A new improved Na/K geothermometer by artificial neural networks

Assessment of performance and parameter sensitivity of multicomponent geothermometry applied to a medium enthalpy geothermal system

“…The ranges of temperatures for the springs in the Villarrica area and for the , AND andesite experiment (180 days)] using classical solute geothermometers (light grey) compared to temperature distributions derived from multicomponent geothermometry (dark grey). Classical solute geothermometer temperatures (SiO 2 , Na/K, Na/K/Ca, K/Mg, Li/Mg and Na/Li) were calculated using formulations of Arnórsson (1983), Can (2002, Diaz-Gonzalez et al (2008), Fouillac and Michard (1981), Fournier (1977, 1979, Fournier and Potter (1982), Fournier and Truesdell (1973), Giggenbach (1988), Kharaka and Mariner (1989), Michard (1990), Nieva and Nieva (1987), Tonani (1980), andVerma andSantoyo (1997) Page 10 of 20 Nitschke et al Geotherm Energy (2017) 5:12 fluids derived from the experiments calculated by multicomponent geothermometry are significantly smaller as compared to the very large spread obtained from classical solute geothermometers. Despite special attention paid to the applicability of each solute geothermometer, it is shown that classical geothermometers generally lead to a broad spread of temperatures of, in some cases, ≫100 K. The spread of temperatures derived from multicomponent geothermometry is much smaller.…”

“…The detailed chemical compositions (major constituents) are depicted in Appendix. Figure 4 provides a comparison of temperatures derived from multicomponent geothermometry (preliminary temperatures without correction of dilution, pH and aluminum concentration) to results calculated by a suite (n = 23) of classical solute geothermometers (SiO 2 , Na/K, Na/K/Ca, K/Mg, Li/Mg and Na/Li geothermometers according to the equations given by Arnórsson (1983), Can (2002), Diaz-Gonzalez et al (2008) Fouillac andMichard (1981), Fournier (1977Fournier ( , 1979, Fournier and Potter (1982), Fournier and Truesdell (1973), Giggenbach (1988), Kharaka and Mariner (1989), Michard (1990), Nieva and Nieva (1987), Tonani (1980), and Verma and Santoyo (1997). The results were depicted as boxplots, plotting the mean (median value) equilibration temperature, the lower and upper quartiles (comprising 50% of all temperatures) and the lower and upper extremes.…”

“…Deducing these temperatures from the chemical composition of geothermal fluids emerging at the earth's surface is a commonly used and relatively cost-effective method. Over more than five decades a large number of solute geothermometers have been established and constantly improved [e.g., Fournier and Rowe (1966), Giggenbach (1988), Can (2002), Sanjuan et al (2014)]. Many of these interrelations, linking the concentration of one constituent or the ratios…”

Solute and gas geothermometry of geothermal wells: a geochemometrics study for evaluating the effectiveness of geothermometers to predict deep reservoir temperatures

“…In this work, cation geothermometry is based on the available 12 Na/K geothermometers in the literature (i.e. Fournier and Truesdell 1973;Truesdell 1976;Fournier 1979;Tonani 1980;Giggenbach 1988;Verma and Santoyo 1997;Arnórsson 2000b;Can 2002;; see a list of all solute geothermometer equations in Table 1, Verma et al 2008). To apply correctly all Na/K International Geology Review 2021 …”

Carbon dioxide degassing flux from two geothermal fields in Tibet, China

“…The SI, fractional pressure and TDIC were calculated using the PHREEQC model [64]. We used Can's Na/K equation to calculate a geothermometer (T N-K ) [65], the normalized mean square error of which was 0.179°C.…”