Chemical Treatments of Fluids at the Miravalles Geothermal Field: Investigation, Application and its Relationship With Reservoir Management

Abstract

Visualizing the commercial exploitation of the Miravalles Geothermal Field without the application of chemical treatments to the produced waters would be impossible, since 25 out of 26 producing wells require these treatments. The CaCO3 scaling is observed in 23 producing wells, which would be obstructed in periods that range from several days to several months without correcting inhibition process. The appropriate chemical treatment of these wells has assured an uninterrupted production for years and continuous operation of the different geothermal plants installed so far. Also, two other production wells present acid fluids and they require an acid neutralization treatment. Without this process the corrosion rate into the wells is so high that it would be impossible to exploit them, even for short periods. These two wells have helped to maintain the mass flow requirements of the geothermal plants, when for some reason some of the neutral-flow producer wells cannot be used.
The present document discusses the experience gained in the investigation and uses of chemical treatments in the fluids of the Miravalles Geothermal Field, in answer to its particular conditions. The investigation is not only focused on the industrial process of the exploitation of these fluids, but also on the impact that these treatments have on the operation and maintenance of the geothermal field, and as an integral part of the reservoir monitoring programs and exploitation policies.