NMR determination of porous media property distributions

Watson, A. T.; Hollenshead, Jeromy T.; Uh, Jinsoo; Chang, C.T.Philip

doi:10.1016/s0066-4103(02)48005-2

Cited by 11 publications

(11 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We use a PFG stimulated-echo technique (Watson et al 2002). A remarkable feature of the stimulated echo, as opposed to the spin echo, is that spins display longitudinal relaxation between the last two RF pulses, which is longer than that of transverse relaxation.…”

Section: Experimental Measurementsmentioning

confidence: 99%

“…We use a Carr-Purcell-Meiboom-Gill (CPMG) imaging pulse sequence with spatial encodings (Watson et al 2002), shown in Fig. 3, to determine the porosity distribution.…”

Section: Porosity Distributionsmentioning

confidence: 99%

“…The CPMG sequence provides for the measurement of the signal intensity at a sequence of times. Using data from each voxel, we solve an associated inverse problem to determine its distribution of relaxation rates (Watson et al 2002). Extrapolation to zero time provides the estimate of the intrinsic intensity.…”

Section: Porosity Distributionsmentioning

confidence: 99%

“…Non-invasive methods to determine the amount of saturating fluid within regions of the sample can provide information about the porosity distributions. X-ray CT scanning (Withjack 1988) and MRI methods (Watson et al 2002) have been reported for this purpose. The determination of the permeability is not so straight-forward since permeability is defined by the Darcy equation (see Eq.…”

Section: Inverse Problem In Conventional Experimentsmentioning

confidence: 99%

See 3 more Smart Citations

Determining Spatial Distributions of Permeability

Watson

2010

Transp Porous Med

Self Cite

View full text Add to dashboard Cite

Conventional laboratory experimentation provides an apparent value of hydraulic permeability which, at best, is representative of the entire sample. Nuclear magnetic resonance imaging (MRI) provides unique opportunities to probe spatial distributions of permeability at a much finer scale (Seto et al., Transp Porous Media 42:351-388, 2001). We advance the methodology for determining spatial distributions of permeability and provide, for the first time, laboratory determinations of permeability distributions with complete threedimensional (3D) spatial resolution. We investigate new experimental designs that mitigate a possible lack of identifiability and provide for more accurate estimates of permeability. We demonstrate the application of MRI experiments and analyses that provide substantial improvements in the determination of the porosity distribution, an essential step for obtaining reliable measurements of spatially resolved velocity distributions. We investigate the use of global optimization to solve the associated inverse problem for determining permeability distributions from the measured velocity distributions. Our methodology is demonstrated with experimental data on sandstone and trabecular bone samples.Keywords Hydraulic permeability · Nuclear magnetic resonance imaging · Inverse problem Nomenclature A c Cross-sectional area B m i ith B-spline basis function with the order of m

show abstract

Section: Experimental Measurementsmentioning

confidence: 99%

“…We use a Carr-Purcell-Meiboom-Gill (CPMG) imaging pulse sequence with spatial encodings (Watson et al 2002), shown in Fig. 3, to determine the porosity distribution.…”

Section: Porosity Distributionsmentioning

confidence: 99%

Section: Porosity Distributionsmentioning

confidence: 99%

Section: Inverse Problem In Conventional Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Determining Spatial Distributions of Permeability

Watson

2010

Transp Porous Med

Self Cite

View full text Add to dashboard Cite

show abstract

“…Experimental and analysis methods have been developed to resolve spatial distributions of fundamental properties for describing flow that are unavailable by any other means. These include porosity (Watson et al 2002;Fantazzini et al 2004;Marica et al 2006), permeability Watson 2011, 2013), fluid saturations (Chen et al 1993;Davies et al 1994;Li et al 2007), and fluid velocities (Chang and Watson 1999). Equipment used to conduct experiments in the field normally employs much smaller magnetic fields and more limited radio-frequency controls, and they lack the means to pulse magnetic-field gradients.…”

Section: Introductionmentioning

confidence: 99%

A Nonparametric Approach for Determining NMR Relaxation Distributions

Watson

2014

Transp Porous Med

Self Cite

View full text Add to dashboard Cite

Nuclear magnetic resonance (NMR) and imaging (MRI) can provide unique information about fluid distributions, flow, transport properties, and morphology within permeable media. The mathematical description of NMR relaxation of fluids in permeable media is one key element used to develop such information. We introduce and evaluate nonparametric regression theory to determine continuous relaxation distribution functions from NMR/MRI experiments. Unlike other methods, ours is based on determining the best estimate of the distribution function from experimental data. Our method is robust and does not require user interventions, so it is particularly valuable for accurately determining fluid distributions from MRI experiments. Such information is essential for determining porosity, permeability, and fluid saturation distributions, as well as permeable media morphologies.

show abstract

NMR microimaging of fluid flow in model string-type reactors

Koptyug

Kovtunov

Gerkema

et al. 2007

Chemical Engineering Science

View full text Add to dashboard Cite

Magnetic resonance microimaging (MRM) was employed to obtain quantitative velocity maps of water flowing in the channels possessing unconventional cross-section shapes formed by a bundle of parallel fibers within a tubular string-type reactor. The maps obtained demonstrate the presence of large amounts of an almost stagnant liquid in the stretched corners of the cross-sections representing distorted triangles or squares. This fact together with the irregularity of the filaments packing in the model string-type reactor was demonstrated to lead to a broad residence time distributions (RTDs) for liquid flow. Next, the pulsed field gradient NMR (PFG NMR) technique was employed to compare transport of water with that of butane gas in the same model string-type reactor. The experimentally measured average propagators (travel distance probability density functions) have demonstrated that Taylor dispersion can lead to much better RTDs for gas as compared to liquid in channels with sub-millimeter equivalent diameters. The PFG NMR data were compared with the RTD obtained using the conventional tracer time-of-flight transient response method. It is concluded that due to the differences in the quantities actually measured by the two techniques, and the significant differences in the measurement length scales (microns to 1-2 cm for NMR/MRM, tens of centimeters for transient response methods), there is no reliable way of directly comparing these results. The information obtained by NMR/MRM and more conventional techniques such as time-of-flight should be considered as complementary. In particular, NMR/MRM can reveal the reasons for the observed overall reactor performance by providing access to the transport processes on short length scales inside the reactor and by revealing structure-transport interrelations. ᭧

show abstract

NMR determination of porous media property distributions

Cited by 11 publications

References 21 publications

Determining Spatial Distributions of Permeability

Determining Spatial Distributions of Permeability

A Nonparametric Approach for Determining NMR Relaxation Distributions

NMR microimaging of fluid flow in model string-type reactors

Contact Info

Product

Resources

About