Developing a Calibrated EGS Exploration Metodlogy using the Dixie Valley Geothermal System, A Progress Report

Abstract

A calibrated Engineered Geothermal System (EGS) exploration methodology is being developed using the Basin and Range Dixie Valley Geothermal Wellfield (DVGW) in Nevada and its surroundings as a laboratory test site. Previous reports (Iovenitti et al, 2011a, b; 2012) principally discussed the assessment of the existing published data with some re-interpretation of the structure, seismic, gravity, magnetic, and magnetotelluric (MT) data coupled with geostatistical analysis of the data, and the generation of paired EGS favorability and trust maps. The favorability maps were based on the three primary EGS parameters of interest, temperature, rock type, and stress. The trust maps are essentially reflect the data reliability of the primary parameters of interest. This paper describes the progress towards develops an enhanced (baseline plus new data) model. To reduce uncertainty and improve resolution in the geophysical data used in the baseline analysis, we have collected (1) 278 new gravity station measurements, (2) analysis of records from 42 new ambient seismic noise stations under two 21-station, three-month campaigns, and (3) 70 new MT stations. We discuss the results of enhanced gravity and magnetic modeling, seismic data interpretation, 3D inversion of 94 MT stations (24 existing and 70 new), the empirical temperature-P wave relationship, stress modeling, and conductive and convective thermal modeling.