Scrubbing process and chemical equilibria controlling the composition of light hydrocarbons in natural gas discharges: An example from the geothermal fields of El Salvador

摘要: [1] The compositional features of fluids from both fumarolic discharges and productive geothermal wells Ahuachapan-Chipilapa, Berlin-Chinameca, San Vicente systems (El Salvador) are described discussed in order to investigate the complex geochemical interactions involving within shallowest part hydrothermal circulation pathways. Our results highlight that secondary processes able strongly affect modify chemical characteristics gases once they discharge surface as natural manifestations, mainly relation chemical-physical properties each gas species. The effects dissolution shallow aquifers gas-water-rock on composition make it difficult get a correct evaluation thermodynamic conditions characterize reservoirs by applying common geoindicators based equilibria H2O-CO2-H2-CH4-CO system. Differently, C1-C2-C3 alkanes C3 C4 alkane-alkene pair, established under control reactions, remains stable samples collected discharging vents. These suggest relative abundances hydrocarbons characterized similar structure molecular size seem be regulated diffusion velocity through liquid-dominated Therefore light organic fraction naturally can successfully utilized for reservoir temperatures redox conditions, providing useful indications terms exploration exploitation. On this basis, distribution, speciation, also considered highly promising monitoring active volcanic systems.