Characterization of fluid distributions in porous media by NMR techniques

Liaw, Hsie‐Keng; Kulkarni, R. N.; Chen, Songhua; Watson, A. T.

doi:10.1002/aic.690420223

“…In recent years, several researchers have studied the relationship between NMR and multiphase flow behavior on the pore scale to better understand and infer the storage and transport properties of partially saturated rocks or sediments (e.g., Chen et al, 1994;Liaw et al, 1996;Ioannidis et al, 2006;Jia et al, 2007;Al-Mahrooqi et al, 2006;Costabel andYaramanci, 2011, 2013;Talabi et al, 2009). As an extension of this research, we study the relationship between the water distribution inside the pores of a partially satuPublished by Copernicus Publications on behalf of the European Geosciences Union.…”

Section: Introductionmentioning

confidence: 96%

Understanding NMR relaxometry of partially water-saturated rocks

Mohnke

¹

,

Jorand

²

,

Nordlund

³

2015

Hydrol. Earth Syst. Sci.

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Abstract. Nuclear magnetic resonance (NMR) relaxometry measurements are commonly used to characterize the storage and transport properties of water-saturated rocks. Estimations of these properties are based on the direct link of the initial NMR signal amplitude to porosity (water content) and of the NMR relaxation time to pore size. Herein, pore shapes are usually assumed to be spherical or cylindrical. However, the NMR response at partial water saturation for natural sediments and rocks may differ strongly from the responses calculated for spherical or cylindrical pores, because these pore shapes do not account for water menisci remaining in the corners of desaturated angular pores. Therefore, we consider a bundle of pores with triangular cross sections. We introduce analytical solutions of the NMR equations at partial saturation of these pores, which account for water menisci of desaturated pores. After developing equations that describe the water distribution inside the pores, we calculate the NMR response at partial saturation for imbibition and drainage based on the deduced water distributions.For this pore model, the NMR amplitudes and NMR relaxation times at partial water saturation strongly depend on pore shape, i.e., arising from the capillary pressure and pore shape-dependent water distribution in desaturated pores with triangular cross sections. Even so, the NMR relaxation time at full saturation only depends on the surface-to-volume ratio of the pore. Moreover, we show the qualitative agreement of the saturation-dependent relaxation-time distributions of our model with those observed for rocks and soils.

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“…We have reported some results of experimental analysis with our approach (Hollenshead et al 2001;Liaw et al 1996). While the method seems to work well with glass beads and some rock samples, the expected linear dependency of time-dependent diffusivity on the square root of diffusion time was not observed for Exxon samples.…”

Section: Introductionmentioning

confidence: 90%

“…Our research has been focused on determining pore-size distributions within porous media using characteristic relaxation times (Chang et al 2000;Liaw et al 1996). We have conducted a series of inversion recovery experiments on core samples and analyzed the data to determine T 1 relaxation distributions.…”

Section: Introductionmentioning

confidence: 99%

NMR Characterizations of Properties of Heterogeneous Media

Uh¹,

Phan²,

Duan³

et al. 2003

Self Cite

0

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The overall goal of this project is to develop reliable methods for resolving macroscopic properties important for describing the flow of one or more fluid phases in reservoirs from formation measurements. In Stage I, we develop advanced core analysis tools to determine macroscopic properties-the porosity, absolute, and relative permeability-within heterogeneous core samples. In Stage II we use these methods, together with additional NMR spectroscopic measurements, to obtain data for development of predictive methods. In Stage III, we develop improved relations for predicting permeabilities, and test a novel method for predicting relative permeability, from NMR well-log observable properties.During this reporting period, the determination of surface relaxivity from NMR data is investigated. A new method for determining the surface relaxivity from measured data is developed and tested with data obtained from an Exxon sample. The new method avoids the use of a certain mathematical short-time approximation in the data analysis, which has been shown to be unsuitable.Numerical work is in progress to simulate two-phase displacement experiments using all three spatial dimensions when estimating two-phase flow functions (relative permeability and capillary pressure properties). The modification of the computer code is underway with tests of the changes with specific examples.ii

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“…If a porous medium is composed of isolated spherical pores which have a size distribution, the fraction of fluid associated with pore-radii within log(a) and log(a) + d log(a) is represented by (Lowell and Shields 1984;Liaw et al 1996), where the pore-size distribution P…”

Section: Stimulated Echo From Spherical Pores With a Size Distributionmentioning

confidence: 99%

NMR Characterizations of Properties of Heterogeneous Media

Watson

¹

,

Phan²,

Uh³

et al. 2003

Self Cite

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The overall goal of this project is to develop reliable methods for resolving macroscopic properties important for describing the flow of one or more fluid phases in reservoirs from formation measurements. In Stage I, we develop advanced core analysis tools to determine macroscopic properties-the porosity, absolute, and relative permeability-within heterogeneous core samples. In Stage II we use these methods, together with additional NMR spectroscopic measurements, to obtain data for development of predictive methods. In Stage III, we develop improved relations for predicting permeabilities, and test a novel method for predicting relative permeability, from NMR well-log observable properties.During this reporting period, the determination of surface relaxivity from NMR data is investigated. A new method for determining the surface relaxivity from measured data is developed and tested with data obtained from an Exxon sample. The new method avoids the use of a certain mathematical short-time approximation in the data analysis, which has been shown to be unsuitable.Numerical work is in progress to simulate two-phase displacement experiments using all three spatial dimensions when estimating two-phase flow functions (relative permeability and capillary pressure properties). The modification of the computer code is underway with tests of the changes with specific examples.ii

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Characterization of fluid distributions in porous media by NMR techniques

Abstract: Nuclear magnetic resonance (NMR)

Cited by 81 publications

References 26 publications

Understanding NMR relaxometry of partially water-saturated rocks

Understanding NMR relaxometry of partially water-saturated rocks

NMR Characterizations of Properties of Heterogeneous Media

NMR Characterizations of Properties of Heterogeneous Media

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