Characterization of sub-seismic resolution structural diagenetic heterogeneities in porous sandstones: Combining ground-penetrating radar profiles with geomechanical and petrophysical in situ measurements (Northern Apennines, Italy)

Accurate characterization of forest litter is of high interest for land surface modeling and for interpreting remote sensing observations over forested areas. Due to the large spatial heterogeneity of forest litter, scattering from litter layers has to be considered when sensed using microwave techniques. Here, we apply a full-waveform radar model combined with a surface roughness model to ultrawideband ground-penetrating radar (GPR) data acquired above forest litter during controlled and in situ experiments. For both experiments, the proposed modeling approach successfully described the radar data, with improvements compared to a previous study in which roughness was not directly accounted for. Inversion of the GPR data also provided reliable estimates of the relative dielectric permittivity of the recently fallen litter (OL layer) and of the fragmented litter in partial decomposition (OF layer) with, respectively, averaged values of 1.35 and 3.8 for the controlled experiment and of 3.9 and 7.5 for the in situ experiment. These results show the promising potentialities of GPR for efficient and non-invasive characterization of forest organic layers.

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Combining Ground-Penetrating Radar profiles with geomechanical and petrophysical in situ measurements to characterize sub-seismic resolution structural and diagenetic heterogeneities in porous sandstones (Northern Apennines, Italy)

10.5194/egusphere-egu2020-3118 ◽

2020 ◽

Author(s):

Leonardo Del Sole ◽

Antonino Calafato ◽

Marco Antonellini

Keyword(s):

Ground Penetrating Radar ◽

Host Rock ◽

Northern Apennines ◽

Reservoir Rock ◽

Small Scale ◽

Strengthening Effect ◽

Deformation Bands ◽

Geomechanical Properties ◽

Seismic Resolution ◽

Ground Penetrating

<p>Deformation bands and structurally-related diagenetic heterogeneities, here named Structural Diagenetic Heterogeneities (SDH), have been recognized to affect subsurface fluid flow on a range of scales and potentially promoting reservoir compartmentalization, altering flow paths, influencing flow buffering, and sealing during production. Their impact on reservoir hydraulic properties depends on many factors, such as their permeability contrast with respect to the undeformed reservoir rock, their anisotropy, thickness, geometry as well as their physical connectivity and arrangement in the subsurface. Deformation bands offsets (from a few mm to 20-40 mm) and diagenetic heterogeneities (carbonate nodules) dimensions (from 0.2 to 15 m in length; from 0.1 to 1.0 m in thickness) make them SDH below seismic resolution.</p><p>We used Ground Penetrating Radar (GPR) for detection and analysis of the assemblage &#8220;deformation bands - carbonate nodules&#8221;, in high-porosity arkose sandstone of the Northern Apennines (Italy). Petrophysical (air-permeability) and mechanical (uniaxial compressive strength) properties of host rock, deformation bands, and calcite-cement nodules were evaluated along a 30-meters thick stratigraphic log to characterize the permeability and strength variations of those features. 2D GPR surveys allowed the description of the SDH spatial organization, geometry, and continuity in the subsurface. The assemblage &#8220;deformation bands &#8211; nodules&#8221; decreases porosity and permeability and produces a strengthening effect of the rock volume, inducing a strong mechanical and petrophysical heterogeneity to the pristine rock. Different textural, petrophysical, and geomechanical properties of deformation bands, nodules, and host rock result in different GPR response (dielectric permittivity; instantaneous attributes). We show that GPR can be useful to characterize variations in petrophysical and geomechanical properties other than characterize the geometry and spatial distribution of flow baffles and small-scale flow barriers in the subsurface such as deformation bands and cement-nodules. GPR showed its worth as a high-resolution and non-invasive tool to extend outcrop information (petrophysical and geomechanical data) to 3D subsurface volumes in a way to reconstruct realistic and detailed outcrop analogues. Such potential could be critical in assisting and improving the characterization of SDH networks in the study of faulted aquifers and reservoirs in porous sandstones.</p>

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An Automatic Processing Framework for In Situ Determination of Ecohydrological Root Water Content by Ground-Penetrating Radar

IEEE Transactions on Geoscience and Remote Sensing ◽

10.1109/tgrs.2021.3065066 ◽

2021 ◽

pp. 1-15

Author(s):

Xinbo Liu ◽

Li Guo ◽

Xihong Cui ◽

John R. Butnor ◽

Elizabeth W. Boyer ◽

...

Keyword(s):

Water Content ◽

Ground Penetrating Radar ◽

Automatic Processing ◽

Ground Penetrating ◽

Processing Framework

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Characterization of tillage effects on the spatial variation of soil properties using ground-penetrating radar and electromagnetic induction

Geoderma ◽

10.1016/j.geoderma.2013.05.024 ◽

2013 ◽

Vol 207-208 ◽

pp. 310-322 ◽

Cited By ~ 29

Author(s):

François Jonard ◽

Mohammad Mahmoudzadeh ◽

Christian Roisin ◽

Lutz Weihermüller ◽

Frédéric André ◽

...

Keyword(s):

Soil Properties ◽

Spatial Variation ◽

Ground Penetrating Radar ◽

Electromagnetic Induction ◽

Ground Penetrating

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Ground-penetrating radar imaging of Albian rudist buildups, central Texas

Interpretation ◽

10.1190/int-2014-0273.1 ◽

2015 ◽

Vol 3 (3) ◽

pp. SY67-SY81 ◽

Cited By ~ 1

Author(s):

Xavier Janson ◽

Keumsuk Lee ◽

Chris Zahm ◽

Charles Kerans

Keyword(s):

Middle East ◽

Ground Penetrating Radar ◽

Reservoir Modeling ◽

Size Difference ◽

Seismic Resolution ◽

Stratigraphic Architecture ◽

Order Of Magnitude ◽

Central Texas ◽

Ground Penetrating ◽

Subsurface Reservoir

Rudist buildups are important reservoirs in many Cretaceous fields in the Middle East, but they are generally near or below seismic resolution. The dimension, shape, and architecture of rudist buildups can be assessed using outcrop, although only partly so because of pseudo-2D observations of geobodies intersecting with the outcrop. We used ground-penetrating radar to enhance our understanding of the shape, dimension, and architecture of Albian rudist buildups in two outcrops in Texas. In the Lake Georgetown spillway, caprinid rudist buildups are 10–30 m wide and 2–7 m high. They are elliptical with an aspect ratio of as much as 1.7. They show no or very little flank development. The older buildup exposed in the Red Bluff Creek area displays 10- to 25-m-wide and 5- to 10-m-high in situ caprinid rudist mound core accumulations with as much as 100-m-wide reworked flanks in the shallower part of the depositional profile. Downdip along the depositional profile, caprinid buildups are 5–20 m wide and 3–7 m high with no flank debris. The buildups in the Lake Georgetown area have similar architecture and comparable size with the downdip buildups exposed in Red Bluff Creek. These buildups were compared with other outcropping Albian buildups in Texas that have different sizes, shapes, and stratigraphic architecture to provide dimensional data that could be used in subsurface reservoir modeling, either for calibrating variogram ranges or to build training images. The rudist buildups exposed in Texas are an order of magnitude smaller than those present in the subsurface in the Middle East, but they have comparable stratigraphic architecture. The size difference might be the result of subsurface buildups being mapped using well-log or core correlations or seismic extractions that cannot resolved at that scale of heterogeneity.

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Identifying Spatial and Temporal Variations in Concrete Bridges with Ground Penetrating Radar Attributes

Remote Sensing ◽

10.3390/rs13091846 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1846

Author(s):

Vivek Kumar ◽

Isabel M. Morris ◽

Santiago A. Lopez ◽

Branko Glisic

Keyword(s):

Compressive Strength ◽

Ground Penetrating Radar ◽

Material Properties ◽

Temporal Variations ◽

Concrete Bridges ◽

Spatial And Temporal Variation ◽

Reflected Waves ◽

Ground Penetrating ◽

Over Time

Estimating variations in material properties over space and time is essential for the purposes of structural health monitoring (SHM), mandated inspection, and insurance of civil infrastructure. Properties such as compressive strength evolve over time and are reflective of the overall condition of the aging infrastructure. Concrete structures pose an additional challenge due to the inherent spatial variability of material properties over large length scales. In recent years, nondestructive approaches such as rebound hammer and ultrasonic velocity have been used to determine the in situ material properties of concrete with a focus on the compressive strength. However, these methods require personnel expertise, careful data collection, and high investment. This paper presents a novel approach using ground penetrating radar (GPR) to estimate the variability of in situ material properties over time and space for assessment of concrete bridges. The results show that attributes (or features) of the GPR data such as raw average amplitudes can be used to identify differences in compressive strength across the deck of a concrete bridge. Attributes such as instantaneous amplitudes and intensity of reflected waves are useful in predicting the material properties such as compressive strength, porosity, and density. For compressive strength, one alternative approach of the Maturity Index (MI) was used to estimate the present values and compare with GPR estimated values. The results show that GPR attributes could be successfully used for identifying spatial and temporal variation of concrete properties. Finally, discussions are presented regarding their suitability and limitations for field applications.

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Delineating shallow Neogene deformation structures in northeastern Pará State using Ground Penetrating Radar

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652003000200009 ◽

2003 ◽

Vol 75 (2) ◽

pp. 235-248 ◽

Cited By ~ 5

Author(s):

Dilce F. Rossetti

Keyword(s):

Ground Penetrating Radar ◽

Structural Models ◽

Field Studies ◽

Strike Slip ◽

Brittle Deformation ◽

Shallow Subsurface ◽

Deformation Structures ◽

Ground Penetrating ◽

Slip Motion

The geological characterization of shallow subsurface Neogene deposits in northeastern Pará State using Ground Penetrating Radar (GPR) revealed normal and reverse faults, as well as folds, not yet well documented by field studies. The faults are identified mostly by steeply-dipping reflections that sharply cut the nearby reflections causing bed offsets, drags and rollovers. The folds are recognized by reflections that are highly undulating, configuring broad concave and convex-up features that are up to 50 m wide and 80 to 90 ns deep. These deformation structures are mostly developed within deposits of Miocene age, though some of the faults might continue into younger deposits as well. Although the studied GPR sections show several diffractions caused by trees, differential degrees of moisture, and underground artifacts, the structures recorded here can not be explained by any of these ''noises''. The detailed analysis of the GPR sections reveals that they are attributed to bed distortion caused by brittle deformation and folding. The record of faults and folds are not widespread in the Neogene deposits of the Bragantina area. These GPR data are in agreement with structural models, which have proposed a complex evolution including strike-slip motion for this area from the Miocene to present.

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