“…Natural state geothermal reservoir models describe the subsurface temperature and pressure distribution, the location and depth of boiling zones, and the rates of heat and mass transport prior to the onset of exploitation (M. O’Sullivan et al., 2001; M. O’Sullivan & O’Sullivan, 2016). As the subsurface dynamics of fluid flow and heat transfer control the sustainable level of power generation that a geothermal system can support, the natural state models serve as the basis for numerical models calibrated using production history data that evaluate the future response of the system to production (Arellano et al., 2011; Bodvarsson et al., 1987; G. Björnsson et al., 2003; Gunnarsson et al., 2010; Romagnoli et al., 2010; J. O’Sullivan et al., 2015; Ratouis et al., 2016; Rop et al., 2018; Sutopo et al., 2019). Even in geothermal systems such as Krafla that have been exploited for several decades, there is a paucity of data needed to fully constrain the system structure, and the uncertainty of natural state models is significant.…”