the S k r  relations are obtained by fitting to experimental data using either an 10 endpoint power law or a modified Corey approach. The six models were tested 11 using data from four well-characterized sandstones (Berea, Paaratte, Tuscaloosa, 12Mt. Simon) for two radial injection test cases. The results show a large variation 13 in plume extent and saturation distribution for each of the sandstones, 14 depending on the used model. The VG-Mualem model predicts plumes that are 15 considerably larger than for the other models due to the overestimation of the 16 gas relative permeability. On the other hand, the predicted plume sizes are the 17 smallest for the VG-Corey model due to the underestimation of the aqueous 18 phase relative permeability. Of the four models that do not use fits to 19 experimental relative permeability data, the hybrid model with Mualem aqueous 20 phase and Corey gas phase relative permeabilities provide the best fits to the 21 experimental data and produce results close to the model with fits to the 22 capillary pressure and relative permeability data. The model with the endpoint 23 power law resulted in very low, uniform gas saturations outside the dry-out 24 zone for the Tuscaloosa sandstone, as the result of a rapidly declining aqueous 25 3 phase relative permeability. This observed behavior illustrates the need to obtain 1 reliable relative permeability relations for a potential reservoir, beyond 2 permeability and porosity data. 3 4

Risk communication literature suggests that for a number of reasons, the public may perceive a risk to be greater than indicated by its statistical probability. Public concern over risk can lead to significant and costly delays in project permitting and operations. Considering these theories, media coverage of CO 2 -related well blowouts in 2013 gave rise to the questions: What is the risk of CO 2 well blowouts associated with CCUS through CO 2 EOR? What is the potential public perception of those risks? What information could be used to respond to public concern? To address these questions, this study aims to: 1) provide a framework for understanding the nature of onshore well blowouts, 2) quantify the incidence of such events for three specific geographic regions of Texas, 3) relate this data to CCUS and findings from other studies, and 4) explore the potential implications for public perception of this risk associated with CCUS projects. While quantifying answers to these questions proved to be challenging, the results from this study suggest that (1) the perceived risk of CO 2 well blowouts may exceed the statistical risk and (2) information that could be used to address this gap could be made more readily available to the greater benefit of industry and stakeholders who support the development of CCUS as an option for addressing anthropogenic CO 2 emissions. The study also suggests approaches to best conduct such data inquiries.

No abstract

Geothermal energy can provide answers to many of America’s essential energy questions. The United States has tremendous geothermal resources, as illustrated by the results of the DOE GeoVision analysis, but technical and non-technical barriers have historically stood in the way of widespread deployment of geothermal energy. The U.S. Department of Energy’s Geothermal Technologies Office within the Office of Energy Efficiency and Renewable Energy has invested more than $470 million in research and development (R&D) since 2015 to meet its three strategic goals: (1) unlock the potential of enhanced geothermal systems, (2) advance technologies to increase geothermal energy on the U.S. electricity grid, and (3) support R&D to expand geothermal energy opportunities throughout the United States. This paper describes many of those R&D initiatives and outlines future directions in geothermal research.

No abstract