ALBERT

Description: The Cambrian Mount Simon Sandstone is the major target reservoir for ongoing geologic carbon dioxide (CO 2) sequestration demonstrations throughout the midwest United States. The potential CO 2 reservoir capacity, reactivity, and ultimate fate of injected CO 2 depend on textural and compositional properties determined by depositional and diagenetic histories that vary vertically and laterally across the formation. Effective and efficient prediction and use of the available pore space requires detailed knowledge of the depositional and diagenetic textures and mineralogy, how these variables control the petrophysical character of the reservoir, and how they vary spatially. Here, we summarize the reservoir characteristics of the Mount Simon Sandstone based on examination of geophysical logs, cores, cuttings, and analysis of more than 150 thin sections. These samples represent different parts of the formation and depth ranges of more than 9000 ft (〉2743 m) across the Illinois Basin and surrounding areas. This work demonstrates that overall reservoir quality and, specifically, porosity do not exhibit a simple relationship with depth, but vary both laterally and with depth because of changes in the primary depositional facies, framework composition (i.e., feldspar concentration), and diverse diagenetic modifications. Diagenetic processes that have been significant in modifying the reservoir include formation of iron oxide grain coatings, chemical compaction, feldspar precipitation and dissolution, multiple generations of quartz overgrowth cementation, clay mineral precipitation, and iron oxide cementation. These variables provide important inputs for calculating CO 2 capacity potential, modeling reactivity, and are also an important baseline for comparisons after CO 2 injection.

Description: Concerns about potential climate change related to greenhouse gas emissions have spurred researchers across the world to assess the viability of geologic storage of CO 2 . In the Illinois Basin in the United States, the Cambrian Mount Simon Sandstone has been targeted as a reservoir for carbon capture and storage (CCS). In this CCS system, the Eau Claire Formation is expected to serve as the primary seal to prevent upward migration of the CO 2 plume; however, little work has been done to specifically determine how well it will function as a seal. Although the lateral extent and thickness of the Eau Claire Formation, along with its generally low permeability, certainly make it a prime candidate to serve in this capacity, the primary depositional fabric and mineralogy, which are the fundamental controls on the petrophysical charter of this unit, remain poorly constrained. Therefore, the purpose of this study is to investigate the lithologic, mineralogical, and petrophysical properties of the Eau Claire Formation in an effort to characterize its potential as a functional seal in a CCS system. Sixty-six core-derived Eau Claire Formation samples from seven wells within the Illinois Basin are described using a combination of petrography, reflectance spectroscopy, x-ray diffraction, geochemical, and petrophysical analyses. These analyses show that the Eau Claire Formation contains five different lithofacies (sandstone, clean siltstone, muddy siltstone, silty mudstone, and shale) with fine-scale heterogeneities in fabric and mineralogy that greatly influence the petrophysical properties. Porosity, permeability, and entry-pressure data suggest that some, but not all, lithofacies within the Eau Claire Formation have the capability to serve as a suitable CCS seal. Abundant authigenic minerals and dissolution textures indicate that multiple generations of past fluid-rock interactions have occurred within the Eau Claire Formation, demonstrating that much of the formation has behaved as a fluid conduit instead of as a seal. Minerals that would be potentially reactive in a CCS system (including carbonate, glauconite, and chlorite) are common in the Eau Claire Formation. Dissolution of these and other phases in the presence of carbonic acid could potentially jeopardize the sealing integrity of the unit. Although complexities in the sealing properties exist, the dynamics of the CCS system and the potential for precipitation of new minerals should allow the Eau Claire Formation to serve as an adequate seal.

Description: The Mount Simon Sandstone (Cambrian) has significant potential for use as a reservoir for geologic carbon sequestration in the Midwest region, but lithologic variations within the unit remain poorly understood. Petrophysical heterogeneities controlled by the changes in lithologic and diagenetic character challenge the process of estimating the storage capacity of this reservoir. Geophysical logs from wells across the Midwest region were interpreted to define three lithostratigraphic subunits within the Mount Simon Sandstone: an upper unit that has relatively high gamma-ray (GR) values caused by the admixture of argillaceous material; a middle unit defined by relatively lower GR values that result from a cleaner quartzose sandstone and potentially constitutes the main reservoir and flow unit within the formation (the GR values of this unit also display the lowest amount of vertical variability through the section); and a lowermost unit defined by GR values that, in general, progressively increase with depth toward the base of the formation. This downward increase is caused by the increased nonquartz fraction in the formation as the top of the Precambrian basement is approached. In all three units, but especially in the lowermost one, the admixture of feldspars and the presence of dissolution porosity complicate storage capacity calculation. In addition to quartz overgrowths and compaction phenomena that reduce pore volume, the presence of other diagenetic products further complicates the distribution of porosity and permeability within the unit. Storage capacity was calculated only for the middle unit within the Mount Simon Sandstone using values derived from GR and porosity geophysical logs (sonic, neutron, and density). The range of storage capacity found in this study is primarily controlled by reservoir thickness because the variation in porosity within this middle unit is less than that in the other units. However, an assessment of the vertical distribution of porosity and permeability at each site will be required to determine the best intervals with the best flow and storage properties.

Description: The Eau Claire Formation of the midwestern United States was evaluated for its potential use as a confining unit (seal) overlying a sandstone reservoir to securely store injected $${\mathrm{CO}}_{2}$$ . This evaluation included: (1) lithofacies composition and distribution, (2) capillary entry pressure analysis, and (3) fluid- and fracture-pressure analysis. The regional distribution of lithofacies in the Eau Claire was evaluated by examination of core and log data from selected wells across the study area. Log data were used to define electro-lithofacies, which are spatially variable and represent a mixture of shale, siltstone, sandstone, limestone, and dolomite. Because of the significant variation in lithofacies and the complex spatial distribution, the entire interval should be considered in evaluating the seal capacity of the unit at a given locality. Mercury-injection capillary pressure (MICP) data were obtained on 17 samples of Eau Claire lithofacies ranging from muddy shale to sand/silt to evaluate the potential for capillary entry of fluids into the pore system of the lithofacies of the unit. Interpretation of these data indicated capillary failure of the muddy shale lithofacies is unlikely. However, many of the MICP samples contain millimeter-scale silt/sand interbeds, which would probably allow $${\mathrm{CO}}_{2}$$ entry but, because these beds commonly have very limited lateral continuity, they are very unlikely to provide pathways for large-scale $${\mathrm{CO}}_{2}$$ leakage through the interval. Evaluation of structural settings, lithostatic and existing formation aquifer pressures in the Eau Claire, in conjunction with the height of $${\mathrm{CO}}_{2}$$ columns stored in the underlying Mount Simon Sandstone (Cambrian), suggest that fluid pressures induced by a static buoyant $${\mathrm{CO}}_{2}$$ plume are unlikely to induce fractures in the formation. However, elevation of the aquifer pressure during injection may be capable of creating fractures within the unit.

Description: The successful implementation of geologic carbon sequestration depends on the careful evaluation of the petrophysical characteristics of the storage reservoir. Two petrophysical properties, porosity and permeability, constrain the reservoir in terms of its storage potential and injectivity. These two key parameters may vary significantly in scale within a reservoir. Likewise, the analytical tools that are useful for measuring these properties also vary and only assess pores of a given scale. In this investigation, 52 rock samples that consist of carbonates having a high degree of dolomitization were obtained from the Cambrian–Ordovician Knox Supergroup from different depth intervals; these samples span a significant area of the Midwestern United States. The samples were analyzed for total porosity and pore-size distribution using a variety of techniques, including petrographic image analysis, helium porosimetry, gas adsorption, mercury porosimetry, and ultrasmall-angle/small-angle neutron scattering. Capillary entrapment, or "residual saturation," is that part of the injected CO 2 that remains trapped in micropores after the pressure elevated by the injection process returns to ambient reservoir pressure. Results from low-pressure nitrogen and carbon dioxide adsorption and from mercury injection capillary pressure are important in that they provide insights about small pore size that otherwise cannot be resolved by standard helium porosimetry or by image analysis software. Results from these analyses suggest that micro- and mesoporosity control capillary entrapment, whereas macroporosity controls permeability.

Description: Cambrian–Ordovician strata of the midwestern United States are considered a promising reservoir for geologic storage of carbon dioxide. To assess the potential of the Ordovician St. Peter Sandstone, storage-resource estimates were generated using a hierarchical approach to estimating prospective storage resources. The method employs a series of increasingly sophisticated analyses to better facilitate an understanding of the uncertainty in the estimates. Results demonstrate how uncertainty of storage-resource estimates varies as a function of data availability and quality as well as the underlying assumptions used in the application of specific storage efficiency factors. In the simplest analysis, storage-resource estimates were calculated from updated regional-scale mapping of the gross thickness of the formation and by applying a single best estimate of the mean porosity for the entire formation. This analysis follows the technique prescribed by the US Department of Energy and yields storage-resource estimates ranging from 3.3 to 35.1 billion t CO 2 in the Michigan Basin and 1.0 to 11.0 billion t CO 2 in the Illinois Basin at the 10% and 90% probability levels. The second analysis incorporated generalized models of the diagenetic history of the formation throughout the two basins by implementing depth-dependent functions of porosity that lead to more realistic portrayals of spatially variable results. Similar resource estimates were calculated for the Michigan Basin, but reduced estimates (43%) were found for the Illinois Basin. The third analysis explicitly accounted for the local-scale spatial variability in reservoir quality using net-porosity calculations, resulting in a significant increase in the low-range resource estimate for the Michigan Basin and dramatic increases for Illinois Basin resource estimates (factor of 3 to 11 increases). A fourth analysis was conducted for the Michigan Basin that used advanced reservoir characterization to define reservoir properties for multiple reservoir facies and yielded resource estimates significantly larger than the third analysis and a larger range of uncertainty. This study highlights how different factors impact the expected uncertainty in storage-resource estimates, and analysis suggests that estimates from the first two approaches provide excessively conservative results, whereas the second two approaches tend to overestimate the resource.

Description: The stress regime in the Illinois Basin was investigated to assess how the rock column might respond to the injection of fluids, including coproduced formation brines and supercritical CO 2 .This response is a concern because injection practices could increase pore fluid pressure and potentially induce seismicity. Data were collected to determine the magnitude and orientation of a three-component stress field: vertical stress ( S v ) and minimum ( S h ) and maximum ( S H ) horizontal stresses. The S v was evaluated with a six-layer lithostratigraphic column. A two-layer pressure–depth S v model was generated for the central part of the basin, and a single pressure gradient model was constructed for the surrounding region. In the central part of the basin, the S v gradient is 24.9 MPa/km (1.11 psi/ft) to a depth of 2134 m (7000 ft), followed by a gradient of 27.1 MPa/km (1.20 psi/ft) below 2134 m (7000 ft). For the area surrounding the deep basin, the S v gradient was 25.5 MPa/km (1.13 psi/ft). The S h was evaluated from multiple data sources, primarily hydraulic fracture records or extended leak-off tests. The S h gradient calculations ranged from 24.1 to 27.3 MPa/km (1.07 to 1.21 psi/ft). The S h values for the basal Paleozoic clastic units are lower than those for units in the overlying horizons. The S H was based on a critically stressed model yielding values between 40.0 and 82.6 MPa/km (1.77 to 3.65 psi/ft). Stress orientation data for the Illinois Basin were collected from multiple sources. The orientation of S H across the study area is relatively uniform in strike at approximately N60°E. Marked deviations in S H result from localized structural discontinuities.

Description: Polyacrylamide hydrogels are interesting materials for studying cells and cell–material interactions, thanks to the possibility of precisely adjusting their stiffness, shear modulus and porosity during synthesis, and to the feasibility of processing and manufacturing them towards structures and devices with controlled morphology and topography. In this study a novel approach, related to the processing of polyacrylamide hydrogels using soft-lithography and employing microstructured templates, is presented. The main novelty relies on the design and manufacturing processes used for achieving the microstructured templates, which are transferred by soft-lithography, with remarkable level of detail, to the polyacrylamide hydrogels. The conceived process is demonstrated by patterning polyacrylamide substrates with a set of vascular-like and parenchymal-like textures, for controlling cell populations. Final culture of amoeboid cells, whose dynamics is affected by the polyacrylamide patterns, provides a preliminary validation of the described strategy and helps to discuss its potentials.

Description: Research Highlights: Flammability of wildland fuels is a key factor influencing risk-based decisions related to preparedness, response, and safety in Alaska. However, without effective measures of current and expected flammability, the expected likelihood of active and problematic wildfires in the future is difficult to assess and prepare for. This study evaluates the effectiveness of diverse indices to capture high-risk fires. Indicators of drought and atmospheric drivers are assessed along with the operational Canadian Forest Fire Danger Rating System (CFFDRS). Background and Objectives: In this study, 13 different indicators of atmospheric conditions, fuel moisture, and flammability are compared to determine how effective each is at identifying thresholds and trends for significant wildfire activity. Materials and Methods: Flammability indices are compared with remote sensing characterizations that identify where and when fire activity has occurred. Results: Among these flammability indicators, conventional tools calibrated to wildfire thresholds (Duff Moisture Code (DMC) and Buildup Index (BUI)), as well as measures of atmospheric forcing (Vapor Pressure Deficit (VPD)), performed best at representing the conditions favoring initiation and size of significant wildfire events. Conventional assessments of seasonal severity and overall landscape flammability using DMC and BUI can be continued with confidence. Fire models that incorporate BUI in overall fire potential and fire behavior assessments are likely to produce effective results throughout boreal landscapes in Alaska. One novel result is the effectiveness of VPD throughout the state, making it a potential alternative to FFMC among the short-lag/1-day indices. Conclusions: This study demonstrates the societal value of research that joins new academic research results with operational needs. Developing the framework to do this more effectively will bring science to action with a shorter lag time, which is critical as we face growing challenges from a changing climate.

Description: Modern medicine is challenged by several potentially severe fungal pathogens such as Aspergillus fumigatus, Candida albicans, or Histoplasma capsulatum. Though not all fungal pathogens have evolved as primary pathogens, opportunistic pathogens can still cause fatal infections in immuno-compromised patients. After infection with these fungi, the ingestion and clearance by innate immune cells is an important part of the host immune response. Innate immune cells utilize two different autophagic pathways, the canonical pathway and the non-canonical pathway, also called microtubule-associated protein 1A/1B-light chain 3 (LC3) -associated pathway (LAP), to clear fungal pathogens from the intracellular environment. The outcome of autophagy-related host immune responses depends on the pathogen and cell type. Therefore, the understanding of underlying molecular mechanisms of autophagy is crucial for the development and improvement of antifungal therapies. One of those molecular mechanisms is the interaction of the transcription-factor hypoxia-inducible factor 1α (HIF-1α) with the autophagic immune response. During this review, we will focus on a comprehensive overview of the role of autophagy and HIF-1α on the outcome of fungal infections.