The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

David Healy - One of the best experts on this subject based on the ideXlab platform.

  • quantification of groundwater storage heterogeneity in weathered fractured Basement Rock aquifers using electrical resistivity tomography sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to

  • Quantification of groundwater storage heterogeneity in weathered/fractured Basement Rock aquifers using electrical resistivity tomography: sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to

Jesús Alberto Mézquita González - One of the best experts on this subject based on the ideXlab platform.

  • quantification of groundwater storage heterogeneity in weathered fractured Basement Rock aquifers using electrical resistivity tomography sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to

  • Quantification of groundwater storage heterogeneity in weathered/fractured Basement Rock aquifers using electrical resistivity tomography: sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to

Nan Huai - One of the best experts on this subject based on the ideXlab platform.

  • A story of regolith told by Lunar Penetrating Radar
    Icarus, 2019
    Co-Authors: Ling Zhang, Zhijun Huo, Zhaofa Zeng, Jianmin Zhang, Ling Huang, Jing Li, Nan Huai
    Abstract:

    Knowledge of the lunar regolith not only provides important information about lunar geology, but is also critical to quantifying potential resources for lunar exploration and engineering for human outposts. The Lunar Penetrating Radar (LPR) onboard China's Chang'E-3 (CE-3) provides a unique opportunity for mapping the subsurface structure and the near-surface stratigraphic structure of the regolith. A radar image with high resolution can be produced using a data processing pipeline. The contact interface of the regolith and the Basement Rock is explored according to forward simulation results. F-K (Frequency-wavenumber) filtering that highlights the contact surface of the regolith and the Basement Rock is carried out. The energy distribution of the LPR data helps to stratify the lunar regolith. Finally, by combining this with the history of the Moon, regional geology, and particularly the LPR data, we deduce the evolution of the regolith on the CE-3 landing site.

Ilmo Kukkonen - One of the best experts on this subject based on the ideXlab platform.

  • Prospects for Assessing Enhanced Geothermal System (EGS) Basement Rock Flow Stimulation by Wellbore Temperature Data
    Energies, 2017
    Co-Authors: Peter Leary, Peter Malin, Tero Saarno, Ilmo Kukkonen
    Abstract:

    We use Matlab 3D finite element fluid flow/transport modelling to simulate localized wellbore temperature events of order 0.05–0.1 °C logged in Fennoscandia Basement Rock at ~1.5 km depths. The temperature events are approximated as steady-state heat transport due to fluid draining from the crust into the wellbore via naturally occurring fracture-connectivity structures. Flow simulation is based on the empirics of spatially-correlated fracture-connectivity fluid flow widely attested by well-log, well-core, and well-production data. Matching model wellbore-centric radial temperature profiles to a 2D analytic expression for steady-state radial heat transport with Peclet number Pe ≡ r0φv0/D (r0 = wellbore radius, v0 = Darcy velocity at r0, φ = ambient porosity, D = Rock-water thermal diffusivity), gives Pe ~ 10–15 for fracture-connectivity flow intersecting the well, and Pe ~ 0 for ambient crust. Darcy flow for model Pe ~ 10 at radius ~10 m from the wellbore gives permeability estimate κ ~ 0.02 Darcy for flow driven by differential fluid pressure between least principal crustal stress pore pressure and hydrostatic wellbore pressure. Model temperature event flow permeability κm ~ 0.02 Darcy is related to well-core ambient permeability κ ~ 1 µDarcy by empirical poroperm relation κm ~ κ exp(αmφ) for φ ~ 0.01 and αm ~ 1000. Our modelling of OTN1 wellbore temperature events helps assess the prospect of reactivating fossilized fracture-connectivity flow for EGS permeability stimulation of Basement Rock.

  • Calibrating the EGS Flow Stimulation Process for Basement Rock
    2017
    Co-Authors: Peter Leary, Peter Malin, Tero Saarno, Ilmo Kukkonen
    Abstract:

    We use Matlab 3D finite element fluid flow/transport modelling to simulate localized wellbore temperature events of order 0.05-0.1oC logged in Fennoscandia Basement Rock at ~ 1.5km depths. The temperature events are approximated as steady-state heat transport due to fluid draining from the crust into the wellbore via naturally occurring fracture-connectivity structures. Flow simulation is based on the empirics of spatially-correlated fracture-connectivity fluid flow widely attested by well-log, well-core, and well-production data. Matching model wellbore-centric radial temperature profiles to a 2D analytic expression for steady-state radial heat transport with Peclet number Pe ≡ r0φv0/D (r0 = wellbore radius, v0 = Darcy velocity at r0, φ = ambient porosity, D = Rock-water thermal diffusivity), gives Pe ~ 10-15 for fracture-connectivity flow intersecting the well, and Pe ~ 0 for ambient crust. Darcy flow for model Pe ~ 10 at radius ~ 10 meters from the wellbore gives permeability estimate κ ~ 0.02Darcy for flow driven by differential fluid pressure between least principal crustal stress pore pressure and hydrostatic wellbore pressure. Model temperature event flow permeability κm ~ 0.02Darcy is related to well-core ambient permeability κ ~ 1µDarcy by empirical poroperm relation κm ~ κ exp(αmφ) for φ ~ 0.01 and αm ~ 1000. Our modelling of wellbore temperature events calibrates the concept of reactivating fossilized fracture-connectivity flow for EGS permeability stimulation of Basement Rock.

Jean-christophe Comte - One of the best experts on this subject based on the ideXlab platform.

  • quantification of groundwater storage heterogeneity in weathered fractured Basement Rock aquifers using electrical resistivity tomography sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to

  • Quantification of groundwater storage heterogeneity in weathered/fractured Basement Rock aquifers using electrical resistivity tomography: sensitivity and uncertainty associated with petrophysical modelling
    Journal of Hydrology, 2021
    Co-Authors: Jesús Alberto Mézquita González, Jean-christophe Comte, Anatoly Legchenko, Ulrich Ofterdinger, David Healy
    Abstract:

    Abstract Quantifying groundwater storage in weathered/fractured Basement Rock aquifers can be challenging owing to both their high degree of heterogeneity and their overall low storage capacity. Therefore, in these aquifers, the use of direct borehole hydraulic data is usually insufficient. Here we assessed the popular method of electrical resistivity tomography (ERT), combined with borehole data and including associated uncertainties, to resolve the spatial variability of groundwater storage properties at high resolution within a fractured mica schist aquifer in Ireland. Porosity distributions across both the saturated and unsaturated zones were calculated from two-dimensional (2D) ERT resistivities using two standard petrophysical models, Archie and Waxman & Smits (WS), the latter accounting for the influence of clay minerals on resistivity data. Our results demonstrated the importance of the hydrogeological conceptual constraints provided by ERT when parametrizing the 2D petrophysical models from borehole point data. They also confirmed the importance of accounting for clay minerals (the products of bedRock weathering processes) in the WS model, whereas predictions from Archie’s model produced unrealistically high porosity values of over an order of magnitude higher than the WS model. The WS model predicted porosities decreasing exponentially with depth, with values ranging from a few % in the shallowest, most-weathered part of the bedRock (upper 5 m on average) and deep fractured zones (to about 20 m deep), to