The Los Humeros Geothermal Field: On the Acidity of Fluids

Abstract

Evidence from Mineralogical, geochemical and fluid inclusions data have shown the occurrence of two geothermal reservoirs in the Los Humeros Geothermal Field (LHGF) as well as the formation of acid fluids that at once promoted corrosion in well casings. Analysis of production and reservoir engineering data from wells of LHGF, and pressure distribution profiles for the unperturbed system, were used as evidence for the existence of two reservoirs: one of high liquid saturation and other of low liquid saturation.
The unperturbed system did not contain a proper acid zone. No evidence of acid fluids occurring in the reservoirs have been found. The only instance of shallow acidity is the surface argillic alteration as a result of H2SO4 formation. Deep corrosive fluids in wells were formed after the exploitation of the field began.