Improvements in 2016 to Natural Reservoir Analysis in Low-Temperature Geothermal Play Fairway Analysis for the Appalachian Basin

This Department of Energy funded effort applied the Play Fairway Analysis approach to low-temperature geothermal exploration and potential development of direct-use geothermal plays in the Appalachian Basin portions of New York, Pennsylvania, and West Virginia. The four “Play Fairway” risk factors analyzed in this study are 1) thermal resource quality, 2) natural reservoir quality, 3) induced seismicity, and 4) utilization opportunities. This project considered several methodologies for combining the risk factors into a single index that communicates the estimated overall favorability of geothermal development. Uncertainty analyses considered the estimated precision in the geologic risk factors (1-3) and estimated the uncertainty in the combined index. The assumed use scenario investigated on a basin-wide scale was that of district heating systems. The quantitative analysis was based on pre-existing data from sources inclusive of: previous national and state research efforts; the National Geothermal Data System; the Midwest Regional Carbon Sequestration Partnership; New York, Pennsylvania and West Virginia State geologic, oil and gas well data provided by the State Geological Surveys and by their oil and gas regulatory bodies; NOAA Climate data; NEIC and EarthScope (TA) seismicity data; a regional-scale magnetic grid; regional-scale gravity data; the World Stress Map; US Census Bureau population data; and Energy Information Agency power consumption data. Based on these data and metrics, several geothermal plays in the Appalachian Basin were identified as potentially viable for direct-use-heat applications. Major uncertainties remaining at the end of this analysis are especially large regarding characterization of reservoirs to flow hot water, and regarding the three-dimensional spatial distribution of reservoirs because the data are biased by the hydrocarbon industry source of data. In addition, although the general spatial patterns of the heat resource variations appear to be robust, the accuracy of the temperature-depth profiles at given locations of interest could be improved significantly if new equilibrium temperature and thermal conductivity data were acquired. As a follow-up step, the subsurface costs for a set of case study scenarios should be analyzed as well as the surface infrastructure costs, to facilitate Levelized Cost of Heat discussions with potential user groups at favorable locations. The methodologies developed in this project may be applied in other sedimentary basins as a foundation for low temperature (50-150 °C) direct use geothermal resource, risk, and uncertainty assessment. DISCLAIMER The information, data, or work presented herein was funded in part by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. NOTE This document is a slightly augmented and updated version of the Executive Summary from Jordan et al. (2015). Please consult that document after its public release for more details.