The Neutralization of Acid Fluids: an Alternative of Commercial Exploitation Wells on Los Humeros Geothermal Field

Abstract

The H-43 well on the Los Humeros Geothermal Field (HGF) was opened for production in February 2008 and had 61 t/h of steam flow, 4 t/h of brine flow, wellhead absolute pressure 51.7 bar and 5.2 of pH. In 10 days of constant production, the pH value diminished to 4.4, and the content of iron in the brine increased to 22.9 ppm, which is associated with corrosion of the casing by acid fluids. For steam commercial exploitation it is necessary to neutralize the fluid and so avoid corrosion in the casing and superficial equipment. For this reason, studies were carried out to determine the feasibility of neutralization of acid fluids. The tests in the well initiated in April and concluded in July 2009. Hydroxide of sodium (NaOH) with a concentration of 47 % was injected to 1350 meters depth to neutralize the acid fluid of the well. The results show that the neutralization system is successful. The estimated costs of system implementation are around USD $108,000 and the investment would be recovered in about 14 days, according to the well potential. H-43 well is projected to start production in late December of 2009.

In this paper, we present the results of the neutralization of acid fluids in the H-43 well, with the intention for commercial exploitation in the near future in this zone in the Los Humeros Geothermal Field, and with neutralization to obtain a major efficiency in the productive process.