Sampling and analysis of geothermal fluids

Abstract

Sampling of geothermal fluids presents some problems not encountered when sampling surface and nonthermal ground waters. Specific collection techniques are required to obtain representative samples because of the elevated temperature and boiling of these fluids, the effect of exposing them to the atmosphere and cooling of the samples. Sample treatment during collection depends on the analytical method to be used. When sampling wetsteam wells, both the liquid and the vapour fractions should be collected at the same fluid separation pressure. When sampling fumarole steam, maximum information is obtained if the total discharge is collected into a single container without separating the gas and the steam condensate fractions. Silica polymerization affects the solution pH. The only way to obtain reliable pH measurement of a water sample supersaturated with respect to amorphous silica is to measure it on site, before the onset of polymerization. This paper provides an outline of the geothermal sampling techniques and analytical methods currently in use in Iceland. Sampling of hot-water and wet-steam wells is described, as is sampling of hot springs, fumaroles and gas bubbling through hot-spring waters. Detailed procedures are given for the analysis of total carbonate carbon and total sulphide sulphur in geothermal water and steam condensate samples.

Evolution of fluid geochemistry at the Turrialba volcano (Costa Rica) from 1998 to 2008

“…Such processes can explain the low concentrations of CO, likely resulting by hydrolysis processes in low-temperature fumaroles (Table 1). Timedependent dissolution of CO in NaOH could also explain the lack of CO in the headspace of the sampling flasks (Giggenbach and Matsuo 1991;Arnósson et al 2006). The West HT fumarole, characterized by the highest gas flux, outlet temperature, and CO concentrations (Table 1), was less affected by the shallow level water-gas interactions.…”

Chlorine isotope geochemistry of Icelandic thermal fluids: Implications for geothermal system behavior at divergent plate boundaries

“…From dry vapor well discharges, only the vapor phase was collected. For two-phase well discharges, both the liquid and vapor phases were collected at the wellhead using Webre separator (Arnórsson et al, 2006).…”

Karakteristik Kimia Dan Isotop Fluida Panas Bumi Daerah Gunung Tampomas, Jawa Barat

“…Untuk sampel isotop 18 O dan 2 H digunakan botol sampel 20 mL yang harus terisi penuh sampel tanpa ada gelembung udara untuk meminimalisir fraksinasi isotop. Untuk sampel kation dilakukan penambahan asam hingga pH 2-3, untuk mencegah pengendapan dan polimerisasi silika, sedangkan untuk sampel anion tidak diperlukan perlakuan khusus (Arnórsson et al, 2006;Clark and Fritz, 1997). -11, 2011; D859-16, 2009).…”