Charlotte Garing

Soil water retention parameters (SWRPs) are ubiquitously required in several hydrological and biogeochemical models to simulate water movement, contaminant fate and transport, and gas diffusion in soils. While SWRPs are typically measured in the lab, these measurements vary significantly from field‐based hydrology. Hence, using lab‐measured parameters to make field‐based decisions can result in large uncertainties in hydrological and biogeochemical fluxes. In this work, we identified the hydrologic conditions and scales at which the use of lab‐ and field‐based measurements of SWRPs and derived oxygen diffusivity are equivalent. We compared retention curves measured in the lab and field for Ultisols under corn plantation, and their impact on modeled gas diffusion through soils at two scales: the soil core scale and the field scale. Our results demonstrate that no retention parameters measured in the lab and field were equivalent at the core scale. However, all parameters except for saturated water content (45.36% in the lab vs. 21.58% in the field) were equivalent ( p < 0.05) when averaged at the field scale. We also found that oxygen diffusivity calculated using lab‐based SWRPs represented field conditions if moisture and scale are considered. Specifically, diffusivity calculated based on SWRPs measured in the lab was equivalent to the diffusivity calculated using field‐based SWRPs when averaged for the field scale under well‐drained conditions, but not at moisture contents greater than field capacity. At the core scale, equivalence was not observed for any moisture condition. Additionally, we also determined that the SWRP required to upscale diffusivity values to the field scale is linked to the parameter representing pore size distribution. The findings from this study provide guidance to the hydrological and biogeochemical modeling community for using lab‐measured SWRPs to make field‐based decisions.

Evolution of Transport and Mechanical Properties of Different Mineral Dissolution Patterns.

Geomechanical response of CO2 sequestration reservoirs due to different carbonate dissolution patterns

Coupled geochemical-geomechanical alteration of sandstone in CO2 sequestration reservoirs.

Coupled geochemical-geomechanical processes in CO2 sequestration reservoirs in Southeast, US

Coupled geochemical-geomechanical processes in CO2 sequestration reservoirs in Southeast, US

Accurate determination of petrophysical and multiphase flow properties in sandstones is necessary for reservoir characterization, for instance for carbon dioxide and hydrogen storage in geological formations or for enhanced oil recovery. Several studies have examined the effect of heterogeneities, such as fractures, bedding planes, and laminae, on core‐scale fluid flow. However, the influence of deformation bands that commonly occur in high porosity sandstones is poorly understood. In this study, we consider a core sample of Navajo sandstone characterized by diagonally oriented deformation bands and two laminae perpendicular to the core axis, as determined from micro X‐ray computed tomography (micro‐CT). Positron emission tomography is used to derive the single phase hydrodynamic properties of the core. A CO₂ drainage experiment is conducted in the water‐saturated core and imaged with a medical X‐ray CT scanner. Medical CT enables CO₂ saturation quantification with increasing CO₂ injection rate. Experimental results and the accompanying numerical simulations indicate that both the laminae and the deformation bands act as capillary barriers, with the laminae forming weaker capillary barriers than the deformation bands. The deformation bands have lower permeability and porosity due to grain crushing, and a very high capillary entry pressure that inhibits CO₂ migration across the bands. At the reservoir scale, deformation bands form conjugate sets and are often present in thick anastomosing clusters that define lozenge‐shaped compartments. These findings have important consequences for subsurface fluid flow. For example, the presence of deformation bands may reduce the storage capacity and injectivity in carbon storage reservoirs.