Development of Shallow (2-m) Temperature Survey Standard Operating Procedures and Interpretation Workbook

Abstract

Shallow (1-2 m) temperature surveys have been deployed in the Great Basin region of the western United States to identify and characterize geothermal resources for over 40 years. The physiographic characteristics of low rainfall (that can suppress or conceal shallow thermal anomalies) and basins with low-thermal-conductivity alluvial fan sediments make shallow temperature survey techniques especially effective in this region. Since the mid-2000s, a group centered at the Great Basin Center for Geothermal Energy (GBCGE) modernized the technique and deployed it for greenfield exploration and mapping of shallow thermal outflow plumes. Since then, several industry and research groups (including the Navy Geothermal Program Office) developed their own systems and methodologies for the collection and interpretation of shallow temperature surveys. Growing interest in geothermal exploration, and the 2-m temperature survey technique in particular, has prompted a review and re-evaluation of best practices and interpretation techniques for shallow temperature surveys and the need to standardize procedures to allow for comparison between surveys conducted by different organizations. Here, we present an equipment inventory as well as standard operating procedures for 2-m survey data collection using the GBCGE 2-m temperature survey rig. In addition, we present progress on a Python notebook that is intended to assist with data processing and interpretation of 2-m temperature survey results. This workbook walks through various data processing tasks such as multi-survey normalization, removal of seasonal temperature effects through establishment of background temperatures, identification and removal of non-geothermal anomalies due to surface albedo and elevation, calculation of estimated heat loss, and geostatistical analyses for interpolation and simulation. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.