Wednesday, 4 November 2015

Applications in Geoscience

            CT
Paper: Applications of X-ray computed tomography in the geosciences
“Abstract: X-ray computed tomography (CT) is a non-destructive technique with wide applications in various geological disciplines. It reveals the internal structure of objects, determined by variations in density and atomic composition. Large numbers of parallel 2D sections can be obtained, which allows 3D imaging of selected features. Important applications are the study of porosity and fluid flow, applied to investigations in the fields of petroleum geology, rock mechanics and soil science. Expected future developments include the combined use of CT systems with different resolutions, the wider use of related X-ray techniques and the integration of CT data with results of compatible non-destructive techniques.”

Webpage: http://www.geochemsoc.org/publications/geochemicalnews/gn132jul07/computedtomographyappliedt/

            PET and CT

Paper: Combined positron emission tomography and computed tomography to visualize and quantify fluid flow in sedimentary rocks

“Abstract: Here we show for the first time the combined positron emission tomography (PET) and computed tomography (CT) imaging of flow processes within porous rocks to quantify the development in local fluid saturations. The coupling between local rock structure and displacement fronts is demonstrated in exploratory experiments using this novel approach. We also compare quantification of 3-D temporal and spatial water saturations in two similar CO2storage tests in sandstone imaged separately with PET and CT. The applicability of each visualization technique is evaluated for a range of displacement processes, and the favorable implementation of combining PET/CT for laboratory core analysis is discussed. We learn that the signal-to-noise ratio (SNR) is over an order of magnitude higher for PET compared with CT for the studied processes.”

Comparison of PET and CT in Physical Processes in Sandstones
“Abstract: The migration of moisture in cores of porous homogeneous sandstone of Ledian age (Belgian Eocene, Tertiary) is monitored with PET (Positron Emission Tomography) and micro-focus X-ray radiography. In the case of PET, a nuclear medical imaging technique, 55Co-EDTA (Ethylenediamine Tetraacetic acid) and R-18F were used as water-soluble tracers. The X-ray projection method has evolved from the better-known medical technique and allows a fast and accurate determination of the two-dimensional transient moisture content profiles. Results indicate that both techniques can deliver important information concerning physical processes in situ
Source:http://www.researchgate.net/publication/223215827_Comparison_of_Positron_Emission_Tomography_and_X-ray_radiography_for_studies_of_physical_processes_in_sandstone

       PET

Paper: The influence of deformation bands upon fluid flow using profile permeametry and positron emission tomography

“Abstract: Cataclastic deformation bands are significant discontinuities in sandstone reservoirs since they have dramatically reduced porosity and permeability relative to their host rock, despite their mm-scale displacements. Consequently, these discontinuities often have a large impact upon the flow of fluids at both micro and macro-scales. The effect of this impact in highly porous sandstone has been analyzed using a range of novel and conventional techniques, including pressure decay profile permeametry (PDPK) and positron emission tomography (PET)......  PET was used to monitor fluid flow as a function of pore volume of a sandstone plug containing deformation bands, demonstrating the direct effect of deformation bands as a potential barrier to fluid flow. The results of this study provide a detailed characterization of deformation bands at high resolution, which can be included in advanced reservoir simulation models.

Staßfurt: fluid transport in rock salt - spatial distribution and dynamics




     MRI

Paper: Magnetic resonance sounding: new method for ground water assessment.

“Abstract: The advantage of magnetic resonance sounding (MRS) as compared to other classical geophysical methods is in its water selective approach and reduced ambiguity in determination of subsurface free water content and hydraulic properties of the media due to the nuclear magnetic resonance (NMR) principle applied……”
Source: http://www.ncbi.nlm.nih.gov/pubmed/15035592

 



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