11 research outputs found
Scaling Behavior of Ricci Curvature at Short Distance near Two Dimensions
We study the renormalization of the Ricci curvature as an example of
generally covariant operators in quantum gravity near two dimensions. We find
that it scales with a definite scaling dimension at short distance. The Ricci
curvature singularity at the big bang can be viewed as such a scaling
phenomenon. The problem of the spacetime singularity may be resolved by the
scale invariance of the spacetime at short distance.Comment: 9pages, LaTe
TolerĂąncia de genĂłtipos de cafeeiro ao alumĂnio em solução nutritiva. II. Teores de P, Ca e Al e eficiĂȘncia ao P e Ca
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Dynamic risk assessment for geologic CO2 sequestration
At a geologic CO2 sequestration (GCS) site, geologic uncertainty usually leads to large uncertainty in the predictions of properties that influence metrics for leakage risk assessment, such as CO2 saturations and pressures in potentially leaky wellbores, CO2/brine leakage rates, and leakage consequences such as changes in drinking water quality in groundwater aquifers. The large uncertainty in these risk-related system properties and risk metrics can lead to over-conservative risk management decisions to ensure safe operations of GCS sites. The objective of this work is to develop a novel approach based on dynamic risk assessment to effectively reduce the uncertainty in the predicted risk-related system properties and risk metrics. We demonstrate our framework for dynamic risk assessment on two case studies: a 3D synthetic example and a synthetic field example based on the Rock Springs Uplift (RSU) storage site in Wyoming, USA. Results show that the U.S. National Risk Assessment Partnership's Open Source Integrated Assessment Model (NRAP-Open-IAM) coupled with a conformance evaluation can be used to effectively quantify and reduce the uncertainty in the predictions of risk-related system properties and risk metrics in GCS
Great SCO2T! Rapid Tool for Carbon Sequestration Science, Engineering, and Economics
CO2 capture and storage (CCS) technology is likely to be widely deployed in the coming decades in response to major climate and economics drivers: CCS is part of every clean energy pathway that limits global warming to 2 °C or less and receives significant CO2 tax credits in the United States. These drivers are likely to stimulate the capture, transport, and storage of hundreds of millions or billions of tonnes of CO2 annually. A key part of the CCS puzzle will be identifying and characterizing suitable storage sites for vast amounts of CO2. We introduce a new software tool called SCO2T (Sequestration of CO2 Tool, pronounced âScottâ), a dynamic CO2 injection and storage model, to rapidly characterize saline storage reservoirs. The tool is designed to rapidly screen hundreds of thousands of reservoirs, perform sensitivity and uncertainty analyses, and link sequestration engineering (injection rates, reservoir capacities, plume dimensions) to sequestration economics (costs constructed from around 70 separate economic inputs). We describe the novel science developments supporting SCO2T including a new approach to estimating CO2 injection rates and CO2 plume dimensions as well as key advances linking sequestration engineering with economics. We perform a sensitivity and uncertainty analysis of geology parameter combinationsâincluding formation depth, thickness, permeability, porosity, and temperatureâto understand the impact on carbon sequestration. Through the sensitivity analysis, we show that increasing depth and permeability both can lead to increased CO2 injection rates, increased storage potential, and reduced costs, while increasing porosity reduces costs without impacting the injection rate (CO2 is injected at a constant pressure in all cases) by increasing the reservoir capacity. Through uncertainty analysisâwhere formation thickness, permeability, and porosity are randomly sampledâwe show that final sequestration costs are normally distributed with upper bound costs around 50% higher than the lower bound costs. While site selection decisions will ultimately require detailed site characterization and permitting, SCO2T provides an inexpensive dynamic screening tool that can help prioritize projects based on the complex interplay of reservoir, infrastructure (e.g., proximity to pipelines), and other (e.g., land use, legal) constraints on the suitability of certain regions for CCS