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Prospects and Challenges for the Spatial Quantification of the Diffusion of Fluids Containing 1H in the Pore System of Rock Cores
- Source :
- Journal of Geophysical Research - Solid Earth; March 2022, Vol. 127 Issue: 3
- Publication Year :
- 2022
-
Abstract
- Nuclear magnetic resonance (MR) (NMR) is commonly used for the determination of rock porosity, as well as pore size distribution (PSD) and tortuosity, required to handle hydrocarbon exploitation. Emerging technologies for NMR equipment now enable the visualization of porosity using magnetic resonance imaging (MRI). Currently, single‐point imaging is the most common MRI technique employed, but diffusion‐weighted imaging has been attracting the attention of geologists and geophysicists. In this study, a more advanced technique, diffusion tensor imaging (DTI), is proposed for the characterization of rock core samples. The main purpose of this paper is to demonstrate the usefulness of DTI in the petrophysical characterization of rocks and discuss its strengths. As an example, a carbonate core sample was examined using DTI. The diffusion tensor (DT) was obtained and DT parameters (mean diffusivity, MD; fractional anisotropy, FA; three eigenvalues; DT components; and proton density, PD) were visualized in 2D and 3D. Each parameter was described and its utility in terms of pore space characterization was analyzed. In addition, a new parameter, principal diffusion tracts, was introduced based on the DT tractography performed in the study. The analysis is summarized in a set of DT parameters and a resultant ellipsoid that delivers complementary information about the sample's pore network microgeometry, including referential measurements of anisotropic phantoms. The applications of DTI for the determination of pore size distribution, tortuosity and conductivity are also shown. The study ends with a consideration of the potential prospects and challenges for DTI‐based examination of rock core samples. An advanced nuclear magnetic resonance technique, diffusion tensor imaging (DTI), is proposed here for the characterization of rock core samples. As an example, a carbonate core sample was subjected to DTI examination, from which the diffusion tensor (DT) was obtained and DT parameters (mean diffusivity, MD; fractional anisotropy, FA; three eigenvalues; DT components and proton density, PD) were visualized in 2D and 3D. Potential examples of the practical applications of the data obtained from the DTI experiment are demonstrated. Importantly, we can now provide spatial and quantitative data which is closely related to the studied microstructure using DTI. The application of DTI for the determination of pore size distribution, tortuosity and conductivity are also shown. The study ends with a consideration of the potential prospects and challenges for the DTI‐based examination of rock core samples. Diffusion tensor imaging enables, rotationally invariant, 3D spatial quantification of diffusion in rocks, reflecting porosity featuresPrincipal diffusion tracts may reflect permeability anisotropy and correspond to the conductivity tensorDTI ellipsoid delivers a set of parameters describing the microgeometry of average or spatially resolved pores Diffusion tensor imaging enables, rotationally invariant, 3D spatial quantification of diffusion in rocks, reflecting porosity features Principal diffusion tracts may reflect permeability anisotropy and correspond to the conductivity tensor DTI ellipsoid delivers a set of parameters describing the microgeometry of average or spatially resolved pores
Details
- Language :
- English
- ISSN :
- 21699313 and 21699356
- Volume :
- 127
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Journal of Geophysical Research - Solid Earth
- Publication Type :
- Periodical
- Accession number :
- ejs59282830
- Full Text :
- https://doi.org/10.1029/2021JB023299