ZTE MRI in high magnetic field as a time effective 3D imaging technique for monitoring water ingress in porous rocks at sub-millimetre resolution

Węglarz, Władysław P.; Krzyżak, Artur; Machowski, Grzegorz; Stefaniuk, M.

doi:10.1016/j.mri.2017.11.015

Cited by 9 publications

(18 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The bright spots in the images of core plug BM and F were a result of vugs originating from dissolution-and fracture-related porosity. More advanced MRI sequences with shorter echo times should be used to image tight rocks with paramagnetic impurities, such as UTE (ultrashort echo time) and ZTE (zero echo time) imaging [26,27]. core plug that gave the best image was sample D, followed by sample BM.…”

Section: Nmr/mri Characterizationmentioning

confidence: 99%

Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

et al. 2020

View full text Add to dashboard Cite

In this paper, we investigate the effect of magnetic field strength on the transverse relaxation time constant (T2) in six distinct core plugs from four different rock types (three sandstones, one basalt, one volcanic tuff and one siltstone), retrieved from offshore Ireland. The CPMG pulse-sequence was used at two different magnetic field strengths: high-field at 4.70 T and low-field at 0.28 T. Axial images of the core plugs were also acquired with the RAREst sequence at high magnetic field strength. Thin-sections of the core plugs were prepared for optical imaging and SEM analysis, and provided qualitative information on the porosity and quantification of the elemental composition of the rock material. The content of iron varied from 4 wt. % to close to zero in the rock samples. Nevertheless, the effective T2 distributions obtained at low-field were used to successfully predict the porosity of the core plugs. Severe signal attenuations from internal magnetic gradients resulted in an underestimation of the porosity at high-field. No definitive trend was identified on the evolution of discrete relaxation time components between magnetic field strengths. The low-field measurements demonstrate that NMR is a powerful quantitative tool for petrophysical rock analysis as compared to thin-section analysis. The results of this study are of interest to the research community who characterizes natural gas hydrates in tight heterogeneous core plugs, and who typically relies on MR imaging to distinguish between solid hydrates and fluid phases. It further exemplifies the importance of selecting appropriate magnetic field strengths when employing NMR/MRI for porosity calculation in tight rock.

show abstract

Section: Nmr/mri Characterizationmentioning

confidence: 99%

Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

et al. 2020

View full text Add to dashboard Cite

show abstract

“…Some NMR methods are not new to geological media characterization, but NMR's evolving versatility offers significant advantages. For instance, time‐domain NMR (TD‐NMR) data can be collected at low‐field strength (0.05 T) 1,3,4 . With this low field, the induced internal gradients that compromise NMR signals at higher field strength are minimized.…”

Section: Introductionmentioning

confidence: 99%

“…Zero Echo Time (ZTE) is a pulse sequence that has been used for image collection of a variety of porous media. This pulse sequence uses a smaller excitation flip angle (5°), constant gradients and radial k ‐space encoding techniques 1,3,4,8‐10 . When compared to the more common pulse sequences that use 90°‐flip angles, the 5°‐flip angle used in ZTE allows for a much shorter pulse time, leading to less relaxation of the magnetization before the receiver is switched on.…”

Section: Introductionmentioning

confidence: 99%

“…This technique has been used in multiple fields such as imaging tissues with T 2 value on the μs scale in animal bones and human teeth 2,9,10 . The ZTE pulse sequence has also been applied to image porous media such as dolomite, reef reservoirs and sandstone 1,3,4,10 …”

Section: Introductionmentioning

confidence: 99%

“…To assist this process, we combined image analysis and processing with PCA to analyze pore‐space connectivity. The resulting workflow was tested on artificial and natural porous media such as glass‐bead packs, sandstone and carbonate lithologies exhibiting a variety of pore distributions 1,3,4,16 . We began by using a porous medium consisting of 4‐mm borosilicate glass beads submerged in water.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Analysis of ZTE MRI application to sandstone and carbonate

et al. 2020

View full text Add to dashboard Cite

Microtomography (μCT) and nuclear magnetic resonance (NMR) have been used to characterize porous media for decades. Magnetic resonance imaging (MRI) enables direct visualization of pore architecture and many pulse sequences exist. In this work, we tested the MRI pulse sequence Zero Echo Time (ZTE) to study sandstone and carbonate for its ability to address short relaxation times. We aimed at resolving two fluid conduit scales, that is, pores and fractures. In this research, we study tighter porous systems than those previously reported using ZTE. Additionally, pore cluster analysis (PCA), combined with ZTE, can be used to analyze pore‐fracture connectivity of relatively large core plugs. We show that ZTE can resolve two‐scale pore systems simultaneously, that is, fractures and pores. By combining time‐domain NMR pore‐size analysis and PCA, we show that careful selection of resolution is necessary to understand transport in porous media.

show abstract

Liquid saturation evaluation in organic-rich unconventional reservoirs: A comprehensive review

Nikolaev

Kazak

2019

Earth-Science Reviews

View full text Add to dashboard Cite

ZTE MRI in high magnetic field as a time effective 3D imaging technique for monitoring water ingress in porous rocks at sub-millimetre resolution

Cited by 9 publications

References 18 publications

Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

Effect of Mineral Composition on Transverse Relaxation Time Distributions and MR Imaging of Tight Rocks from Offshore Ireland

Analysis of ZTE MRI application to sandstone and carbonate

Liquid saturation evaluation in organic-rich unconventional reservoirs: A comprehensive review

Contact Info

Product

Resources

About