transverse relaxation increases with the enlargement of the specific surface areas of pores . It can be described using the following equation where T 2 is the transverse relaxation time in ms, S is the specific surface area of the pore in nm 2 , V is the specific volume of the pore in nm 3 , ρ 2 is the transverse surface relaxation coefficient in nm/ms, r is the pore radius in nm, and F s represents the geometry factor.…”

Section: Methodsmentioning

confidence: 99%

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

Cheng

2020

Energy Fuels

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Accurate characterization of the compressibility of pores and fractures in coal reservoirs is of great significance for predicting permeability and for optimizing the production of coalbed methane (CBM). However, for low-rank coal (R o,max < 0.65%), compressibility and the influences of different pore structures and minerals on compressibility have not been studied thoroughly. To solve this problem, four low-rank coal samples were collected from the south of Junggar Basin. Low-field nuclear magnetic resonance is used to study the compressibility of pore and fracture in low-rank coal and its relationship with the heterogeneity. In addition, the effects of fracture structure and minerals on compressibility were studied by combining with micro-CT. The results show that the effects on the compression space of the low-rank coal with the increase in effective stress mainly come from the fracture and seepage pore volume, and the compressibility becomes weaker. The low-rank coal reservoirs with well-developed fractures and seepage pores show better compressibility. The compressibility of the pores and fractures in low-rank coal is noticeably affected by the mineral content, mineral shape, and mineral arrangement. When the fracture development is similar, the coal reservoirs with a high mineral content and with many fractures filled by minerals show poor compressibility. There is a negative linear correlation of the compressibility of pores and fractures with the fractal dimension of the seepage space in low-rank coal. Moreover, the closing rate of the pores and microfractures in low-rank coal with significant heterogeneity in the seepage space is faster under confining pressure. The research results are beneficial to the optimization of CBM production measures in low-rank coal reservoirs.

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“…The latter suggests that dynamic changes in surface properties, e.g. as result of wettability alteration (Shikhov et al 2018(Shikhov et al , 2019, may be understood spatially resolved and inform modelling of two-phase flow (Wang et al 2018a). For such an approach, it would be desirable to replace effective clay parameters with clay structure and surface properties.…”

Section: Introductionmentioning

confidence: 99%

NMR Relaxation Modelling in Porous Media with Dual-Scale-Resolved Internal Magnetic Fields

2022

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A pore-scale forward modelling approach for NMR relaxation responses of sandstones incorporating their dual-scale nature is presented. The approach utilises X-ray micro-CT images to capture inter-granular porosity and scanning electron microscopy images to reconstruct clay regions via a resolved clay micro-structure model. A key to calculating the NMR response with resolved clay micro-structure is the development of a dual-scale internal magnetic field calculation. This is achieved by a separation of near- and far-field effects in a dipole approximation of the internal field with periodic clay micro-structures, the latter of which take local clay pocket porosity into account. Tri-linear interpolation of the micro-CT image before calculation of the internal magnetic field further reduces errors in the transition regions between coarse- and fine-scale structure, with final discretisation level matching the fine-scale clay micro-structure model across the whole domain. The method is validated against direct calculations of model media at full resolution and applied to Bentheimer sandstone. Measured and simulated NMR $$T_2$$ T 2 relaxation responses, including relaxation time distribution shape, are in excellent agreement and distributions of internal magnetic field gradients at the highest spatial resolution as well as diffusion-averaged effective gradients are reported.

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Relaxation and relaxation exchange NMR to characterise asphaltene adsorption and wettability dynamics in siliceous systems

Cited by 33 publications

References 51 publications

In Situ CH4–CO2 Dispersion Measurements in Rock Cores

In Situ CH4–CO2 Dispersion Measurements in Rock Cores

Compressibility of Different Pore and Fracture Structures and Its Relationship with Heterogeneity and Minerals in Low-Rank Coal Reservoirs: An Experimental Study Based on Nuclear Magnetic Resonance and Micro-CT

NMR Relaxation Modelling in Porous Media with Dual-Scale-Resolved Internal Magnetic Fields

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