Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Discipline
Articles 1 - 3 of 3
Full-Text Articles in Physical Sciences and Mathematics
Estimation Of Porosity And Water Saturation In Dual-Porosity Pyroclastic Deposits From Joint Analysis Of Compression, Shear, And Electromagnetic Velocities, Andrew C. Gase, John H. Bradford, Brittany D. Brand
Estimation Of Porosity And Water Saturation In Dual-Porosity Pyroclastic Deposits From Joint Analysis Of Compression, Shear, And Electromagnetic Velocities, Andrew C. Gase, John H. Bradford, Brittany D. Brand
Geosciences Faculty Publications and Presentations
In situ measurements of porosity and water saturation of pyroclastic deposits have the potential to improve interpretations of geology and hydrology in volcanic regions, and to provide more accurate estimates of dense rock equivalent for volcanic eruptions. However, rock-property models must consider the dual-porosity structure of pyroclastic deposits (i.e., vesicles within pumices and intergranular pores). Vesicularity, intergranular porosity, and water saturation all affect the density, elasticity, and dielectric properties of pyroclastic materials, which control seismic and electromagnetic velocities. The data from active seismic and ground-penetrating radar (GPR) techniques may improve porosity and water saturation estimation if the responses of seismic …
Capacitive Conductivity Logging And Electrical Stratigraphy In A High-Resistivity Aquifer, Boise Hydrogeophysical Research Site, C. Jonathan Mwenifumbo, Warren Barrash, Michael D. Knoll
Capacitive Conductivity Logging And Electrical Stratigraphy In A High-Resistivity Aquifer, Boise Hydrogeophysical Research Site, C. Jonathan Mwenifumbo, Warren Barrash, Michael D. Knoll
CGISS Publications and Presentations
We tested a prototype capacitive-conductivity borehole tool in a shallow, unconfined aquifer with coarse, unconsolidated sediments and very-low-conductivity water at the Boise Hydrogeophysical Research Site (BHRS). Examining such a high-resistivity system provides a good test for the capacitive- conductivity tool because the conventional induction- conductivity tool (known to have limited effectiveness in high-resistivity systems) did not generate expressive well logs at the BHRS. The capacitive-conductivity tool demonstrated highly repeatable, low-noise behavior but poor correlation with the induction tool in the lower-conductivity portions of the stratigraphy where the induction tool was relatively unresponsive. Singular spectrum analysis of capacitive- conductivity logs reveals …
Estimating Porosity With Ground-Penetrating Radar Reflection Tomography: A Controlled 3-D Experiment At The Boise Hydrogeophysical Research Site, John H. Bradford, William P. Clement, Warren Barrash
Estimating Porosity With Ground-Penetrating Radar Reflection Tomography: A Controlled 3-D Experiment At The Boise Hydrogeophysical Research Site, John H. Bradford, William P. Clement, Warren Barrash
CGISS Publications and Presentations
To evaluate the uncertainty of water-saturated sediment velocity and porosity estimates derived from surface-based, ground-penetrating radar reflection tomography, we conducted a controlled field experiment at the Boise Hydrogeophysical Research Site (BHRS). The BHRS is an experimental well field located near Boise, Idaho. The experimental data set consisted of 3-D multioffset radar acquired on an orthogonal 20 × 30 m surface grid that encompassed a set of 13 boreholes. Experimental control included (1) 1-D vertical velocity functions determined from traveltime inversion of vertical radar profiles (VRP) and (2) neutron porosity logs. We estimated the porosity distribution in the saturated zone using …