Physical Properties of Geomaterials Datasets

Physical Properties of Geomaterials Datasets Santamarina, J. Carlos; Roshankhah, Shahrzad Abstract for Chapter 3 dataset: Energy-related geosystems often impose extreme temperatures and loading conditions on the surrounding medium, so granular materials must be selected or engineered to satisfy heat transfer requirements and mechanical stability. In this work, the thermo-mechanical response of some natural and engineered granular materials was investigated by subjecting dense specimens to vertical load under zero lateral strain boundary conditions with concurrent thermal conductivity measurements. The materials studied were quartzitic sand with and without metal coatings, fly ash, diatomaceous earth, ceramic microspheres and hollow glass microspheres. Dry and densely packed hollow glass microspheres, ceramic microspheres and naturally occurring diatomaceous earth were found to be more compressible than sands, but exhibited very low thermal conductivity and very low stress-dependent gain in thermal conductivity. At the other extreme, dense sands combined the high thermal conductivity of quartz with the benefits of metal coatings to render the highest thermal conductivity values among the tested materials; while mechanically stable, dense sands were found to experience pronounced changes in thermal conductivity with stress. Analytical predictions show that saturation with high thermal conductivity liquids will enhance the effective thermal conductivity of granular materials more than the changes attained with metal coatings. Interparticle heat conduction processes and contact resistance explain the measured conductivity values obtained with the granular materials tested in this study.; Abstract for Chapter 4 dataset: Granular materials can be engineered to enhance their performance under imposed hydro-thermo-chemo-mechanical coupled excitations. The compressibility and thermal conductivity of granular materials depend on mineralogy, fabric and pore fluid characteristics. A series of zero lateral strain loading experiments are conducted on binary mixtures of silica sand (D50 = 300 μm) and silica flour (D50 = 20 μm) saturated with air, water, and thermal grease. Concurrent measurements of specimen settlement and thermal conductivity during loading and unloading show the evolution of dry mass density (or porosity) and thermal conductivity. In dry mixtures, the mass density reached a maximum value when the fines content is between 0.2 and 0.4, i.e., when fines fill pores between the large grains; yet the peak in thermal conductivity is observed at a 0.4-0.5 fines content and it is 20% to 50% higher than either the clean sand or the fines alone. Liquids facilitate heat conduction and the thermal conductivity of water-saturated specimens is one order of magnitude higher than that of dry specimens with the same fines fraction. Saturation with thermal grease has a lesser effect than water as its high viscosity hinders densification. Liquid saturation, mineralogy, grain coating (investigated in Chapter 3), binary mixtures, and stress can be used to control the thermal conductivity of granular materials. Liquid-saturation is the most effective variable that can be used to enhance thermal conductivity.; Abstract for Chapter 5 dataset: The thermal conductivity of viscous oil-bearing sands determines the evolution of the heat front, the design of steam injection and the optimum location of production wells in thermally enhanced oil recovery methods. Also, the evolution of mid- and small-strain stiffness with temperature and stress is the key for wellbore stability and region subsidence calculations upon the oil production. This study aims to investigate the effect of oil viscosity on compression index and small-strain stiffness Gmax [MPa] of viscous oil-bearing sediments and the stress- and temperature-dependency of their thermal conductivity. Data files are in the Microsoft excel format. Data files are separated by Chapter, corresponding to Chapter 3, 4, and 5 in Shahrzad Roshankhah's forthcoming thesis. The purpose of the study was to investigate the evolution of thermal conductivity and mid-strain stiffness of various granular materials in Chapter 3, and those of binary granular mixtures in Chapter 4 with stress, and those of oil sands in Chapter 5 with stress and temperature. Also, the evolution of small-strain stiffness with stress and temperature has been explored for oil sands in Chapter 5. More detailed descriptions about the datasets have been provided in the corresponding ReadMe files for each chapter.

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